WO2025024562A1

WO2025024562A1 - Reach assist motion for computer-assisted systems

Info

Publication number: WO2025024562A1
Application number: PCT/US2024/039359
Authority: WO
Inventors: Goran A. LYNCH; Mohsen Saadat; Amin ZEIAEE
Original assignee: Intuitive Surgical Operations Inc
Current assignee: Intuitive Surgical Operations Inc
Priority date: 2023-07-24
Filing date: 2024-07-24
Publication date: 2025-01-30
Anticipated expiration: 2026-01-24

Abstract

Disclosed is determining to command reach assist motion for a computer-assisted system including a repositionable assembly. The repositionable assembly includes a proximal repositionable structure having a distal portion, a distal repositionable structure that supports an instrument, a sensor system, an input device, and a control system. The control system is configured to command motion of a plurality of joints that pivots the distal portion about a remote center of motion in response to receiving a motion command from the input device. The control system is further configured to determine, based on sensor signals generated by the sensor system, to reconfigure the proximal repositionable structure and command, in response to determining to reconfigure the proximal repositionable structure, the proximal repositionable structure to move the distal portion relative to the workspace such that the reachable space of the instrument is moved relative to the workspace.

Description

REACH ASSIST MOTION FOR COMPUTER-ASSISTED SYSTEMS

RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63/515,320, filed July 24, 2023, and entitled “Reach Assist Motion for Computer-assisted Systems” and U.S. Provisional Application No. 63/603,932, filed November 29, 2023, and entitled “Reach Assist Motion for Computer-assisted Systems.” The subject matter of each of these applications is incorporated by reference herein.

TECHNICAL FIELD

[0002] The present disclosure relates generally to computer-assisted systems and more particularly to adjusting the reachable space of instruments supported by computer-assisted systems.

BACKGROUND

[0003] Computer-assisted systems are often used to perform or assist procedures in a workspace. In an example computer-assisted system with teleoperation, an operator at a user input system manipulates a leader device (e.g„ an input device configured to accept commands for a follower device) to cause motions of a follower device (e.g„ a repositionable assembly that can be teleoperated, and comprising a repositionable structure with or without a supported instrument). In an example, motions of the leader device relative to an operator frame of reference are used to determine corresponding motion commands for the follower device relative to a field of view of an imaging device.

[0004] For example, a computer-assisted system can include a repositionable assembly that includes a proximal repositionable structure and one or more distal repositionable structures. The one or more distal repositionable structures are attached to a distal portion of the proximal repositionable structure. The one or more distal repositionable structures are each configured to support one or more instruments . While the computer-assisted system operates the repositionable assembly to move the instrument s) within a workspace, the driven motions of the repositionable assembly are often determined to, or limited by mechanical design to, pivot the distal portion of the proximal repositionable structure about a remote center of motion (RCM) or translate the one or more instruments parallel to an insertion axis (e.g. in an insertion or retraction direction relative to the one or more instrument(s)). Because movement of the instrument(s) and distal repositionable structure(s) are limited, the workspace that can be reached by the end effectors of the one or more instruments when the distal portion is also limited.

[0005] Accordingly, improved techniques for moving the workspace and adjusting the reach of instruments supported by a computer-assisted system are desirable.

SUMMARY

[0006] Consistent with some embodiments, a computer-assisted system includes a repositionable assembly. The repositionable assembly includes a proximal repositionable structure. The proximal repositionable structure includes a distal portion and a plurality of joints coupling the distal portion to a base. The plurality of joints provides sufficient degrees of freedom to allow a range of joint states of the plurality of joints for a same state of the distal portion. The repositionable assembly further includes a distal repositionable structure attached to the distal portion. The distal repositionable structure is configured to support and move a working portion of an instrument within a reachable space. The repositionable assembly additional includes a sensor system configured to provide sensor signals indicative of physical configurations of the repositionable assembly. The repositionable assembly also include a control system comprising one or more processors. The control system is configured to command, in response to receiving a motion command from an input device, motion of the plurality of joints that pivots the distal portion about a remote center of motion located at a first location relative to a workspace; determine, based on at least the sensor signals, whether to command a reconfiguration of the proximal repositionable structure to move the distal portion relative to the workspace, such that the reachable space is moved relative to the workspace; and command, in response to a determination to command the reconfiguration, the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, such that the reachable space is moved relative to the workspace and the remote center of motion is maintained at the first location.

[0007] Consistent with some embodiments, a method of operating a repositionable assembly includes commanding, by a control system in response to receiving a motion command from an input device, motion of a plurality of joints of a proximal repositionable structure of the repositionable assembly that pivots a distal portion of the proximal repositionable structure about a remote center of motion located at a first location relative to a workspace; determining, by the control system based on at least sensor signals indicative of physical configurations of the repositionable assembly, whether to command a reconfiguration of the proximal repositionable structure to move the distal portion relative to the workspace, such that a reachable space of a working portion of an instrument supported by a distal repositionable structure attached to the distal portion is moved relative to the workspace; and commanding, by the control system in response to a determination to command the reconfiguration, the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, such that the reachable space is moved relative to the workspace and the remote center of motion is maintained at the first location.

[0008] Consistent with some embodiments, one or more non-transitory machine-readable media include a plurality of machine-readable instructions which when executed by one or more processors are adapted to cause the one or more processors to perform any of the methods described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a diagram of a computer-assisted system in accordance with one or more embodiments.

[0010] Figure 2 illustrates a perspective view of working portions of instruments supported by a computer-assisted system in accordance with one or more embodiments.

[0011] Figure 3 is a block diagram of a control system for a computer-assisted system in accordance with one or more embodiments.

[0012] Figure 4 is a flow diagram of method steps for commanding reach assist motion of a computer-assisted system in accordance with one or more embodiments.

[0013] Figure 5 illustrates a configuration of a computer-assisted system in which a target in a workspace is located within reach of an instrument supported by the computer-assisted system in accordance with one or more embodiments.

[0014] Figure 6A illustrates a configuration of a computer-assisted system in which a target in a workspace is located at a depth that is deeper than an immediate range of motion of an instrument supported by the computer-assisted system in accordance with one or more embodiments.

[0015] Figure 6B illustrates a configuration of the computer-assisted system of Figure 6A after the computer-assisted system has been moved to adjust the reach of an instrument supported by the computer-assisted system in accordance with one or more embodiments.

[0016] Figure 7A illustrates a configuration of a computer-assisted system in which a target in a workspace is located at a depth that is deeper than an immediate range of motion of an instrument supported by the computer-assisted system in accordance with one or more embodiments.

[0017] Figure 7B illustrates a configuration of the computer-assisted system of Figure 7A after the computer-assisted system has been moved to adjust the reach of an instrument supported by the computer-assisted system in accordance with one or more embodiments.

[0018] In the figures, elements having the same designations have the same or similar functions.

DETAILED DESCRIPTION

[0019] In this description, specific details are set forth describing some embodiments consistent with the present disclosure. Numerous specific details are set forth in order to provide a thorough understanding of the embodiments. It will be apparent, however, to one skilled in the art that some embodiments may be practiced without some or all of these specific details. The specific embodiments disclosed herein are meant to be illustrative but not limiting. One skilled in the art may realize other elements that, although not specifically described here, are within the scope and the spirit of this disclosure. In addition, to avoid unnecessary repetition, one or more features shown and described in association with one embodiment may be incorporated into other embodiments unless specifically described otherwise or if the one or more features would make an embodiment non-functional.

[0020] Further, the terminology in this description is not intended to limit the invention. For example, spatially relative terms-such as “beneath”, “below”, “lower”, “above”, “upper”, “proximal”, “distal”, and the like-may be used to describe the relation of one element or feature to another element or feature as illustrated in the figures. These spatially relative terms are intended to encompass different positions (i.e., locations) and orientations (i.e., rotational placements) of the elements or their operation in addition to the position and orientation shown in the figures. For example, if the content of one of the figures is turned over, elements described as “below” or “beneath” other elements or features would then be “above” or “over” the other elements or features. A device may be otherwise oriented and the spatially relative descriptors used herein interpreted accordingly. Likewise, descriptions of movement along and around various axes include various special element positions and orientations. In addition, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context indicates otherwise. And, the terms “comprises”, “comprising”, “includes”, and the like specify the presence of stated features, steps, operations, elements, and/or components but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups. Components described as coupled may be electrically or mechanically directly coupled, or they may be indirectly coupled via one or more intermediate components.

[0021] Elements described in detail with reference to one embodiment, implementation, system, or module may, whenever practical, be included in other embodiments, implementations, systems, or modules in which they are not specifically shown or described. For example, if an element is described in detail with reference to one embodiment and is not described with reference to a second embodiment, the element may nevertheless be claimed as included in the second embodiment. Thus, to avoid unnecessary repetition in the following description, one or more elements shown and described in association with one embodiment, implementation, or application may be incorporated into other embodiments, implementations, or aspects unless specifically described otherwise, unless the one or more elements would make an embodiment or implementation non-functional, or unless two or more of the elements provide conflicting functions.

[0022] In some instances, well known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

[0023] This disclosure describes various devices, elements, and portions of computer- assisted systems and elements in terms of their state in three-dimensional space. As used herein, the term “position” refers to the location of an element or a portion of an element (e.g., three degrees of translational freedom in a three-dimensional space, such as along Cartesian x- , y-, and z-coordinates). As used herein, the term “orientation” refers to the rotational placement of an element or a portion of an element (e.g., three degrees of rotational freedom in three-dimensional space, such as about roll, pitch, and yaw axes, represented in angle-axis, rotation matrix, quaternion representation, and/or the like). As used herein, and for a device with a kinematic series, such as with a repositionable structure with a plurality of links coupled by one or more joints, the term “proximal” refers to a direction toward a base of the kinematic series, and “distal” refers to a direction away from the base along the kinematic series.

[0024] As used herein, the term “pose” refers to the multi-degree of freedom (DOF) spatial position and orientation of a coordinate system of interest attached to a rigid body. In general, a pose includes a pose variable for each of the DOFs in the pose. For example, a full 6-DOF pose for a rigid body in three-dimensional space would include 6 pose variables corresponding to the 3 positional DOFs x, y, and z) and the 3 orientational DOFs (e.g., roll, pitch, and

yaw). A 3-DOF position only pose would include only pose variables for the 3 positional DOFs. Similarly, a 3-DOF orientation only pose would include only pose variables for the 3 rotational DOFs. Further, a velocity of the pose captures the change in pose over time (e.g., a first derivative of the pose). For a full 6-DOF pose of a rigid body in three-dimensional space, the velocity would include 3 translational velocities and 3 rotational velocities. Poses with other numbers of DOFs would have a corresponding number of velocities translational and/or rotational velocities.

[0025] Aspects of this disclosure are described in reference to computer-assisted systems, which can include devices that are teleoperated, externally manipulated, autonomous, semiautonomous, and/or the like. Further, aspects of this disclosure are described in terms of an implementation using a teleoperated surgical system, such as the da Vinci® Surgical System commercialized by Intuitive Surgical, Inc. of Sunnyvale, California . Knowledgeable persons will understand, however, that inventive aspects disclosed herein may be embodied and implemented in various ways, including teleoperated and non-teleoperated, and medical and non-medical embodiments and implementations. Implementations using da Vinci® Surgical Systems are merely exemplary and are not to be considered as limiting the scope of the inventive aspects disclosed herein. For example, techniques described with reference to surgical instruments and surgical methods may be used in other contexts. Thus, the instruments, systems, and methods described herein may be used for humans, animals, portions of human or animal anatomy, industrial systems, general robotic, or teleoperated systems. As further examples, the instruments, systems, and methods described herein may be used for non-medical purposes including industrial uses, general robotic uses, sensing or manipulating non-tissue work pieces, cosmetic improvements, imaging of human or animal anatomy, gathering data from human or animal anatomy, setting up or taking down systems, training medical or non-medical personnel, and/or the like. Additional example applications include use for procedures on tissue removed from human or animal anatomies (with or without return to a human or animal anatomy) and for procedures on human or animal cadavers. Further, these techniques can also be used for medical treatment or diagnosis procedures that include, or do not include, surgical aspects.

[0026] Figure 1 is a diagram of a computer-assisted system 100 in accordance with one or more embodiments. The computer-assisted system 100 includes, in the example of Figure 1, a repositionable assembly 110 and a user input system 150. As will be described in more detail below, the user input system 150 includes one or more input controls, also referred to herein as input controls, for operating the repositionable assembly 110. An operator 198 can use the one or more input controls to command motion of the repositionable assembly 110, such as by commanding motion of the repositionable assembly 110, in a leader-follower configuration. The leader-follower configuration is a type of teleoperation configuration and is sometimes called a master-slave configuration in industry.

[0027] In some medical embodiments, the computer-assisted system 100 can be found in a clinic, diagnostic facility, an operating room, an interventional suite, or other medical environment. Although the computer-assisted system 100 is shown comprising one repositionable assembly 110 that supports a plurality of instruments 140, one of ordinary skill would understand that the computer-assisted system 100 can include any number of repositionable assemblies, where each repositionable assembly can comprise one or more repositionable structures and each repositionable structure can support one or more instruments, and that all of these elements can be similar or different in design from that specifically depicted in these figures. In some examples, each of the repositionable assemblies can include fewer or more repositionable structures, and/or support fewer or more instruments than specifically depicted in these figures.

[0028] In the example shown in Figure 1, the user input system 150 includes one or more input controls 152 configured to be operated by the operator 198. The one or more input controls 152 are contacted and manipulated by the hands of the operator 198, with one input control 152 for each hand. Examples of such hand-input-devices include any type of device manually operable by human user (e.g., joysticks, trackballs, button clusters, and/or other types of haptic devices typically equipped with multiple degrees of freedom). Position, force, and/or tactile feedback devices (not shown) can be employed to transmit position, force, and/or tactile sensations from instruments 140 supported on the repositionable assembly 110 back to the hands of the operator 198 through the input controls 152.

[0029] The input controls 152 are supported by the user input system 150 and are shown as mechanically grounded, and in other implementations can be mechanically ungrounded. An ergonomic support 156 can be provided in some implementations; for example, Figure 1 shows an ergonomic support 156 including forearm rests on which the operator 198 can rest his or her forearms while manipulating the input controls 152. In some examples, the operator 198 can perform tasks at a work site near the repositionable assembly 110 during a procedure by controlling the repositionable assembly 110 using the input controls 152. [0030] A display unit 154 is included in the user input system 150. The display unit 154 can display images for viewing by the operator 198. The display unit 154 can provide the operator 198 with a view of the worksite with which the repositionable assembly 110 interacts. The view can include stereoscopic images or three-dimensional images to provide a depth perception of the worksite and the instrum ent(s) of the repositionable assembly 110 in the workspace. The display unit 154 can be moved in various degrees of freedom to accommodate the viewing position of the operator 198 and/or to provide control functions. Where a display unit (such as the display unit 154) is also used to provide control functions, such as to command the repositionable assembly 110, the display unit also includes an input control (e.g„ another input control 152).

[0031] When using the user input system 150, the operator 198 can sit in a chair or other support, position his or her eyes to see images displayed by the display unit 154, grasp and manipulate the input controls 152, and rest his or her forearms on the ergonomic support 156 as desired. In some implementations, the operator 198 can stand at the station or assume other poses, and the display unit 154 and input controls 152 can differ in construction, be adjusted in position (height, depth, etc.), and/or the like.

[0032] The repositionable assembly 110 can be used to introduce one or more instruments 140 to a workspace through an entry guide 130 (e.g., a cannula, tube, or other similar fixture) inserted through an opening or port into the workspace, through a port component (not shown), or directly through an opening without using an entry guide, port, or other accessory. In a medical scenario, the workspace can be on or within a body of a patient, and the opening can be a minimally invasive incision or a natural body orifice. In some examples, the instruments 140 can include medical instruments or non-medical instruments. In some examples, the instruments 140 can include imaging devices and/or instruments with or without imaging devices. Examples of medical instruments include surgical instruments for interacting with tissue, imaging devices, sensing devices, and/or the like. In some examples, the instruments 140 can include end effectors that are capable of, but are not limited to, performing, gripping, retracting, cauterizing, ablating, suturing, cutting, stapling, fusing, sealing, etc., and/or combinations thereof.

[0033] When used, the entry guide 130 can be free-floating, held in place by a fixture separate from the repositionable assembly 110, or held by a linkage 128 or other part of the repositionable assembly 110. The linkage 122 can be coupled to additional joints and links 114, 120 of the repositionable assembly 110, and these additional joints and links 114, 120 can be mounted on a base 112. The linkage 122 can further include a manipulator-supporting link 124 located in a proximal direction 162 to the entry guide 130. A set of manipulators 126 located in the proximal direction 162 to the entry guide 130 can couple to the manipulatorsupporting link 124. The components of the repositionable assembly 110 that can be moved to follow commands from the user input system 150 can include one or more of any of the following: the linkage 122, additional joints and links 114, 120, base 112, manipulatorsupporting link 124, and/or any additional links or joints coupled to the foregoing joints or links. Each of the manipulators 126 can include a carriage (or other instrument-coupling link) configured to couple to an instrument 140, and each of the manipulators 126 can include one or more joint(s) and/or link(s) that can be driven to move the carriage. For example, a manipulator 126 can include a prismatic joint that, when driven, linearly moves the carriage and any instrument s) 140 coupled to the carriage. This linear motion can be along (parallel to) an insertion axis that extends in a distal direction 164 to and through the entry guide 130 and the opening into the workspace.

[0034] The additional joints and links 114, 120 can be used to position the entry guide 130 at the opening into the workspace or at another position. As shown in Figure 1, repositionable assembly 110 includes a prismatic joint for vertical adjustment (as indicated by arrow “A”) and a rotary joint for horizontal adjustment (as indicated by arrow “B”) that can be used to translate a position of the entry guide 130. The linkage 122 is used to pivot the entry guide 130 (and the instruments disposed within the entry guide) in yaw and pitch angular rotations about a remote center of motion (RCM) located in proximity to entry guide 130 as indicated by arrows D, E, and F, respectively, without translating the RCM.

[0035] Actuation of the degrees of freedom provided by joint(s) of the instrument s) 140 (not shown) can be provided by actuators disposed in, or whose motive force (e.g., linear force or rotary torque) is transmitted to, the instrument(s) 140. Examples of actuators include rotary motors, linear motors, solenoids, and/or the like. The actuators can drive transmission elements in the repositionable assembly 110 and/or in the instruments 140 to control the degrees of freedom of the instrument s) 140. For example, the actuators can drive rotary discs of the manipulator 126 that couple with drive elements (e.g., rotary discs, linear slides) of the instrum ent(s) 140, where driving the driving elements of the instruments 140 drives transmission elements in the instrument 140 that couple to move the joint(s) of the instrument 140, or to actuate some other function of the instrument 140, such as a degree of freedom of an end effector. Accordingly, the degrees of freedom of the instrument(s) 140 can be controlled by actuators that drive the instrum ent(s) 140 in accordance with control signals. The control signals can be determined to cause instrument motion or other actuation as determined automatically by the system, as indicated to be commanded by movement or other manipulation of the input controls, or any other control signal. Furthermore, appropriately positioned sensors (e.g., encoders, potentiometers, and/or the like) can be provided to enable measurement of indications of the joint positions, instrument positions, or other data that can be used to derive joint position, velocity, and so forth. The actuators and sensors can be disposed in, or transmit to, or receive signals from, the manipulate^ s) 126. Techniques for manipulating multiple instruments 140 in a computer-assisted system are described more fully in International Patent Publication No. WO 2022/0467787 entitled “METHOD AND SYSTEM FOR COORDINATED MULTIPLE-TOOL MOVEMENT USING A DRIVABLE ASSEMBLY,” which is incorporated herein by reference.

[0036] While a particular construction of the repositionable assembly 110 is shown in Figure 1, those skilled in the art will appreciate that embodiments of this disclosure can be used with any design of repositionable assembly or other repositionable structure. In some examples, a repositionable assembly can have any number and any types of degrees of freedom, can be configured to couple or not couple to an entry guide, and/or the like. In some examples, the repositionable assembly 110 can also include an arrangement of links and joints that does not provide a remote center of motion.

[0037] In some examples, embodiments of this disclosure can be used with systems that integrate a table with one or more repositionable, or manipulator assemblies that respectively support one or more instruments. In an example system, a table can include a movable tabletop that is supported by a table support structure that is mechanically grounded at a base. The example system further includes one or more repositionable assemblies that are supported by one or more respective support structures. The support structure(s) for the one or more repositionable assemblies can be mechanically grounded at the same base or at one or more respective different bases. In some examples, one or more of the repositionable assemblies included in the system are mechanically grounded on the floor near the table. In other examples, one or more of the repositionable assemblies are mechanically grounded at, or mounted to, a wall or a ceiling. In some examples, one or more of the repositionable assemblies are mechanically grounded to the table. For example, a repositionable assembly can be coupled to a tabletop or other portion of the table, such as the tabletop support structure or on a rail mounted to the table or the table top. In some examples, when a repositionable assembly is coupled to the table, the repositionable assembly moves in concert with and/or independently of the tabletop. Each of the table and the one or more repositionable assemblies can be controlled using the techniques described herein. In some examples, a system that integrates a table with a repositionable assembly can include one, two, three, four, five, or more individual manipulator assemblies that can be individually controlled. Furthermore, each of the one or more repositionable assemblies can support one or more respective instruments, such as the instruments described herein. Examples of such a multi-instrument surgical system architecture are the da Vinci Si® Surgical System and the da Vinci® Xi™ Surgical System, commercialized by Intuitive Surgical, Inc. Systems that integrate tables with repositionable or manipulator, assemblies are described more fully in International Patent Publication No. WO 2016/069648 entitled “SYSTEM AND METHOD FOR INTEGRATED SURGICAL TABLE,” which is incorporated herein by reference.

[0038] In the various embodiments described in this application, the repositionable assembly 110 comprises a proximal repositionable structure and one or more distal repositionable structures. In such examples, the proximal repositionable structure includes one or more of the above-described components of the repositionable assembly 110 and the one or more distal repositionable structures include one or more other above-described components of the repositionable assembly 110. Furthermore, the proximal repositionable structure has a distal portion onto which one or more distal repositionable structures can be mounted. Accordingly, in such examples, the distal portion of the proximal repositionable structure supports the base(s) of the distal repositionable structure(s), and motion of the distal portion of the proximal repositionable structure moves all distal repositionable structure(s) by moving all of the base(s) of the distal repositionable structure(s).

[0039] In one example architecture, the proximal repositionable structure can include one or more of the linkage 122, the additional joints and/or links 114, 120, the manipulatorsupporting link 124, and/or any additional links and/or joints coupled to the foregoing joints or links. In this example architecture, the one or more distal repositionable structures can include one or more of the manipulators 126, carriages (or other instrument-coupling links) configured to couple to instruments 140, and/or one or more joint(s) and/or link(s) that can be driven to move the carriages. The distal portion of the proximal repositionable structure onto which one or more distal repositionable structures are mounted can include the manipulator-supporting link 124. Accordingly, in this example architecture, the distal portion of the proximal repositionable structure (e.g„ the manipulator-supporting link 124) supports the base(s) of the distal repositionable structure(s) (e.g., the one or more manipulators 126), and motion of the distal portion of the proximal repositionable structure moves all the distal repositionable structure(s) and instruments 140 supported by the distal repositionable structure(s) by moving all of the base(s) of the distal repositionable structure(s).

[0040] Each distal repositionable structure is configured to support one or more of the instruments 140. The instruments 140 can be attached directly to the distal repositionable structure in some instances or be attached indirectly through one or more intervening adapters in other instances. During a procedure performed by the computer-assisted system 100, the instrument(s) 140 attached to a distal repositionable structure can be pivoted about a remote center of motion (RCM) associated with repositionable assembly 110 by commanding motion of the proximal repositionable structure to pivot the distal portion of the proximal repositionable structure about the RCM.

[0041] In some example architectures, the repositionable assembly 110 has a hardwarecentered RCM (HWC) or hardware remote center of motion and the repositionable assembly 110 is designed such that movement of a first set of drivable joints of the repositionable assembly 110 pivots a part of the proximal and/or distal repositionable structure (often a distal link or a distal portion) about the HWC. This HWC can be moved relative to the base 112 of the repositionable assembly 110 by actuating a second set of drivable joints of the repositionable assembly 110. In some examples, the drivable joints of the plurality of joints of the repositionable assembly 110 provide redundant degrees of freedom, and coordinated motion of the drivable joints can cause the part of the proximal and/or distal repositionable structure to pivot about a software-centered RCM (SWC). The location of the SWC can be moved relative to the base part of the proximal repositionable structure and/or distal repositionable structure(s) and is enabled by coordinated motion of the drivable joints. In some examples, the repositionable assembly 110 has an HWC and drivable joints that provide redundant degrees of freedom that enable the repositionable assembly 110 to pivot the part of the proximal and/or distal repositionable structure about a point other than the HWC and can switch between pivoting about an HWC or about a SWC. For a repositionable assembly that can switch between pivoting about an HWC and a SWC, the effective remote center is whatever point the commanded motions cause the part of the proximal and/or distal repositionable structure to pivot about.

[0042] When the repositionable assembly 110 performs a procedure, the RCM can be located at a suitable location, such as at an opening into a workspace (e.g., a port providing access to a chamber or a body, an incision, a natural orifice such as a mouth or throat, and/or the like). This RCM can be an HWC, or be a SWC for systems with HWCs and that can support SWCs, or be a SWC for systems without HWCs. Instruments 140 attached to the repositionable assembly 110, for example by being attached to one or more distal repositionable structures of the repositionable assembly 110, are pivoted about the RCM and articulated as the instruments 140 are used to perform tasks. The instruments 140 can be inserted or retracted relative to the workspace using the distal repositionable structure(s) and without moving the distal portion of the proximal repositionable structure. For example, the distal repositionable structure can have joints that can be driven and/or the instrument(s) 140 can have joints that can be driven, to insert the instrument(s) 140 further into the workspace, retract the instrum ent(s) 140 within or from the workspace, or articulate the instrum ent(s) 140 within the workspace. In an example, the joints of the instrument(s) 140 are driven by actuators directly, or by one or more transmission mechanisms of the distal repositionable structure(s) and/or the instrument that transmit force, torque, or motion (e.g., cables, gears, hypotubes, metal bands, pulleys, capstans, etc.).

[0043] Figure 2 illustrates a perspective view of working portions of instruments supported by a computer-assisted system in accordance with one or more embodiments. In the example of Figure 2, the instruments, such as the instruments 140 supported by one or more distal repositionable structures of repositionable assembly 110, include an imaging instrument 200 comprising an imaging device and non-imaging manipulation instruments 210, 220. The imaging instrument 200 shown is articulable, and the working portion can be moved relative to the shaft. The non-imaging manipulation instruments 210 and 220 shown are also articulable, and their working portions (jawed end effectors are shown) can also be moved relative to their shafts. Although instruments of particular designs are shown in Figure 2, other imaging instruments, manipulation instruments, or other instruments (e.g. suction, sensing, etc.) may have more, fewer, or no joints that can be driven to move the working ends relative to the shaft.

[0044] In the example shown, during operation, these instruments extend out from lumens within the entry guide 130 used with the repositionable assembly 110. The imaging device of the imaging instrument 200 includes optical stereo image capturing devices 202, 204, and an optical cable 206 (coupled at its proximal end to a light source) housed in its tip. The distal portions of the non-imaging manipulation instruments 210, 220 include respective working portions (e.g., end effectors) 212, 222. [0045] Each of the non-imaging manipulation instruments 210, 220 comprises a plurality of actuatable joints that can be driven by the distal repositionable structure(s) and a plurality of links coupled to the joints. As an example, the second non-imaging manipulation instrument 220 comprises first, second, and third links 224, 226, 228, first and second joints 232, 234, and a wrist joint 236. The first joint 232 couples the first and second links 224, 226 and the second joint 234 couples the second and third links 226, 228 so that the second link 226 can pivot about the first joint 232 in pitch and yaw while the first and third links 224, 228 remain parallel to each other. The first joint 232, second joint 234, and wrist joint 236 can also be driven by the distal repositionable structure(s) to insert and retract, via the first, second, and third links 224, 226, 228, the working portion 222 into and from the workspace in relative to the distal repositionable structure(s). The first non-imaging manipulation instrument 210 and the imaging instrument 200 can be operated similarly by the distal repositionable structure(s). In some examples, the instruments 140 supported by the repositionable assembly 110 are implemented as one or more of the first non-imaging manipulation instrument 210, the second non-imaging manipulation instrument 220, and/or the imaging instrument 200.

[0046] In some instances, during operation of the computer-assisted system 100, it is desirable to insert an instrument 140 further into a workspace than possible or retract the instrument in the workspace more than possible, when the distal portion of the proximal repositionable structure is maintained at the same distance relative to the workspace. For example, an operator 198 may desire to perform an action at a target within the workspace that is located at a distance further from the distal portion of the proximal repositionable structure than can be reached by an instrument 140 with the current configuration of the proximal repositionable structure. When a target within the workspace is located too deeply or too shallowly in the workspace so that the target cannot be reached by an instrument 140 coupled to a distal repositionable structure having a base that is located a fixed distance from the workspace, that target is considered to be located beyond the immediate range of motion (ROM) of the instrument 140. For example, a target outside the contactable range for an instrument (e.g„ the first or second non-imaging manipulation instrument 210, 220), when the base of the corresponding distal repositionable structure is located a fixed distance from the workspace is considered to be beyond the immediate range of motion of that instrument. The immediate range of motion the instrument 140 can be considered to be the reachable space of the working portion (often at a distal portion) of the instrument 140 without movement of the base of the distal repositionable structure supporting the instrument 140. When the instrument 140 is a non-imaging instrument, the working portion of the instrument can include one or more end effectors. When the instrument 140 is an imaging instrument, the working portion of the instrument can include one or more imaging devices. In some examples, the distal portion of the instrument 140 is the working portion of the instrument 140.

[0047] In some examples, immediate range of motion of an instrument 140 is limited by an insertion translation limit of the distal repositionable supporting the instrument 140. For example, a translation limit of the distal repositionable structure along an insertion axis of the instrument 140 can be a range of motion limit of the instrument 140. In various embodiments, the immediate ROM of the instrument 140 is determined by kinematic analysis of the instrument and the distal repositionable structure.

[0048] One potential approach for responding to an instance in which a target within the workspace is located beyond the immediate range of motion of an instrument 140 is to simply operate the repositionable assembly 110 with the limited instrument reach (e.g., range of motion of working portions of instruments). However, by operating the repositionable assembly 110 with limited instrument reach, the instrument 140 may be incapable of performing one or more tasks and/or operations on the target located beyond the immediate ROM of the instrument 140.

[0049] In another potential approach for responding to an instance in which a target within the workspace is located beyond the immediate range of motion of an instrument 140, the operator 198 can perform a manual procedure to adjust the physical configuration or positioning of the repositionable assembly 110 to obtain the desired reach for the instrument 140. However, this approach could be disruptive to a procedure being performed by the computer-assisted system 100, might require multiple adjustments to correctly configure or position the repositionable assembly 110, and/or increase the amount of time needed to perform a procedure.

[0050] Some embodiments of the disclosure include techniques for automatically or semi- automatically adjusting the reach of one or more instruments 140 (e.g., immediate range of motion of working portions of instruments 140) supported by distal repositionable structure(s) of the repositionable assembly 110. For example, the proximal repositionable structure includes drivable joints that are selectively driven (either automatically or semi-automatically) to move the distal portion of the proximal repositionable structure by a determined amount. The distal portion of the proximal repositionable structure can be moved along an insertion axis (e.g., for a predefined distance) in response to a determination that adjustment of the reach an instrument 140 is desirable. The determination that adjusting the reach of an instrument 140 is desirable can be made by considering one or more appropriate criteria, such as in response to one or more instruments 140 being at or near corresponding range of motion limit(s).

[0051] The insertion axis is an axis along which the distal portion of the proximal repositionable structure and/or a shaft of an instrument 140 supported by a distal repositionable structure is inserted and retracted relative to a workspace. In some examples, the insertion axis extends through the RCM of the repositionable assembly 110. In some examples, the insertion axis can be coincident with and/or parallel to one or more of a roll axis of the entry guide 130, a lumen extending through the entry guide 130, or a longitudinal axis of the entry guide 130.

[0052] In some instances, the techniques for automatically or semi-automatically adjusting the reach of one or more instruments 140 include defining a SWC to complement movement of the distal portion of the proximal repositionable structure such that the effective RCM of the repositionable assembly 110 is maintained relative to the workspace. For example, for instances in which the repositionable assembly 110 has an HWC, the HWC moves relative to the workspace when the distal portion of the repositionable structure is moved along the insertion axis, the techniques include defining the SWC. The SWC is defined at a location prior to movement of the distal portion of the proximal repositionable structure, to maintain the effective RCM of the repositionable assembly 110 relative to the workspace during movement of the distal portion of the proximal repositionable structure used to adjust the reach of one or more instruments 140. Thus, after the distal portion of the proximal repositionable structure is moved along the insertion axis, the instrument(s) 140 attached to the distal repositionable structure(s) can be pivoted about the SWC.

[0053] Figure 3 is a block diagram of a control system for a computer-assisted system (e.g., computer-assisted system 100) in accordance with one or more embodiments. As shown in the example of Figure 3, a control system 310 is coupled to the repositionable assembly 110 via an interface. Similarly, the control system is coupled to the user input system 150 via an interface. The interface(s) can be wired and/or wireless, and can include one or more cables, fibers, connectors, and/or buses and can further include one or more networks with one or more network switching and/or routing devices.

[0054] In one example, the repositionable assembly 110, the user input system 150, and/or the control system 310 can correspond to a patient side cart, a surgeon console, and the processing units and associated software of da Vinci® Surgical System commercialized by Intuitive Surgical, Inc. of Sunnyvale, California. In some embodiments, repositionable assemblies with other configurations, such as fewer or more repositionable structures, different user input systems or input controls, different repositionable structure hardware, and/or the like, can comprise the computer-assisted system 100.

[0055] In some embodiments, the control system 310 can be implemented as a stand-alone subsystem and/or board added to a computing device or as a virtual machine. In some embodiments, the repositionable assembly 110 is coupled to the user input system 150 via the control system 310. In some embodiments, the control system 310 can be included as part of the user input system 150 and/or the repositionable assembly 110. That is, in some embodiments, the control system 310 is integrated within the user input system 150 and/or the repositionable assembly 110. In some embodiments, the control system 310 can be operated separately from, and in coordination with, the user input system 150 and/or the repositionable assembly 110. In some embodiments, in response to a user inputting controls for operating the repositionable assembly 110 into the user input system 150, the user input system 150 provides the controls received from the user to the control system 310. The control system 310 then controls the repositionable assembly 110 with the controls received from the user input system 150.

[0056] Operation of the control system 310 is controlled by a processor system 320. The processor system 320 includes one or more central processing units, multi-core processors, microprocessors, microcontrollers, digital signal processors, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), graphics processing units (GPUs), tensor processing units (TPUs), and/or the like in the control system 310. The control system 310 further includes a memory 330 that is connected to the processor system 320. The memory 330 can be used to store software executed by the control system 310 and/or one or more data structures used during operation of the control system 310. The memory 330 can include one or more types of machine-readable media. Some common forms of machine- readable media can include floppy disk, flexible disk, hard disk, magnetic tape, any other magnetic medium, CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memory chip, or cartridge, and/or any other medium from which a processor or computer is adapted to read. [0057] As shown in the example of Figure 3, the memory 330 includes a reach assist control module 340 that can be used to support autonomous, semiautonomous, and/or teleoperated control of the repositionable assembly 110 and/or the instrument s) 140 during operation of computer-assisted system 100. The reach assist control module 340 includes one or more application programming interfaces (APIs) for receiving position, motion, force, torque, and/or other sensor information from components of repositionable assembly 110, such as the proximal repositionable structure, the one or more distal repositionable structures, and/or the instruments 140 supported by the one or more distal repositionable structures, for sharing position, motion, force, torque, and/or collision avoidance information with other control systems regarding other devices, and/or planning and/or assisting in the planning of motion for repositionable assembly 110 (such as motion of the proximal and one or more distal repositionable structures), and/or the instruments 140.

[0058] In some examples, the reach assist control module 340 is used to command automatic or semi-automatic movement of the distal portion of the proximal repositionable structure along the insertion axis to adjust the reach of one or more instruments 140 supported by distal repositionable structure(s) of the repositionable assembly 110, as described above. Such automatic or semi-automatic movement of the distal portion of the proximal repositionable structure along the insertion axis to extend the reach of an instrument 140 can hereinafter be referred to as “reach assist motion” of the distal portion of the proximal repositionable structure. More generally, the reach assist control module 340 commands reach assist motion of the distal portion of the proximal repositionable structure to reconfigure the pose of the proximal repositionable structure such that the reachable space (e.g„ immediate ROM) of instrument 140 is moved relative to the workspace. In the illustrated example of Figure 3, the reach assist control module 340 includes, without limitation, a velocity monitor 350, a depth monitor 360, and a command output module 370.

[0059] The velocity monitor 350 is used to monitor the velocity of the proximal repositionable structure. For example, using one or more sensors coupled to the repositionable assembly 110, or configured to detect the kinematic configuration of the repositionable assembly 110, the velocity monitor 350 determines the velocity of one or more degrees of freedom of the proximal repositionable structure due to the actuation of one or more joints of the proximal repositionable structure. In some examples, the reach assist control module 340 commands reach assist motion of the distal portion of the proximal repositionable structure in response to the velocity of one or more degrees of freedom of the proximal repositionable structure is non-zero. In some examples, the velocity monitor 350 is further used to monitor the velocity of other components, such as one or more distal repositionable structures or one or more instruments 140, included in and/or supported by the repositionable assembly 110. In some examples, the velocity monitor 350 is used to monitor the speed or velocity of the proximal repositionable structure and/or the speed or velocity of other components such as the one or more distal repositionable structures or one or more instruments 140.

[0060] The depth monitor 360 is used to monitor the “depth” of one or more instruments 140 supported by the distal repositionable structure(s) of the repositionable assembly 110. For example, using one or more sensors coupled to and/or external to the repositionable assembly 110, the depth monitor 360 determines the depth of an instrument 140. The “depth” of an instrument 140 is a measure of the distance of a distal end and/or working portion (e.g., a control point defined relative to the working portion) of the instrument 140 from a point of interest associated with the repositionable assembly 110. As examples, the depth of an instrument 140 can be determined as the distance of a distal end and/or a working portion of the instrument 140 from the HWC of the repositionable assembly 110, the distance of a distal end and/or a working portion of the instrument 140 from the SWC of the repositionable assembly 110, the distance of a distal end and/or a working portion of the instrument 140 from a distal end of the distal portion of the proximal repositionable structure, the distance of a distal end and/or working portion of the instrument 140 from an HWC or other portion of the entry guide 130, the distance of the distal end and/or working portion from a maximum insertion achievable by the distal end and/or working portion of the instrument 140 with the distal portion of the proximal repositionable structure held stationary, or (with a distal repositionable structure having a prismatic joint aligned with the insertion of instrument 140) the distance that prismatic joint position is from a full retracted prismatic joint. In some instances, the depth can be determined as a percentage or ratio or fraction. As an example, the depth is determined as a fraction having as numerator the distance the distal end and/or working portion of the instrument 140 is from a maximum retraction posture of the distal repositionable structure, and as a denominator a difference between maximum insertion and maximum retraction; in this example, zero would be no insertion, one would be maximum insertion, and higher values correspond with greater depths. As another example, and with a distal repositionable structure having a prismatic joint aligned with the insertion of instrument 140, the depth is determined as a percentage of the insertion range of motion remaining available for the prismatic joint, relative to the total insertion range of motion of the prismatic joint; in this example, a lower percentage corresponds to greater depth. [0061] The command output module 370 is used to determine and command motion of one or more of the proximal repositionable structure, one or more distal repositionable structures, and one or more instruments 140 supported by the one or more distal repositionable structures to perform the reach assist motion. In some examples, the reach assist motion is determined based on one or more of an instrument depth determined by the depth monitor 360, a velocity and/or a speed of a degree of freedom of the proximal repositionable structure determined by the velocity monitor 350, or some other sensor signal generated by a sensor assembly that is connected to and/or external to the repositionable assembly 110. For example, the command output module 370 determines a velocity, a speed, and/or a direction of motion for one or more of the proximal repositionable structure, one or more distal repositionable structures, and one or more instruments 140 supported by the one or more distal repositionable structures based on one or more of an instrument depth determined by the depth monitor 360, a velocity and/or speed of a degree of freedom of the proximal repositionable structure determined by the velocity monitor 350, or some other sensor signal generated by the one or more sensors coupled to and/or external to the repositionable assembly 110. Example sensors include joint encoders that provide joint state information (e.g., joint position joint velocity) that can be used along with known geometry of the repositionable structure(s) (e.g., dimensions, relationships between links and joints, etc.) to enable kinematic calculations for positions, velocities, speeds, accelerations, of portions of interest of the structure(s). Other examples of sensors include cameras that can provide images of the repositionable structure(s), and image processing of the image data from the cameras can be used in determining positions, velocities, accelerations, of portions of interest of the structure(s). The command output module 370 then commands motion of one or more of the proximal repositionable structure, one or more distal repositionable structures, and one or more instruments 140 supported by the one or more distal repositionable structures according to the determined velocity, speed, and/or direction for motion.

[0062] The command output module 370 is further used to determine and command motion of one or more components of the repositionable assembly 110 and/or instruments 140 supported by the repositionable assembly 110. In some examples, the command output module 370 determines and commands motion of the joints of one or more of the proximal repositionable structure, one or more distal repositionable structures, and/or one or more instruments 140 supported by the one or more distal repositionable structures in response to receiving commands from an input device, such as the user input system 150. In one specific example, the command output module 370 determines and commands motion of the plurality of joints that pivot the distal portion of the proximal repositionable structure about the RCM in response to receiving a motion command from the user input system 150. Hereinafter, operations performed by the depth monitor 360, the velocity monitor 350, and/or the command output module 370 can collectively be referred to as operations performed by the reach assist control module 340.

[0063] In some examples, the reach assist control module 340 determines whether to reconfigure the pose of the proximal repositionable structure based on the reach, or immediate range of motion, of one or more instruments 140. For example, the reach assist control module 340 can determine to maintain the current pose of the proximal repositionable structure when a target in the workspace is located within the reach of one or more instruments 140. In some examples, the reach assist control module 340 determines that a target is within reach of one or more instruments 140 when signals generated by the depth monitor 360 indicate that the operator is not moving the end effectors of one or more instruments 140 in an attempt to reach a target outside of the reachable space. As another example, the reach assist control module 340 can determine to modify, or reconfigure, the pose of the proximal repositionable structure when a target in the workspace is located beyond the reach of one or more instruments 140. In some examples, the reach assist control module 340 determines that a target is outside the reach of one or more instruments 140 when signals generated by the depth monitor 360 indicate that the operator is moving the end effectors of one or more instruments 140 to reach a target outside of an immediate range of motion of an instrument 140. In response to determining to reconfigure the pose of the proximal repositionable structure, the reach assist control module 340 commands, via the command output module 370, reach assist motion of the distal portion of the proximal repositionable structure to move the reachable space of an instrument 140.

[0064] In some instances, the reach assist control module 340 determines to reconfigure the pose of the proximal repositionable structure in response to the depth of an instrument 140, as determined by the depth monitor 360, being shallower than a minimum depth threshold. The minimum depth threshold can be, for example, determined based on a range of motion limit for further retracting the instrument 140 without moving the distal portion of the proximal repositionable structure. That is, the minimum depth threshold is determined based on a range of motion limit of the instrument 140 in the retraction, or proximal, direction when the distal portion of the proximal repositionable structure is fixed along an insertion axis relative to the workspace. [0065] In some examples, the minimum depth threshold is based on a defined fraction, or percentage, of the immediate full range of motion of the instrument 140, where 100% is the deepest point of the immediate range of motion of the instrument 140 and 0% is the shallowest point of the immediate range of motion of the instrument 140. In such examples, the minimum depth threshold is a value (e.g„ 20% (one-fifth), 25% (one-fourth), 30% (three-tenth), or some other percentage value or fraction) that is greater than 0% of the immediate range of motion of the instrument 140. In some examples, the minimum depth threshold is based on actual range of instrument depths. As an example, for some distal repositionable structures and/or instruments 140 used in general medical applications, the minimum depth threshold is between 3 and 4 cm, or between 6 and 8 cm, or between 8 cm and 10 cm from a shallowest depth in the immediate range of motion of the instrument 140. However, persons of ordinary skill will understand that the minimum depth threshold can have a different value than the examples provided herein.

[0066] In some instances, the reach assist control module 340 determines to reconfigure the pose of the proximal repositionable structure in response to the depth of an instrument 140 being deeper than a maximum depth threshold. The maximum depth threshold can be, for example, determined based on a range of motion limit for further extending the instrument 140 without moving the distal portion of the proximal repositionable structure. That is, the maximum depth threshold is determined based on a range of motion limit of the instrument 140 in the insertion, or distal, direction when the distal portion of the proximal repositionable structure is fixed along an insertion axis relative to the workspace.

[0067] In some examples, the maximum depth threshold is based on a defined fraction, or percentage, of the immediate full range of motion of the instrument 140, where 100% is the deepest point of the immediate range of motion of the instrument 140 and 0% is the shallowest point of the immediate range of motion of the instrument 140. In such examples, the maximum depth threshold is a value (e.g„ 80% (four-fifth), 75% (three-fourth), 70% (seven-tenth) or some other percentage value or fraction) that is less than 100% of the immediate range of motion of the instrument 140. In some examples, the maximum depth threshold is based on an actual range of instrument depths. As an example, for some distal repositionable structures and/or instruments 140 used in medical applications, the maximum depth threshold is between 20 and 35 cm, or 30 and 40 cm, or 40 and 50 cm, from a shallowest depth in the immediate range of motion of the instrument 140. However, persons of ordinary skill will understand that the maximum depth threshold can have a different value than the examples provided herein. [0068] In some examples, the minimum and maximum depth thresholds are determined based on one or more of an operator preference, a type of the instrument 140, the kinematic configuration of the instrument 140 (e.g„ the location of one or more joints of the instrument 140 relative to the entry guide 130 so as to keep the wrist joints of the instrument 140 distal to a lumen of the entry guide 130 through which the instrument 140 is inserted), or a pose of the proximal repositionable structure.

[0069] The maximum and minimum depth thresholds can be used to define different portions of the total range of motion. Example portions include less than the minimum threshold, more than the minimum threshold, between the minimum and maximum thresholds, more than the maximum threshold, less than the maximum threshold, and/or the like.

[0070] After, or in response to, determining to reconfigure the pose of the proximal repositionable structure to adjust the reach of an instrument 140, the reach assist control module 340 determines, via the command output module 370, which direction to command reach assist motion of the distal portion of the proximal repositionable structure along the insertion axis. In some examples, the reach assist control module 340 determines which direction to move the distal portion of the proximal repositionable structure in based on sensor signals that indicate a depth of the instrument 140 and/or a location of a target within the workspace. As an example, the reach assist control module 340 can determine to move the distal portion of the proximal repositionable structure along the insertion axis in the insertion direction in response to the sensor signals indicating that the operator may be attempting to reach a target that is located deeper in the workspace than an immediate range of motion limit of an instrument 140 (e.g., deeper than the maximum threshold of the immediate range of motion of the instrument 140). In another specific example, the reach assist control module 340 determines to move the distal portion of the proximal repositionable structure along the insertion axis in the retraction direction in response to the sensor signals or commanded motion indicating that the operator may be attempting to reach a target that is located shallower in the workspace than an immediate range of motion limit of an instrument 140 (e.g., shallower than the minimum threshold of the immediate range of motion of the instrument 140). The reach assist control module 340 then commands, via the command output module 370, reach assist motion of the distal portion of the proximal repositionable structure according to the determined direction of movement.

[0071] In some examples, the reach assist control module 340 enables reach assist motion of the distal portion of the proximal repositionable structure in a single direction relative to the workspace. For example, the reach assist control module 340 can enable reach assist motion of the distal portion of the proximal repositionable structure in only the insertion direction or in only the retraction direction. While the reach assist control module 340 enables reach assist motion of distal portion of the proximal repositionable structure in only the insertion direction, the reach assist control module 340 commands retraction of the distal portion of the proximal repositionable structure in response to commands to retract, such as those based on user input received, via the user input system 150, to retract the distal portion. Similarly, while the reach assist control module 340 enables reach assist motion of distal portion of the proximal repositionable structure in only the retraction direction, the reach assist control module 340 commands insertion of the distal portion of the proximal repositionable structure in response to commands to insert, such as those based on user input received, via the user input system 150, to insert the distal portion.

[0072] In some instances, the reach assist control module 340 restricts reach assist motion of the distal portion of the proximal repositionable structure along the insertion axis to time periods during joint(s) of the distal and/or proximal repositionable structure are already being driven for some other purpose. In such instances, the reach assist control module 340 enables and commands reach assist motion of the distal portion of the proximal repositionable structure in response to the movement, the speed, and/or the velocity, as determined by the velocity monitor 350, of one or more degrees of freedom of the distal and/or proximal repositionable structures being non-zero. Furthermore, in such instances, the reach assist control module 340 disables and prevents reach assist motion of the distal portion of the proximal repositionable structure in response to the speed or velocity, as determined by the velocity monitor 350, of each degree of freedom of the proximal repositionable structure being zero. In one example, the reach assist control module 340 enables and commands reach assist motion of the distal portion of the proximal repositionable structure in response to the distal portion of the repositionable structure pivoting the distal repositionable about the RCM and/or in response to the distal portion of the proximal repositionable structure already being relocated relative to the workspace. In another example, the reach assist control module 340 enables and commands reach assist motion of the distal portion of the proximal repositionable structure contemporaneously with other commanded motion, such as pitch, yaw, roll, insertion, and/or retraction, of the distal portion of the proximal repositionable structure. In another example, the reach assist control module 340 enables and commands reach assist motion of the distal portion of the proximal repositionable structure contemporaneously with actuation of one or more joints of the proximal repositionable structure, one or more joints of the instruments 140, and/or one or more joints of the distal repositionable structure(s) for an objective other than moving the distal portion.

[0073] In some examples, the reach assist control module 340 enables and commands reach assist motion of the distal portion of the proximal repositionable structure in response to the user input system 150 receiving a command to insert or retract an instrument 140 or the distal portion of the proximal repositionable structure. In some examples, the reach assist control module 340 enables and commands reach assist motion of the distal portion of the proximal repositionable structure in response to the reach assist control module 340 commanding an insertion or a retraction of an instrument 140 or the distal portion of the proximal repositionable structure.

[0074] After, or in response to, determining to reconfigure the pose of the proximal repositionable structure to adjust the reach of an instrument 140, the reach assist control module 340 determines, via the command output module 370, a speed or velocity for the reach assist motion of the distal portion of the proximal repositionable structure. In some examples, the reach assist control module 340 determines the speed or velocity of the reach assist motion of the distal portion of the proximal repositionable structure based on an actual or a commanded speed or velocity (such as a linear speed or velocity) of one or more of: a portion of the proximal repositionable structure, a portion of the distal repositionable structure, and/or a portion of an instrument 140 supported by the distal repositionable structure. In some examples, the reach assist control module 340 determines a speed or velocity (such as a linear speed or velocity) for the reach assist motion of the distal portion of the proximal repositionable structure based on an actual or commanded angular speed or velocity of the yaw, roll, and/or pitch of commanded motion of the distal portion of the proximal repositionable structure. In some instances, the reach assist control module 340 determines the speed or velocity of the reach assist motion by proportionally scaling based on the applicable, aforementioned, actual or commanded speed or velocity.

[0075] In some examples, the reach assist control module 340 scales the speed or velocity of the reach assist motion of the distal portion of the proximal repositionable structure based on a position of a distal end and/or an end effector of instrument 140 within the immediate ROM of the instrument 140, which can be determined by the depth monitor 360. In such examples, as the position of the distal end and/or end effector of the instrument 140 approaches an edge of an immediate range of motion limit, the reach assist control module 340 increases the speed of the reach assist motion of the distal portion of the proximal repositionable structure. As an example, the reach assist control module 340 can increase the speed or velocity of the reach assist motion of the distal portion of the proximal repositionable structure to a higher speed or velocity as the position of the distal end and/or end effector of an instrument 140 approaches the maximum depth threshold and/or the minimum depth threshold associated with the immediate ROM of the instrument 140. In some examples, as a position of a distal end and/or end effector of an instrument 140 moves towards the center of the immediate ROM of the instrument 140, the reach assist control module 340 decreases the speed or velocity of the reach assist motion of the distal portion of the proximal repositionable structure to a lower speed or velocity. In one specific example, the reach assist control module 340 decreases the speed or velocity of the reach assist motion of the distal portion of the proximal repositionable structure along the insertion axis to the lower speed or velocity as a position of a distal end and/or end effector of an instrument 140 moves away from the minimum and/or maximum depth thresholds towards the center of the immediate ROM of the instrument 140.

[0076] In some examples, after or in response to, determining to reconfigure the pose of the proximal repositionable structure to adjust the reachable space of an instrument 140, the reach assist control module 340 determines, via the command output module 370, an amount (e.g., a distance, a percentage amount, etc.) for the reach assist motion of the distal portion of the proximal repositionable structure. In some examples, the reach assist control module 340 determines the amount by which to move the distal portion of the proximal repositionable structure during reach assist motion based on a user commanded motion (e.g., an insertion command, a retraction command, etc.) received from the user input system 150. In some examples, the reach assist control module 340 determines the amount by which to move the distal portion of the proximal repositionable structure during reach assist motion based on a model of the workspace.

[0077] In some examples, the reach assist control module 340 commands, via the command output module 370, reach assist motion of the distal portion of the proximal repositionable structure to assist with insertion of an instrument 140. For example, the reach assist control module 340 can receive, via the user input system 150, a user command to insert an instrument 140 by a total amount. In this example, the reach assist control module 340 can command reach assist motion of the distal portion of the proximal repositionable structure in the insertion direction such that the instrument 140 is inserted by a first portion (e.g., 30%, 50%, etc.) of the total amount indicated by the user command. Furthermore, the reach assist control module 340 can then command motion of a degree of freedom of the instrument 140 and/or a degree of freedom of the distal repositionable structure that supports the instrument 140 to insert the instrument 140 by a second, or remaining portion, of the total amount indicated by the user command.

[0078] In some instances, when the reach assist control module 340 commands, via the command output module 370, reach assist motion of the distal portion of the proximal repositionable structure, the reach assist control module 340 determines and commands, via the command output module 370, further motion of the joints of the repositionable assembly 110 and/or an instrument 140 such that the combined motion that moves the distal portion of the proximal repositionable structure is within a null space of the working portion (e.g., null space of a tip of the end effector) of the instrument 140. That is, the reach assist control module 340 determines and commands contemporaneous movement of the distal repositionable structure(s) and/or the instrument 140 such that the distal end and/or working portion of the instrument 140 experiences no movement in the world reference frame (e.g., relative to the workspace) due to the reach assist motion being performed by the proximal repositionable structure. This contemporaneous movement of the distal repositionable structure(s) and/or the instrument 140 to prevent movement of the distal end of the instrument 140 during reach assist motion of the distal portion of the proximal repositionable structure can hereinafter be referred to as reach assist motion of the distal repositionable structure(s) and/or instrum ent(s) 140.

[0079] In an example in which the repositionable assembly 110 includes an HWC and drivable joints that provide redundant degrees of freedom, the reach assist control module 340 determines and commands, via the command output module 370, motion in the second set of drivable joints (the drivable joints that can move the HWC) in combination with corresponding motion of the instrument 140, the distal repositionable structures supporting the instrument 140, and/or a first set of drivable joints, such that the distal end and/or working portion of the instrument 140 experiences no movement during reach assist motion of the distal portion of the proximal repositionable structure. In this manner, the working portions of the instruments 140 (e.g., which may be at distal ends of the instruments) can remain stationary in the workspace relative to the world reference frame while the reachable space of the instruments 140 is improved relative to a target located in the workspace. For example, when the reach assist motion moves the distal portion of the proximal repositionable structure in the insertion direction, the contemporaneous movement of the distal repositionable structure and/or the instrument 140 causes the distal end and/or working portion of the instrument 140 to move in the proximal direction relative to the distal portion of the proximal repositionable structure so that the distal end and/or working portion does not move in either the insertion or retraction directions relative to the workspace.

[0080] In some examples, the command output module 370 matches a direction and/or a magnitude of the linear velocity of the reach assist motion of the proximal repositionable structure to the a direction and/or a magnitude of the linear velocity of the contemporaneous movement of the distal repositionable structure and/or the instrument 140. In some instances, the command output module 370 performs such matching by commanding the linear velocity of the reach assist motion of the proximal repositionable structure based on a commanded linear velocity of the distal repositionable structure and/or the instrument 140. In some instances, the command output module 370 performs such matching by commanding the linear velocity of the reach assist motion of the proximal repositionable structure based on a measured linear velocity of the distal repositionable structure and/or the instrument 140.

[0081] In some examples, the reach assist control module 340 applies one or more timedomain filters to smooth commands for reach assist motion of the distal portion of the proximal repositionable structure, reach assist motion of the distal repositionable structures, and/or reach assist motion of the instruments 140.

[0082] In some embodiments, the reach assist control module 340 is further used to set and maintain a position of a SWC during reach assist motion of the distal portion of the proximal repositionable structure. For examples in which the repositionable assembly 110 has an HWC, the HWC moves relative to the workspace during reach assist motion of the distal portion of the proximal repositionable structure. Thus, in such examples, the reach assist control module 340 records a location of a RCM (e.g., the HWC or a previously set SWC) for the repositionable assembly 110 before reach assist motion of the distal portion of the proximal repositionable structure and maintains the recorded location of as effective RCM of the repositionable assembly 110 during and after reach assist motion of the distal portion of the proximal repositionable structure. In some examples, the reach assist control module 340 sets the location of the SWC to be a location at or near an entry into the workspace before reach assist motion of the distal portion of the proximal repositionable structure. During and after the reach assist motion of the distal portion of the proximal repositionable structure is completed, the reach assist control module 340 pivots the instruments 140 about the SWC during operation of the computer-assisted system 100. [0083] In some embodiments, the reach assist control module 340 considers the depths of one or more other instruments 140, as determined by the depth monitor 360, before determining whether to command reach assist motion of the distal portion of the proximal repositionable structure to adjust the reachable space of a particular instrument 140. In some instances, the reach assist control module 340 further considers the insertion depths of one or more other instruments 140, as determined by the depth monitor 360, before determining whether to command reach assist motion of the distal repositionable structures and/or a particular instrument 140.

[0084] In some examples, in response to the depth of a distal end and/or working portion of a particular instrument 140 being deeper than a maximum depth threshold of the immediate range of motion of the particular instrument 140, the reach assist control module 340 enables and commands, via the command output module 370, reach assist motion of one or more of the distal portion of the proximal repositionable structure, the distal repositionable structures, and/or an instrument 140 if all other instruments 140 supported by the distal repositionable structures have respective depths that are deeper than a minimum insertion depth. In such examples, if the depth of one or more of the other instruments 140 is shallower than a minimum insertion depth, the reach assist control module 340 disables reach assist motion. In some examples, in response to the depth of a distal end and/or working portion of a particular instrument 140 being deeper than a maximum depth threshold of the particular instrument 140, the reach assist control module 340 enables and commands, via the command output module 370, reach assist motion. Depending on the physical architecture of the repositionable assembly, the reach assist motion can be of the distal portion of the proximal repositionable structure, and/or the distal portions of multiple distal repositionable structures, and/or an instrument 140. In some instances, a further movement condition is applied, such that the reach assist motion is performed if all non-imaging instruments included in the instruments 140 supported by the distal repositionable structures have respective depths that are deeper than respective minimum insertion depths.

[0085] In some examples, to adjust the reachable space of a particular instrument 140, the reach assist control module 340 enables and commands, via the command output module 370, reach assist motion of one or more of the distal portion of the proximal repositionable structure, the distal repositionable structures, and/or an instrument 140 if all other instruments 140 supported by the distal repositionable structures have respective depths that are shallower than a maximum insertion depth. In this specific example, if the depth of one or more of the other instruments 140 is deeper than a maximum insertion depth, the reach assist control module 340 disables reach assist motion. In some examples, in response to the depth of a distal end and/or working portion of the particular instrument 140 being deeper than a maximum depth threshold of the particular instrument 140, the reach assist control module enables and commands, via the command output module 370 reach assist motion. Depending on the physical architecture of the repositionable assembly, the reach assist motion can be of the distal portion of the proximal repositionable structure, and/or the distal portions of multiple distal repositionable structures, and/or an instrument 140. In some instances, a further movement condition is applied, such that the reach assist motion is performed if all nonimaging instruments included in the instrument 140 supported by the distal repositionable structures have respective depths that are shallower than respective maximum insertion depths.

[0086] to adjust the reachable space of a particular instrument 140, the reach assist control module 340 enables and commands, via the command output module 370, reach assist motion of one or more of the distal portion of the proximal repositionable structure, the distal repositionable structures, and/or an instrument 140 if all non-imaging instruments included in the instruments 140 supported by the distal repositionable structures have respective depths that are shallower than a maximum insertion depth.

[0087] In some examples, to determine whether to reconfigure the pose of the proximal repositionable structure, the reach assist control module 340 determines both whether to move the reachable space of an instrument 140 and whether one or more movement conditions are satisfied. For example, as described above, the reach assist control module 340 can determine to move the reachable space of an instrument 140: when sensor signals or commanded motion provide an indication that (i) an operator is attempting to reach a target in the workspace that is located outside of the reachable space of the instrument 140, (ii) a depth of the working portion of the instrument 140 is deeper than a range of motion limit (e.g„ maximum depth threshold), (iii) a depth of the working portion of the instrument 140 is shallower than a range of motion limit minimum depth threshold), (iv) the depth of the working portion of the

instrument 140 is within a fraction amount or threshold of a range of motion limit, (v) a joint of the distal repositionable structure is within a threshold of a range of motion limit of the joint, (vi) a motion commanded by an operator exceeds the range of motion limit of the joint.

[0088] In some examples, the reach assist control module 340 limits the range of allowable reach assist motion of the distal portion of the proximal repositionable structure, the distal repositionable structures, and/or the instruments 140 based on a model of the workspace. For example, the reach assist control module 340 limits the range of allowable reach assist motion based on a model of the workspace so as to prevent unwanted collisions and/or other interactions between one or more instruments 140 and/or material in the workspace. In a medical example, the reach assist control module 340 limits the range of allowable reach assist motion based on a model of a patient anatomy. In some instances, the reach assist control module 340 limits the range of allowable reach assist motion based on user defined depths limits of an instrument 140. The user defined depth limits can be defined, for example, by using the user input system 150, by using a user-interface of a touchpad, by using an instrument as a probe to physically map the depth limits, and/or using any other technically feasible approach.

[0089] In some embodiments, the reach assist control module 340 disables reach assist motion in response to one or more conditions being met. In some examples, the reach assist control module 340 disables reach assist motion of one or more of the distal portion of the proximal repositionable structure, the distal repositionable structures, and/or the instruments 140 in response to a range of motion limit of one or more joints of the repositionable assembly 110 being reached. In some examples, the reach assist control module 340 disables reach assist motion of one or more of the distal portion of the proximal repositionable structure, the distal repositionable structures, and/or the instruments 140 in response to determining that a collision between an instrument 140 and material in the workspace is anticipated or detected. In some examples, the reach assist control module 340 detects collisions between an instrument 140 and material in the workspace. In some embodiments, the collision is detected using a camera or other imaging device separate from the repositionable structures, a depth mapping sensor, some other sensor (e.g., contact, pressure, or force sensors), and/or the like. In some examples, the reach assist control module 340 anticipates collisions between an instrument 140 and material in the workspace based on a user setting (e.g., a user-configured SWC depth) and/or based on geometries of system components (e.g., the shape and/or size of an entry guide through which instruments 140 are introduced into a workspace).

[0090] In some embodiments, reach assist motion of one or more of the distal portion of the proximal repositionable structure, the distal repositionable structures, or the instruments 140 can be user-activated and/or the control system 310 prompts the user to approve reach assist motion before performing the reach assist motion. For example, a user can activate reach assist motion and/or approach reach assist motion requests using the user input system 150, an input device (e.g., a button, a pedal, a lever, a pressure sensor, etc.), a user interface, a voice command, or a gesture. In some embodiments, reach assist motion of one or more of the distal portion of the proximal repositionable structure, the distal repositionable structures, or the instruments 140 is only enabled during particular operating modes of the computer-assisted system 100. For example, reach assist motion of one or more of the distal portion of the proximal repositionable structure, the distal repositionable structures, or the instruments 140 is enabled during an operating mode of computer-assisted system 100 for adjusting a pose of the repositionable assembly 110. As another example, reach assist motion of one or more of the distal portion of the proximal repositionable structure, the distal repositionable structures, or the instruments 140 is enabled during an operating mode of computer-assisted system 100 for teleoperation of the repositionable assembly 110.

[0091] Figure 4 is a flow diagram of method steps for commanding reach assist motion of a computer-assisted system in accordance with one or more embodiments. Although the method steps are described in conjunction with the systems of Figures 1-3 and the examples of Figures 5-7B, persons of ordinary skill will understand that any system configured to perform the method steps, in any order, is within the scope of the present disclosure. One or more of the processes 402-408 of method 400 can be implemented, at least in part, in the form of executable code stored on non-transient, tangible, machine-readable media. This executable code, when executed by a processor system the processor system 320 in the control

system 310), can cause the processor system to perform one or more of the processes 402-408. In some embodiments, method 400 can be performed by a module, such as the reach assist control module 340. In some embodiments, method 400 can be applied to one or more proximal repositionable structures of the repositionable assembly 110 included in the computer-assisted system 100. Aspects of method 400 are described with reference to Figures 5-7B as described in further detail below. However, it is understood that the examples of Figure 5, Figures 6A and 6B, and Figures 7A and 7B are not restrictive, and that other values, shapes, behaviors, and/or the like depicted in Figure 5, Figures 6A and 6B, and Figures 7A and 7B may be different for different input controls 152, different repositionable structures, different follower instruments, different DOFs, different procedures, different viewable objects, and/or the like.

[0092] At a process 402, a control module, such as the reach assist control module 340, receives a motion command from an input device, such as the user input system 150. The reach assist control module 340 can receive the motion command via any technically feasibly techniques, such as by detecting an input from one or more input controls 152, in response to being manipulated by the operator 198, receiving an input from a semi-autonomous or autonomous software application executed by the processor system (e.g., the processor system 320 in the control system 310), and/or the like.

[0093] At a process 404, in response to receiving the motion command, the control module commands motion of a plurality of joints that pivots the distal portion of the proximal repositionable structure about a remote center of motion located at a first location relative to a workspace. For example, the reach assist control module 340 commands, via the command output module 370, motion of the first set of drivable joints of the repositionable assembly 110 to pivot the distal portion of the proximal repositionable structure about an RCM located at a first location relative to a workspace. In one example, the RCM is a SWC. In other examples, the RCM is an HWC. In further examples, the RCM is sometimes a SWC and sometimes an HWC.

[0094] At a process 406, the control module determines, based on one or more sensor signals, whether to command a reconfiguration of the proximal repositionable structure to move the distal portion of the proximal repositionable structure relative to the workspace, such that the reachable space is moved relative to the workspace. For example, the reach assist control module 340 determines to command a reconfiguration of the proximal repositionable structure relative to the workspace in response to the one or more sensor signals (e.g., signals generated by the depth monitor 360) indicating that the operator is moving the end effectors of the instruments 140 to reach a target in the workspace that is located outside of the reachable space (e.g., immediate ROM) of an instrument 140. In some examples, the reach assist control module 340 determines to command a reconfiguration of the proximal repositionable structure relative to the workspace in response to the one or more sensor signals (e.g., sensor signals generated by the depth monitor 360 and the velocity monitor 350) indicating that the operator is attempting to reach a target in the workspace that is located outside of the reachable space of an instrument 140 and movement, the speed or the velocity of one or more degrees of freedom of the proximal repositionable structure, as determined by the velocity monitor 350, is nonzero. In some examples, the sensor signals indicate one or more of a depth of an instrument 140, a reachable space (e.g., immediate ROM) of an instrument 140, whether an operator is attempting to move the working portions of the instrument 140 to reach a target located outside of the reachable space of an instrument 140, the speed or velocity of one or more degrees of freedom of the proximal repositionable structure and/or the distal repositionable structure, or some other parameter of the computer-assisted system 100. [0095] In some examples, to determine whether to command the reconfiguration of the proximal repositionable structure, the control module determines whether to move the reachable space of an instrument and determines whether one or more movement conditions are satisfied. For example, the reach assist control module 340 can determine to move the reachable space of an instrument 140 in response to the sensor signals or commanded motion indicating that the operator is attempting to reach a target in the workspace that is located outside of the reachable space of the instrument 140. In some examples, the one or more movement conditions include the receipt, via user input system 150, of a user command. As an example, the user command could be a command for motion of the repositionable assembly 110 and/or of an instrument 140. As another example, the user command could be a command to enter an operation mode for adjusting a pose of the repositionable assembly 110. In some examples, the one or move movement conditions include the performance of a command for motion, the computer-assisted system 100 entering or being in a particular operating mode. For example, the particular operating mode code by a mode for adjusting a pose of the repositionable assembly 110 or a teleoperation mode. In some examples, the one or more movement conditions include detection, by velocity monitor 350, of movement of at least one joint of the plurality of joints included in the repositionable assembly 110. In some examples, the one or more movement conditions include one or more of a receipt, via user input system 150, of a user command for motion of the proximal repositionable structure, performance by the proximal repositionable structure of a user commanded motion, and/or a detection, via velocity monitor 350, of movement, non-zero speed, and/or non-zero velocity of at least one degree of freedom of the proximal repositionable structure. In some examples, the one or more movement conditions can include one or more of a receipt, via user input system 150, of a user command for an insertion of an instrument 140 and/or a performance by the repositionable assembly 110 of the user command for the insertion of an instrument 140.

[0096] In that regard, Figure 5 illustrates a configuration of a computer-assisted system in which a target in a workspace is located within reach of an instrument supported by the computer-assisted system in accordance with one or more embodiments. In the example of Figure 5, a configuration 500 of the computer-assisted system 100 is shown. While posed in the configuration 500, the proximal repositionable structure of the computer-assisted system 100 is positioned such that an HWC 502 of the computer-assisted system 100 is located near an opening 504 into a workspace 506. In some examples, the HWC 502 corresponds to a specific portion of the entry guide 130 when the entry guide is attached to a distal repositionable structure a manipulator 126) as indicated by the dark stripe on the entry

guide 130. In this example, a SWC 508 has also been set, for example by the reach assist control module 340, at a first location proximate an opening 504 into the workspace 506 and/or proximate the HWC 502.

[0097] As further shown in Figure 5, while the computer-assisted system 100 is posed in the configuration 500, a target 510 in the workspace 506 is located within the reachable space, or immediate range of motion 512, of an instrument 140 extending out of the entry guide 130 into the workspace 506. For example, the target 510 is located at a depth along the insertion axis 514 that is between the minimum and maximum depth thresholds 516, 518 of the immediate ROM 512 of the instrument 140. Accordingly, with respect to the configuration 500 of the computer-assisted system 100 shown in Figure 5, because the sensor signals or commanded motion indicate that the operator is not moving the working portions of the instruments 140 to reach a target that is located outside of the immediate ROM 512 of the instrument 140, the reach assist control module 340 determines not to command a reconfiguration of the proximal repositionable structure to move the distal portion of the proximal repositionable structure relative to the workspace 506 at process 406. Thus, in this example, method 400 returns to process 402.

[0098] As another example, Figure 6A illustrates a configuration of a computer-assisted system in which a target in a workspace is located at a depth that is deeper than an immediate range of motion of an instrument supported by the computer-assisted system in accordance with one or more embodiments. In the example of Figure 6A, a configuration 600A of the computer-assisted system 100 is shown. While posed in the configuration 600A, the proximal repositionable structure of the computer-assisted system 100 is positioned such that an HWC 602 of the computer-assisted system 100 is located near an opening 604 into a workspace 606. In some examples, the HWC 602 corresponds to a specific portion of the entry guide 130 when the entry guide 130 is attached to a distal repositionable structure (e.g., a manipulator 126) as indicated by a dark stripe on the entry guide 130. In this example, a SWC 608 has also been set, for example by the reach assist control module 340, at a first location proximate an opening 604 into the workspace 606 and/or proximate the HWC 602.

[0099] As further shown in Figure 6A, while the computer-assisted system 100 is posed in the configuration 600A, a target 610 in the workspace 606 is located outside of the reachable space, or immediate range of motion 612A, of an instrument 140 extending out of the entry guide 130 into the workspace 606. For example, the target 610 is located at a depth along the insertion axis 614 that is deeper than the maximum depth threshold 618A of the immediate ROM 612A of the instrument 140. Accordingly, with respect to the configuration 600A shown in Figure 6A, because the sensor signals or commanded motion indicate that the operator is attempting to move the working portions of the instruments 140 to reach a target that is located outside of the immediate ROM 612A of the instrument 140, the reach assist control module 340 determines to command a reconfiguration of the proximal repositionable structure to move the distal portion of the proximal repositionable structure relative to the workspace 606 at process 406. In particular, because the sensor signals or commanded motion indicate that the operator is attempting to move the working portions of the instruments 140 to reach a target that is located at a depth along the insertion axis 614 that is deeper than the immediate ROM 612A of the instrument 140, the reach assist control module 340 determines to command a reconfiguration of the proximal repositionable structure to move the distal portion of the proximal repositionable structure in the insertion direction along the insertion axis 614 at process 406. The method 400 then proceeds to process 408.

[0100] As another example, Figure 7A illustrates a configuration of a computer-assisted system in which a target in a workspace is located within reach of an instrument supported by the computer-assisted system in accordance with one or more embodiments. In the example of Figure 7A, a configuration 700A of the computer-assisted system 100 is shown. While posed in the configuration 700A, the proximal repositionable structure of the computer-assisted system 100 is positioned such that an HWC 702 of the computer-assisted system 100 is located near an opening 704 into a workspace 706. In some examples, the HWC 702 corresponds to a specific portion of the entry guide 130 when the entry guide is attached to a distal repositionable structure (e.g., a manipulator 126) as indicated by the dark stripe on the entry guide 130. In this example, a SWC 708 has also been set, for example by the reach assist control module 340, at a first location proximate an opening 704 into the workspace 706 and/or proximate the HWC 702.

[0101] As further shown in Figure 7A, while the computer-assisted system 100 is posed in the configuration 700A, a target 710 in the workspace 706 is located outside of the reachable space, or immediate range of motion 712A, of an instrument 140 extending out of the entry guide 130 into the workspace 706. For example, the target 710 is located at a depth along the insertion axis 714 that is shallower than the minimum depth threshold 716A of the immediate ROM 712A of the instrument 140. Accordingly, with respect to the configuration 700A shown in Figure 7A, because the sensor signals or commanded motion indicate that the operator is attempting to move the working portions of the instruments 140 to reach a target that is located outside of the immediate ROM 712A of the instrument 140, the reach assist control module 340 determines to command a reconfiguration of the proximal repositionable structure to move the distal portion of the proximal repositionable structure relative to the workspace 706 at process 406. In particular, because the sensor signals or commanded motion indicate that the operator is attempting to move the working portions of the instruments 140 to reach a target that is located at a depth along the insertion axis 714 that is shallower than the immediate ROM 712A of the instrument 140, the reach assist control module 340 determines to command a reconfiguration of the proximal repositionable structure to move the distal portion of the proximal repositionable structure in the retraction direction along the insertion axis 714 at process 406. The method 400 then proceeds to process 408.

[0102] At a process 408, the control module commands, in response to a determination to command the reconfiguration, the proximal repositionable structure to move the distal portion of the proximal repositionable structure relative to the workspace while relocating the remote center of motion relative to the distal portion of the proximal repositionable structure, such that the reachable space of the instrument is moved relative to the workspace and the remote center of motion is maintained at the first location. For example, the reach assist control module 340 commands, via the command output module 370, the proximal repositionable structure to move the distal portion of the proximal repositionable structure along the insertion axis to adjust the reachable space of the instrument 140. As the distal portion of the proximal repositionable structure moves along the insertion axis, the reach assist control module 340 also relocates the RCM relative to the distal portion of the proximal repositionable such that the RCM is maintained at the first location relative to a world reference frame. That is, the reach assist control module 340 does not move the location of the RCM as the distal portion of the proximal repositionable structure moves along the insertion axis. The location of the RCM does, however, move relative to the distal portion of the proximal repositionable structure. In some examples, the reach assist control module 340 updates the location of the RCM relative to the distal portion of the proximal repositionable structure. In some examples, relocating the RCM relative to the distal portion of the proximal repositionable structure includes setting a SWC at a location that is different than a location of an HWC.

[0103] In some examples, the reach assist control module 340 commands, via the command output module 370, the proximal repositionable structure to move the distal portion of the proximal repositionable structure in the insertion direction along the insertion axis in response to the sensor signals or commanded motion indicating that an operator is moving the working portions of the instruments 140 to reach a target in the workspace that is located at a depth along the insertion axis that is deeper than the reachable space of the instrument 140. In some examples, the reach assist control module 340 commands, via the command output module 370, the proximal repositionable structure to move the distal portion of the proximal repositionable structure in the retraction direction along the insertion axis in response to the sensor signals or commanded motion indicating that an operator is moving the working portions of the instruments 140 to reach a target in the workspace that is located at a depth along the insertion axis that is shallower than the reachable space of the instrument 140. In some examples, the reach assist control module 340 commands, via the command output module 370, the proximal repositionable structure to move the distal portion of the proximal repositionable structure in the retraction direction along the insertion axis in response to the operator commanding the working portions of the instruments 140 to reach a target in the workspace that is located at a depth along the insertion axis that is shallower than the reachable space of the instrument 140.

[0104] In some examples, the reach assist control module 340 module further commands, via the command output module 370, motion of the distal repositionable structure and/or the instrument 140 such that the distal end and/or working portion of the instrument 140 experiences no movement relative to the workspace as the distal portion of the proximal repositionable structure is moved along the insertion axis. For example, the reach assist control module 340 can command motion of the distal repositionable structure and/or the instrument 140 to move the distal end and/or working portion of the instrument 140 in the retraction direction in response to the distal portion of the proximal repositionable structure being moved in the insertion direction, such that the distal end and/or working portion of the instrument 140 experiences no movement relative to the workspace. As another example, the reach assist control module 340 can command motion of the distal repositionable structure and/or the instrument 140 to move the distal end and/or working portion of the instrument 140 in the insertion direction in response to the distal portion of the proximal repositionable structure being moved in the retraction direction, such that the distal end and/or working portion of the instrument 140 experiences no movement relative to the workspace.

[0105] Figure 6B illustrates a configuration of the computer-assisted system after the computer-assisted system of Figure 6A has been moved to adjust the reachable space of an instrument supported by the computer-assisted system in accordance with one or more embodiments. In particular, Figure 6B illustrates a configuration 600B of the computer- assisted system 100 that results from moving the distal portion of the proximal repositionable structure from its pose in the configuration 600A to a pose that adjusts the reachable space of the instrument 140. When compared to the configuration 600A, the HWC 602 has moved in the insertion direction relative to the workspace 606 when the computer-assisted system 100 is posed in the configuration 600B. Importantly, however, the SWC 608 remains at the first location proximate the opening 604 into the workspace 606 when the computer-assisted system 100 is posed in the configuration 600B. That is, while moving the distal portion of the proximal repositionable structure at process 408, the reach assist control module 340 relocates the SWC 608 relative to the distal portion of the proximal repositionable structure such that the position of the SWC 608 is maintained at the first location proximate the opening 604 into the workspace 606.

[0106] As further shown in Figure 6B, when the computer-assisted system 100 is posed in the configuration 600B, the reachable space, or immediate ROM 612B, of the instrument 140 has been moved relative to the reachable space, or immediate ROM 612A, of the instrument 140 when the computer-assisted system was posed in the configuration 600A. In this example, when compared to the immediate ROM 612A of the instrument 140, the immediate ROM 612B of the instrument 140 has been moved along the insertion axis 614 in the insertion direction such that the target 610 is now located within the immediate ROM 612B of the instrument 140. For example, the target 610 is now located at a depth along the insertion axis 614 such that the target 610 is located between the minimum and maximum depth thresholds 616B, 618B of the immediate ROM 612B of the instrument 140.

[0107] As further shown in Figure 6B, the distal end and/or working portion of the instrument 140 was not moved relative to the target 610 in the workspace 606 during movement of the distal portion of the repositionable structure in the insertion direction along the insertion axis 614. The distal end and/or working portion of the instrument 140 did not move relative to the target 610 in the workspace 606 because, while commanding motion of the proximal repositionable structure to move the distal portion of the proximal repositionable structure in the insertion direction, the reach assist control module 340 further commanded contemporaneous motion of the distal repositionable structure and/or the instrument 140 to move the distal end and/or working portion of the instrument 140 in the retraction direction.

[0108] Figure 7B illustrates a configuration of the computer-assisted system after the computer-assisted system of Figure 7A has been moved to adjust the reachable space of an instrument supported by the computer-assisted system in accordance with one or more embodiments. In particular, Figure 7B illustrates a configuration 700B of the computer- assisted system 100 that results from moving the distal portion of the proximal repositionable structure from its pose in the configuration 700A to a pose that adjusts the reachable space of the instrument 140. When compared to the configuration 700A, the HWC 702 has moved in the retraction direction relative to the workspace 706 when the computer-assisted system 100 is posed in the configuration 700B. Importantly, however, the SWC 708 remains at the first location proximate the opening 704 into the workspace 706 when the computer-assisted system 100 is posed in the configuration 700B. That is, while moving the distal portion of the proximal repositionable structure at process 408, the reach assist control module 340 relocated the SWC 708 relative to the distal portion of the proximal repositionable structure such that the position of the SWC 708 is maintained at the first location proximate the opening 704 into the workspace 706.

[0109] As further shown in Figure 7B, when the computer-assisted system 100 is posed in the configuration 700B, the reachable space, or immediate ROM 712B, of the instrument 140 has been moved relative to reachable space, or immediate ROM 712A, of the instrument 140 when the computer-assisted system 100 was posed in the configuration 700A. In this example, when compared to the immediate ROM 712A of the instrument 140, the immediate ROM 712B of the instrument 140 has been moved along the insertion axis 714 in the retraction direction such that the target 710 is now located within the immediate ROM 712B of the instrument 140. For example, the target 710 is now located at a depth along the insertion axis 714 such that the target 710 is located between the minimum and maximum depth thresholds 716B, 718B of the immediate ROM 712B of the instrument 140.

[0110] As further shown in Figure 7B, the distal end and/or end effector of the instrument 140 was not moved relative to the target 710 in the workspace 706 during movement of the distal portion of the repositionable structure in the retraction direction along the insertion axis 714. The distal end and/or working portion of the instrument 140 did not move relative to the target 710 in the workspace 706 because, while commanding motion of the proximal repositionable structure to move the distal portion of the proximal repositionable structure in the retraction direction, the reach assist control module 340 further commanded contemporaneous motion of the distal repositionable structure and/or the instrument 140 to move the distal end and/or working portion of the instrument 140 in the insertion direction.

[OHl] After process 408, the method 400 then returns to process 402 where the control module, such as the reach assist control module 340, optionally receives another motion command from an input device, such as the user input system 150. When the control module does receive another motion command from the input device, the method 400 repeats.

[0112] Although illustrative embodiments have been shown and described, a wide range of modification, change and substitution is contemplated in the foregoing disclosure and in some instances, some features of the embodiments may be employed without a corresponding use of other features. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. Thus, the scope of the invention should be limited only by the following claims, and it is appropriate that the claims be construed broadly and in a manner consistent with the scope of the embodiments disclosed herein.

Claims

WHAT IS CLAIMED IS:

1. A computer-assisted system comprising: a repositionable assembly comprising: a proximal repositionable structure comprising a distal portion and a plurality of joints coupling the distal portion to a base, wherein the plurality of joints provides sufficient degrees of freedom to allow a range of joint states of the plurality of joints for a same state of the distal portion, and a distal repositionable structure attached to the distal portion, the distal repositionable structure configured to support and move a working portion of an instrument within a reachable space; a sensor system configured to provide sensor signals indicative of physical configurations of the repositionable assembly; and a control system comprising one or more processors, the control system configured to: command, in response to receiving a motion command from an input device, motion of the plurality of joints that pivots the distal portion about a remote center of motion located at a first location relative to a workspace, determine, based on at least the sensor signals, whether to command a reconfiguration of the proximal repositionable structure to move the distal portion relative to the workspace, such that the reachable space is moved relative to the workspace, and command, in response to a determination to command the reconfiguration, the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, such that the reachable space is moved relative to the workspace and the remote center of motion is maintained at the first location.

2. The computer-assisted system of claim 1, wherein the reachable space is defined by a range of motion limit of the distal repositionable structure, and wherein the range of motion limit comprises a translation limit along an insertion axis of the distal repositionable structure.

3. The computer-assisted system of claim 1, wherein relocating the remote center of motion relative to the distal portion comprises: setting a software remote center of motion; or updating a location of the software remote center of motion such that the software remote center of motion has moved relative to the distal portion.

4. The computer-assisted system of claim 1, wherein to determine to command the reconfiguration, the control system is configured to: determine whether to move the reachable space; and determine whether one or more movement conditions are satisfied.

5. The computer-assisted system of claim 4, wherein a movement condition of the one or more movement conditions is selected from the group consisting of: a receipt of a user command for motion of the repositionable assembly or of the instrument; a performance by the repositionable assembly of a user commanded motion; a receipt of a user command to enter a mode for adjusting a pose of the repositionable assembly; the computer-assisted system entering or being in a mode for adjusting a pose of the repositionable assembly; a receipt of a user command to enter a mode for teleoperation of the repositionable assembly; the computer-assisted system entering or being in a mode for teleoperation of the repositionable assembly; and a detection of movement of at least one joint of the plurality of joints of the repositionable assembly.

6. The computer-assisted system of claim 4, wherein a movement condition of the one or more movement conditions is selected from the group consisting of: a receipt of a user command for motion of the proximal repositionable structure; a performance by the proximal repositionable structure of a user commanded motion; and a detection of non-zero velocity of at least one degree of freedom of the proximal repositionable structure.

7. The computer-assisted system of claim 4, wherein a movement condition of the one or more movement conditions is selected from the group consisting of: a receipt of a user command for an insertion of the instrument; and a performance of the user command for the insertion of the instrument.

8. The computer-assisted system of claim 1, wherein to command the proximal repositionable structure to move the distal portion relative to the workspace, the control system is configured to: command the proximal repositionable structure to move the distal portion relative to the workspace contemporaneously with: commanding an insertion of one or more instruments supported by the distal repositionable structure or a retraction of the one or more instruments.

9. The computer-assisted system of claim 1, wherein to command the proximal repositionable structure to move the distal portion relative to the workspace, the control system is configured to: command the proximal repositionable structure to move the distal portion relative to the workspace contemporaneously with: actuation of one or more joints of the proximal repositionable structure for an objective other than moving the distal portion.

10. The computer-assisted system of claim 1, wherein the control system is further configured to: define a location of a software remote center of motion of the proximal repositionable structure at the first location prior to movement of the distal portion.

11. The computer-assisted system of claim 1, wherein the control system is further configured to: command motion of at least one of the distal repositionable structure or the instrument, such that a position of the working portion of the instrument is maintained relative to the workspace when the distal portion moves during the reconfiguration.

12. The computer-assisted system of claim 1, wherein the control system is further configured to: command an insertion or a retraction of the instrument relative to the workspace contemporaneously with commanding the proximal repositionable structure to move the distal portion during the reconfiguration.

13. The computer-assisted system of claim 1, wherein to determine whether to command the reconfiguration, the control system is configured to: determine to command the reconfiguration of the proximal repositionable structure in response to an indication that an operator is attempting to reach a target in the workspace that is: located outside of the reachable space, or located deeper in the workspace than the reachable space, or located shallower in the workspace than the reachable space.

14. The computer-assisted system of claim 1, wherein to determine whether to command the reconfiguration, the control system is further configured to: determine to command the reconfiguration of the proximal repositionable structure in response to an indication that the working portion is: at a boundary of the reachable space; within a threshold of the reachable space; within a predefined portion of the reachable space; shallower than a minimum depth threshold; or deeper than a maximum depth threshold.

15. The computer-assisted system of claim 14, wherein: a value of the minimum depth threshold is based on at least one of a type of the instrument, a kinematic configuration of the instrument, or a type of procedure performed by the computer-assisted system; or a value of the maximum depth threshold is based on at least one of a type of the instrument, a kinematic configuration of the instrument, or a type of procedure performed by the computer-assisted system.

16. The computer-assisted system of claim 1, wherein: the instrument is included in a plurality of instruments that are supported by the distal repositionable structure; and the control system is further configured to determine to command the reconfiguration of the proximal repositionable structure in response to the sensor signals indicating that a respective working portion of each non-imaging instrument included in the plurality of instruments is deeper than a minimum insertion depth or shallower than a maximum insertion depth.

17. The computer-assisted system of claim 1, wherein to command the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, the control system is configured to: determine to move the distal portion in an insertion direction relative to the workspace in response to an indication an operator is commanding the working portion deeper in the workspace than the reachable space or that the working portion is deeper than a maximum depth threshold; or determine to move the distal portion in a retraction direction relative to the workspace in response to an indication that the operator is commanding the working portion shallower in the workspace than the reachable space or indicating that the working portion is shallower than a minimum depth threshold.

18. The computer-assisted system of claim 1, wherein to command the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, the control system is configured to: determine that a joint of the distal repositionable structure is within a threshold of a range of motion limit of the joint; or determine that a motion commanded by an operator exceeds the range of motion limit of the joint.

19. The computer-assisted system of any of claims 1 to 18, wherein to command the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, the control system is configured to: command the proximal repositionable structure to move the distal portion by a predefined distance along an insertion axis relative to the workspace.

20. The computer-assisted system of any of claims 1 to 18, wherein to command the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, the control system is configured to: determine at least one of an amount or a direction by which to move the distal portion relative to the workspace during the reconfiguration; and command the proximal repositionable structure to move the distal portion by the determined amount or direction.

21. The computer-assisted system of any of claims 1 to 18, wherein to command the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, the control system is configured to: command the proximal repositionable structure to move the distal portion in only an insertion direction relative to the workspace during the reconfiguration.

22. The computer-assisted system of any of claims 1 to 18, wherein to command the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, the control system is configured to: in response to receiving a command to insert the instrument by a total amount from an input device: command the proximal repositionable structure to move the distal portion such that the instrument is inserted by a first portion of the total amount; and command motion of at least one degree of freedom of the distal repositionable structure or the instrument such that the instrument is inserted by a second portion of the total amount.

23. The computer-assisted system of any of claims 1 to 18, wherein to command the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, the control system is configured to: determine a velocity to command a movement of the distal portion during the reconfiguration based on at least one velocity selected from the group consisting of: a linear velocity of the distal repositionable structure, a linear velocity of the proximal repositionable structure, and a linear velocity of the instrument.

24. The computer-assisted system of any of claims 1 to 18, wherein to command the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, the control system is configured to: determine a velocity to command a movement of the distal portion during the reconfiguration based on at least one commanded velocity selected from the group consisting of: a commanded velocity of the distal repositionable structure, a commanded velocity of the proximal repositionable structure, and a commanded velocity of the instrument.

25. The computer-assisted system of any of claims 1 to 18, wherein to command the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, the control system is configured to: determine a velocity to command a movement of the distal portion during the reconfiguration based on a velocity of the motion of the plurality of joints that pivots the distal portion about the remote center of motion.

26. The computer-assisted system of any of claims 1 to 18, wherein to command the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, the control system is configured to: determine a velocity of a movement of the distal portion during the reconfiguration based on a position of the working portion of the instrument relative to the reachable space.

27. The computer-assisted system of claim 26, wherein to determine the velocity of the movement of the distal portion during the reconfiguration, the control system configured to: determine a higher speed in response to the sensor signals indicating that the position of the working portion is within a first threshold of a boundary of the reachable space; and. determine a lower speed in response to the sensor signals indicating that the position of the working portion is not within the first threshold of the boundary.

28. The computer-assisted system of any of claims 1 to 18, wherein to command the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, the control system is configured to: determine a commanded velocity of a movement of the working portion during the reconfiguration; and determine, based on the commanded velocity, a velocity for moving the proximal repositionable structure to move the distal portion during the reconfiguration.

29. The computer-assisted system of any of claims 1 to 18, wherein the control system is further configured to: limit a range of motion of the distal portion during the reconfiguration based on a model of the workspace or on a user defined depth limit.

30. The computer-assisted system of any of claims 1 to 18, wherein the control system is further configured to: determine, based at least on the sensor signals, whether a range of motion limit of one or more joints of the proximal repositionable structure has been reached, whether a collision has occurred between the instrument and material in the workspace, or whether the instrument and the material in the workspace will collide; and disable, in response to a determination that the range of motion limit has been reached or that the collision has occurred or that the instrument and the material will collide, movement of the distal portion during the reconfiguration.

31. A method of operating a repositionable assembly, the method comprising: commanding, by a control system in response to receiving a motion command from an input device, motion of a plurality of joints of a proximal repositionable structure of the repositionable assembly that pivots a distal portion of the proximal repositionable structure about a remote center of motion located at a first location relative to a workspace; determining, by the control system based on at least sensor signals indicative of physical configurations of the repositionable assembly, whether to command a reconfiguration of the proximal repositionable structure to move the distal portion relative to the workspace, such that a reachable space of a working portion of an instrument supported by a distal repositionable structure attached to the distal portion is moved relative to the workspace; and commanding, by the control system in response to a determination to command the reconfiguration, the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion, such that the reachable space is moved relative to the workspace and the remote center of motion is maintained at the first location.

32. The method of claim 31, wherein the reachable space is defined by a range of motion limit of the distal repositionable structure, and wherein the range of motion limit comprises a translation limit along an insertion axis of the distal repositionable structure.

33. The method of claim 31, wherein relocating the remote center of motion relative to the distal portion comprises: setting a software remote center of motion; or updating a location of the software remote center of motion such that the software remote center of motion has moved relative to the distal portion.

34. The method of claim 31, determining to command the reconfiguration comprises: determining whether to move the reachable space; and determining whether one or more movement conditions are satisfied.

35. The method of claim 34, wherein a movement condition of the one or more movement conditions is selected from the group consisting of: a receipt of a user command for motion of the repositionable assembly or of the instrument; a performance by the repositionable assembly of a user commanded motion; a receipt of a user command to enter a mode for adjusting a pose of the repositionable assembly; the repositionable assembly entering or being in a mode for adjusting a pose of the repositionable assembly; a receipt of a user command to enter a mode for teleoperation of the repositionable assembly; the repositionable assembly entering or being in a mode for teleoperation of the repositionable assembly; and a detection of movement of at least one joint of the plurality of joints of the repositionable assembly.

36. The method of claim 34, wherein a movement condition of the one or more movement conditions is selected from the group consisting of: a receipt of a user command for motion of the proximal repositionable structure; a performance by the proximal repositionable structure of a user commanded motion; and a detection of non-zero velocity of at least one degree of freedom of the proximal repositionable structure.

37. The method of claim 34, wherein a movement condition of the one or more movement conditions is selected from the group consisting of: a receipt of a user command for an insertion of the instrument; and a performance of the user command for the insertion of the instrument.

38. The method of claim 31, wherein commanding the proximal repositionable structure to move the distal portion relative to the workspace comprises: commanding the proximal repositionable structure to move the distal portion relative to the workspace contemporaneously with: commanding an insertion of one or more instruments supported by the distal repositionable structure or a retraction of the one or more instruments.

39. The method of claim 31, wherein commanding the proximal repositionable structure to move the distal portion relative to the workspace comprises: commanding the proximal repositionable structure to move the distal portion relative to the workspace contemporaneously with: actuation of one or more joints of the proximal repositionable structure for an objective other than moving the distal portion.

40. The method of claim 31, further comprising: defining, by the control system, a location of a software remote center of motion of the proximal repositionable structure at the first location prior to movement of the distal portion.

41. The method of claim 31, further comprising: commanding motion of at least one of the distal repositionable structure or the instrument, such that a position of the working portion of the instrument is maintained relative to the workspace when the distal portion moves during the reconfiguration.

42. The method of claim 31, further comprising: commanding an insertion or a retraction of the instrument relative to the workspace contemporaneously with commanding the proximal repositionable structure to move the distal portion during the reconfiguration.

43. The method of claim 31, wherein determining whether to command the reconfiguration, comprises: determining to command the reconfiguration of the proximal repositionable structure in response to an indication that an operator is attempting to reach a target in the workspace that is: located outside of the reachable space, or located deeper in the workspace than the reachable space, or located shallower in the workspace than the reachable space.

44. The method of claim 31, wherein determining whether to command the reconfiguration comprises: determining to command the reconfiguration of the proximal repositionable structure in response to an indication that the working portion is: at a boundary of the reachable space; within a threshold of the reachable space; within a predefined portion of the reachable space; shallower than a minimum depth threshold; or deeper than a maximum depth threshold.

45. The method of claim 44, wherein: a value of the minimum depth threshold is based on at least one of a type of the instrument, a kinematic configuration of the instrument, or a type of procedure performed by the method; or a value of the maximum depth threshold is based on at least one of a type of the instrument, a kinematic configuration of the instrument, or a type of procedure performed by the method.

46. The method of claim 31, wherein: the instrument is included in a plurality of instruments that are supported by the distal repositionable structure; and the method further comprises: determining to command the reconfiguration of the proximal repositionable structure in response to the sensor signals indicating that a respective working portion of each non-imaging instrument included in the plurality of instruments is deeper than a minimum insertion depth or shallower than a maximum insertion depth.

47. The method of claim 31, wherein commanding the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion comprises: determining to move the distal portion in an insertion direction relative to the workspace in response to an indication an operator is commanding the working portion deeper in the workspace than the reachable space or that the working portion is deeper than a maximum depth threshold; or determining to move the distal portion in a retraction direction relative to the workspace in response to an indication that the operator is commanding the working portion shallower in the workspace than the reachable space or indicating that the working portion is shallower than a minimum depth threshold.

48. The method of claim 31, wherein commanding the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion comprises: determining that a joint of the distal repositionable structure is within a threshold of a range of motion limit of the joint; or determining that a motion commanded by an operator exceeds the range of motion limit of the joint.

49. The method of any of claims 31 to 48, wherein commanding the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion comprises: commanding the proximal repositionable structure to move the distal portion by a predefined distance along an insertion axis relative to the workspace.

50. The method of any of claims 31 to 48, wherein commanding the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion comprises: determining at least one of an amount or a direction by which to move the distal portion relative to the workspace during the reconfiguration; and commanding the proximal repositionable structure to move the distal portion by the determined amount or direction.

51. The method of any of claims 31 to 48, wherein commanding the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion comprises: commanding the proximal repositionable structure to move the distal portion in only an insertion direction relative to the workspace during the reconfiguration.

52. The method of any of claims 31 to 48, wherein commanding the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion comprises in response to receiving a command to insert the instrument by a total amount from an input device: commanding the proximal repositionable structure to move the distal portion such that the instrument is inserted by a first portion of the total amount; and commanding motion of at least one degree of freedom of the distal repositionable structure or the instrument such that the instrument is inserted by a second portion of the total amount.

53. The method of any of claims 31 to 48, wherein commanding the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion comprises: determining a velocity to command a movement of the distal portion during the reconfiguration based on at least one velocity selected from the group consisting of: a linear velocity of the distal repositionable structure, a linear velocity of the proximal repositionable structure, and a linear velocity of the instrument.

54. The method of any of claims 31 to 48, wherein commanding the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion comprises: determining a velocity to command a movement of the distal portion during the reconfiguration based on at least one commanded velocity selected from the group consisting of: a commanded velocity of the distal repositionable structure, a commanded velocity of the proximal repositionable structure, and a commanded velocity of the instrument.

55. The method of any of claims 31 to 48, wherein commanding the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion comprises: determining a velocity to command a movement of the distal portion during the reconfiguration based on a velocity of the motion of the plurality of joints that pivots the distal portion about the remote center of motion.

56. The method of any of claims 31 to 48, wherein commanding the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion comprises: determining a velocity of a movement of the distal portion during the reconfiguration based on a position of the working portion of the instrument relative to the reachable space.

57. The method of claim 56, wherein determining the velocity of the movement of the distal portion during the reconfiguration comprises: determining a higher speed in response to the sensor signals indicating that the position of the working portion is within a first threshold of a boundary of the reachable space; and. determining a lower speed in response to the sensor signals indicating that the position of the working portion is not within the first threshold of the boundary.

58. The method of any of claims 31 to 48, wherein commanding the proximal repositionable structure to move the distal portion relative to the workspace while relocating the remote center of motion relative to the distal portion comprises: determining a commanded velocity of a movement of the working portion during the reconfiguration; and determining, based on the commanded velocity, a velocity for moving the proximal repositionable structure to move the distal portion during the reconfiguration.

59. The method of any of claims 31 to 48, further comprising: limiting, by the control system, a range of motion of the distal portion during the reconfiguration based on a model of the workspace or on a user defined depth limit.

60. The method of any of claims 31 to 48, further comprising: determining, by the control system based at least on the sensor signals, whether a range of motion limit of one or more joints of the proximal repositionable structure has been reached, whether a collision has occurred between the instrument and material in the workspace, or whether the instrument and the material in the workspace will collide; and disabling, by the control system in response to a determination that the range of motion limit has been reached or that the collision has occurred or that the instrument and the material will collide, movement of the distal portion during the reconfiguration.

61. One or more non-transitory machine-readable media comprising a plurality of machine-readable instructions which when executed by one or more processors associated with a computer-assisted system are adapted to cause the one or more processors to perform the method of any one of claims 31-60.