CN120713648B

CN120713648B - Surgical robot system and its control method, computer equipment

Info

Publication number: CN120713648B
Application number: CN202510924888.6A
Authority: CN
Inventors: 藏磊; 袁硕; 范宁; 王奥博; 陈睿源
Original assignee: Beijing Chaoyang Hospital
Current assignee: Beijing Chaoyang Hospital
Priority date: 2025-07-04
Filing date: 2025-07-04
Publication date: 2026-01-27
Anticipated expiration: 2045-07-04
Also published as: CN120713648A

Abstract

This application relates to a surgical robot system and its control method, as well as a computer device. The method includes: acquiring bone mechanics information of the bone to be removed in the bone-grinding region; determining the coefficient of friction between the bone to be removed and the end effector of the surgical robot system based on the bone mechanics information; determining the desired contact force between the end effector and the bone to be removed during the bone-grinding process based on the coefficient of friction information; the desired contact force is used to ensure that the end effector meets a desired torque during the bone-grinding process. This method ensures that the contact force during the bone-grinding process is within a controllable range, thus improving grinding efficiency and ensuring safety during the surgery.

Description

Surgical robot system, control method thereof and computer equipment

Technical Field

The present application relates to the field of medical devices, and in particular, to a surgical robot system, a control method thereof, and a computer device.

Background

In orthopedics, neurosurgery, and other procedures, bone removal is a critical step in the treatment of skull base lesions, tumor resection, or laminectomy. Traditional bone grinding operation relies on hand-held grinding operation of operators, however, due to complex operation environment, such as complex intracranial anatomy structure, dense distribution of nerve and functional areas, surrounding soft tissue interference and the like, and pathological changes often cause abnormal bone morphology or position variation, the free-hand grinding operation has extremely high requirements on space perception capability and operation precision of the operators, error accumulation is easily caused by fatigue or limited visual field in long-time operation, and the efficiency and safety of bone grinding are greatly reduced.

Disclosure of Invention

In view of the above, it is necessary to provide a surgical robot system, a control method thereof, and a computer device, which can improve the grinding efficiency and the surgical safety.

In a first aspect, the present application provides a control method of a surgical robot system, including:

acquiring bone mechanical information of bone to be ground in a bone region to be ground;

determining friction coefficient information between the bone to be ground and an end effector of the surgical robotic system based on the bone mechanics information;

And determining the expected contact force of the end effector and the bone to be ground during bone grinding based on the friction coefficient information, wherein the expected contact force is used for enabling the end effector to meet expected torque during bone grinding.

In one embodiment, the determining friction coefficient information between the bone to be ground and an end effector of the surgical robotic system based on the bone mechanics information includes:

acquiring a preset first mapping relation, and acquiring bone mechanics information of the bone to be ground according to the first mapping relation and the image gray information of the bone medical image of the bone to be ground, wherein the first mapping relation is used for representing the corresponding relation between the image gray and the bone mechanics information;

Acquiring a preset second mapping relation, and determining friction coefficient information between the bone to be ground and the end effector according to the second mapping relation and the bone mechanics information of the bone to be ground, wherein the second mapping relation is used for representing the corresponding relation between the friction coefficient of the end effector and the bone mechanics information.

In one embodiment, the determining the desired contact force of the end effector with the bone to be ground during bone grinding based on the coefficient of friction information comprises:

obtaining a desired friction force of the end effector under the condition of meeting the desired torque according to the desired torque corresponding to the end effector and the structural parameters of the end effector;

And combining the expected friction force and the friction coefficient information to obtain the expected contact force of the end effector and the bone to be ground in the bone grinding process.

In one embodiment, the method further comprises:

Determining a first interface and a second interface in the to-be-ground bone region, wherein the first interface is the upper surface of the to-be-ground bone region, and the second interface is positioned above the boundary of the bone layer corresponding to the to-be-ground bone region;

The first interface is used as a grinding starting surface, the second interface is used as a grinding ending surface, and a planned grinding path corresponding to the to-be-ground bone region is obtained;

The planned grinding path comprises at least one two-dimensional curve in a two-dimensional space where each grinding layer is located, and a plurality of grinding layers are distributed layer by layer along the direction from the first interface to the second interface.

In one embodiment, the obtaining the planned grinding path corresponding to the to-be-ground bone region includes:

determining a percutaneous immobility point corresponding to the end effector, wherein the percutaneous immobility point is positioned on the surface of the skin and is associated with the spatial position of the to-be-ground bone region;

Taking the percutaneous stationary point as a rotation reference point of the end effector to obtain a plurality of concentric circle paths;

the two-dimensional curve in the planned grinding path comprises a plurality of sections of sub-curves, and the plurality of sections of sub-curves comprise circumferential sections of the plurality of concentric circle paths in the to-be-ground bone region.

In one embodiment, the radial distance between the concentric circle paths is determined according to the image gray level information of the bone medical image from which bone is to be ground, wherein the radial distance between the concentric circle paths in a high gray level region is smaller than the radial distance between the concentric circle paths in a low gray level region, and the image gray level value of the high gray level region is larger than the image gray level value of the low gray level region.

In one embodiment, the method further comprises:

acquiring current grinding information of the end effector in the bone grinding process of removing bone to be ground, wherein the current grinding information comprises the current position, the current feedback force and the current speed of the end effector;

determining target position information of the end effector through expected grinding information of the end effector and the current grinding information, wherein the expected grinding information comprises an expected position of the end effector, an expected contact force corresponding to the expected position and a preset expected speed;

And outputting a movement instruction for controlling the mechanical arm according to the target position information of the end effector, wherein the mechanical arm is used for driving the end effector to perform bone grinding operation, and the movement instruction is used for indicating a plurality of groups of joint point information which need to be moved by the mechanical arm.

In one embodiment, the method further comprises:

Acquiring a three-dimensional image of a target object and target pose information of an optical mark of the target object in the three-dimensional image;

acquiring the pose relationship between the optical mark of the end effector and the optical mark of the target object in real time through a visual camera;

Determining the terminal pose information of the optical mark of the end effector in the three-dimensional image according to the target pose information and the pose relation of the target object;

and loading the three-dimensional model of the end effector into the three-dimensional image of the target object through the end pose information so as to determine the relative position of the end effector and the target object.

In a second aspect, the present application also provides a surgical robotic system comprising:

A mechanical arm;

The end effector is connected with the tail end of the mechanical arm and is used for performing bone grinding operation under the drive of the mechanical arm;

The controller is connected with the mechanical arm, and comprises a memory and a processor, wherein the memory stores a computer program, and the processor realizes the steps of the control method of the surgical robot system provided by the first aspect of the application when executing the computer program.

In a third aspect, the present application also provides a computer device, including a memory and a processor, where the memory stores a computer program, and the processor implements the steps of the control method of the surgical robot system provided in the first aspect of the present application when the computer program is executed.

The surgical robot system, the control method thereof and the computer equipment are characterized by acquiring bone mechanics information of bone to be ground in a bone to be ground area, determining friction coefficient information between the bone to be ground and an end effector of the surgical robot system based on the bone mechanics information, determining expected contact force between the end effector and the bone to be ground in a bone grinding process based on the friction coefficient information, wherein the expected contact force is used for enabling the end effector to meet expected torque in the bone grinding process. The controller of the application determines the friction coefficient information of the end tool and the bone surface through the bone mechanical information of bone to be ground before operation, calculates the expected contact force of the end effector and the bone surface by combining the friction coefficient and the torque limit of the end effector, and converts the torque control into the contact force control through the friction constraint, so that the mechanical arm can be controlled to adjust the contact force of the end effector and the bone surface according to the expected contact force in the bone grinding process, thereby the end effector can achieve higher grinding efficiency through adjusting the contact force, the contact force in the bone grinding process can be ensured to be in a control range, the grinding efficiency is improved, and the safety in the operation process is ensured.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the related art, the drawings that are required to be used in the embodiments or the related technical descriptions will be briefly described, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

FIG. 1 is a schematic diagram of a surgical robotic system in one embodiment;

FIG. 2 is a flow chart of a method of controlling a surgical robotic system in one embodiment;

FIG. 3 is a flow chart of a method of controlling a surgical robotic system in another embodiment;

FIG. 4 is a flow chart of another embodiment for determining a desired contact force;

FIG. 5 is a schematic illustration of an initial region of bone to be ground in one embodiment;

FIG. 6 is a schematic view of an initial region of bone to be ground in another embodiment;

FIG. 7 is a schematic illustration of a 3D contour model of an initial region of bone to be ground in one embodiment;

FIG. 8 is a schematic illustration of the final determination of a region of bone to be ground in one embodiment;

FIG. 9 is a schematic illustration of the final determination of the region of bone to be ground in another embodiment;

FIG. 10 is a schematic diagram of a first interface and a second interface in one embodiment;

FIG. 11 is a schematic view of a first interface and a second interface in another embodiment;

FIG. 12 is a flow diagram of one embodiment for obtaining a planned grinding path;

FIG. 13 is a schematic illustration of a planned grinding path in one embodiment;

FIG. 14 is a schematic diagram of a planned grinding path in one embodiment;

FIG. 15 is a flow chart of another embodiment for obtaining a planned grinding path;

FIG. 16 is a flow chart illustrating the determination of the relative positions of an end effector and an area to be ground in one embodiment;

FIG. 17 is a flow chart of outputting motion commands to a robotic arm in one embodiment;

Fig. 18 is an internal structural view of a computer device in one embodiment.

Detailed Description

The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

In orthopedics, neurosurgery, and other procedures, bone removal is a critical step in the treatment of skull base lesions, tumor resection, or laminectomy. For example, single-sided, dual-channel spinal endoscopy (UBE) surgery has become an important method for treating degenerative spinal disorders, the key operation of which is the bone grinding of the posterior vertebral segment lamina of the spine by the operator's hand-held high-speed abrasive drill. The bone grinding range and precision in the operation are highly dependent on the experience of the operator, the whole bone grinding duration is long, the operator needs to concentrate attention and hold a grinding drill for a long time, so that the whole bone grinding operation is extremely easy to cause the hand brain fatigue of the operator, in addition, the operation space of an operation area is limited, and the precision, efficiency and safety of the bone grinding can be reduced due to the interference of soft tissues such as surrounding muscles and the like, and the risk of injuries of spinal cord and nerve roots is increased.

In order to improve the grinding efficiency and the surgical safety, an embodiment of the present application provides a control method of a surgical robot system, referring to fig. 1, the surgical robot system may include a robot arm 200, an end effector 400 for connecting with the end of the robot arm 200, and a controller 100 signal-connected with the robot arm 200. The surgical robotic system may also include a sensing device 300, the sensing device 300 being secured to the end of the robotic arm 200 and the end effector 400 being fixedly mounted to the sensing device 300.

In an exemplary embodiment, as shown in fig. 2, a control method of a surgical robot system is provided, and an example of application of the method to the controller 100 in fig. 1 is described, including the following steps 202 to 206. Wherein:

step 202, obtaining bone mechanical information of bone to be ground in a bone region to be ground.

The bone region to be ground refers to a bone region to be ground in bones of a target object. The bone mechanical information is used to characterize the anti-grinding ability of the bone to be ground, and may include bone density information or bone hardness information of the bone to be ground, etc.

For example, before an operation, a target object, that is, a target area of a patient is scanned by a medical imaging technology such as CT or MRI to obtain three-dimensional image data of the target area, a controller selects an area to be ground from the target area according to the three-dimensional image data, and obtains bone density information or bone hardness information of bone to be ground according to the three-dimensional image data.

Step 204, determining friction coefficient information between the bone to be ground and an end effector of the surgical robotic system based on the bone mechanics information.

Wherein the coefficient of friction information is used to reflect the strength of interaction of the end effector with bone to be abraded, which may include the coefficient of friction.

For example, the embodiment of the application can pre-establish the mapping relation between the friction coefficient between the bone and the end effector such as the high-speed grinding drill and the bone with different bone mechanical information, and the controller can match or calculate the friction coefficient between the bone to be ground and the grinding drill before the operation based on the mapping relation and the bone mechanical information of the bone to be ground.

At step 206, a desired contact force of the end effector with bone to be removed during bone milling is determined based on the coefficient of friction information.

Wherein the desired contact force is used to cause the end effector to meet a desired torque during bone milling, which may refer to a rated torque of the end effector, or which may be determined based on a maximum output torque that the end effector can withstand without stalling.

The controller of the embodiment of the application combines the friction coefficient and the torque limit of the end effector before operation, calculates the expected contact force between the end effector and the bone surface, and can control the mechanical arm to adjust the contact force between the end effector and the bone surface according to the expected contact force in the bone grinding process, thereby enabling the end effector to achieve higher grinding efficiency by adjusting the contact force, and ensuring that the actual torque of the end effector is always stable within a safe range in the grinding process.

According to the control method of the surgical robot system, the bone mechanical information of the bone to be ground in the bone to-be-ground area is obtained, the friction coefficient information between the bone to be ground and the end effector of the surgical robot system is determined based on the bone mechanical information, and the expected contact force between the end effector and the bone to be ground in the bone grinding process is determined based on the friction coefficient information and is used for enabling the end effector to meet the expected torque in the bone grinding process. According to the controller provided by the embodiment of the application, before an operation, the friction coefficient information of the end tool and the bone surface is determined through the bone mechanical information of bone to be ground, the friction coefficient and the torque limit of the end effector are combined, the expected contact force of the end effector and the bone surface is calculated, and the torque control is converted into the contact force control through the friction constraint, so that the mechanical arm can be controlled to adjust the contact force of the end effector and the bone surface according to the expected contact force in the bone grinding process, the end effector can achieve higher grinding efficiency through adjusting the contact force, the contact force in the bone grinding process can be ensured to be within a control range, the grinding efficiency is improved, and the safety in the operation process is ensured.

In one exemplary embodiment, as shown in fig. 3, there is provided a control method of a surgical robot system, the method comprising:

step 302, obtaining the image gray information of the region to be ground from the three-dimensional image data of the region to be ground.

Step 304, a first mapping relation between preset image gray information and bone mechanics information is obtained, and bone mechanics information of bone to be ground in the bone region to be ground is obtained according to the first mapping relation and the image gray information.

The first mapping relation is used for representing a corresponding relation between image gray level in the bone three-dimensional image and bone mechanical information of the bone.

Step 306, obtaining a preset second mapping relation, and determining friction coefficient information between the bone to be ground and the end effector according to the second mapping relation and bone mechanics information of the bone to be ground.

The second mapping relation is used for representing the corresponding relation between the friction coefficient of the end effector and the bone mechanical information.

For bones, a higher hardness corresponds to a higher coefficient of friction, while bone hardness is mainly determined by the mineral content, especially the content of hydroxyapatite crystals, and the increase of the mineral content directly improves the bone density. In the medical image scanned by CT or MRI, the gray value and the bone density are directly related, so that the friction coefficient, the hardness, the bone density and the image gray value have a direct or indirect mapping relation. The embodiment of the application can collect different bones through multiple sampling and calculate the first mapping relation between the gray level information of the image and the bone mechanics information and the second mapping relation between the bone mechanics information and the friction coefficient.

For example, please refer to fig. 4, the controller of the embodiment of the present application extracts the gray value G of the region to be ground from the preoperative three-dimensional image, obtains the bone density ρ of the bone to be ground based on a first mapping relationship between the gray level of the image and the bone density, such as ρ=f (G), and determines the friction coefficient μ between the bone to be ground and the end effector based on a second mapping relationship between the bone density and the friction coefficient, such as μ=f (ρ, a).

And 308, obtaining the expected friction force of the end effector under the condition of meeting the expected torque according to the expected torque corresponding to the end effector and the structural parameters of the end effector.

In the bone grinding execution process, the optimal state is that the grinding drill can be executed according to the expected torque, wherein the expected torque is generally the rated torque of the grinding drill, and if the built-in parameter of the grinding drill does not provide the rated torque, the maximum output torque which can be born when the grinding drill is not blocked can be usedAs calculated, with continued reference to fig. 4,The desired torque may be expressed as:

;

Wherein, the As a safety factor, a proper value can be selected according to different environments.

Assuming that the abrasive drill is contacted with the target object, namely the conical plate of the patient from the side edge, the moment from the contact point to the abrasive drill center is the abrasive drill radius r _burr, the moment generated by the friction force is the largest, and the expected friction force f _d is obtained and expressed as f _d =/r_burr。

Step 310, combining the expected friction force and the friction coefficient information, obtaining the expected contact force of the end effector corresponding to a grinding contact point in the process of grinding bones.

Illustratively, F _d=f_d/μ is obtained according to the friction calculation formula, and the final relation is obtained by finishing:

;

Wherein, the Expressed as the desired contact force.

In a preferred embodiment of the present application, different bones may be acquired through multiple sampling, gray values and surface friction coefficients thereof may be measured and calculated, and the obtained data may be integrated and then subjected to linearization processing, so as to directly obtain a corresponding relationship between the friction coefficient of the end effector and the bone and the image gray level of the bone medical image, and the corresponding relationship may be preset as a third mapping relationship, so that after the controller obtains the image gray level information of the bone to be ground, friction coefficient information matched with the image gray level information may be determined directly according to the preset third mapping relationship, for example μ=f (G).

In a preferred embodiment, the controller acquires a planned grinding path corresponding to the region to be ground in advance, and determines the gray value of each path point on the planned grinding path through the medical image information to obtain the image gray information. The controller can obtain the bone density of each path point through the preset first mapping relation and the gray value of each path point, and then determine the friction coefficient corresponding to each path point through the preset second mapping relation and the bone density of each path point, or the controller can directly determine the friction coefficient corresponding to each path point through the preset third mapping relation and the gray value of each path point, and then calculate the expected contact force required by each path point.

In this embodiment, through the mapping relationship between the friction coefficient and the image gray level of the bone medical image, the friction coefficient information of the bone surface is determined according to the image gray level information of the bone to be ground, and then the desired contact force is calculated through the friction coefficient information and the desired friction force of the end effector under the desired torque, the mechanical arm can control the contact force between the grinding bit and the bone surface, and after the relationship between the desired contact force and the maximum output torque is determined, the grinding bit can achieve higher grinding efficiency by adjusting the contact force. Meanwhile, by directly establishing a mapping relation between the friction coefficient and the image gray scale, the friction coefficient corresponding to the bone to be ground can be quickly obtained after the image gray scale value corresponding to the bone to be ground is determined.

In an exemplary embodiment, before step 202, the control method of the surgical robot system may further include a step of determining a region to be ground, and the step of determining the region to be ground may include the controller acquiring a three-dimensional image of a target region of the target object, in response to a selection operation of an initial region of interest in the three-dimensional image, the controller may segment different tissue materials of the initial region of interest, and generate a three-dimensional model corresponding to the initial region of interest in combination with bone surface information, so that an operator determines the target region of interest according to the three-dimensional model, in response to a selection operation of the target region of interest in the three-dimensional model corresponding to the initial region of interest, the controller extracts a first interface and a second interface from the target region of interest, and determines the region to be ground using the first interface and the second interface.

The first interface is the upper surface of bone in the target region of interest, the second interface is the safety interface above the boundary of the bone layer in the target region of interest, and after the first interface and the second interface are extracted from the target region of interest, the controller finally determines the region to be ground by taking the first interface as the initial plane of projection of the region to be ground along the sagittal axis direction and the second interface as the termination plane of projection of the region to be ground along the sagittal axis direction. For example, referring to fig. 5, 6 and 7 in combination, the operator may frame the rough surgical region, i.e., the initial region of interest 1 (fig. 5 and 6), in the image view, the controller may segment the skin, soft tissue and bone surface of the patient according to the image segmentation algorithm after the initial region of interest 1 is confirmed, extract the vertebral surface information, and automatically generate the 3D contour model of the initial region of interest 1 (fig. 7), so that the operator may more intuitively observe the condition of the surgical region to determine the bone grinding region.

Referring to fig. 8 and 9 in combination, the operator frames the portion to be polished in the 3D contour model and/or other views corresponding to the segmented initial region of interest 1 to determine the target region of interest 10.

Referring to fig. 10 and 11 in combination, after determining the target region of interest 10, the controller may segment the upper surface of the bone in the target region of interest 10, i.e. the first interface 11, and the controller may segment the safety interface above the boundary 13 of the bone layer in the target region of interest 10, i.e. the second interface 12. For safety reasons, to avoid damage to nerves or tissues under the bone caused by chipping generated during grinding of the lower surface 14 by the abrasive drill and vibration of the abrasive drill, the controller will extract the complete bone layer boundary 13 from the target region of interest 10, and leave the preset thickness t as a safety boundary based on the position of the bone layer boundary 13, where t may be 1-2 mm, resulting in the second interface 12. The first interface 11 is taken as an initial plane of projection of the region to be ground along the sagittal axis, and the second interface 12 is taken as a final plane of projection of the region to be ground along the sagittal axis, so that the region to be ground is finally determined.

In this embodiment, the target region of interest to be polished can be accurately planned by combining the image technology and the segmentation algorithm, and from the safety point of view, the first interface is selected as the initial plane of projection of the region of interest to be polished along the sagittal axis, and the second interface is selected as the termination plane of projection of the region of interest to be polished along the sagittal axis, so as to determine the region of interest to be polished, thereby avoiding damage to nerves or tissues to the greatest extent and improving safety.

In one exemplary embodiment, as shown in fig. 12, the control method of the surgical robot system further includes:

step 1202, determining a first interface and a second interface in the region to be ground.

The first interface 11 and the second interface 12 are an initial plane and a final plane of projection of the region to be ground along the sagittal axis, respectively. The first interface 11 may be an upper surface of the to-be-ground bone region, the second interface 12 may be a lower surface of the to-be-ground bone region, and the second interface 12 is located above a boundary of a bone layer corresponding to the to-be-ground bone region.

And 1204, obtaining a planned grinding path corresponding to the to-be-ground bone region by taking the first interface as a grinding starting surface and the second interface as a grinding ending surface, wherein the planned grinding path is used for indicating and controlling a moving track of the end effector in the bone grinding process of the to-be-ground bone region.

For example, the controller may take the upper surface of the to-be-ground bone region, i.e. the first interface 11, as a starting surface for performing bone grinding, take the lower surface of the to-be-ground bone region, i.e. the second interface 12, as a terminating surface for performing bone grinding, distribute a plurality of grinding layers layer by layer along the direction from the first interface to the second interface, and plan the grinding path to include at least one two-dimensional curve in a two-dimensional space where each grinding layer is located. For example, the two-dimensional curve may be a continuous curve with each grinding layer having a first boundary and a second boundary, the two-dimensional curve detouring between the first boundary and the second boundary, and the two-dimensional curve not intersecting itself.

For example, please refer to fig. 13 and 14, a layer-by-layer polishing path is planned from the first interface 11 to the second interface 12, the abrasive drill starts from the upper surface, i.e. the first interface 11, and uses the midpoint S (fig. 11 and 13) of the frame line at the edge of the cone section, which is close to the upper surface, as a polishing starting point, to make an S-shaped round reciprocating motion, after the path traverses a layer to reach the layer end point E, the abrasive drill is fed downward by a fixed depth, and then the above steps are repeated until reaching the second interface 12.

It will be appreciated that although the grinding layer path is described in this embodiment as a two-dimensional curve in a two-dimensional plane, in practice there may be three-dimensional undulations in each grinding layer due to irregularities in the bone surface topography. The two-dimensional curve is a simplified representation after the actual three-dimensional path is orthogonally projected to an ideal reference plane, and the height deviation of the two-dimensional curve and the real bone surface can be accurately tracked through the real-time force position compensation control of the surgical robot.

In an exemplary embodiment, as shown in fig. 15, the step 1204 may include:

step 1502, a percutaneous immobilization point corresponding to the end effector is determined, wherein the percutaneous immobilization point is located on the skin surface and is associated with the spatial position of the bone region to be ground.

Illustratively, to meet the needs of minimally invasive surgery, a small incision is typically made in the skin surface as a percutaneous immobile point q of the burr, which is rotated about the q point during the bone milling process, the q point being determined by the operator based on the location of the lesion. The embodiment of the application applies an optical probe to calibrate the position of the percutaneous immobilization point. Firstly, synchronously displaying the position of a probe in an image of an upper computer, placing the probe on the surface of skin, observing the relative positions of the probe and a focus in the image, and finally determining a q point by considering the angle of abrasive drilling insertion and operation.

Step 1504, using the percutaneous immobilization point as a rotational reference point of the end effector, obtaining a plurality of concentric circular paths.

Step 1506, obtaining the planned grinding path according to the plurality of concentric circle paths.

Wherein the two-dimensional curve in the planned grinding path comprises a plurality of sub-curves, and the plurality of sub-curves comprise a plurality of circumferential sections of the concentric circle path in the region to be ground.

For example, please continue to refer to fig. 13 and 14, with the first interface 11 as an initial surface, the controller automatically calculates and generates a semi-elliptical region in each grinding layer in the region to be ground and a concentric circle grinding track inside the semi-elliptical region in a plane according to the square frame planned in fig. 8. The grinding drill surrounds the percutaneous point, a plurality of concentric circle paths are determined on each grinding layer, the concentric circle paths are intercepted under the boundary constraint of the semi-elliptical area in the to-be-ground bone area, and the circumference sections of the concentric circle paths are obtained, wherein the planned grinding path of each grinding layer comprises the circumference sections. And in the same concentric circle, planning a grinding path layer by layer according to the first interface to the second interface, and performing S-shaped tour reciprocating motion from the upper surface by the grinding drill through the circumferential sections and the connecting curves among the circumferential sections. After traversing a layer, the burr is fed down a fixed depth and then the above steps are repeated until the second interface is reached.

In an alternative embodiment, the radial spacing between the plurality of concentric circle paths is determined according to the image gray level information, wherein the radial spacing between the concentric circle paths in a high gray level region is smaller than the radial spacing between the concentric circle paths in a low gray level region, and the image gray level value of the high gray level region is greater than the image gray level value of the low gray level region.

In the embodiment of the application, the grinding drill surrounds the percutaneous fixed point, the grinding path planning of the concentric circle is performed from the grinding starting point, the density degree of the concentric circle is determined based on the gray value, the density of the concentric circle is positively correlated with the gray value, namely, the larger the gray value is, the larger the bone density is, the finer grinding is needed, and the denser the concentric circle is, so that the cutting is ensured to be complete.

In the embodiment, the planned grinding path of bone grinding is completed before operation, and an operator can intuitively determine the area to be ground and the walking path of the grinding drill, so that the operation process is clearer. Meanwhile, by combining the planned grinding path and the image gray value of each path point, the optimal contact force corresponding to each path point respectively, namely the expected contact force, can be calculated before operation.

In one exemplary embodiment, as shown in fig. 16, the control method of the surgical robot system further includes:

In step 1602, a three-dimensional image of a target object and target pose information of an optical marker of the target object in the three-dimensional image are obtained.

The three-dimensional image of the target object is used for indicating the three-dimensional image of a target area of the target object, and the target area comprises a bone area to be ground. For example, the three-dimensional image of the target object may refer to a three-dimensional image of a spinal column segment of a patient.

Step 1604, obtaining, in real time, a pose relationship between the optical marker of the end effector and the optical marker of the target object by a vision camera.

In step 1606, end pose information of the optical marker of the end effector in the three-dimensional image is determined according to the target pose information and the pose relationship of the target object.

In step 1608, the three-dimensional model of the end effector is loaded into the three-dimensional image of the target object through the end pose information to determine the relative position of the end effector and the target object.

Illustratively, optical markers are added on the abrasive drill and the spine of the patient, the pose relationship of the abrasive drill and the spine of the patient is recorded by using a visual camera, and a matrix is transformed by 4*4The representation (wherein,Indicating the optical marking of the abrasive drill,Representing patient optical markers). CT scanning is carried out on the patient to obtain a three-dimensional image, and a transformation matrix of the optical mark of the patient under the image coordinate system is extracted from the three-dimensional imagePose information of the optical mark of the abrasive drill under the image coordinate system can be calculated, and can be expressed as:。

3D model of abrasive drilling is built through three-dimensional software, and the pose of the optical mark of the abrasive drilling in the image is calculated And the optical mark and the abrasive drill are in rigid connection, the 3D model of the abrasive drill is loaded into the image, and the fused image is displayed in the upper computer, so that an operator can clearly and intuitively observe the execution condition of the abrasive drill under the condition that an operation area is blocked by the abrasive drill or skin tissues.

In the embodiment, the vision and image technology is applied to improve the bone grinding precision, the region to be ground and the grinding position are determined by combining the vision and CT image, and the modeling and real-time display of the grinding position and the grinding posture in the image can be realized through three-dimensional software, so that an operator can accurately perceive the relative position of the grinding drill and the spine in real time.

In one exemplary embodiment, as shown in fig. 17, the control method of the surgical robot system further includes:

Step 1702, obtaining current grinding information of the end effector in the bone grinding process of removing bone, wherein the current grinding information comprises a current position, a current feedback force and a current speed of the end effector.

Wherein the current feedback force of the end effector may refer to a component of a contact force between the end effector and the current ground contact point in a current displacement direction.

Step 1704, determining target position information for the end effector from the desired grinding information for the end effector and the current grinding information.

The expected grinding information comprises an expected position, an expected contact force corresponding to the expected position and a preset expected speed, and the expected position is determined according to the planned grinding path. The target position information refers to the target position of the end effector next step.

Step 1706, outputting a motion instruction of the control mechanical arm according to the target position information of the end effector.

For example, the sensing device 300 of the surgical robot system may be a six-dimensional force sensor, and the mechanical arm admittance control based on the end six-dimensional force sensor is applied in the bone grinding process, which can complete the compliant motion in six degrees of freedom, but if the mechanical arm deviates from the track under the given multi-segment straight line track, it cannot be judged whether the grinding is completed, so the embodiment of the application can only adopt force control in the high-speed grinding displacement direction, and the force control model is designed as follows:

;

Where a is the desired acceleration of the end effector, F, V, X is the component of the current contact force in the current displacement direction, the current speed and the current position of the tool, F _d、V_d、X_d is the desired contact force, the desired speed and the desired position, B is the damping coefficient, K is the stiffness coefficient, and M is the mass coefficient, respectively.

The desired contact force F _d, the desired speed V _d and the desired position X _d may be determined by determining the desired position as the next position of the end effector according to the planned grinding path, determining the desired contact force before the end effector contacts the bone at the desired position based on the friction coefficient information in the step 206, determining the desired speed as the limit speed at which the bone is not locked, testing the limit speed at which the bone is not locked by constant speed grinding, and assigning V _d.

Wherein the current position X, the current feedback force F, and the current velocity V of the end effector may be determined by the sensing device 300 obtaining a force component F _p to the end effector 400. The velocity component V _b and the position component X _b of the base coordinate system (the geodetic coordinate system, i.e. the world coordinate system) can be obtained from the mechanical arm, and the velocity component V _b and the position component X _b need to be integrated from the base coordinate system to the end effector, i.e. the tool end, wherein:

;

Wherein b denotes a base coordinate system and f denotes a flange coordinate system. Then, three components are projected in the displacement direction, and the displacement direction is planned to be expressed as Dir in a tool coordinate system and is a unit vector. There are the following transformations:

;

after the desired acceleration a of the end effector is calculated by the force control model, the desired acceleration a of the end effector needs to be mapped back to the base coordinate system by coordinate transformation:

;

Where a _b is the end effector desired acceleration in the base coordinate system.

And integrating the a _b twice to obtain a position vector x _b of the end effector in the next step, and taking the position vector x _b as target position information of the end effector in a base coordinate system.

In the embodiment of the application, the difference between the current feedback force and the expected contact force is taken as a dominant force control model through the admittance control, the dominant force control model generates the core drive of the acceleration and the next step of position vector, the difference between the current position and the expected position and the difference between the current speed and the expected speed are taken as the dynamic response of the correction force control, so that the difference from the expected contact force is converted into an acceleration instruction, the displacement instruction is generated through integration, and finally the displacement instruction is executed by a position control closed loop of the mechanical arm.

Illustratively, after determining the target position information of the end effector, i.e., the next step position vector x _b, the controller outputs a motion command for controlling the robotic arm according to the target position information. Because the incision is required to be smaller in minimally invasive surgery, a channel is usually established on the surface of the skin at a position 10-15 cm away from the focus, the mechanical arm drives the high-speed grinding drill to grind, so that the grinding drill is difficult to adopt translational movement at a pure position, and the grinding drill needs to rotate around the incision, namely a percutaneous fixed point. After the position of the grinding end, namely target position information x _b, is determined, the three-dimensional vector from x _sur to x _b is taken as the Z direction of the end tool, the other two directions are solved by taking the minimum energy consumption as a standard, finally, each joint angle is solved through inverse kinematics of the mechanical arm, and a plurality of groups of joint point information comprising each joint angle are issued to the mechanical arm system by the controller as a movement instruction.

In this embodiment, the sensing device 300 of the surgical robot system may be a six-dimensional force sensor, the mechanical arm may apply a six-degree-of-freedom mechanical arm admittance control method based on the end six-dimensional force sensor, the mechanical arm based on the end six-dimensional force sensor performs adaptive contact force grinding based on the expected contact force, and the contact force between the high-speed grinding and the bone is controlled in real time, so that the contact force in the bone grinding process is ensured to be within a control range, and the bone grinding is completed at the fastest grinding rate on the optimal path.

It should be understood that, although the steps in the flowcharts related to the embodiments described above are sequentially shown as indicated by arrows, these steps are not necessarily sequentially performed in the order indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in the flowcharts described in the above embodiments may include a plurality of steps or a plurality of stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of the steps or stages is not necessarily performed sequentially, but may be performed alternately or alternately with at least some of the other steps or stages.

It will be appreciated that the term "based on" as used herein to describe one or more factors that influence a determination is not to be taken as excluding other factors that may influence the determination. For example, the phrase "determining a based on B" means that the determination of a may be based, at least in part, on or entirely on factor B, that is, B is one factor affecting the determination of a, but does not exclude that the determination of a is also based on C.

Based on the same inventive concept, the embodiment of the application also provides a surgical robot system. The implementation of the solution provided by the system is similar to the implementation described in the above method, so the specific limitations in one or more embodiments of the surgical robot system provided below may be referred to above as limitations on the control method of the surgical robot system, and will not be repeated here.

In an exemplary embodiment, the surgical robot system includes a robot arm 200, an end effector 400, and a controller 100, the end effector 400 being connected to an end of the robot arm 200, the end effector 400 being for performing a bone grinding operation under the driving of the robot arm 200.

The surgical robotic system may also include a sensing device 300, the sensing device 300 being secured to the end of the robotic arm 200 and the end effector 400 being fixedly mounted to the sensing device 300.

The controller 100 is connected to the mechanical arm 200 and the sensor device 300, respectively, and the controller 100 includes a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the control method of the surgical robot system when executing the computer program.

In an exemplary embodiment, a computer device, which may be a terminal, is provided, and an internal structure thereof may be as shown in fig. 18. The computer device includes a processor, a memory, an input/output interface, a communication interface, a display unit, and an input means. The processor, the memory and the input/output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input/output interface. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The input/output interface of the computer device is used to exchange information between the processor and the external device. The communication interface of the computer device is used for carrying out wired or wireless communication with an external terminal, and the wireless mode can be realized through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. The computer program, when executed by the processor, implements a method of controlling a surgical robotic system. The display unit of the computer device is used for forming a visual picture, and can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer equipment can be a touch layer covered on the display screen, can also be a key, a track ball or a touch pad arranged on the shell of the computer equipment, and can also be an external keyboard, a touch pad or a mouse and the like.

It will be appreciated by those skilled in the art that the structure shown in FIG. 18 is merely a block diagram of some of the structures associated with the present inventive arrangements and is not limiting of the computer device to which the present inventive arrangements may be applied, and that a particular computer device may include more or fewer components than shown, or may combine some of the components, or have a different arrangement of components.

It should be noted that, the user information (including but not limited to user equipment information, user personal information, etc.) and the data (including but not limited to data for analysis, stored data, presented data, etc.) related to the present application are both information and data authorized by the user or sufficiently authorized by each party, and the collection, use and processing of the related data are required to meet the related regulations.

Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, database, or other medium used in embodiments provided herein may include at least one of non-volatile and volatile memory. The nonvolatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical Memory, high density embedded nonvolatile Memory, resistive random access Memory (ReRAM), magneto-resistive random access Memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric Memory (Ferroelectric Random Access Memory, FRAM), phase change Memory (PHASE CHANGE Memory, PCM), graphene Memory, and the like. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, and the like. By way of illustration, and not limitation, RAM can be in various forms such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), etc. The databases referred to in the embodiments provided herein may include at least one of a relational database and a non-relational database. The non-relational database may include, but is not limited to, a blockchain-based distributed database, and the like. The processor referred to in the embodiments provided in the present application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, or the like, but is not limited thereto.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing examples illustrate only a few embodiments of the application and are described in detail herein without thereby limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of the application should be assessed as that of the appended claims.

Claims

1. A control method for a surgical robot system, characterized in that the method comprises:

Obtain bone mechanics information of the bone to be removed in the area to be ground down;

Based on the bone mechanics information, the friction coefficient between the bone to be removed and the end effector of the surgical robot system is determined.

Based on the friction coefficient information, the desired contact force between the end effector and the bone to be removed during the bone grinding process is determined; the desired contact force is used to ensure that the end effector meets the desired torque during the bone grinding process;

The method further includes:

A first interface and a second interface are defined in the bone-grinding region; the first interface is the upper surface of the bone-grinding region, and the second interface is located above the bone layer boundary corresponding to the bone-grinding region.

Using the first interface as the grinding start surface and the second interface as the grinding end surface, a planned grinding path corresponding to the bone area to be ground is obtained; the planned grinding path is used to indicate the movement trajectory of the end effector during the bone grinding process in the bone area to be ground; wherein, the planned grinding path includes at least one two-dimensional curve in the two-dimensional space where each grinding layer is located, and multiple grinding layers are distributed layer by layer along the direction from the first interface to the second interface.

Obtaining the planned grinding path corresponding to the bone region to be ground includes:

Determine the percutaneous fixed point corresponding to the end effector; the percutaneous fixed point is located on the skin surface and is associated with the spatial position of the area to be bone-reduced.

Using the percutaneous fixed point as the rotation reference point of the end effector, multiple concentric circle paths are obtained;

The planned grinding path is obtained based on multiple concentric circle paths; the two-dimensional curve in the planned grinding path includes multiple sub-curves, and the multiple sub-curves include the circumferential segments of the multiple concentric circle paths in the bone area to be ground.

2. The method according to claim 1, characterized in that, determining the friction coefficient information between the bone to be removed and the end effector of the surgical robot system based on the bone mechanics information includes:

A pre-set first mapping relationship is obtained, and the bone biomechanical information of the bone to be removed is obtained based on the first mapping relationship and the image grayscale information of the bone medical image. The first mapping relationship is used to characterize the correspondence between image grayscale and bone biomechanical information.

A pre-set second mapping relationship is obtained, and the friction coefficient information between the bone to be removed and the end effector is determined based on the second mapping relationship and the bone mechanics information of the bone to be removed; the second mapping relationship is used to characterize the correspondence between the friction coefficient between the end effector and the bone and the bone mechanics information.

3. The method according to claim 1 or 2, characterized in that, determining the desired contact force between the end effector and the bone to be removed during the bone grinding process based on the friction coefficient information includes:

Based on the desired torque corresponding to the end effector and the structural parameters of the end effector, the desired friction force of the end effector under the desired torque is obtained;

By combining the desired frictional force and the friction coefficient information, the desired contact force between the end effector and the bone to be removed during the bone grinding process is obtained.

4. The method according to claim 1, wherein the radial spacing between the plurality of concentric circular paths is determined based on the image grayscale information of the bone medical image of the bone to be removed; wherein the radial spacing between the concentric circular paths in the high grayscale region is smaller than the radial spacing between the concentric circular paths in the low grayscale region, and the image grayscale value of the high grayscale region is greater than the image grayscale value of the low grayscale region.

5. A surgical robot system, characterized in that it comprises:

robotic arm;

An end effector, connected to the end of the robotic arm, is used to perform bone grinding operations under the drive of the robotic arm;

A controller, connected to the robotic arm, includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the method according to any one of claims 1 to 4.

6. The system according to claim 5, wherein the processor, when executing the computer program, further performs the following steps:

The current grinding information of the end effector during the bone grinding process of the bone to be removed is obtained, and the current grinding information includes the current position, current feedback force and current speed of the end effector;

The target position information of the end effector is determined by using the expected grinding information and the current grinding information of the end effector; the expected grinding information includes the expected position of the end effector, the expected contact force corresponding to the expected position, and the preset expected speed; the expected position is determined according to the planned grinding path;

The robot arm outputs motion commands based on the target position information of the end effector, and the robot arm is used to drive the end effector to perform bone grinding operations; the motion commands are used to indicate multiple sets of joint information that the robot arm needs to move.

7. The system according to claim 5, wherein the processor, when executing the computer program, further performs the following steps:

Acquire a three-dimensional image of the target object and the target pose information of the optical marker of the target object in the three-dimensional image;

The pose relationship between the optical markers of the end effector and the optical markers of the target object is acquired in real time using a vision camera.

Based on the target pose information and pose relationship of the target object, determine the end-effector pose information in the three-dimensional image of the optical marker of the end effector;

The three-dimensional model of the end effector is loaded into the three-dimensional image of the target object using the end effector pose information to determine the relative position of the end effector and the target object.

8. A computer device comprising a computer program, characterized in that, when executed by a processor, the computer program implements the steps of the method according to any one of claims 1 to 4.

9. The computer device according to claim 8, wherein the computer program, when executed by a processor, further performs the following steps:

10. The computer device according to claim 8, wherein the computer program, when executed by a processor, further performs the following steps: