JP2004345024A - Leg structure of a legged walking robot and a legged walking robot having the same - Google Patents

Abstract

An object of the present invention is to provide a foot structure of a legged walking robot and a legged walking robot that can perform sensing for posture control with a simple structure.
In a foot structure of a legged walking robot having a plurality of legs at the lower ends of two movable legs, each foot 17 includes a foot main body 37 connected to each movable leg, and a foot portion. The four pressure sensors 7S which are provided on the back surface of the main body 37 at a distance from each other and detect a foot reaction force applied to the back surface in a footwear state, respectively, and the four pressure sensors 7S are connected to a detector 74 serving as a detection end thereof. And a sole plate 17S whose lower surface constitutes a sole surface.
[Selection] Fig. 9

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a leg structure of a legged walking robot provided with a sensor and a legged walking robot provided with the same.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a foot structure of a legged walking robot of bipedal walking, a structure in which a six-axis force sensor (force sensor) is provided at an ankle portion in which each leg has six degrees of freedom (for example, see, for example). And Patent Document 1). In this legged walking robot, a force component in the X-axis direction, the Y-axis direction, and the Z-axis direction and a moment component in the X-axis direction, the Y-axis direction, and the Z-axis direction are measured by a six-axis force sensor, and each foot is measured. Is detected, and the magnitude (direction reaction force) and direction of the force applied to each movable leg are detected. The posture of the skeleton is appropriately controlled based on the detection result of the six-axis force sensor and the inclination and the angular acceleration detected by the inclination sensor on the body part side.
[0003]
[Patent Document 1]
JP-A-5-293776 (page 3, FIG. 1)
[0004]
[Problems to be solved by the invention]
Meanwhile, in a bipedal legged walking robot, the walking is controlled based on the ZMP model, and the walking is controlled such that the center of gravity is located within a projection plane connecting the contours of the soles of both feet. Two control methods of static walking are known. In static walking, posture control can be performed only by the detection results of the above-described six-axis force sensor. However, for example, in a lightweight robot, the measurement result becomes unstable due to the structure of the sensor, and sufficient calculation processing is performed. There are problems such as the need for abilities.
[0005]
An object of the present invention is to provide a leg structure of a legged walking robot that can perform sensing for posture control with a simple structure, and a legged walking robot including the same.
[0006]
[Means for Solving the Problems]
The foot structure of the legged walking robot of the present invention is a legged walking robot having a plurality of legs connected to the lower ends of the plurality of movable legs with a predetermined degree of freedom. A foot body connected to each movable leg, and a plurality of at least three feet provided on the back of the foot of the foot and spaced apart from each other to detect foot reaction forces applied to the back of the foot in a foot-wear state. And a pressure sensor.
[0007]
According to this configuration, at least three pressure sensors provided separately from each other on the sole surface of the foot detect a sole reaction force applied to the sole surface of the sole in a sole state. From the detection result, the approximate pressure (reaction force) distribution on the sole surface and the center point (center position) of the foot landing reaction force can be easily detected. Further, the center of gravity of the body on the ground contact surface can be detected from the center point of each foot landing reaction force in the plurality of feet.
[0008]
In this case, it is preferable that each pressure sensor has a detector that is grounded on the floor and constitutes a detection end, and the lower end of the detector is formed in a plate shape.
[0009]
By the way, the floor surface on which the feet touch the ground (footwear) is not uniformly flat. For example, in the case of footsteps or stairs of a door, the center of the sole surface of the foot may be grounded, and some pressure sensors may be in a non-grounded state. According to the above configuration, since the lower end portion of the detector of each pressure sensor has a relatively large area, it is possible to prevent as much as possible some of the pressure sensors from being in the non-ground state.
[0010]
Further, the foot structure of another legged walking robot of the present invention is a legged structure of a legged walking robot having a plurality of legs connected to a lower end of a plurality of movable legs with a predetermined degree of freedom, respectively. Each foot is provided with a foot main body connected to each movable leg, and at least three of which are provided separately from each other on the back surface of the foot main body and detect a foot reaction force applied to the back surface of the foot state. A plurality of pressure sensors and a plurality of pressure sensors are connected to each other at a detector serving as a detection end thereof, and a sole plate whose lower surface constitutes a sole surface is provided.
[0011]
According to this configuration, the foot landing reaction force is detected by the at least three pressure sensors on the back surface of the foot body, but the plurality of pressure sensors are connected to each other by the sole plate constituting the back surface of the foot. Therefore, the foot landing reaction force in this case is applied to the plurality of pressure sensors via the sole plate. Therefore, erroneous detection (including non-detection) of some pressure sensors due to unevenness of the floor surface (for example, footsteps or stairs) does not occur. Therefore, from the detection results of the plurality of pressure sensors, it is possible to easily and reliably detect the approximate pressure (reaction force) distribution on the sole surface and the center point (center position) of the foot landing reaction force. Further, the center of gravity of the body on the ground contact surface can be detected from the center point of each foot landing reaction force in the plurality of feet.
[0012]
In this case, it is preferable that four pressure sensors are provided, the sole surface of the sole plate is formed in a substantially rectangular shape, and the four pressure sensors are arranged at four corners of the sole plate.
[0013]
According to this configuration, the possibility of falling can be detected with high accuracy, and the arithmetic processing at that time can be easily performed.
[0014]
In these cases, it is preferable that the foot main body has a sensor holder that integrally holds the plurality of pressure sensors.
[0015]
According to this configuration, the plurality of pressure sensors can be unitized, and can be easily attached to the foot main body. It is preferable that the sensor holder is incorporated in a lower part of the foot main body.
[0016]
In these cases, each pressure sensor is preferably configured by a gas sensor.
[0017]
According to this configuration, even when the body of the legged walking robot is relatively lightweight, the response to the foot landing can be detected stably and accurately without impairing the response and the like.
[0018]
In this case, the gas sensor includes a sensor body, a pressure chamber connected to the sensor body, a sealing film body that hermetically seals a lower open end of the pressure chamber, and an abutment on the sealing film body from below to form the gas sensor. And a detector to be pressed and deformed.
[0019]
According to this configuration, when the sealing film is deformed due to the foot contact reaction force applied to the detector and the pressure in the pressure chamber changes, the sensor body senses the change. As described above, since the pressure chamber is hermetically sealed with the sealing film body and the sealing film body is deformed by the detector, the pressure can be accurately sensed with a simple structure.
[0020]
In this case, it is preferable to further include a return member that urges the sealing film body from the pressure chamber side to the reference posture.
[0021]
According to this configuration, when the pressure drops, the sealing film body can be forcibly restored, and accordingly, the sealing film body is made of a material and a thickness having good responsiveness. And the detection accuracy can be improved.
[0022]
In these cases, it is preferable that the detector be further slidably supported in the vertical direction and further include a regulating member that regulates the position of the lower moving end.
[0023]
According to this configuration, the restoration position of the sealing film body can be regulated via the detector, and the detector itself can be appropriately held.
[0024]
Further, a legged walking robot according to the present invention includes the leg structure of the legged walking robot described above. In this case, it is preferable to have two movable legs and two corresponding legs.
[0025]
According to this configuration, walking (bipedal walking) can be controlled by a simple control method using the plurality of pressure sensors provided on the foot body.
[0026]
In this case, based on the detection results of the plurality of pressure sensors, calculating means for obtaining the pressure distribution on the sole surface of each foot and obtaining the position of the center of gravity of the body in the horizontal plane from the respective pressure distributions on both feet, Posture control means for controlling the posture of the body based on the position of the center of gravity obtained in the step (a), wherein the posture control means comprises a virtual area connecting the soles of the feet with outlines in a standing motion in which both feet touch the ground. Therefore, the posture of the body is controlled so that the position of the center of gravity does not deviate, and in the walking motion from raising one foot to touching the ground, the position of the center of gravity is not deviated from the back of the foot of the other foot. It is preferable to control the attitude of the user.
[0027]
According to this configuration, in the standing motion, the posture is controlled so that the center of gravity does not deviate from the virtual region connecting the soles of the two feet with the outlines, and in the walking motion, the posture is controlled from the sole of the other leg. Since the posture is controlled so that the position of the center of gravity does not deviate, proper bipedal walking can be performed without falling. Moreover, since the control is easy, the responsiveness is improved and the walking speed can be increased.
[0028]
In this case, it is preferable that the posture control means controls the posture of the body so that the pressure values of the plurality of pressure sensors at each foot are substantially equal.
[0029]
According to this configuration, biped walking can be stably performed even when the floor surface has irregularities or inclination.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a legged walking robot according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. This legged walking robot is a bipedal walking small robot (about 30 cm tall), and is designed to perform so-called static walking in a walking operation.
[0031]
As shown in FIG. 1, this legged walking robot (hereinafter simply referred to as "robot") 1 has a head H1, a torso 10, a pair of arms (right arm R61, left arm L61) and a pair of support legs ( Hereinafter, simply “leg”: a right leg R11 and a left leg L11) are provided. As shown in FIG. 2, a main controller 20 which is a center of the control system is built in the torso 10, and the head H1, the right arm R61 and the left arm L61, the control units, the right leg R11 and the left Each control unit (right leg control unit R21, left leg control unit L21) of the leg L11 is connected via a bus (serial bus) H1B and 21B such as a USB. The robot 1 walks bipedally by alternately stepping on the right leg R11 and the left leg L11, which are a pair of legs, in consideration of the robot center point P. For this reason, for convenience of explanation, the following description will focus on the torso 10 and the leg 11 (right leg R11, left leg L11), and the description of the head H1, right arm R61, and left arm L61 will be omitted. Omitted as appropriate.
[0032]
The “robot center point” described above includes the meaning of ZMP (Zero Moment Point: a point on the floor where the moment due to the floor pressure becomes zero). In addition, the reference signs “R」 ”and“ L〜 ”indicate“ right ”and“ left ”, respectively, and hereinafter, for items common to the left and right,“ R ”and“ L ”are representatively shown. A description will be omitted. For example, the pair of legs described above are individually “right leg R11” and “left leg L11”, but items common to the left and right are described as “leg 11”. Also, the axes of the three degrees of freedom of the posture are a roll axis (R axis), a pitch axis (P axis), and a yaw axis (Y axis) as shown in FIG. In addition, as shown in FIG. 3B, there may be a case where a plurality of axes are used depending on the form of the actual structure (mechanical component). However, in this embodiment, regardless of the actual form (structure), As shown in FIG. 3C, the elements (mechanical components) of each axis are indicated by a single axis element, and the reference numerals are “〜R” (roll axis), “〜P” (pitch axis), and “ＰP” (pitch axis). ＹY ”(yaw axis).
[0033]
First, as shown in FIGS. 1 to 3, the leg 11 includes a hip joint (a hip joint drive unit) 12, a thigh 13, a knee joint (a knee joint drive unit) 14, and a neck 15. An ankle joint (ankle joint drive unit) 16 and a foot (foot, foot body) 17 are provided.
[0034]
As shown in FIGS. 1 to 3 and 5, the hip joint portion 12 includes a hip joint yaw axis 12Y, a hip joint roll axis 12R, a hip joint pitch axis 12P, and a hip joint drive / drive for detecting these and detecting each rotation angle. A detection unit 32, a hip joint control unit 42 for controlling these components, and a power transmission mechanism (not shown) for transmitting power to the thigh 13 (hereinafter, the “power transmission mechanism” is similarly omitted) are provided. I have.
[0035]
A hip joint yaw angle motor 2YM that controls the rotation angle (yaw angle) of the thigh portion 13 in a normal or reverse direction (movement) about the hip joint yaw axis 12Y; A hip joint yaw angle sensor (for example, a potentiometer) 2YS that detects an actual driven yaw angle, a hip joint roll angle motor 2RM that similarly drives the rotation angle (roll angle) of the hip joint roll shaft 12R, and a roll thereof A hip joint roll angle sensor 2RS for detecting the angle, a hip joint pitch angle motor 2PM for driving the rotation angle (pitch angle) of the hip joint pitch axis 12P so as to be controllable, and a hip joint pitch angle sensor 2PS for detecting the pitch angle. ing.
[0036]
The hip joint control unit 42 includes servo controllers 2YB, 2RB, and 2PB each having a CPU, ROM, RAM, and the like (not shown), and sensing controllers 2YC, 2RC, and 2PC having the same configuration, and a trunk unit via the bus 21B. The main controller 20 is connected to the main controller 20, and as a part of the leg control unit 21, controls each part in the hip joint 12 while cooperating with the main controller 20. Here, each of the servo controllers 2YB, 2RB, and 2PB controls the driving of each of the motors 2YM, 2RM, and 2PM based on the driving control data from the main controller 20, and each of the sensing controllers 2YC, 2RC, and 2PC The detection signals from the sensors 2YS, 2RS, and 2PS are output (reported) to the main controller 20 as detection control data.
[0037]
As shown in FIGS. 1 to 3 and 6, the knee joint 14 includes a knee joint pitch axis 14 </ b> P, a knee joint driving / detecting unit 34 that detects its driving and rotation angle, and a control unit for controlling these components. It includes a knee joint control unit 44 and a power transmission mechanism that transmits power to the neck 15. The knee joint drive / detection unit 34 includes a knee joint pitch angle motor 4PM that drives a controllable pitch angle for rotating (moving) the shin part 15 forward and reverse around the knee joint pitch axis 14P, and the pitch angle thereof. And a knee joint pitch angle sensor 4PS for detecting
[0038]
The knee joint control unit 44 is connected to the main controller 20 via the bus 21B similarly to the above-described hip joint control unit 42, and controls the driving of the motor 4PM based on the drive control data from the main controller 20 as described above. A servo controller 4PB; and a sensing controller 4PC which similarly outputs a detection signal from the sensor 4PS to the main controller 20 as detection control data. Each part in the joint 14 is controlled.
[0039]
As shown in FIGS. 1 to 3 and 7, the ankle joint 16 includes an ankle joint pitch axis 16 </ b> P, an ankle joint roll axis 16 </ b> R, and an ankle joint drive / detection unit that drives these and detects each rotation angle. 36, an ankle joint control section 46 for controlling these, and a power transmission mechanism for transmitting power to the foot section 17. The ankle joint drive / detection unit 36 includes an ankle joint pitch angle motor 6PM that drives a controllable pitch angle for rotating (moving) the foot unit 17 forward or reverse around the ankle joint pitch axis 16P, and the pitch thereof. An ankle joint pitch angle sensor 6PS for detecting the angle, an ankle joint roll angle motor 6RM for driving the roll angle of the ankle joint roll axis 16R so as to be controllable, and an ankle joint roll angle sensor 6RS for detecting the roll angle. , Is provided.
[0040]
The ankle joint control unit 46 is connected to the main controller 20 via the bus 21B similarly to the above-described hip joint control unit 42 and the like, and controls the driving of each of the motors 6PM and 6RM based on the drive control data from the main controller 20. A servo controller 6PB and 6RB similar to those described above, and sensing controllers 6PC and 6RC which similarly output detection signals from the sensors 6PS and 6RS to the main controller 20 as detection control data. In cooperation with the main controller 20, each part in the ankle joint 16 is controlled.
[0041]
As shown in FIGS. 1 to 3 and FIGS. 8 to 11, the foot portion 17 is fixed to the lower side of the foot portion 17 and formed in a sole plate 17 </ b> S formed substantially in a square shape corresponding to the planar shape of the lower surface. And a sole detection unit (sole sensor unit) 37 for detecting the state of the sole plate 17S, and a sole control unit 47 for performing control based on the detection result.
[0042]
The sole detection unit 37 is composed of a gas sensor, and the front left (LF), the front right (RF), and the rear left (RF) of the sole plate 17S in the traveling direction (walking direction: the direction of the thick arrow (←) in the drawing). LB) and four pressure sensors 7LFS, 7RFS, 7LBS and 7RBS (hereinafter, referred to as "pressure sensor 7S" when the sensors are collectively referred to without distinction) for detecting the ground pressure at the rear right (RB) and four pressure sensors A box-shaped sensor holder 51 also serving as a 7S storage case. The four pressure sensors 7S are arranged at four corners of the sole detecting section 37 formed in a substantially rectangular shape in plan view so as to be separated from each other.
[0043]
The four (gas) pressure sensors 7S in the embodiment are symmetrical with respect to the center line of the sole plate 17S, and are arranged such that the lines connecting the center axes thereof form a rectangle. This may be arranged so as to form a trapezoid. Instead of this, it is constituted by three pressure sensors 7S which are symmetrical with respect to the center line of the sole plate 17S and which are arranged so that the lines connecting the center axes thereof form an isosceles triangle. Is also good.
[0044]
The sensor holder 51 includes a case-shaped holder main body 52, a top plate 53 provided above the holder main body 52, and a bottom plate 54 provided below the holder main body 51. Four sensor housings 52a for housing the pressure sensors 7S are formed. Four bosses 53a project from the lower surface of the top plate 53 so as to be disengaged from the four sensor housings 52a. Screws for fixing the sole detecting section 37 are screwed into the bosses 53a from above. It is supposed to. The bottom plate 54 has four guide holes (through holes) 54a through which the detectors 74 of the four pressure sensors 7S pass.
[0045]
Each pressure sensor 7S includes a sensor main body 71, a pressure chamber 72 connected to the lower side of the sensor main body 71, a sealing film 73 for hermetically sealing a lower open end of the pressure chamber 72, and a sealing film 73. And a detector 74 that abuts from below and presses and deforms it. In addition, a return member 55 including a return spring (coil spring) 55a and a backing plate 55b is provided above the sealing film body 73 to urge the deformed sealing film body 73 back to the reference posture. .
[0046]
When the pressure of the detector 74 (footwear reaction force) acts, the detector 74 moves upward and presses and deforms the sealing film 73 against the spring force of the return member 55. Due to this deformation, the pressure chamber 72 contracts and the internal pressure increases, and the sensor main body 71 detects this pressure. When the pressure applied to the detector 74 decreases from this state, the backing plate 55b is pushed by the return spring 55a, and the sealing film 73 and the detector 74 return (restore) to the original reference posture.
[0047]
The sensor body 71 is obtained by processing a silicon 75a into a diaphragm structure, and housing a chip 75 in which a gauge sensor 75b based on piezo resistance or the like is formed in a package 76 of a glass substrate connected to the pressure chamber 72. The projecting portion 76b of the package 76 having the communication hole 76a is fitted (airtightly bonded) to the opening connected to the pressure chamber 72 so as to face the pressure chamber 72.
[0048]
The main part of the pressure chamber 72 is constituted by the above-mentioned sensor housing part 52a, and the above-mentioned return spring 55a is housed in a downward upward annular groove 55c formed on the top surface. An upwardly directed lower annular groove 55d for receiving the return spring 55a is formed on the upper surface of the circularly shaped contact plate 55b. That is, the return spring 55a receives the upper annular groove 55c and urges the contact plate 55b downward via the lower annular groove 55d. The sealing film 73 is a circular film made of silicon rubber or the like, and is hermetically bonded to the lower surface of the holder main body 52 so as to close the lower open end of the pressure chamber 72.
[0049]
The detector 74 includes a circular plate portion 74a that comes into contact with the sealing film body 73, and a shaft portion 74b that extends downward from the circular plate portion 74a, and has a substantially “T” -shaped cross section. The shaft portion 74b is vertically slidably engaged with the through hole 54a of the bottom plate 54, and the upper surface of the bottom plate 54 corresponding to the edge of the through hole 54a is the lower end of the detector 74. The position is regulated. That is, the detector 74 comes into contact with the upper surface of the bottom plate 54 in a state where the sealing film body 73 has returned to the horizontal reference posture. The lower end of the shaft portion 74b is formed in a hemispherical shape, and the detector 74 is adhered or screwed and fixed to the sole plate 17S at this lower end (the illustrated one is "screwed").
[0050]
The sole plate 17S is made of a thick resin plate or a metal plate, and although not shown in the drawing, a non-slip sheet is attached to a lower surface of the sole surface, or a non-slip process is performed. It has been subjected. Circular shallow grooves 17Sa are formed at four corners on the lower surface of the sole plate 17S, and fixing screws 17Sb screwed to the detectors 74 of the pressure sensors 7S are provided at the center positions of the respective shallow grooves 17Sa. ing. That is, the sole plate 17S is provided so as to interconnect the four pressure sensors 7S.
[0051]
As described above, since the four pressure sensors 7S provided on the back surface of the foot portion 17 are connected by the sole plate 17S, the reaction force (ground pressure) from the floor surface at the time of putting on the foot is four. It can be detected as the sum of the pressure values of the pressure sensors 7S, and by comparing the pressure values of the four pressure sensors 7S, the inclination of the body can be detected. Further, the center of gravity position (robot center point) P in the horizontal plane can be detected from the detection results of the four pressure sensors 7S of each of the foot portions 17.
[0052]
In the present embodiment, the sole detection unit 37 and the sole plate 17S are configured separately. However, the sole plate 17S may be omitted integrally. In such a case, it is preferable that the lower end of the detector 74 is formed in a flat plate shape, and the contact area of each detector 74 is increased. Further, in the embodiment, the gas sensor is used as the pressure sensor 7S, but the type of the sensor is not limited as long as it can detect the sole reaction force (ground pressure).
[0053]
Next, as shown in FIGS. 1 to 3, the arm portion 61 (the right arm portion R61 and the left arm portion L61) includes a shoulder joint roll shaft 61R for rotating the arm portion 61 in the roll direction with respect to the body portion 10. , A shoulder joint yaw axis 61Y for rotating in the yaw direction, and an arm drive / detection unit (including a shoulder joint roll drive mechanism, a shoulder joint yaw drive mechanism, a sensor for each rotation angle, etc.) (not shown) for driving them And an arm control unit (not shown) for controlling each unit in the arm 61 in cooperation with the main controller 20 of the trunk 10 connected via the bus H1B, and a power for operating each unit in the arm 61 And a power transmission mechanism (not shown) for transmitting the power.
[0054]
The head H1 includes various sensors and various drivers (not shown) for light (image) and sound (vibration) for simulating the functions of the human head such as eyes, nose, and mouth. ), A head control unit (not shown) for controlling each unit in the head H1 in cooperation with the main controller 20 connected via the bus H1B, and power to each unit (eyes, mouth, etc.) in the head H1. And a power transmission mechanism (not shown) for transmitting the power.
[0055]
Further, the body 10 includes a main controller 20, a power supply unit (not shown), and a power transmission mechanism (not shown) for transmitting power to each part in the body 10.
[0056]
The main controller 20 includes a CPU 210, a ROM 220, a RAM 230, and a peripheral control circuit (Peripheral Controller: hereinafter, “P-CON”) 240, and is connected to each other by an internal bus 20B. The ROM 220 has a control program area 221 for storing a control program to be processed by the CPU 210, and a control data area 222 for storing control data such as specification data and reference data which are the basis (reference) of control of each unit.
[0057]
The RAM 230 has a control table area 231 and an information table area 232, and is used as a work area for various processes. In the control table area 231, the servo controllers of the respective control units in the robot 1 (for example, the servo controllers R2YB and the like described above in FIG. 5; hereinafter, the servo controllers RB and LB are collectively referred to as “servo controllers” SBC ”) is stored. The information table area 232 includes a sensing controller of each control unit in the robot 1 (for example, the sensing controller R2YC or the like described above with reference to FIG. 5; Sensing controller SSC ”), the current state information table (current table: read table: current data) based on the detection control data input (reported) from An information table such as a target state information table (target table: move table: target data) is stored.
[0058]
The P-CON 240 includes a logic circuit for complementing the function of the CPU 210 and performing an interface (bus interface) with each control unit in the robot 1 and a functional circuit such as a timer for performing various clocks. It is configured and incorporated. For this reason, the P-CON 240 takes in the detection control data from the sensing controller SSC of each part as it is or processes it and takes it into the internal bus 20B, and in conjunction with the CPU 210, the drive control data output from the CPU 210 or the like to the internal bus 20B. Is output as it is or processed to the servo controller SBC of each unit.
[0059]
Then, the CPU 210 inputs detection control data from each unit via the P-CON 240 based on the control program and control data in the ROM 220, and controls the target value and the control value for the target value from the current value indicated by the control program and the control data in the ROM 220. Various values are processed, such as retrieving values and rewriting control tables and information tables in the RAM 230, and drive control data is output to each unit via the P-CON 240, thereby controlling the entire robot 1. .
[0060]
Next, a processing flow of the entire control of the robot 1 will be described with reference to FIG. The processing flow of this processing and various processing described below includes not only software (including programs: firmware) but also a part or all of which is executed by hardware (logic circuit, functional circuit, etc.). Shall be included.
[0061]
As shown in the figure, when the process (S0) is started by turning on the power or the like, first, predetermined initial settings are appropriately performed (S1), and then various interrupts regulated by various priorities are permitted. (S2) The state is maintained as it is until some interruption occurs (S3: No), and if any interruption occurs (S3: Yes), the process proceeds to each interruption processing (S4). When the interrupt processing is completed, the state is maintained again (S3: No).
[0062]
For example, as shown in FIG. 13, the (forward) walking is instructed to the robot 1 that is currently “still” by voice recognition by utterance such as “forward” with respect to the head H1, operation of a remote controller, or operation of a predetermined switch. Then, a (forward) walking instruction interrupt occurs, the (forward) walking process (S10) is started, the process proceeds to the (forward) walking program (S11), and the process (S10) ends (S12). ).
[0063]
In this case, for example, a control program for walking processing (walking program) may be loaded instead of the control program for static processing or the like up to that time, or an address of the walking program may be specified (for example, The processing mode may be switched (by setting (ON) or the like). As a result, the processing (response) of the robot 1 to various interrupts as a whole conforms to “walking”. The state transition (transition of the control mode or the control target period) during the execution of the walking program is as shown in FIG.
[0064]
In addition to the above-described example of the forward walking process, various examples of various processes that can be started, such as the backward progressing line process, can be considered. For example, a sensor capable of detecting (monitoring) an obstacle or the like in front by a laser beam or the like is provided as a function of the eyes of the head H1 or the like, and a stationary process (stationary program) is started by an interrupt generated by the obstacle detection. Or, after that, check the surroundings (left and right, etc.) while the vehicle is still, and start the direction change process according to the check detection result (interruption due to), and after confirming it after the direction change process Various types of control programs that can be started, such as starting the walking process again, and methods of starting the control programs can be considered and can be realized.
[0065]
Further, in the robot 1, as shown in FIG. 14, for example, a periodical control is performed by a control synchronous trigger based on a frequency-divided signal of a clock signal (in the case of a small size like the robot 1, a period of about 1 ms or less is desirable). When an interrupt occurs, the state detection / target setting process (S20) is started. First, detection control data is input from all the sensing controllers SSC to obtain all sensor detection results, and the above-described current state table in the RAM 230 is input. (S21), based on the rewritten current state table and the control program at that time (for example, the above-described walking program), derives the next target value by calculation or table reference, and rewrites the target table (target value Setting), derive a control value to match the target value from the current value in the current table and the target value in the target table Te, performs rewriting of the control table (control value deriving) (S22).
[0066]
Next, in order to output (instruct) all servo (all joint) control values, drive control data indicating the values (control values) of the control table are output to all servo controllers SBC (S23), and the process (S20) ) Is ended (S24).
[0067]
The example of the above-described processing (S20) is an example of performing a periodic control processing, that is, the main controller 20 and each servo controller SBC and each sensing controller SSC are periodically (periodically) synchronized with a clock or the like. This is an example in which the entire robot 1 is controlled by performing communication between the robots (hereinafter, “communication between controllers”). However, control processing can be performed irregularly (asynchronously).
[0068]
In this case, for example, as in the illustrated process (S30), when a change is detected by a sensor of each unit in the robot 1 and an individual detection interrupt is generated for each sensor, the individual detection / target setting process (S30) is performed. In order to obtain the detection result by the sensor that has been activated and that has caused the interruption, the detection control data is input from the sensing controller SSC in charge of the sensor, and the above-described current state table is rewritten (S31). Based on the control program, target value setting (target table rewriting) and control value derivation (control table rewriting) are performed (S32: same as S22).
[0069]
In the above description, all servo (all joints) control value output (S23) is performed. However, as shown by a dotted line, there is a difference between the current value of the current table and the target value of the target table. In other words, only those which need to be changed (operated) to a state different from the current state are extracted (S33), and only the drive control data indicating the value (control value) of the corresponding control table is converted to the corresponding servo controller SBC. Only the output (S34) may be performed, so that the communication between controllers can be made more efficient and shorter, for example, when there is little difference.
[0070]
In the above-described target value setting / control value deriving process (S22 or S33), for example, as shown in FIG. 15, when the process (S40: subroutine for S22 or S32) is started, first the sole pressure is set. An averaging (derivation) process is performed (S41).
[0071]
In addition, for example, if the processing (control) is executed according to the control value derived in the “foot sole pressure averaging (derivation) processing (S41)”, “foot sole pressure averaging” can be performed. In (S40), since setting of the target value and derivation of the control value are performed, all processes described below are derivation processes (in this sense, “derivation” is written in parentheses).
[0072]
Also, in the following, for convenience of description (efficiency), the sole left front sensor L7LFS, the sole right front sensor L7BFS, the sole left rear sensor L7LBS, and the sole right rear sensor L7BFS of the left foot part L17 are represented by a sensor {circle around (1)}. , {Circle around (2)}, {circle around (3)} and {circle around (4)}, and similarly, the sensors R7LFS to R7BFS for the right foot portion R17 are referred to as sensors {circle around (5)} to {8} (see FIG. 17 and the like). Further, the center of gravity (center of gravity projected on the floor surface: the same applies hereinafter) obtained only from the contact pressure (floor reaction force) detected by the left foot L17 alone is defined as the center of gravity of the left foot (the center of gravity of the left foot) LP, and the target of the center of gravity of the left foot LP The point is defined as a left foot target point (left foot center point, left foot center of gravity target point) LD, similarly, the center of gravity of the right foot portion R17 is defined as a right foot center of gravity (right foot center of gravity point) RP, and the target point is defined as a right foot target point (right foot center point, right foot center of gravity). The center of gravity of the entire robot 1 is referred to as the robot center point (center of gravity, center of gravity point) P, and the target point is set as the target point (center of gravity target point) D.
[0073]
Here, for example, as shown in FIG. 16, the output value (detection value: pressure value) of the sensor (1) of the left foot is 100 (unit is omitted: hereinafter, shown as "1" = 100). In the case of (2) = 200, (3) = 200, and (4) = 400, the sum total is ((1) + (2) + (3) + (4) =) 900, and at present, the sum of the figures shown in FIG. 1) The left foot center of gravity point LP is located at a position close to (4) on the diagonal line connecting (4), but when all the detected values (1) to (4) match the average value 225, the left foot target point is reached. In this case, in the above-described foot sole pressure averaging (deriving) process (S41), the left foot target point LD is set as the target value, and the current value of the left foot center of gravity point LP is set in the direction of the arrow shown in the drawing. A control value to be moved to match the left foot target point LD is obtained by calculation or referring to a table (derived). .
[0074]
More specifically, only the difference before and after, that is, the difference between the sum of (1) and (2) and the sum of (3) and (4) ((1) + (2))-((3) + A control value for rotating the ankle joint pitch axis L16P is derived by an amount that cancels (cancels) (4))). This value becomes the original value of the drive control data for driving the ankle joint pitch angle motor L6PM via the servo controller L6PB. Similarly, a control value for rotating the ankle joint pitch axis L16R by the offset of the difference between the left and right ((1) + (3)-((2) + (4))) is derived. And the original value of drive control data for driving the ankle joint roll angle motor L6RM via the servo controller L6RB.
[0075]
Then, by performing the same operation as described above for the right foot sensors (5) to (8), a control value for matching the right foot center of gravity point RP to the right foot target point RD for the right flat foot R17 is derived. .
[0076]
When the above sole pressure averaging (deriving) processing (S41) is completed, as shown in FIG. 15, when the vehicle is stationary (that is, when the control program currently being processed is a stationary program or when the processing mode is the stationary mode), as shown in FIG. Is determined) (S42), and when it is stationary (S42: Yes), the posture stabilization (derivation) process is performed (S43), and the process (S40) ends. (S44).
[0077]
Here, for example, as shown in FIG. 17, the substantially square points on the lower surface of the left foot part L17 are denoted by a to d, and the respective points of the right foot part R17 are denoted by e to h. Inside a virtual area A of a polygon connecting outer corners a, b, f, h, g, and c (a polygon connecting abffhcc: sole of foot + shaded area), If there is an entire center of gravity point (robot center point) P, the center of gravity does not fall, but the center of gravity when the posture is most stable (that is, the ideal center of gravity point) generally connects the illustrated left foot center of gravity LP and the right foot center of gravity RP. Since this point corresponds to the center (center) of the line N, this point is referred to as a target point (centroid target point) D. The same applies to the case where the right foot is forward (see FIG. 20 and the like).
[0078]
Therefore, the center of gravity of the left foot L17 and the center of gravity of the right foot R17 are located at the center of gravity of the left foot LP and the center of gravity of the right foot RP shown in FIG. 17 by the above-described sole pressure averaging (derivation) processing (S41). Assuming that the sum of the outputs of the left foot sensors (1) to (4) is 900 ((1) + (2) + (3) + (4) =) 900, the right foot sensors (5) to (8) In the case of (5) + (6) + (7) + (8) =) 1800, the robot center point P is generally offset to the right foot side on the line N as shown in FIG. In this case, in the above-described posture stabilization (derivation) process (S43), the robot center point P, which is the current value, is made coincident with the center-of-gravity target point D as the target value (P43). Is moved in the direction of the arrow to coincide with D), and a control value for obtaining the state shown in FIG. This value is the original value of the drive control data instructed to each servo controller SBC for controlling each joint of each part in the robot 1 (particularly each part in the leg 11).
[0079]
Further, as shown in FIG. 15, when the vehicle is not stationary (S42: No), next, when walking forward (that is, when the control program currently being processed is the forward walking program or when the processing mode is the forward walking mode). And the like (S45), and when it is not the time of forward walking (S45: No), other processing (target value setting / control value derivation in another processing mode) according to the control program or processing mode at that time. After performing the processing (S46) (S46), the processing (S40) ends (S44).
[0080]
Further, when the user is walking forward (S45: Yes), the foot is in a stable state (the state of (t1) or (t4) in FIG. 13: that is, while walking; Period: see FIG. 17 or FIG. 20) (S51), and if the foot is in a stable state (S51: Yes), the posture stabilization (derivation) process is performed as in the above-mentioned stationary state. (S43), the process (S40) ends (S44).
[0081]
Also, although it is a time of forward walking (S45: Yes), but not in a stable state of both feet (S51: No), next, the transition to the center of gravity (the state of (t2) or (t5) in FIG. 13: that is, there is no center of gravity) It is a period in which the center of gravity is shifted to the other foot with the other foot as an axis foot in order to step forward on one foot, and it is determined whether or not the center of gravity shift period for quiet walking) (S52). At some point (S52: Yes), it is next determined whether or not the center of gravity of the left foot (that is, the center of gravity is shifted to the left foot to make the left foot an axis foot) (S53), and the center of gravity of the left foot (state of (t2)) is determined. If there is (S53: Yes), the left foot center of gravity shift (derivation) process is performed (S54), and the process (S40) ends (S44).
[0082]
In the left foot center-of-gravity shift (derivation) process (S54), the left foot center-of-gravity point LP is set as the center-of-gravity target point D, for example, as shown in FIG. That is, for example, when the right foot on the opposite side is stepped on, in order not to fall over statically, the entire weight is placed on the left foot and the area of the sole (in the drawing, the substantially square ab on the lower surface of the left foot L17) is shown. If the center of gravity (robot center point) P is within the range enclosed by −cd, the robot will not fall down, but the ideal center of gravity as the posture is most stable is the left foot center of gravity LP. A control value for moving the robot center point P in the direction of the arrow to match the center of gravity target point D (left foot center of gravity point LP) is derived, and the servo controller SBC controls each joint such as each part in the leg 11. Is the original value of the drive control data.
[0083]
Further, as shown in FIG. 15, when the center of gravity of the left foot is not present (the state of (t5) in FIG. 13) (S53: No), the same as the above-described shift (derivation) processing of left center of gravity (S54), but the right foot Is performed (S55), and the process (S40) ends (S44).
[0084]
When it is not the transition period to the center of gravity (S52: No), it is determined that it is the one foot step (the state of (t3) or (t6) in FIG. 13), and then the center of gravity of the left foot (that is, the right foot with the left foot as the axial foot). Is determined (S56), and when the center of gravity of the left foot (state at (t3) in FIG. 13) (S56: Yes), right foot stepping (derivation) processing is performed (S57). The process (S40) ends (S44).
[0085]
In the right foot stepping (deriving) process (S57), for example, as shown in FIG. 19, only the right foot target point RD is used in order to step on the opposite right foot while keeping the left foot center of gravity LP as the center of gravity target point D. Is moved forward, and the control value for moving the right foot center of gravity RP in the direction of the arrow to match the right foot target point RD while keeping the robot center point P at the center of gravity target point D (left foot center of gravity point LP). Is derived and used as the original value of the drive control data for controlling each joint of each unit.
[0086]
Further, as shown in FIG. 15, when the center of gravity of the left foot is not present (the state of (t6) in FIG. 13) (S56: No), the same as the above-described right foot stepping (deriving) process (S54), but the right foot After performing the left foot stepping (deriving) process of stepping on the left foot with the center of gravity (axial foot) (S58), the process (S40) ends (S44).
[0087]
Then, for example, at the time when the above-described right foot stepping (deriving) process is completed in FIG. 19 (when the state at (t3) in FIG. 13 is completed), the state shifts to the two-foot stable period (state at (t4)). As described above, when both feet are stabilized (S51: Yes), as shown in FIG. 15, for example, as shown in FIG. 20, after performing the same posture stabilization (derivation) process as described above (S43), the process (S40) Is completed (S44). Of course, after this state (the state of (t3)), the same processing as the processing described above with reference to FIGS. 18 to 20 is performed on the opposite leg (by the state transition of (t4) to (t1)), The process of two-legged walking is performed.
[0088]
By the way, the floor surface on which the feet touch the ground (footwear) is not uniformly flat. For example, in the case of a footstep or a staircase of a door, a part of the sole surface may be in a ground state and another part may be in a non-ground state. For example, as shown in FIG. 21, when one sensor 7S is provided at each of the positions P1 and P2 in the cross section of the left foot portion L17, each pressure sensor 7S is independently provided without the sole plate 17S. In this case, even if the user presses on the projection T on the floor corresponding to another position, for example, the position P3 shown in the drawing, it cannot be detected unless it touches each pressure sensor 7S.
[0089]
On the other hand, in the robot 1, since the plurality of pressure sensors 7S are connected to each other with the sole plate 17S, when the protrusions T are stepped on, the respective pressure sensors 7S move the position P3 of the protrusion T from the position P3. Can be detected in inverse proportion to the distance L1 and the distance L2. Therefore, some of the pressure sensors 7S are not erroneously detected (including non-detection) due to irregularities on the floor surface (for example, footsteps or steps).
[0090]
Further, in this case, the detected values are averaged by the sole pressure averaging (deriving) process (S41) described above with reference to FIG. 15, and the left foot target point LD equidistant from both the position P1 and the position P2 is obtained. When the left foot center of gravity LP is matched in the same manner as described above, the actual center of gravity is not the left foot target point LD (the left foot center of gravity LP), but the temporary center of gravity Q equidistant from both the illustrated positions P3 and P2. Matches. In this case, the polygon including the protrusion T and one point that touches the floor surface becomes a temporary sole, and the temporary center of gravity Q becomes a point that is more stable than the left foot target point LD. The (derivation) process (S41) is a process (substitute) for stabilizing the actual center of gravity by making the actual center of gravity coincide with the ideal temporary center of gravity Q. For this reason, it is hard to be influenced by the protrusion T on the floor surface or the like, and it is possible to secure a proper bipedal walking without falling.
[0091]
As described above, when the robot 1 is stationary (standing motion), the posture is controlled so that the robot center point (center of gravity) P does not deviate from the virtual area A connecting the soles of both feet with outlines, At the time of walking (walking motion), the posture is controlled so that the robot center point P does not deviate from the sole surface of the foot serving as the axial foot, so that proper bipedal walking without falling down is possible. In addition, since the control is easy, the responsiveness is improved and the walking speed can be increased. Further, since the posture of the body is controlled so that the pressure values of the plurality of pressure sensors 7S at each foot (foot portion) 17 become substantially equal, even if the floor surface has unevenness or inclination, biped walking is not possible. It can be performed stably. Of course, other changes can be made as appropriate without departing from the scope.
[0092]
【The invention's effect】
According to the foot structure of the legged walking robot of the present invention, it is possible to easily detect the center point of each foot contact reaction force in the plurality of feet and the center of gravity of the body on the ground contact surface from the detection results of the plurality of pressure sensors. Based on this, the posture control of the body can be easily performed.
[0093]
According to the foot structure of another legged walking robot of the present invention, the center point of each foot landing reaction force in the plurality of feet and the contact point can be obtained from the detection results of the plurality of pressure sensors detected via the sole plate. The position of the center of gravity of the body on the ground can be reliably and easily detected. Thereby, the posture control of the body can be easily and appropriately performed.
[0094]
According to the legged walking robot of the present invention, walking (bipedal walking) can be controlled by a simple control method, and a low-cost and highly stable robot can be provided.
[Brief description of the drawings]
FIG. 1 is an overall perspective view of a legged walking robot according to an embodiment of the present invention.
FIG. 2 is a schematic block diagram showing a control system of the robot shown in FIG.
FIG. 3 is a schematic view of a degree of freedom configuration model of the robot shown in FIG. 1;
FIG. 4 is an explanatory diagram of a premise of a degree of freedom configuration model of FIG. 3;
FIG. 5 is a detailed block diagram of a hip joint of the robot of FIG. 2;
FIG. 6 is a detailed block diagram of the knee joint similar to FIG. 5;
FIG. 7 is a detailed block diagram similar to FIG. 5 of an ankle joint;
FIG. 8 is a detailed block diagram of the foot portion, similar to FIG.
FIG. 9 is a structural diagram showing a foot portion and a sole plate of the robot of FIG. 1;
FIG. 10 is an exploded perspective view of the foot portion and the sole plate of FIG. 9;
FIG. 11 is an enlarged sectional view of the foot portion of FIG. 9 around a pressure sensor.
FIG. 12 is a flowchart illustrating a schematic process of the entire control of the robot in FIG. 1;
FIG. 13 is a flowchart of (forward) walking processing and an explanatory diagram of a state transition under activation thereof.
FIG. 14 is a flowchart of a state detection / target setting process by a periodic control interrupt and an individual detection / target setting process by an irregular individual detection interrupt;
FIG. 15 is a flowchart of a target value setting / control value deriving process of FIG. 14;
FIG. 16 is an explanatory diagram schematically showing the principle of the sole pressure averaging derivation process of FIG.
17 is an explanatory diagram schematically showing the principle of the posture stabilization deriving process of FIG. 15 when the state transition at the time of standing still or the forward walking in FIG. 13 is a two-foot stable period before the left foot.
18 is an explanatory diagram similar to FIG. 17 of the left foot barycenter shift derivation process of FIG. 15;
FIG. 19 is an explanatory diagram similar to FIG. 17, illustrating the right foot step derivation process of FIG. 15;
FIG. 20 is an explanatory diagram similar to FIG. 17 when the state transition is a two-foot stable period before the right foot after stepping on the right foot.
FIG. 21 is an explanatory diagram showing an advantage of connecting a plurality of pressure sensors by a sole plate.
[Explanation of symbols]
1 robot (legged walking robot)
10 torso
11 (R11, L11) ... leg (right leg, left leg)
12 (R12, L12) ... hip joint (right, left)
13 (R13, L13) ... thigh (from right to left)
14 (R14, L14) ... Knee joint (right, left)
15 (R15, L15) ... Neck (from right to left)
16 (R16, L16) ... Ankle joint (right, left)
17 (R17, L17) ... Foot area (right to left)
17S (R17S, L17S) ... sole plate (right, left)
20 Main controller
20B, 21B, H1B ... bus
21 (R21, L21) ... leg control unit (right to left)
51 Sensor holder
54 Bottom plate (restriction member)
55 Return member
61 (R61, L61) ... arm (right to left)
(1)-(8), 7S, R7-S, L7-B ... (Sole sole) pressure sensor
71 Sensor body
72 pressure chamber
73 sealing film
74 detector
A virtual area
D (RD, LD) …… Target point of center of gravity (right foot ~ left foot ~)
H1 head
P Robot center point
RP, LP… Right foot center of gravity, left foot center of gravity
R-P, L-P Pitch axis
R-PM, L-PM Pitch angle motor
R-PS, L-PS Pitch angle sensor
R-R, L-R ...... Roll axis
R to RM, L to RM Roll motor
R-RS, L-RS Roll angle sensor
RY, LY Yaw axis
R ~ YM, L ~ YM ...... Yaw angle motor
R to YS, L to YS ... Yaw angle sensor
SBC, RB, LB ...... Servo controller
SSC, RC, LC, Sensing controller

Claims (13)

In a foot structure of a legged walking robot having a plurality of feet connected to a lower end of a plurality of movable legs with a predetermined degree of freedom, respectively,
Each said foot,
A foot body connected to each of the movable legs,
A plurality of pressure sensors provided at a distance from each other on the sole surface of the sole body and detecting at least three reaction forces applied to the sole surface in the sole state. The leg structure of a legged walking robot. Each of the pressure sensors has a detector that is grounded on the floor and constitutes a detection end,
The foot structure of a legged walking robot according to claim 1, wherein a lower end of the detector is formed in a plate shape. In a foot structure of a legged walking robot having a plurality of feet connected to a lower end of a plurality of movable legs with a predetermined degree of freedom, respectively,
Each said foot,
A foot body connected to each of the movable legs,
A plurality of pressure sensors provided at a distance from each other on the back surface of the foot portion main body and detecting at least three reaction forces applied to the back surface in a footwear state,
A foot structure for a legged walking robot, comprising: a plurality of pressure sensors connected to each other at a detector serving as a detection end thereof; and a sole plate having a lower surface forming a sole surface. It has four pressure sensors, and the sole surface of the sole plate is formed in a substantially square shape,
The foot structure of a legged walking robot according to claim 3, wherein the four pressure sensors are arranged at four corners of the sole plate. The foot structure of a legged walking robot according to any one of claims 1 to 4, wherein the foot body has a sensor holder that integrally holds the plurality of pressure sensors. The foot structure of a legged walking robot according to any one of claims 1 to 5, wherein each of the pressure sensors comprises a gas sensor. The gas sensor includes a sensor main body, a pressure chamber connected to the sensor main body, a sealing film body for hermetically sealing a lower open end of the pressure chamber, 7. A foot structure for a legged walking robot according to claim 6, further comprising a detector for pressing and deforming the legged walking robot. The foot structure of a legged walking robot according to claim 7, further comprising a return member for urging the sealing film body from the pressure chamber side to a reference posture. The legged walking robot according to claim 7 or 8, further comprising a regulating member that supports the detector so as to be slidable in the vertical direction and that regulates a position of a lower end of the detector. Foot structure. A legged walking robot comprising the leg structure of the legged walking robot according to claim 1. 11. The legged walking robot according to claim 10, comprising two movable legs and two corresponding legs. Based on the detection results of the plurality of pressure sensors, while calculating the pressure distribution on the sole surface of each foot, from the pressure distribution of each of the two feet, computing means to determine the center of gravity of the body in a horizontal plane, Posture control means for controlling the posture of the body based on the position of the center of gravity determined by the calculation means,
The posture control means, in a standing motion in which the two feet touch the ground, from a virtual area connecting the soles of the two feet with outlines, controls the posture of the body so that the center of gravity does not deviate,
Further, in a walking motion from raising one of the feet to touching the ground, the posture of the body is controlled so that the position of the center of gravity does not deviate from the sole surface of the other foot. 12. The legged walking robot according to item 11. 13. The legged walking robot according to claim 12, wherein the posture control means controls the posture of the body so that the pressure values of the plurality of pressure sensors at each of the feet become substantially equal.

Images