JP2005022040A - Walking robot correcting positional deviation, and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that an actual walking locus deviates from a walking locus specified by gait data due to the occurrence of a slip on a floor because flexure is generated to a walking robot. <P>SOLUTION: This walking robot is provided with a gait data storage means 46; a joint angle group computing means 58 for computing a joint angle based on gait data; an actuator driving means 60 for adjusting to the joint angle computed by the joint angle group computing means; devices 4, 52, 54 for detecting the positions of a grounding foot; a device 56 for computing deviation between a position in which the grounding foot should be and a position in which the grounding foot is; and a device 48 for correcting subsequent gait data with the computed deviation. The robot continues walking while changing the relative attitude of a left leg link, the waist and a right leg link according the corrected gait data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a mechanical system comprising a left leg link, a waist and a right leg link, and a left leg link and a right leg link utilizing a plurality of joints existing in the mechanical system. The present invention relates to a control technology for a robot that walks by changing the relative posture of the robot.
[0002]
2. Description of the Related Art Robots have been developed that walk by changing the relative postures of the left leg link, the waist, and the right leg link. Usually, the waist and left upper thigh are connected by the left hip joint, the left upper thigh and the left lower thigh are connected by the left knee joint, the left lower thigh and the left toe are connected by the left ankle joint, and the waist and the right upper thigh are connected by the right hip joint. The right upper leg and the right lower leg are connected by the right knee joint, and the right lower leg and the right foot are connected by the right ankle joint. The mechanical system composed of the left leg link, the waist, and the right leg link has multiple joints. By using these joints, the relative posture of the left leg link, the waist, and the right leg link is changed. be able to.
[0003]
When the relative postures of the left leg link, the waist, and the right leg link are changed, the relative postures of the left leg link, the waist, and the right leg link must be changed so that a result of walking is obtained as a result.
For this purpose, gait data that specifies the positions of the left and right foot tips is used. The gait data stores data specifying the positions of the left and right foot tips over time.
In the gait data creation stage, gait data is created assuming changes in the relative posture of the left leg link and the right leg link. A gait where the foot of the left leg link and the right leg link are in contact with the ground, and the foot of one leg link is raised, moved forward, and then lowered to move the free leg link one step further and land. Create data.
[0004]
When the gait data is created, the gait data is given to the robot. The robot changes the positions of the left and right toes over time according to the gait data. The robot walks by changing the relative postures of the left leg link and the right leg link over time according to gait data that specifies the positions of the left and right toes that change over time.
[0005]
If there is no deflection in the robot's mechanical system and no slip occurs between the grounding foot and the floor, the robot walks according to the gait data and is specified by the gait data creator. Should walk along the trajectory.
However, in reality, the robot's mechanical system may bend or slip between the grounding foot and the floor, so the actual robot's walking trajectory will deviate from the walking trajectory specified by the gait data. Sometimes.
If a camera is mounted on the robot and a marker whose position is known is photographed, the camera position can be calculated from the photographing result. This technique is disclosed in Patent Document 1.
Using this technology, the deviation between the actual position of the robot and the teaching position (the position specified by the gait data may be called the teaching position) is calculated, and the subsequent teaching position is corrected by the calculated deviation. It should be possible to correct the deviation between the actual position and the teaching position to be zero.
However, it doesn't really work. Usually, the camera is mounted on the head of the robot, and the camera position always moves while the robot is walking. Even if feedback control is performed on a constantly moving object, the purpose of the feedback control is not achieved, and it is difficult to walk while correcting so that the deviation between the actual position and the teaching position becomes zero. The present invention realizes a robot that walks while correcting so that the deviation between the actual position and the teaching position is zero, using a position that is stationary at least for a predetermined period, not a position that always moves. When feedback control is executed using a position that is stationary for at least a predetermined period, the stability of the feedback control is improved, and it is possible to walk while correcting so that the deviation between the actual position and the teaching position is zero. It becomes.
[0006]
[Patent Document 1]
JP 2002-48513 A
[0007]
The robot created by the present invention includes a gait data storage means for storing data for designating the position of the toes, and a left leg link based on the gait data. A joint angle group calculating means for calculating a joint angle of a plurality of joints existing in a mechanical system composed of a waist, a right leg link, and a joint angle calculated by the joint angle group calculating means. An actuator for adjusting, a device for detecting the position of the grounding foot, a device for calculating a deviation between the position where the grounding foot specified by the gait data should be and the detection position of the grounding foot detected by the position detection device, A device for correcting subsequent gait data based on the calculated deviation is provided. The robot continues walking by changing the relative postures of the left leg link, the waist, and the right leg link based on the corrected gait data.
[0008]
This robot does not use the head or camera position that constantly fluctuates, and uses the position of the grounding foot that does not move while touching the ground, when obtaining the deviation between the teaching position and the actual position. When the deviation between the teaching position and the actual position that does not move while touching the ground is calculated, the detection accuracy related to the detection position of the grounding foot improves, so the deviation from the teaching position is accurately calculated. The subsequent correction amount can be calculated without excess or deficiency.
This robot has high followability to the teaching position and high reproducibility of the walking trajectory. Further, when a plurality of robots walk at the same time, it is possible to continue walking while maintaining the relative positional relationship between the robots.
[0009]
The apparatus for detecting the position of the grounding foot includes a camera mounted on the robot head, and means for calculating the position of the grounding foot based on the on-screen position of the marker photographed by the camera and the robot posture. It is preferable.
When the grounding foot position is calculated from the camera position by taking the robot posture into consideration, the calculated grounding foot position should be a constant value during the grounding period. It is possible to calculate the position of the ground contact foot many times during the ground contact period. At this time, averaging processing or unreliable data can be excluded from the processing target, and a mathematical method for improving the reliability of the calculation result of the contact foot position can be used. The deviation between the teaching position and the actual position can be accurately calculated by the camera mounted on the head that is difficult to use for calculating the deviation because it always moves.
An apparatus for detecting a position by using radio waves or ultrasonic waves has been developed. The position of the receiver can be detected by receiving radio waves flying into the robot's activity range and analyzing the received radio waves (GPS that detects the position by receiving radio waves oscillated from artificial satellites) Similar technology is available). The position of the receiver can be detected by transmitting an ultrasonic wave toward the range of activity of the robot and analyzing the reception timing of the ultrasonic wave received by the robot. Alternatively, the position of the radar can be detected by mounting a radio wave radar or an ultrasonic radar on the robot.
If these position detection devices can be installed on the toes, the position of the grounding foot can be directly detected. However, in practice, it is difficult to install the position detection device at the tip of the foot, and it is mounted other than the leg links such as the trunk and the head. When a position detection device is mounted in addition to the leg link of the robot, it is preferable to provide means for calculating the position of the grounding foot based on the detection result of the position detection device and the robot posture.
When the toe position of the grounding foot is determined, the deviation between the teaching position and the actual position can be accurately calculated, and the subsequent correction amount can be accurately calculated.
[0010]
It is preferable to calculate the position of the grounded foot while both feet are grounded. During the period when both feet are in contact with the ground, the mechanical system of the robot is difficult to bend, and the accuracy of the position of the grounded foot calculated by adding the robot posture to the camera position is high. Alternatively, the accuracy of the position of the ground contact foot calculated by adding the robot posture to the detection result of the position detection device is high.
[0011]
In the present invention, a step of photographing a marker whose position is known by a camera mounted on the robot head, a step of calculating a camera position from the position of the marker in the screen, and a grounding operation from the calculated camera position and robot posture The step of calculating the position of the foot, the step of calculating the deviation of the grounded foot position calculated from the data specifying the stride and the position of the grounded foot calculated from the camera position, and the next step based on the calculated deviation A walking robot is controlled by performing a process of correcting specified data.
According to this control method, the reproducibility of the walking trajectory of the walking robot is enhanced, and when a plurality of robots walk at the same time, it is possible to continue walking while maintaining the relative positional relationship between the robots.
[0012]
DESCRIPTION OF THE PREFERRED EMBODIMENTS The main features of the embodiments described below will be listed first.
(Mode 1) With a camera mounted on the robot head, four markers whose positions are known are photographed. The four markers are composed of two markers on the left side and two markers on the right side, and the two markers on each side are arranged up and down. The left and right intervals and the vertical intervals between markers are known.
(Mode 2) The horizontal distance from the right marker is calculated from the distance in the imaging screen of the distance between the upper and lower two markers on the right side. The horizontal distance from the left marker is calculated from the distance in the imaging screen of the distance between the upper and lower two markers on the left side. The horizontal position of the camera is calculated from the horizontal distance from the right marker and the horizontal distance from the left marker.
(Mode 3) The operator inputs data for designating the foot position while observing the walking robot.
(Mode 4) Based on the data for designating the toe position designated by the operator, data for designating the torso position is calculated, and is composed of the data for the designated toe position and the data for the calculated torso position. Command the gait data to the robot. The robot walks following the operator's specification in near real time.
(Mode 5) Gait data composed of foot position data designated by the operator while observing a walking robot and trunk position data calculated therefrom is stored in a storage device.
(Mode 6) When the robot walks using the stored gait data, the stored gait data is corrected based on the deviation between the teaching position of the contact foot and the actual position.
[0013]
FIG. 12 shows a mechanical structure of a biped robot 2 having a mechanical system composed of a left leg link 147, a waist 101 and a right leg link 117. As shown in FIG.
The left leg link 147 includes a left upper leg 148, a left knee joint 150, a left lower leg 152, a left ankle joint 158, and a left foot tip 162. The left knee joint 150 has a variable joint angle around the pitch axis y, and the left ankle joint 158 has a variable joint angle around the pitch axis y and a joint angle around the roll axis x. In FIG. 12, the joint is represented by an actuator that changes the joint angle for the sake of clarity. For example, reference numeral 150 is commonly used for actuators that change the joint angles of the knee joint. Reference numeral 154 is an actuator that changes the joint angle of the ankle joint 158 around the pitch axis y, and reference numeral 156 is an actuator that changes the joint angle of the ankle joint 158 around the roll axis x. The left toe 162 has a force acting between the left toe 162 and the floor, in this case, a force in the roll axis x direction, a force in the pitch axis y direction, a force in the gravity line z direction, and the roll axis x. , A six-axis force sensor 160 for measuring a moment about the pitch axis y and a moment about the gravity line z is attached.
The left and right leg links 117 and 147 are symmetrical, and the right leg link 117 includes an upper right thigh 118, a right knee joint 120, a right lower thigh 122, a right ankle joint 128, and a right foot tip 132. The right knee joint 120 has a variable joint angle around the pitch axis y, and the right ankle joint 128 has a variable joint angle around the pitch axis y and a joint angle around the roll axis x. A six-axis force sensor 130 is also attached to the right foot tip 132.
The waist 101 includes a waist plate 108 and a waist pillar 104, and a waist joint 106 is provided between them. A gyroscope 102 is fixed to the lumbar column 104 to measure the tilt angle of the lumbar column 104 about the pitch axis y, the tilt angle about the roll axis x, and the rotation angle about the gravity line z-axis. The inclination angle of the lumbar column 104 around the pitch axis y and the inclination angle around the roll axis x are not affected even when the hip joint 106 rotates.
[0014]
The left leg link 147 and the waist 101 are connected by a left hip joint 146. The left hip joint 146 includes an actuator 140 that changes the joint angle around the gravity line z-axis, an actuator 142 that changes the joint angle around the pitch axis y, and an actuator 144 that changes the joint angle around the roll axis x. . The right leg link 117 and the waist 101 are connected by a right hip joint 116. The right hip joint 116 includes an actuator 110 that changes the joint angle around the gravity line z-axis, an actuator 112 that changes the joint angle around the pitch axis y, and an actuator 114 that changes the joint angle around the roll axis x. .
[0015]
When walking using the mechanical system of FIG. 12, the relative postures of the left leg link 147, the waist 101, and the right leg link 117 must be changed so that the result of walking is obtained.
For this purpose, gait data that specifies the positions and postures of the left toe, waist and right toe is used. As shown in FIG. 1, the gait data designates the positions and postures of the left toe, waist, and right foot in a global coordinate system that defines the coordinates of the space in which the robot is active. In order to specify the positions of the left foot tip, the waist, and the right foot tip, a reference point 10 is set on the left foot tip 162, a reference point 12 is set on the right foot tip 132, and a reference point 8 is set on the waist 101. Is stipulated. In order to specify the postures of the left toe, waist and right toe, a vector L perpendicular to the left toe 162 is assumed, and a vector R perpendicular to the right toe 132 is assumed and extends along the waist column 4. A vector W is assumed.
The vector L of the left toe 162 may be always vertical, or the angle may be changed following the movement of the toe. Similarly, the vector R of the right foot tip 132 may be always vertical, or the angle may be changed following the movement of the foot tip. The vector W of the waist 101 may change the forward tilt angle following the walking speed, or may maintain a constant angle.
[0016]
As shown in FIG. 6, a joystick 40 is prepared for an operator to specify the next stride and walking speed while observing a walking robot. The operator uses the joystick 40 to input data specifying the left foot tip position, data specifying the right foot tip position, and data specifying the walking speed.
[0017]
FIG. 1 exemplifies the trajectory of the left foot position and the right foot position input by the operator. The robot 2 moves the left foot along the trajectory 14 to ground, and then moves the right foot along the trajectory 16. To ground. Thereafter, similarly, the left foot is moved along the locus 18, the right foot is moved along the locus 20, the left foot is moved along the locus 22, and the right foot is moved along the locus 24.
Each stride is specified by the operator. For example, the right foot locus 24 is designated to advance by 24x in the x-axis direction and advance by 24y in the y-direction.
[0018]
A video camera 4 is mounted on the head 6 of the robot 2. The video camera 4 photographs the markers 26, 28, 30, and 32 installed outside the area where the robot 2 walks.
The four markers are composed of two markers 26 and 28 on the left side and two markers 30 and 32 on the right side, and the two markers on each side are arranged vertically. The left and right intervals (2B) between the markers and the upper and lower intervals (A) are known. Further, the positions of the four markers are known, and here, the x coordinate and y coordinate of the intermediate position between the left and right markers are (0, 0). The intermediate height between the upper and lower markers is approximately equal to the height of the camera 4.
[0019]
As shown in FIG. 3, the position of the camera 4 can be calculated when the video camera 4 captures four markers 26, 28, 30, and 32.
FIG. 4 shows an image on the shooting screen of the video camera 4. The subscript g indicates a marker image.
The video camera 4 is a CCD camera and can know the coordinates of the pixels in the shooting screen. X and Y in the expression shown in FIG. 4 indicate the coordinates of the pixels in the shooting screen. For example, X26 indicates the X coordinate in the shooting screen of the image 26g of the marker 26. The distance in the shooting screen of the image 26g of the marker 26 and the image 28g of the marker 28 is shown by the equation (1), and the distance in the shooting screen of the image 30g of the marker 30 and the image 32g of the marker 32 is shown by the equation (2). It is.
[0020]
Since the zoom rate of the video camera 4 is known and the distance between the upper and lower two markers on the left side is known, the distance in the shooting screen between the upper and lower two markers on the left calculated by the equation (1) Thus, the distance E from the midpoint between the two upper and lower markers on the left side to the video camera 4 can be calculated. Similarly, the distance F from the middle point between the upper and lower two markers on the right side to the video camera 4 can be calculated.
The equations (3) and (4) in FIG. 5 show this, and α is a coefficient calculated from the zoom rate. When the lens of the video camera is distorted and the zoom rate differs depending on the position in the shooting screen, it is preferable to prepare a lookup table that changes the coefficient α depending on the shooting position.
[0021]
In the xy coordinate system of FIG. 5, if distances E and F from a point separated by ± B in the y direction from the origin are calculated, the coordinates (Px, Py) of the position P of the camera 4 can be calculated. it can. This is shown in equations (5) and (6) in FIG.
In this way, the robot 2 shown in FIG. 1 can calculate the position (Px, Py) of the camera 4.
When the position of the camera 4 is calculated, the position of the grounding foot can be calculated by adding the posture of the robot 2 to it.
[0022]
In this embodiment, the direction in which the camera 4 is facing can also be known. As shown in FIG. 4, the average pixel position in the X direction of the images of the two markers 26 and 28 on the left side is H, and the average pixel position in the X direction of the images of the two markers 30 and 32 on the right side is K and H And the average value of K is J. Also, let the pixel position in the X direction of the center position of the camera field of view be L. Further, as shown in FIG. 5, let S be the y coordinate of the point where the center line of the camera field of view intersects the y axis. Then, equation (7) in FIG. 5 is established, and the value of S can be calculated. If the value of S can be calculated, the angle θ formed by the center line of the camera field of view and the x axis can be calculated from equation (8).
[0023]
FIG. 2 shows the position of the right foot after step 20. Reference numeral 20c denotes a position taught by the operator. On the other hand, 20d is the position of the right foot calculated by adding the posture of the robot 2 to the position of the camera 4, and is deviated from the teaching position by Δx and Δy. In this case, if the step 24x in the x direction taught for the next step 24 is lengthened by Δx and the step 24y in the y direction is shortened by Δy, the position of the right foot after step 24 is the taught position. It can be seen that it is corrected to 24c. As described above, the robot according to the present embodiment walks by correcting the subsequent stride data so that the deviation between the teaching position and the actual position becomes zero. The followability to the taught walking locus is high.
[0024]
FIG. 6 shows a control block diagram of the robot 2. The joystick 40 described above is prepared. The joystick 40 is used by an operator to designate the foottip trajectories 14, 16, 18, 20, 22, 24 illustrated in FIG. 1, and is placed outside the robot 2. The operator can also input data specifying the walking speed.
From the joystick 40, data specifying the position of the left foot tip, data specifying the position of the right foot tip, and data specifying the walking speed are input. As will be described later, the operator designates the next stride and the walking speed while observing the walking robot 2. Data for designating the position of the left foottip designated by the operator, data for designating the position of the right foottip, and data for designating the walking speed change sequentially and are inputted sequentially.
[0025]
Data specifying the position of the left foot and the data specifying the position of the right foot specified by the operator are input to the target ZMP position calculation means 42. The ZMP position refers to a point at which the moment due to the reaction force acting on the robot from the floor becomes zero, and can be calculated if the trunk position, the toe position, and the changing speed of the robot are known. Since the behavior of the robot is dynamic and influenced by inertia, the ZMP position depends on the changing speed of the trunk position and the like. If the ZMP position is within the foot of the grounding foot, the robot will not fall. If the ZMP position is outside the foot of the grounded foot, the robot falls. Therefore, it is important that the ZMP position is within the foot of the grounded foot when one foot is grounded, and moves toward the foot of the foot that will be grounded again and become the one foot grounded foot while both legs are grounded. is there. The target ZMP position calculation means 42 calculates the ZMP position from which the robot 2 should not fall if the ZMP changes so much from the data indicating the positions of the left and right toes. This is called target ZMP. The target ZMP fluctuates over time as the left and right foot tip positions fluctuate over time.
[0026]
The target ZMP calculated by the target ZMP position calculating means 42, the data indicating the positions of the left and right toes input from the joystick 40, and the data indicating the walking speed input from the joystick 40 are the trunk position calculating means 44. Is input. As described above, if the trunk position of the robot is assumed, the toe position has already been specified, and the ZMP position obtained at that time is calculated. If the ZMP position calculated in this way matches the target ZMP, the robot 2 does not fall. Therefore, the trunk position calculation means 44 calculates and calculates the trunk position that brings the target ZMP to the unknown trunk position. When the robot 2 changes its posture according to the trunk position calculated in this way and the data indicating the positions of the left and right toes, the ZMP matches the target ZMP, and the robot can walk without falling down. .
[0027]
The data indicating the left and right foot positions and the data indicating the trunk position, which change with time, are referred to as gait data. This data is stored in the gait data storage means 46.
When the operator finishes specifying the walking trajectory and the walking speed, the gait data is completed, and the completed gait data is stored in the gait data storage means 46. When the gait data is stored in the gait data storage means 46, the robot 2 can be made to walk using the gait data stored in the gait data storage means 46 thereafter. In this case, gait data correction means 48 is used.
At the stage where the operator designates gait data while observing the walking robot, the gait data correction means 48 does not operate, and the gait data stored in the gait data storage means 46 is instructed to the robot 2 as it is. .
[0028]
The robot 2 includes joint angle group calculation means 58. The joint angle group calculator 58 calculates a joint angle group that realizes the left and right toe positions and trunk positions specified by the gait data. The joint angle group calculation device 58 calculates a joint angle group by solving so-called inverse kinematics. The joint angle group calculation device 58 calculates the joint angle group in real time for the walking motion of the robot. The joint angle group calculation device 58 may be physically outside the robot 2 or may be one that transmits and specifies the calculated joint angle group to the robot 2 wirelessly or by wire.
The robot 2 includes means 60 for driving an actuator that rotates the joint, and adjusts each joint rotation angle to the joint angle calculated by the joint angle group calculation device 58.
[0029]
The robot 2 includes a video camera 4 that captures the marks 26, 28, 30, and 32, and includes a means 52 that calculates a camera position from equations (5) and (6) in FIG. Means 54 for calculating the position of the grounding foot in consideration of the posture is provided. The gait data stored in the gait data storage means 46 stores the data of the foot position relative to the position of the trunk. Further, the position of the head relative to the position of the trunk can be calculated from the posture of the trunk. Therefore, the relative position of the foot to the position of the camera 4 can be calculated from the gait data. The grounding foot position calculating means 54 includes the camera position calculated by the camera position calculating means 52 and the posture of the robot stored in the gait data storage means 46 (actually, data indicating the relative position of the foot to the camera 4). The position of the grounding foot is calculated.
The robot 2 may be equipped with a position detection device instead of the camera 4. There are no limitations on the type of position detection device, and a type that detects the position of the receiver by analyzing the received radio waves or ultrasonic waves, or a type that detects the position using radio wave radar or ultrasonic radar can be used. .
If these position detection devices can be installed at the tip of the robot 2, the position of the grounding foot can be detected directly. However, in practice, it is difficult to install the position detection device on the tip of the foot, and it is mounted on the trunk 101, the head 6, etc. other than the leg link. When a position detection device is mounted in addition to the robot leg link, the position of the grounding foot is calculated by providing means for calculating the position of the grounding foot based on the detection result of the position detection device and the robot posture. .
[0030]
The robot 2 uses the toe position of the ground foot specified by the gait data stored in the gait data storage means 46 (20c in FIG. 2) and the ground foot calculated by the ground foot position calculating means 54. Means 56 for calculating the deviation (Δx, Δy) of the position (20d in FIG. 2) is provided.
The deviations (Δx, Δy) calculated by the deviation calculating means 56 are sent to the gait data correcting means 48 and used for the subsequent correction of the gait data.
[0031]
FIG. 7 shows gait data created from the toe position designated by the operator while observing the walking robot 2, storing the created gait data in the gait data storage means 46 and instructing the robot 2. The process procedure performed when the robot 2 is walked in real time is shown. The gait data stored in the gait data storage means 46 is used for subsequent walking.
In step S1, the left toe position and the right toe position of the robot 2 when the operator starts the teaching operation are detected and stored. In this process, the mark photographing camera 4, the camera position calculation means 52, and the grounding foot tip position calculation means 54 are used, and the left foot tip position and the right foot tip position at the start of the teaching operation are detected and stored. The robot 2 is stationary with a known posture.
[0032]
In step S2, the step count t is initialized to 1. Here, the number of steps is counted for each left and right foot, and counted as the first left foot, the first right foot, the second left foot, and the second right foot.
In this embodiment, the robot 2 starts walking from the left foot. Since the operator designates the step length Lxt in the x direction (initially t = 1), the step length Lyt in the Y direction and the step speed of the first step of the left foot, the designated values are input and stored in the gait data storage means 46. (Step S4).
In step S6, a target ZMP between the left foot t steps is calculated, and the calculated target ZMP is sent to the trunk position calculation means 44. In step S <b> 8, the trunk position calculation unit 44 calculates the trunk position for the left foot t step and stores it in the gait data storage unit 46.
In step S12, the step Rxt in the x direction, the step Ryt in the Y direction, and the step speed of the right foot t step are designated, and the designated values are input and stored in the gait data storage means 46. In step S14, the target ZMP between the right foot t steps is calculated, and the calculated target ZMP is sent to the trunk position calculation means 44. In step S <b> 16, the trunk position calculation unit 44 calculates the trunk position for the right foot t step and stores it in the gait data storage unit 46.
The above process is repeated (step S20) and repeated until the operator commands the end of walking.
[0033]
FIG. 8 shows the overall processing when teaching in real time, and the gait data taught in real time in step S22 is stored in the gait data storage means 46. The details are shown in FIG. When teaching in real time, the gait data is calculated and accumulated and stored in the gait data storage means 46, and at the same time, the robot 2 is instructed. The robot 2 operates according to the commanded gait data and walks as commanded. Therefore, the operator can specify the subsequent gait data while observing the walking robot 2. It is said to teach in real time that the gait data after that is specified while observing the walking robot 2.
[0034]
FIG. 10 shows processing executed by the robot 2 to which gait data is commanded. In step S36, gait data is read, a joint angle group that realizes the read toe position and trunk position is calculated (step S38), and the actuator is controlled to match the calculated joint angle (step S40). ). This is repeated until all gait data is read out.
[0035]
FIG. 9 shows a processing procedure when the gait data taught in real time is stored in the gait data storage means 46, read out later, and the robot 2 is walked.
In step S28, the gait data is read from the gait data storage means 46. For the first step, the correction process in steps S30 to S34 is not executed, and the robot walks according to the read gait data (step S26).
When the gait data for the second step is read (step S28), the camera position is calculated using the mark photographing camera 4 and the camera position calculation means 52 (step S30). Further, in consideration of the posture of the robot, the contact foot position calculation means 54 calculates the position of the contact foot (step S32). The gait data is corrected based on the deviation between the teaching position of the contact foot and the detected position of the contact foot (step S34), and the corrected gait data is commanded to the robot (step S26). The robot 2 executes the process of FIG. 10 and walks according to the corrected gait data.
[0036]
FIG. 11 shows details of the gait data correction process. This corresponds to the details of step S34 in FIG. The process of FIG. 11 is executed while walking up to t steps and walking at the t + 1 step.
In step S44, the position of the coordinate (position on teaching) where the grounding foot should be present is calculated from the left foot coordinates Lx0, Ly0 and the right foot coordinates Rx0, Ry0 at the start of walking and the gait data up to the t-th step. . If the left foot coordinates on teaching are Lxt and Lyt and the right foot coordinates Rxt and Ryt on teaching are given, these can be calculated by the formulas described in step S44.
In step S46, the camera position is calculated using the mark photographing camera 4 and the camera position calculation means 52. Details thereof have been described with reference to FIGS. In step S48, the posture of the robot is calculated from the gait data. In step S50, the position of the grounding foot is calculated by adding the robot posture calculated in step S48 to the camera position calculated in step S46. For this calculation, the contact foot position calculation means 54 is used.
When the position of the grounding foot is calculated by the grounding foot position calculating means 54, the position of the grounding foot is calculated in a state where both feet of the robot are grounded. When both feet of the robot are in contact with the ground, the robot is less bent and the robot posture specified by the gait data agrees well with the actual posture. For this reason, in calculating the position of the grounding foot by adding the robot posture to the camera position, the grounding foot position can be accurately calculated.
During the both-foot contact period, the video camera 4 captures the marker group many times. For this reason, the position of the ground contact foot can be calculated many times. During this time, it can be assumed that the position of the grounding foot is stationary. Therefore, it is possible to perform the averaging process after removing unreliable data which is greatly different from the processing target, and it can be said that the position of the contact foot calculated in this way is accurate. If the left foot coordinates of the grounded foot calculated by averaging only reliable data are Lxu and Lyu, and the right foot coordinates are Rxu and Ryu, these accurately indicate the left foot coordinates and the right foot coordinates of the grounded foot.
In step S52, teaching left foot coordinates Lxt, Lyt, right foot coordinates Rxt, Ryt, detected left foot coordinates Lxu, Lyu, and right foot coordinates Rxu, Ryu deviations ΔLx, ΔLy, ΔRx, ΔRy are calculated.
As described above, the deviations ΔLx, ΔLy, ΔRx, ΔRy between the teaching foot position and the actual foot position when the t-th step is completed are calculated.
In step S54, the stride data of the t + 1 step is corrected using the calculated deviation. Lxt + 1, Lyt + 1, Rxt + 1, and Ryt + 1 shown in the right term of step S54 indicate the taught stride data of the t + 1 step before correction. From this, the corrected steps Lxt + 1, Lyt + 1, Rxt + 1, and Ryt + 1 are calculated by subtracting the deviations ΔLx, ΔLy, ΔRx, and ΔRy. When the t + 1 step is advanced according to the corrected stride data, as described with reference to FIG. 2, the toe position of the grounded foot when the t + 1 step is completed returns to the taught position.
[0037]
The embodiments described above are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing.
[0038]
【The invention's effect】
According to the present invention, the robot can walk according to the taught locus faithfully. When walking on the same track repeatedly, the reproducibility of the walking track is high. When a plurality of robots walk at the same time, it is possible to continue walking while maintaining the relative positional relationship between the robots.
[Brief description of the drawings]
FIG. 1 is a view showing a foottip trajectory taught to a robot and a marker used by the robot for position detection.
FIG. 2 is a diagram showing a relationship between a teaching foot tip position and an actual foot tip position and a correction amount of a stride necessary to eliminate the difference.
FIG. 3 is a diagram for explaining a process of calculating a robot position from a marker.
FIG. 4 is a diagram for explaining a process and an equation for calculating a distance from a photographed marker to a robot.
FIG. 5 is a diagram for explaining a process and an equation for calculating the position of a robot from a photographed marker.
6 is a control block diagram of the robot 2. FIG.
FIG. 7 shows a processing procedure diagram when an operator designates a foot tip position in real time and a robot walks according to designated data.
FIG. 8 is an overall processing procedure diagram when the operator designates the foot position in real time and the robot walks according to the designated data.
FIG. 9 is a processing procedure diagram when the robot walks according to gait data stored in advance.
FIG. 10 shows a processing procedure executed by a robot walking according to gait data.
FIG. 11 shows a detailed processing procedure of processing for correcting gait data.
12 shows a mechanical configuration of the robot 2. FIG.
[Explanation of symbols]
2: Robot
4: Video camera for marker photography
40: Joystick
42: Target ZMP position calculation means
44: Trunk position calculation means
46: Gait data storage means
48: Gait data correction means
52: Camera position calculation means
54: Grounding foot position calculation means
56: Deviation calculation means

Claims (5)

Gait data storage means storing data specifying the position of the toes;
A joint angle group calculating means for calculating joint angles of a plurality of joints existing in a mechanical system composed of a left leg link, a waist and a right leg link based on gait data;
An actuator for adjusting the joint angle of each joint to the joint angle calculated by the joint angle group calculating means;
A device for detecting the position of the grounding foot;
A device that calculates the deviation between the position where the grounding foot specified by the gait data should be and the detection position of the grounding foot detected by the position detection device;
A device for correcting subsequent gait data based on the calculated deviation is provided.
A robot that walks by changing the relative postures of the left leg link, waist, and right leg link based on the corrected gait data. The apparatus for detecting the position of the grounding foot includes a camera mounted on the robot head, and means for calculating the position of the grounding foot based on the on-screen position of the marker photographed by the camera and the robot posture. The robot according to claim 1. The apparatus for detecting the position of the grounding foot includes a position detection device mounted other than the leg link of the robot, and means for calculating the position of the grounding foot based on the detection result of the position detection device and the robot posture. The robot according to claim 1, wherein: 4. The robot according to claim 2, wherein the means for calculating the position of the grounding foot calculates the position of the grounding foot during a period in which both feet are in contact with the ground. The step of photographing a marker whose position is known with the camera mounted on the robot head, the step of calculating the camera position from the on-screen position of the marker, and the position of the grounding foot from the calculated camera position and robot posture A step of calculating, a step of calculating a deviation between the ground contact foot position calculated from the data specifying the stride and the ground contact foot position calculated from the camera position, and data specifying the next stride based on the calculated deviation. A method for controlling a walking robot comprising a correcting step.

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