JPH07205070A - Walk controller of leg type moving robot - Google Patents

Abstract

PURPOSE:To conduct countermove to outer disorder such as slide and realize stability by judging the affordable degree of stability by detecting parameters regarding the force and angle of a robot, at the same time driving a surplus joint to generate inertia force in a direction in which the affordable degree is increased, according to this judging outcome. CONSTITUTION:The waist portion of a leg type moving robot is made up of respective center joints 4-6 and respective right and left (R, L) joints 7-9, and they are connected to knee joints 10 through thign links 13. Also, the knee joints 10 are connected to ankle joints 11, 12 through lower thign links 14, and at these lower portions, flat feet 15 are provided. In addition, the respective center joints 4-6 are connected, in order, to shoulder joints 1, 2 through respective third and fourth links 16, 17 and to the knee joints 3 through upper arm links 18 and to hands 20 through lower arm links 19. In this instance, 6 axial force sensors 21 are provided at the flat feet 15, and on the basis of parameters thus detected, the affordable degree of stability is judged, and according to a judgement outcome, an inertia moment due to the inertia mass (m) of an arm is operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is preferably applied to disturbances such as slippage between a road surface and soles, side winds, and external forces while a legged mobile robot having joints capable of driving these bodies and arms is walking. The technology relates to a technique for recovering stability by changing the gait of the upper body when it becomes difficult to continue a stable walk.

[0002]

2. Description of the Related Art As a walking control device for a legged mobile robot, particularly a bipedal legged mobile robot, a weight and a joint for driving the weight are provided on the upper part of the robot, and both weights are driven when walking. A method of canceling the inertial force generated to move the robot has been proposed ("Biped Walking Robot Data Book" (Revised 2nd Edition) Ministry of Education, Science, and Research (A) "Biped Walking Robot Mechanism" And Control Research "research group (February 1986), and" Development of a biped robot that compensates for three-axis moments by body movements "
(6th Intelligent Mobile Robot Symposium, May 1992)
21st and 22nd of the month)). Further, the present applicant also proposes, as one of posture stabilization controls, a technique for landing earlier than the scheduled time to recover the posture when the legged mobile robot encounters an unexpected uneven road surface and leans forward, for example. (Japanese Patent Laid-Open No. 5-254,465).

A legged mobile robot, particularly a bipedal legged mobile robot, can walk due to the frictional force between the road surface and the sole of the foot. This frictional force causes the entire body to walk when the robot walks. Must withstand the inertial forces created by moving. In particular, the inertial force generated by swinging a heavier leg forward and backward is eventually transmitted to the road surface through the sole of the foot, which becomes propulsive force and braking force, but in a bipedal robot, it is placed apart at that time. When the left and right legs are swung in opposite directions, a spin force acts to turn the robot around the vertical axis. If the friction force is high enough, this spin force will be canceled by the friction force, and the robot can move in the designed direction, but if sufficient friction force cannot be secured, the robot will support for the spin force. It rolls around its legs, which compromises gait stability.

However, among the above-mentioned conventional techniques, the technique common to driving by providing a weight on the upper part has a constant gait, and since the upper body is swung in the same manner at all times, energy consumption is large, However, there is the inconvenience of not being able to respond to disturbances. Moreover, even with the technique proposed by the applicant, it is still not sufficient to deal with an unknown disturbance.

Therefore, an object of the present invention is to improve the stability of a free joint when the stability of walking in a legged mobile robot is about to be impaired, and to increase the stability. It is an object of the present invention to provide a walking control device for a legged mobile robot that is driven by a vehicle to restore stability.

Further, in a legged mobile robot, particularly a bipedal legged mobile robot, it is easy to spin around the vertical axis around the support leg as described above, but when spinning, the robot does not fall down. However, the traveling direction is deviated, and it deviates from the intended route. This deviation can be corrected again by providing the robot with a detection means, but the smaller the deviation, the easier the correction work. Furthermore, there are also disturbances such as cross winds.

Therefore, a second object of the present invention is to walk a legged mobile robot in which a deviation from a target value is reduced as much as possible when a disturbance such as a spin is received to facilitate the correction work. It is to provide a control device.

[0008]

In order to solve the above-mentioned problems, the present invention provides, for example, a leg which has a plurality of joints at least in its legs and which walks by driving the joints of the legs. In a mobile robot, at least one surplus joint capable of generating inertial force, detection means for detecting a parameter representative of at least one of angle information with respect to absolute space and force information with respect to environment, based on the detected parameter The robot includes a determination unit that determines a margin of stability of the robot, and a joint drive unit that drives a joint including the surplus joint. The joint drive unit is configured to detect the surplus joint according to a determination result of the determination unit. Is configured to drive in the direction of increasing the stability margin.

[0009]

[Function] With the redundant joint, the stability of the posture is judged from the inclination angle (or the rotation angle) or the inclination angular velocity (or the rotation angular velocity) in the absolute space, and when the stability is judged to be insufficient, the redundant joint is determined. Since it drives in a direction to restore stability, it is possible to continue stable walking even if an unexpected disturbance is encountered.

[0010]

EXAMPLES Specific examples will be described in detail below. still,
In the following, the gait not only means a time series change of the joint angles of the legs, but also means a time series change of all joint angles including joints of the upper body and arms. On the other hand, the term "leg gait" is used to mean only the movement of the legs and the term "body gait" is used to mean only the movement of the upper body including the arms.

FIG. 1 is a diagram showing a skeleton and a degree-of-freedom arrangement of a bipedal walking robot having a preferable mode for carrying out the present invention. As shown, the robot has a structure similar to a human body. The robot has a total of 21 degrees of freedom,
Arms have 2 degrees of freedom in the shoulders, 1 degree of freedom in the elbows, 1 in each of the three orthogonal axes in the center of the waist, 3 in the legs and 1 in the knees, 2 are placed on each foot. These degrees of freedom are configured by a combination of a joint that freely rotates around one axis, a motor that drives this joint, and an encoder that detects the rotation angle of the motor.

More specifically, the central joints 4, 5 and 6 and the left and right joints 7, 8 and 9 (corresponding to hip joints) constitute a lumbar region, and the joints 7, 8 and 9 form the thigh link 13. It is connected to the knee joint 10 via the. The knee joint 10 is connected to the ankle joints 11 and 12 via a lower leg link 14, and a foot 15 is provided on the lower portion thereof. Joints in the center of the waist 4, 5, 6
Is connected to a third link 16 which extends vertically above it and a fourth link 17 which is arranged orthogonal to the third link. The joints 1 and 2 are connected to both ends of the fourth link 17 to form a shoulder, and the joints 1 and 2 are connected to the upper arm link 1.
8 is connected to the elbow joint 3, and the elbow joint 3 is connected to the hook-shaped hand 20 via the lower arm link 19. Although not shown, the third and fourth links 1 are provided on the upper portions of the joints 4, 5 and 6 (the portions are referred to as “upper body” in this specification).
6, 17 are covered with a housing.

The symbol m indicates the sum of the inertial mass distributed over the entire arm, and when the arm is rotated about the shoulder,
A moment of inertia acts on the robot due to this mass.
Since such a configuration is well known in this field and is described in, for example, Japanese Patent Application Laid-Open No. 3-184,782 proposed by the present applicant, detailed description thereof will be omitted. For convenience of explanation, these degrees of freedom are numbered as shown in the figure.
Here, the numbers are serial numbers from the top, and R and L mean right and left. In the following description, this numeral and the symbol R or L will be commonly used in the subscript of the symbol (in principle, the number on the left side of the subscript and the R or L on the right side).

Above the foot 15 at the tip of the leg of the robot, a six-axis force sensor 21 for detecting six pieces of information on forces and moments in the X, Y, and Z axis directions is provided. As shown in FIG. 1, the arrangement of these three axes with respect to the spatial coordinates is such that the traveling direction is set to X, the lateral direction is set to Y, and the vertical direction is set to Z. Moments are also displayed on this axis, and the directions of MX, MY, and MZ are also promised as shown by the right-hand thread display method.

Further, a tilt sensor 22 for detecting the tilt angle of the robot is provided on a member connecting both legs in the waist region. Inside the sensor, a tilt angular velocity in the front-rear direction, a lateral direction, and a vertical axis rotation. The gyro 22 that detects the rotation speed (yaw rate) when the robot rotates
a, 22b, 22c are provided at positions orthogonal to each other. These three gyros output an angular velocity signal as an output signal, but if this signal is integrated over time, it can also be extracted as an angle signal. Therefore, for convenience, there are six θX, θY, θZ, θX dots, θY dots, and θZ dots. Signal is obtained
(In this specification, "dot" stands for differential value). As a specific example of the sensor, a sensor using a vibrating gyro is commercially available at a low cost, and the structure of the sensor itself does not form an important part of the present invention, and therefore further description will be omitted.

FIG. 2 is a block diagram showing an optimum control device for carrying out the present invention. The reference gait generator 30 is a part that generates a gait that can walk a known road surface in a stable manner. When the speed of the computer mounted on the robot is sufficiently high, the computer generates a gait in real time. If the computer speed is not enough to generate in real time, it can be generated offline in advance and the calculation result can be stored in the gait memory 31, and this memory can be used when actually walking. One of the desired gaits may be selected and executed. The gait of a robot is different when walking on level ground or when climbing stairs. Also, when walking on the same level ground, the walking speed and the way it bends are different, so that a practical robot can walk. At times, multiple gaits are generally required. In addition to stable walking, gait setting must also take into consideration walking that minimizes energy consumption and other design criteria, so gait design in real time depends on the ability of the computer. However, in this description, an off-line method that does not have such a problem is illustrated.

In this embodiment, at least two types of gait data are stored: a gait on the assumption that the friction of the road surface is high for walking on the same route and a gait on the assumption of a slippery road surface. . The simplest gait for slippery roads is a gait with a slightly reduced walking speed. Other than this, like a human being walking on the ice, a gait in which the hips are slightly dropped and the sole is in contact with the road surface in a wide area as long as possible is also considered, but will not be discussed here.

The knowledge base 32 of the environment stores data about the environment of the object to be walked by the robot. For example, the layout of rooms, the layout of stairs, the number of stairs, and the height of one stair. -The depth is stored in an easy-to-use form. A coefficient, which is a feedback gain KFB for swinging the arm, is entered in association with the gait together with this data, and the robot uses this coefficient as described later,
Decide how to swing your first arm.

Since the output of the tilt sensor 22 is analog in this example, it is once converted to digital and then input to the central processing circuit 35. Since the output signal of the 6-axis force sensor 21 is also analog, it is converted to digital and also input to the central processing circuit. The MM interface 36, which is an interface between a human and a robot, includes a CRT that displays the input / output status of the robot, a keyboard that transmits commands, and a gain setter that sets the gain. When setting the gain with software, you may enter it with the keyboard.

The central processing circuit 35 selects an optimum gait on the basis of all these inputs, and issues an appropriate current command to the drive motors arranged at each joint in order to execute the gait. Two motor drive circuits 37, 38 are shown in FIG.
, And the remaining motor drive circuits are shown in black box form. The number is 21 in total in this embodiment. Display drive circuit is shoulder joint 1R / L
This is for the freedom of swinging back and forth. To briefly explain one of the drive circuits, the current command value is output as a digital signal, so this is converted to an analog value by the D / A conversion circuit, then amplified by the amplifier Amp, and the motor jML / R Is rotated (j means a joint number). The rotation angle of the motor is detected by the encoder Enc, counted by the counter, and fed back to the central processing circuit 35.

FIG. 3 and FIG. 4 are flow charts for explaining the operation of the above-mentioned control device. Before entering the description of the figure, the walking control according to the present invention will be outlined.

The characteristic of this control is that it recovers from an unstable condition by utilizing inertial force and continues to walk stably again. The inertial force that can be used is a free leg, but it is desirable. When you have a joint that is not directly related to walking, such as your torso or arm, when it is unstable, you can drive this joint to reposition itself like humans do.
However, this human behavior is reflexive, and it is not clear what kind of control law is used. By using the technology already known, it is preferable that the robot behaves like a human as a result, the stability during walking is ensured, and the stability is threatened by disturbance. A technical method for restoring stability by driving the joints in a desired direction at a desired speed and in a desired order has been awaited.

Therefore, one of the features of this control is to increase the stability of the free joint in the direction of restoring the stability when the stability of walking is about to be impaired in the legged mobile robot. It is to drive at such speed to restore stability.

Referring to FIGS. 3 and 4, an example of an algorithm for driving the joints of the robot will be described below. Here, it is assumed that the robot is instructed by the operator to walk and move from point A to point B in a known environment. The robot takes out map information from the environment, searches for a route based on its current position, and divides the entire route into parts that can be walked with a single gait. For example, stairs and thresholds require different gaits, so they are divided into different areas. The illustrated algorithm exemplifies a case in which, for example, the ascending / descending of stairs is completed, a flat ground section is entered, and the section is walked with a single planned gait.

In FIG. 3, the apparatus starts at step 1, initializes the device at step 2, and then proceeds to step 3 to set gains K1, K2, K3 to be used at step 16 later.
Read. Then, in step 4, gait data for level ground walking is read from the gait memory. Here, of the two types of gait data described above, gait data that is premised on high road friction is read. The gait data is a time series table of each joint angle for both two types, and the joint angle at the time t of the joint j is represented as jαt.

Then, in step 5, what kind of environment the walking environment is, and the environment knowledge base are referred to recognize the attribute value of the environment. Geometrical environment maps and brightness are entered as the attribute values, but as the values related to the present invention, the magnitude of friction on the road surface and the presence or absence of cross winds at locations where blowers are installed, etc. Is described together with the travel route information. However, in order to avoid complications, only those relevant to the invention will be described here. In the case of FIG. 3, the feedback correction gain KFB set in association with the gait is prepared.

Subsequently, in step 6, the gain (shoulder joint angle correction gain) KFF is selected (set), and in step 7, the actual encoder value jCR / L of each joint motor is read,
In step 8, the difference ΔjCR / L between this and the command value is calculated, and in step 9, the measured values of the tilt sensor 22 and the 6-axis force sensor 21 are read.

Next, in step 10, it is judged whether the yaw rate has exceeded a predetermined first threshold value THθZ1 dot which is considerably large from the state in which one foot is floating in the air while walking. The yaw rate should not occur when the robot is moving straight ahead, and if a large yaw rate occurs, it must be expected that the stability will be impaired. However, if the gait itself is designed to drive joint 7R / L to generate yaw rate, such as when a robot turns a corner,
It is not accurate to judge the stability based only on the information of the tilt sensor 22. Therefore, specifically, in step 10, the difference (absolute value) between the yaw rate DSRD θZ dot that should be naturally generated from the gait and the detected yaw rate θZ dot is calculated,
It is judged by comparing it with the first threshold value THθZ1 dot.

When it is determined in step 10 that the yaw rate difference value is less than or equal to the first threshold value, the process proceeds to step 11 (FIG. 4). In step 11, similarly, the difference value (absolute value) between the yaw rate DSRD θZ dot and the actually occurring yaw rate θZ dot is calculated, and the difference value is compared with the first threshold value and compared with the second threshold value THθZ2 dot which is small. And determine if it is exceeded. If the difference is equal to or smaller than the second threshold value, even if a slight difference occurs between the expected value and the measured value,
We judge that it is due to mechanical play such as a motor speed reducer, and minute slip due to vibration during walking,
We do not judge that road friction is lower than expected. However, if the difference value exceeds the second threshold value in step 11, it is considered that significant slippage has occurred, the frictional force of the road surface has lost the margin, and it is determined that stable walking cannot be continued as it is.

Therefore, the routine proceeds to step 12, where the yaw rate difference value is multiplied by the feedback correction gain KFB to calculate the shoulder joint angle correction value. When it is determined in step 11 that the yaw rate difference value is less than the second threshold value, the process proceeds to step 13 and the correction value is set to 0. Next, in step 14, the difference between the previous target joint angle and the current target joint angle is multiplied by the gain K1, the encoder difference value is multiplied by the gain K2, and the correction value is multiplied by the gain K3. The value is added as the torque command value to the motor of the shoulder joint 1R / L. Here, since the left and right arms need to swing in opposite phases, the sign of the third term is different between left and right. The torque command values for the motors of the other joints are the sum of the first term and the second term without adding the third term.

Next, in step 15, the calculated torque command value is output to each joint motor through a digital-analog converter, and in step 18, it is determined whether or not the robot has finished walking in the scheduled section. . If the walking is to be continued, the process returns to step 7, and if the section is finished, the program is ended and the walking of the next section is prepared.

If it is determined in step 10 that the yaw rate difference value exceeds the first threshold value, that is, if a large slip has occurred, the process proceeds to step 16 and it is confirmed that both feet are in a supporting period. Proceeding to 17, the gait data for low friction is changed to the gait data of the two types of gait data. That is,
When the threshold value is less than the first threshold value and exceeds the second threshold value, the correction gain is changed to change the amplitude of the arm swing, and when the first threshold value is exceeded, the gait data itself is changed. I decided to do it. In the example, the gait data for low friction (specifically, the gait data for low-speed walking) is set in advance, but as previously proposed by the applicant, It can also be realized by reducing the output speed of the gait of the above, and is technically easy to realize.
Further, the fact that both legs are in the supporting period can be easily discriminated because the output FZ of the 6-axis force sensor 21 increases.

As described above, in this embodiment, even on a road surface where the frictional force cannot be predicted, when the frictional force is insufficient and stable walking becomes difficult continuously, the gait data itself is changed, or Stability is restored by changing the gain. That is, it is sufficient to prepare a small number of gaits in response to various disturbances, and try walking with a small number of gaits.If the influence of the disturbance is large, the arm or torso should cancel the influence of the disturbance. By shaking, you can respond to changes in the actual environment.

As described above, when a sufficient frictional force can be expected, it is desirable to walk with both hands and the body kept stationary without moving as much as possible in order to save energy. Therefore, it is desirable to prepare a gait in which the upper body is stationary and only both legs are moving as a reference gait. From that intention, the swing of both hands is added to this standard gait only when slippage actually occurs on a slippery road surface. Then, when the slippage is relatively large, it is determined that the stability cannot be recovered simply by shaking the arms, and the gait data for low friction with improved stability is changed. In the second gait data, the walking speed is set to be slightly slower as in the previous embodiment for safety. There is no difference from the previous embodiment in that the joint of the waist may be swung instead of swinging the arm to utilize the mass of the entire upper body.

In the above embodiment, the arm is driven by the shoulder joint in a phase opposite to the phase of the leg movement, but the hip joint (for example, joint 4R / L) is driven to drive the entire upper body. It will be obvious that it is also good. Further, even if the elbow joint, which is lighter and consumes less energy, is driven instead of the shoulder joint, the same effect can be obtained if the degree of instability is small.

In the description of the above embodiment, the yaw rate of the tilt sensor is used to determine the presence or absence of slippage, but the angle information obtained by integrating the yaw rate may be used. Alternatively, the same effect can be obtained by using the differential value of the yaw rate. When using this kind of yaw rate-derived information, there is a change rate of the angle or a change rate of the yaw rate that may be obtained from a gait, and therefore it is necessary to take the difference from the measured value.

Further, the type of sensor is not limited to the inclination sensor, and the maximum value of this amount is smaller than the maximum value of the expected value by using, for example, the lateral component FY of the outputs of the 6-axis force sensor. In this case, it may be determined that slippage has occurred. When slipping, the coefficient of static friction shifts to a coefficient of dynamic friction smaller than this, so that the grip force of the foot on the road surface decreases. Alternatively, by taking the idea of sensor fusion into consideration, it may be determined that slip occurs when either the yaw rate or the horizontal component force of the six-axis force is different from the expected value. The engineering circuit of such a judgment circuit can be easily realized by forming a judgment circuit for each piece of information and connecting the results with an OR circuit.

In the above embodiment, the case of forming a gait in advance and storing the result in the gait memory has been described. However, if the calculation speed of the computer is sufficient, the on-board computer can be used in real time. The gait may be calculated. In that case, initialization and termination may be performed at the starting point and the destination, and the algorithm may change a little, but in certain sections where the attribute value is almost constant, such as stair climbing and slope walking, walking on slippery roads on level ground. For example, the above algorithm can be applied to each section.

FIG. 5 is a flow chart showing the algorithm of the second embodiment of the present invention.

As described above, when the moment around the yaw axis has a negative frictional force on the sole of the supporting leg, the robot turns.
When the robot turns, the traveling direction is deviated even if the robot does not fall, and the robot deviates from the intended route. It is possible in principle and practically to correct this deviation again by using the inclination sensor 22 or by attaching a visual means and using the information, but the smaller the deviation, the easier the correction work. Is. In order to reduce the deviation, when the spin phenomenon is detected, it is desirable to rotate the support leg and make some correction at this time before the free leg lands. The second embodiment is based on such an intention.

Explaining below, step 1 in FIG.
After starting at 01 and following steps 102 to 109 in the same manner as in the first embodiment, the yaw rate difference value is obtained in step 110 to determine the threshold value THθ dot (second threshold value in the first embodiment).
If the yaw rate difference value exceeds this threshold value, the yaw rate difference value is multiplied by the feedback correction gain KFB (also set according to the walking speed) to calculate the correction value cαt. To do.

Next, in step 111, the motor torque command value is calculated for the lumbar joint 7R / L in the same manner as in the first embodiment, and the remaining joints are calculated in the same manner as in the first embodiment. Next, in step 112, the command value is output, and unless it is determined in step 113 that the walking has ended,
Returning to step 107, the same work is continued.

In the second embodiment, as described above, the yaw rate is monitored, and if a difference from the expected value DSRDθZ dot is detected, the hip joint 7L or 7R is driven in the direction in which the difference decreases. The orientation of the entire robot can remain substantially unchanged, even though the supporting points of the standing leg have slipped and changed direction. As a result, the path of the robot is less likely to be misaligned, and the amount of work to be corrected when the misalignment occurs is reduced. In the second embodiment, the joints 7L and 7R are driven by the same amount in the opposite directions. However, even if one of the joints, for example, the supporting leg is focused and only the joint of the supporting leg is moved, it is the same. The effect is obtained.

FIG. 6 is a flow chart showing the algorithm of the third embodiment of the present invention.

The third embodiment intends to lift the arm in the direction of falling when the robot leans in the lateral direction due to encountering a side wind or the like and keep the robot on the stable side by the inertial force at that time. .

Explaining below, step 2 in FIG.
From 01 to step 209, the process proceeds to step 210, where the square of the tilt angle θX detected by the tilt sensor 22 is obtained to determine whether or not the predetermined value Δ (significant minimum value) is exceeded. In step 211, whether the detected tilt angle θX is positive or negative is discriminated, and when it is determined that the positive value, that is, the right angle toward the traveling direction in the promise of FIG.
Correction value cRαt multiplied by FB (read in step 206)
Calculate (for the right side). At this time, cLαt (correction value for the left side) is set to 0. When the result in step 210 is negative, the program proceeds to step 212, in which both the left and right correction values are set to zero.

Next, in step 213, the elbow joint 3R /
The target angle of L is set to 0 (that is, the elbow joint is fully extended), and the process proceeds to step 214 to calculate the motor torque command value for the shoulder joint 2R / L and other joints as shown in the figure. The remaining steps are the same as in the first embodiment.

In the third embodiment, as described above, in order to increase the inertial force, the arm is extended without bending at the elbow. So if your elbow is bent for any reason, lift your arm while straightening it. In this case, the arm is lifted outward because of the influence of the crosswind, but when the user leans to the right, the right arm is lifted. The left arm is convenient because it does not interfere with the body. For this reason, a step is provided to check whether the sign of the angular velocity around the X axis is positive or negative, and the algorithm is such that either joint 2R or 2L is moved in the lifting direction according to the sign.

FIG. 7 is a flow chart showing the algorithm of the fourth embodiment of the present invention.

The fourth embodiment is a technique capable of recovering stability by using a joint other than an arm when the robot hits another object with a shoulder and receives a lateral external force, or when a side wind is encountered. Indicates. Consider the case where the robot is about to fall to the right side due to a crosswind from the left while walking in FIG. If a human encounters a scene like this, and if his hands are blocked at that time, he is leaning in the direction in which he is likely to fall (in this case, to the right) and using the inertial force at that time to restore stability. .

This is reproduced by the robot in the algorithm of the fourth embodiment. The square of the tilt angle θX detected in step 310 is compared with a predetermined value Δ, and if it is confirmed that the square is exceeded, the process proceeds to step 311, and the detected tilt angle θ is detected.
x is multiplied by the feedback correction gain KFB to calculate the correction value c6αt of the joint 6 at the center of the waist, and in step 313, a dummy angle Δα for shifting the hip position to the left to the target angle of the waist joint 9,12R / L is calculated. The target angle is corrected by the addition, and in step 314, the motor torque command value is calculated as shown for the joints including the joint 6R / L at the center of the waist. The remaining steps are the same as in the third embodiment.

In the fourth embodiment, as described above, a correction amount for driving the motor for the joint 6 at the center of the waist in the direction of correcting the collapse of the posture due to the lateral wind is added, and as a result, the output of the tilt sensor decreases (posture. To recover). However, since the balance is dynamically restored, the hip joint 9R / L and the foot joint 12R / L are driven by a small amount at the same time as the body is tilted in the direction in which the upper body is likely to fall, and a cross wind blows over the entire waist. It is necessary to move horizontally in the direction of coming. For this reason, the amount obtained by adding the minute angle Δα to the gait data is given to these four motors as a new target angle.

Therefore, in the fourth embodiment, a robot that encounters a disturbance such as a crosswind shifts its waist position to the direction in which the crosswind blows, just as when a human responds. Stability can be restored by tilting the body in the same direction as the crosswind.

FIG. 8 is a flow chart showing the algorithm of the fifth embodiment of the present invention.

The fifth embodiment is a modification of the third embodiment shown in FIG. 6, and proceeds to step 409 and then step 410.
Then, the absolute value of the moment MX detected there is compared with a predetermined value Δsquared (maximum value expected from the gait), and it is confirmed that the absolute value is exceeded. Then, the routine proceeds to step 411, where the detected moment MX is The correction value is calculated by a method similar to that of the third embodiment by determining whether the threshold value exceeds the positive threshold value (Δsquare) or the negative threshold value (−Δsquare). Incidentally, step 41
If the result is 0, the correction value is set to zero in step 413, and the elbow joint is returned to the original gait in step 414. The remaining steps are the same as in the third embodiment. Also, the effect is similar to that of the third embodiment. In this way, MX or the like can be used by the information of the 6-axis force sensor in addition to the information of the tilt sensor. This is because when leaning, all of the weight is applied to the outermost periphery of the foot of the standing leg, and MX shows the maximum value.

In the fifth embodiment, the third embodiment is modified to use the moment MX, but other embodiments can be modified in the same manner. Further, the force FY may be used in addition to the moment MX. This is because the external force due to the cross wind appears in FY in the form of shear force. The concept shown by the algorithm such as the third embodiment in FIG. 6 can be similarly applied to the disturbance in the front-rear direction as well as the disturbance in the lateral direction.
With respect to the disturbance in the front-back direction, both arms can be lifted in the same direction, and the restoring force can be increased as compared with the case of dealing with the disturbance in the lateral direction.

The effects described in the first embodiment are as follows.
It is also applicable to the second and subsequent embodiments. That is, it is sufficient to prepare a small number of gaits in response to various disturbances. Try walking with a small number of gaits, and if the influence of the disturbance is large, the arms and torso should be adjusted so as to cancel the influence of the disturbance. By shaking, it is possible to respond to actual environmental changes.

Furthermore, although the first to fifth embodiments have been described as above, they can be variously modified.
It is possible to combine them partially or wholly with one another.

[0059]

According to the first aspect of the present invention, even if the stability of the robot deteriorates due to disturbance such as insufficient frictional force on an unknown walking road surface, the stability can be easily ensured or restored. . Further, even if the traveling direction is deviated, the amount of deviation can be reduced and the subsequent correction work becomes easy.

According to the second aspect, in addition to the effect of the first aspect, it is possible to surely secure or restore the stability in a bipedal walking robot in which it is difficult to secure the stability.

According to the third aspect, in addition to the effect of the first aspect, it becomes possible to more surely secure or restore the stability in a bipedal walking robot in which it is difficult to secure the stability. .

According to the fourth aspect, in addition to the effect of the first aspect, it becomes possible to more surely secure or restore the stability in a bipedal walking robot in which it is difficult to secure the stability. .

According to the fifth aspect, in addition to the effects of the third aspect and the like, in a bipedal walking robot in which it is difficult to secure stability, it is possible to more reliably and reliably secure or restore stability. It will be possible.

According to the sixth aspect, in addition to the effects of the first aspect, for example, it is possible to extend the elbow in the lateral direction to the full extent, so that the inertial force can be utilized more effectively, Stability can be better secured or restored.

According to the seventh aspect, in addition to the effect of the first aspect, the course can be corrected before the landing of the free leg, and the correction work becomes easy.

[Brief description of drawings]

FIG. 1 is a skeleton diagram showing an overall configuration of a robot in a walking control device for a legged mobile robot according to the present invention, including a degree of freedom arrangement.

FIG. 2 is an explanatory view showing the details of the walking control device in the walking control device of the legged mobile robot according to the present invention in terms of hardware.

FIG. 3 is the first half of the flow chart showing the first embodiment of the present invention.

FIG. 4 is the latter half of the flow chart showing the first embodiment of the present invention.

FIG. 5 is a flow chart showing a second embodiment of the present invention.

FIG. 6 is a flow chart showing a third embodiment of the present invention.

FIG. 7 is a flow chart showing a fourth embodiment of the present invention.

FIG. 8 is a flow chart showing a fifth embodiment of the present invention.

[Explanation of symbols]

1,2,3,4,5,6,7,8,9,10,11,1
2 joints 12, 13, 14, 16, 17, 18, 19 link 15 foot 20 hand 21 6-axis force sensor 22 tilt sensor 30 reference gait generator 31 gait memory 32 environment knowledge base 35 central arithmetic circuit 37, 38 Motor drive circuit

Claims (7)

[Claims] 1. A legged mobile robot having a plurality of joints at least in its legs and walking by driving the joints of said legs. At least one extra joint capable of generating inertial forces, b. Detection means for detecting a parameter representing at least one of angle information with respect to absolute space and force information with respect to the environment, c. Judging means for judging the margin of stability of the robot based on the detected parameters; and d. A joint drive means for driving a joint including the surplus joint, wherein the joint drive means drives the surplus joint in a direction in which a margin of stability increases in accordance with a determination result of the determination means. A walking control device for a characteristic legged mobile robot. 2. The legged mobile robot is a bipedal walking robot having a structure similar to a human body, and a shoulder joint for driving an arm on the upper body is provided as the surplus joint, and the joint driving means is the judging means. The legged movement according to claim 1, wherein the second drive control amount is added to the drive control amount of the shoulder joint so as to increase the margin of stability in accordance with the determination result of. Robot walking control device. 3. The legged mobile robot is a bipedal walking robot having a structure similar to a human body, wherein an upper body joint capable of driving an upper body is provided as the surplus joint, and the joint drive means is the determination means. Second, the stability margin is increased in the drive control amount of the upper body joint according to the determination result of
2. The walking control device for a legged mobile robot according to claim 1, wherein the drive control amount is added. 4. The legged mobile robot is a bipedal walking robot having a structure similar to a human body, and a waist joint capable of rotationally driving an upper body is provided as the surplus joint, and the joint drive means is the determination means. The second drive control amount is added to the drive control amount of the lumbar joint so as to drive the upper body in a direction in which the robot tilts according to the determination result of 1. Control device for a legged mobile robot. 5. The joint drive means is configured to move the waist substantially horizontally in a direction opposite to the tilt direction, and the second drive means
The walking control device for a legged mobile robot according to claim 3 or 4, wherein the drive control amount is added. 6. The surplus joint is composed of at least two joints, a first joint and a second joint, which are connected in series to each other, and the joint driving means determines the first joint according to the judgment result of the judging means.
The leg system according to any one of claims 1 to 4, wherein the second joint is driven in a direction in which an inertial force viewed from the first joint increases when the joint is driven. A walking control device for mobile robots. 7. A legged mobile robot having at least an upper body and a plurality of joints in a leg, and driving the leg joint to walk. Detection means for detecting a parameter representative of the frictional force acting between the road surface and the tip of the leg, b. Judging means for judging the stability margin of the robot by comparing the detected parameter with a predetermined value; and c. The robot is provided with a gait changing unit that changes a gait according to the determination result of the determination unit, and the robot has joints for changing the direction in its legs, and slippage in the rotational direction of the robot with respect to the road surface is detected. At this time, the gait changing means drives the direction-changing joint to drive the upper body in a direction opposite to the sliding direction.