JPH05146978A - Control device for walking type mobile robot - Google Patents

Abstract

PURPOSE:To change the gear shift ratio in response to the load state by providing a detecting means detecting the load applied to a leg section link system, a gear shift system speed-changing the output of a driving means driving the joints of a robot, and a gear shift ratio determining means determining the gear shift ratio of the gear shift system in response to the detected load. CONSTITUTION:A detecting means 36 detects the load applied to a leg section link system based on whether the leg section link system is in the support leg state or not. The gear shaft ratio of a gear shift system 44 is changed by a control unit 26 depending on whether the leg section link system is in the idle leg state or the support leg state, the output of a driving means driving the joints 16R, 15L of a robot 1 is speed-changed by the gear shaft system 44 to attain high-speed walking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for a legged mobile robot, and more specifically, a gearshift mechanism is provided at a joint of a leg link mechanism of a legged mobile robot such as a bipedal locomotive so as to respond to a load. The present invention relates to a device that controls the speed change ratio.

[0002]

2. Description of the Related Art A robot, in particular, a legged mobile robot such as an autonomous bipedal walking system has been proposed in Japanese Patent Laid-Open No. 62-97005 and the like, and the applicant of the present invention has previously mentioned Japanese Patent Laid-Open No. 3-1.
The same type is proposed in Japanese Patent Application No. 84782 (Japanese Patent Application No. 1-324218).

[0003]

By the way, the robot,
In particular, the above-mentioned bipedal legged mobile robot is provided with a base body and two leg link mechanisms, and at the time of walking, the two legs are driven while the joint is driven by a drive means such as an electric motor or a hydraulic motor. The partial link mechanism is alternately driven forward, and walking while alternately supporting its own weight. The walking state varies depending on the purpose, and for example, walking fast, walking with loaded luggage, going up and down stairs, walking on a slope, etc. are planned. In such a case, the driving speed of the driving means may be changed according to the load, but there is a limit in the capacity of the driving means to be loaded in the mobile robot. Further, in order to increase the moving speed, for example, it is possible to change the driving speed in the traveling direction between the free leg and the supporting leg, but there is a limit in dealing with the driving means itself.

Therefore, an object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a legged mobile robot capable of arbitrarily changing the output of the joint driving means of the robot. ..

Further, it is possible to provide a control device for a legged mobile robot which is capable of arbitrarily changing the output of the joint driving means of the robot and controlling the gear ratio according to the load. With the goal.

[0006]

In order to solve the above-mentioned problems, the present invention provides a legged mobile robot having a base body and a leg link mechanism connected to the base body as shown in claim 1, for example. In the control device, the detection means for detecting the load applied to the leg link mechanism, the speed change mechanism for changing the output of the drive means for driving the joint of the robot, and the speed change ratio of the speed change mechanism according to the detected load. And a gear ratio determining means for determining.

[0007]

With the provision of the speed change mechanism for changing the output of the means for driving the joint, the speed change ratio can be changed according to the walking condition.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a control system for a legged mobile robot according to the present invention will be described below by taking a bipedal legged mobile robot as an example. FIG. 1 is an overall schematic diagram thereof, and a robot 1 is provided with six joints (axes) on each of the left and right legs (for convenience of understanding, each joint (axis) is exemplified by an electric motor for driving it). ). The six joints (axes) are, in order from the top, joints (axes) 10R and 10L for rotating the legs of the hips (R on the right side, L on the left side, the same applies below), and the hip travel direction (X).
Direction) joints (axis) 12R, 12L, left and right direction (Y direction) joints (axis) 14R, 14L, knee extension direction joints (axis) 16R, 16L, ankle movement direction joint (axis) ) 18R, 18L, joints (axis) 20 in the same left-right direction
R, 20L, and feet 22R, 2L below it.
2L is attached, and the body (base) 2 is on the top.
4 is provided inside which a control unit 26 is stored.

In the above, the hip joint is the joint (axis) 10R.
(L), 12R (L), 14R (L), the ankle joint is composed of joints (axes) 18R (L), 20R (L), and the leg links are provided for the left and right feet respectively. Given 6 degrees of freedom, these 6 × during walking
By driving each of the 2 = 12 joints (axes) to an appropriate angle, a desired motion can be given to the entire foot, and the user can walk in a three-dimensional space arbitrarily. The thigh links 28R, 2 are provided between the hip joint and the knee joint.
8L, lower leg links 30R, 3 between the knee joint and the ankle joint
Connected with 0L. Further, a well-known 6-axis force sensor 36 is provided on the ankle portion, and the force components Fx, Fy, Fz in the X, Y, and Z directions transmitted to the robot via the foot portion and the moment components Mx, about the directions are transmitted. By measuring My and Mz, the presence or absence of landing of the foot and the magnitude and direction of the force applied to the supporting leg are detected. Further, known grounding switches 38 are provided at the four corners of the foot (sole) to detect the presence or absence of grounding. Further, a pair of inclination sensors 40 and 42 are installed on the upper portion of the body portion 24, and the inclination with respect to the Z axis in the XZ plane and its angular velocity, as well as the inclination with respect to the Z axis in the YZ plane and its angular velocity. To detect. Outputs of the sensors 36 and the like are sent to the control unit 26 in the body portion 24 described above.

What is characteristic of the robot 1 shown in FIG. 1 is that a speed change mechanism 44 is arranged at the knee joints 16R and 16L, and the speed change ratio is made variable in response to a command from the control unit 26. Referring to FIG. 6, the speed change mechanism 44
(Because the leg link mechanism is bilaterally symmetrical, R and L will be omitted in the following description).

FIG. 2 shows a thigh link 28 and a lower leg link 30.
It is explanatory sectional drawing which shows generally the knee joint 16 which connects with (it shows with a broken line at the lower part). The transmission mechanism 44 includes a transmission 46, a ball screw mechanism 48, and a drive motor 50.
The output of the electric motor 52 arranged above the thigh link 28 is changed by the transmission 46 to one of two gear ratios (electric motor output: transmission output = 1: 1 or 1: 0.5). The output is sent to the lower knee joint 16 via the pulley 54 and the belt 56. The transmission output sent from the knee joint 16 is the known harmonic speed reducer (trade name) 58.
One of the outputs is transmitted to the thigh link 28, and the other is transmitted to the lower leg link 30, and the thigh link 28 and the lower leg link 30 are centered around the knee joint (axis) 16 and are shown in the front and rear of the drawing in FIG. Rotate relative to the direction.
Further, the rotation amount of the electric motor 52 is detected by the encoder 60. Here, the electric motor 52 is arranged at the upper portion of the thigh link 28, that is, at a position close to the body portion (base body) 24 in order to reduce the inertial mass of the leg link mechanism below the knee joint.

FIG. 3 is an enlarged view of a main part of FIG. 2 showing the transmission 46 in detail. A drive gear 66 is attached to the output shaft 62 of the electric motor 52 via a bolt 64. The drive gear 66 includes a first gear train 66a and a second gear train 66b.
And are integrally formed. A transmission output shaft 70 is arranged in parallel with the electric motor output shaft 62, and a first driven gear 72 and a second driven gear 74 are arranged on the transmission output shaft 70.
Are independently and rotatably arranged with respect to the shaft 70. The first driven gear 72 has a third gear train 72.
a is integrally formed, the third gear train 72a has the same number of teeth as the first gear train 66a, and meshes therewith. In addition, the second driven gear 74 has a fourth gear train 7
4a is integrally formed, and the fourth gear train 74a has twice the number of teeth of the second gear train 66b and meshes with it.

As shown in FIG. 4, the inside of the transmission output shaft 70 is hollow, and a long hole 70a is formed near the left end (in the figure) of the transmission output shaft 70. Is inserted. Further, on the surfaces of the first and second driven gears 72 and 74 facing the key 76, the key 7
A key groove 72b for housing 6 is formed (only the key groove 72b of the first driven gear 72 is shown in the drawing). A spring 80 is arranged on the left end side of the key 76 inside the transmission output shaft 70 to urge the key 76 to the right, and a shift rod 82 is inserted on the right end side in the figure, and the shift rod 82 Urges the key 76 to the left when pushed. Therefore, when the shift rod 82 is pushed to the left in the figure, the electric motor output is transmitted from the transmission output shaft 70 to the drive gear 66, the first driven gear 72, and the key 7
6 is taken as no gear change (gear ratio = 1: 1), and when the speed change rod 82 moves backward to the right, the drive gear 66, the second driven gear 74, and the key 76 are used for half deceleration (gear ratio = 1: 0. 5) It is taken out and taken out. here,
The known ball screw mechanism 48 is connected to the speed change rod 82 as described above, and the ball screw mechanism 48 is used for the speed change unit 2.
The output of the drive motor 50 that receives the command of No. 6 is received to move the speed change rod 82 forward and backward, and the speed ratio is controlled to one of the above. The changed output is sent to the knee joint 16 through the pulley 54 and the belt 56 as described above.

FIG. 5 is a sectional view of the essential part of FIG. 2 showing the knee joint 16 in detail. The output of the transmission sent through the pulley 54 and the belt 56 is input to the input shaft of the harmonic speed reducer 58, and its output is obtained. On the one hand, it is transmitted via the fixing ring 58a to the thigh link 28 fixed integrally therewith, and on the other hand it is transmitted to the lower leg link 30 fixed integrally with it via the output ring 58b, and the knee joint (shaft) 16
Displace both links relative to each other. In the figure, reference numeral 84 indicates a recess formed for weight reduction.

Of the leg link mechanism of the robot 1 shown in FIG. 1, only the knee joint has been described, but the other joints also include an electric motor, a harmonic reducer, and an encoder for detecting the amount of motor rotation. It is the same in that the motor output is received by the harmonic reducer and the relative displacement of the link is performed. However, since the details thereof are described in the above-mentioned prior application of the present applicant and are not the gist of the present invention,
The description is omitted.

FIG. 6 is a block diagram showing the details of the control unit 26, which is composed of a microcomputer. The outputs of the tilt sensors 40 and 42 are A
The digital value is converted by the / D conversion circuit 100, and the output is sent to the RAM 104 via the bus 102. The encoder output for each joint motor, such as the encoder 60 disposed adjacent to the electric motor 52 for the knee joint, is input into the RAM 104 via the counter 106, and the output from the ground switch 38 or the like is waveform-shaped. It is also stored in the RAM 104 via the circuit 108. A CPU 110 is provided in the control unit, and reads a walking pattern stored in the ROM 112 to read the counter 10
The speed command value of the electric motor is calculated from the deviation from the measured value sent from No. 6, and sent to the servo amplifier 116 via the D / A conversion circuit 114. Further, as shown in the figure, the encoder output is sent to the servo amplifier via the F / V conversion circuit 118, and speed feedback control as a minor loop is realized. Further, the CPU 110 determines the gear ratio as described later, and through the second D / A conversion circuit 120, the drive motor 50, the ball screw mechanism 48, the transmission 46.
The operation of the transmission mechanism 44 is controlled. Incidentally, reference numeral 12
Reference numeral 4 denotes a joystick for commanding a gait change such as path and stride, reference numeral 126 denotes an origin switch for determining an origin (upright) posture, and reference numeral 128 denotes a limit switch for preventing overrun.

Next, the operation of the present control device will be described with reference to the flow chart of FIG.

First, in S10, each part of the apparatus is initialized, in S12, the value of the timer t is initialized to zero, and in S14, the walking pattern iθt is searched. Here, “iθt” means the target angle θ of the i-th joint at time t, and it is assumed that such target value is created off-line in advance and stored in the ROM 112 of the control unit 26 as described above. The joint number i is joint 10R =
0, joint 12R = 1 ,. ． 20L = 11. Next, in S16, the value of the counter that counts the joint number i is reset to zero.

Next, in S18, it is judged whether or not the joint number is "3" or "9", that is, the knee joint 16. In the first loop, of course, the result is negative and the program proceeds to S20, where the gear ratio is determined to be 1: 0.5 (semi-deceleration), and the program proceeds to S22 in which the transmission rod 82 is moved backward in the transmission 46. The control value of the motor 50 is determined and output. Next, in S24, the actual angle iθr of the joint is detected,
Proceeding to S26, the deviation from the target value is multiplied by a predetermined gain kp to determine the voltage control value Vcom of the electric motor of the joint, and output at S28. Next, in S30, the joint number counter is incremented, and in S32, the counter value is 1
The process is repeated until it is determined that the control value has exceeded 1, that is, the control values have been determined for all 12 joints.

When it is determined in S18 that i = 3 or 9 (knee joint) in several loops, the process proceeds to S34, where it is determined whether or not the user is on the free leg side, and when affirmative, the process proceeds to S36. Go ahead and set the gear ratio to the same speed (1: 1),
Output in S38. That is, since the load is small on the free leg side, the gear ratio is reduced to increase the driving speed and the walking speed. Next, in S40, the actual angle iθr of the knee joint is detected, and in S42, the deviation from the target value is multiplied by the gain kp ′ to obtain the control value V′com of the electric motor 52.
To decide.

When it is determined in S32 that the control values have been determined for all the joints at the time, the process proceeds to S44 in which the timer value t is incremented and S46.
In step S14, the walking pattern at the incremented time t + 1 is searched for until it is determined that the walking has ended, and the same procedure is repeated thereafter.

In the present embodiment, as described above, the speed change mechanism is connected to the electric motor for driving the knee joint of the bipedal legged mobile robot, and when the load is small, the gear ratio is reduced and the load is large. Since the gear ratio is increased when the support leg is used, the drive speed of the idle leg can be increased and high-speed walking can be realized.

FIG. 8 is a flow chart of essential parts showing a second embodiment of the present invention. The difference from the first embodiment will be mainly described. In S18, it is determined whether or not the knee joint is present. If the result is NO, the process proceeds to S20a to set the gear ratio to the same speed. Further, when it is determined in step S18 that the knee joint is reached and the process proceeds to step S34a, it is determined whether the load is equal to or more than a predetermined value. This is judged from the output of the above-mentioned 6-axis force sensor 36, for example, the robot 1
It is determined that the load is equal to or higher than a predetermined value, such as when climbing stairs. When it is determined in S34a that the load is equal to or greater than the predetermined value, the gear ratio is determined to be half deceleration in S36a. That is, in the case of this embodiment, when the load applied to the knee joint 16 is less than the predetermined value, the gear ratio is decreased to increase the walking speed,
When the load applied to the knee joint 16 is equal to or greater than a predetermined value, the gear ratio is increased to assist the bending and stretching motion in the vertical direction. In other words, it realizes high-speed walking when the load is relatively low, and when the load increases, such as when climbing stairs or carrying luggage, the walking speed is reduced instead of increasing the vertical bending force. I chose This makes it possible to walk optimally according to the load situation.

In the above-mentioned first and second embodiments, the example in which the speed change mechanism is provided in the knee joint has been shown, but the invention is not limited to this, and it can be arranged in any position such as a waist joint or an ankle joint. ..

Further, although the present invention has been described with respect to a bipedal legged mobile robot, it is needless to say that the present invention is not limited to this and one leg or three or more legs is also applicable.

[0026]

According to the first aspect of the present invention, in a controller of a legged mobile robot having a base body and a leg link mechanism connected thereto, a load applied to the leg link mechanism is detected. Since the detection means, the speed change mechanism that changes the output of the drive means that drives the joint of the robot, and the speed change ratio determination means that determines the speed change ratio of the speed change mechanism according to the detected load are configured, The gear ratio can be changed according to the situation.

According to a second aspect of the present invention, the detecting means is configured to detect the load applied to the leg link mechanism depending on whether or not the leg link mechanism is in the supporting leg state.
It is possible to realize high-speed walking by changing the gear ratio depending on whether the leg link mechanism is on the free leg or the support leg.

[Brief description of drawings]

FIG. 1 is an overall schematic view of a control device for a legged mobile robot according to the present invention.

FIG. 2 is an explanatory cross-sectional view showing in detail the entire knee joint connecting the thigh link and the lower leg link shown in FIG.

FIG. 3 is an explanatory cross-sectional view of main parts showing a speed change mechanism in the overall view of the knee joint shown in FIG.

FIG. 4 is an enlarged cross-sectional view for explaining an operation of the transmission mechanism of FIG.

FIG. 5 is an essential part explanatory cross-sectional view showing a main part of the knee joint in the overall view of the knee joint shown in FIG. 2;

6 is an explanatory block diagram showing details of a control unit shown in FIG. 1. FIG.

7 is a flow chart showing the operation of the control unit of FIG.

FIG. 8 is a flow chart of the operation of the control unit showing the second embodiment of the present invention.

[Explanation of symbols]

1-legged mobile robot (bipedal walking robot) 10R, 10L Joint (axis) for leg rotation 12R, 12L Joint in the pitch direction of the crotch (axis) 14R, 14L Joint in the roll direction of the crotch (axis) 16R , 16L Knee pitch direction joint (axis) 18R, 18L Ankle pitch direction joint (axis) 20R, 20L Ankle roll direction joint (axis) 22R, 22L Foot part 24 Body part (base body) 26 Control unit 36 6-axis force sensor 44 Transmission mechanism 46 Transmission 48 Ball screw mechanism 50 Drive motor 52 Electric motor (for knee joint)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadanobu Takahashi 1-4-1 Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. (72) Masao Nishikawa 1-4-1 Chuo, Wako-shi, Saitama Stock Company Honda Technical Research Institute

Claims (2)

[Claims] 1. A controller for a legged mobile robot comprising a base body and a leg link mechanism connected to the base body, comprising: a. Detecting means for detecting a load applied to the leg link mechanism, b. A speed change mechanism that changes the output of a drive unit that drives the joints of the robot; and c. A gear ratio determining unit that determines a gear ratio of a speed change mechanism in accordance with the detected load, and a control device for a legged mobile robot. 2. The legged movement according to claim 1, wherein the detecting means detects a load applied to the leg link mechanism depending on whether or not the leg link mechanism is in a supporting leg state. Robot controller.