JPH05318335A - Flat leg structure of leg type walking robot - Google Patents

Abstract

PURPOSE:To increase a stability of a robot in walking in both cases that it walks on a flat walking surface and it goes up or down stairs. CONSTITUTION:Movable flat leg pieces 102A and 102B capable of moving in a direction that an effective ground-contact area to a walking area is varied are provided on a flat leg main body 100, and the movable flat leg pieces 102A and 102B are moved in that direction by an operating mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foot structure for a legged walking robot, and more particularly to a foot structure for increasing the stability of the robot during walking.

[0002]

2. Description of the Related Art Conventionally, various techniques have been proposed as to legged walking robots, and as a technique applicable to an autonomous bipedal walking type legged walking robot, Japanese Patent Laid-Open No. 62- 97005 and JP-A-62.
The technology disclosed in Japanese Patent Laid-Open No. 3-184781 has already been proposed by the applicant of the present invention as the foot structure of a bipedal walking robot. ..

[0003]

Among the legged walking robots, the bipedal walking type robot is inherently low in stability, and also secures stability during walking depending on the condition of the walking surface to be walked. Often difficult to do. That is, it is relatively easy to maintain stability when walking at a low speed on a horizontal plane, but when walking up and down stairs, walking with two legs tends to be unstable.

As one measure for increasing the stability during walking in a bipedal walking robot, it is conceivable to design the foot so that the ground contact area with respect to the walking surface is large. However, simply increasing the foot may adversely affect the stability depending on the condition of the walking surface such as the ground.

For example, even if the walking surface is a flat surface (flat ground), in general, there are often minute irregularities, and even if the irregularities are minute, a part of the ground contact surface of the foot when the robot walks. If it is locally placed on the convex portion, the ground contact surface of the foot will be inclined with respect to the walking surface and will not evenly contact the walking surface, resulting in unstable walking. On the other hand, it is the outer edge of the movable leg that is farthest from the center of the ankle joint that functions as a fulcrum with respect to the walking surface so that the robot does not fall when walking. It doesn't work. Therefore, generally, the ground plane is not formed on the entire foot, but the ground plane is usually formed only on the four corners. Specifically, there are a total of four portions at the left and right sides of the vertical plane including the center of the ankle joint along the moving direction of the robot and the front end and the rear end in the robot moving direction ( It is usual that an elastic material made of rubber or the like is adhered to the four corners) as a cushioning material, and these four corners are used as a grounding portion which is an effective grounding surface for the walking surface.

However, when the ground contact portions are formed only at the four corners of the foot as described above, the effective ground contact area of the foot with respect to the walking surface is small, which may cause instability depending on walking conditions. There is. For example, when climbing or descending stairs, which will be explained later, the entire foot is not always placed on each step of the stairs, and the rear end of the foot falls off the step or descends when climbing. Sometimes the tip of the foot will come off the step. In such a case, if the grounding parts are formed only at the four corners of the foot, the grounding part on the front end side or the rear end side of the foot will be formed. Is dislocated from the step surface, so the part that is not the ground contact part (the part where the cushioning material is not attached) contacts the edge part of the step surface, the foot is impacted, and the foot tilts with respect to the step surface. As a result, the robot may become unstable and fall.

The present invention has been made in view of the above circumstances, and it is a basic object of the invention to provide a foot structure capable of always maintaining the stability of walking even when the condition of the walking surface changes. It is what

[0008]

In order to solve the above-mentioned problems, according to the present invention, basically, the first aspect is
In the foot structure of a legged walking robot that includes a plurality of movable legs and has a foot at the tip of each movable leg, as shown in FIG. At least one movable foot piece that is movable in a direction that changes the area of the effective ground plane with respect to the walking surface is attached to each of the foot bodies, and an operating mechanism that moves the movable foot piece in the direction is described above. It is configured to be provided on the foot body.

[0009]

In the foot structure of the present invention, the area of the effective ground contact surface with respect to the walking surface can be changed by actuating the movable foot piece by the actuating mechanism. Therefore, the area of the effective grounding surface can be selected so as to maximize the stability of walking depending on the walking situation such as walking on a level ground or moving up and down stairs.

[0010]

Embodiments of the present invention will be described below by taking a bipedal robot as an example of a legged mobile robot. FIG. 1 is an explanatory skeleton diagram schematically showing the entire robot 1, in which the left and right link-shaped movable legs 2 are 6
It is equipped with individual joints (each joint is
Shown by the electric motor that drives it). These six joints are, in order from the top, joints 10R and 10L for rotating the legs of the waist (around the z axis) (R on the right side is L and L on the left side; the same applies below), and the hip roll direction (around the x axis). ) Joints 12R, 1
2L, joints 14R, 14 in the same pitch direction (around the y-axis)
L, joints 16R and 16L in the pitch direction of the knees, joints 18R and 18L in the pitch direction of the ankles, and joints 20R and 20L in the same roll direction, and below the movable foot pieces and The feet 22R and 22L having an actuating mechanism for actuating the movable foot piece are attached, and a housing (upper body) 24 is provided at the uppermost part, and inside the robot, an operation such as walking of the entire robot is performed. A control unit 26 is stored as control means for controlling the.

In the above, the hip joint is joint 10
R (L), 12R (L), 14R (L), and ankle joints are joints 18R (L), 20R (L)
It is composed of Further, the hip joint and the knee joint are connected by thigh links 32R and 32L, and the knee joint and the ankle joint are connected by lower leg links 34R and 34L, respectively. Here, the movable leg 2 is provided with six degrees of freedom for each of the left and right feet, and by driving these 6 × 2 = 12 joints (axes) by appropriate angles during walking, It is configured so that it can walk in a three-dimensional space arbitrarily by giving a desired movement to the entire foot. As described above, each of the above-mentioned joints is composed of an electric motor and is further provided with a speed reducer that boosts the output of the electric motor. For details, refer to the application previously proposed by the applicant (Japanese Patent Application No. -324218, JP-A-3-1847
No. 82) and the like, which are not the gist of the present invention per se, and therefore, further description will be omitted.

In the robot 1 shown in FIG. 1, a well-known 6-axis force sensor 36 is provided on the ankle portion, and the 6-axis force sensor 36 is transmitted to the robot via the foot x, y ,. The force components Fx, Fy, Fz in the z direction and the moment components Mx, My, Mz around the directions are measured to detect the presence or absence of landing of the foot and the magnitude and direction of the force applied to the supporting leg. Further, at the four corners of the foot 22R (L), for example, a capacitance-type ground sensor 38 (not shown in FIG. 1) is used as ground detection means for detecting the presence or absence of ground contact with the walking surface of the foot.
Is provided. When the 6-axis force sensor 36 is used as the ground contact detecting means, the ground contact sensor 38 can be omitted. Further, the housing 24 has an inclination sensor 40.
The tilt sensor 40 detects the tilt angle with respect to the z axis in the xz plane and the yz plane, that is, the tilt angular velocity with respect to the gravity direction. Further, the electric motor of each joint is provided with a rotary encoder 46 (not shown in FIG. 1) that detects the amount of rotation thereof. Further, although omitted in FIG. 1, an origin switch 42 for correcting the output of the tilt sensor 40 is provided at an appropriate position of the robot 1.
And a limit switch 44 for fail protection. These outputs are sent to the control unit 26 in the housing 24 described above.

FIG. 2 is a block diagram showing the details of the control unit 26, which is composed of a microcomputer. Here, the output of the tilt sensor 40 or the like is converted into a digital value by the A / D converter 50, and the output is transmitted to the RAM 54 via the bus 52. The output of the encoder 46 arranged adjacent to the electric motor of each joint is sent to the RAM 5 via the counter 56.
4 and the outputs of the ground sensor 38 and the like are input to the RAM 54 via the waveform shaping circuit 58.
The control unit is provided with first, second and third arithmetic units 60, 62 and 63 each composed of a CPU.
The arithmetic unit 60 reads out a preset walking pattern such as a gravity trajectory stored in the ROM 64 to calculate a target joint angle, sends the calculated target joint angle to the RAM 54, and walks on the basis of the read walking pattern. To the third arithmetic unit 63. Further, the second arithmetic unit 62 reads out the target joint angle and the detected measured value from the RAM 54, calculates the control value necessary for driving each joint, and controls the D / A converter 66 and the servo amplifier 48. It outputs to the electric motor which drives each joint via. Further, the third arithmetic unit 63 reads out a signal indicating the presence or absence of grounding from the RAM 54, and actually detects the information on the walking condition given from the first arithmetic unit 60 and other actual walking conditions as necessary. Device (not shown), for example, based on information from an image sensor for detecting stairs or the like, a control value necessary for actuation of the movable foot piece of the foot is calculated according to the situation, and D It outputs to the actuator 74 of the operation mechanism 72 for operating a movable foot piece via the / A converter 68 and the servo amplifier 70.

Next, the foot structure of the legged walking robot of the present invention will be specifically described with reference to FIG. 3 and subsequent figures.

3 to 7 show an example of the structure of the foot 22R (22L) of the robot 1 shown in FIG. 1, that is, the foot structure of the first embodiment of the present invention. 3 to 6 are movable foot pieces 102A, 10 as will be described later.
2B shows a state in which it is in a groundable position (that is, a state in which the effective grounding area is large), and FIG.
A state in which 02B is in the non-grounded position (that is, a state in which the effective grounded area is small) is shown corresponding to FIG. In each of the following drawings, the foot is symmetrical unless otherwise specified, and therefore the reference symbols L and R are omitted and simply referred to as the foot 22.

In FIGS. 3 to 7, the foot 22 is provided with a flat foot main body 100 attached to the lower end of the movable leg 2. The foot main body 100 is formed in a long plate shape in a plan view, and extends from the attachment center position of the movable leg 2 (more accurately, the vertical projection position of the ankle joint center 23) to the front end in the robot traveling direction. The length of the movable leg is longer than that of the movable leg (hence the length from the ankle to the toe) is longer than the length from the mounting center position to the rear end in the traveling direction (the length from the ankle to the heel). The mounting position for 2 is defined. And the four corners of the foot body 100, more precisely,
There are a total of four positions on both the left and right sides of the vertical plane (shown by the alternate long and short dash line 104 in FIGS. 3 and 6) along the moving direction of the robot including the ankle joint center 23, and at both front and rear ends in the moving direction of the robot. Fixed ground portions 106A, 106B, 106C, and 106D are formed on the lower surface side of the portion. These fixed ground portions 106A to 106D
Are formed by adhering cushioning materials 108 made of an elastic material such as rubber to the lower surfaces of the four corners of the foot main body 100. And these cushioning materials 10
The lower surface of 8 serves as a ground surface 109.

Further, in the foot main body 100, in the vicinity of each of the left and right edges with respect to the robot traveling direction, more accurately, at an intermediate position between the fixed grounding portion 106A and the fixed grounding portion 106B, and the fixed grounding portion 106C and the fixed grounding portion 106D. An empty space 11 which penetrates the foot main body 100 in the vertical direction and has a long rectangular shape extending in the robot traveling direction.
0A and 110B are formed, and these voids 110 are formed.
Inside A and 110B, movable foot pieces 102A and 102B having a long shape are arranged along the robot traveling direction, respectively. These movable foot pieces 102A and 102B are
In each case, a cushioning material 112 made of an elastic material such as rubber is attached to the bottom surface of the cushioning material 112, and the bottom surface of the cushioning material 112 serves as a groundable surface 114. These movable foot pieces 102A and 102B have a groundable surface 114,
As shown in FIGS. 5 and 6, fixed ground portions 106A-10
A plane including each 6D ground plane 109 (2 in FIGS. 5 to 7)
A position that is flush with the dotted line 116 (referred to as a groundable position) and a position that is separated from the face 116 as shown in FIG. (Referred to as a non-grounded position) is supported so as to be movable to and from these movable foot pieces 102A,
Each of the 102B is movable between the groundable position and the non-grounded position by an operating mechanism 72 described later.

As the operating mechanism 72, in the example of FIGS. 3 to 7, a rotary drive type actuator 74 such as a motor is used.
, Screw / screw mechanism 124, and parallel link mechanism 1
26 is used. Specifically, as shown in detail in FIG. 5, a rotary drive type actuator 74 such as a motor is mounted on the foot body 100 so as to be tiltable about a support shaft 128. Thus, the screw shaft 130 can be rotated about its axis. A female screw block 132 is screwed onto the screw shaft 130, and the female screw block 132 is provided with the foot main body 100 and the movable foot piece 102A (via link pieces 134, 136 and 138 constituting the parallel link mechanism 126). 102B). That is, one end of each of the link pieces 134 and 138 has the pin 1
40 is rotatably connected to the female screw block 132, the other end of the link piece 134 is rotatably connected to one end of the link piece 136 by a pin 142, and the intermediate portions of the link pieces 136 and 138 are respectively. Pin 14
4, 146 are rotatably supported on the foot main body 100, and the tips of the link pieces 136, 138 are rotatably attached to the movable foot piece 102A (102B) by pins 148, 150.

In the actual foot 22, the cushioning material 108 of the fixed ground portions 106A to 106D of the foot body 100 is used.
Often, the lower surface edge is chamfered in an R shape,
Further, the front end and / or the rear end of the foot main body 100 in the robot advancing direction may be curved in an R shape so that the edge portion thereof warps upward, but these points are not the gist of the present invention. , Not particularly shown in FIGS. Furthermore, when the presence or absence of the grounding state of the foot 22 is detected by using the grounding sensor 38 as shown in FIG. 2, the grounding sensor 38 is usually provided on the fixed grounding portions 106A to 106D. The ground sensor 38 is not shown in FIGS. 3 to 7 for simplification of the drawings.

In the embodiment shown in FIGS. 3 to 7 as described above, as is apparent with reference to FIGS. 5 and 7, the rotary drive type actuator 74 is driven to rotate the screw shaft 130. When it is rotated to the center, the female screw block 132 advances and retreats and the actuator 74 tilts, and accordingly, the link piece 1 of the parallel link mechanism 126.
36 and 138 are tilted, and the movable foot piece 102A (102
B) keeps horizontal and moves diagonally up and down along an arcuate trajectory centered on the pins 144, 146, whereby the groundable surface 114 of the movable foot piece 102A (102B).
Moves between a groundable position (FIGS. 5 and 6) located on the same plane as the surface 116 and a non-grounded position (FIG. 7) separated from the surface 116. Here, as shown in FIGS. 5 and 6, when the movable foot piece 102A (102B) is in the groundable position, the fixed ground portion 106A of the foot main body 100-
106D each grounding surface 109 and each movable foot piece 102A, 1
Since the groundable surface 114 of 02B is an effective grounding surface, this state corresponds to a large effective grounding area.
As shown in FIG. 6, when the movable foot piece 102A (102B) is in the non-grounded position, only the grounding surfaces 109 of the fixed grounding portions 106A to 106D are effective grounding surfaces. Equivalent to.

FIG. 8 shows a flowchart for controlling the operation of the above-described foot structure according to the walking condition. In the flowchart of FIG. 8, it is assumed that the effective ground contact area is small in the initial state, that is, the movable foot pieces 102A and 102B are in the non-ground contact position (position in FIG. 7) in the above-described embodiment. To do.

In FIG. 8, in the first step 200 after starting the control, it is judged whether or not a stair climbing walk or a descending walk is predicted. This determination may be made in the third arithmetic unit 63 shown in FIG. 2 based on the information of the walking pattern to be walked, or the presence of stairs may be detected by an image sensor (not shown). The determination may be made based on the obtained information, or both may be used in combination. If it is predicted that the stairs will move up and down in this step 200 (Y
In ES), the process proceeds to the next step 202. On the other hand, if it is not predicted (NO), as shown in step 214,
The effective ground area is not changed and the initial state is maintained, and the control loop ends. That is, the actuator 74 of the operating mechanism 72 is not driven, and the movable foot pieces 102A and 102B of the foot are not operated.

In step 202, the ground contact surface of the foot (actually, the fixed grounding portions 106A to 10A of the foot main body 100).
It is determined whether or not the 6D ground contact surface 109) is away from the walking surface. This is for driving the actuator 74 of the foot actuating mechanism 72 (and therefore each movable foot piece 102A, 10A).
This is because the operation 2B) is performed only when the foot is away from the walking surface (not in contact with the ground). That is, the movable foot piece 102A with the foot grounded,
This is because if an attempt is made to actuate 102B, a remarkably large load will be applied to the actuator 74 of the actuating mechanism 72, making it difficult to actuate the actuator 74 or causing the actuator 74 to malfunction. This step 2
In 02, the ground sensor 3 provided in advance on the foot
It may be determined by the ground detection signal from 8 or the signal from the 6-axis force sensor 36. When it is determined in step 202 that the foot is not separated from the walking surface (N
O) waits until the foot separates from the walking surface by moving to step 204, and again after step 202, step 202
Will return to. On the other hand, when it is determined in step 202 that the foot is away from the walking surface (YES), the process proceeds to next step 206.

In step 206, the actuator 74 of the actuating mechanism 72 corresponding to each movable foot piece 102A, 102B is driven to increase the effective ground contact area. That is, the actuator 74 is driven so that the movable foot pieces 102A and 102B reach the groundable position.

Here, since an actual two-legged walking type robot has two movable legs 2, step 2
02,204,206 are left and right foot (22L, 22
R) will be executed individually or sequentially. In this way, after the effective ground contact area of the foot is increased or decreased in step 206, the walking motion proceeds and the stairs are raised or lowered while maintaining the state, while the process proceeds to the next step 208. In step 208, it is determined whether or not the stairs have been raised or lowered and the initial situation has been restored. That is, it is determined whether or not the ascending / descending of the stairs has been completed during the walking after the completion of step 206. This step 208
When it is determined that the ascending and descending of the stairs has not been completed (NO), the process proceeds to step 210, the state is maintained as it is, and the step 20 is performed again after a predetermined time has elapsed.
Return to 8. On the other hand, if it is determined in step 208 that the stair climbing has been completed (YES), step 2
Move to 12.

In step 212, the effective ground contact area of the foot is returned to the initial area. That is, the actuator 74 of the operating mechanism 72 is operated to move the movable foot piece 102A,
102B is returned to the initial non-grounded position. Although not shown in FIG. 8 when executing step 212, the actuator 74 of the actuating mechanism 72 is operated only when the foot is away from the walking surface as in steps 202 and 204 already described. When the foot is grounded on the walking surface, the actuator 74 is operated after waiting for the foot to separate from the walking surface. It should be noted that this step 212 is also actually executed individually or sequentially for each of the left and right feet (22R, 22L).

As described above, when rising or walking of stairs is predicted, the effective ground contact area of the foot is enlarged and the stairs are raised or lowered in that state. On the other hand, when the stairs are not predicted to rise or stairs, When the ascending / descending is completed, that is, when walking on a flat walking surface, walk with a small effective ground contact area of the foot, so that the walking is stable even when climbing stairs or walking on a flat walking surface. It is possible to secure the sex.

Next, an example of how the effective ground contact area increases or decreases depending on whether the stairs are going up or down or walking on a flat surface will be described with reference to FIG. In FIG. 9, (A) shows the state of the foot 22 when walking on a flat walking surface 250, and (B) shows stairs 252.
The state of the foot 22 when raising is shown.

When walking on a flat walking surface 250, if the ground contact surface is large, as described above, it is easily affected by minute irregularities on the walking surface 250. For example, the ground contact surface of the foot rests on a minute convex portion and becomes unstable. Therefore, when walking on a flat walking surface 250, as shown in FIG. 9A, the effective ground contact area is small, that is, the movable foot piece 102A (102B) is in the non-grounded position and the groundable surface thereof. 114 are separated from the walking surface 250, and the fixed ground portions 106A to 106D at the four corners of the foot main body 100.
Walk with the contact surface 109 of No. 1 being an effective contact surface. By doing so, it is possible to walk stably without being affected by minute irregularities on the walking surface 250.

On the other hand, when going up or down the stairs,
As mentioned above, the effective ground contact area is small,
If the stairs are moved up and down with only the ground contact surfaces 109 at the corners being the effective ground contact surfaces, at the time of ascending, one of the ground contact surfaces of the fixed ground contact portions 106A to 106D at the four corners of the foot will be behind the robot traveling direction. Fixed grounding portions 106A and 106D on the end side
May fall off the stairs of the stairs, and when descending, of the fixed grounding portions 106A to 106D at the four corners of the foot, the fixed grounding portion 1 on the front end side in the robot advancing direction.
06B and 106C may come off the stairs. In these cases, the foot 22 inclines against the step surface of the stairs to make the robot unstable, and the part of the foot that does not have the cushioning material impacts the end of the step surface to impact the robot. May become unstable. Therefore, as shown in FIG. 9B, the effective grounding area is increased when the stairs are raised (not shown but also when the stairs are lowered). That is, the movable foot pieces 102A and 102B are moved to the groundable position. In this state, each movable foot piece 102A, 102
The groundable surface 114 of B is the fixed grounding portions 106A to 106D.
Cross-section 25 of stairs 252 flush with ground plane 109 of
4 is in contact with the fixed grounding portions 106A to 106D.
Even if any one of them disengages from the step surface 254 of the stairs 252, the foot 22 is prevented from tilting, and at the same time, the foot 22 can be prevented from receiving an impact. Therefore, the stairs can be raised or lowered stably.

Next, several other embodiments of the foot structure according to the present invention, particularly an embodiment in which a mechanical portion is modified, will be described with reference to FIG.
This will be described with reference to FIGS.

10 and 11 show movable foot pieces 102A,
102B is movably held in the vertical direction with respect to the foot main body 100, and a rotary drive type such as a motor is used as the actuator 74 of the operating mechanism 72.
302A; 300B; movable foot piece 10 by 302B
An embodiment in which 2A and 102B are moved vertically will be described. In FIGS. 10 and 11, on the left and right edges of the foot main body 100 with respect to the robot traveling direction, in the middle of the front and rear fixed ground portions 106A and 106B and in the middle of the front and rear fixed ground portions 106C and 106D, respectively. The movable foot pieces 102A and 102B are provided with the guide groove 30 along the vertical direction.
4A, 306A; 304B, 306B are guided so as to be slidable up and down. Meanwhile, the operating mechanism 72
The two rotary drive type actuators 74 such as the motors of FIG.
It is provided corresponding to B. A worm gear mechanism 310 is attached to each rotary shaft 308 of these actuators 74.
A, 312A; 310B, 312B through the cam 300
A, 302A; 300B, 302B are connected.
These cams 300A, 302A; 300B, 302B
The cam surface of each of the movable foot pieces 102A, 102A.
It is arranged so as to contact the upper surface of B. Further, springs 312 for biasing the movable foot pieces 102A, 102B upward with respect to the foot body 100 are provided near both ends of the movable foot pieces 102A, 102B.

In the embodiment shown in FIGS. 10 and 11, as shown by the solid line in FIG. 11, the movable foot piece 102A (1
02B) is in a raised position (that is, in a non-grounded position), the rotary drive type actuator 74 is driven to rotate its rotary shaft 308, and the worm gear mechanisms 310A, 312A; The cams 300A, 302A; 300B, 302B rotate, thereby pushing the movable foot pieces 102A, 102B downward against the spring 312, and the movable foot pieces 102A, 102B reach the groundable position. That is, the effective ground area is increased. 10 and 11, the movable foot pieces 102A and 102B are shown to be operated by different rotary drive type actuators 74, respectively, but both movable foot pieces 102A are operated by one common actuator. , 102B may be moved. That is, the two rotary shafts 308 may be simultaneously operated by one rotary drive type actuator.

12 and 13, the operating mechanism 72 is shown.
However, the movable foot pieces 102A and 102B are attached to the crank mechanism 40.
0 and an embodiment configured to be moved by a tilt slide mechanism 402. In FIG. 12 and FIG. 13, on the lower surfaces of the edges of the foot main body 100 on both sides with respect to the robot moving direction, the middle of the front and rear fixed grounding portions 106A and 106B and the front and rear fixed grounding portions 106C and 106D are also provided.
Movable foot pieces 102A, 102
B is provided. These movable foot pieces 102A, 1
02B is held so as to slide in the inclination direction along an inclined slide groove 404 formed on the lower surface side of the foot main body 100. A rotary drive type actuator 74 such as a motor is arranged in the center of the lower surface of the foot main body 100, and a rotary cam plate 408 is attached to a drive shaft 406 of the actuator 74. And this rotating cam plate 4
The peripheral portion of 08 and the movable foot pieces 102A and 102B are connected by crank plates 410A and 410B.

In the embodiment of FIGS. 12 and 13, when the rotary drive type actuator 74 is driven, the tilt slide groove 404 of the tilt slide mechanism 402 is moved by the crank mechanism 400 including the rotary cam plate 408 and the crank plates 410A and 410B. Movable foot strips 102A, 102
B moves in the tilt direction. In other words, the movable foot piece 10
The groundable surfaces 114 of 2A and 102B are fixed ground portions 10 respectively.
Positions that are flush with the grounding surface 109 of 6A to 106D (groundable position) and positions separated from that surface (non-grounding position)
The movable foot pieces 102A and 102B move between and.

14 and 15, the movable foot piece 102 is shown.
An embodiment in which the operating mechanism 72 is configured to rotate the A and 102B will be shown. In this case, the movable foot pieces 102A, 1
02B is provided with rotating shafts 500A and 5A so that the upper part thereof can rotate about an axis parallel to the robot moving direction.
00B and these rotations 500A, 5
00B is a rotary drive type actuator 74 such as a motor.
Worm gear mechanism 504 on the rotating shafts 502A and 502B of
A and 504B are connected.

In the embodiment of FIGS. 14 and 15, if the actuator 74 is driven, the rotational driving force is generated by the rotary shafts 502A and 502B and the worm gear mechanisms 504A and 50.
4B is transmitted to each rotary shaft 500A, 500B,
Along with the rotation of the rotation shafts 500A and 500B, the movable foot pieces 102A and 102B rotate about a horizontal axis parallel to the robot moving direction. That is, when the movable foot pieces 102A and 102B are in a state where the groundable surface 114 is horizontal downward (at the groundable position), the movable foot pieces 102A and 102B are swung up to the side and the groundable surface. 114 turns to the side (non-grounded position).

In each of the above embodiments, the foot main body 100
Although the movable foot pieces 102A and 102B are arranged at positions on both sides with respect to the robot moving direction, the movable foot pieces may be omitted in some cases, and in some cases, three or more movable foot pieces may be omitted. A movable foot piece may be provided. However, in either case, the fixed ground portion 106A of the foot main body 100 is in a state where the movable foot piece is in the groundable position.
Usually, it is configured so that the groundable surface of the movable foot piece does not extend outside the envelope connecting the outer edges of the ground surfaces 109 to 106D. Further, the foot structure according to the present invention is not limited to the bipedal walking robot, and it is needless to say that the foot structure can be applied to the foot of a walking robot having three legs or four legs or more.

[0039]

According to the invention of claim 1, in a foot structure of a legged walking robot, which is provided with a plurality of movable legs, and a foot is provided at the tip of each movable leg to allow walking. At least one movable foot piece that is movable in a direction that changes the area of the effective ground contact surface with respect to the walking surface is attached to each of the foot main bodies that are connected to each movable leg, and the movable foot piece is moved in the direction. Since the operation mechanism for moving to the foot is provided in the foot body, even if the walking condition of the robot is different, the size of the effective grounding area should be changed according to the walking condition to maximize the walking stability. Therefore, the effective ground contact area can be changed, for example, when the stairs are moved up and down and when walking on a flat walking surface, so that the walking stability can be constantly improved even under different walking situations.

According to the foot structure of the second aspect of the present invention, the foot main body is located on both sides of a vertical plane including the center of the ankle joint along the moving direction of the robot and in the moving direction of the robot. A fixed grounding portion having a grounding surface serving as an effective grounding surface on the lower surface is formed at each of the front and rear ends (that is, four corners), and the movable foot piece becomes an effective grounding surface by its movement. The movable foot piece has the same groundable surface in the same plane as the surface including the grounding surface of each of the fixed grounding portions in the middle of the fixed grounding portions before and after the robot moving direction. It is configured so that it can be moved between a groundable position located on the ground and a non-grounded position in which the groundable surface is separated from the surface including the grounding surface of each fixed grounding portion. Feet if held in ground position Only the grounding surfaces of the fixed grounding parts at the four corners of the main body are effective grounding surfaces. Therefore, when walking on a flat walking surface, there is less risk of unstable walking due to minute irregularities on the walking surface. On the other hand, when the movable foot piece is brought to the groundable position, the movable foot piece is not only at the four corners but also at the left and right edges (middle of the front and rear fixed grounding parts) with respect to the robot traveling direction. The groundable surface of is also an effective ground surface, and in that case,
When climbing up and down the stairs, there is less risk that a portion other than the effective ground plane will be placed on the end of the step surface of the stairs, and the stability of the climbing of the stairs can be increased.

Further, according to the foot structure of the invention of claim 3, the foot main body is walked when the robot walks on a substantially flat surface according to the information of the control means for controlling the walking of the robot. Since the movable foot piece is configured to be held in the non-grounded position so that only the grounded surface of each of the fixed grounding portions of FIG. 3 is an effective grounded surface, stability particularly when walking on a flat walking surface Can be increased.

Further, according to the foot structure of the invention of claim 4, according to the information of the control means for controlling the walking of the robot, when the robot walks on the stairs, the movable foot piece is in the groundable position. Since the actuating mechanism is operated so as to be located at, it is possible to enhance the stability especially when going up and down stairs.

According to a fifth aspect of the present invention, there is provided ground contact detection means for detecting whether or not the foot is in contact with the walking surface, and the operating mechanism is operated when the foot is not in contact with the ground. Since it is operated, it is possible to effectively prevent a remarkably large load from being applied to the operating mechanism or a failure of the operating mechanism due to the reaction force from the walking surface when the foot is landed.

[Brief description of drawings]

FIG. 1 is a schematic diagram generally showing an example of a control device for a legged walking robot according to the present invention.

FIG. 2 is an explanatory block diagram of a control unit shown in FIG.

FIG. 3 is a plan view showing a first embodiment of a foot structure according to the present invention.

FIG. 4 is a bottom view of the foot structure of the embodiment shown in FIG.

5 is a longitudinal sectional view of the foot structure of the embodiment shown in FIG. 3, taken along the line VV in FIG.

6 is a vertical cross-sectional view of the foot structure of the embodiment shown in FIG. 3, taken along line VI-VI in FIG.

FIG. 7 is a vertical cross-sectional view showing the example of the operating condition of the foot structure of the embodiment shown in FIG. 3 at the same position as in FIG.

FIG. 8 is a flowchart showing an example of a control flow for the operation of the foot structure of the present invention.

FIG. 9 is a schematic diagram showing a condition of a foot during walking in a legged walking robot to which the foot structure of the present invention is applied,
(A) shows a situation when walking on a flat surface, and (B) shows a situation when going up and down stairs.

FIG. 10 is a plan view showing a second embodiment of the foot structure of the present invention.

11 is a vertical cross-sectional view taken along the line XI-XI of FIG.

FIG. 12 is a bottom view showing a third embodiment of the foot structure of the present invention.

13 is a vertical sectional view taken along line XIII-XIII in FIG.

FIG. 14 is a plan view showing a fourth embodiment of the foot structure of the present invention.

15 is a vertical sectional view taken along line XV-XV in FIG.

[Explanation of symbols]

 1 Robot 2 Movable Legs 22, 22L, 22R Foot 26 Control Unit 38 as Control Means 38 Grounding Sensor 72 Actuating Mechanism 74 Actuator 100 Foot Main Body 102A, 102B Movable Foot Piece 106A, 106B, 106C, 106D Fixed Grounding Part 109 Ground plane 114 Groundable plane

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor ▲ Takahashi Hideaki 1-4-1 Chuo, Wako-shi, Saitama, Honda R & D Co., Ltd. (72) Inventor Takashi Matsumoto 1--4, Chuo, Wako, Saitama No. 1 Stock Company Honda Technical Research Institute

Claims (5)

[Claims] 1. A foot structure of a legged walking robot, comprising a plurality of movable legs, wherein a foot is provided at a tip of each movable leg so that the leg can walk freely. At least one movable foot piece that is movable in a direction that changes the area of the effective ground plane with respect to the walking surface is attached to each of the flat bodies, and an operating mechanism that moves the movable foot piece in the direction is provided. The foot structure of a legged walking robot characterized by being installed in the flat body. 2. The foot main body has an effective grounding surface on the bottom surface at both sides of a vertical plane including the center of the ankle joint along the traveling direction of the robot and at both front and rear ends in the traveling direction of the robot. A fixed grounding portion having a grounding surface that becomes a grounding surface, and the movable foot piece has a groundable surface that should become an effective grounding surface by its movement. A groundable position where the feasible surface is located in the same plane as the plane including the grounding surface of each fixed grounding portion in the middle of the fixed grounding portion before and after the robot advancing direction, and the groundable surface is the grounding surface of each fixed grounding portion. The foot structure of the legged walking robot according to claim 1, wherein the foot structure of the legged walking robot is configured so as to be movable between a non-grounded position separated from a surface including the. 3. When the robot walks on a substantially flat surface according to the information of the control means for controlling the walking of the robot, only the grounding surface of each fixed grounding portion of the foot body is effective. The foot structure of the legged walking robot according to claim 2, wherein the movable foot piece is configured to be held in a non-grounded position so as to become a ground surface. 4. When the robot walks on stairs, the operating mechanism is operated so that the movable foot piece is located at a groundable position in accordance with information from a control unit that controls the walking of the robot. The foot structure of the legged walking robot according to claim 2, which is configured to perform. 5. The grounding detection means for detecting whether or not the foot is in contact with the walking surface is provided, and the actuating mechanism is operated when the foot is not in contact with the ground. The foot structure of the legged walking robot described in.