JP3026275B2 - Foot structure of a legged walking robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, various types of legged walking robots have been proposed. Among them, a technology applicable to an autonomous bipedal legged walking robot is disclosed in No. 97005 and JP-A-62
There is a technique described in Japanese Patent Application Laid-Open No. 970006/1995, and in particular, as a foot structure of a biped walking type legged walking robot, the present applicant has already proposed a technique disclosed in Japanese Patent Application Laid-Open No. 3-184787. .

[0003]

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

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

For example, even if the walking surface is a flat surface (flat ground), there are usually many small irregularities, and even if the unevenness is minute, a part of the foot contact surface of the foot when the robot walks. However, if the foot is locally placed on the protrusion, the foot contact surface of the foot is inclined with respect to the walking surface, does not contact the walking surface uniformly, and the walking becomes unstable. On the other hand, the outer edge of the movable leg that is farthest from the center of the ankle joint functions as a fulcrum so that the robot does not fall when the robot is walking. Does not work. Therefore, in general, a ground contact surface is not formed on the entire foot, but is formed only on the four corners. Specifically, a total of four portions (i.e., a front end portion and a rear end portion in the robot traveling direction) at positions on both left and right sides of a vertical plane including the center of the ankle joint along the traveling direction of the robot ( 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 usually provided as grounding portions that become effective grounding surfaces for the walking surface.

[0006] However, when the ground contact portions are formed only at the four corners of the foot, the effective contact area of the foot with respect to the walking surface is small. There is. For example, when ascending or descending a stair, as will be described later, the entire foot is not necessarily placed on each step of the stairs. At times, the tip of the foot often comes off the step surface. In such a case, if the grounding portion is formed only at the four corners of the foot, the grounding portion on the front end side or the rear end side of the foot can be obtained. Is disengaged from the step surface, so that the part that is not the ground contact part (the part where the cushioning material is not stuck) touches the edge of the step surface and the foot is impacted, and the foot is tilted 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 a basic object of the present invention is to provide a foot structure capable of always maintaining walking stability even when the state of a walking surface changes. It is assumed that.

[0008]

Means for Solving the Problems In order to solve the above-mentioned problems, in the present invention, basically, the first aspect of the present invention is described.
As shown in the figure, in a foot structure of a legged walking robot having a plurality of movable legs and providing a foot at the tip of each movable leg to be able to walk freely, it is connected to each movable leg. At least one movable foot piece that can move 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, and an operation mechanism that moves the movable foot piece in the direction is provided. 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 operating the movable foot piece by the operating mechanism. Therefore, the area of the effective ground contact surface can be selected so as to maximize the stability of walking according to the walking situation such as when walking on flat ground or when going up and down stairs.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below, taking a bipedal walking robot as an example of a legged mobile robot. FIG. 1 is an explanatory skeleton diagram schematically showing the entirety of the robot 1. The left and right link-shaped movable legs 2 are 6
(Each joint for convenience of understanding,
Shown by the electric motor driving it). These six joints are, in order from the top, joints 10R and 10L for rotation of the hip leg (around the z-axis) (R on the right, L on the left; the same applies hereinafter), and the roll direction of the waist (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 knee, joints 18R and 18L in the pitch direction of the ankle, and joints 20R and 20L in the same roll direction. Foot 22R, 22L provided with an operation mechanism for operating the movable foot piece is attached, and a housing (upper body) 24 is provided at the top, and inside the operation, such as walking of the entire robot, is performed. A control unit 26 is stored as control means for controlling the control.

In the above, the hip joint is the joint 10
R (L), 12R (L) and 14R (L), and the ankle joints are joints 18R (L) and 20R (L)
Therefore, it is constituted. 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 crus links 34R and 34L. Here, the movable leg 2 is given six degrees of freedom for each of the left and right feet, and by driving these 6 × 2 = 12 joints (axes) by an appropriate angle during walking, It is configured such that a desired movement can be given to the entire foot and the user can walk in a three-dimensional space arbitrarily. As described above, each of the above-mentioned joints is composed of an electric motor, and further includes a speed reducer for boosting the output of the joint. For details, refer to the application proposed by the present applicant (Japanese Patent Application No. -324218, JP-A-3-1847
No. 82) and the like are not themselves the subject of the present invention, and therefore, further description will be omitted.

In the robot 1 shown in FIG. 1, a known six-axis force sensor 36 is provided at the ankle, and the six-axis force sensor 36 transmits x, y, and The force components Fx, Fy, Fz in the z direction and the moment components Mx, My, Mz around the directions are measured, and the presence or absence of landing on the foot and the magnitude and direction of the force applied to the support leg are detected. Also, at the four corners of the foot 22R (L), for example, a capacitance type ground sensor 38 (omitted in FIG. 1) as ground detection means for detecting the presence or absence of the ground on the walking surface of the foot.
Is provided. When the six-axis force sensor 36 is used as the grounding detecting means, the grounding sensor 38 can be omitted. Further, the housing 24 includes an inclination sensor 40.
The tilt sensor 40 detects a tilt angle with respect to the z-axis in the xz plane and the yz plane, that is, a tilt angular velocity with respect to the direction of gravity. The electric motor of each joint is provided with a rotary encoder 46 (omitted in FIG. 1) for detecting the amount of rotation. Although not shown 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 failure countermeasures. These outputs are sent to the control unit 26 in the housing 24 described above.

FIG. 2 is a block diagram showing details of the control unit 26. The control unit 26 is constituted by a microcomputer. Here, the output of the inclination sensor 40 and 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 disposed adjacent to the electric motor of each joint is transmitted to the RAM 5 via the counter 56.
4 and the output of the ground sensor 38 and the like are input to the RAM 54 via the waveform shaping circuit 58.
First, second and third arithmetic units 60, 62 and 63 each comprising a CPU are provided in the control unit.
The arithmetic unit 60 reads a predetermined walking pattern such as a gravitational trajectory stored in the ROM 64, calculates a target joint angle, sends the calculated target joint angle to the RAM 54, and determines a walking state based on the read walking pattern. Is given to the third arithmetic unit 63. Further, the second arithmetic unit 62 reads out the target joint angle and the detected actual value from the RAM 54, calculates a control value necessary for driving each joint, and controls the D / A converter 66 and the servo amplifier 48. Output to the electric motor that drives each joint. Further, the third arithmetic unit 63 reads the signal indicating the presence / absence of grounding from the RAM 54, and actually detects the information on the walking state provided from the first arithmetic unit 60 and other walking states as necessary. Control device necessary for the operation of the movable foot piece of the foot is calculated according to the situation based on information from an apparatus (not shown) for example, for example, an image sensor for detecting stairs, etc. The signal is output via an / A converter 68 and a servo amplifier 70 to an actuator 74 of an operating mechanism 72 for operating the movable foot piece.

Next, the foot structure of the legged walking robot of the present invention will be described in detail with reference to FIG.

FIGS. 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. FIGS. 3 to 6 show movable foot pieces 102A and 102A,
FIG. 7 shows a state where 2B is in a position where the ground can be touched (that is, a state where the effective ground area is large).
FIG. 5 shows a state where 02B is in the non-ground position (ie, a state where the effective ground area is small). In addition, in each of the following drawings, the foot is symmetrical unless otherwise specified, so the symbols of L and R are omitted, and the foot is simply represented as foot 22.

3 to 7, the foot 22 includes a flat foot main body 100 attached to the lower end of the movable leg 2. As shown in FIG. The foot main body 100 is formed in a long plate shape when viewed two-dimensionally, and a front end in the robot traveling direction from a mounting center position of the movable leg 2 (more precisely, a vertical projection position of the ankle joint center 23). So that the length of the movable leg is longer than the length from the mounting center position to the rear end in the traveling direction (therefore, the length from the malleolus to the heel). 2 is determined. And, more precisely, the four corners of the foot body 100,
A total of four positions on both left and right sides of a vertical plane (shown by a dashed line 104 in FIGS. 3 and 6) along the traveling direction of the robot including the center 23 of the ankle joint, and both front and rear ends in the traveling direction of the robot The fixed ground portions 106A, 106B, 106C, and 106D are formed on the lower surface side of the portion. These fixed ground parts 106A to 106D
Are formed by attaching a cushioning material 108 made of an elastic material such as rubber to the lower surface of the four corners of the foot main body 100. And these cushioning materials 10
The lower surface of each of the reference numerals 8 is a ground plane 109.

Further, near the left and right edges of the foot main body 100 with respect to the traveling direction of the robot, more precisely, an intermediate position between the fixed grounding portions 106A and 106B and the fixed grounding portions 106C and 106D. In the middle position between the space 11 and the space 11, each of which has a long rectangular shape, which penetrates the foot body 100 up and down and is long along the robot traveling direction.
0A and 110B are formed.
In A and 110B, movable foot pieces 102A and 102B each having a long shape along the traveling direction of the robot are provided. These movable foot pieces 102A, 102B
In any case, a cushioning material 112 made of a material having elasticity such as rubber is adhered to the lower surface, and the lower surface of the cushioning material 112 is a groundable surface 114. And these movable foot pieces 102A and 102B have their
As shown in FIG. 5 and FIG.
The plane including each ground plane 109 of 6D (2 in FIG. 5 to FIG. 7).
A position that is flush with the surface 116 (shown by a dashed-dotted line 116) (this position is referred to as a groundable position) and a position that is separated from the surface 116 as shown in FIG. (Which is referred to as a non-ground position).
102B is moved between the groundable position and the non-grounded position by an operation mechanism 72 described later.

In the example shown in FIGS. 3 to 7, the operating mechanism 72 is a rotary drive type actuator 74 such as a motor.
, Screw / screw mechanism 124, and parallel link mechanism 1
26. More specifically, as shown in detail in FIG. 5, a rotary drive type actuator 74 such as a motor is mounted on the foot main body 100 so as to be tiltable about a support shaft 128. Thereby, the screw shaft 130 is rotated about the axis. A female screw block 132 is screwed into the screw shaft 130, and the female screw block 132 is connected to 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 the link pieces 134 and 138 is
40, 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, 138 are respectively connected. Pin 14
4, 146, the tip of the link piece 136, 138 is rotatably attached to the movable foot piece 102A (102B) by the pin 148, 150.

In the actual foot 22, the cushioning material 108 of the fixed grounding portions 106A to 106D of the foot main body 100 is used.
In many cases, the lower edge of the is chamfered in an R shape,
Also, the front end and / or the rear end of the foot body 100 in the robot traveling direction may be curved in an R-shape so that the edge of the foot body 100 warps upward. However, these points are not the gist of the present invention. , Especially not shown in FIGS. In addition, when the presence or absence of the grounding state of the foot 22 is detected using the grounding sensor 38 as shown in FIG. 2, the grounding sensor 38 is usually provided in the fixed grounding portions 106A to 106D. 3 to 7, the ground sensor 38 is not shown for simplification of the drawing.

In the embodiment shown in FIGS. 3 to 7 as described above, as apparent from FIGS. 5 and 7, the screw shaft 130 is driven by driving the rotary drive type actuator 74. When rotated about the center, the female screw block 132 advances and retreats, and the actuator 74 tilts.
36, 138 are tilted, and the movable foot piece 102A (102
B) moves diagonally up and down along an arc trajectory centered on the pins 144 and 146 while maintaining the horizontal position, whereby the groundable surface 114 of the movable foot piece 102A (102B) is moved.
Move 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 102 </ b> A (102 </ b> B) is in the groundable position, the fixed ground parts 106 </ b> A to 106 </ b> A of the foot main body 100.
106D and each movable foot piece 102A, 1
Since the groundable surface 114B of 02B is an effective grounding surface, this state corresponds to a state where the effective grounding area is large.
When the movable foot piece 102A (102B) is in the non-ground position, only the ground surfaces 109 of the fixed ground portions 106A to 106D become effective ground surfaces as shown in FIG. Equivalent to.

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

Referring to FIG. 8, in the first step 200 after starting the control, it is determined whether or not the ascending or descending walking of the stairs is predicted. This determination may be made in the third arithmetic unit 63 shown in FIG. 2 based on information on a walking pattern to be walked from now on, or by detecting the presence of stairs by an image sensor (not shown). The determination may be made based on the obtained information, or the both may be used in combination. In this step 200, when the ascending and descending of the stairs is predicted (Y
In ES), the process proceeds to the next step 202. On the other hand, when it is not predicted (NO), as shown in step 214,
The control loop ends without changing the effective contact area, while maintaining the initial state. 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 foot contact surface (actually, the fixed contact portions 106A to 106A to
It is determined whether the 6D contact surface 109) is apart from the walking surface. This is achieved by driving the actuator 74 of the foot operating mechanism 72 (therefore, each movable foot piece 102A, 10A).
2B) is performed only in a state in which the foot is away from the walking surface (a state in which the foot is not grounded). That is, the movable foot piece 102A,
This is because, when trying to operate 102B, a remarkably large load is applied to the actuator 74 of the operating mechanism 72, and it becomes difficult to operate the actuator 74 or the actuator 74 breaks down. This step 2
02, the grounding sensor 3 previously provided on the foot
The determination may be made based on the ground detection signal from the sensor 8 or the signal from the six-axis force sensor 36. When it is determined in step 202 that the foot is not separated from the walking surface (N
O), the process proceeds to step 204 and waits until the foot separates from the walking surface;
Will return to. On the other hand, if it is determined in step 202 that the foot is away from the walking surface (YES), the process proceeds to the next step 206.

In step 206, the actuator 74 of the operating mechanism 72 corresponding to each of the movable foot pieces 102A and 102B is driven to increase the effective contact area. That is, the actuator 74 is driven so that each of the movable foot pieces 102A and 102B reaches the position where the ground can be contacted.

Here, since the actual bipedal walking type robot has the two movable legs 2,
02, 204, and 206 are left and right feet (22L, 22
R) are executed individually or sequentially. After the effective ground contact area of the foot is increased or decreased in step 206 in this manner, the walking operation proceeds while maintaining the state, and the stairs are raised or lowered. During that time, the process proceeds to the next step 208. In step 208, it is determined whether or not the ascending or descending of the stairs has been completed and has returned to the initial state. That is, it is determined whether or not the ascending and descending of the stairs has been completed during the walking after the end of step 206. This step 208
If it is determined that the ascending and descending of the stairs has not been completed yet (NO), the process proceeds to step 210, where the state is maintained, and after a predetermined time elapses, step 20 is performed again.
Return to 8. On the other hand, if it is determined in step 208 that climbing of the stairs has been completed (YES), step 2
It moves to 12.

In step 212, the effective contact area of the foot is returned to the initial area. That is, by operating the actuator 74 of the operating mechanism 72, the movable foot piece 102A,
102B is returned to the initial non-ground position. Although not shown in FIG. 8, when executing step 212, the actuator 74 of the operating 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 in contact with the walking surface, the actuator 74 is operated after the foot is separated from the walking surface. In addition, this step 212 is actually executed individually or sequentially for each of the left and right foot (22R, 22L).

As described above, when ascending or walking up the stairs is predicted, the effective contact area of the foot is enlarged and the stairs are raised and lowered in that state. When the ascent / descent is completed, that is, when walking on a flat walking surface, the user walks with a small effective contact area of the foot, thereby stabilizing the walking in both situations of climbing up and down stairs and walking on a flat walking surface. Nature can be secured.

Next, a description will be given, with reference to FIG. 9, of how the effective contact area is increased or decreased in accordance with the case of ascending and descending stairs and the case of walking on a flat surface. 9A shows a state of the foot 22 when walking on a flat walking surface 250, and FIG.
Shows the state of the foot 22 when ascending.

When walking on the flat walking surface 250, as described above, if the contact surface is large, the walking surface 250 is easily affected by minute irregularities. For example, the foot contact surface is placed on the minute projections, and becomes unstable. Therefore, when walking on the 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-ground position and the ground contact surface 114 are away from the walking surface 250, and the fixed grounding portions 106A to 106D at the four corners of the foot body 100
Walk in a state in which the contact surface 109 is an effective contact surface. By doing so, it is possible to walk stably without being affected by minute unevenness of the walking surface 250.

On the other hand, when going up or down the stairs,
As described above, the effective contact area is small,
If the stairs are moved up and down while only the ground contact surface 109 at the corner is the effective ground contact surface, at the time of ascent, the ground contact surface of the fixed ground contact portions 106A to 106D at the four corner portions of the foot is located behind the robot in the traveling direction. Fixed grounding sections 106A, 106D on the end side
May fall off the step surface of the stairs, and at the time of descending, of the grounding surfaces 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 traveling direction.
06B and 106C may come off the step surface of the stairs. In these cases, the foot 22 is inclined to contact the step surface of the stairs to make the robot unstable, and the portion 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. 9 (B), when the stairs rise (not shown, the same applies when descending), the effective contact area is increased. That is, the movable foot pieces 102A and 102B are moved to a position where they can touch the ground. In this state, each movable foot piece 102A, 102
B, the groundable surface 114 is fixed grounding portions 106A to 106D.
Cross section 25 of the stairs 252
4, the fixed grounding portions 106A to 106D
Even if either of them falls off the step surface 254 of the stairs 252, the foot 22 can be 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 of 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.

FIGS. 10 and 11 show movable foot pieces 102A,
102B is held movably in the vertical direction with respect to the foot body 100, and a cam 300A,
302A; 300B; 302B;
An embodiment in which 2A and 102B are vertically moved is shown. 10 and 11, the left and right edges of the foot main body 100 with respect to the traveling direction of the robot are positioned between the front and rear fixed grounding portions 106A and 106B and between the front and rear fixed grounding portions 106C and 106D, respectively. The movable foot pieces 102A, 102B are vertically aligned with the guide grooves 30.
4A, 306A; provided so as to be slidable up and down guided by 304B, 306B. On the other hand, the operating mechanism 72
The two movable actuators 74 such as the motors are mounted on the foot main body 100 by the movable foot pieces 102A, 102A.
B is provided. A worm gear mechanism 310 is attached to each rotation shaft 308 of these actuators 74.
A, 312A; cam 300 via 310B, 312B
A, 302A; 300B, 302B are connected.
These cams 300A, 302A; 300B, 302B
Each has a cam surface whose movable foot piece 102A, 102A
B is arranged to be in contact with the upper surface of B. Further, springs 312 for urging the movable foot pieces 102A, 102B upward with respect to the foot main body 100 are provided near both ends of the movable foot pieces 102A, 102B, respectively.

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 the raised position (that is, in the non-grounded position), when the rotary drive type actuator 74 is driven to rotate its rotary shaft 308, the worm gear mechanism 310A, 312A; 310B, 312B. As a result, the cams 300A, 302A; 300B, 302B rotate, whereby the movable foot pieces 102A, 102B are pushed down against the spring 312, and the movable foot pieces 102A, 102B reach the groundable position. That is, the effective contact area is increased. 10 and 11, each movable foot piece 102A, 102B is shown to be operated by a different rotary drive type actuator 74. However, both movable foot pieces 102A and 102B are operated by one common actuator. , 102B may be moved. That is, two rotation shafts 308 may be simultaneously operated by one rotation drive type actuator.

FIGS. 12 and 13 show the operation mechanism 72.
Move the movable foot pieces 102A and 102B to the crank mechanism 40.
An embodiment configured to be moved by a zero and tilt slide mechanism 402 is shown. 12 and 13, on the lower surface of both sides of the foot main body 100 with respect to the traveling direction of the robot, the middle of the front and rear fixed grounding portions 106A and 106B and the same front and rear fixed grounding portions 106C and 106D.
The movable foot pieces 102A, 102
B is provided. These movable foot pieces 102A, 1
02B is held so as to slide in an inclined 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 provided at the center of the lower surface of the foot body 100, and a rotary cam plate 408 is attached to a drive shaft 406 of the actuator 74. And this rotary cam plate 4
08 and the movable foot pieces 102A, 102B are connected by crank plates 410A, 410B.

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

FIGS. 14 and 15 show the movable foot piece 102.
An embodiment in which the operating mechanism 72 is configured to rotate A and 102B is shown. In this case, the movable foot pieces 102A, 1
02B is provided with rotating shafts 500A, 500A, 5B so as to be able to rotate around an axis parallel to the robot traveling direction at the upper part thereof.
00B, and these rotations 500A, 5A
00B is a rotary drive type actuator 74 such as a motor.
Worm gear mechanism 504
A, 504B.

In the embodiment of FIGS. 14 and 15, when the actuator 74 is driven, the rotational driving force is applied to the rotating shafts 502A and 502B and the worm gear mechanisms 504A and 504.
4B to each of the rotating shafts 500A and 500B,
The movable foot pieces 102A, 102B rotate about a horizontal axis parallel to the robot traveling direction along with the rotation of the rotation axes 500A, 500B about the axes. That is, each of the movable foot pieces 102A and 102B has a state in which its groundable surface 114 is horizontal downward (groundable position), and each of the movable foot pieces 102A and 102B is swung up to the side to ground. It will rotate between the state where 114 is facing sideways (non-ground position).

In each of the above embodiments, the foot body 100
Although the movable foot pieces 102A and 102B are disposed at positions on both sides with respect to the robot traveling direction in, one of the movable foot pieces can be omitted in some cases. May be provided. However, in any case, the fixed foot portion 106A of the foot main body 100 is in a state where the movable foot piece is at the groundable position.
In general, the groundable surface of the movable foot piece does not protrude outside the envelope connecting the outer edges of the grounding surfaces 109 to 106D. Further, the foot structure of the present invention is not limited to a biped walking robot, and can be applied to a foot of a three or four or more walking robot.

[0039]

According to the first aspect of the present invention, there is provided a foot structure of a legged walking robot having a plurality of movable legs, and providing a foot at the tip of each movable leg to enable free 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 coupled to each movable leg portion, and the movable foot piece is moved in the direction described above. Since the foot is provided with an operation mechanism for moving the robot, even when the walking situation of the robot is different, according to the situation, the size of the effective contact area is changed so as to maximize walking stability. For example, the effective contact area can be changed between when the stairs are moved up and down and when walking on a flat walking surface, so that the stability of walking can always be improved even under different walking conditions.

According to the foot structure of the second aspect of the present invention, the foot main body is located at both sides of a vertical plane including the center of the ankle joint and along the traveling direction of the robot, and furthermore, in the traveling 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 (i.e., four corners), and the movable foot piece becomes an effective grounding surface due to the movement thereof. The movable foot piece has a groundable surface that is in the same plane as the plane including the grounding surfaces of the fixed grounding portions in the middle of the fixed grounding portions before and after the robot traveling direction. And the groundable surface can be moved between a non-grounding position in which the groundable surface is separated from the surface including the grounding surface of each fixed grounding portion. If you are holding it in the ground position Only the grounding surface of the fixed grounding portion at the four corners of the main body becomes the effective grounding surface, and in that case, when walking on a flat walking surface, there is little possibility that walking becomes unstable due to minute unevenness of the walking surface. On the other hand, when the movable foot piece is brought to the groundable position, the movable foot piece is located not only at the four corners but also at the left and right edges (middle of the front and rear fixed grounding portions) in the traveling direction of the robot. Groundable surface is also an effective ground surface, so in that case,
When going up and down the stairs, there is less possibility 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 stairs going up and down can be increased.

According to the foot structure of the third aspect of the present invention, when the robot walks on a substantially flat surface according to the information of the control means for controlling the walking of the robot, the foot main body is used. Since the movable foot piece is configured to be held at the non-ground position so that only the ground surface of each fixed ground portion becomes an effective ground surface, the stability when walking on a flat walking surface is particularly improved. Can be increased.

According to the foot structure of the fourth aspect of the present invention, when the robot walks on the stairs, the movable foot piece is positioned at the groundable position according to the information of the control means for controlling the walking of the robot. , The operation mechanism is operated so as to be located at the position, so that the stability particularly when going up and down stairs can be enhanced.

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

[Brief description of the 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 the foot structure of the present invention.

FIG. 4 is a bottom view of the foot structure of the embodiment shown in FIG. 3;

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

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

FIG. 7 is a longitudinal sectional view showing an example of an operation state of the foot structure of the embodiment shown in FIG. 3 at the same position as in FIG. 5;

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

FIG. 9 is a schematic illustration showing a foot state 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 foot structure according to a second embodiment of the present invention.

11 is a longitudinal sectional view taken along line XI-XI in 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 longitudinal sectional view taken along line XV-XV in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Robot 2 Movable leg 22, 22L, 22R Foot 26 Control unit 38 as a control means 38 Ground sensor 72 Actuation mechanism 74 Actuator 100 Foot main body 102A, 102B Movable foot 106A, 106B, 106C, 106D Fixed ground part 109 Grounding surface 114 Groundable surface

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor ▲ Taka ▼ Hideaki Hashimoto 1-4-1, Chuo, Wako-shi, Saitama Pref. Inside Honda R & D Co., Ltd. (72) Takashi Matsumoto 1-4-4 Chuo, Wako-shi, Saitama No. 1 Inside Honda R & D Co., Ltd. (56) References JP-A-4-122586 (JP, A) JP-A-3-1844781 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) B25J 5/00

Claims (5)

(57) [Claims] 1. A foot structure of a legged walking robot having a plurality of movable legs and providing a foot at the tip of each movable leg so as to be free to walk, wherein a foot connected to each movable leg is provided. An operation mechanism for attaching at least one movable foot piece movable in a direction that changes the area of the effective contact surface with respect to the walking surface to each of the flat main bodies, and moving the movable foot piece in the direction, The foot structure of the legged walking robot, which is provided on the flat body. 2. An effective grounding surface is provided on the lower surface of each of the foot main bodies at positions on both sides of a vertical plane including the center of the ankle joint in the traveling direction of the robot and at both front and rear ends in the traveling direction of the robot. The movable foot piece has a groundable surface to be an effective ground surface by moving the movable foot piece, and the movable foot piece has a A groundable position in which the groundable 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 traveling direction; The foot structure of a legged walking robot according to claim 1, wherein the foot structure is configured to be able to move between a non-ground position and a plane separated from the plane. 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 ground surface of each fixed ground portion of the foot body is effective. The foot structure of a legged walking robot according to claim 2, wherein the movable foot piece is held at a non-ground position so as to serve as a ground surface. 4. When the robot walks on the stairs according to information of a control means for controlling the walking of the robot, the operating mechanism operates so that the movable foot piece is located at a position where the robot can touch the ground. 3. The foot structure of a legged walking robot according to claim 2, wherein the foot structure is configured to cause the walking. 5. The apparatus according to claim 1, further comprising a contact detecting means for detecting whether or not the foot is in contact with the walking surface, and operating the operating mechanism in a state in which the foot is not in contact with the walking surface. The foot structure of a legged walking robot according to item 1.