JPH05318337A - Flat leg structure of leg type walking robot - Google Patents

Abstract

PURPOSE:To prevent effectively the production of difficulties in which walking becomes difficult due to conditions on walking such as walking up and down stairs and walking at high speed. CONSTITUTION:Flat leg pieces 102A to 102D capable of moving in a direction that a ratio A/B of a distance A between the center of a tarsus joint and the rearmost of a robot in advancing direction and a distance between the center of the tarsus joint and the front end of it in advancing direction is varied are provided on a flat leg main body 100. Each movable flat leg piece is operated by an operation mechanism 72 to vary the ratio of A/B.

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 Application 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 in addition to that, the situation of the walking surface such as the ground to be walked, the surrounding situation, and walking. It is often difficult to secure stability during walking depending on the speed and the like. That is, it is relatively easy to maintain stability when walking at low speed on a horizontal plane, but when walking up and down stairs or when walking speed is fast, walking with two legs is unstable. It is easy to become.

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 size may adversely affect the stability depending on the walking situation. For example, if the walking surface is a staircase, there are often stair-shaped protrusions on the steps of each staircase. In such a case, if the foot is large, the staircase-like part will be formed when the stairs are raised. There is a strong risk that the toe side of the foot will interfere and fall. In addition, even if the walking speed is high, if the foot is large, it is easy to interfere with each other and fall easily. In addition to this, various situations are possible, but in any case, simply designing a large foot,
It is not a fundamental solution to increase walking stability.

The present invention has been made in view of the above circumstances. Even if the condition of the walking surface or the walking speed changes,
The basic purpose is to provide a foot structure that can always maintain walking stability.

[0006]

In order to solve the above-mentioned problems, according to the present invention, basically, the first aspect is
As shown in Fig. 2, 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, the structure is coupled to each movable leg. In each of the foot flats, the projection distance A from the center position of the ankle joint to the end position of the effective contact surface with respect to the walking surface on the vertical plane parallel to the robot traveling direction and the walking surface from the center position of the ankle joint And at least one movable foot piece movable so as to change the ratio A / B of the effective ground contact surface to the foremost end of the robot in the robot traveling direction and the projection distance B on the vertical plane parallel to the robot traveling direction, and An operating mechanism for operating the movable foot piece in a direction in which the ratio A / B changes is provided in the foot body.

[0007]

In the foot structure of the present invention, as shown in FIG. 1, from the center position 23 of the ankle joint in the movable leg 2 to the rear end of the effective grounding surface 109 of the foot 22 (the rear end with respect to the robot advancing direction). Let A be the projection distance on the vertical plane parallel to the robot traveling direction up to the position of
Let B be the projection distance from the to the position of the foremost end (the foremost end in the robot advancing direction) of the effective grounding surface 109 of the foot 22 on the vertical plane parallel to the robot advancing direction. Here, if the front end and the rear end of the effective grounding surface of the foot 22 are included in a vertical plane that passes through the ankle joint center position 23 and that is parallel to the traveling direction of the robot, the ankle joint The actual spatial distances from the center position 23 to the frontmost and rearmost positions immediately correspond to the distances A and B, but in the actual foot, the front end of the effective grounding surface of the foot 22 and The position of the last end is often not included in a vertical plane that passes through the center of the ankle joint and is parallel to the robot traveling direction (for example, in the case of FIGS. 4 and 5 of the embodiment described later). In that case, With respect to the actual spatial distances from the ankle joint center position 23 to the frontmost and rearmost positions, the respective components in the direction parallel to the robot traveling direction correspond to the above-mentioned projection distances A and B. However, in the following description, in order to avoid complication, "the distance A from the center position of the ankle joint to the last end of the ground contact surface in the robot advancing direction" and "the distance from the center position of the ankle joint to the front end of the ground contact surface in the robot advancing direction" are simply described. The expression "distance B" will be used.

In the foot structure of the present invention, the ratio A / B between the distance A and the distance B can be changed by actuating the movable foot piece by the actuating mechanism. The value of the ratio A / B greatly affects the walking stability of the robot depending on the walking situation. In the structure of the present invention, the ratio A / B is selected to an optimum value that can maximize the stability of walking, for example, according to walking conditions such as stair climbing, stair descending, or walking speed. be able to.

[0009]

Embodiments of the present invention will be described below by taking a bipedal robot as an example of a legged mobile robot. FIG. 2 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, L on the left side; the same applies below), 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 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 Therefore, joint 18R (L),
The center of 20R (L) corresponds to the ankle joint center position 23 (see FIG. 1) described above. Further, thigh links 32R and 32L are provided between the waist joint and the knee joint, and lower leg links 34R and 34L are provided between the knee joint and the ankle joint.
Each is connected. 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-
No. 184782) and the like, which is not the gist of the present invention per se, so further description will be omitted.

In the robot 1 shown in FIG. 2, a well-known 6-axis force sensor 36 is provided at 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. 2) 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. 2, 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. 3 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. 4 and subsequent figures.

4 and 5 show an example of the structure of the foot 22R (22L) of the robot 1 shown in FIG. 2, that is, the foot structure of the first embodiment of the present invention. 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. 4 and 5, the foot 22 includes 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 has a mounting center position of the movable leg portion 2 (more accurately,
The length from the vertical projection position of the ankle joint) to the front end in the robot advancing direction (hence the length from the ankle to the toe) is the length from the attachment center position to the rear end in the advancing direction (hence the ankle to heel). The attachment position with respect to the movable leg portion 2 is determined so as to be longer than the length. Then, on the lower surface sides of the four corners of the foot main body 100, flat-plate-like movable foot pieces 102A, 102B, 102 which are oval in plan view are formed.
C and 102D are arranged, and these movable foot pieces 1
02A to 102D are rotatably supported by a vertical support shaft 104 in a horizontal plane (in a plane parallel to the ground plane). Each of the support shafts 104 is configured to be rotated about its axis by an operating mechanism 72 disposed at four corners on the upper surface side of the foot main body 100. As the actuating mechanism 72, in the illustrated example, a geared motor using an electric motor as an actuator (reference numeral 74 in FIG. 3), or an actuator using a pneumatic or hydraulic rotary actuator as the actuator can be applied.

Here, each support shaft 104 and each movable foot piece 10
The relative positional relationship with 2A to 102D is that each movable foot piece 10
It is determined that each support shaft 104 is eccentric with respect to the center position of 2A to 102D. Therefore, as will be described later, the movable foot pieces 102A to 102D change in the amount of protrusion to the outside from the foot main body 100 when viewed in plan when rotating.

Notched step portions 106 for accommodating the movable foot pieces 102A to 102D are formed at the four corners of the lower surface of the foot body 100, and the movable foot pieces 102A to 102D are formed. On the lower surface of the
8 is attached. In addition, in the actual foot, the lower edge portion of the elastic member 108, and further, the movable foot piece 10
The lower surface edges of 2A to 102D are often chamfered in an R shape or curved in an R shape, but R is not shown here for simplification of the drawing. Also,
When the presence or absence of the grounding state of the foot 22 is detected using the grounding sensor 38 as shown in FIG. 3, the grounding sensor 38 is usually provided on each of the movable foot pieces 102A to 102D. The ground sensor is not shown in FIGS. 4 and 5 for simplification of the drawings.

The function of the foot structure of the embodiment shown in FIGS. 4 and 5 will be described with reference to FIGS. 6 to 9. In this embodiment, the movable foot pieces 102A to 102
Only the lower surface of D, specifically, the lower surface of each elastic member 108 is an effective ground contact surface 109 for a walking surface such as a road surface during walking. The state shown in FIGS. 4 and 5 is a state in which the movable foot pieces 102A to 102D are not swung outward, and in this state, from the ankle joint center 23 to the rear end of the effective ground surface 109 in the robot advancing direction. Projection distance A,
The projected distance B to the front end is shown in FIG. In this state, the ratio A / B of the distances A and B is about 0.79 in the examples of FIGS. If any of the operating mechanisms 72 is operated from this state, the corresponding movable foot piece,
For example, 102A rotates in a horizontal plane (and thus in a plane parallel to the effective ground plane), and the notched step portion 106 of the foot main body 100 is rotated.
Then, the ratio A / B changes.
6 and 7 show a state in which the movable foot pieces 102A and 102B at the two corners on the front end side in the traveling direction of the robot are simultaneously swung forward obliquely. In this case, the ratio A / B becomes small, In the illustrated example, it is about 0.63. On the other hand, FIGS. 8 and 9 show a state in which the movable foot pieces 102C and 102D at the two corners on the rear end side with respect to the traveling direction of the robot are simultaneously swung backward obliquely. In this case, the ratio A / B Becomes larger, and A / B = 1 in the illustrated example. In this way, by appropriately rotating the movable foot pieces 102A to 102D, the ratio A / B between the distance A and the distance B can be appropriately changed.

FIG. 10 shows a flowchart for controlling the operation of the above-described foot structure according to the walking condition. In FIG. 10, in the first step 200 after starting the control, the ratio A / B at the foot is shown.
Walks in the initial state, and determines whether or not a situation in which the walking becomes difficult occurs is predicted. Such a situation where walking becomes difficult means, for example, rising stairs, descending stairs, or increasing walking speed.
This determination may be made in the third arithmetic unit 63 shown in FIG. 3 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. In this step 200, if the occurrence of a situation in which walking becomes difficult is predicted (YES),
Then, the process proceeds to next step 202. On the other hand, if it is not predicted (NO), the ratio A /
Without changing B, the initial state is maintained and the control loop ends. That is, the actuator 74 of the actuating mechanism 72 is not driven, and each movable foot piece 102A-
102D is not activated.

In step 202, it is determined whether or not the ground contact surface of the foot is separated from the walking surface. This causes the actuator 74 of the foot actuating mechanism 72 to be driven (thus, the operation of the movable foot pieces 102A to 102D) only when the foot is away from the walking surface (not in contact with the ground). This is because. That is, when the movable foot pieces 102A to 102D are operated with the foot grounded, a remarkably large load is applied to the actuator 74 of the operation mechanism 72, and the operation of the actuator 74 becomes difficult. This is because the actuator 74 may break down. In this step 202, the determination may be made by the ground detection signal from the ground sensor 38 provided in advance on the foot or the signal from the 6-axis force sensor 36. If it is determined in step 202 that the foot is not separated from the walking surface (NO), step 20
The process shifts to step 4 and waits until the foot separates from the walking surface, and after a predetermined time has elapsed, the process returns to step 202 again. 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 above-mentioned ratio A
Each movable foot piece 1 to increase or decrease the value of / B
The actuator 74 of the actuation mechanism 72 corresponding to any one or two or more of 02A to 102D is driven. In this step 206, the ratio A is calculated according to the kind of situation predicted in step 200.
There is a case where it is operated in the direction of increasing the value of / B and a case where it is operated in the direction of decreasing the value of the ratio A / B. Further, the amount of change in the value of the ratio A / B can be adjusted according to the degree of difficulty of the predicted situation. In addition, selection of increase or decrease of the value of these ratios A / B,
The settings such as the adjustment of the increase / decrease amount of the ratio A / B are normally made in step 200 described above.

Here, since an actual two-legged walking type robot is provided with 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 ratio A / B is increased or decreased in step 206, the walking motion proceeds while maintaining that state, while the next step 20
Go to 8. In step 208, it is determined whether the difficult walking condition has been resolved and the initial condition has been restored. That is, it is determined whether or not the difficult walking condition is resolved during the walking after the end of step 206.
If it is determined in step 208 that the walking has not recovered from the difficult situation (NO), step 2
After shifting to step 10, the state is maintained as it is, and after a predetermined time has passed, the process returns to step 208 again. Meanwhile, step 208
In the case where it is determined that the user has recovered from the difficult walking condition (YES), the process proceeds to step 212.

In step 212, the ratio A /
The value of the ratio A / B is decreased or increased so that the value of B is returned to the initial value. That is, the actuator 74 of the operating mechanism 72 is operated to move the movable foot pieces 102A to 102A-1.
02D is returned to the initial position. Note that step 212
Although not shown in FIG. 10, the actuator 74 of the actuating mechanism 72 is operated only when the foot is separated from the walking surface, which is not shown in FIG. When is grounded on the walking surface, the actuator 74 is operated after waiting for the user to leave 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).

When there is a situation in which walking is predicted to be difficult as described above, walking is performed while increasing or decreasing the value of the ratio A / B of the foot according to the situation, As a result, it is possible to ensure the stability of walking even under the above-mentioned situation.

Next, an example of the kind of situation in which walking is difficult and the corresponding increase / decrease in the ratio A / B value will be described with reference to FIGS. 11 to 13.

FIG. 11 shows the situation when the robot 1 climbs the stairs 300. In many cases, the staircase 300 has a protrusion 302 projecting in a cuboid pattern at the upper edge of the stepped portion. If / B is small and the tip side of the foot 22 is long as shown by the phantom line in the figure, the tip of the foot 22 may interfere with the protrusion 302 and fall. Therefore, when such a situation is predicted, the ratio A / B between the distance A on the rear end side and the distance B on the front end side of the foot 22 is increased. Specifically, in the examples of FIGS. 4 to 9, for example, the actuator 74 of the actuating mechanism 72 may be operated so that the movable foot pieces 102A and 102B on the front side in the traveling direction are retracted. When the stairs are raised in this way, it is preferable to set the ratio A / B to 1.0 or a value close thereto (however, a value not exceeding 1.0). Specifically, it is preferable to set it within the range of 0.9 to 1.0.

FIG. 12 shows the situation when the robot 1 descends the stairs 300. When descending the stairs 300, a moment that tends to fall forward in the traveling direction (stair descending direction) acts on the robot 1, so that the distance A on the rear end side of the foot 22 and the distance B on the front end side. When the ratio A / B is large and the tip side of the foot 22 is short, the robot 1 is likely to fall down. Therefore, when such a situation is predicted, the ratio A / B of the foot 22 is reduced. Specifically, in the example of FIGS. 4 to 9, for example, the actuator 74 of the actuating mechanism 72 may be operated so as to swing the movable foot pieces 102A and 102B on the front side in the traveling direction forward.

Further, when the walking speed of the robot 1 is high, if the tip end side of the foot 22 is long, interference is likely to occur and it is easy to fall. Further, in this case, the tilting angle of the foot 22 from the swing up of the foot 22 of the movable leg on the free leg side to the landing is large, and the operating moment of the movable leg is also large. That is, in walking of a general bipedal type robot, as shown in FIG. 13, when the foot 22 is separated from the walking surface, the foot 22 is first raised from the heel side, and the foot 22 is moved in the opposite direction in the air.
It is normal to tilt the foot to land again from the heel side, and then lower the toe side. It becomes noticeable when the walking speed is high, and it is easy to fall. Therefore, when walking at a high speed, the ratio A / B between the distance A on the rear end side of the foot 22 and the distance B on the front end side is reduced to reduce the risk of interference and to increase the tilt angle of the foot. To improve stability and reduce the risk of tipping. In this case, if the walking speed is expected to exceed a predetermined speed, the equivalent ground contact area of the foot 22 may be controlled to be reduced. Of course, the equivalent ground area may be changed stepwise according to the walking speed.

Next, several other embodiments of the foot structure according to the present invention, particularly an embodiment in which the mechanical portion is modified, are shown in FIG.
~ It demonstrates with reference to FIG.

FIG. 14 shows the operating foot pieces 102A to 102D.
An example in which the actuating mechanism 72 for actuating the is different from the embodiment of FIGS. 4 and 5 is shown. In this case, the support shaft 104 of each movable foot piece 102A to 102D and each movable foot piece 10
An actuator 74 such as an electric motor or a fluid pressure rotary actuator provided corresponding to 2A to 102D
The worm gear 402 is interposed as a transmission mechanism between the rotary shaft 404 and the rotary shaft 404.

In the example shown in FIG. 14, as in the examples shown in FIGS. 4 and 5, when the actuator 74 is driven, the movable foot pieces 102A to 102 are moved through the worm gear 402.
D is individually rotated in a plane parallel to the ground plane, so that the value of the ratio A / B can be changed. Further, in this example, the worm gear 402 is interposed as a transmission mechanism between the actuator 74 and each of the movable foot pieces 102A to 102D, and the reaction force from the walking surface applied to the ground surface when the foot touches the rotary shaft 404. Is absorbed by the bending of the actuator 74, the reaction force is directly absorbed by the actuator 74.
In addition, it is possible to prevent the load of the actuator 74 from increasing significantly and causing a failure.

In FIG. 15, the embodiment shown in FIG. 14 is further modified so that the two movable foot pieces 102A and 102B on the front side in the traveling direction of the robot are simultaneously operated, and the rear end of the robot in the traveling direction is moved. Two movable foot pieces 102C on the side,
An example in which the actuating mechanism 72 is configured to actuate 102D simultaneously is shown. In FIG. 15, a rotary drive type actuator 74A common to the two movable foot pieces 102A and 102B on the front side in the moving direction of the robot, and two movable foot pieces 102 on the rear side in the moving direction of the robot are shown.
A rotary drive type actuator 74B common to C and 102D is provided. Actuator 7
The rotational driving force of 4A is transmitted via the bevel gear mechanism 406A to the two worm gears 402A having a common shaft on the drive side.
402B, these worm gears 402A,
By 402B, the rotating foot pieces 102A and 102B are simultaneously rotated in opposite directions.
Similarly, the rotational driving force of the actuator 74B also has a common shaft on the driving side via the bevel gear mechanism 406B.
The worm gears 402C and 402D are provided so that the worm gears 402C and 402D can simultaneously rotate the movable foot pieces 102C and 102D in opposite directions.

In the example shown in FIG. 15, the movable foot pieces 102A and 102B on both sides of the front of the foot 22 in the advancing direction can be simultaneously advanced forward in the advancing direction to reduce the value of the ratio A / B. It is possible to increase the value of the ratio A / B by moving the movable foot pieces 102C and 102D to the rear side in the traveling direction at the same time on both sides of the foot 22 in the traveling direction.

Also in the example shown in FIG. 15, the actuators 74A to 74D; 74E and the movable foot pieces 102 are also included.
Bevel gear mechanisms 406A and 406B and worm gears 402A to 402D are interposed as transmission mechanisms between A and 102D, and in this case as well, the reaction force received from the walking surface to the ground contact surface by the bending of each intermediate shaft is absorbed. You can

In each of the above examples, the movable foot piece 102A is used.
The movable foot pieces 102A to 102D are configured so that the value of the ratio A / B is changed by rotating the surface of the movable foot piece 102D in a horizontal plane (in a plane parallel to the ground plane).
Of course, the moving direction of D is not limited to this. 16 to 23 show an example in which the operating mechanism 72 is configured to change the ratio A / B by linearly moving the movable foot pieces 102A to 102D in a plane parallel to the ground contact surface.

First, in the embodiment shown in FIGS. 16 to 18, the movable foot pieces 102A to 102D, which are rectangular in plan view, are formed on the lower surfaces of the four sides of the foot main body 100, for example.
Are arranged. These movable foot pieces 102A-10
Elastic materials 108 are attached to the lower surfaces of 2D,
The lower surface of the elastic material 108 is an effective grounding surface 109. The tips of the advancing and retracting shafts 500A to 500D are fixed to the movable foot pieces 102A to 102D, respectively, and the movable foot pieces 102A to 102D move in the radial direction of the foot body 100 by advancing and retracting the advancing and retracting shafts 500A to 500D. And the value of the ratio A / B is changed. As the actuator 74 of the operating mechanism 72 for advancing / retreating each of the advancing / retreating shafts 500A to 500D, a fluid pressure cylinder driven by fluid pressure such as air pressure or hydraulic pressure is used as shown in FIG.

FIG. 19 shows each movable foot piece 102A-10.
A rotary drive type actuator such as an electric motor is used as the actuator 74 of the actuating mechanism 72 for linearly moving the 2D forward and backward, and the rotary drive force of the actuator 74 is converted into a linear drive force by the screw screw mechanism 504 and transmitted. An example of the structure configured to do so will be described for the portion of the movable foot piece 102A corresponding to FIG. In FIG. 19, a female screw portion 508 formed on the advancing / retreating shaft 500A is screwed onto a screw shaft 506 rotated by a rotary drive type actuator 74. Therefore, the forward / backward movement of the shaft
A moves back and forth, and along with this, the movable foot piece 102A also moves back and forth. Although not shown in FIG. 19, the operating mechanisms for the other movable foot pieces 102B to 102D have the same configuration.

FIG. 20 shows each movable foot piece 102A-10.
A rotary drive type actuator such as an electric motor is used as the actuator 74 of the actuating mechanism 72 for linearly moving the 2D forward and backward, and the rotary drive force of the actuator 74 is used as the rack-pinion mechanism 5 as in the example of FIG.
An example of a configuration in which 10 is converted to a linear driving force and transmitted will be shown for the movable foot piece 102A corresponding to FIG. In FIG. 20, a pinion 512 rotated by a rotary drive type actuator 74.
Further, the rack 514 integrated with the advancing / retreating drive shaft 500A is meshed, and therefore the advancing / retreating shaft 500A advances / retreats by the rotational driving of the actuator 74, and the movable foot piece 102A also advances / retreats with this. The other movable foot pieces 102B to 102D are similarly configured.

21 to 23, two movable foot pieces 102A and 102B on both sides in front of the robot in the advancing direction are linearly moved back and forth at the same time, and two movable foot pieces on both sides in the advancing direction of the robot are on the same side. An example is shown in which the pieces 102C and 102D are linearly moved back and forth simultaneously. 21 to 23
In the four side portions of the foot main body 100 having a rectangular shape in plan view, a movable foot piece 102 is provided on the lower surface side at a position corresponding to both left and right sides of one side on the front end side in the traveling direction of the robot.
A and 102B are arranged, while movable foot pieces 102C and 102D are arranged on the lower surface side at positions corresponding to the left and right sides of one side on the rear end side in the traveling direction of the robot. An elastic material 108 is adhered to the lower surface of each of the movable foot pieces 102A to 102D as described above, and the lower surface serves as an effective grounding surface 109. A convex or concave guided portion 531 is formed on both upper sides of the movable foot pieces 102A and 102B. Correspondingly, the guided portion 531 can linearly slide on the foot main body 100. Portion 532 that engages with
Are formed. These guide portions 532 guide the movable foot pieces 102A and 102B in a direction parallel to the traveling direction of the robot (front-rear direction), and a reaction force from the walking surface applied to the movable foot pieces 102A and 102B at the time of contact with the ground. It is for receiving. On the other hand, the movable foot pieces 102C and 102D on the rear end side in the moving direction of the robot are also configured to be guided and supported by the foot main body 100 along the moving direction of the robot. Are omitted for convenience of the drawings.

Movable foot piece 1 on the front end side in the traveling direction of the robot
02A and 102B are a single and common rotary drive type actuator 74F, for example, an operating mechanism 7 including an electric motor.
The robot 2F is configured to be linearly moved forward and backward in the front-rear direction of the moving direction of the robot by the 2F. That is, the rotational driving force of the actuator 74F is the bevel gear mechanism 5
34 is transmitted to the intermediate common rotating shaft 536, and the rotating force of the intermediate rotating shaft 536 is transmitted to the bevel gear mechanism 538A,
The rotation of the screw shafts 540A, 540B transmitted to the screw shafts 540A, 540B via the 538B is converted into a linear motion by the female screw blocks 542A, 542B screwed to the screw shafts 540A, 540B, and these female screw screws are rotated. The movable foot pieces 102A and 102B fixed to the blocks 542A and 542B are linearly moved back and forth. On the other hand, the movable foot pieces 102C and 102D on the rear end side in the moving direction of the robot are also linear in the front-rear direction in the moving direction of the robot at the same time by the single and common rotary drive type actuator 74G, for example, the operating mechanism 72G equipped with an electric motor. It is configured to be moved back and forth. That is, the rotational driving force of the actuator 74G is transmitted to the intermediate common rotating shaft 536 via the bevel gear mechanism 534, and the rotating force of the intermediate rotating shaft 536 is further transmitted to the bevel gears 538C, 5C.
38D is transmitted to the screw shafts 540C and 540D, and the rotation of the screw shafts 540C and 540D is
The female foot blocks 542C and 542D screwed onto the screw shafts 540C and 540D are converted into linear motions, and the movable foot pieces 102C and 102D fixed to the female screw blocks 542C and 542D are moved rectilinearly.

In the embodiment shown in FIGS. 21 to 23, the movable foot pieces 102A, 10A on the front end side in the traveling direction of the robot are driven by driving the actuator 74F.
The ratio A / B can be changed by simultaneously moving 2B forward and backward in the moving direction of the robot. Conversely, the value of the ratio A / B is also changed by driving the actuator 74G to simultaneously move the movable foot pieces 102C and 102D on the rear end side of the robot in the moving direction backward and backward. be able to.

Next, in FIGS. 24 and 25, the movable foot pieces 102E to 102H are rotated with respect to the foot main body 100 about an axis (horizontal axis parallel to the ground plane) that is horizontal. The movable foot pieces 102E to 102H are undulated with respect to the extension surface of the effective grounding surface 109 of the foot body 100, thereby changing the value of the ratio A / B. Show.

In FIGS. 24 and 25, the foot main body 100 is formed in a flat plate shape which is rectangular in plan view, and the bottom surface of the foot main body 100 is on the front end side and the rear end side in the robot advancing direction. An elastic material 108 is attached to each, and the lower surface of the elastic material 108 serves as an effective ground surface 109. A movable foot piece 102E is attached to the front end of the foot main body 100 in the advancing direction so as to be rotatable about a horizontal support shaft 600 that is orthogonal to the advancing direction of the robot. On the other hand, a movable foot piece 102F is attached to the rear end of the foot main body 100 in the advancing direction so as to be rotatable about a horizontal support shaft 602 which is orthogonal to the advancing direction of the robot. Further, on the left and right sides of the rear part of the foot body 100 in the traveling direction, a support shaft 60 parallel to the traveling direction of the robot and horizontal is provided.
Movable foot pieces 102G and 102H are attached so as to be rotatable around 4,606. Elastic materials 108 are also attached to the back surfaces of the movable foot pieces 102E to 102H, respectively.

A movable foot piece 10 at the front end of the robot in the traveling direction.
2E is configured to be rotated (i.e., undulated) between an upright state and a horizontal state by an operating mechanism 72H including a rotary drive type actuator 74H such as an electric motor (including a geared motor). In particular,
The rotary drive type actuator 74 is attached to the foot body 100.
H is fixed, and the screw shaft 608 having a vertical axis is rotated by its actuator 74H. And this screw shaft 60
A female screw block 610 is screwed into the shaft 8, and the female screw block 610 and the movable foot piece 102E are connected by a link piece 612. Here, if the actuator 74H is driven, the screw shaft 608
The female screw block 610 ascends and descends with the rotation, and the movable foot piece 102E is undulated by the link piece 612. On the other hand, the movable foot piece 102 at the rear end of the robot in the traveling direction
F and movable foot pieces 10 on both sides of the rear end of the robot in the traveling direction
2G and 102H are those movable foot pieces 102F to 10F.
Actuator 7 including a rotary drive type actuator 74I such as an electric motor (including a geared motor) common to 2H
2I is configured to rotate (that is, undulate) between an upright state and a horizontal state. Specifically, the rotary drive type actuator 74I is fixed to the foot body 100.
The screw shaft 614 having a vertical axis is rotated by I. A female screw block 616 is screwed onto the screw shaft 614, and the female screw block 616 and each movable foot piece 1 are further attached.
Link pieces 618 and 6 between 02F and 102H, respectively.
They are connected by 20,622. When the actuator 74I is driven, the female screw block 616 moves up and down as the screw shaft 614 rotates, and the movable foot piece 102F is moved by the link pieces 618, 620, 622.
˜102H is undulated at the same time.

In this embodiment, by driving the actuator 74H, the movable foot piece 102E at the front end in the robot advancing direction is undulated with respect to the extension surface of the effective grounding surface 109 of the foot main body 100, whereby the front of the robot advancing direction. The value of the ratio A / B can be changed by enlarging / reducing the ground contact surface to the side. On the other hand, the actuator 74
By driving I, the movable foot pieces 102F to 102G on the rear side in the robot advancing direction are simultaneously undulated with respect to the extension surface of the effective grounding surface 109 of the foot main body 100, whereby the rear side with respect to the robot advancing direction. Also, the value of the ratio A / B can be changed by digitally reducing / enlarging the ground plane toward both sides of the rear end portion.

[0045]

According to the invention of claim 1, in a foot structure of a legged walking robot, each of which is provided with a plurality of movable legs, and a foot is provided at a tip of each movable leg to allow walking. , A projection distance A on a vertical plane parallel to the robot advancing direction from the center position of the ankle joint to the position of the rearmost end of the effective contact surface with respect to the walking surface in the robot advancing direction on each of the foot bodies connected to the movable legs. And at least one of which is movable so as to change the ratio A / B of the distance from the center position of the ankle joint to the front end of the effective ground contact surface with respect to the walking surface and the projection distance B on the vertical plane parallel to the robot advancing direction. Since a movable foot piece is attached and an operating mechanism for operating the movable foot piece in the direction in which the ratio A / B changes is provided in the foot body, the robot walking condition,
For example, the value of the ratio A / B can be changed so as to maximize the stability of walking according to walking conditions such as rising and falling of stairs, walking speed, and the like, and thus various walking conditions are difficult. It is possible to dramatically improve the stability of walking even under the above conditions.

According to the second 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 significant 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.

According to the invention of claim 3, according to the information of the control means for controlling the walking of the robot, when the walking speed exceeds a predetermined value, the ratio A / B is increased to increase the operating mechanism. Since it is operated, it is possible to reduce the risk that the foot of the free leg interferes with each other when walking at a high speed, and to reduce the tilt angle of the foot of the free leg to reduce The moment can be reduced, and therefore the stability during high-speed walking can be increased, and the occurrence of a situation in which the robot falls down can be effectively prevented.

According to the fourth aspect of the present invention, the actuating mechanism is operated in the direction of increasing the ratio A / B when walking up the stairs in accordance with the information of the control means for controlling the walking of the robot. Therefore, even when climbing a staircase in which there is an uneven projection at the upper end of the step portion of the stairs, it is possible to prevent the toe side portion of the foot from interfering with the projection, When the operating mechanism is operated so that the ratio A / B is within the range of 0.9 to 1.0 when walking up the stairs as in the invention of claim 5, It is possible to reliably prevent a situation in which the flat toe side portion interferes with the protrusion and falls.

According to the sixth aspect of the present invention, the operating mechanism is operated in a direction to reduce the value of the ratio A / B when walking down the stairs according to the information of the control means for controlling the walking of the robot. Therefore, it is possible to increase the stability of the robot at the time of descending the stairs and prevent the robot from falling down.

According to the invention of claim 7, a transmission mechanism is interposed between the actuator of the actuating mechanism and the movable foot piece, and the transmission mechanism is applied to the ground surface when the foot is grounded. Since the reaction force is configured not to be directly transmitted to the drive shaft, it is possible to effectively prevent the actuator of the operating mechanism from malfunctioning due to the reaction force.

According to the invention of claim 8, the movable foot piece is
Since it is slidable linearly in a plane parallel to the effective ground plane, the movable foot piece can be slid linearly according to the situation to change the value of the ratio A / B. The stability of walking of the robot can be increased, and in this case, the value of the ratio A / B can be changed in an analog manner, so that the ratio A can be set to an optimum value according to the situation.
/ B can be set.

According to the invention of claim 9, the movable foot piece is
Since it is attached to the foot main body so that it can rotate about an axis perpendicular to the effective ground plane in a plane parallel to the effective ground plane, the movable foot piece can be rotated depending on the situation. The stability of the robot can be increased by changing the ratio A / B by using the ratio A / B. In this case as well, the ratio A / B can be set to an optimum value according to the situation, as in the case of the invention of claim 13. Can be set.

According to the tenth aspect of the invention, the movable foot piece is rotatable about an axis parallel to the effective ground surface so that the movable foot piece can be undulated with respect to the extension surface of the effective ground surface of the foot body. Since it is attached, by raising and lowering the movable foot piece according to the situation and changing the value of the ratio A / B,
The walking stability of the robot can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an outline of a leg walking robot in the vicinity of a foot for explaining the operation of the present invention.

FIG. 2 is a schematic diagram generally showing an example of a control device for a legged walking robot according to the present invention.

FIG. 3 is an explanatory block diagram of a control unit shown in FIG.

FIG. 4 is a plan view showing an example of a foot structure according to an embodiment of the present invention in which a movable foot piece is configured to rotate in a horizontal plane.

FIG. 5 is a vertical cross-sectional front view taken along the line VV of the foot structure shown in FIG.

FIG. 6 is a plan view showing an example of an operating condition of the foot structure shown in FIG.

7 is a vertical cross-sectional view taken along line VII-VII of FIG.

FIG. 8 is a plan view showing another example of the operating condition of the foot structure shown in FIG.

9 is a vertical sectional view taken along the line IX-IX in FIG.

FIG. 10 is a flowchart showing an example of a control flow for the operation of the foot structure of the present invention.

FIG. 11 is a schematic diagram showing a situation of a two-legged robot to which the foot structure of the present invention is applied when climbing stairs.

FIG. 12 is a schematic diagram showing a situation of a two-legged robot to which the foot structure of the present invention is applied when descending stairs.

FIG. 13 is a schematic diagram showing a situation of high speed walking of a two-legged robot with respect to the related art.

14 is a plan view showing an embodiment in which the operating mechanism of the foot structure shown in FIG. 4 is changed.

15 is a plan view showing another embodiment of the foot structure shown in FIG. 4 in which the operating mechanism is changed.

FIG. 16 is a plan view showing an example of a foot structure according to an embodiment of the present invention in which a movable foot piece is linearly moved in a horizontal plane.

17 is a front view of the foot structure shown in FIG. 16. FIG.

18 is an enlarged sectional view taken along line XVIII-XVIII in FIG.

19 is a cross-sectional view showing an example of the foot structure shown in FIG. 16 in which the operating mechanism is changed, at the same position as in FIG.

20 is a cross-sectional view showing another example of the foot structure shown in FIG. 16 in which the actuating mechanism is changed, at the same position as in FIG.

FIG. 21 is a plan view showing an example of a foot structure according to an embodiment of the present invention in which a movable foot piece is linearly moved in the front-rear direction of the traveling direction of the robot.

22 is a front view of the foot structure of FIG. 21. FIG.

23 is a vertical cross-sectional view taken along line XXIII-XXIII in FIG.

FIG. 24 is a partially cutaway perspective view showing an example in which a movable foot piece is undulated as a foot structure of an embodiment of the present invention.

25 is a vertical sectional view taken along line XXV-XXV in FIG.

[Explanation of symbols]

1 Robot 2 Movable legs 22 Foot 23 Ankle joint center 72 Actuating mechanism 74, 74A, 74B, 74F, 74G, 74H, 74
I actuator 100 foot main body 102A, 102B, 102C, 102D, 102E,
102F, 102G, 102H Movable foot piece 109 Effective ground 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 inside Honda R & D Co., Ltd. (72) Inventor Akira Takeno 1-4-1 Chuo, Wako, Saitama Inside Honda R & D Co., Ltd.

Claims (10)

[Claims] 1. A foot structure of a legged walking robot which is provided with a plurality of movable legs, each of which has a foot at the tip of each movable leg, and is connected to each movable leg in a foot structure. In each of the foot flats, the projection distance A from the center position of the ankle joint to the position of the last end of the effective contact surface with respect to the walking surface on the vertical plane parallel to the robot traveling direction and the ankle joint center position to the walking surface Ratio of the effective ground contact surface to the foremost end of the robot in the traveling direction and the projection distance B on the vertical plane parallel to the robot traveling direction A /
At least one movable foot piece movable so as to change B is attached, and the movable foot piece is set to the ratio A / B.
A foot structure of a legged walking robot, characterized in that an actuating mechanism for actuating in a changing direction is provided on the foot body. 2. 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. 3. The actuating mechanism is operated in a direction to increase the ratio A / B when the walking speed exceeds a predetermined value according to the information of the control means for controlling the walking of the robot. The foot structure of the legged walking robot according to Item 1. 4. The operation mechanism according to claim 1, wherein the operating mechanism is operated in a direction to increase the ratio A / B when walking up the stairs in accordance with information from a control unit that controls walking of the robot. Structure of the human legged walking robot. 5. The ratio A / when walking up stairs.
The foot structure of the legged walking robot according to claim 4, wherein the actuating mechanism is operated so that B is within a range of 0.9 to 1.0. 6. The operating mechanism according to claim 1, wherein the operating mechanism is operated in a direction to reduce the ratio A / B when walking down stairs in accordance with information from a control means for controlling walking of the robot. Structure of the human legged walking robot. 7. A transmission mechanism is interposed between the actuator of the actuating mechanism and the movable foot piece, and the transmission mechanism is applied from the walking surface to the effective grounding surface of the foot when the foot touches the ground. The foot structure of the legged walking robot according to claim 1, wherein the foot structure is configured not to directly transmit a reaction force to the actuator. 8. The foot of the legged walking robot according to claim 1, wherein the movable foot piece is linearly slidably attached to the foot body in a plane parallel to the effective ground plane. Construction. 9. The movable foot piece is attached to the foot body so as to be rotatable about an axis in a direction orthogonal to the effective ground plane in a plane parallel to the effective ground plane. The foot structure of the legged walking robot described in 1. 10. The movable foot piece is rotatably attached about an axis parallel to the effective ground surface so that the movable foot piece can rise and fall with respect to an extension surface of the effective ground surface of the foot body. The foot structure of the legged walking robot described in 1.