JP2012125911A - Legged robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a legged robot which can move stably, is resistant to shock and can move at high speed.SOLUTION: In the legged robot provided with four legs in its base, the tips on the ground sides of the legs are provided with two wheels respectively. Thereby, the leg grounding area becomes wide and stable move becomes possible. Moreover, it is made possible for wheels provided on the same leg to relatively change the numbers of revolutions. As a result, a difference between inner and outer rings, which arises when it curves, is eased, and slippage is hard to occur between the wheels and the ground contact surface. Furthermore, since a shock absorbing member is provided between an axle supporting the wheel and a housing, shock is absorbed. Therefore, it also can cope with high-speed move in which shock is large.

Description

  The present invention relates to a legged robot capable of walking and moving up and down stairs with a plurality of legs, and more particularly to a legged robot suitable for supporting the movement of a guided person.

  Conventionally, a legged robot having a plurality of legs on a base is known. In Patent Document 1, a wheel that rotates about each axis is attached to the tip of the leg portion on the ground contact surface side in order to improve the directionality and mobility when moving straight / translate. With such a configuration, the flat ground can be moved by the wheel, and when there is an obstacle such as a step, it can be moved by the leg, so that the hybrid can move in a hybrid manner.

  However, the above configuration has a problem that the ground contact area of the leg portion becomes small. In other words, the wheel has a smaller contact area with the ground than the conventional leg used for movement. For this reason, when the base is supported by two or three legs during the walking motion, the center of gravity of the robot does not fall within the leg ground contact area (see FIG. 9A), and the balance is easily lost.

  On the other hand, in Patent Document 2, two legs are attached to one leg and two wheels are arranged side by side in the front-rear direction so that the stairs can be moved up and down stably. It describes a three-point supported legged robot with a single leg that has two wheels mounted side by side.

  However, since the base is supported by the two legs on the side of the base when ascending and descending the stairs, the ground contact area of the base is reduced, and if the center of gravity of the robot is placed within the ground contact area of the base in order to stabilize the base, There is a problem that a stable posture is limited.

JP 2004-34169 A JP 2005-46949 A JP 2003-325478 A JP 2007-239783 A

  In view of the above problems, an object of the present invention is to provide a legged robot that can stably walk, travel, and move up and down stairs.

The above object of the present invention can be achieved by the following constitution.
(1) A legged robot in which a plurality of legs are provided on a base, wherein at least half of the legs are provided with two or more wheels at the ground contact side tip.
(2) The legged robot according to (1), wherein the base body is provided with four legs, and two wheels are provided on every leg.
(3) When one of the leg portions is separated from the grounding surface, the contact point between the wheel and the grounding surface is moved without moving the grounding leg portion and the base body in the left-right direction relative to the traveling direction. The legged robot according to (1) or (2), wherein the center of gravity of the base body is within a leg ground contact area formed by connecting the two.
(4) The legged robot according to any one of (1) to (3), wherein the wheel is directed in a traveling direction when the legged robot is moved.
(5) The legged robot according to any one of (1) to (4), wherein the number of rotations of the wheels provided on the same leg can be changed relatively.
(6) The wheel includes a hub that is fitted to an axle that supports the wheel, and a rubber tire that is fitted to the outer periphery of the hub. At least a part of the hub in the circumferential direction is provided at both axial end surfaces of the hub. The legged robot according to any one of (1) to (5), wherein a flange portion is provided on the robot.
(7) A cylindrical body made of conductive rubber is fitted on the outer periphery of the hub and arranged in parallel with the rubber tire, and the outer diameter of the cylindrical body is set so that a part of the outer periphery of the cylindrical body is grounded. (6) The legged robot according to (6).
(8) The leg according to any one of (1) to (7), wherein a buffer member is provided between the axle and a housing provided on a leg portion that supports the axle. Type robot.

  According to the legged robot of the present invention, stable movement is possible, and the movement of the legs for stabilizing the posture can be reduced. For this reason, it is possible to move at a higher speed than in the prior art.

1 is a front view of a legged robot 100. FIG. 1 is a side view of a legged robot 100. FIG. 3 is a side view of a waist joint 13. FIG. 3 is a cross-sectional view of a wave gear device 70. FIG. 1 is an overall view of a leg portion 20. 3 is a side view of a drive wheel 60. FIG. 4 is a cross-sectional view of a drive wheel 60. FIG. It is a principal part enlarged view of FIG. It is the schematic diagram which looked at the legged robot from the top. It is the schematic diagram which looked at the legged robot from the top. It is the schematic diagram which looked at the legged robot from the top. It is the schematic diagram which looked at the legged robot from the side. FIG. 6 is a cross-sectional view showing a modified example of the drive wheel 60. It is a figure showing wheels 62a and 62b. It is sectional drawing which shows the modification of wheel 62a, 62b.

(Schematic configuration of legged robot)
First, a schematic configuration of the legged robot 100 will be described. FIG. 1 is a front view of the legged robot 100, and FIG. 2 is a side view thereof. The legged robot 100 includes a base body 10 having a substantially rectangular parallelepiped shape and four leg portions 20 connected to four corners of the base body 10.

  The base body 10 includes a front base body 11 in the front-rear direction of the base body, a rear base body 12 in the front-back direction of the base body, and a waist joint 13 that connects the front base body 11 and the rear base body 12 in a state of being relatively displaceable about a predetermined axis. And two leg portions 20 are connected to the front base body 11 and the rear base body 12, respectively.

  A first hip joint 30 and a second hip joint 40 are interposed between the base body 10 and each leg 20 in order from the base body side. The first hip joint 30 is a joint that rotates the leg portion 20 about the vertical axis of the base body 10, and the second hip joint 40 is a joint that rotates the leg portion 20 about an axis orthogonal to the vertical axis of the base body 10. is there. That is, the second hip joint 40 is a joint that rotates the leg portion 20 around the left and right axes and the front and rear axes of the base body 10 according to the rotation position of the first hip joint 30. The first hip joint 30 and the second hip joint 40 enable a three-dimensional pivot of the leg 20.

  Each leg 20 includes a base-side leg 21 on the base-side, a ground-side leg 22 on the ground-side, and the ground-side leg 22 with respect to the base-side leg 21 and an axis parallel to the second hip joint 40. And a knee joint 50 connected in a rotatable state. Therefore, the knee joint 50 is a joint that rotates the leg portion 20 around the left-right axis and the front-rear axis of the base body 10 according to the rotation position of the first hip joint 30. The second hip joint 40 and the knee joint 50 allow the leg portion 20 to bend and stretch.

  A driving wheel 60 that rotates about an axis parallel to the knee joint 50 is pivotally supported at the tip of each leg 20. A three-dimensional distance measuring device 14 is attached to the front surface of the base 10. The three-dimensional distance measuring device 14 rotates the distance sensor about two axes orthogonal to the measurement direction of the distance sensor, and based on the measurement result obtained thereby, the three-dimensional distance measuring device 14 continuously on the object existing within the measurement range. Recognize the face.

  The coordinate system (hereinafter referred to as a sensor coordinate system) of the three-dimensional distance measuring device 14 has the front-rear direction of the base 10 as the xrs axis, the left-right direction of the base 10 as the yrs axis, and the height direction of the base 10 as the zrs axis. At the origin position of the distance sensor, the measurement direction of the distance sensor coincides with the xrs axis, and the first rotation axis of the distance sensor coincides with the yrs axis. Although the direction of the first rotation axis of the distance sensor changes depending on the scanning angle around the z-axis, the first rotation axis of the distance sensor coincides with the yrs axis at the origin position. write. A leg tip front sensor 23 that detects the distance to the front object and a leg tip lower sensor 24 that detects the distance to the ground plane are provided on the distal end side of each leg 20.

Next, the configuration of the hip joint 13 will be described. FIG. 3 is a side view of the hip joint 13.
The hip joint 13 includes a wave gear device 70 generally known as a harmonic drive (registered trademark), and the front base body 11 and the rear base body 12 are relatively displaced around the roll axis of the base body 10 through the wave gear device 70. Linked in a possible state.

Here, the wave gear device 70 will be described. FIG. 4 is a cross-sectional view of the wave gear device 70.
The wave gear device 70 includes a wave generator 71 constituted by an elliptical cam serving as a rotation center and a ball bearing fitted on the cam, and an inner peripheral surface which is in sliding contact with an outer ring of the ball bearing, and teeth are formed on the outer peripheral surface. A thin cup-shaped flexspline 72 and a ring-shaped circular spline 73 that meshes with the flexspline 72 through more teeth than the flexspline 72 formed on the inner peripheral surface. Here, the flexspline 72 is connected to the front base 11, and the circular spline 73 is connected to the rear base 12.

  On the other hand, the cam of the wave generator 71 is connected to a rotating shaft 74 supported by the front base 11, and a driven pulley 75 is fixed to the rotating shaft 74. A motor M1 having a motor shaft substantially parallel to the rotating shaft 74 is fixed to the front base body 11, and a driving pulley 76 facing the driven pulley 75 in the circumferential direction is fixed to the motor shaft. By applying a timing belt or a V belt (not shown) to the driven pulley 75 and the driving pulley 76, the power of the motor M1 is transmitted to the wave generator 71. The power transmission may be a gear or a chain.

  With the above configuration, the rotation of the motor M1 is transmitted to the wave generator 71 at a predetermined reduction ratio via the pulley. The rotation of the wave generator 71 changes the meshing position of the flex spline 72 and the circular spline 73, thereby rotating the circular spline 73 at a predetermined reduction ratio. That is, the front substrate 11 and the rear substrate 12 are relatively displaced around the roll axis of the substrate 10 by the rotation of the motor M1.

  Next, the leg 20 which is a characteristic part of the present invention will be described. FIG. 5 is an external view of the entire leg portion 20. The first hip joint 30 is a box-shaped housing 31 fixed to the base body 10, and a joint that is pivotally supported by the housing 31 in a state substantially parallel to the vertical axis of the base body 10 and connected to the second hip joint 40 below the housing 31. A shaft 32 and a motor M2 that is fixed to the upper surface of the housing 31 and drives the joint shaft 32 are provided. The housing 31 houses a reduction gear (for example, a wave gear device) that transmits the rotation of the motor to the joint shaft 32 at a predetermined reduction ratio. Further, the side surface of the housing 31 has a notch in which a portion that interferes with the base-side leg 21 when the base-side leg 21 is rotated by the joint shaft 32 is removed according to the track of the base-side leg 21. A portion 33 is formed.

  The second hip joint 40 is pivotally supported by the housing 41 and connected to the base-side leg 21 in a state substantially parallel to the housing 41 fixed to the joint shaft 32 of the first hip joint 30 and the vertical axis of the base 10. And a motor (not shown) that is housed in the housing 41 and drives the joint shaft 42. The housing 41 also houses a reduction gear (for example, a wave gear device) that transmits the rotation of the motor to the joint shaft 42 at a predetermined reduction ratio.

  The base-side leg portion 21 is configured by a pair of frames that are opposed to each other so that the upper end side sandwiches the housing 41 of the second hip joint 40 and is fixed to the joint shaft 42. The knee joint 50 is pivotally supported by the housing 51 in a state of being substantially parallel to an axis perpendicular to the vertical axis of the base 10 and a box-shaped housing 51 integrally formed on the lower end side of the base-side leg 21. And a motor shaft (not shown) that is accommodated in the housing 51 and drives the joint shaft 52. The housing 51 houses a reduction gear (for example, a wave gear device) that transmits the rotation of the motor to the joint shaft 52 at a predetermined reduction ratio. Further, on the upper end side of the housing 51, when the base-side leg portion 21 rotates at the second hip joint 40, a portion that interferes with the housing 41 of the second hip joint 40 corresponds to the trajectory of the base-side leg portion 21. The inclined portion 53 removed in this manner is formed.

  The grounding side leg 22 is composed of a pair of frames that are opposed to each other so that the upper end side sandwiches the housing 51 of the knee joint 50 and is fixed to the joint shaft 52. The drive wheel 60 is pivotally supported by the housing 61 in a state of being substantially parallel to an axis perpendicular to the vertical axis of the base body 10 and a box-shaped housing 61 integrally formed on the lower end side of the grounding leg 22. Are provided with wheels 62a and 62b. Since the wheels 62 a and 62 b are positioned substantially directly below the first hip joint 30 and the second hip joint 40, the wheels 62 a and 62 b can be steered by rotation of the yaw axis of the first hip joint 30.

  FIG. 9 is a schematic view of the legged robot as viewed from above in a state where the legs are grounded. FIG. 9 (a) shows a legged robot in which one leg is provided with one wheel, and FIG. 9 (b) shows a legged robot according to the present embodiment in which each leg is provided with two wheels. Yes. The center of gravity of the legged robot is contained in a polygon S (hereinafter referred to as “leg contact area S”) formed by connecting the contact points between the wheels of each leg and the contact surface, as indicated by the dotted line in FIG. When there is a leg contact area S vertically below the center of gravity), the posture of the legged robot is stabilized (does not fall down). For this reason, since the range of movement of the center of gravity of the legged robot is widened when the leg contact area S is wide, the posture of the base body of the legged robot 100 has a high degree of freedom. In the case of FIG.9 (b), the wheel is provided in the leg part 20 2 each, and compared with the case where the wheel is provided in the leg part 20 of FIG. S increases. For this reason, as shown in FIG. 9B, the posture is more stable when two wheels are provided on the leg portion 20, and the degree of freedom of the posture of the base body 10 of the legged robot 100 is increased.

  FIG. 10 is a schematic view of a legged robot as viewed from above in a state where one of the four legs is not grounded. The wheel shown by the oblique line in the figure is a wheel that is not grounded. When one wheel is provided for each leg, if one leg is not grounded, the center of gravity is difficult to be located in the leg ground contact area S as shown in FIG. As a result, in order to stabilize the posture and prevent falling, it is positioned on the opposite side of the leg part not touching and the traveling direction (vertical direction in FIG. 10) as shown in FIGS. The legs that are not grounded, such as widening the legs, bending the legs that are on the same side of the direction of travel as the legs that are not grounded, to the legs that are not grounded, The movement which shakes in the direction is necessary. That is, it is necessary to move the base body and the leg portion relatively to the left and right to widen the leg ground contact area S and put the center of gravity within the leg ground contact area S. For this reason, the movement of the legged robot 100 becomes slow. On the other hand, when two wheels are provided on each leg as shown in FIG. 10D, the center of gravity is located in the leg ground contact area S, so that the posture of the grounded leg is stabilized. Is no longer required. As a result, the speed of movement can be increased.

  In order to increase the leg ground contact area S, it is not always necessary to provide two wheels for every driving wheel 60. Only one of the grounded driving wheels 60 is required. It is only necessary to provide two wheels. That is, in the case of a legged robot in which the diagonal legs are alternately grounded and moved, as shown in FIG. 11 (a), two wheels are attached to one drive wheel 60 of the diagonal two legs. When provided, the leg ground contact area S is substantially triangular, and a wider leg installation area S is obtained. In this case, when the center of gravity of the legged robot 100 is above the base 10 in FIG. 11 (a), it is preferable to provide two wheels on the upper driving wheel 60, and the center of gravity is below the FIG. 11 (a). In this case, it is preferable to provide two wheels on the lower drive wheel 60 in the same manner. In addition, as shown in FIG. 11B, in the case where a pair of legs move only by wheels among the legs provided in the legged robot, two wheels may be provided only on the driving wheels 60 of the legs. Good. As described above, more than half of the leg portions are more preferably leg portions having two wheels.

  FIG. 12 is a schematic view of a legged robot viewed from the side when the stairs are raised and lowered. FIG. 12A shows a state where the stairs start to rise or end, and FIG. 12B shows a state where the stairs start to rise or start to descend. When only one wheel is provided for each leg, as shown in FIGS. 10 (b) and 10 (c), each wheel is directed in the traveling direction when moving up and down the stairs (the direction in which the central axis of the wheel and the traveling direction are orthogonal to each other). Can't). For this reason, the wheel cannot be driven when the stairs are raised or lowered. However, if there are two wheels provided on each leg, the wheels are directed in the direction of travel as shown in FIG. 10 (d), so the left wheel in FIG. You can move by driving the front leg. For this reason, it is not necessary to move up and down the legs (walking motion) to move these legs, so that the stairs can be moved up and down at high speed.

When the legged robot climbs up the stairs with many steps, the legged robot climbs up several steps after recognizing the stairs, and then repeats recognition and movement up several steps. For this reason, if the legged robot keeps climbing the stairs, an error from the assumed leg ground contact position becomes large, and the error needs to be corrected to keep climbing the stairs. When one leg is provided for each leg, the wheel cannot be driven because the wheel does not face the traveling direction as described above, and this correction must be performed by walking. At that time, it is necessary to correct the walking motion of the entire leg, and a complicated program for that purpose is required, and the correcting operation also takes time. On the other hand, when there are two wheels provided on each leg, the wheels can be driven as described above, and the wheels need only be driven by an error. Therefore, the necessary program becomes simple and can be easily and quickly corrected.

(Configuration of drive wheels)
6 is a side view of the vicinity of the wheels 62a and 62b of the drive wheel 60, FIG. 7 is a cross-sectional view (as viewed in the direction of the arrow A in FIG. 6), and FIG.
The wheels 62a and 62b are attached to both ends in the axial direction of the axle 63 supported by the housing via rolling bearings 65a and 65b, and both ends of the axle 63 are nuts 68a and 68b for preventing the wheels 62a and 62b from coming off. Is attached. The axle 63 is rotationally driven through a pulley 64 by a motor (not shown).

  A key 67 is provided in the wheel fitting portion 63 b of the axle 63, and the wheel 62 b is fitted through the wheel fitting portion 63 b and the key 67. For this reason, the wheel 62 b is rotationally driven together with the axle 63. On the other hand, since the wheel fitting portion 63a is in sliding contact with the wheel 62a, the axle 63 and the wheel 62a are not entangled and the rotational speeds of both are not equal.

  As shown in FIG. 8, the wheel fitting portion 63a is in sliding contact with the wheel 62a. For this reason, even when there is a difference between the inner and outer circumferences of the wheels 62a and 62b during the curve traveling of the legged robot 100, the wheel 62b is driven by a motor to rotate and contribute to the traveling of the legged robot, while the wheel 62a is It rotates so as to roll on the ground contact surface in accordance with the movement of the wheel 62b. As a result, slippage hardly occurs between the wheels 62a and 62b and the ground contact surface, and smooth movement becomes possible. As a result, in order to increase the leg ground contact area S, energy loss required for movement is smaller than when two wide wheels having the same width are provided instead of two wheels.

  In addition, in FIG. 8, although the wheel fitting part 63a and the wheel 62a were made into sliding contact, the method of setting it as the mechanism which can change the rotation speed of the two wheels 62a and 62b is not limited to this, A wheel fitting part A rolling bearing or a sliding bearing may be provided between 63a and the wheel 62a. Also, the wheels 62a and 62b may be supported by using two axles without sharing the axles with the wheels 62a and 62b. In this case, it is good also as a mechanism which drives only one wheel, and it is good also as a mechanism which drives each wheel 62a, 62b using two motors which can change rotation speed. Moreover, it is good also as a structure which provided the differential gear mechanism between the two axles. In either case, the same effect as described above can be obtained.

  Further, buffer members 66a and 66b are attached to the outer circumferences of the rolling bearings 65a and 65b supporting the axle 63 in order to prevent the bearings 65a and 65b and the buffer members 66a and 66b from coming off. 69b. The buffer members 66a and 66b are preferably elastic materials, and more preferably urethane.

Thus, since the buffer member 66b is provided between the axle 63 and the housing 61, it is possible to absorb an impact when the wheels 62a and 62b are grounded. As a result, the legged robot 100 can perform high-speed walking movement with a large impact.

  As shown in FIG. 13, the drive wheels 60 may be configured such that the wheels 62A and 62B are supported by independent axles 63A and 63B and are individually driven by motors M3 and M4. The motors M3 and M4 are connected to and controlled by the control device 80 via the wirings 81A and 81B. Furthermore, the drive wheel 60A and the grounding side leg 22A are connected by a passive mechanism, and the grounding side leg 22A is not restricted around the axis. With such a configuration, it is possible to steer only with the drive wheels 60A.

  When walking without using the wheels 62A and 62B, if the first hip joint 30 and the motor M2 are omitted, the mobility is lowered. However, when moving using the wheels 62A and 62B, the hip joint 30 and the motor M2 can be omitted without reducing the mobility by using the configuration of this example.

(Composition of wheel)
As shown in FIG. 7, the wheels 62a and 62b include hubs 62a1 and 62b1 supported by the axle 63, and rubber tire portions 62a2 and 62b2 that are fitted and fixed to the hubs 62a1 and 62b1. By providing the rubber tire portions 62a2 and 62b2, it is possible to absorb an impact at the time of ground contact, and the legged robot 100 can also perform high-speed walking movement with a large impact. Further, when the impact can be sufficiently absorbed only by the rubber tire portions 62a2 and 62b2, the above-described buffer member 66b can be omitted.

  The outer peripheral surfaces of the hubs 62a1 and 62b1 in FIG. 7 have a uniform cylindrical shape. As shown in FIG. 14, flange portions 62a3 and 62b3 are provided at both ends in the axial direction, and rubber tires 62a2 and 62b2 are fitted thereto. May be bonded and fixed. Such a configuration makes it difficult for the rubber tires 62a2 and 62b2 to come off the hubs 62a1 and 62b1. In FIG. 14, the flange portions 62a3 and 62b3 are provided in the entire circumferential direction of the hubs 62a1 and 62b1, but may be provided in at least a part of the circumferential direction.

  Further, in such wheels 62a and 62b, cylindrical conductive rubbers 62a4 and 62b4 may be juxtaposed with the rubber tires 62a2 and 62b2, as shown in FIG. Here, the conductive rubbers 62a4 and 62b4 have the same outer diameter as the rubber tires 62a2 and 62b2, and are grounded. 7 and 14, the legged robot 100 is insulated from the ground by the rubber tires 62a2 and 62b2. For this reason, when there is a potential difference between the human and the legged robot 100, when the human touches the legged robot 100, electricity may flow to the human. On the other hand, in FIG. 15, the legged robot 100 is grounded to the ground by the conductive rubbers 62a2 and 62b2. As a result, by eliminating the potential difference between the human and the legged robot 100, electric shock at the time of contact can be prevented. In such a case, it is preferable that the flange portions 62a3 and 62b3 are fitted and fixed to the outer periphery. Accordingly, the conductive rubbers 62a4 and 62b4 can be provided without reducing the axial dimension of the rubber tires 62a2 and 62b2. Note that at least a part of the conductive rubber may be grounded.

  The legged robot according to the present invention as described above is suitable for guiding a guided person because it can quickly walk and travel. Also, it is suitable for guiding the guided person in that it is not necessary to move the leg part to the left and right during walking movement, and the space in the left-right direction necessary for the movement is smaller than that of the conventional one.

  In the above embodiment, the description has been made centering on the four-legged robot. However, the present invention is not limited to this, and any legged robot having a plurality of leg portions can be suitably used. In this case, it is preferable to provide two wheels on at least half of the plurality of leg portions. In the above description, two wheels are used, but two or more wheels may be used. Furthermore, there is no problem in applying the above embodiment to Japanese Patent Application Laid-Open No. 2010-5718 filed by the inventors of the present invention.

DESCRIPTION OF SYMBOLS 100 Leg type robot 10 Base body 11 Front base body 12 Rear base body 13 Lumbar joint 14 Three-dimensional distance measuring device 20 Leg part 21 Base side leg part 22 Grounding side leg part 23 Leg tip front sensor 24 Leg tip lower sensor 30 First hip joint 31 Housing 32 Joint shaft 33 Notch 40 Second hip joint 41 Housing 42 Joint shaft 50 Knee joint 51 Housing 52 Joint shaft 60 Driving wheel 61 Housing 62a, 62b Wheel 63 Axle 64 Pulley 65a, 65b Rolling bearing 66a, 66b Buffer member 67 Key 68a , 68b Nut 69a, 69b Plate 70 Wave gear device 71 Wave generator 72 Flex spline 73 Circular spline 74 Rotating shaft 75 Driven pulley 76 Drive pulley M1-4 Motor

Claims (8)

In a legged robot provided with a plurality of legs on the base body,
A legged robot characterized in that at least half or more of the legs are provided with two or more wheels at the ground contact side tip. The legged robot according to claim 1, wherein the base is provided with four legs, and two wheels are provided on every leg. When one of the legs is separated from the ground plane,
Without relatively moving the grounded leg and the base body in the left-right direction with respect to the traveling direction,
3. The legged robot according to claim 1, wherein the center of gravity of the base body falls within a leg ground contact area formed by connecting a contact point between the wheel and the ground contact surface. The legged robot according to any one of claims 1 to 3, wherein when the legged robot moves, the wheels are directed in a traveling direction. 5. The legged robot according to claim 1, wherein rotation speeds of the wheels provided on the same leg portion can be relatively changed. The wheel includes a hub that is fitted to an axle that supports the wheel, and a rubber tire that is fitted to an outer periphery of the hub. At both end surfaces in the axial direction of the hub, a flange portion is provided at least in a circumferential direction of the hub. The legged robot according to claim 1, wherein a legged robot is provided. A cylindrical body made of conductive rubber is fitted to the outer periphery of the hub and is arranged side by side with the rubber tire, and the outer diameter of the cylindrical body is set so that a part of the outer periphery of the cylindrical body is grounded. The legged robot according to claim 6. The legged robot according to any one of claims 1 to 7, wherein a buffer member is provided between the axle and a housing provided on a leg portion that supports the axle.

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