Four legged walking robot

Abstract

To provide a robot capable of walking on four legs without providing a driving source for bending in leg parts.SOLUTION: The four legged walking robot includes four leg portions 3, 4, 5, and 6 which are connected to a connecting shaft 21 of a main body 2 so as to be rotatable relative to the connecting shaft 21 and have joints 3A, 4A, 5A, and 6A in intermediate portions, a first drive source which is provided in the main body 2 and generates power for bending and extending the joints 3A, 4A, 5A, and 6A, a second drive source which is provided in the main body 2 and generates power for rotating the leg portions 3, 4, 5, and 6 around the connecting shaft 21, and a controller which controls the first and second drive sources.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a quadruped walking robot. [Background technology]

[0002] For example, Patent Document 1 discloses a quadruped walking robot having four legs connected to a main body including a seat on which a person sits astride. Each leg in Patent Document 1 has a base end rotatably connected to the main body and a bendable middle portion. A base end driving actuator for rotating the base end of the leg is built into the main body, and a bending actuator for bending the middle portion of the leg is built into the leg. Each leg is rotated at its base end by the base end driving actuator, and the middle portion of each leg is bent by the bending actuator, thereby enabling the robot to walk on four legs. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-112850 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of Patent Document 1, an actuator for bending the middle part of the leg is built into the leg, but building an actuator into the leg requires wiring for control and power supply from the main body, which makes it difficult to manage the wiring, and also makes it difficult to rotate the leg 360 degrees at its base end due to the presence of the wiring, limiting the degree of freedom of movement of the leg. Furthermore, it is necessary to provide space for building the actuator into the leg, and a structure for attaching the actuator must also be incorporated, making it difficult to mount the actuator on the leg.

[0005] The present disclosure has been made in consideration of these points, and its purpose is to provide a robot that can walk on all fours without providing a drive source in the legs for bending or extending the joints in the middle of the legs. [Means for solving the problem]

[0006] To achieve the above object, one aspect of the present disclosure may be directed to a quadruped robot capable of walking on four legs. The quadruped robot includes a main body, four legs connected to the main body so as to be rotatable relative to a connecting shaft and having joints at their intermediate portions, a first drive source provided on the main body and generating power for bending and extending the joints, a second drive source provided on the main body and generating power for rotating the legs about the connecting shafts, a first transmission unit that transmits the power of the first drive source to the joints, and a controller that controls the first drive source and the second drive source.

[0007] According to this configuration, the power generated by the first drive source is transmitted to the joints of the legs by the first transmission unit, thereby enabling the joints to bend and extend. Furthermore, the power generated by the second drive source enables the legs to rotate relative to the main body. By controlling the first drive source and the second drive source with a controller, a robot capable of walking on all fours can be obtained. Because the first drive source for moving the joints of the legs is provided on the main body, the legs do not require drive sources for moving the joints. This eliminates the need to route wiring from the main body to the legs, eliminates the need to provide space for incorporating drive sources in the legs, and also eliminates the need to provide a structure for attaching the drive sources to the legs.

[0008] The leg may have a base arm rotatably connected to the connecting shaft and a tip arm connected to the base arm. In this case, the joint may have a support shaft extending parallel to the connecting shaft and rotatably connecting a base end of the tip arm to a tip end of the base arm. The second driving source may be provided away from the connecting shaft in one direction of the front-rear direction of the main body, and may include a second transmission unit that generates a rotational force and transmits the rotational force of the second driving source to the base end of the base arm.

[0009] The joint portion may be provided at a base end of the tip-side arm and may include a tip-side tubular portion that rotates about the support shaft, and a plurality of first driven teeth that are circumferentially aligned on an outer circumferential surface of the tip-side tubular portion. In this case, the first drive source may rotate the connecting shaft, and the first transmission portion may include a first endless member that is wrapped around the tip-side tubular portion and the connecting shaft and engages with the first driven teeth and first drive teeth that are circumferentially aligned on the outer circumferential surface of the connecting shaft.

[0010] A base end of the base end arm may be provided with a base end tubular portion that rotates around the connecting shaft. In this case, a plurality of second driven teeth may be formed on an outer peripheral surface of the base end tubular portion so as to be aligned in the circumferential direction, a plurality of second drive teeth may be formed on an output shaft of the second drive source so as to be aligned in the circumferential direction, and the second transmission part may include a second endless member that is wrapped around the base end tubular portion and the output shaft and engages with the second driven teeth and the second drive teeth.

[0011] The first drive source and the second drive source may include a first motor and a second motor, respectively. The first drive source and the second drive source may be arranged side by side in the front-to-rear direction of the main body. Furthermore, the rotation axis of the first drive source and the axis of the connecting shaft may be arranged on the same straight line.

[0012] The first driving source and the second driving source may further include a first reducer that reduces the rotation speed of the first motor and a second reducer that reduces the rotation speed of the second motor, respectively. In this case, the first motor, the second motor, the first reducer, and the second reducer can be attached to a common member and formed into a unit. This allows the unit, whose legs can rotate and bend, to be made smaller. [Effects of the Invention]

[0013] As described above, it is possible to provide a robot that can walk on all fours without providing drive sources for bending the joints in the legs. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view of a four-legged walking robot according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of the left front leg unit as seen from the front left. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a diagram illustrating the movement of a four-legged robot when climbing up an obstacle. [Figure 5] FIG. 5 is a diagram illustrating the movement of a quadruped walking robot when it is turned upside down. [Figure 6] FIG. 6 is a diagram illustrating a state in which the legs of a quadruped walking robot are bent in the opposite direction. [Figure 7] FIG. 7 is a diagram illustrating the movement of a four-legged walking robot when going up and down stairs. [Figure 8] FIG. 8 is a diagram illustrating the difference in torque between the shoulder joint of the quadruped walking robot according to the embodiment of the present invention and a general shoulder joint. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

[0016] FIG. 1 shows a quadruped walking robot 1 according to an embodiment of the present invention. The quadruped walking robot 1 can be classified as a mammal-type robot and includes a main body 2, a left front leg 3, a right front leg 4, a left rear leg 5, and a right rear leg 6. The main body 2 is provided with a left front leg unit Y1 for driving the left front leg 3, a right front leg unit Y2 for driving the right front leg 4, a left rear leg unit Y3 for driving the left rear leg 5, and a right rear leg unit Y4 for driving the right rear leg 6. In the description of this embodiment, the direction of travel of the quadruped walking robot 1 corresponds to the forward / backward direction as shown in FIG. 1 , and the front and rear sides are defined, as well as the left and right sides. The quadruped walking robot 1 can move forward and backward by moving the left front leg 3, the right front leg 4, the left rear leg 5, and the right rear leg 6.

[0017] The main body 2 has a shape in which the dimension in the direction of travel is longer than the dimension in the left-right direction. The main body 2 is equipped with a secondary battery, a power supply circuit, etc. for supplying power to the left front leg unit Y1, the right front leg unit Y2, the left rear leg unit Y3, and the right rear leg unit Y4. Power may be supplied from an external source, in addition to being supplied from a secondary battery built into the main body 2.

[0018] A left front connecting shaft 21 is provided at the left front portion of the main body 2, and the left front leg 3 is connected to the left front connecting shaft 21 so as to be rotatable relative to it. A left rear connecting shaft 51 is provided at the left rear portion of the main body 2, and the left rear leg 5 is connected to the left rear connecting shaft 51 so as to be rotatable relative to it. A right front connecting shaft (not shown) is provided at the right front portion of the main body 2, and the right front leg 4 is connected to the right front connecting shaft so as to be rotatable relative to it. A right rear connecting shaft (not shown) is provided at the right rear portion of the main body 2, and the right rear leg 6 is connected to the right rear connecting shaft so as to be rotatable relative to it. Bendable and extensible joints 3A, 4A, 5A, 6A are provided at the intermediate portions of the left front leg 3, right front leg 4, left rear leg 5, and right rear leg 6, respectively. The left front leg 3, right front leg 4, left rear leg 5 and right rear leg 6 have at their tips ground contact parts 3B, 4B, 5B and 6B that come into contact with the ground or floor, for example.

[0019] The four-legged walking robot 1 can be made to stand by the left front leg 3, the right front leg 4, the left rear leg 5, and the right rear leg 6. The left front leg 3 can be moved by the left front leg unit Y1, the right front leg 4 can be moved by the right front leg unit Y2, the left rear leg 5 can be moved by the left rear leg unit Y3, and the right rear leg 6 can be moved by the right rear leg unit Y4. For example, the four-legged walking robot 1 can be made to walk by rotating the left front leg 3, right front leg 4, left rear leg 5, and right rear leg 6 about the left front connecting shaft 21, the right front connecting shaft, the left rear connecting shaft 51, and the right rear connecting shaft, respectively, and by bending and extending the joints 3A, 4A, 5A, and 6A.

[0020] The left front leg unit Y1, the right front leg unit Y2, the left rear leg unit Y3, and the right rear leg unit Y4 have the same structure. Specifically, the left front leg unit Y1 and the right front leg unit Y2 have a symmetrical structure, and the left rear leg unit Y3 and the right rear leg unit Y4 have a symmetrical structure. Furthermore, the left front leg unit Y1 and the left rear leg unit Y3 have a structure that is inverted in the front-to-rear direction, and the right front leg unit Y2 and the right rear leg unit Y4 have a structure that is inverted in the front-to-rear direction. The same is true for the left front leg 3, the right front leg 4, the left rear leg 5, and the right rear leg 6. Below, the structure of the left front leg unit Y1 and the structure of the left front leg 3 will be described in detail with reference to FIGS. 2 and 3.

[0021] 3, the left front leg unit Y1 includes a base member 22 that supports the left front connecting shaft 21, a base-end bearing member 23 that supports the base member 22 rotatably about an axis (hereinafter referred to as the first axis A1) that extends in the front-to-rear direction relative to the main body 2, a base-end motor 24 that rotates the base member 22 about the first axis A1, and a base-end reducer 25. The base-end bearing member 23, the base-end motor 24, and the base-end reducer 25 form a base-end joint section 3C.

[0022] As shown in Figure 3, the base member 22 is made of a highly rigid member that is long in the front-rear direction. A supported portion 22a having a circular cross section centered on the first axis A1 is provided at the rear end of the base member 22. The supported portion 22a is inserted into an insertion hole 2a formed in the main body 2. The insertion hole 2a has a circular shape centered on the first axis A1. The base-end bearing member 23 is disposed between the outer peripheral surface of the supported portion 22a and the inner peripheral surface of the insertion hole 2a, and is made up of, for example, a cross roller bearing.

[0023] The base-side motor 24 is disposed rearward and spaced apart from the supported portion 22a of the base member 22. A main body portion 24a of the base-side motor 24 is fixed to the main body 2. Meanwhile, a motor shaft 24b of the base-side motor 24 protrudes forward from the main body portion 24a and is disposed coaxially with the first axis A1. The base-side reducer 25 is disposed between the supported portion 22a of the base member 22 and the main body portion 24a of the base-side motor 24, and reduces the rotational speed of the base-side motor 24 before transmitting it to the base member 22. The motor shaft 24b of the base-side motor 24 is connected to the input side of the base-side reducer 25. The supported portion 22a of the base member 22 is connected to the output side of the base-side reducer 25. Therefore, the rotation speed of the base-end motor 24 is reduced by the base-end reducer 25 and then input to the supported portion 22a of the base member 22, causing the base member 22 to rotate around the first axis A1. The base-end reducer 25 may have any configuration, and may be, for example, a trochoid reducer.

[0024] The left front connecting shaft 21 is supported on a portion of the base member 22 that is forward of the center in the front-rear direction. That is, a front bearing hole 22b is formed in the front portion of the base member 22, penetrating in the left-right direction (a direction perpendicular to the first axis A1). The front bearing hole 22b supports the left front connecting shaft 21 so that it can rotate about the second axis A2, and has a circular shape centered on the second axis A2. The second axis A2 is an axis that is perpendicular to the first axis A1 and extends in the left-right direction. Note that because the base member 22 rotates about the first axis A1, the rotation of the base member 22 causes the second axis A2 to change from extending horizontally as viewed from the front to being inclined.

[0025] The left front connecting shaft 21 is arranged coaxially with the second shaft A2. A base end portion of the left front connecting shaft 21 is inserted into the front bearing hole 22b. The left front leg unit Y1 has a front bearing member 26. The front bearing member 26 is disposed between the outer peripheral surface of the base end portion of the left front connecting shaft 21 and the inner peripheral surface of the front bearing hole 22b. The front bearing member 26 is formed, for example, by a cross roller bearing or the like.

[0026] The left front leg unit Y1 has a front motor (first motor) 27 and a front reducer (first reducer) 28 for driving the left front connecting shaft 21. The front motor 27 and the front reducer 28 constitute a first drive source D1 that is provided on the main body 2 and generates power for bending and extending the joint 3A. The rotation axis of the first drive source D1 and the axis of the left front connecting shaft 21 are arranged on the same straight line (second axis A2), and the first drive source D1 rotates the left front connecting shaft 21.

[0027] The main body 27a of the front motor 27 is fixed to the front portion of the base member 22. The motor shaft 27b of the front motor 27 protrudes leftward from the main body 27a and is arranged coaxially with the second axis A2. The front reducer 28 is disposed between the main body 27a of the front motor 27 and the left front connecting shaft 21 and reduces the rotational speed of the front motor 27 before transmitting it to the left front connecting shaft 21. The motor shaft 27b of the front motor 27 is connected to the input side of the front reducer 28. The left front connecting shaft 21 is connected to the output side of the front reducer 28. Therefore, the rotational speed of the front motor 27 is reduced by the front reducer 28 and then input to the left front connecting shaft 21, causing the left front connecting shaft 21 to rotate about the second axis A2. The front reducer 28 may have any configuration, and may be, for example, a trochoid reducer.

[0028] The left front leg unit Y1 has a rotating shaft 29, and a rear motor (second motor) 30 and a rear reducer (second reducer) 31 for driving the rotating shaft 29. In this embodiment, the rear motor 30, the rear reducer 31, the front motor 27, and the front reducer 28 are attached to a common member, the base member 22, and formed into a unit. This allows the left front leg unit Y1, which allows the left front leg 3 to rotate and bend, to be made smaller.

[0029] The rotating shaft 29 is supported on a portion of the base member 22 that is rearward of the center in the front-to-rear direction. The rotating shaft 29, the rear motor 30, and the rear reducer 31 constitute a second driving source D2 that is provided on the main body 2 and generates power to rotate the left front leg 3 about the left front connecting shaft 21. The output shaft of the second driving source D2 is constituted by the rotating shaft 29.

[0030] That is, the second driving source D2 is provided at a distance from the left front connecting shaft 21 to the rear side of the main body 2 and generates a rotational force. In this way, the first driving source D1 is provided at the front side and the second driving source D2 is provided at the rear side, so that the first driving source D1 and the second driving source D2 are aligned in the front-to-rear direction of the main body 2. By aligning the first driving source D1 and the second driving source D2 in the front-to-rear direction, the left-to-right dimension of the left front leg unit Y1 can be shortened.

[0031] A rear bearing hole 22c is formed in the rear portion of the base member 22, penetrating in a direction parallel to the second axis A2. The rear bearing hole 22c is for supporting the rotation shaft 29 so that it can rotate about the third axis A3, and is shaped like a circle centered on the third axis A3. The left front leg unit Y1 has a rear bearing member 32. The rear bearing member 32 is disposed between the outer peripheral surface of the base end portion of the rotation shaft 29 and the inner peripheral surface of the rear bearing hole 22c. The rear bearing member 32 is formed, for example, by a cross roller bearing or the like.

[0032] The main body portion 30a of the rear motor 30 is fixed to a portion of the base member 22 rearward of the center portion in the front-rear direction. The motor shaft 30b of the rear motor 30 protrudes leftward from the main body portion 30a and is disposed rearward of and parallel to the second axis A2. The rear reducer 31 is disposed between the main body portion 30a of the rear motor 30 and the rotating shaft 29, and reduces the rotational speed of the rear motor 30 before transmitting it to the rotating shaft 29. The motor shaft 30b of the rear motor 30 is connected to the input side of the rear reducer 31. The rotating shaft 29 is connected to the output side of the rear reducer 31. Therefore, the rotational speed of the rear motor 30 is reduced by the rear reducer 31 before being input to the rotating shaft 29, and the rotating shaft 29 rotates around the third axis A3 parallel to the second axis A2. The rear reducer 31 may have any configuration, but may be, for example, a trochoid reducer.

[0033] The left front leg 3 has a base arm 35 rotatably connected to the left front connecting shaft 21, and a tip arm 36 connected to the base arm 35 via a joint 3A. A cylindrical base tube portion 35a into which an intermediate portion of the left front connecting shaft 21 is inserted and a circular base insertion hole 35b into which a tip portion of the left front connecting shaft 21 is inserted are coaxially formed at the base end of the base arm 35. The base tube portion 35a is fixed to the main body of the base arm 35 and is integrated with the main body of the base arm 35.

[0034] The base-end tubular portion 35a and the base-end insertion hole 35b are arranged coaxially with the second axis A2. A base-end bearing member 37, such as a ball bearing, is arranged between the inner peripheral surfaces of the base-end tubular portion 35a and the base-end insertion hole 35b and the outer peripheral surface of the left front connecting shaft 21. This allows the base-end arm 35, including the base-end tubular portion 35a, to rotate around the left front connecting shaft 21 relative to the left front connecting shaft 21. The left front connecting shaft 21 forms a shoulder joint of the quadruped walking robot 1.

[0035] A plurality of base-end driven teeth (second driven teeth) 35c are formed on the outer peripheral surface of the base-end side tubular portion 35a so as to be aligned in the circumferential direction. Meanwhile, the tip end of the rotary shaft 29 has a drive pulley 29a. A plurality of base-end drive teeth (second drive teeth) 29b are formed on the outer peripheral surface of the drive pulley 29a so as to be aligned in the circumferential direction.

[0036] As shown by the dashed line in FIG. 3 , a base-side timing belt 38 is wound around the base-side tubular portion 35a and the drive pulley 29a of the rotary shaft 29. The base-side timing belt 38 is annular (endless). The inner surface of the base-side timing belt 38 is provided with a concave-convex shape that engages with the base-side driven teeth 35c and the base-side drive teeth 29b. The engagement of this concave-convex shape with the base-side driven teeth 35c and the base-side drive teeth 29b transmits the rotational force of the drive pulley 29a of the rotary shaft 29 to the base-side tubular portion 35a via the base-side timing belt 38. The base-side timing belt 38 is a member that transmits the rotational force of the second drive source D2 to the base end of the base-side arm 35 and is an example of a second endless member (endless belt) of the present invention. The base-side timing belt 38 constitutes a second transmission unit. In addition, the base end side timing belt 38 is omitted in FIG.

[0037] The joint 3A of the left front leg 3 has a support shaft 40 that rotatably connects the base end of the tip end arm 36 to the tip end of the base end arm 35, a tip end cylinder portion 41, and a tip end driven tooth (first driven tooth) 42. The support shaft 40 can be formed, for example, from a cylindrical pin, and extends in the direction of the fourth axis A4 that is parallel to the left front connecting shaft 21, with both axial ends thereof inserted into holes 35d formed in the tip end of the base end arm 35 and held by the base end arm 35.

[0038] The tip-side tubular portion 41 is composed of a cylindrical member provided at the base end of the tip-side arm 36. The tip-side tubular portion 41 is fixed to the base end of the tip-side arm 36 and is integrated with the tip-side arm 36. An axially intermediate portion of the support shaft 40 is inserted into the tip-side tubular portion 41. A tip-side bearing member 43, such as a ball bearing, is disposed between the outer circumferential surface of the support shaft 40 and the inner circumferential surface of the tip-side tubular portion 41. This allows the tip-side arm 36 to rotate relative to and around the support shaft 40. In addition, a plurality of tip-side driven teeth 42 are formed on the outer circumferential surface of the tip-side tubular portion 41 so as to be aligned in the circumferential direction.

[0039] Tip drive teeth (first drive teeth) 21a are formed on the outer peripheral surface of the tip end portion of the left front connecting shaft 21 so as to be aligned in the circumferential direction. As shown by the dashed line in FIG. 3 , a tip timing belt 44 is wound around the tip end cylinder portion 41 and the tip end portion of the left front connecting shaft 21. The tip timing belt 44 is annular (endless) like the base end timing belt 38. The tip timing belt 44 has an inner surface provided with a concave-convex shape that engages with the tip end driven teeth 42 and the tip end drive teeth 21a. The engagement of this concave-convex shape with the tip end driven teeth 42 and the tip end drive teeth 21a transmits the rotational force of the left front connecting shaft 21 to the tip end cylinder portion 41 via the tip timing belt 44. The tip timing belt 44 is an example of a first endless belt (endless member) of the present invention. It is a first transmission unit that transmits the power of the first drive source D1 to the joint portion 3A. In FIG. 2, the leading end side timing belt 44 is omitted.

[0040] The quadruped walking robot 1 includes a controller 60 (shown only in FIG. 3) that controls the base-end motor 24, the front motor 27 of the first drive source D1, and the rear motor 30 of the second drive source D2. The controller 60 is configured, for example, by a microcomputer having one or more central processing units, ROM, RAM, etc., or a storage device, and operates according to a predetermined program to individually control the base-end motor 24, the front motor 27, and the rear motor 30. The quadruped walking robot 1 may also include a communication module (not shown). Examples of the communication module include a device connected to a local area network and a device capable of short-range wireless communication. In the case of short-range wireless communication, a device conforming to standards such as Bluetooth (registered trademark) can be used. The communication module may also be configured by a device capable of wired communication.

[0041] When the communication module receives a control signal from the outside, the controller 60 controls the base end motor 24, the front motor 27, and the rear motor 30 based on the control signal. Note that the right front leg unit Y2, the left rear leg unit Y3, and the right rear leg unit Y4 are similarly controlled by the controller 60. The left front leg unit Y1, the right front leg unit Y2, the left rear leg unit Y3, and the right rear leg unit Y4 are controlled in a coordinated manner by the controller 60, thereby enabling the quadruped walking robot 1 to walk.

[0042] When the controller 60 controls the base end motor 24 to rotate the base member 22 in the direction of arrow 100, the left front leg 3 moves leftward. Conversely, when the controller 60 controls the base end motor 24 to rotate the base member 22 in the direction of arrow 101, the left front leg 3 moves rightward.

[0043] When the controller 60 controls the rear motor 30 to rotate the rotary shaft 29 in the direction of arrow 102, the rotational force of the rotary shaft 29 is transmitted to the base-side cylinder portion 35a of the base-side arm 35 via the base-side timing belt 38, and acts as a force to rotate the base-side cylinder portion 35a in the direction of arrow 104. Because the base-side cylinder portion 35a is integrated with the base-side arm 35, the rear motor 30 can rotate the base-side arm 35 in the direction of arrow 104. This causes the left front leg 3 to rotate in the direction of arrow 104 around the left front connecting shaft 21.

[0044] Conversely, when the controller 60 controls the rear motor 30 to rotate the rotary shaft 29 in the direction of arrow 103, the rotational force of the rotary shaft 29 is transmitted to the base-end cylinder portion 35a of the base-end arm 35 via the base-end timing belt 38, and acts as a force to rotate the base-end cylinder portion 35a in the direction of arrow 105, causing the left front leg 3 to rotate around the left front connecting shaft 21 in the direction of arrow 105. In other words, by the controller 60 controlling the rear motor 30, the entire left front leg 3 can be rotated in the front-to-back and up-and-down directions, thereby swinging and rotating the left front leg 3.

[0045] Furthermore, since the front motor 27 and the rear motor 30 are provided on the main body 2 and the left front leg 3 is not provided with the front motor 27 or the rear motor 30, the left front leg 3 does not require a drive source for moving the joint 3A. This eliminates the need to route wiring from the main body 2 to the left front leg 3, eliminates the need to provide space for a built-in drive source in the left front leg 3, and also eliminates the need to provide a structure for attaching a drive source in the left front leg 3. Because wiring to the left front leg 3 is no longer required, the left front leg 3 can rotate 360° or more around the left front connecting shaft 21. Furthermore, since the left front leg 3 does not have a built-in drive source, the left front leg 3 can be made lighter and smaller.

[0046] Furthermore, when the controller 60 controls the front motor 27 to rotate the left front connecting shaft 21 in the direction of arrow 104, the rotational force of the left front connecting shaft 21 is transmitted to the tip side cylinder portion 41 of the tip side arm 36 via the tip side timing belt 44, and acts as a force to rotate the tip side cylinder portion 41 in the direction of arrow 106. Because the tip side cylinder portion 41 is integrated with the tip side arm 36, for example, it is possible to rotate the tip side arm 36 in the direction of arrow 106 while keeping the base side arm 35 stationary. It is also possible to rotate the tip side arm 36 in the direction of arrow 106 while rotating the base side arm 35 by the rear side motor 30. This causes the tip side arm 36 to swing or rotate in the direction of arrow 106 around the support shaft 40.

[0047] Conversely, when the controller 60 controls the front motor 27 to rotate the left front connecting shaft 21 in the direction of arrow 105, the rotational force of the left front connecting shaft 21 is transmitted to the tip-side tubular portion 41 of the tip-side arm 36 via the tip-side timing belt 44, and acts as a force to rotate the tip-side tubular portion 41 in the direction of arrow 107. Because the tip-side tubular portion 41 is integrated with the tip-side arm 36, for example, the tip-side arm 36 can be rotated in the direction of arrow 107 while the base-side arm 35 is stationary. It is also possible to rotate the tip-side arm 36 in the direction of arrow 107 while rotating the base-side arm 35 by the rear motor 30. This causes the tip-side arm 36 to swing or rotate around the support shaft 40 in the direction of arrow 107. In other words, the joint 3A of the left front leg 3 can be flexed and extended.

[0048] The controller 60 controls the front motors 27 and rear motors 30 of the left front leg unit Y1, right front leg unit Y2, left rear leg unit Y3, and right rear leg unit Y4 to rotate the left front leg 3, right front leg 4, left rear leg 5, and right rear leg 6, and to flex and extend the joints 3A, 4A, 5A, and 6A, thereby enabling the quadruped walking robot 1 to walk. The walking algorithm of the quadruped walking robot 1 can be a walking algorithm of a mammalian robot, but the quadruped walking robot 1 of this embodiment has unique movements. The movements unique to the quadruped walking robot 1 of this embodiment will be described in detail below.

[0049] FIG. 4 is a diagram illustrating the movement of the quadruped walking robot 1 when climbing up an obstacle 200. The obstacle 200 may be, for example, a staircase or a step stool. As shown in FIG. 4, when the quadruped walking robot 1 walks up to the front of the obstacle 200 and approaches it, as shown by numbers 1 to 3, the left front leg 3 rotates from rear to front around the left front connecting shaft 21, and the joint 3A is bent and then extended forward, placing the ground contact part 3B on the upper surface of the obstacle 200. In this way, the quadruped walking robot 1 can climb up the obstacle 200.

[0050] This movement to climb the obstacle 200 may be initiated by a visual sensor or the like (not shown) mounted on the quadruped walking robot 1 when the distance from the obstacle 200 becomes equal to or less than a predetermined distance, or may be initiated based on an instruction from an operator operating the quadruped walking robot 1. An example of the visual sensor is a camera. A distance sensor may be mounted instead of or in addition to the visual sensor.

[0051] The four-legged walking robot 1 may also be configured to be remotely controllable. For example, the four-legged walking robot 1 can be controlled by operating a control device (not shown) at a location remote from the four-legged walking robot 1 and transmitting the control signal to the four-legged walking robot 1. The control device may be a dedicated device, or a general-purpose device such as a smartphone or tablet terminal can be used as a control device by installing an application thereon. Furthermore, by setting the destination and waypoints of the four-legged walking robot 1 in advance, the four-legged walking robot 1 can be automatically moved to the destination and waypoints.

[0052] FIG. 5 shows the quadruped walking robot 1 with the main body 2 turned upside down. The black square 201 in FIG. 5 indicates the upper side of the main body 2. In the right-hand view of FIG. 5, the square 201 is located above the main body 2, whereas in the left-hand view of FIG. 5, the square 201 is located below the main body 2, resulting in the main body 2 being turned upside down. When the main body 2 is turned upside down, the left front leg 3 and the left rear leg 5 are rotated 180° around the left front connecting shaft 21 and the left rear connecting shaft 51, respectively. Similarly, the right front leg 4 and the right rear leg 6 are also rotated. This allows the quadruped walking robot 1 to assume a standing posture while the main body 2 remains turned upside down. Similarly, when changing from the state shown in the left-hand view of FIG. 5 to the state shown in the right-hand view of FIG. 5, the left front leg 3, the right front leg 4, the left rear leg 5, and the right rear leg 6 are rotated 180°.

[0053] As shown in FIG. 6 , the joints 3A, 4A, 5A, and 6A of the left front leg 3, the right front leg 4, the left rear leg 5, and the right rear leg 6 can be bent to be convex forward or convex backward. As a result, as shown in FIG. 7 , for example, when the quadruped walking robot 1 ascends and descends stairs, interference with the stairs can be avoided by bending the joints 3A, 4A, 5A, and 6A to be convex forward. Note that, as shown by the imaginary lines, if the joints are bent to be convex backward, the left front leg 3, the right front leg 4, the left rear leg 5, and the right rear leg 6 will interfere with the stairs. Therefore, the quadruped walking robot 1 of this embodiment can ascend stairs in a forward-moving position and then descend stairs in the same forward-moving position.

[0054] The upper diagram in FIG. 8 is a diagram explaining the movement of a general shoulder joint, and the lower diagram is a diagram explaining the movement of the shoulder joint of the quadruped walking robot 1 according to an embodiment of the present invention. When obtaining a horizontal thrust, in a general mammal-type mechanism, the torque of the shoulder joint is proportional to the distance L from the shoulder to the tip of the leg. On the other hand, in the quadruped walking robot 1 according to an embodiment of the present invention, even when obtaining the same horizontal thrust, the torque required for the shoulder joint is proportional to the distance l from the shoulder (left front connecting shaft 21) to the knee (support shaft 40). Therefore, the quadruped walking robot 1 according to an embodiment of the present invention can obtain the same thrust with a smaller torque than a robot equipped with a general shoulder joint.

[0055] The above-described embodiment is merely illustrative in all respects and should not be construed as limiting. Furthermore, all modifications and variations within the scope of the claims are within the scope of the present invention. For example, endless members such as roller chains may be used instead of the base end timing belt 38 and the tip end timing belt 44. In this case, a configuration may be provided with sprockets around which the roller chains are wound. [Industrial Applicability]

[0056] As described above, the four-legged walking robot according to the present disclosure can be used, for example, to perform various tasks in place of humans. [Explanation of symbols]

[0057] 1. Four-legged robot 2 Main unit 3 Front left leg 4 Right front leg 5 Left rear leg 6 Right rear leg 3A Joints 27 Front motor (first motor) 28 Front reducer (1st reducer) 30 Rear motor (second motor) 31 Rear reducer (2nd reducer) 38 Base end timing belt (second endless member, second transmission part) 44 Tip side timing belt (first endless member, first transmission part) 60 Controller D1 First drive source D2 Second drive source

Claims

1. A quadruped walking robot, The main body and four legs connected to the connecting shaft of the main body so as to be rotatable relative to each other and having joints at their intermediate portions; a first drive source provided in the main body and generating power for bending and extending the joint portion; a second drive source provided on the main body and generating power to rotate the leg portion around the connecting shaft; a first transmission unit that transmits power from the first drive source to the joint unit; a controller that controls the first drive source and the second drive source.

2. 2. The quadruped walking robot according to claim 1, The leg portion has a base end arm and a tip end arm rotatably connected to the connecting shaft, the joint portion has a support shaft that extends parallel to the connecting shaft and rotatably connects a base end portion of the tip end arm to a tip end portion of the base end arm, the second drive source is provided away from the connecting shaft in one direction of the front-rear direction of the main body, and generates a rotational force; a second transmission unit that transmits the rotational force of the second drive source to the base end of the base end arm.

3. 3. The quadruped walking robot according to claim 2, the joint portion is provided at a base end of the tip-side arm and includes a tip-side tubular portion that rotates around the support shaft, and a plurality of first driven teeth that are formed on an outer circumferential surface of the tip-side tubular portion and are aligned in a circumferential direction, The first drive source rotates the connecting shaft, the first transmission part has a first endless member that is wound around the tip side tubular part and the connecting shaft and engages with the first driven teeth and first drive teeth that are formed on the outer peripheral surface of the connecting shaft so as to be aligned in the circumferential direction.

4. 4. The quadruped walking robot according to claim 3, a base end of the base end arm is provided with a base end cylinder portion that rotates around the connecting shaft; a plurality of second driven teeth are formed on an outer peripheral surface of the base end side cylindrical portion so as to be aligned in a circumferential direction; a plurality of second drive teeth are formed on the output shaft of the second drive source so as to be aligned in a circumferential direction; the second transmission part has a second endless member that is wound around the base end side tubular part and the output shaft and engages with the second driven teeth and the second drive teeth.

5. 5. The quadruped walking robot according to claim 4, the first driving source and the second driving source include a first motor and a second motor, respectively; The quadruped walking robot, wherein the first driving source and the second driving source are aligned in a front-to-rear direction of the main body.

6. 6. The quadruped walking robot according to claim 5, a rotation axis of the first drive source and an axis of the connecting shaft are arranged on the same straight line.

7. 6. The quadruped walking robot according to claim 5, the first driving source and the second driving source further include a first reducer that reduces the rotation speed of the first motor and a second reducer that reduces the rotation speed of the second motor, respectively; the first motor, the second motor, the first reducer, and the second reducer are attached to a common member and unitized.

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