JP7190689B2 - JOINT STRUCTURE AND JOINT DRIVING DEVICE, AND BIPED ROBOT - Google Patents

Description

TECHNICAL FIELD The present invention relates to a joint structure, a joint driving device, and a bipedal robot that allow relative rotation in intersecting directions of rotation.

A joint structure is known that allows two parts connected via a joint to rotate relative to each other around the joint. As this type of joint structure, various types of joint structures have been developed, such as the ankles of a bipedal walking robot, in which the legs are connected to the lower leg so as to be relatively rotatable in the pitch and roll directions.

In recent years, bipedal robots have been required to walk not only on flat ground but also on rough terrain with unevenness and steep slopes, stably keeping the soles of the feet in contact with the ground and walking with high reliability. For this reason, as a bipedal walking robot, the height of the ankle is lowered, the range of motion around the joint is widened, and interference from the surrounding environment is eliminated. A structure is preferred.

For this reason, Patent Document 1 discloses a walking robot having a pitch axis and a roll axis that are orthogonal to each other at the ankle. In the ankle joint structure of this walking robot, strain wave gearing is arranged on each of the pitch axis and the roll axis, a first motor for inputting driving force to the strain wave gearing on the pitch axis is arranged on the lower leg, and , a second motor is arranged on the roll shaft together with a strain wave gearing.

However, in the joint structure described in Patent Document 1, since the strain wave gearing of the pitch axis is arranged on the side surface of the lower leg, the movable range around the roll axis is narrowed, and furthermore, the joint structure contacts the floor surface. It has a structure that is easy to interfere with. Attempting to avoid these places restrictions on the layout of parts around the ankle, and the ankle is separated from the floor, resulting in an increase in height.

Further, Patent Literature 2 discloses a walking robot having orthogonal pitch and roll axes at the ankles. In the ankle joint structure of this walking robot, an actuator and a link member are arranged on both sides of the roll axis, and a spherical bearing is provided between the links. By arranging a link member and controlling the rotation angles of the three actuators, both rotation in the pitch direction and rotation in the roll direction are realized.

However, in the joint structure described in Patent Document 2, the driving force of the actuator is transmitted through the link member to rotate the foot side around the ankle, and the link mechanism uses a spherical bearing to move three-dimensionally. Since it is used, it is difficult to ensure a large movable range of the ankle joint, and control processing becomes complicated because the actuators cannot be driven independently.

JP-A-3-184782 JP 2013-248699 A

Therefore, according to the present invention, it goes without saying that the movable range in one direction is widened, and even when two intersecting rotational directions are combined (movable in the pitch direction and also movable in the roll direction), movement in both directions is possible. It is an object of the present invention to secure a wide range, realize a compact joint structure with a low ankle height, and provide a joint driving device and a bipedal walking robot equipped with the joint structure.

A first aspect of the joint structure invention for solving the above problems is a first strain wave gear device composed of various elements that relatively rotate about a first joint axis, and various elements that relatively rotate about a second joint axis. and a second strain wave gearing composed of elements and mounted on a main unit, wherein the first strain wave gearing receives a rotational driving force around the first joint shaft from a first motor. the second strain wave gearing includes an input element to which a rotational driving force about the second joint shaft is transmitted and input from a second motor, the first strain wave gearing and the second strain wave gearing In the strain wave gearing, the first joint shaft and the second joint shaft are positioned on the same plane or within a range smaller than the vertical thickness of the first strain wave gearing or the second strain wave gearing. The first strain wave gearing and the second strain wave gearing are characterized in that the fixed element is connected to the relatively immovable member and the output element is connected to the relative drive member. It is.

In the first aspect of the joint structure invention, the first strain wave gearing and the second strain wave gearing are arranged such that the first joint shaft and the second joint shaft are in the same plane or within a range less than the thickness of these gear devices. Since they are arranged to cross each other inside, it is possible to reduce the structure around the axis as much as possible to make it compact, and they can be deeply rotated relative to each other, and the height of the ankle can be suppressed and mounted on the main unit. .

A second aspect of the joint structure invention for solving the above problems is, in addition to the above first aspect, one of the first strain wave gearing and the second strain wave gearing has the other first joint shaft. Alternatively, it is arranged on the axis line of the second joint shaft, or at a position close to the other of the first joint shaft or the second joint shaft.

In the second aspect of the joint structure invention, one of the first strain wave gearing and the second strain wave gearing is arranged on the axis line of the other first joint shaft or the second joint shaft or in a position close to the other. It can be rotated around the other axis, and a compact rotating structure can be realized without having to prepare an unnecessarily large space for the rotation. One of the first strain wave gearing and the second strain wave gearing realizes an overall compact rotation structure by laying out necessary parts around the axis of the other and arranging the other on the outer peripheral side. It is possible and preferable.

A third aspect of the joint structure invention for solving the above problems is, in addition to the above-described first or second aspect, the first strain wave gearing and the second strain wave gearing as the input element. It comprises a generator, a flexible external gear as said fixed element and a rigid internal gear as said output element.

In the third aspect of the joint structure invention, the joint shaft is a common axis, and the wave generator as the input element, the flexible external gear as the fixed element, and the rigid internal gear as the output element are used as axes. By arranging them sequentially from the central side, interference between the relatively rotating member rotating around the joint axis and the strain wave gearing becomes less likely to occur, and relative rotation is ensured while ensuring a wider joint movable range around the joint axis. It is possible to keep the distance required for connection with the member small.

A fourth aspect of the joint structure invention for solving the above problems is, in addition to any one of the first to third aspects, one or both of the first motor and the second motor One characterized by having a rotary drive shaft parallel to one joint shaft or the second joint shaft, and transmitting and inputting a rotary drive force to the input element of the first wave gear device or the second wave gear device. is.

In the fourth aspect of the joint structure invention, in one or both of the first strain wave gearing and the second strain wave gearing, the input element and the rotational drive shaft are made parallel to each other so that their radial directions are common. can be arranged compactly.

A fifth aspect of the joint structure invention for solving the above problems is, in addition to any one of the first to fourth aspects, wherein the first motor and the second motor are arranged on the relatively immovable member. It is characterized by being

In the fifth aspect of the joint structure invention, a motor can be arranged and driven on the relatively immovable member, and the structures around the first and second joint shafts can be made compact and relatively rotated. .

A sixth aspect of the joint structure invention for solving the above problems includes, in addition to any one of the first to fifth aspects, the relatively stationary member and the relatively driving member as constituent elements, and the relative A first wiring passage hole formed in a path through which the first joint shaft passes so as to communicate the inside and the outside of the stationary member, and a path through which the second joint shaft passes so as to communicate the inside and the outside of the relative driving member. and a communicating wiring passage hole formed in an intervening member so as to communicate the first wiring passage hole and the second wiring passage hole. It is something to do.

In the joint structure according to the sixth aspect of the invention, the wiring that needs to be connected to the internal structure can pass through the first joint shaft and the second joint shaft and be pulled out to the outside of the relatively stationary member and the relatively driving member, It is possible to suppress the rotational load applied to the wiring by rotating it around the joint axis as much as possible, and to make it difficult to cause damage due to contact with the surroundings.

A seventh aspect of the joint structure invention for solving the above problems includes, in addition to any one of the first to sixth aspects, the relatively stationary member and the relatively driving member as constituent elements, a cover covering all or part of components that rotate relative to each other with the relative driving member about one joint axis, the cover having a curved surface about the first joint axis, The relatively immovable member is characterized in that it has a similar concave shape that closely faces the curved surface of the cover.

In the joint structure according to the seventh aspect of the invention, it is possible to rotate the relatively immovable member relative to the relative driving member while avoiding catching a foreign object around the first joint shaft.

A first aspect of the invention of a joint driving device for solving the above problems is a joint driving device comprising any one of the first to seventh aspects of the above joint structure invention, wherein the first motor; the second motor; a first drive rotation angle sensor for detecting a drive rotation angle of a rotary drive shaft of the first motor; and a second drive rotation angle sensor for detecting a drive rotation angle of the rotary drive shaft of the second motor. a first relative rotation angle sensor for detecting a relative rotation angle between the fixed element and the output element of the first strain wave gearing; and a relative rotation angle between the output element and the fixed element of the second strain wave gearing. and a second relative rotation angle sensor for transmitting rotational driving force from the rotary drive shaft of the first motor to the input element of the first strain wave gearing according to the detection value of the first drive rotation angle sensor. A first subtraction value is calculated by subtracting the detection value of the first relative rotation angle sensor from an integrated value obtained by integrating the ratio and the speed reduction ratio from the input element to the output element of the first strain wave gearing, and the second driving is performed. According to the detection value of the rotation angle sensor, the speed reduction ratio for transmitting the rotational driving force from the rotary drive shaft of the second motor to the input element of the second wave gear device and the transmission rate from the input element to the output element of the second wave gear device. A second subtraction value is calculated by subtracting the detection value of the second relative rotation angle sensor from an integrated value obtained by integrating the speed reduction ratio and one of the first subtraction value and the second subtraction value, or the first subtraction value. The apparatus is characterized by comprising detection means for detecting abnormality of the joint structure based on both the subtraction value and the second subtraction value.

In the first aspect of the invention of this joint driving device, it is possible to detect the occurrence of an abnormality in the constituent members, for example, the loosening of the screw fastening or the ratcheting in the strain wave gear device, from the first and second subtraction values. become.

A first aspect of the invention of a bipedal walking robot for solving the above-mentioned problems is any one of the first to seventh aspects of the above-described joint structure invention, and pitching at the ankle connecting the lower leg and the foot is performed. It is provided as an ankle joint that performs motion and rolling motion.

In the first aspect of the bipedal walking robot invention, any one of the first to seventh aspects of the above joint structure invention can be provided as an ankle joint. The feet can be deeply rotated relative to each other.

A second aspect of the invention of a bipedal walking robot for solving the above-mentioned problems comprises the first aspect of the above-described joint drive device invention.

This second aspect of the bipedal walking robot invention can include the first aspect of the above-described joint drive device invention. It becomes possible to detect the occurrence of abnormalities such as

Thus, according to one aspect of the present invention, the joint axes of the first strain wave gearing and the second strain wave gearing intersect in a close range such as in the same plane to form a compact structure. These first strain wave gearing and second strain wave gearing transmit the rotational driving force of the first motor and the second motor of the rotary drive shaft parallel to the joint shaft to their respective input elements. can be provided with a simple structure, and can be easily driven and controlled separately.

Therefore, it is possible to realize a joint structure that can be arranged at a low position while improving the degree of freedom in layout around the joint with a compact structure that has a wide movable range and does not require a high height.

As a result, for example, the joint structure including the first strain wave gearing and the second strain wave gearing is placed at a low position as the ankle of the biped robot (main device), and the fixed element is connected using the lower leg as a relatively immovable member. At the same time, by connecting the output elements using the feet as the relative driving members, it is possible to comfortably walk even on rough terrain with unevenness.

FIG. 1 is a diagram showing an example of a bipedal walking robot equipped with a joint structure and a joint driving device according to an embodiment of the present invention, and is a perspective view showing the appearance thereof. FIG. 2 is a side view showing the ankle. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2, showing the internal structure of the ankle. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2, showing the internal structure of the ankle. FIG. 5 is a perspective view of essential parts for explaining the power source of the ankle joint. FIG. 6 is a perspective view of essential parts for explaining the power source of the ankle joint and the rotation mechanism in the roll direction. FIG. 7 is a side view showing a rotation state of the foot with respect to the lower leg by the ankle joint in the pitch direction. FIG. 8 is a side view showing a state of rotation of the foot with respect to the lower leg by the ankle joint in the reverse pitch direction of FIG. FIG. 9 is a side view showing the rotation of the foot relative to the lower leg by the ankle joint in the roll direction. FIG. 10 is a side view showing a state of rotation of the foot relative to the lower leg by the ankle joint in the reverse roll direction of FIG. FIG. 11 is a side view showing the rotation state of the foot relative to the lower leg by the ankle joint in the same pitch direction as in FIG. 7 and in the same roll direction as in FIG. 10 (reverse roll direction in FIG. 9). FIG. 12 is a side view showing the rotation of the foot relative to the lower leg by the ankle joint in the same pitch direction as in FIG. 8 (reverse pitch direction in FIG. 7) and in the same roll direction as in FIG. FIG. 13 is a front view showing the attached state of the ankle joint cover. FIG. 14 is a rear view showing the attached state of the ankle joint cover. FIG. 15 is a side view showing the attached state of the ankle joint cover. FIG. 16 is a partially omitted side view showing the positional relationship of the ankle joint cover within the lower leg. FIG. 17 is a conceptual configuration diagram for explaining a control unit that controls driving of the ankle joint.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 17 are diagrams showing an example of a biped walking robot equipped with a joint structure and a joint driving device according to an embodiment of the present invention.

In FIG. 1, the biped robot 10 has a symmetrical structure including a waist 11, left and right legs 12, left and right legs 15, a chest 16, left and right arms 17, and a head 18. Built in human form. The leg portion 12 is divided into a thigh portion 13 and a lower leg portion 14. The thigh portion 13 is connected to the waist portion 11 via a hip joint 21, and the lower leg portion 14 is connected to the thigh portion 13 at a knee joint. 22 , and a leg 15 is connected to the lower leg 14 via an ankle joint 23 . Here, since the bipedal robot 10 is constructed to have a left-right symmetrical structure, the right side structure of the present embodiment will be illustrated, and the description will be made without distinguishing between left and right. The inside of the portion 14 will be described.

As shown in FIG. 2, the bipedal robot (main unit) 10 has a pitch axis 24s shown in FIG. 3 and a roll axis shown in FIG. Ankle joints 23 are arranged which are relatively rotatably connected with each of the axes 25s as a rotation axis. The ankle joint 23 has a pitch joint structure 41 and a roll joint structure 61 and is connected to the lower leg 14 and the foot 15 so as to be relatively rotatable. Here, in the pitch joint structure 41 and the roll joint structure 61, a motor, which will be described later, is installed as a power source for relatively rotating the leg portion 15 in the pitch direction and the roll direction with respect to the lower leg portion 14, and the fixed side is not relatively rotatable. is called a fixed member, and the relatively rotatable rotating side is called a rotating member, and the configuration of each part will be described.

As shown in FIGS. 2 and 3, the pitch joint structure 41 of the ankle joint 23 is composed of a pitch fixed member 41b and a pitch rotating member 41r. is constructed so as to be relatively rotatable about the center of the lower leg portion 14 and the foot portion 15 and is connected and supported.

The pitch fixing member 41b of the pitch joint structure 41 is formed in a short, generally cylindrical shape and is connected to the lower leg frame 31 of the lower leg 14 so as not to rotate relative to it. This pitch fixing member 41b accommodates a pitch axis shaft (first joint shaft) 24 for power supply on a pitch axis 24s that coincides with the axis of the substantially cylindrical shape, and is spaced apart in the axial direction via bearings 58 and 59. supported so as to be relatively rotatable.

In addition, the pitch rotation member 41r of the pitch joint structure 41 is formed in a short, substantially cylindrical shape and is mounted on the outer peripheral side, similarly to the pitch fixed member 41b. The pitch rotating member 41r is connected to a pitch fixing member 41b integrally formed with the lower leg frame 31 so as to be relatively rotatable with a common pitch axis 24s via bearings 55 and 56 arranged at positions spaced apart in the axial direction. Supported. As will be described later, the pitch rotating member 41r is assembled to rotate relative to the pitch fixing member 41b (lower leg frame 31) by receiving rotational power from the pitch axis shaft 24, and is connected to the leg portion 15. .

That is, the pitch joint structure 41 of the ankle joint 23 has the pitch axis 24s as a common axis, and the pitch shaft is relatively rotatably installed inside the pitch fixing member 41b that is connected and fixed integrally with the lower leg frame 31. Through the shaft 24, the pitch rotating member 41r, which is mounted on the outside of the pitch fixing member 41b and is connected to the leg portion 15, is relatively rotated. Therefore, in the structure in which the leg portion 15 is relatively rotated (relatively driven) with respect to the lower leg portion 14, the pitch fixing member 41b constitutes a first relatively immovable member together with the lower leg frame 31, and the pitch rotating member 41r is , constitutes a first relative drive intermediate member capable of relative rotation (relative drive) with respect to the pitch fixing member 41b.

On the other hand, as shown in FIGS. 2 to 4, the roll joint structure 61 of the ankle joint 23 is composed of a roll fixing member 61b and a roll rotating member 61r. The structure 41 is constructed so as to be relatively rotatable about a roll axis 25s orthogonal to the pitch axis 24s of the structure 41, and connects and supports the lower leg 14 and the foot 15. As shown in FIG.

Similar to the pitch fixing member 41b of the pitch joint structure 41, the roll fixing member 61b of the roll joint structure 61 is formed in a short, substantially cylindrical shape, and cannot rotate relative to the pitch rotating member 41r connected to the foot portion 15. connected to The roll fixing member 61b accommodates the roll shaft (second joint shaft) 25 for power supply, which coincides with the axis of the substantially cylindrical shape, and is relatively rotatable via bearings 78 and 79 separated in the axial direction. Support.

Further, the roll rotation member 61r of the roll joint structure 61 is constructed with a base portion 61r1, a facing plate portion 61r2, and a facing accommodation portion 61r3, and the base portion 61r1 is integrally connected to the upper surface of the foot portion 15 in a parallel posture. A facing accommodation portion 61r3 is integrally connected and fixed to the heel 15b side of the base portion 61r1, and a facing plate portion 61r2 is integrally connected and fixed to the toe 15f side of the base portion 61r1. there is In short, the roll rotating member 61r of the roll joint structure 61 is connected and fixed to the base portion 61r1 so that the facing plate portion 61r2 and the facing accommodation portion 61r3 are separated from each other in the direction of the roll axis 25s. In the present embodiment, the case where the base portion 61r1 is installed in parallel with the upper surface of the foot portion 15 will be described as an example, but the present invention is not limited to this, and the relative position with respect to the foot portion 15 will be described. Needless to say, it should be installed in a state where the relationship is fixed.

Among them, the facing plate portion 61r2 is installed at a position facing the facing accommodation portion 61r3 in the direction of the roll axis 25s, and as described later, the pitch rotation member 41r integrated with the roll fixing member 61b accommodated in a relatively rotatable manner. It faces the facing accommodating portion 61r3 so as to be interposed therebetween.

The facing housing portion 61r3 is formed in a short, substantially cylindrical shape like the roll fixing member 61b, and is mounted on the outer peripheral side of the roll fixing member 61b integral with the pitch rotation member 41r. The facing housing portion 61r3 and the facing plate portion 61r2 are integrally rotatably fixed together with the facing plate portion 61r2 through bearings 74 and 75 arranged at positions spaced apart in the axial direction to share the roll axis 25s. It is supported by the member 61b and the pitch rotation member 41r. As will be described later, the facing housing portion 61r3 is assembled so as to receive rotational power from the roll shaft 25 and rotate relative to the roll fixing member 61b and the pitch rotating member 41r together with the facing plate portion 61r2.

That is, the roll joint structure 61 of the ankle joint 23 is relatively rotatably mounted inside the roll fixing member 61b integrated with the pitch rotation member 41r connected to the foot portion 15 with the roll axis 25s as a common axis. The facing housing portion 61r3 of the roll rotating member 61r integrated with the foot portion 15, which is mounted on the outside of the roll fixing member 61b, is relatively rotated together with the facing plate portion 61r2 via the roll shaft shaft 25. there is For this reason, in the structure in which the foot portion 15 is relatively rotated (relatively driven) with respect to the lower leg portion 14, the roll fixing member 61b is integrated with the pitch rotation member 41r so that the relative position and the relative posture do not change. The roll rotating member 61r constitutes a second relatively immovable intermediate member, and the roll rotating member 61r, together with the leg portion 15, constitutes a second relative driving member capable of relative rotation (relative driving) with respect to the roll fixing member 61b. is doing.

Therefore, the pitch joint structure 41 and the roll joint structure 61 of the ankle joint 23 are arranged such that the pitch rotation member 41r rotates around the pitch axis 24s and the roll rotation member 61r rotates around the roll axis 25s with respect to the lower leg 14, respectively. The joint origin (orthogonal point) 27o where the pitch axis 24s and the roll axis 25s intersect (intersect) is integrated with the roll fixing member 61b. is constructed to be positioned within the pitch rotation member 41r of the .

As a result, the ankle joint 23 is arranged such that the pitch axis 24s and the roll axis 25s are orthogonal to each other, and the rotation axes in the pitch direction and the roll direction are on the same level (on the same plane or on the diameter of the strain wave gear reduction devices 42 and 62, which will be described later). The pitch direction and the roll direction when the foot portion 15 (the base portion 61r1 of the roll joint structure 61) is pitched or rolled at the approach position near the lower portion of the lower leg portion 14. and can be rotatably installed in each of them.

The biped robot 10 has a pitch motor 46 (see FIG. 5) and a roll motor 66 (see FIGS. 5 and 6) as power sources for the pitch joint structure 41 and the roll joint structure 61 of the ankle joint 23, respectively. ). The pitch motor 46 is arranged at a position close to the knee joint 22 and away from the roll motor 66 on the upper part of the lower leg 14 which is the pitch fixing member 41b. The roll motor 66 is arranged at a position close to the roll axis shaft 25 above the pitch rotation member 41r connected to rotate integrally with the roll fixing member 61b.

As a result, the ankle joint 23 performs a pitching motion as will be described later by arranging the pitch motor 46 of the pitch joint structure 41 at a position above the roll motor 66 of the roll joint structure 61 to secure a space. , the roll motor 66 that rotates integrally in the pitching direction can be allowed to enter the lower part of the pitch motor 46, and a large rotation range in the pitching direction can be secured.

The pitch joint structure 41 and the roll joint structure 61, as shown in FIGS. and a roll parallel shaft type transmission mechanism 67 to rotate the foot portion 15 relative to the leg portion 14 in the pitch direction and the roll direction. A gear reduction (second strain wave gearing) 62 is incorporated.

Specifically, the pitch strain wave gear reduction device 42 has a so-called cup-shaped harmonic drive (registered trademark) structure in which gears with different numbers of teeth are meshed to reduce and output driving force that is input. there is The pitch strain wave gear reduction device 42 includes a pitch-rigid internal gear (output element) 43 having the largest outer diameter and a pitch-rigid internal gear (output element) 43 that partially meshes with the pitch-rigid internal gear 43 because the number of teeth is different on the inner peripheral side of the pitch-rigid internal gear 43 . A flexible external gear (fixed element) 44, and a pitch wave generator arranged on the inner peripheral side of the pitch flexible external gear 44 to mesh the pitch rigid internal gear 43 with the pitch flexible external gear 44. and a device (input element) 45 . In this pitch wave gear reduction device 42, a pitch rigid internal gear 43, a pitch flexible external gear 44, and a pitch wave generator 45 are concentrically arranged radially with a pitch axis 24s as a common axis. It is incorporated in the pitch joint structure 41 (pitch rotation member 41r) by being placed side by side.

Among them, the pitch rigid internal gear 43 is connected and fixed to the pitch rotating member 41r of the pitch joint structure 41 so as to rotate coaxially about the pitch axis 24s, and is installed rotatably relative to the lower leg 14. It is The pitch flexible external gear 44 is connected and fixed to the pitch fixing member 41b of the pitch joint structure 41, and is installed integrally with the lower leg 14 so as not to rotate relative to it. The pitch wave generator 45 is connected and fixed to the pitch axis shaft 24 of the pitch joint structure 41, and is rotated by the rotational driving force of the pitch motor 46 received via the pitch parallel shaft type transmission mechanism 47 as will be described later.

With this structure, the pitch strain wave gear reduction device 42 is a pitch wave motion generator in a state in which the pitch flexible external gear 44 is connected and fixed to the lower leg 14 via the pitch fixing member 41b of the pitch joint structure 41. 45 is input (supplied) with the rotational driving force of the pitch motor 46 from the pitch shaft 24 of the pitch joint structure 41 via the pitch parallel shaft type transmission mechanism 47 and is rotationally driven, the pitch flexible external gear 44 is rotated. The pitch-rigid internal gear 43 that meshes with the gear rotates at a reduced speed according to the difference in the number of teeth, and outputs rotational driving force.

3 to 5, the pitch parallel shaft type transmission mechanism 47 includes a motor pulley 48 installed on the rotation drive shaft of the pitch motor 46 and a pitch pulley installed on the end of the pitch shaft shaft 24. 49 are arranged vertically so that their axes are parallel to each other, and a timing belt 50 is wound around each of them.

With this structure, the pitch parallel shaft type transmission mechanism 47 is constructed in a transmission structure in which the rotation drive shaft of the pitch motor 46, which is the source and destination of power transmission, and the pitch axis 24s of the pitch shaft 24 are parallel. A simple structure such as a pitch pulley 49 around which the timing belt 50 is wound (or a gear train) can be arranged on one side in the axial direction to transmit the rotational driving force of the pitch motor 46 . As shown in FIGS. 5 and 6, the pitch parallel shaft type transmission mechanism 47 transmits the rotational driving force of the pitch motor 46 to the pitch shaft shaft 24 to transmit the pitch wave motion generator 45 of the pitch strain wave gear reduction device 42 to the pitch wave motion generator 45 . It can be transmitted to the pitch rotation member 41r side (leg portion 15) of the pitch joint structure 41 via the rigid internal gear 43, and relatively rotated in the pitch direction.

Also, in this pitch strain wave gear reduction device 42, the pitch rigid internal gear 43 is arranged in the vicinity of the joint origin 27o at which the pitch axis 24s and the roll axis 25s intersect each other. As a first advantage of this arrangement, this arrangement makes it possible to form the pitch fixing member 41b that is more compact in the radial direction of the pitch axis 24s than a general-purpose gear train structure in which the tooth flanks of the outer peripheral surface are meshed with each other. The ankle joint 23 can be made compact.

In addition, as a second advantage of this arrangement, this arrangement allows the pitch flexible external gear 44 of the pitch wave gear reduction device 42 and the pitch wave generator 45 to move in one direction with the pitch axis 24s with the joint origin 27o as a boundary. As a result, a wiring hole 54 for wiring a cable, which will be described later, can be provided on the opposite side of the pitch axis 24s.

Furthermore, as a third advantage of this arrangement, the pitch fixing member 41b can be formed with a compact radial direction of the pitch axis 24s, and the pitch joint structure 41 can be formed with a compact radial direction of the roll axis 25s, and the foot portion 15 can be formed. When rotating in the roll direction, the range in which the pitch joint structure 41 and the foot 15 can move without interfering with each other is widened, so that the ankle height can be kept low and the rotation angle in the roll direction can be increased.

Similarly, as shown in FIGS. 2 to 4, the roll strain wave gear reduction device 62 includes a roll rigid internal gear (output element) 63 having the largest outer diameter and an internal gear of the roll rigid internal gear 63. A roll flexible external gear (fixed element) 64 that is partially meshed with a different number of teeth on the peripheral side, and a roll rigid internal gear 63 that is arranged on the inner peripheral side of the roll flexible external gear 64. and a roll wave generator (input element) 65 with which a roll flexible external gear 64 is meshed, and is constructed in a so-called cup-shaped harmonic drive (registered trademark) structure. In this roll wave gear reduction device 62, a roll rigid internal gear 63, a roll flexible external gear 64, and a roll wave generator 65 are concentrically arranged radially with the roll axis 25s as a common axis. It is incorporated in the roll joint structure 61 (the facing accommodation portion 61r3) by being juxtaposed to the .

Of these, the roll rigidity internal gear 63 is connected and fixed to the facing accommodating portion 61r3 of the roll rotation member 61r of the roll joint structure 61 so as to rotate coaxially about the roll axis 25s. It is installed integrally so as not to rotate. The roll flexible external gear 64 is connected and fixed to the roll fixing member 61b of the roll joint structure 61 and installed to be relatively rotatable with respect to the leg portion 15 . The roll wave generator 65 is connected and fixed to the roll axis shaft 25 of the roll joint structure 61, and is rotated by the rotational driving force of the roll motor 66 received via the roll parallel shaft type transmission mechanism 67 as described later.

With this structure, the roll wave gear reduction device 62 is a roll wave generator in a state in which the roll flexible external gear 64 is connected and fixed to the pitch rotation member 41r integral with the roll fixing member 61b of the roll joint structure 61. 65 is rotationally driven by input (supply) of the rotational driving force of the roll motor 66 from the roll shaft 25 of the roll joint structure 61 via the roll parallel shaft type transmission mechanism 67, and the roll flexible external gear 64 is driven. The roll-rigid internal gear 63 meshing with the gear rotates at a reduced speed according to the difference in the number of teeth, and outputs a rotational driving force.

4 to 6, the roll parallel shaft type transmission mechanism 67 includes a motor pulley 68 installed on the rotary drive shaft of the roll motor 66 and a roll shaft installed at the end of the roll shaft 25. The pulleys 69 are arranged vertically so that their axes are parallel to each other, and a timing belt 70 is wound around each of them.

With this structure, the roll parallel shaft type transmission mechanism 67 is constructed in a transmission structure in which the rotation drive shaft of the roll motor 66, which is the power transmission source and the transmission destination, and the roll axis 25s of the roll shaft 25 are parallel. A simple structure such as a roll pulley 69 around which the timing belt 70 is wound (or a gear train) can be arranged on one side in the axial direction to transmit the rotational driving force of the roll motor 66 to the roll shaft 25 . As shown in FIGS. 7 and 8, the roll parallel shaft type transmission mechanism 67 transmits the rotational driving force of the roll motor 66 to the roll shaft 25 to transmit the roll vibration generator 65 of the roll wave gear reduction device 62 to the roll. Via the rigid internal gear 63, the side of the roll rotation member 61r of the roll joint structure 61 facing the housing portion 61b3 (foot portion 15) can be relatively rotated in the roll direction.

The roll strain wave gear reduction device 62 is arranged behind the pitch rotation member 41r (on the side of the heel 15b of the foot portion 15) and close to the pitch strain wave gear reduction device 42 (pitch axis 24s). As described above, the roll motor 66 is arranged at a position close to the roll axis shaft 25 above the pitch rotation member 41r. An ankle joint 23 with 41 can be realized. That is, the rotation angle in the pitch direction can also be increased.

In addition, generally, in a bipedal robot, for example, the size of the sole 15s is often long in the front-rear direction and short in the left-right direction in a substantially rectangular shape, as in the present embodiment. Therefore, the roll torque around the roll axis 25s is smaller than the pitch torque around the pitch axis 24s, and as a result, the roll wave gear speed reducer 62 uses a speed reducer with a lower output (smaller size) than the pitch wave gear speed reducer 42. and the roll strain wave gear reduction device 62 having a small radial direction (outer diameter) can be employed. Therefore, it is possible to reduce the diameter of the facing accommodation portion 61r3 of the roll rotation member 61r, which is the casing member of the roll strain wave gear reduction device 62, so that the degree of freedom in layout of the ankle joint 23 can be improved. The angle of rotation in direction can also be increased.

Therefore, in the ankle joint 23, the outer shape of the facing plate portion 61r2, which relatively rotatably supports the roll fixing member 61b that rotates integrally with the pitch rotation member 41r via the bearing 74, can be made compact. The outer diameter of the opposing housing portion 61r3, which is relatively rotatably supported, is also reduced. The thickness can be reduced (thin) to provide a compact structure. Therefore, even when rotating (moving) in two directions about both the pitch axis 24s and the roll axis 25s, interference between the lower leg 14 and the foot 15 is unlikely to occur (single movement about one axis). Without narrowing the movable range that could be achieved with axial movement), it is possible to realize a joint that maintains a wide movable range in two directions.

In addition, the roll fixing member 61b is screwed and fixed to the roll flexible external gear 64 and is housed inside the facing housing portion 61r3 of the roll rotating member 61r. As a result, the facing housing portion 61r3 of the roll rotating member 61r and the end portion of the roll fixing member 61b in the direction of the roll axis 25s can be arranged at a position close to the pitch shaft 24 side, and a force sensor 81, which will be described later, can be arranged. It is possible to increase the rigidity of the roll rotating member 61r which is connected to and supported by the foot portion 15 and receives a landing impact force from the floor surface.

As a result, in the ankle joint 23, the joint origin 27o where the pitch axis 24s and the roll axis 25s of the pitch wave gear reduction device 42 and the roll wave gear reduction device 62 intersect is in the same horizontal plane, or at least the outer diameter (in the vertical direction) (less than the thickness of ), and a facing housing portion 61r3 for the roll rotation member 61r housing the roll wave gear speed reducer 62 is arranged near the pitch axis 24s of the pitch wave gear speed reducer 42. ing. Therefore, the ankle joint 23 can have a compact structure around the pitch axis 24s and the roll axis 25s, and can secure a large rotatable angle range while suppressing the height of the ankle.

In the ankle joint 23 of the biped robot 10, as shown in FIGS. 5 and 6, the pitch motor 46 and the roll motor 66 are above the joint origin 27o, which is the orthogonal point between the pitch axis 24s and the roll axis 25s. Similarly, the rotary drive shafts are arranged in the lower leg 14 so as to be perpendicular to each other. The ankle joint 23 is driven by the rotation driving force of the motors 46 and 66 to pitch through a simple pitch parallel shaft type transmission mechanism 47 and a roll parallel shaft type transmission mechanism 67 in which timing belts 50 and 70 are wound around pulleys 49 and 69, respectively. It is transmitted to the axis shaft 24 and the roll axis shaft 25 . At the ankle joint 23, a pitch wave gear reduction device 42 and a roll wave gear reduction device 62 having substantially cylindrical components are arranged around the pitch axis shaft 24 and the roll axis shaft 25. , the transmitted rotational driving force is input and output to relatively rotate the foot portion 15 in the pitch direction and the roll direction.

With this structure, in the biped robot 10, the area around the pitch axis 24s and the roll axis 25s of the ankle joint 23 is made compact, and the lower leg 14 having a structure having rigidity on the side of the knee joint 22 (thigh 13) is provided. I have. Therefore, in the bipedal robot 10, the base portion 61r1 of the roll joint structure 61 can be installed in the vicinity of the roll axis 25s or the like to reduce the height of the ankle joint 23 from the foot portion 15. A space is secured on the lower leg 14 side in which the body 15 rotates deeply in the pitch direction and the roll direction around the pitch axis 24s and the roll axis 25s. Specifically, as shown in FIG. 7, the ankle joint 23 can largely rotate the foot portion 15 in the pitch direction until the facing housing portion 61r3 of the roll joint structure 61 abuts the lower leg portion 14. The foot 15 can be rotated in the opposite direction until it is parallel to the lower leg 14, as shown in FIG. 14 can be largely rotated in the roll direction around the roll axis 25s. Together, as shown in FIG. 11 and FIG. It can be rotated greatly in the pitch and roll directions.

As shown in FIGS. 2 to 6, the biped robot 10 includes sensors for acquiring various information about the ankle joint 23, such as motor shaft angle sensors (first and second drive rotation angle sensors) 51 and 71. , output shaft angle sensors (first and second relative rotation angle sensors) 52 and 72, and a force sensor 81 are installed at various locations. Various sensors including these send their detection information to a control unit 100 (see FIG. 17) constituting detection means (described later) installed in the chest 16 via a signal line passing through the lower leg 14. Retrievably cabled. In this embodiment, a case where the biped robot 10 is centrally managed and controlled by the control unit 100 of the chest 16 will be described as an example. Alternatively, the controllers installed in each of them may perform decentralized management control.

Specifically, the motor shaft angle sensors 51, 71 are installed on opposite sides of the respective motor pulleys 48, 68 so as to detect the rotation angles of the rotary drive shafts of the pitch motor 46 and the roll motor 66, and sensor cable 51c. , 71c are respectively connected. The output shaft angle sensors 52, 72 correspond to the pitch rotation member 41r of the pitch joint structure 41 and the roll rotation member 61r of the roll joint structure 61, which are connected so as to integrally rotate about the pitch axis 24s and the roll axis 25s, respectively. Sensor cables 52c and 72c are installed and connected to detect relative rotation angles of the lower leg frame 31 and the roll fixing member 61b of the roll joint structure 61, respectively. The force sensor 81 is installed between the base portion 61r1 of the roll joint structure 61 and the foot portion 15 so as to detect the distribution of force acting on the foot portion 15, and is connected to a sensor cable 81c. The pitch motor 46 and the roll motor 66 are connected to power cables 46c and 66c, respectively, through which currents flow when they are rotationally driven. Here, the force sensor 81 detects not only the force acting on the sole 15s of the foot portion 15, but also the force generated (acted) when, for example, a person stumbles, and also detects the force acting on the cover installed on the foot portion 15. will do.

As for these cable layouts, the ankle joint 23 of the biped robot 10 has wiring holes 32, 53a, 53b through which sensor cables 52c, 71c, 72c, 81c and a power cable 66c pass, as shown in FIGS. , 54 and 73 are installed.

A wiring hole (first wiring passage hole) 32 is formed and opened in the lower leg frame 31 located on the opposite side of the pitch pulley 49 with the pitch axis shaft 24 interposed therebetween. Similar to the pitch fixing member 41b of the pitch joint structure 41, the lower leg frame 31 supports the pitch rotating member 41r relatively rotatably about the pitch axis 24s through the bearing 55. Inside the lower leg frame 31, it is formed in a circular opening shape centering on the pitch axis 24s.

The wiring hole 73 (second wiring passage hole) is supported by the facing plate portion 61r2 of the roll joint structure 61 via a bearing 74 so as to be relatively rotatable about the roll axis 25s. formed and opened. The wiring hole 73 is formed in a circular opening shape centering on the roll axis 25s in the pitch rotation member 41r of the pitch joint structure 41. As shown in FIG.

The wiring hole (communication wiring passage hole) 54 is formed in the pitch rotation member 41r of the pitch joint structure 41 located inside the wiring hole 32 as a substantially disc-shaped space coaxial with the pitch axis 24s. The wiring hole (communication wiring passage hole) 53a is a space that allows the wiring hole 73 at one end of the pitch rotation member 41r of the pitch joint structure 41 to communicate with the substantially disk-shaped wiring hole 54 at the adjacent position. In short, these wiring holes 53a and 54 are communicated so that a cable can be passed between the openings of the wiring holes 32 and 73. As shown in FIG. Further, as shown in FIG. 12, the wiring hole 53b is formed by cutting out a part of the ceiling surface of the pitch rotation member 41r of the pitch joint structure 41 on the side of the roll motor 66 to pass the cable through an opening exposed to the outside. is formed so that Here, the space formed as the wiring hole 54 is not limited to a disc shape, and needless to say, any space that allows cable wiring may be secured.

With these structures, the power cable 46c of the pitch motor 46 and the sensor cable 51c of the motor shaft angle sensor 51 are positioned above the ankle joint 23 and are immovable within the lower leg frame 31. It can be set through so as to face the 16 side. Therefore, the power cable 46c and the sensor cable 51c will not be disconnected due to the movement of the leg 15, and the movement of the leg 15 will not be restricted.

The power cable 66c of the roll motor 66 and the sensor cable 71c of the motor shaft angle sensor 71 are inserted from the roll motor 66 through the wiring hole 53b of the pitch rotation member 41r, and are pulled out from the wiring hole 54 through the wiring hole 32. Later, it can be installed so as to pass from the inside of the crus 14 toward the chest 16 side. Since the roll motor 66 is attached to the pitch rotation member 41r to which the roll fixing member 61b is connected and fixed and rotates integrally, the positional relationship with respect to the opening of the wiring hole 53b opened on the outer surface of the pitch rotation member 41r is the foot portion 15. It does not change with the operation of In addition, the length of the route passing through the wiring holes 54 and 32 connected to the wiring hole 53b does not change due to the movement of the leg portion 15. FIG. Furthermore, the opening of the wiring hole 32 is opened on the pitch axis 24s of the rotation center of the pitch rotation member 41r supported so as to be relatively rotatable with respect to the lower leg frame 31. It will not be changed by the operation of Therefore, the power cable 66c and the sensor cable 71c are not loosened by the movement of the leg 15, and there is no risk of disconnection due to being pulled. While avoiding, the movement of the foot part 15 is not restricted.

The output shaft angle sensor 52 is composed of a reading ring 52r and a reading head 52h arranged so as to face the pitch fixing member 41b and the pitch rotating member 41r, which sandwich the plane orthogonal to the pitch axis 24s of the pitch joint structure 41. there is A reading ring 52r of the output shaft angle sensor 52 is formed in a ring shape so as to be positioned around the pitch axis 24s and installed on the pitch fixing member 41b. On the other hand, the reading head 52h is located above the pitch rotation member 41r and arranged to detect the rotational position of the reading ring 52r. The output shaft angle sensor 52 has a sensor cable 52c connected to a reading head 52h positioned above the pitch rotation member 41r near the roll motor 66. Similarly, the wiring holes 53b, 54, 32 of the pitch rotation member 41r are connected to the controller 100 of the chest 16 from the inside of the leg 14. As shown in FIG. Since the sensor cable 52c also does not change its positional relationship with respect to the lower leg frame 31 due to the movement of the foot part 15, there is no fear of disconnection, and contact with the outside through the inside of the ankle joint 23 can be avoided in advance. At the same time, the movement of the foot portion 15 is not restricted.

Similarly to the output shaft angle sensor 52, the output shaft angle sensor 72 faces each of the facing housing portions 61r3 of the roll fixing member 61b and the roll rotation member 61r that sandwich the plane orthogonal to the roll axis 25s of the roll joint structure 61. It is composed of a reading ring 72r and a reading head 72h that are arranged. A reading ring 72r of the output shaft angle sensor 72 is formed in a ring shape so as to be positioned around the roll axis 25s and installed on the roll fixing member 61b. On the other hand, the reading head 72h is located on the side of the facing accommodating portion 61r3 of the roll rotating member 61r and arranged so as to detect the rotational position of the reading ring 72r. The output shaft angle sensor 72 has a sensor cable 72c connected to a reading head 72h positioned on the side of the facing housing portion 61r3 of the roll rotation member 61r. , and connected to the controller 100 of the chest 16 from within the crus 14 through the wiring holes 53a, 54, and 32 from the wiring hole 73 of the pitch rotation member 41r. By the way, since the roll rotating member 61r is fixed to the leg portion 15 side and its relative posture is immovable, the path to the wiring hole 73 of the sensor cable 72c of the output shaft angle sensor 72 is not affected by the movement of the leg portion 15. Moreover, since the length of the route from the wiring hole 73 through the wiring holes 53a, 54, 32 does not change due to the movement of the leg 15, the length of the lower leg at the opening of the wiring hole 32 does not change. The positional relationship with respect to the frame 31 does not change due to the movement of the leg portion 15. - 特許庁Therefore, the positional relationship of the sensor cable 72c with respect to the lower leg frame 31 does not change due to the movement of the foot 15, so there is no fear of disconnection and contact with the outside through the ankle joint 23 is prevented. While avoiding, the movement of the foot part 15 is not restricted.

Similarly to the sensor cable 72c of the output shaft angle sensor 72, the sensor cable 81c of the force sensor 81 is routed from the lower side of the base portion 61r1 of the roll joint structure 61 between the foot portion 15 and the wiring hole of the pitch rotation member 41r. Through 73 , 53 a , 54 , 32 , it is connected to the controller 100 of the chest 16 from within the lower leg 14 . The sensor cable 81c of the force sensor 81 is also fixed to the foot portion 15 side together with the roll fixing member 61b so that its relative posture is immovable, and the route, its length, and the position of the wiring hole 73 change with the movement of the foot portion 15. Therefore, there is no fear of disconnection, contact with the outside through the inside of the ankle joint 23 is avoided, and the movement of the foot portion 15 is not restricted.

As shown in FIGS. 13 to 17, the ankle joint 23 of the biped robot 10 has a pitch joint structure in a space where the lower part of the lower leg frame 31 is recessed in an inverted U shape when viewed from the direction of the roll axis 25s. 41 is rotatably supported by the pitch axis shaft 24 . The ankle joint 23 is housed together with the roll motor 66 with an integrally rotating ankle cover 84 attached to the upper side of the pitch joint structure 41 .

Specifically, the ankle cover 84 includes a circular ankle outer peripheral surface (curved surface) 84 a centered on the pitch axis 24 s of the axis common to the pitch joint structure 41 , and the lower leg frame 31 on both ends of the pitch axis shaft 24 . It has both side surfaces 84s facing the inner surface of the . The ankle cover 84 is a circular disc having a thickness of a semicircle that can rotate in the lower space of the lower leg frame 31 while housing the pitch joint structure 41 on the upper side of the pitch axis shaft 24, the roll motor 66, and the like. It is made into a shape and is screwed and fixed to the pitch rotation member 41r with a screw N. As shown in FIG. As a result, the ankle cover 84 covers the upper side of the ankle joint 23 together with the pitch joint structure 41 of the ankle joint 23, the roll motor 66, and the various cables 52c, 66c, and 71c so that the cables 52c, 66c, and 71c are not exposed and caught, and the foot portion 15 rolls. It is installed so as to be integrally rotatable in the pitch direction about the pitch axis 24s while allowing relative rotation in the direction.

On the other hand, the lower leg frame 31 has a lower ceiling surface 31u that faces the ankle outer peripheral surface 84a of the ankle cover 84 through a small gap. is formed into a circular curved shape centered on the pitch axis 24s. As a result, the crus frame 31 and the ankle cover 84 face the lower ceiling surface 31u and the ankle outer peripheral surface 84a through a narrow gap, which is close to each other, so as to be relatively rotatable. It is also possible to prevent the various cables 66c and the like inside from being exposed to the outside and getting caught.

This bipedal walking robot 10 can acquire information detected by various sensors 51, 52, 71, 72, and 81 via various cables 51c and the like connected to the control unit 100 (see FIG. 17) of the chest 16. The control unit 100 executes a control program stored in advance in the memory 101 to walk the left and right legs 12 together with the arms 17 based on various setting parameters and various sensor detection information. make it work. At this time, the control unit 100 drives the pitch motor 46 and the roll motor 66 independently or cooperatively in forward and reverse directions to adjust the foot portion 15 to a desired relative rotation angle so that the sole 15s is aligned with the floor surface or the like. Maintain a stable posture while keeping them close evenly. As the parameters used by the control unit 100, for example, the speed reduction ratio of the parallel shaft type transmission mechanism, the speed reduction ratio of the wave gear device, etc. are set in advance.

For example, the control unit 100 multiplies the sensor detection information of the motor shaft angle sensor 51 of the pitch motor 46, the speed reduction ratio of the pitch strain wave gear reduction device 42, and the speed reduction ratio of the pitch parallel shaft type transmission mechanism 47 to obtain a , the relative rotation angle (equivalent pitch output shaft angle calculated value) between the pitch fixing member 41b (lower leg frame 31) and the pitch rotating member 41r around the pitch axis 24s. Similarly, the control unit 100 multiplies the sensor detection information of the motor shaft angle sensor 71 of the roll motor 66, the reduction ratio of the roll wave gear reduction device 62, and the reduction ratio of the roll parallel shaft type transmission mechanism 67, for example. In addition, the relative rotation angle (equivalent roll output shaft angle calculated value) between the roll fixing member 61b (pitch rotation member 41r) and the roll rotation member 61r (foot portion 15) around the roll axis 25s is calculated.

Further, the control unit 100, for example, calculates a pitch subtraction value, which is the difference between the above equivalent pitch output shaft angle calculation value and the sensor detection value of the pitch output shaft angle sensor 52, and similarly calculates the above equivalent pitch output shaft angle value. A roll subtraction value, which is the difference between the roll output shaft angle calculation value and the sensor detection value of the roll output shaft angle sensor 72, is calculated.

Here, when the bipedal walking robot 10 is operating normally without any abnormality such as loosening of the screw fastening at various places in the ankle joint 23 and ratcheting in the wave gear reduction devices 42 and 62, the above equivalent pitch output The shaft angle calculation value and the sensor detection value of the pitch output shaft angle sensor 52 match, and the equivalent roll output shaft angle calculation value and the sensor detection value of the roll output shaft angle sensor 72 also match.

Therefore, in the control unit 100, when the absolute value of the calculated pitch subtraction value exceeds a preset minute threshold (a minute value that depends on the resolution of the sensor), the lower leg frame 31 and the pitch It is possible to detect the occurrence of an abnormality such as loosening of screw fastening or ratcheting in the pitch strain wave gear reduction device 42 in one or both of the joint structures 41 . Similarly, when the absolute value of the calculated roll subtraction value exceeds the set minute threshold value, the control unit 100 controls the loosening of the screw fastening and the deceleration of the roll strain wave gear in one or both of the pitch joint structure 41 and the roll joint structure 61. Abnormal occurrence such as ratcheting in the device 62 can be detected.

When this abnormality occurs, the control unit 100 executes a control process for safely stopping the bipedal robot 10 to prevent an accident or the like from occurring. It should be noted that the stop control process can be performed by executing an existing technique, which is described, for example, in Japanese Unexamined Patent Application Publication No. 2007-30078.

As described above, in the ankle joint 23 of the biped robot 10 of the present embodiment, the pitch wave gear reduction device 42 is arranged between the bearings 55 and 56 to support the roll wave gear reduction device 62. Positioned between 74 and 75, the pitch axis 24s and the roll axis 25s are orthogonal to each other. Relative rotation can be realized. The pitch strain wave gear reduction device 42 and the roll strain wave gear speed reduction device 62 are connected to a simple pitch parallel shaft type transmission mechanism 47, in which timing belts 50 and 70 are wound around the rotational driving force of the pitch motor 46 and the roll motor 66, respectively. Since the rotational driving force can be transmitted by the roll parallel shaft type transmission mechanism 67, it is possible to control the driving individually and mount it compactly with a simple transmission mechanism.

Therefore, the bipedal walking robot 10 can simplify the area around the ankle joint 23 to improve the degree of freedom of layout, and rotate the leg 15 in the pitch direction and the roll direction with simple control by the lower ankle joint 23. It can be made to walk comfortably even on uneven terrain with unevenness.

Here, in this embodiment, as described above, the harmonic drive (trade name: registered trademark) is used for the pitch strain wave gear reduction device 42 and the roll strain wave gear reduction device 62, and the pitch rigid internal gear 43 and the roll A circular spline in a harmonic drive is used for the rigid internal gear 63, a flexspline in a harmonic drive is used for the pitch flexible external gear 44 and the roll flexible external gear 64, and a pitch wave generator 45 and a roll wave are used. A wave generator in harmonic drive is used for the generator 65 . However, it is not necessary to be limited to this harmonic drive, and for example, a flexwave speed reducer (trade name: registered trademark) may be used. More specifically, the pitch rigid internal gear 43 and the roll rigid internal gear 63 are the internal gears of the flexwave speed reducer, and the pitch flexible external gear 44 and the roll flexible external gear 64 are the flexwave speed reducer. The flex gear may be used for the pitch wave generator 45 and the roll wave generator 65, and the elastic bearings and cams of the flex wave reducer may be used.

Furthermore, in this embodiment, a case where the pitch axis 24s and the roll axis 25s are orthogonal to each other will be described as an example, but it is needless to say that the present invention is not limited to this, and can be applied to a form in which they intersect at an angle other than a right angle. stomach.

In addition, in the wrist joint of a manipulator that imitates an arm, it is similar to the above-mentioned ankle joint. Desired. For this reason, the ankle joint 23 can also be suitably applied to the wrist joint.

The scope of the invention is not limited to the illustrated and described exemplary embodiments, but also includes all embodiments that provide equivalent results for which the invention is intended. Furthermore, the scope of the invention is not limited to the combination of inventive features defined by each claim, but may be defined by any desired combination of the particular features of each of the disclosed features. .

10 Biped robot 14 Lower leg 15 Foot 15 s Sole 23 Ankle joint 24 Pitch axis shaft 24 s Pitch axis 25 Roll axis shaft 25 s Roll axis 27o... Joint origin 31... Lower leg frame 31u... Lower ceiling surface 32, 53, 54, 73... Wiring hole 41... Pitch joint structure 41b... Pitch fixing member 41r... Pitch rotating member 42... Pitch wave motion Gear speed reducer 43 Pitch rigid internal gear 44 Pitch flexible external gear 45 Pitch wave generator 46 Pitch motors 46c, 66c Power cable 47 Pitch parallel shaft transmission mechanism 51 , 71... Motor shaft angle sensors 51c, 52c, 71c, 72c, 81c... Sensor cables 52... Pitch output shaft angle sensors 55, 56, 58, 59, 74, 75, 78, 79... Bearings 61... Roll joint structure 61b Roll fixing member 61r Roll rotating member 62 Roll wave gear reduction device 63 Roll rigid internal gear 64 Roll flexible external gear 65 Roll wave generator 66 Roll motor 67 Roll parallel shaft type transmission mechanism 72 Roll output shaft angle sensor 81 Force sensor 84 Ankle cover 84a Ankle outer peripheral surface 100 Control unit 101 Memory

Claims (11)

A main body device comprising a first strain wave gear device composed of various elements relatively rotating about a first joint axis and a second strain wave gearing composed of various elements relatively rotating about a second joint axis A joint structure mounted on a
The first strain wave gearing includes a first input element to which a rotational driving force about the first joint shaft is transmitted and input from a first motor, and the second strain wave gearing drives the rotation about the second joint shaft. comprising a second input element to which force is transmitted and input from the second motor;
The first joint shaft and the second joint shaft are located on the same plane or within a range smaller than the vertical thickness of the first strain wave gearing or the second strain wave gearing so that they intersect. placed,
The first strain wave gear device has a first fixed element fixed to the first relatively immovable member and a first output element fixed to the first relative drive intermediate member,
The second strain wave gear device has a second fixed element fixed to the second relatively immovable intermediate member and a second output element fixed to the second relative drive member,
The first relatively driving intermediate member and the second relatively immovable intermediate member are configured such that their relative positions and relative postures do not change,
The first strain wave gearing is arranged on the axis of the second joint shaft,
The first motor for transmitting and inputting rotational power to the first input element of the first strain wave gearing is arranged on the first relatively immovable member ,
The second motor, which transmits and inputs rotational power to the second input element of the second strain wave gearing, straddles one or both of the first relatively driving intermediate member and the second relatively immovable intermediate member. A joint structure characterized by being arranged . The second motor is arranged on a straight line that passes through the intersection of the first joint axis and the second joint axis and is orthogonal to both the first joint axis and the second joint axis. The articulated structure according to claim 1 . The first strain wave gearing and the second strain wave gearing include wave generators as the first input element and the second input element, respectively, and flexible external gears as the first fixed element and the second fixed element, respectively. 3. The joint structure according to claim 1 or 2 , comprising tooth gears, rigid internal gears as said first output element and said second output element, respectively. 2. The first motor has a rotary drive shaft parallel to the first joint shaft, and transmits and inputs a rotary drive force to the first input element of the first wave gear device. 4. The articulated structure according to any one of claims 3 . 2. The second motor has a rotary drive shaft parallel to the second joint shaft, and transmits and inputs a rotary drive force to the second input element of the second strain wave gear device. 4. The articulated structure according to any one of claims 3 . a first wiring passage hole formed in a path through which the first joint shaft passes; a second wiring passage hole formed in a route through which the second joint shaft passes; 6. The joint structure according to any one of claims 1 to 5 , further comprising a communication wire passage hole formed in an intervening member so as to communicate with the second wire passage hole. a cover covering all or part of components that rotate relative to each other with the second relatively immovable intermediate member and the first relatively driving intermediate member about the first joint shaft;
The cover has a curved surface centered on the first joint shaft, and the first relatively immovable member has a similar concave shape that closely faces the curved surface of the cover. The joint structure according to any one of claims 1 to 6 . A joint drive device comprising the joint structure according to any one of claims 1 to 7 ,
the first motor;
the second motor;
a first drive rotation angle sensor for detecting a drive rotation angle of the rotation drive shaft of the first motor;
a second drive rotation angle sensor for detecting a drive rotation angle of the rotation drive shaft of the second motor;
a first relative rotation angle sensor for detecting a relative rotation angle between the first fixed element and the first output element of the first strain wave gearing;
a second relative rotation angle sensor for detecting the relative rotation angle between the second output element and the second fixed element of the second strain wave gearing;
with
According to the detection value of the first drive rotation angle sensor, a speed reduction ratio for transmitting the rotational driving force from the rotary drive shaft of the first motor to the first input element of the first wave gear device and the first wave gear device of the first wave gear device calculating a first subtraction value by subtracting the detection value of the first relative rotation angle sensor from an integrated value obtained by integrating the speed reduction ratio from the one input element to the first output element;
According to the detection value of the second driving rotation angle sensor, a speed reduction ratio for transmitting the rotational driving force from the rotary drive shaft of the second motor to the second input element of the second wave gear device and the second wave gear device of the second wave gear device calculating a second subtraction value by subtracting the detection value of the second relative rotation angle sensor from an integrated value obtained by integrating the speed reduction ratio from the two input elements to the second output element;
A detecting means for detecting an abnormality of the joint structure based on either one of the first subtraction value and the second subtraction value, or both the first subtraction value and the second subtraction value. joint drive. The joint structure according to any one of claims 1 to 7 is provided as an ankle joint that performs pitching and rolling motions at an ankle that connects the lower leg and the foot. bipedal robot. A bipedal walking robot comprising the joint driving device according to claim 8 . The joint structure according to any one of claims 1 to 7 is provided as an ankle joint that performs pitching and rolling motions in the ankle that connects the lower leg and the foot, and A bipedal robot comprising the joint driving device according to claim 8 .

Images