JP4564028B2 - Leg structure of legged mobile robot - Google Patents

Description

  The present invention relates to a leg structure of a legged mobile robot, and more particularly to a lower leg portion connected to a lower end of an upper leg portion via a knee joint, and a foot portion connected to a lower end of the lower leg portion via an ankle joint. The present invention relates to a leg structure of a legged mobile robot that supports a foot part so that it can be pitched around a left and right axis and can roll around a front and rear axis.

The leg structure of such a legged mobile robot is known from Patent Document 1 below. This is a pitching motor provided at a position near the upper end of the lower leg part, and the foot part is pitched around the pitching shaft part via the belt transmission means with respect to the lower leg part, and the rolling is perpendicular to the pitching shaft part. A rolling motor provided on the shaft part rolls the foot part with respect to the lower leg part.
Japanese Patent Laid-Open No. 3-184782

  By the way, in the above-mentioned conventional one, although the pitching motor is arranged at the upper part of the lower leg part, that is, near the knee joint, the rolling motor is arranged at the lower part of the lower leg part, that is, in the vicinity of the ankle joint. There is a problem that the position of the ankle joint from the floor surface becomes high, the amount of compliance control of the ankle joint becomes large, and it becomes difficult to quickly cope with unexpected irregularities and inclinations of the floor surface.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to make it possible to quickly cope with unexpected irregularities and inclinations of the floor surface by lowering the position of the ankle joint from the floor surface.

To achieve the above object, according to the invention described in claim 1, with connecting the lower leg via the knee joint to the lower end of the upper leg portion, through the ankle joint of the foot to the lower end of the lower leg The ankle joint is a leg structure of a legged mobile robot that supports the lower leg part so that the foot part can be pitched around the left and right axis and can be rolled around the front and rear axis line. The rolling mechanism for supporting the foot part in a freely rolling manner includes a rolling shaft part fixed so as to be orthogonal to the pitching shaft part, and a rolling member fixed to the foot part and rotatably supported on the outer periphery of the rolling shaft part. And a driving bevel gear disposed coaxially in the pitching shaft portion, and a rolling belt transmission means for transmitting the rotation of the output shaft of the rolling motor disposed in the left-right axis direction to the driving bevel gear. Leg structure of the legged mobile robot is characterized in that a driven bevel gear coupled to the rolling member with meshes coaxially disposed in driven bevel gear in the rolling shaft portion is proposed.

  According to the above configuration, the rolling member integrally provided with the foot portion is rotatably supported on the outer periphery of the rolling shaft portion fixed so as to be orthogonal to the pitching shaft portion, and the rotation of the output shaft of the rolling motor is prevented from rolling. This is transmitted to the rolling member via the belt transmission means, the driving bevel gear arranged coaxially in the pitching shaft portion, and the driven bevel gear arranged coaxially in the rolling shaft portion, so that the pitching of the foot portion is affected. The foot can be rolled independently, and can be freely pitched while the foot is rolled. In addition, since the position of the rolling shaft and the pitching shaft can be lowered, compliance control of the ankle joint can be realized with a smaller amount of control, and it is stable in response to unexpected irregularities and inclinations on the floor surface. Can be able to walk.

According to the second aspect of the present invention, in addition to the configuration of the first aspect , the pitching speed reducer is disposed between the pitching belt transmission means and the pitching shaft portion, and the rolling bevel gear is interposed between the driven bevel gear and the rolling member. A leg structure of a legged mobile robot characterized by arranging a reduction gear is proposed.

  According to the above configuration, since the pitching speed reducer is disposed between the pitching belt transmission means and the pitching shaft portion, the load on the pitching motor can be reduced, and the rolling speed reducer is between the driven bevel gear and the rolling member. The load on the rolling motor can be reduced.

According to the invention described in claim 3 , in addition to the configuration of claim 1 or claim 2 , the outer side of the rolling member is covered with a partial spherical cover, and the lower end of the lower leg link constituting the skeleton of the lower leg portion is provided. A leg structure for a legged mobile robot is proposed in which a predetermined gap is formed between the cover and the partial spherical cover.

  According to the above configuration, since the predetermined gap is formed between the partial spherical cover that covers the outside of the rolling member and the lower end of the lower leg link, even if the foot is pitched and rolled, the partial spherical cover and the lower leg link are not separated. It is possible to prevent a large gap from being generated and effectively prevent foreign matter from being caught.

According to the invention described in claim 4 , in addition to the structure of claim 3 , a legged mobile robot characterized in that the partial spherical cover has a center on the pitching shaft portion or the rolling shaft portion. A leg structure is proposed.

  According to the above configuration, since the center of the partial spherical cover is on the pitching shaft portion or the rolling shaft portion, the gap generated between the partial spherical cover and the lower leg link is constant when the foot portion is pitched or rolled. Thus, the partial spherical cover can be prevented from interfering with the lower leg link, and the movable range of the ankle joint can be expanded, thereby preventing foreign objects from being caught more effectively.

According to the invention described in claim 5 , in addition to the configuration of any one of claims 1 to 4 , a sensor for detecting a load applied to the foot is provided in the foot. A leg structure of a legged mobile robot is proposed.

  According to the above configuration, since the positions of the pitching motor and the rolling motor are far from the foot, the sensor provided on the foot is hardly affected by the noise of the motor, and the detection accuracy of the sensor is improved.

The inner part-spherical cover 62 and an outer partially spherical-shaped cover 63 of the real施例constitutes the partial spherical cover of the present invention, 6-component sensor 60 embodiment constitutes the sensor of the present invention.

  Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.

  1 to 7 show an embodiment of the present invention. FIG. 1 is a front view of a legged mobile robot, FIG. 2 is a right side view of the legged mobile robot, and FIG. 3 is a line 3-3 in FIG. 4 is a sectional view taken along the line 4-4 in FIG. 3, FIG. 5 is a perspective view of the lower leg portion and the foot portion, and FIG. 6 is an explanation of the action of pitching the foot portion. FIGS. 7A and 7B are explanatory diagrams of the rolling action of the foot.

  As shown in FIGS. 1 and 2, the legged mobile robot R capable of walking on two legs is provided with a trunk 11, a head 12, a left arm 13L, a right arm 13R, a left leg 14L, and a right leg 14R. An electrical component box 15 containing electrical components is carried on the back of the machine. Each of the left arm 13L and the right arm 13R is composed of an upper arm part 16, a lower arm part 17, and a hand part 18. The body 11 and the upper arm part 16 are connected by a shoulder joint 19, and the upper arm part 16 and the lower arm part are connected to each other. 17 is connected by an elbow joint 20, the lower arm portion 17 and the hand portion 18 are connected by a wrist joint 21, and in the middle of the upper arm portion 16 in the longitudinal direction, the lower half of the upper arm portion 16 is lower than the upper half portion. A brachial joint 22 for twisting the part is provided. Each of the left leg 14L and the right leg 14R includes an upper leg portion 23, a lower leg portion 24, and a foot portion 25. The body 11 and the upper leg portion 23 are connected by a hip joint 26. The lower leg 24 is connected by a knee joint 27, and the lower leg 24 and the foot 25 are connected by an ankle joint 28. Further, the body 11 and the head 12 are connected by a neck joint 29. Note that only the position of each joint is indicated by a broken-line circle.

  Next, the structure of the right leg 14R of the robot R will be described with reference to FIGS. Note that the left leg 14L has the same structure as the right leg 14R and is mirror-symmetrical, and therefore, redundant description thereof is omitted.

  The upper leg portion 23 and the lower leg portion 24 are connected by a knee joint 27 having an axis L, and are driven via a belt transmission means 31 and a speed reducer 32 by a drive source (not shown). The lower leg portion 24 includes a lower leg link 33 that constitutes the skeleton. A pitching motor 34 having an output shaft 34 a disposed in the left-right axis Ly direction is supported on an upper end portion of the lower leg link 33, and an intermediate portion of the lower leg link 33 is supported. A rolling motor 35 in which the output shaft 35a is arranged in the left-right axis Ly direction is supported.

  On the left and right axis Ly, the pitching shaft portion 36 is rotatably supported by the lower end of the lower leg link 33 via a pair of cross roller bearings 38 and 38 (see FIG. 3). A drive pulley 39 provided on the output shaft 34 a of the pitching motor 34 and a driven pulley 40 disposed on the left and right axis line Ly are connected by an endless belt 41. The driving pulley 39, the driven pulley 40 and the endless belt 41 constitute a pitching belt transmission means 42. The driven pulley 40 and the pitching shaft portion 36 are connected by a pitching speed reducer 43 made of a known harmonic speed reducer (trade name). The harmonic speed reducer decelerates the rotation of the input member and outputs it to an output member arranged on the same axis, and can be replaced with a planetary gear type speed reducer.

  A rolling shaft portion 44 that extends in a direction orthogonal to the pitching shaft portion 36 (front-rear axis Lx) is integrally formed (see FIG. 4). A cylindrical rolling member 46 is supported on the outer periphery of the rolling shaft portion 44 via a pair of cross roller bearings 47 and 47, and the foot portion 25 is fixed to the rolling member 46.

  A driven pulley 52 fixed to the shaft end of a driving bevel gear shaft 51 supported relatively rotatably inside the pitching shaft portion 36 and a driving pulley 53 fixed to an output shaft 35 a of the rolling motor 35 are connected by an endless belt 54. The drive pulley 53, the driven pulley 52, and the endless belt 54 constitute a rolling belt transmission means 55. A driven bevel gear 57 provided at the shaft end of a driven bevel gear shaft 56 supported so as to be relatively rotatable within a rolling shaft portion 44 formed integrally with the pitching shaft portion 36 is provided at the shaft end of the drive bevel gear shaft 51. Engage with the drive bevel gear 58. The shaft end of the driven bevel gear shaft 56 and the rolling member 46 are connected by a rolling reduction gear 59 made of a harmonic reduction gear. On the upper surface of the center of the foot 25, 6 component forces (a load in three orthogonal directions and a moment about the three axes) acting on the foot 25 are detected in order to make the robot R walk on two legs. A component force sensor 60 is provided, and an amplifier 64 of the six component force sensor 60 is provided on the rear upper surface of the foot 25.

  The rolling mechanism 61 for rolling the foot 25 with respect to the pitching shaft 36 includes the rolling shaft 44, the rolling member 46, the drive bevel gear shaft 51, the drive bevel gear 58, the driven bevel gear shaft 56, and the driven bevel gear 57. And a rolling belt transmission means 55.

  As apparent from FIG. 5 to FIG. 7, the ankle joint 28 that supports the foot portion 25 so as to be pitchable and rollable with respect to the lower leg portion 24 is a concentric spherical surface centering on the intersection of the longitudinal axis Lx and the lateral axis Ly. The inner part spherical cover 62 and the outer part spherical cover 63 that constitute a part of the outer part spherical cover 63 are provided. The inner partial spherical cover 62 is fixed to the rolling member 46, while the outer partial spherical cover 63 is fixed to the pitching shaft portion 36. Therefore, when the foot portion 25 is pitched around the left-right axis Ly, the inner portion spherical cover 62 and the outer portion spherical cover 63 are integrally pitched, and when the foot portion 25 is rolled about the front-rear axis Lx, Only the inner partial spherical cover 62 rolls relative to the partial spherical cover 63. Even if the outer part spherical cover 63 and the inner part spherical cover 62 are relatively rotated, the inner part spherical cover 62 has a substantially rotationally symmetric shape about the longitudinal axis Lx. No step or gap occurs in the shape of the partial spherical surface constituted by 63 and the inner partial spherical cover 62. A concave spherical surface 33 a is formed at the lower end of the lower leg link 33, and a minute and uniform gap α is formed between the concave spherical surface 33 a and the outer peripheral surfaces of the outer partial spherical cover 63 and the inner partial spherical cover 62. .

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  When the pitching motor 34 is driven to pitch the foot 25 connected to the lower end of the lower leg 24 of the robot R via the ankle joint 28 around the left and right axis Ly, the rotation of the output shaft 34a is rotated by the pitching belt transmission means. 42 is transmitted to the pitching speed reducer 43 via the drive pulley 39, the endless belt 41 and the driven pulley 40, and the pitching speed reducer 43 decelerates the input rotation and outputs it to the pitching shaft portion 36. When the pitching shaft portion 36 rotates around the left and right axis line Ly together with the rolling shaft portion 44 integral therewith, the foot portion 25 supported by the rolling shaft portion 44 via the rolling member 46 pitches around the left and right axis line Ly. Even when the pitching shaft portion 36 rotates in this way, the drive bevel gear shaft 51 of the rolling mechanism 61 is disposed coaxially within the pitching shaft portion 36 and is relatively rotatable. By making it possible, it is possible to prevent the foot 25 from rolling in a delusion.

  When the rolling motor 35 is driven to roll the foot 25 around the front and rear axis Lx, the rotation of the output shaft 35a is driven via the driving pulley 53, the endless belt 54 and the driven pulley 52 of the rolling belt transmission means 55. The rotation of the drive bevel gear shaft 51 is transmitted through the drive bevel gear 58, the driven bevel gear 57 and the driven bevel gear shaft 56 and then transmitted to the rolling member 46 through the rolling reduction gear 59. Then, the foot 25 integrated with the rolling member 46 is rolled. In this way, the rolling mechanism 61 is supported on the pitching shaft portion 36 and pitched integrally with the foot portion 25, and the rolling mechanism 61 is operated alone to roll the foot portion 25 with respect to the pitching shaft portion 36. Pitching and rolling do not interfere with each other or cross each other, and the control of pitching and rolling of the foot 25 is simplified.

  Since the pitching motor 34 and the rolling motor 35 are supported by the lower leg portion 24 above the ankle joint 28, the positions of the heavy weight pitching motor 34 and the rolling motor 35 approach the knee joint 27. As a result, the moment of inertia of the lower leg 24 around the knee joint 27 can be reduced, and the load of the drive source that drives the knee joint 27 can be reduced. In addition, since the positions of the pitching motor 34 and the rolling motor 35 are far from the six component force sensor 60 provided on the foot 25, the six component force sensor 60 is affected by the noise of the pitching motor 34 and the rolling motor 35. It becomes difficult to improve the detection accuracy.

  Further, with the above arrangement of the pitching motor 34 and the rolling motor 35, the positions of the pitching shaft portion 36 and the rolling shaft portion 44 are lowered, and compliance control of the ankle joint 28 can be realized with a smaller control amount. Thereby, it is possible to promptly respond to unexpected irregularities and inclinations of the floor surface and enable stable walking.

  Further, when the foot portion 25 is pitched, the inner partial spherical cover 62 and the outer partial spherical cover 63 centering on the intersection of the left and right axis Ly and the front and rear axis Lx rotate together, so both the covers 62 and 63 and the lower leg link 33 are rotated. The gap [alpha] between the lower end and the concave spherical surface 33a is kept constant, and foreign matter can be prevented from being caught. Further, when the foot 25 is rolled, the inner partial spherical cover 62 rotates relative to the outer partial spherical cover 63, but the gap α does not change, so that it is possible to prevent foreign matter from being caught. it can. In addition, since the gap α does not change, the inner partial spherical cover 62 and the outer partial spherical cover 63 do not easily interfere with the lower leg link 33, and the movable range of the ankle joint 28 can be expanded.

  As mentioned above, although the Example of this invention was explained in full detail, this invention can perform a various design change in the range which does not deviate from the summary.

For example, in real施例but detects the load applied to the foot 25 in the 6 component force sensor 60 can be replaced by a sensor that can detect three component forces to 5 component force.

Front view of legged mobile robot Right side view of legged mobile robot 2 is an enlarged sectional view taken along line 3-3 in FIG. 2 (sectional view taken along line 3-3 in FIG. 4). Sectional view taken along line 4-4 in FIG. Perspective view of lower leg and foot Action diagram of foot pitching Illustration of foot rolling action

23 the upper leg portion 24 lower leg 25 foot portion 27 knee joint 28 ankle joint 33 lower leg link
3 5 Rolling for motor 35a output shaft 36 the pitching shaft 43 pitching speed reducer 44 roll shaft 46 rolling member 55 Rolling belt transmission means 57 driven bevel gear 58 driven bevel gear 59 reduction gears 60 6 component force sensor 61 rolling for rolling Mechanism 62 Inner part spherical cover 63 Outer part spherical cover Ly Left and right axis Lx Front and rear axis α Clearance

Claims (5)

Lower leg via the knee joint (27) at the lower end of the upper leg portion (23) with connecting (24), connecting the foot to the lower end of the lower leg (24) and (25) through the ankle joint (28) The ankle joint (28) is a leg type that supports the foot (25) with respect to the lower leg (24) so that it can be pitched around the left and right axis (Ly) and can be rolled around the front and rear axis (Lx). A leg structure of a mobile robot,
A rolling mechanism (61) for supporting the foot (25) on the pitching shaft (36) in a freely rolling manner,
A rolling shaft (44) fixed so as to be orthogonal to the pitching shaft (36);
A rolling member (46) fixed integrally to the foot (25) and rotatably supported on the outer periphery of the rolling shaft (44);
A drive bevel gear (58) disposed coaxially within the pitching shaft (36);
Rolling belt transmission means (55) for transmitting the rotation of the output shaft (35a) of the rolling motor (35) arranged in the left-right axis (Ly) direction to the drive bevel gear (58);
A legged mobile robot comprising: a driven bevel gear (57) which is coaxially disposed in the rolling shaft portion (44) and meshes with the drive bevel gear (58) and connected to the rolling member (46). Leg structure. Pi etching belt transmission means (42) and the pitching shaft (36) pitching speed reducer (43) disposed between the driven bevel gear (57) and rolling members (46) rolling speed reducer between the (59) The leg structure of the legged mobile robot according to claim 1 , wherein the leg structure is arranged. Outside it is covered with a partial spherical cover (62, 63) of the B-ring member (46), the lower leg lower end portions spherical cover (62, 63) and of the lower leg link (33) which constitutes the backbone of (24) and characterized by forming a predetermined gap (alpha) between, claim 1 or leg structures of a legged mobile robot according to claim 2. Parts partial spherical cover (62, 63) is characterized by having a center on the pitching shaft (36) or on a rolling shaft portion (44), the leg structure of the legged mobile robot according to claim 3. The legged mobile robot according to any one of claims 1 to 4 , wherein a sensor (60) for detecting a load applied to the foot (25) is provided on the foot (25). Leg structure.

Images