JP2005238407A - Walking robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain consumption energy required when changing a direction of a walking robot in the walking robot. <P>SOLUTION: This walking robot walks by driving of legs, by having at least two legs composed of a plurality of link members and a joint part for connecting the respective link members. A leg tip part 24 is arranged on the tip of the legs. The leg tip part 24 has a first member 66 grounded on a walking road surface, and a second member 64 ungrounded on the walking road surface. In the height direction of the walking robot, the first member 66 is arranged on the walking road surface side more than the second member 64, and the first member 66 relatively freely rotate to the second member 64 with the height direction of the walking robot as the rotation axis. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a walking robot having at least two legs and capable of walking motion with the legs.

  Conventionally, there are many leg structures of walking robots that are grounded as a group of rigid bodies, and what can be seen by people as the shape of walking robots is limited to this structure. However, some of the experimentally proposed ones have legs divided into a plurality of parts and can move relative to each other. For example, a technique of providing a joint imitating a human toe in a leg portion of a walking robot has been shown (for example, see Non-Patent Document 1). In the walking robot having this leg structure, the output of the motor housed in the body is connected to the toe joint via a flexible wire to drive the toe.

  Moreover, about another leg part structure, the leg part structure which can change the contact area of a leg part is disclosed (for example, refer patent document 1). In a walking robot having this leg structure, the contact area of the leg is changed according to the place of walking in order to improve the stability of the walking robot. However, a ground contact area is changed by transmitting a driving force of a motor having a small capacity to a leg through a reduction gear having a large reduction ratio. Therefore, it takes a long time to change the contact area of the legs.

In order to change the direction of the walking robot, a leg joint that moves passively at the leg of the walking robot is provided at the tip of the leg, and when the leg is driven, the joint bends and the tiptoe stands on the shape. A technique to be realized is disclosed (for example, see Patent Document 2). In a walking robot having this leg structure, since the time required for the change is less than the conventional direction change by the stepping motion of the walking robot, the energy consumption required for the direction change is also reduced. Is sung.
Furusho, Sano “Sensor-Based Control of a Nine-Link Biped”, The International Journal of Robotics Research, (United Stats of America), Massachusetts Institute of Technology, April 1990, vol.9, No.2, p.83- 98 JP-A-5-318337 JP-A-4-122586

  For any request to the walking robot, for example, when it is necessary to change the direction of the walking robot in order to avoid an obstacle in front of the walking robot, if the direction is changed by causing the walking robot to step on In addition, the time required for this increases, and since it is necessary to drive many joints in the entire walking robot, the energy consumption required for changing the direction also increases.

  In view of the above problems, an object of the present invention is to suppress energy consumption required for changing the direction of a walking robot in a walking robot.

  In order to solve the above-described problems, the present invention has at least two legs each composed of a plurality of link members and joint portions connecting the link members, and walks by driving the legs. In the walking robot, a leg tip portion is provided at a tip of the leg, and the leg tip portion includes a first member that contacts the walking road surface and a second member that does not contact the walking road surface. In the height direction, the first member is provided closer to the walking road surface than the second member, and the first member is rotatable relative to the second member with the height direction of the walking robot as a rotation axis. And

  That is, in the leg that supports the weight of the walking robot, the leg tip portion that contacts the walking road surface is constituted by at least two members, the first member and the second member. This leg tip corresponds to a part from the ankle to the tip of the toe if compared with a human. The feature of the present invention is that the first member that contacts the walking road surface can rotate relative to the second member that does not contact the walking road surface. Here, the rotation is performed with the height direction of the walking robot as a rotation axis. The height direction of the walking robot means the leg of the walking robot that connects the leg tip portion to the leg tip portion, and the main body of the walking robot. For example, when the walking robot is on a horizontal walking road surface, the direction is perpendicular to the walking road surface.

  Thus, the direction of the walking robot is changed by allowing the first member that contacts the walking road surface to rotate relative to the second member that does not contact the walking road surface. At this time, the energy consumption required for changing the direction of the walking robot is greatly influenced by the frictional force on the sliding surface where the direction is changed. In the walking robot according to the present invention, since relative rotation is performed between the first member and the second member, in other words, regardless of the frictional force between the walking road surface and the first member, in other words, the road surface of the walking road surface Regardless of the situation, the direction of the walking robot can be changed by resisting the substantially constant frictional force between the first member and the second member. As a result, the energy consumption required for changing the direction of the walking robot can be made substantially constant regardless of the road surface condition of the walking road surface, thereby suppressing an increase in energy consumption when changing the direction of the walking robot.

  Depending on the road surface condition of the walking road surface, the frictional force between the first member and the walking road surface may be lower than the frictional force between the first member and the second member. In such a case, the direction of the walking robot is changed by performing relative rotation between the first member and the walking road surface.

  Here, in the above-described walking robot, a friction control member is provided between the first member and the second member so that a friction force between the first member and the second member is a predetermined friction force, The relative rotation between the first member and the second member may be performed via the friction control member. The predetermined frictional force is a frictional force that can suppress energy consumption required for changing the direction of the walking robot, and is preferably as low as possible in principle. Thus, by interposing the friction control member between the first member and the second member, the frictional force when changing the direction of the walking robot is reduced as much as possible as the predetermined frictional force. It becomes possible to control the energy consumption required for the direction change to a target value.

  Then, in the above-described walking robot, with the first member in contact with the walking road surface, relative rotation between the first member and the second member is performed to rotate and change the direction of the walking robot. You may make it further provide a walking robot direction change means. For example, by applying a rotational force to the leg of the walking robot, that is, the second member provided on the leg tip, by the driving force from the knee joint or the hip joint, which is the joint of the leg of the walking robot, The second member rotates relative to the second member, thereby changing the direction of the walking robot.

Further, in the above-described walking robot, the walking robot direction changing means in each of the first members in a state where each of the first members is in contact with the walking road surface in at least two legs having the leg tip portion. By applying a driving force to the legs in the same rotational direction along one virtual circle determined by the load center, the first member and the second member are relatively rotated, The direction of the walking robot may be changed.

  That is, when the walking robot is supported by at least two legs and the first member is in contact with the walking road surface, when the driving force is applied to the legs in the above-described direction, The relative position between the first member and the walking road surface is not changed by the frictional force between the walking road surface and the first member and the second member are relatively rotated by the reaction force of the driving force. Thereby, the direction of the walking robot is changed. One virtual circle is a virtual circle including the center of the load applied to the first member of each leg of the walking robot. By applying a driving force to the legs in the direction along this virtual circle, it is possible to suppress as much as possible that the center of gravity of the walking robot greatly fluctuates and the posture becomes unstable when the direction of the walking robot is changed. Can do.

  The walking robot described above may further include a biasing unit that biases the first member in a direction that prevents relative rotation between the first member and the second member. When the relative rotation with the second member is performed, the urging force applied to the first member by the urging means decreases or the urging force applied to the first member by the urging means is released. You may do it.

  That is, when there is no need to perform relative rotation between the first member and the second member, such as when the walking robot walks or stops, the biasing means biases the first member by It is possible to prevent relative rotation and thereby prevent the posture of the walking robot from becoming unstable. On the other hand, when the relative rotation of the first member and the second member is performed, the relative rotation between the first member and the second member is reduced by reducing or releasing the biasing by the biasing means. It becomes possible to carry out more smoothly. In addition to using an elastic member such as a spring as the urging means, the urging force may be controlled by using a piston driven by air pressure and controlling the air pressure supplied to the piston.

  Furthermore, the walking robot described above may further include a braking unit that controls prohibition of relative rotation between the first member and the second member or cancellation of the prohibition. Thus, the relative rotation of the first member and the second member is controlled by the walking robot having the braking means. For example, when the walking robot is walking or stationary, the braking means prohibits relative rotation between the first member and the second member, thereby suppressing the posture of the walking robot from becoming unstable. . On the other hand, when the direction of the walking robot is changed, the prohibition of relative rotation between the first member and the second member is canceled by the braking means.

  Further, in the leg tip portion, the third member different from the first member is also grounded with the walking road surface, and the third member is relative to the second member around the rotation axis. In the case where the rotation is not performed, the braking means transmits a relative rotational force between the first member and the second member, and cancels the ground contact state of the third member with the walking road surface. Thus, the relative rotation between the first member and the second member can be performed, the transmission of the relative rotational force between the first member and the second member is interrupted, and the first member You may make it prohibit the relative rotation of this 1st member and this 2nd member by grounding one member and the 3rd member on the said walking road surface.

That is, the relative rotation between the first member and the second member is prohibited by controlling the transmission of the relative rotational force generated between the first member and the second member like a clutch. Or the prohibition is lifted. Here, when the relative rotation between the first member and the second member is prohibited, the posture of the walking robot is more stable because the first member and the third member are in contact with the walking road surface. On the other hand, when the rotation is possible, the sliding area between the first member and the second member is reduced by eliminating the ground contact state between the third member and the walking road surface. By reducing the area or the sliding area between the first member and the walking road surface, it is possible to reduce the frictional force generated during the rotation.

  According to the present invention, in a walking robot, it is possible to suppress energy consumption required when changing the direction of the walking robot.

  Here, an embodiment of a walking robot according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic skeleton diagram of the lower half of a walking robot 1 having two legs suitable for applying the present invention. In FIG. 1, a walking robot 1 has six joints on the left and right legs. The six joints are, in order from the top, a leg rotation joint 10, a hip joint pitch-direction joint 12, a roll-direction joint 14, a knee joint pitch-direction joint 16, and an ankle joint pitch direction. The joint 18 and the joint 20 in the same roll direction are provided, and a leg tip portion 24 is provided at the lower part thereof.

  A waist plate link 26 corresponding to the pelvis of the human body is prepared at the uppermost part of the lower body. The waist plate link 26 is equipped with a power source and an amplifier (amplifier) necessary for joint control, a pressure accumulation tank 90 related to the present invention, and the like. Here, the pressure accumulation tank 90 is a tank for storing high-pressure air that becomes a power source of a piston 52 in the joint 50 described later. The supply of high-pressure air stored in the pressure accumulation tank 90 will be described later.

  The right leg and the left leg are mirror images and have a symmetrical shape. The letters L and R next to each number mean left and right, respectively, and have no other meaning. In the following description, for example, when it is described as joint 10L / R, it represents joints 10L and 10R on both the left and right sides, and for example, when it is expressed as joint 10 and when it is expressed as joint 10L / R, There is no difference in meaning. The hip joint is composed of three joints 10, 12, and 14 as shown in the figure, a thigh link 30 is prepared for coupling the hip joint and the knee joint, and the ankle joint is also shown as two joints 18 and 20 as shown in the figure. A snelink 32 is prepared for the connection between the ankle joint and the knee joint.

  Here, the leg tips 24L / R connected to the ankle joints are provided with joints 50R and 50L related to an operation for changing the direction of the walking robot 1 according to the present invention (hereinafter referred to as “direction changing operation”). It has been. The joint 50L / R is a type of joint that enables linear motion and rotational motion as described later. Also in the joint 50L / R, joints of the same type are provided in the leg portions of both legs due to the mirror image.

  Here, FIG. 2 shows the structure of the joint 50 involved in the direction changing operation in detail. The leg tip portion 24 is provided with a cylinder 54 that accommodates a piston 52 that is driven by the air pressure of the compressed air supplied from the pressure accumulation tank 90 so as to be movable in a certain direction. The cylinder 54 has two different diameters and forms a pressure chamber 56 for introducing air pressure. Further, the piston 52 is prevented from rotating relative to the cylinder 54 by a detent pin 58. As a result, the piston 52 is moved by air pressure only in the vertical direction in FIG. In addition, when the following description shows an up-down direction and a direction, it means the up-down direction in each figure. Further, the upper space 60 of the piston 52 is open to the atmosphere, and as a result, a desired vertical movement can be realized with a small consumption of compressed air.

Here, a rotation shaft 62 is disposed in the center of the piston 52 so as to penetrate vertically.
The axial direction of the rotary shaft 62 is the vertical direction in FIG. 2 and the same direction as the height direction of the walking robot 1. A first member 66 that directly contacts the walking road surface is supported on the lower side of the rotation shaft 62 so as to be rotatable around the rotation shaft 62. Hereinafter, the piston 52 is also referred to as a second member 52. In addition, a third member 64 that contacts the walking road surface independently of the first member 66 is provided at the tip of the leg tip portion 24. The third member 64 is fixed to the leg tip portion 24 side. Here, when the second member (piston) 52 is in the illustrated position, that is, when the second member (piston) 52 is in the uppermost position, the lower surface of the first member 66 and the lower surface of the third member 64 are substantially the same. Are designed to have the same surface.

  In this way, the second member (piston) 52 moves up and down in the cylinder 54, so that the first member 66 moves in a direction protruding from the third member 64. As a result, when the second member (piston) 52 moves downward, only the first member 66 is in contact with the walking road surface, and the third member 64 is not in contact with the walking road surface. As a result, a step δ (δ shown in FIG. 5) is generated between the first member 66 and the third member 64, and the step δ appears as a height change amount of the walking robot 1. In the state shown in FIG. 2, the step δ is zero.

  The first member 66 and the third member 64 have relatively soft elastic members 65 and 67 attached to the grounding surface with an adhesive so as to be well adapted to the road surface. Further, between the first member 66 and the second member (piston) 52, a doughnut-shaped first resin plate 70 having a low friction coefficient is mounted for the purpose of improving the slip between them. At the same time, a second resin plate 72 having a relatively high coefficient of friction is mounted between the first member 66 and the third member 64.

  In the upper part of the rotating shaft 62, a return spring 80 is provided to quickly return to the uppermost position shown in the figure when the air pressure is removed after the second member (piston) 52 is lowered by the air pressure from the pressure accumulating tank 90. Is prepared. It is assumed that when the piston is returned to the uppermost position shown in the figure by the return spring 80, the second resin plate 72 serves as a stopper and the first resin plate 70 is unloaded. That is, the thickness of the first resin plate 70 is slightly thinner than the thickness of the second resin plate 72. The contact relationship between the first resin plate 70, the second resin plate 72, the second member (piston) 52, and the first member 66 will be described later.

  2 is a motor that drives the ankle roll joint 20L / R shown in FIG. 1, and 84 shown in FIG. 2 is a portion that houses a reduction gear that decelerates the output of the motor 82 to increase its power. 2 is a cover for accommodating the pitch joint 18L / R of the ankle joint.

  Next, FIG. 3 shows an air pressure control circuit that controls the air pressure supplied to the second member (piston) 52. High pressure air is injected into the accumulator tank 90 via a check valve 91, and the air pressure is reduced to a desired level by the pressure reducing valve 92. Then, by opening the electromagnetic valve 94, the high pressure air is guided to the pressure chamber 56L / R so as to push down the second member (piston) 52L / R. When the solenoid valve 94 is energized, the circuit configuration on the left side shown in FIG. 3 is used to guide the output of the pressure reducing valve 92 to the pressure chamber 56L / R. The pressure chamber 56 communicates with the atmosphere. Such a solenoid valve 94 is normally used and is widely commercially available. The illustrated solenoid valve is sold as a pilot valve, and is a solenoid valve that consumes only 0.5 W when energized.

FIG. 4 shows a schematic configuration of a control device including the above-described electromagnetic valve 94 and a motor that is an actuator of a joint of the walking robot 1. A CPU (Central Processing Unit) 100 accesses a memory 102 that stores gait data for determining the leg motion of the walking robot 1, reads gait data, and further reads the current joint angle value and joint angular velocity value of each joint. . Thereafter, the motor torque to be exhibited by the motor 106 is calculated, and this motor torque is sent to the amplifier (amplifier) 104 as a command value. The amplifier 104 calculates and determines a current value from the command value and drives the motor 106. When the motor 106 is driven, the joint changes its angle, and the angle is read by an appropriate sensor (angle meter) 108 and sent to the CPU 100 as angle information.

  In FIG. 4, there are twelve amplifiers 104, motors 106, and goniometers 108 according to the number of joints in the present embodiment, that is, twelve each. However, in the drawing, only three are provided to simplify the explanation. It is drawn schematically. In this embodiment, the gait data format is stored in the form of time series data of joint angles calculated in advance. One example thereof is disclosed in detail in FIG. 6 of Japanese Patent Laid-Open No. 4-201187, for example.

  Here, based on FIG. 5, the first member 66, the third member 64, the first resin plate 70, and the second resin plate 72 associated with the movement of the second member (piston) 52 in the direction changing operation in the walking robot 1. This will be described together with the contact relationship. FIG. 5A is a view showing the contact relationship when the second member (piston) 52 is at the uppermost position (position shown in FIG. 2), and FIG. 5B is the air pressure from the accumulator tank 90. It is a figure which shows this contact relationship when the 2nd member (piston) 52 exists in the lowest position by this.

  As shown in FIG. 5A, when the second member (piston) 52 is in the uppermost position, as described above, the first member 66 is in contact with the second resin plate 72, and the first member. The lower surface of 66 and the lower surface of the third member 64 are substantially in the same plane. In this state, since the first member 66 is in contact with the second resin plate 72 having a relatively high friction coefficient, the rotation of the first member 66 around the rotation shaft 62 is suppressed. On the other hand, the first member 66 is not in contact with the first resin plate 70, and the second member (piston) 52 is a leg tip portion where the third member 64 is provided via a detent pin 58. 24 and an integral structure. Therefore, relative rotation cannot occur between the first member 66 and the second member (piston) 52. Therefore, the contact state as shown in FIG. 5A is a suitable state when walking or when the posture stability of the walking robot 1 is further required.

  5B, when the second member (piston) 52 is in the lowest position, the second member (piston) 52 pushes the first member 66 through the first resin plate 70. It will be in the state. At this time, as described above, the first member 66 is in contact with the walking road surface, and the third member 64 is not in contact with the walking road surface. As a result, a step δ is generated between the first member 66 and the third member 64. In this state, since the first member 66 is in contact with the first resin plate 70 having a relatively low coefficient of friction, when a rotational force is applied to the first member 66 or the second member (piston) 52, the first member 66 A relative rotation occurs between the member 66 and the second member (piston).

  In other words, since the third member 64 is not in contact with the walking road surface, the first resin plate 70 is determined by the frictional force between the walking road surface and the first member 66, more precisely, the elastic material 67 and the walking road surface. When the frictional force between the first member 66 and the first member 66 is small, when a rotational force is applied to the first member 66 or the second member (piston) 52, the first resin plate 70 is interposed, A relative rotation occurs between the first member 66 and the second member (piston) 52. The direction of the walking robot 1 is changed by the relative rotation.

  In addition, when the friction force between the walking road surface and the first member 66, more precisely, the elastic material 67 and the walking road surface is smaller than the friction force between the first resin plate 70 and the first member 66, When a rotational force is applied to the first member 66 or the second member (piston) 52, the first member 66 rotates relative to the walking road surface, and as a result, the direction of the walking robot 1 is changed. In this case, since the third member 64 is not in contact with the walking road surface, the frictional force to be resisted when the direction of the walking robot 1 is changed is relatively small.

  The walking robot 1 having the joint 50 configured as described above controls the position of the second member (piston) 52 by controlling the air pressure supplied from the pressure accumulation tank 90 to the second member (piston) 52. . As a result, the relative rotation between the first member 66 and the second member (piston) 52 is prohibited, or the prohibition of the prohibition is released, whereby the direction change operation of the walking robot 1 is performed. . Therefore, in this embodiment, controlling the energization to the electromagnetic valve 94 to control the position of the second member (piston) 52 corresponds to the braking means according to the present invention.

  Here, the control of the legs for applying the rotational force to the first member 66 or the second member (piston) 52 for the direction changing operation of the walking robot 1 will be described below. As described above, the following control is performed when the second member (piston) 52 is in the lowest position, that is, the first member 66 is rotated relative to the second member (piston) 52 by the braking means. This is done when the ban is lifted.

  FIG. 6 shows the basic principle of the direction changing operation of the walking robot 1. FIG. 6A shows how to move the leg as viewed from the top of the walking robot 1. In FIG. 6A, the center of gravity of the walking robot 1 coincides with the coordinate origin O in the figure. At this time, the walking robot 1 is supplied with high-pressure air to the pressure chamber 56L / R, and the second member (piston) 52L / R moves downward, so that the first leg portion 24L / R Only one member 66L / R is in contact with the walking road surface. The position of the leg tip portion 24L / R at this time is indicated by a bold line. In addition, the center points of distributed loads acting on the leg tip portions 24L / R are PL and PR. The case where the leg joints other than the joint 50 are adjusted so that the center points PL and PR are in the center of the first members 66L / R (indicated by dotted circles) of the two leg tip portions 24L / R. Assuming this case, the direction changing operation of the walking robot 1 will be described as an example.

  In the state shown in FIG. 6A, the legs excluding the joint 50 are used to rotate the left and right legs counterclockwise in a state where the direction of the leg tips 24L / R is fixed so as not to change with respect to the body of the walking robot 1. Give driving force to the joint. However, since friction exists between the first member 66L / R and the walking road surface, this driving force causes the walking robot 1 to rotate the earth counterclockwise. On the other hand, due to Newton's law of action / reaction, the walking robot 1 receives a clockwise rotational force from the earth. Since the inertia moment of the earth is overwhelmingly larger than that of the walking robot 1, as a result, the walking robot 1 receives a rotational force that rotates in a clockwise direction. Here, when the frictional force between the first member 66L / R and the first resin plate 70L / R is smaller than the frictional force between the first member 66 and the walking road surface, the rotational force causes the first The member 66L / R and the second member (piston) 52L / R rotate relatively, and as a result, the walking robot 1 changes its direction in the clockwise direction.

  Here, the state of the direction changing operation of the walking robot 1 is shown in FIG. FIG. 6B shows a state where the walking robot 1 is viewed from coordinates fixed on the earth. The state of both legs of the walking robot 1 is such that the driving force is applied to the left and right legs in the state shown in FIG. 6 (a) to move the legs along the virtual circle TC shown in FIGS. 6 (a) and (b). Provided by leg joints except 50. This virtual circle TC is defined as a circle passing through the center points PL and PR. In the present embodiment, the center of the virtual circle coincides with the coordinate origin O.

Then, as the driving force is applied to the left and right legs, the direction of the walking robot 1 is changed to the clockwise direction as shown in FIG. 6B as described above. In this embodiment, when the direction of the walking robot 1 coincides with the tangential direction of the virtual circle TC in PL and PR, the direction changing operation of the walking robot 1 ends. As a result, the walking robot 1 turns from the state of FIG. 6A in the clockwise direction by θR (rotation angle about the coordinate origin O). At this time, both legs of the walking robot also rotate around the points PL and PR by θS (the rotation angles about the load centers PL and PR of both legs of the walking robot 1), but θR and θS are geometrically related. Are equal to each other.

  Here, when the two planes rotate and slide relative to each other while receiving a constant weight of the walking robot 1, the rotational resistance increases as the ground contact area increases. Therefore, by projecting the first member 66L / R by air pressure, the rotational resistance during the rotational operation is reduced, and then the center of the first member 66L / R is the virtual circle TC while the hip joint 10L / R is fixed. By driving the joints other than the joint 50 so as to rotate in the counterclockwise direction, the direction changing operation of the walking robot 1 can be executed while maintaining a stable posture with a small rotational resistance.

  Further, if the knee joint is desirably straightened and fixed and the direction changing operation is performed, that is, the joints 10L / R and the joint 16L / R are operated with the constant joint angle maintained, the number of the joints is less. The direction can be changed with energy.

  Further, the joint 50 of the leg tip portion 24 of the present embodiment has a low friction coefficient in order to realize a relative rotational movement with a small amount of friction between the second member (piston) 52 and the first member 66. One resin plate 70 is interposed. Therefore, the second member (piston) 52 and the first member are independent of the friction coefficient between the walking road surface and the first member 66 even on a walking road surface such as an asphalt road surface having a high friction coefficient on the walking road surface. The frictional force between 66 and 66 becomes a resistance force during the direction changing operation. Therefore, regardless of the frictional force between the walking road surface and the first member 66, the direction changing operation can be executed with constant energy consumption, and an increase in the energy consumption can be suppressed.

  This means that the walking robot 1 performs the direction changing operation without energizing the solenoid valve 94 (without consuming compressed air) when the walking road surface is slippery like plastic. Is not to deny. Such a selection can be easily performed only by giving the walking robot 1 a knowledge base about the environment.

  Further, during the direction changing operation, the joint braking device disclosed by the present applicant in Japanese Patent Application No. 2002-205845 is used to brake the drive motors of the joints 10 and 16 in the present embodiment. If the power supply is stopped, the direction changing operation can be executed with less energy consumption.

  A second embodiment of the walking robot 1 according to the present invention will be described with reference to FIG. In this embodiment, a leg tip portion 540 is provided instead of the leg tip portion 24 shown in FIG. 2, and a joint 500 involved in the direction changing operation is provided on the leg tip portion 540 instead of the joint 50 shown in FIG. Provided. Here, FIG. 7 shows the structure of the joint 500 involved in the direction changing operation in detail. In addition, the leg tip part 540 is a part which receives the weight of the walking robot 1 and contacts the walking road surface in the same manner as the leg tip part 24 described above. The walking robot 1 according to the present embodiment is the same as the walking robot 1 shown in FIG. 1 except for the leg tip 540 and the joint 500, but the leg tip 540 has the piston 52 described above. Therefore, the pressure accumulation tank 90 and the air pressure control circuit shown in FIG. 3 are not provided.

  The leg tip portion 540 includes a first member 501 and a second member 502. The first member 501 contacts the walking road surface via the elastic member 505. On the other hand, the second member 502 is positioned above the first member 501 in the height direction of the walking robot, and does not contact the walking road surface. A resin plate 504 having a doughnut-like shape and a low friction coefficient is provided between the first member 501 and the second member 502 for the purpose of improving the slip between them. A rotation shaft 503 (described later) passes through the central hole of the resin plate 504.

  Here, the rotating shaft 503 is disposed so as to penetrate the first member 501 and the second member 502 in the vertical direction. The axial direction of the rotating shaft 503 is the vertical direction in FIG. 7 and the same direction as the height direction of the walking robot 1. And the 1st member 501 is being fixed to the lower side of the rotating shaft 503 without the clearance gap between the rotating shaft 503 and serrations. On the other hand, the second member 502 is provided on the upper side of the rotation shaft 503, but the rotation shaft 503 and the second member 502 are loosely fitted. Accordingly, the first member 501 can rotate relative to the second member 502. A winding spring 503 is provided at a portion above the second member 502 of the rotating shaft 503, one end of which is fixed to the rotating shaft 503 and wound around the axis of the rotating shaft 503. The other end of the winding spring 503 is attached to the second member 502.

  Further, there is a portion where the resin plate 504 is not provided between the first member 501 and the second member 502, and the click mechanism 510 is provided at the portion. The click mechanism 510 is a spring 510a fixed to the second member 502, a V-shaped recess 510b provided on the first member 501, and a sphere that is partially fitted into the recess 510b. Sphere 510c to be connected.

  When the first member 501 is in a predetermined position with respect to the second member 502, the ball 510c is fitted into the recess 510b and pressed against the first member 501 by the spring 510a. Therefore, as shown in FIG. 6, even when a rotational force about the rotational axis 503 is applied by driving the leg joint of the walking robot 1, if the rotational force is smaller than the force pushing the ball 510c out of the recess 510b, The relative rotation between the first member 501 and the second member 502 is prevented. That is, the ball 510 c functions as an obstacle that prevents relative rotation between the first member 501 and the second member 502. On the other hand, when the rotational force becomes larger than the force pushing the ball 510c out of the recess 510b, the ball 510c is pushed out of the recess 510b, so that the relative rotation between the first member 501 and the second member 502 is not prevented. Done smoothly. Accordingly, the click mechanism 510 corresponds to an urging unit according to the present invention that urges the first member 501 in a direction that prevents relative rotation between the first member 501 and the second member 502. Further, the click mechanism 510 prevents the first member 501 from easily rotating and moving with respect to the second member 502, and the posture of the walking robot from being unstable.

  7 is a motor for driving the ankle roll joint 20L / R shown in FIG. 1, and 521 shown in FIG. 7 is a portion that houses a reduction gear that decelerates and increases the output of the motor 520. 522 shown in FIG. 7 is a cover for accommodating the pitch joint 18L / R of the ankle joint.

  In the walking robot 1 having the leg tip portion 540 and the joint 500 configured as described above, the joint of the leg of the walking robot 1 excluding the joint 500 is driven as shown in FIG. A rotational force can be applied. And when this rotational force is given, after the ball | bowl 510c in the click mechanism 510 is extruded from the hollow 501c, relative rotation is performed between the 1st member 501 and the 2nd member 502, and a walking robot The direction of 1 is changed. At this time, regardless of the frictional force between the first member 501 and the walking road surface, in other words, against the substantially constant frictional force between the first member 501 and the second member 502 regardless of the road surface condition of the walking road surface. Thus, the direction changing operation of the walking robot 1 is performed. More precisely, the elastic force of the winding spring 506 in addition to the frictional force becomes a resistance during the direction changing operation of the walking robot 1. Therefore, regardless of the road surface condition of the walking road surface, the energy consumption during the direction changing operation becomes substantially constant, and the increase can be suppressed.

In addition, when the leg tip portion 540 is separated from the walking road surface after the direction changing operation of the walking robot 1 is finished, the first member 501 is returned to the position before the relative rotation is caused by the winding spring 503 in the direction in which the first rotation is performed. A rotational force is applied to one member 501. Further, the first member 501 is moved into the second member 50 by the action of the ball 510b trying to fit into the recess 510c in the click mechanism 510.
2 always returns to a predetermined position.

  In this embodiment, the click mechanism 510 uses the elastic force of the spring 510a as an urging force, but a piston driven by air pressure may be used instead of the elastic force of the spring 510a. By controlling the air pressure supplied to the piston, it is possible to control the urging force that urges the first member 501 in a direction that prevents relative rotation between the first member 501 and the second member 502. .

It is a figure which shows the schematic skeleton figure of the lower half body of the walking robot which is a walking robot which concerns on embodiment of this invention, and has two legs. In the walking robot which concerns on embodiment of this invention, it is a figure which shows the detailed structure of the joint in connection with direction change operation | movement provided in a leg tip part. In the walking robot which concerns on embodiment of this invention, it is a figure which shows the air pressure control circuit which performs the air pressure control in the joint in connection with direction change operation | movement. In the walking robot which concerns on embodiment of this invention, it is a figure which shows schematic structure of the control apparatus comprised from the motor etc. which are an actuator of the joint of a solenoid valve or a walking robot. In the walking robot which concerns on embodiment of this invention, it is a figure which shows schematically the contact relationship of the 1st member at the time of direction change operation | movement, a 3rd member, a 1st resin board, and a 2nd resin board. In the walking robot which concerns on embodiment of this invention, it is a figure which shows the basic principle of direction change operation | movement. In the walking robot which concerns on embodiment of this invention, it is a 2nd figure which shows the detailed structure of the joint in connection with direction change operation | movement provided in a leg tip part.

Explanation of symbols

1 ... Walking robot 10 ... Joint 12 ... Joint 14 ... Joint 16 ... Joint 18 ... Joint 20 ... Joint 24 ... Leg tip 30 ... Thigh link 32 ... Sne link 52 ... Piston, second member 54 ... Cylinder 56 ... Pressure chamber 62 ... Rotary shaft 64 ... Three members 66 ... First member 70 ... First resin plate 72 ... Second resin plate 80 ... Return spring 90 ... Accumulation tank 94 ... Solenoid valve 100 .... CPU
500 ... Joint 501 ... First member 502 ... Second member 503 ... Rotating shaft 504 ... Resin plate 506 ... Winding spring 510 ... Click mechanism 510a ... Spring 510b ... Recess 510c ... Ball

Claims (8)

In a walking robot having at least two legs composed of a plurality of link members and joint portions connecting the link members, and walking by driving the legs,
A leg tip is provided at the tip of the leg,
The leg tip portion includes a first member that contacts the walking road surface and a second member that does not contact the walking road surface, and the first member is higher than the second member in the height direction of the walking robot. The walking robot is provided on a side, and the first member is rotatable relative to the second member with the height direction of the walking robot as a rotation axis. Between the first member and the second member, there is provided a friction control member having a predetermined frictional force between the first member and the second member, and the first member and the second member The walking robot according to claim 1, wherein the relative rotation is performed through the friction control member. A walking robot direction changing means for rotating and changing the direction of the walking robot by executing relative rotation between the first member and the second member while the first member is in contact with the walking road surface. The walking robot according to claim 1, further comprising a walking robot. The walking robot orientation changing means is determined by a load center in each first member in a state where each first member is in contact with the walking road surface in at least two legs having the leg tip portion. By applying a driving force to the legs in the same rotational direction along the virtual circle, the first member and the second member are rotated relative to each other, and the direction of the walking robot is changed. The walking robot according to claim 3. Biasing means for biasing the first member in a direction to prevent relative rotation between the first member and the second member;
When relative rotation between the first member and the second member is performed, the urging force applied to the first member by the urging means is reduced, or the urging means is applied to the first member. The walking robot according to any one of claims 1 to 4, wherein the bias is released. The walking according to any one of claims 1 to 4, further comprising braking means for controlling prohibition of relative rotation between the first member and the second member or releasing the prohibition. robot. The walking robot according to claim 6, wherein relative rotation between the first member and the second member is prohibited by the braking unit when the walking robot is walking. In the leg tip portion, a third member different from the first member also contacts the walking road surface, and the third member rotates relative to the second member around the rotation axis. If you do not
The braking means transmits the relative rotational force between the first member and the second member, and cancels the ground contact state of the third member with the walking road surface. And relative rotation between the second member and the second member
By blocking transmission of relative rotational force between the first member and the second member, and grounding the first member and the third member to the walking road surface, the first member and the second member The walking robot according to claim 6 or 7, wherein relative rotation with the second member is prohibited.

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