JP7621824B2 - robot - Google Patents

Description

This disclosure relates to robots.

The ride-on robot disclosed in Patent Document 1 is equipped with a seat on which a rider sits and a pair of leg links. When the seat is lowered to allow a rider to board the robot in Patent Document 1, the pair of leg links are bent to move the knee joints backward so as not to impede boarding.

Patent No. 4055667

The robot in Patent Document 1 is configured so that the length from the ankle joint to the toes in front of the ankle joint is relatively long, and the center of gravity of the robot is located forward of the ankle joint. Also, as described above, when a passenger boards the robot in Patent Document 1, the knee joint moves backward and away from the center of gravity. Therefore, in the robot in Patent Document 1, the load on the pair of leg links, and therefore the torque for bending the pair of leg links, becomes relatively large. Also, depending on the direction in which the pair of leg links bend, the pair of leg links may hinder the passenger from boarding. Also, if the seat is not lowered sufficiently, it becomes difficult for the passenger to board the robot.

The objective of this disclosure is to provide a robot that can reduce the load on the legs when an object is loaded and can easily load the object.

In order to achieve the above object, the robot of the present disclosure comprises a main body and a pair of legs connected to the main body, and operates in a mode selected from a group of modes including a mounting mode which is a mode for stabilizing the posture of the main body, wherein each of the pair of legs has an upper leg member, a lower leg member, a first joint which connects the main body and the upper leg member, and a second joint which connects the upper leg member and the lower leg member, and when the mounting mode is selected, the first joint rotates the upper leg member relative to the main body so that the second joint is positioned forward of the first joint and outboard of the first joint in the width direction of the main body, and the second joint rotates the lower leg member relative to the upper leg member so that the position of the main body is lowered, the distance between the second joints in the width direction of the main body is greater than the length of the main body in the width direction, and in a mounting posture in which an object is mounted in the mounting mode , the second joint is positioned above the first joint.

The robot disclosed herein can reduce the load on the legs when an object is loaded, and can easily load the object.

FIG. 1 is a schematic diagram of a robot according to an embodiment of the present disclosure, illustrating a basic movement posture of the robot in a movement mode. FIG. 2 is a top side view of the robot shown in FIG. 1 . FIG. 2 is a bottom side view of the robot shown in FIG. 1 . FIG. 1 is a schematic diagram of a robot according to an embodiment of the present disclosure, illustrating the mounting posture of the robot in a mounting mode. FIG. 5 is a top side view of the robot shown in FIG. 4 . FIG. 5 is a bottom side view of the robot shown in FIG. 4 . FIG. 13 is a diagram showing a trajectory of a third joint in a transition mode in which the mode is transitioned from the mounted mode to the mobile mode. FIG. 13 is a diagram showing a trajectory of a third joint in a transition mode in which the mode is transitioned from the mounted mode to the mobile mode.

Below, the robot 1 according to an embodiment of the present disclosure will be described with reference to the drawings. In the following, the direction approaching the surface on which the robot 1 is placed is referred to as downward, the direction away from the surface is referred to as upward, the direction toward which the robot 1 moves forward is referred to as forward, the opposite direction is referred to as backward, and the directions toward the left and right from the robot 1 facing forward are referred to as left and right. In FIG. 1, the upper and lower sides are respectively above and below the robot 1, the left and right sides are the front and rear of the robot 1, and the front and rear sides of the paper correspond to the left and right sides of the robot 1.

The robot 1 is a mounted robot that moves with objects such as people and goods on board. Figure 1 shows the robot 1 resting on a support surface S. The support surface S is the ground or a floor surface. The robot 1 shown in Figures 1 to 3 is in a basic movement posture in a movement mode, which will be described later.

As shown in Figures 1 to 6, the robot 1 has a main body 10 and a pair of legs 20. The main body 10 has a mounting part 11 and a connection part 12.

The mounting unit 11 is provided so that an object can be mounted on it. The mounting unit 11 is provided so that a person M can sit on it while facing forward of the robot 1.

The connection part 12 is fixed to the bottom surface of the mounting part 11. A pair of legs 20 are connected to the connection part 12.

The pair of legs 20 are connected to both the left and right sides of the connection part 12. The pair of legs 20 operate to move the main body part 10. In other words, the robot 1 is configured to be able to move by walking on two legs. The pair of legs 20 are configured similarly to each other. Below, only one leg 20 will be described.

The leg 20 has one upper leg member 21, one lower leg member 22, and one foot member 23. The leg 20 also has first to third joints J1, J2, and J3.

The first joint J1 connects the connection part 12 and the first end of the upper leg member 21 so as to rotate relative to one another. In the basic movement posture, the first joint J1 tilts the upper leg member 21 from rear to front as it moves from top to bottom.

The first joint J1 operates to rotate the connection part 12 and the upper leg member 21 relative to each other around three axes that intersect at the first rotation center RC1. These three axes are the first ω-axis ω1, the φ-axis φ1, and the first ψ-axis ψ1. The first ω-axis ω1 is an axis obtained by projecting the axis A, which passes through the first rotation center RC1 and extends along the direction in which the upper leg member 21 extends, onto an imaginary horizontal plane on which the first rotation center RC1 is located. In the basic movement posture, the first ω-axis ω1 extends along the front-to-rear direction.

The φ-axis φ1 is an axis that extends in the up-down direction. The first ψ-axis ψ1 is an axis that is perpendicular to the first ω-axis ω1 and the φ-axis φ1. In other words, in the basic movement posture, the first ψ-axis ψ1 extends in the left-right direction. The first joint J1 corresponds to a human hip joint.

The second joint J2 connects the second end of the upper leg member 21 and the first end of the lower leg member 22 so that they can rotate relative to each other. In the basic movement posture, the second joint J2 tilts the lower leg member 22 so that it tilts from front to rear as it moves from top to bottom.

The second joint J2 operates to rotate the upper leg member 21 and the lower leg member 22 relative to each other around a single axis passing through the second rotation center RC2 located on the above-mentioned axis A. This single axis is the second ψ-axis ψ2 that is parallel to the first ψ-axis ψ1. The second joint J2 corresponds to a human knee joint.

The third joint J3 connects the second end of the lower leg member 22 and the foot member 23 so as to rotate relative to each other. In the basic movement posture, the third joint J3 positions the foot member 23 so that it extends forward from the second end of the lower leg member 22 in the front-to-rear direction.

The third joint J3 operates to rotate the lower leg member 22 and the foot member 23 relative to each other around two mutually orthogonal axes at the third rotation center RC3. These two axes are the second ω-axis ω2 and the third ψ-axis ψ3. The second ω-axis ω2 is an axis parallel to the first ω-axis ω1. That is, in the basic movement posture, the second ω-axis ω2 extends along the front-to-rear direction. Also, in the basic movement posture, the second ω-axis ω2 and the first ω-axis ω1 overlap in a plan view. The third ψ-axis ψ3 is an axis parallel to the first ψ-axis ψ1 and the second ψ-axis ψ2.

The upper leg member 21, the lower leg member 22, and the foot member 23 may be composed of multiple members separated from each other. Furthermore, when the upper leg member 21, the lower leg member 22, and the foot member 23 are composed of multiple members separated from each other, the leg 20 may further include a joint portion that connects the multiple separated parts so that they can rotate relative to each other. In other words, the leg 20 may have a structure different from that of a human leg, for example, a structure that includes multiple joints equivalent to knee joints.

Furthermore, two wheels 24 are attached to the foot member 23, which come into contact with the support surface S and rotate relative to the foot member 23. The two wheels 24 are arranged along the second ω-axis ω2. In other words, the two wheels 24 are arranged on the foot member 23 so as to be aligned along the front-to-rear direction in the basic movement posture. Furthermore, the first to third joints J1, J2, J3 operate to change the orientation and inclination of the foot member 23, thereby changing the orientation and inclination of the wheels 24.

It goes without saying that the number of wheels 24 is not limited to two. For example, if there is one wheel 24, the leg 20 can be made lighter and more compact. Also, if there are three or more wheels 24, two or more wheels 24 can be in contact with the support surface S even in a place where the area of the support surface S is small (e.g., stairs). In other words, the robot 1 can be stabilized. Note that a pair of legs 20 does not have to have wheels 24.

Furthermore, the pair of legs 20 have multiple drive devices (not shown) that respectively drive the first to third joints J1, J2, J3 and the wheels 24. The drive devices are, for example, servo motors.

The robot 1 also operates in a mode selected from a group of modes including a plurality of modes. The group of modes includes at least a moving mode, a mounting mode, and a transition mode.

The movement mode is a mode in which the robot 1 moves. When the movement mode is selected, the robot 1 takes the basic movement posture shown in Figures 1 to 3. The robot then moves by operating the first to third joints J1, J2, J3 so that the pair of legs 20 extends and bends. The robot 1 also moves by rotating the wheels 24. Furthermore, the robot 1 moves by a combination of the operation of the first to third joints J1, J2, J3 and the rotation of the wheels 24.

In addition, in the movement mode, the pair of legs 20 operate to keep the height of the main body 10 relative to the support surface S approximately constant. The height of the main body 10 in the movement mode is set so that the eye level of a person M sitting on the mounting unit 11 is approximately equal to the eye level of a person M standing independently. Therefore, a person M sitting on the mounting unit 11 can move without feeling uncomfortable compared to when walking independently.

The mounting mode is a mode used, for example, when mounting an object on the mounting unit 11 or when the mounting unit 11 is to be stably stationary. In the mounting mode, the mounting unit 11 and the main body 10 are in a position that allows a person M to board. In addition, in the mounting mode, the mounting unit 11 and the main body 10 are in a position that allows an object mounted on the mounting unit 11 to remain stationary so as not to fall. In other words, the mounting mode is a mode in which the robot 1 does not move and the position of the main body 10 is stabilized. When the mounting mode is selected, the robot 1 takes the mounting position shown in Figures 4 to 6. When the mounting mode is selected while in the moving mode, the robot 1 goes through the transition mode to enter the mounting mode. In the mounting mode, the pair of legs 20 do not move.

When the mounting mode is selected, that is, when transitioning to the mounting posture, the first joint J1 rotates the upper leg member 21 relative to the main body 10 so that the second joint J2 is positioned forward of the first joint J1 and outboard of the first joint J1 in the width direction of the main body 10. Thus, in the mounting mode, the two first ω-axes ω1 of the pair of legs 20 are V-shaped in a plan view. Also, in the mounting posture, the second joint J2 is positioned above the first joint J1.

When the mounting mode is selected, the second joint J2 rotates the lower leg member 22 relative to the upper leg member 21 so that the mounting unit 11 and therefore the main body unit 10 are lowered. Specifically, the second joint J2 operates to position the third joint J3 rearward of the second joint J2. In addition, in the mounting posture, the third joint J3 is located forward of the first joint J1. In other words, in the mounting posture, the third joint J3 is located between the first joint J1 and the second joint J2 in the front-to-rear direction.

Furthermore, in the mounting position, the distance between the second joints J2 in the width direction of the main body 10 is greater than the length of the main body 10 in the width direction. Therefore, the main body 10 can be positioned further downward, making it easier to mount an object such as a person M on the mounting part 11.

In addition, in the mounting position, the distance between the lower leg members 22 in the width direction of the main body 10 is greater than the length of the main body 10 in the width direction. In addition, in the mounting position, the second ω-axis ω2 and the first ω-axis ω1 coincide in a plan view. This allows the main body 10 to be positioned further downward, making it easier to mount an object such as a person M on the main body 10 and stabilizing the posture of the robot 1. In addition, the pair of legs 20 can be prevented from getting in the way when mounting an object.

The transition mode is the mode through which the vehicle moves from the mounted mode to the mobile mode. The transition mode is the mode through which the vehicle moves from the mobile mode to the mounted mode.

When the mode is shifted from the mounted mode to the moving mode, the pair of legs 20 operate so that the posture of the robot 1 changes from the mounted posture to the basic moving posture. On the other hand, when the mode is shifted from the moving mode to the mounted mode, the pair of legs 20 operate so that the posture of the robot 1 changes from the basic moving posture to the mounted posture.

The main body 10 is also provided with a control device (not shown) that controls the robot 1. The control device controls a plurality of drive devices that respectively drive the first to third joints J1, J2, J3 and the wheels 24, thereby operating the pair of legs 20. The control device includes a movement operation unit and a switching operation unit (not shown).

The movement operation unit sets the movement direction and amount of movement of the robot 1 in the movement mode. The control device operates the pair of legs 20 based on the operation of the movement operation unit. The movement operation unit is, for example, a joystick. The movement operation unit may be disposed on the mounting unit 11. In that case, the operability of the robot 1 can be improved by disposing it in a position that is easy for the person M sitting on the mounting unit 11 to operate.

The switching operation unit selects a mode, for example, switching between a moving mode and a mounting mode. When the switching operation unit is operated while the robot 1 is operating in the moving mode, the pair of legs 20 operate so that the robot 1 assumes the basic moving posture. When the robot 1 assumes the basic moving posture, a transition to the mounting mode via the transition mode is initiated.

When the switching operation unit is operated while the robot 1 is operating in the mounted mode, it transitions to the moving mode via the transition mode. At this time, the posture of the robot 1 changes from the mounted posture to the basic moving posture. The switching operation unit is, for example, a switch. The switching operation unit may be disposed on the mounting unit 11. In this case, the operability of the robot 1 can be improved by disposing it in a position that is easy for the person M sitting on the mounting unit 11 and a person standing independently to operate.

The control device may be equipped with an input unit into which a destination is input, and may be configured to operate the pair of legs 20 so that the robot 1 arrives at the destination input to the input unit even if the movement operation unit is not operated.

The control device may not be located on the robot 1, but may be configured to remotely control the robot 1 via wired or wireless communication.

Next, the operation of the pair of legs 20 in the transition mode when transitioning from the mounted mode to the moving mode, that is, when the posture changes from the mounted posture to the basic moving posture, will be described with reference to FIG. 7. FIG. 7 shows the leg 20 as viewed from below. When the posture of the robot 1 changes from the mounted posture to the basic moving posture, the operation of the pair of legs 20 is symmetrical, so only the operation of the right leg 20 will be described. The operation of the leg 20 in the transition mode means that the first to third joints J1, J2, J3 operate and the wheel 24 rotates.

When the posture of the robot 1 changes from the mounted posture to the basic moving posture, the legs 20 operate to extend and the wheels 24 rotate to move the foot members 23 along the support surface S toward the inside in the width direction of the main body 10. The legs 20 also operate to prevent the wheels 24 from tilting with respect to the support surface S, that is, to maintain the rotation axis of the wheels 24 parallel to the support surface S. The wheels 24 rotate in contact with the support surface S, causing the foot members 23 to move along the support surface S.

When the posture of the robot 1 changes from the mounted posture to the basic moving posture, the leg 20 operates so that the third joint J3 traces the trajectory indicated by the three thick arrows in FIG. 7. The trajectory indicated by the thick arrows in FIG. 7 is specifically the trajectory of the third rotation center RC3. The trajectory indicated by the thick arrows in FIG. 7 is traced on a virtual horizontal plane (hereinafter referred to as the virtual horizontal plane) that passes through the third rotation center RC3. In other words, the trajectory indicated by the thick arrows in FIG. 7 is the trajectory in plan view that is inverted in the left-right direction.

When the leg 20 operates so that the third rotation center RC3 traces the trajectory shown by the thick arrow in FIG. 7, the first rotation center RC1 and therefore the main body 10 rise along a direction perpendicular to the support surface S. In other words, when the support surface S is a horizontal plane, the mounting unit 11 moves vertically upwards, not diagonally upwards. Therefore, in the transition mode, it is possible to prevent an object such as a person M mounted on the mounting unit 11 from slipping off, and to prevent vibrations caused by the robot 1 attempting to assume a stable posture. In addition, because the mounting unit 11 moves upwards along the vertical direction, it is possible to prevent vibrations from occurring in a direction perpendicular to the vertical direction of the robot 1.

In FIG. 7, the leg 20 in the mounting position is shown by a solid line and has the suffix "(a)" added to its reference number. In FIG. 7, the leg 20 in the basic moving position is shown by a two-dot chain line and has the suffix "(b)" added to its reference number.

The following describes the trajectory of the third rotation center RC3 when the posture of the robot 1 changes from the mounting posture to the basic movement posture in the transition mode. The trajectory of the third rotation center RC3 is drawn so as to follow the first imaginary circle IC1, the second imaginary circle IC2, and the imaginary straight line IL.

The first imaginary circle IC1 is a circle of any radius in a virtual horizontal plane that passes through the third rotation center RC3 in the mounted attitude and is tangent to the second ω axis ω2 in the mounted attitude.

The second imaginary circle IC2 is a circle with an arbitrary radius that passes through the third rotation center RC3 in the basic movement posture and is tangent to the second ω-axis ω2 in the basic movement posture on the imaginary horizontal plane. The size of the second imaginary circle IC2 is determined so that there is one or less intersection with the first imaginary circle IC1. Specifically, there is zero intersection between the first imaginary circle IC1 and the second imaginary circle IC2. In other words, the first imaginary circle IC1 and the second imaginary circle IC2 are separated from each other.

The imaginary straight line IL is a straight line tangent to the first imaginary circle IC1 and the second imaginary circle IC2.

When the posture of the robot 1 changes from the mounted posture to the basic moving posture, the leg 20 operates to move the third rotation center RC3 from point P1 along the first imaginary circle IC1 to point P2. Point P1 is the point where the third rotation center RC3 is located in the mounted posture. Point P2 is the tangent point between the first imaginary circle IC1 and the imaginary straight line IL.

Continuing, as the legs 20 move, the third center of rotation RC3 moves from point P2 along the imaginary line IL to point P3, which is the tangent point between the second imaginary circle IC2 and the imaginary line IL. As the legs 20 move further, the third center of rotation RC3 moves from point P3 along the second imaginary circle IC2 to point P4, where the third center of rotation RC3 is located in the basic movement posture.

When the third rotation center RC3 is located at point P4, the robot 1 assumes the basic movement posture, and the transition to the movement mode is completed. As described above, the trajectory traced by the third rotation center RC3 has two arcs. Furthermore, when the transition mode is completed, the robot 1 assumes the basic movement posture, and so the wheels 24 of each of the pair of legs 20 face in the same direction, specifically, the direction in which the robot 1 moves forward. In other words, the wheels 24 of each of the pair of legs 20 face in the direction in which the robot 1 is moving.

The amount of movement of the third rotation center RC3 on the first imaginary circle IC1, the amount of movement on the imaginary straight line IL, and the amount of movement on the second imaginary circle IC2 can be set arbitrarily by adjusting the size of the first imaginary circle IC1 and the size of the second imaginary circle IC2. Furthermore, if the second imaginary circle IC2 and the first imaginary circle IC1 intersect at one point, the imaginary straight line IL is not included in the trajectory, and point P2 and point P3 are the same point.

The trajectory traced by the third rotation center RC3 is the trajectory traced when the posture of the robot 1 changes from the mounted posture to the basic moving posture in the transition mode. Conversely, when the posture of the robot 1 changes from the basic moving posture to the mounted posture in the transition mode, the leg 20 operates so that the third rotation center RC3 follows the trajectory described above in the reverse direction.

This disclosure is not limited to the embodiments described so far. As long as they do not deviate from the gist of this disclosure, various modifications to this embodiment and forms constructed by combining components of different embodiments are also included within the scope of this disclosure.

For example, when the posture of the robot 1 changes from the mounted posture to the basic moving posture as described above, the legs 20 operate so that the wheels 24 are not tilted relative to the support surface S. On the other hand, when the posture of the robot 1 changes from the mounted posture to the basic moving posture, the legs 20 may operate so that the wheels 24 are tilted relative to the support surface S at a certain point on the trajectory.

When the wheel 24 is tilted, the third joint J3 operates so that the foot member 23 rotates around the second ω-axis ω2. That is, when the wheel 24 is tilted, the foot member 23 tilts in the width direction of the foot member 23. When the wheel 24 is tilted to one side in the width direction of the foot member 23, the load applied to one side in the width direction of the foot member 23 becomes greater than the load applied to the other side in the width direction of the foot member 23.

Below, with reference to FIG. 8, a case where the leg 20 operates to tilt the wheel 24 relative to the support surface S when the posture of the robot 1 changes from the mounted posture to the basic movement posture in the transition mode will be described. FIG. 8 shows the leg 20 as viewed from below. In FIG. 8, the dashed arrow indicates the trajectory of the third rotation center RC3 when the inclination angle of the wheel 24 relative to the support surface S changes. In FIG. 8, the solid arrow indicates the trajectory of the third rotation center RC3 when the foot member 23 moves.

The third rotation center RC3 is located on the second ω-axis ω2 when the wheel 24 is not inclined relative to the support surface S, and moves along the width direction of the foot member 23 as the inclination angle of the wheel 24 relative to the support surface S changes. The second ω-axis ω2 and the width direction of the foot member 23 are perpendicular to each other.

When the posture of the robot 1 changes from the mounted posture to the basic moving posture, the third rotation center RC3 moves from point P5 to point P12 in a planar view, as shown in FIG. 8. Point P5 is the position of the third rotation center RC3 when the robot 1 is in the mounted posture. Point P12 is the position of the third rotation center RC3 when the robot 1 is in the basic moving posture.

In addition, the third rotation center RC3 moves along the third imaginary circle IC3 and the fourth imaginary circle IC4 as it moves from point P5 to point P12.

The third imaginary circle IC3 is a circle having an arbitrary radius that passes through point P6 and is tangent to a second imaginary straight line IL2 that is parallel to the second ω-axis ω2 in the mounting position. Point P6 is a point that is located on the outer side of point P5 in the width direction of the main body 10 in the width direction of the foot member 23 in the mounting position. The distance from point P5 to point P6 is distance D1. Distance D1 can be set arbitrarily.

The fourth imaginary circle IC4 is a circle tangent to both the third imaginary line IL3 and the fourth imaginary line IL4. The third imaginary line IL3 is a line that passes through point P11 and is parallel to the second ω-axis ω2 in the basic movement posture. Point P11 is a point located inside point P12 in the width direction of the main body 10 in the width direction of the foot member 23 in the basic movement posture. The distance from point P12 to point P11 is distance D2. Distance D2 can be set arbitrarily. The fourth imaginary line IL4 is a line that is parallel to the fifth imaginary line IL5 and has a distance from the fifth imaginary line IL5 that is the sum of distance D1 and distance D2. The fifth imaginary line IL5 is a line that is tangent to the third imaginary circle IC3 at point P7, which will be described later.

The radius of the third imaginary circle IC3 and the fourth imaginary circle IC4 are set so that they have two intersections.

When the robot 1 is in the mounted position and the wheels 24 are not tilted, the third center of rotation RC3 is located at point P5. When the third joint J3 operates and the wheels 24 tilt outward in the width direction of the foot member 23 relative to the main body 10, the third center of rotation RC3 moves from point P5 to point P6 along the width direction of the foot member 23.

When the third rotation center RC3 is located at point P6, the load acting on the outer side of the body 10 in the width direction of the foot member 23 is greater than the load acting on the inner side of the body 10 in the width direction of the foot member 23.

Then, as the leg 20 operates with the wheel 24 tilted, the third rotation center RC3 moves from point P6 to point P7 toward the inside of the width direction of the main body 10 along the third imaginary circle IC3. Furthermore, as the third joint J3 operates to return the wheel 24 to an untilted state, the third rotation center RC3 moves from point P7 to point P8. Point P8 is a point located on the inside of the width direction of the main body 10 along the width direction of the foot member 23 when the third rotation center RC3 is located at point P7, compared to point P7. Point P8 is a point located a distance D1 away from point P7.

Furthermore, as the legs 20 operate with the wheels 24 not tilted, the third center of rotation RC3 moves from point P8 to point P9 parallel to the fifth imaginary line IL5. Point P9 is a point located outside the width direction of the main body 10 along the width direction of the foot member 23 when the third center of rotation RC3 is located at point P8, from point P10, which is the tangent point between the fourth imaginary circle IC4 and the fourth imaginary line IL4. Point P9 is a point away from point P10 by a distance D2.

Next, when the third rotation center RC3 is located at point P9, the third joint J3 operates and the wheel 24 tilts inward in the width direction of the main body 10 in the width direction of the foot member 23, thereby moving the third rotation center RC3 from point P9 to point P10.

When the third rotation center RC3 is located at point P10, the load acting on the inner side of the body 10 in the width direction of the foot member 23 is greater than the load acting on the outer side of the body 10 in the width direction of the foot member 23.

Then, as the legs 20 operate with the wheels 24 tilted, the third rotation center RC3 moves from point P10 to point P11 along the fourth imaginary circle IC4 toward the inside of the width direction of the main body 10. Furthermore, as the third joint J3 operates to return the wheels 24 to an untilted state, the third rotation center RC3 moves from point P11 to point P12. When the third rotation center RC3 reaches point P12, the robot 1 assumes the basic movement posture and the transition to the movement mode is completed.

In addition, when comparing the trajectory when the wheel 24 is not tilted even once as shown in FIG. 7 with the trajectory when the wheel 24 is tilted as shown in FIG. 8, the radius of the virtual circle can be made larger when the wheel 24 is tilted. Therefore, compared to when the wheel 24 is never tilted, when the wheel 24 is tilted, the frictional resistance between the wheel 24 and the support surface S, and therefore the load on the drive unit, can be made smaller.

This disclosure is broadly applicable to robots.

Reference Signs List 1 Robot 10 Main body 20 Leg 21 Upper leg member 22 Lower leg member 23 Foot member 24 Wheel S Support surface

Claims (7)

A robot comprising a main body and a pair of legs connected to the main body, the robot operating in a mode selected from a group of modes including a mounting mode in which the attitude of the main body is stabilized,
each of the pair of legs includes an upper leg member, a lower leg member, a first joint portion connecting the main body portion and the upper leg member, and a second joint portion connecting the upper leg member and the lower leg member;
When the mounting mode is selected, the first joint portion rotates the upper leg member relative to the main body portion so that the second joint portion is positioned forward of the first joint portion and outward of the first joint portion in a width direction of the main body portion, and the second joint portion rotates the lower leg member relative to the upper leg member so that a position of the main body portion is lowered;
a distance between the second joints in a width direction of the main body is greater than a length of the main body in the width direction, and the second joints are located higher than the first joints in a mounting posture in which an object is mounted during the mounting mode .
robot. In the mounting mode, the distance between the lower leg members in the width direction of the main body is greater than the length of the main body in the width direction.
The robot according to claim 1. each of the pair of legs further includes a foot member, a third joint portion connecting the foot member and the lower leg member, and a wheel attached to the foot member;
In a transition mode in which the robot transitions from the mounting mode to a moving mode in which the robot moves, the pair of legs operate to extend and the wheels rotate, causing the foot members to move toward the inside in the width direction of the main body along a support surface.
The robot according to claim 2. In the transition mode, the pair of legs operate such that trajectories of the third joints of the pair of legs each have two arcs in a plan view, and such that the wheels face in a traveling direction of the robot when the transition to the movement mode is completed.
The robot according to claim 3. In the transition mode, the pair of legs operate such that the wheels are inclined with respect to the support surface when the third joint is on the two arcs of the trajectory.
The robot according to claim 4. A body part and a pair of legs having knee joints and connected to the body part via hip joints,
When an object is mounted on the main body, the pair of legs rotate relative to the main body so that the knee joints are positioned forward of the hip joint and outward of the hip joint in a width direction of the main body, and the knee joints of the pair of legs are bent so that the position of the main body is lowered.
In a mounting posture in which an object is mounted, the knee joint is located above the hip joint.
robot. A robot comprising a main body and a pair of legs connected to the main body, the robot operating in a mode selected from a group of modes including a mounting mode in which the attitude of the main body is stabilized,
each of the pair of legs includes an upper leg member, a lower leg member, a first joint portion connecting the main body portion and the upper leg member, and a second joint portion connecting the upper leg member and the lower leg member;
When the mounting mode is selected, the first joint portion rotates the upper leg member relative to the main body portion so that the second joint portion is positioned forward of the first joint portion and outward of the first joint portion in a width direction of the main body portion, and the second joint portion rotates the lower leg member relative to the upper leg member so that a position of the main body portion is lowered;
In the mounting mode, the distance between the lower leg members in the width direction of the main body is greater than the length of the main body in the width direction,
each of the pair of legs further includes a foot member, a third joint portion connecting the foot member and the lower leg member, and a wheel attached to the foot member;
In a transition mode in which the robot transitions from the mounted mode to a moving mode in which the robot moves, the pair of legs operate to extend and the wheels rotate, causing the foot members to move toward the inside in the width direction of the main body along a support surface.
robot.

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