Mobile

Abstract

To solve the problem that a conventional moving body capable of climbing over a step cannot move in multiple directions.SOLUTION: A moving body 1 includes: a chassis 2; two arms 10 arranged so that a horizontal first direction is a longitudinal direction and supported on the chassis 2 so as to be rotatable about an arm rotation shaft 70; two first wheels 51 respectively rotatable about steering shafts 64; two second wheels 52 supported on the respective arms 10 so as to be rotatable about the steering shaft 64; two third wheels 53 supported on the respective arms 10; arm rotating portions 71 that rotate the arms 10 with respect to the chassis 2; drive actuators 61 that respectively rotate the first wheel 51 and the second wheel 52 about axles; and steering actuators 63 that respectively rotate the first wheel 51 and the second wheel 52 about the steering shafts 64. The moving body 1 is movable in multiple directions and can climb over a step.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a mobile body having a plurality of wheels and capable of moving in multiple directions. [Background technology]

[0002] Conventionally, mobile bodies having multiple wheels and used for various purposes have been proposed. For example, such mobile body configurations may be used in autonomously moving robots. In order for such mobile bodies to travel on uneven ground, they require a mechanism for overcoming obstacles such as steps.

[0003] A typical example of a mechanism for climbing over steps is an endless track (see, for example, Patent Document 1 below).

[0004] There are also known moving body configurations that are configured to overcome steps by displacing the wheels up and down or by using arms that support the wheels to move the wheel drive mechanism up and down (see, for example, Patent Document 2 or Patent Document 3 below).

[0005] Patent Document 4 listed below describes the configuration of a mobile robot in which wheels are provided on legs that can rotate relative to the body.

[0006] Patent Document 5 listed below describes the configuration of a moving body in which a plurality of moving parts are provided below a base, with support shafts configured to be able to reciprocate. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2020-203680 [Patent Document 2] U.S. Patent No. 10,800,221 [Patent Document 3] Patent No. 6755044 [Patent Document 4] Japanese Patent Application Publication No. 2019-120101 [Patent Document 5] Japanese Patent Application Publication No. 2018-188013 Summary of the Invention [Problem to be solved by the invention]

[0008] However, there are cases where the above-mentioned mobile body is required to be able to perform precise positioning and to be maneuverable. To meet such needs, it is desirable that the mobile body be able to overcome steps and move in multiple directions.

[0009] Looking at this point in relation to conventionally known structures, for example, a moving body using an endless track, such as that described in Patent Document 1, can generally only move in a predetermined direction corresponding to the rotation direction of the endless track.

[0010] Furthermore, moving bodies using wheels, such as those described in Patent Documents 2, 3, and 4, are configured to be able to move in a predetermined direction relative to the body and to overcome steps.

[0011] For example, a moving body such as that described in Patent Document 5 can move in all directions and overcome obstacles in all directions. However, this moving body has six or more movable parts that can move back and forth, and the overall structure is complex.

[0012] An object of the present invention is to provide a mobile body that is movable in multiple directions and can overcome steps. [Means for solving the problem]

[0013] The mobile body of the first invention is a mobile body comprising: a chassis; two arms arranged on either side of the chassis so as to be aligned along a horizontal second direction perpendicular to a horizontal first direction, with a horizontal first direction being the longitudinal direction, and supported on the chassis so as to be rotatable around an arm rotation axis; two first wheels arranged on either side of the chassis so as to be aligned along the second direction, each rotatable around a steering axis; two second wheels supported on each arm at a position on the arm farther from the first wheel in the first direction than the arm rotation axis, each rotatable around the steering axis; two third wheels supported on each arm at a position closer to the first wheel in the first direction than the arm rotation axis; arm rotation units provided corresponding to each arm and rotating the corresponding arm relative to the chassis; drive actuators provided corresponding to each of the first and second wheels and rotating the corresponding wheel around an axle; and steering actuators provided corresponding to each of the first and second wheels and rotating the corresponding wheel around the steering axis.

[0014] This configuration allows the robot to move in multiple directions and overcome steps.

[0015] Furthermore, the mobile body of the second invention is a mobile body in which, compared to the first invention, the arm rotation axis of the arm is approximately parallel to the second direction, and the third wheel is held on the arm so that the axle is approximately parallel to the second direction.

[0016] With this configuration, it is possible to move stably in the first direction and overcome steps.

[0017] Furthermore, a moving body according to a third aspect of the present invention is a moving body according to the first or second aspect of the present invention, further comprising drive actuators provided in correspondence with the third wheels, respectively.

[0018] With this configuration, a larger driving force can be obtained even when going over a step or the like.

[0019] Furthermore, the movable body of the fourth invention is a movable body according to any one of the first to third inventions, further comprising two sub-arms arranged on either side of the chassis so as to be aligned along the second direction with the first direction being the longitudinal direction, and supported on the chassis so as to be rotatable relative to the chassis, and a first wheel is supported on the sub-arms.

[0020] This configuration allows for a variety of methods to overcome steps.

[0021] Furthermore, the mobile body of the fifth invention is a mobile body that, compared to any of the first to fourth inventions, further comprises a sub-link supported on the chassis so as to be rotatable around a rotation axis parallel to the arm rotation axis of the arm, and a support part that is connected to a part of the arm and a part of the sub-link and supports a second wheel, and the arm, the sub-link corresponding to the arm, and the support part are connected to form a parallel link.

[0022] With this configuration, the steering shaft of the second wheel can be maintained in a predetermined position regardless of the rotation angle of the arm. [Effects of the Invention]

[0023] According to the present invention, the moving body can be made movable in multiple directions and able to overcome steps. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a perspective view showing a configuration of a moving body according to an example of the present embodiment; [Figure 2] FIG. 10 is a perspective view showing an example of a state when the moving body moves in the left-right direction; [Figure 3] FIG. 10 is a side view showing an example of a state in which the moving body moves in the left-right direction. [Figure 4] FIG. 10 is a plan view illustrating the movement of the moving body. [Figure 5] FIG. 10 is a diagram showing an example of the moving object's operation of climbing over a step. [Figure 6]FIG. 10 is a perspective view showing the configuration of a moving body according to a first modified example of the present embodiment; [Figure 7] FIG. 10 is a perspective view showing the configuration of a moving body according to a second modification of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, embodiments of a moving body and the like will be described with reference to the drawings. Note that components with the same reference numerals in the embodiments perform similar operations, and therefore repeated description may be omitted.

[0026] In the following description, for the convenience of explaining the structure of the moving body, directions may be indicated based on a state in which the moving body is in contact with a horizontal road surface. Coordinates shown in the drawings are common to all drawings. The Z direction of the coordinates is a direction perpendicular to the horizontal plane. The X direction is a direction perpendicular to the Z direction, i.e., a horizontal direction. The Y direction is a direction perpendicular to the Z direction and perpendicular to the X direction. In other words, the Y direction is a horizontal direction perpendicular to the X direction. The Z direction is sometimes referred to as the up-down direction, the X direction as the front-to-back direction (the direction in which the second wheel is located in the moving body described below is the front; an example of the first direction), and the Y direction as the left-to-right direction (an example of the second direction). These directions are indicated solely for the convenience of explanation and do not limit the orientation, posture, etc. of the moving body of the present invention when in use, or the orientation, posture, etc. of each component.

[0027] (Embodiment)

[0028] In this embodiment, the moving body has a second wheel, a first wheel, and a third wheel, and is configured such that the second wheel and the third wheel are supported by a rotatable arm relative to a chassis arranged so that the longitudinal direction is the front-to-rear direction. The second wheel and the first wheel are driving wheels and configured to be steerable. The third wheel is not steerable but is a driving wheel. Note that the third wheel may be steerable or may be a driven wheel. The first wheel may also be supported by another rotatable arm. The arm may form a parallel link. Below, a moving body 1 configured in this manner will be described.

[0029] FIG. 1 is a perspective view showing the configuration of a moving object 1 according to an example of the present embodiment.

[0030] The moving body 1 includes a chassis 2, two arms 10, two first wheels 51, two second wheels 52, and two third wheels 53. Hereinafter, the first wheels 51, the second wheels 52, and the third wheels 53 may be collectively referred to as wheels 50 without distinction. The first wheels 51 may be referred to as rear wheels 51, and the second wheels 52 may be referred to as front wheels 52. In this case, "front" and "rear" are merely terms for distinguishing between the components and do not limit the direction of movement of the moving body 1. The moving body 1 also includes an arm rotation unit 71, a drive actuator 61, and a steering actuator 63 as parts that operate the respective parts.

[0031] In the moving body 1, the arm 10, the rear wheel 51, the front wheel 52, and the third wheel 53 are arranged approximately symmetrically with respect to the chassis 2. Here, symmetry means symmetry with respect to a plane that passes through the center of the chassis 2 and is perpendicular to the Y direction.

[0032] The mobile object 1 is usually placed on a substantially flat road surface R (shown in FIG. 3 ) and is capable of moving on the road surface R. The mobile object 1 includes, for example, a control unit (not shown) mounted on a chassis 2 (which may be configured, for example, by a computer or an electric circuit), a sensor unit that detects the surrounding conditions, and a battery used as a power source for each unit. The mobile object 1 is configured to be able to move autonomously in multiple directions on the road surface R based on control by the control unit, which is performed based on, for example, a predetermined program, detection results by the sensor unit, or instructions received from the outside. Note that the mobile object 1 is not limited to being able to move autonomously. For example, the mobile object 1 may be able to move on the road surface R by configuring various actuators to function based on preset programs, sequences, etc. Alternatively, the mobile object 1 may be able to move on the road surface R by receiving instructions from the outside to operate each actuator.

[0033] The chassis 2 may be said to be the main body of the moving body 1, or may be said to be the frame of the moving body 1. In this embodiment, the chassis 2 is configured to have, for example, a rectangular shape in a plan view. More specifically, the chassis 2 has an outer shape that is a rectangular parallelepiped as a whole. The chassis 2 may have a shape that is partially or entirely rounded. The chassis 2 may also have a polygonal shape in a plan view. In this embodiment, the chassis 2 has a shape that is roughly bilaterally symmetrical, but is not limited to this.

[0034] The arm 10 is, for example, a beam-like member that is linear in a plan view and has a curved portion in a side view. The two arms 10 are each arranged at the front side of the chassis 2 so that the longitudinal direction is the front-rear direction. The two arms 10 are arranged on both sides of the chassis 2 so as to be aligned along the left-right direction. That is, in the left-right direction, the right arm 10, the chassis 2, and the left arm 10 are arranged in this order. The two arms 10 have, for example, shapes that are symmetrical to each other and are arranged so as to be symmetrical to each other.

[0035] The shape of the arm 10 may be linear in side view, partially curved in plan view, or curved as a whole.

[0036] Each arm 10 is supported relative to the chassis 2 so as to be rotatable about an arm rotation axis 70 (in this embodiment, the rotation axis of an arm rotation unit 71 described below). In this embodiment, the arm rotation axis 70 passes through the longitudinal center of each arm 10. The arm rotation axis 70 is an axis disposed substantially horizontally. That is, the arm rotation axis 70 is substantially perpendicular to the longitudinal direction of each arm 10. In this embodiment, the arm rotation axis 70 is an axis substantially parallel to the left-right direction. The arm 10 is rotatable relative to the chassis 2 about the arm rotation axis 70 from a state in which the longitudinal direction is substantially horizontal. That is, the arm 10 is capable of swinging like a seesaw relative to the chassis 2 so that the front and rear sides of the arm 10 are displaced up and down about the arm rotation axis 70.

[0037] In this embodiment, the arms 10 are supported on the chassis 2 so as to be symmetrical on the left and right. That is, the arm rotation axes 70 of the two arms 10 overlap each other (are coaxial).

[0038] The arm rotation units 71 are provided to correspond to the two arms 10, respectively. Each arm rotation unit 71 is configured to rotate the corresponding arm 10 around the arm rotation shaft 70 relative to the chassis 2. For example, the control unit controls the operation of the arm rotation unit 71, causing the corresponding arm 10 to rotate around the arm rotation shaft 70. Furthermore, for example, the arm rotation unit 71 may be driven in response to an external instruction, causing the corresponding arm 10 to rotate.

[0039] The arm rotation unit 71 is an actuator capable of controlling the rotation angle. The arm rotation unit 71 is, for example, a servo motor or a stepping motor, but is not limited to these. For example, the arm rotation unit 71 may be an actuator such as a motor equipped with an encoder or the like and configured to be able to control the rotation angle. The arm rotation unit 71 may also be one that rotates the arm 10 using a hydraulic actuator. The arm rotation unit 71 may also be configured to include a support shaft as the arm rotation shaft 70 that rotatably supports the arm 10 with respect to the chassis 2, and a linear actuator that is arranged between a part of the arm 10 and the chassis 2 and changes the distance therebetween.

[0040] The rear wheels 51 are each disposed at the rear side of the chassis 2. The two rear wheels 51 are disposed on either side of the chassis 2 so as to be aligned in the left-right direction. That is, the right rear wheel 51, the chassis 2, and the left rear wheel 51 are arranged in this order in the left-right direction. The two rear wheels 51 are disposed in positions that are symmetrical left-right.

[0041] The rear wheels 51 are supported by support parts 15 fixed to the chassis 2. The support parts 15 that support the rear wheels 51 are, for example, but not limited to, metal fittings. The rear wheels 51 are provided so as to be rotatable relative to the support parts 15 around a substantially vertical steering axis 64. In other words, the rear wheels 51 are steerable wheels.

[0042] The front wheels 52 are each disposed on a front side of the chassis 2. When the two arms 10 are in a symmetrical position, the two front wheels 52 are disposed on both sides of the chassis 2 so as to be aligned in the left-right direction. That is, in the left-right direction, the right front wheel 52, the chassis 2, and the left front wheel 52 are arranged in this order. When the two arms 10 are in a symmetrical position, the two front wheels 52 are arranged so as to be symmetrical.

[0043] The front wheels 52 are supported by the arm 10. In this embodiment, the front wheels 52 are supported on the arm 10 via support parts 15 provided on the arm 10. The support parts 15 that support the front wheels 52 are, for example, metal fittings or the like fixed to the arm 10, but are not limited to this. The front wheels 52 are provided so as to be rotatable relative to the support parts 15 around a steering shaft 64. In other words, the front wheels 52 are steerable steering wheels. The steering shaft 64 of the front wheels 52 is configured to be in a substantially vertical position when the arm 10 is in a normal position. Here, the arm 10 being in a normal position refers to, for example, a position in which the front wheels 52 and the third wheel 53 both touch the ground when the mobile object 1 is on a horizontal road surface R.

[0044] In this embodiment, the front wheel 52 is supported at the front end of the arm 10. That is, the front wheel 52 is supported at a location on the arm 10 that is farther from the rear wheel 51 than the arm rotation shaft 70 is in the front-to-rear direction.

[0045] The third wheels 53 are each arranged laterally in the center of the chassis 2. When the two arms 10 are in a symmetrical position, the two third wheels 53 are arranged on both sides of the chassis 2 so as to be aligned in the left-right direction. That is, in the left-right direction, the third wheel 53 on the right side, the chassis 2, and the third wheel 53 on the left side are arranged so as to be aligned in this order. When the two arms 10 are in a symmetrical position, the two third wheels 53 are arranged so as to be symmetrical.

[0046] The third wheel 53 is supported by the arm 10. In this embodiment, the third wheel 53 is held by the arm 10 so that the axle is approximately parallel to the left-right direction. That is, in this embodiment, the third wheel 53 is a non-steered wheel, and the center plane of the third wheel 53 is approximately perpendicular to the left-right direction.

[0047] In the present embodiment, the third wheel 53 is supported at the rear end of the arm 10. That is, the third wheel 53 is supported at a position on the arm 10 that is closer to the rear wheel 51 than the arm rotation shaft 70 in the front-rear direction.

[0048] In this embodiment, the wheels 50 have approximately the same diameter. The front wheels 52, rear wheels 51, and third wheel 53 may have different diameters, or one of these wheels may have a different diameter from the other wheels. Each wheel 50 is disposed in a position where it can make contact with the road surface R under normal conditions. In other words, the vertical positions of the six wheels 50 are approximately the same under normal conditions.

[0049] In this embodiment, each of the six wheels 50 is a drive wheel that can rotate around an axle. That is, a drive actuator 61 is provided corresponding to each of the rear wheels 51, the front wheels 52, and the third wheel 53.

[0050] The drive actuator 61 rotates the corresponding wheel 50 around the axle. The drive actuator 61 is, for example, any of various motors. The drive actuator 61 may have a detection means such as an encoder that can detect the number of rotations of the wheel 50, i.e., the number of rotations of the axle, or may be a motor that can control the rotation angle, such as a stepping motor. The drive actuator 61 may also be configured to include a motor that serves as a drive source and a transmission mechanism (for example, one that uses gears, etc.) that transmits the torque of the motor to the axle. The drive actuator 61 may also have a clutch so that the wheel 50 can rotate freely.

[0051] As described above, in this embodiment, each of the six wheels 50 is a driving wheel, and thus the moving body 1 has a high driving force. That is, the moving body 1 can exert a high driving force by simultaneously driving a maximum of six wheels 50 that are in contact with the ground. In this case, it is desirable to set the steering angle of each wheel 50 so that the axles of the rear wheels 51 and the front wheels 52 are parallel to the left-right direction, similar to the axle of the third wheel 53.

[0052] It should be noted that each wheel 50 does not have to be configured to rotate independently by the drive actuator 61. For example, the front wheel 52 and the third wheel 53, which are supported by the same arm 10 by a power transmission mechanism such as gears, may be configured to operate together by a single drive actuator 61.

[0053] In this embodiment, the rear wheels 51 and the front wheels 52, which are steerable wheels, are configured to be steered around a steering shaft 64 by a steering actuator 63.

[0054] The steering actuator 63 steers the corresponding wheel 50 by rotating it about the steering shaft 64. The steering actuator 63 is an actuator capable of controlling the rotation angle. The steering actuator 63 is, for example, a servo motor or a stepping motor, and is held by the support part 15 together with the corresponding wheel 50. Note that the steering actuator 63 is not limited to this, and may be an actuator such as a motor that is equipped with an encoder or the like and is capable of controlling the rotation angle. Furthermore, the steering actuator 63 may have a clutch so that the wheel 50 can freely rotate about the steering shaft 64.

[0055] In this embodiment, the rear wheels 51 and the front wheels 52 can be rotated by a drive actuator 61 and can be steered by a steering actuator 63. The driving state of each wheel 50 around the axle and the steering shaft 64 is changed by the drive actuator 61 and the steering actuator 63, and accordingly the moving body 1 can move in multiple directions.

[0056] Since the third wheel 53 is not a steering wheel, it is preferable that the third wheel 53 is not on the ground (floating state) when the moving body 1 moves in a direction different from the forward / backward direction. In this embodiment, the third wheel 53 can be brought into a floating state by rotating the arm 10 so that the front wheel 52 is displaced downward relative to the chassis 2 from a state in which the third wheel 53 is on the ground.

[0057] Fig. 2 is a perspective view showing an example of the state of the movable body 1 when moving in the left-right direction, and Fig. 3 is a side view showing an example of the state of the movable body 1 when moving in the left-right direction.

[0058] For example, when the moving body 1 moves in the left-right direction, as shown in FIG. 2, the arm 10 rotates and the rear wheels 51 and front wheels 52 are steered. That is, the arm 10 rotates so as to tilt slightly forward. The rear wheels 51 and front wheels 52 are each steered so that their axles are approximately parallel to the front-to-rear direction. By rotating and steering the arm 10 in this manner, the rear wheels 51 and front wheels 52, which are drive wheels, can be driven in an attitude in which their center planes are parallel to the left-to-right direction. Furthermore, the third wheel 53, which faces in a direction different from the direction of movement, is lifted off the road surface R, preventing the third wheel 53 from contacting the road surface R and interfering with the movement of the moving body 1. Therefore, the moving body 1 can be moved in the left-to-right direction efficiently.

[0059] In addition to this, by steering the rear wheels 51 and the front wheels 52, which are steerable wheels, with the third wheels 53 in a lifted state, the moving body 1 can move in various ways.

[0060] FIG. 4 is a plan view illustrating the movement of the moving body 1. As shown in FIG.

[0061] Fig. 4 shows examples of movement modes, namely, turning on the spot (S11), steering (S12), and translation (S13). By setting the steering angles of the rear wheels 51 and front wheels 52 of the moving body 1 as follows, and by simplifying the rotation directions as shown by arrows in Fig. 4, the moving body 1 can be moved in each of the movement modes.

[0062] That is, in the case of turning on the spot, for example, it is as follows. In this case, the steering angle of each wheel 50 is set to an angle such that its central plane is tangent to an arc T that passes through each wheel 50 in a plan view. Then, each wheel 50 is driven in a predetermined rotational direction when viewed from the radial direction of the moving body 1. Note that turning on the spot here refers to a movement mode in which the moving body 1 turns so as to change its direction while keeping its position on the road surface R unchanged.

[0063] Further, when steering movement is performed, for example, as follows. In this case, the steering angle is set so that the center planes of the front wheels 52 are approximately parallel to each other, the center planes of the rear wheels 51 are approximately parallel to each other, and the center planes of the front wheels 52 and the rear wheels 51 are not parallel to each other. Then, each wheel 50 is driven in a direction such that the front wheels 52 and the rear wheels 51 are propelled in the same direction on the road surface R. For example, the front wheels 52 are steered and driven so as to propel the vehicle 1 leftward, and the rear wheels 51 are steered and driven so as to propel the vehicle 1 rightward. This realizes a movement mode in which the vehicle 1 moves forward and leftward while the chassis 2 rotates counterclockwise in a plan view.

[0064] Furthermore, when parallel movement is performed, for example, it is as follows. In this case, the steering angle is set so that all center planes of the front wheels 52 and the rear wheels 51 are approximately parallel to each other. Then, each wheel 50 is driven in a direction so as to propel the vehicle in the same direction on the road surface R. For example, each wheel 50 is steered and driven so as to propel the vehicle in a rightward direction. In this way, the vehicle 1 performs parallel movement in which the vehicle moves forward to the right as a whole while keeping the orientation of the chassis 2 unchanged.

[0065] The steering angles and rotational speeds of the rear wheels 51 and the front wheels 52 may be set appropriately according to the desired mode of movement.

[0066] In the moving body 1 according to this embodiment, the arm 10, to which the front wheels 52 are attached at the tip, can rotate relative to the chassis 2, so that the moving body 1 can overcome steps in front or behind. In addition, by rotating the arm 10 relative to the chassis 2 while the rear wheels 51 are in contact with the road surface R, the posture of the chassis 2 can be adjusted. Therefore, it is possible to easily meet the need for transportation with a stable posture, for example.

[0067] When climbing over a step in the movement direction, for example, the arm 10 may be rotated relative to the chassis 2 as follows.

[0068] FIG. 5 is a diagram showing an example of the moving object 1 climbing over a step.

[0069] FIG. 5 shows a scene from the side in which a moving object 1 on a road surface R climbs over a step B on the road surface R.

[0070] In this embodiment, the movable body 1 can displace the front wheels 52 and the third wheels 53 up and down relative to the chassis 2 by rotating the arms 10 relative to the chassis 2 using the arm rotation unit 71. That is, the movable body 1 is configured to be able to change the attitude of the chassis 2 with respect to the road surface R by rotating at least one arm 10. For example, when the arm 10 is rotated so that the front wheels 52 are displaced upward relative to the chassis 2, at least one of the front wheels 52 or the rear wheels 51 will be lifted up (floated) above the road surface R, depending on the location of the center of gravity of the movable body 1. When both arms 10 are rotated so that each front wheel 52 is lifted up relative to the chassis 2, it is possible to lift either the two front wheels 52 or the two rear wheels 51. In this embodiment, the movable body 1 is configured to move in a direction such that the lifted wheels 50 are closest to the step between the road surface R and the step B. That is, first, the lifted wheels 50 are placed on the step B, thereby enabling the movable body 1 to overcome the step. By setting the orientation of the moving body 1 relative to the position of the step to a predetermined orientation depending on the position of the step, the moving body 1 can be moved in either the forward or backward direction toward the step, thereby making it possible to overcome the step.

[0071] Assume that the moving body 1 moves toward a step B. In this case, the step B has an upper surface that is higher than the road surface R on which the moving body 1 is placed. The step between the road surface R and the step B is substantially parallel to the left-right direction and has a sufficient width.

[0072] First, it is assumed that the center of gravity of the moving body 1 is located, for example, closer to the rear wheel 51. In this case, the moving body 1 operates so as to follow, for example, steps S1 to S7 shown in FIG.

[0073] First, the moving body 1 moves forward to just before the step B (S1). Then, the arm 10 rotates relative to the chassis 2. In this case, the arm 10 is displaced in a direction such that the third wheel 53 moves downward away from the chassis 2. In other words, from a state in which all of the wheels 50 are substantially in contact with the road surface R, the two arms 10 rotate such that the front wheels 52 move upward. As a result, each wheel 52 moves upward away from the road surface R, and the third wheel 53 and the rear wheel 51 mainly come into contact with the road surface R.

[0074] Next, the moving body 1 is moved forward so that the lifted front wheels 52 are positioned above the step B (S2). Then, the arm 10 is rotated in the opposite direction to that described above, and the moving body 1 is moved further forward (S3). As the moving body 1 moves further forward, the rear wheels 51 are pulled up onto the step B, and all the wheels 50 come into contact with the upper surface of the step B (S4).

[0075] When the vehicle approaches a step that descends from the front end of step B to road surface R, arm 10 rotates relative to chassis 2 with front wheel 52 protruding from step B above road surface R. The direction of rotation in this case is a direction in which front wheel 52 is displaced downward relative to chassis 2. As a result, front wheel 52 comes into contact with road surface R (S5).

[0076] Thereafter, when the movable body 1 is moved forward and the third wheel 53 leaves the step B, the arm 10 rotates relative to the chassis 2 with the front wheel 52 in contact with the road surface R and the rear wheel 51 in contact with the step B. As a result, the third wheel 53 comes into contact with the road surface R (S6). As the movable body 1 is further moved forward and the rear wheel 51 passes over the step, the arm 10 returns to its normal state, allowing the movable body 1 to move over the step B and all of the wheels 50 to come into contact with the ground (S7).

[0077] Next, let us consider a case where the center of gravity of the moving object 1 is in the front. The orientation of the moving object 1 relative to the step is the opposite direction to the orientation described above. In other words, the step can be overcome by moving the moving object 1 backward with the orientation of the moving object 1 such that the step is located behind it.

[0078] In this case, for example, the moving object 1 may be made to operate in such a way that it follows the steps from step S1 to step S7 shown in FIG. 5 in the reverse order.

[0079] That is, first, the moving body 1 moves backward and is positioned in front of the step B (S7). Then, the arm 10 rotates relative to the chassis 2. In this case, the arm 10 is displaced in a direction in which the third wheel 53 moves downward away from the chassis 2. As a result, the chassis 2 tilts with respect to the road surface R, and the rear wheel 51 moves upward away from the road surface R. The front wheel 52 and the third wheel 53 supported by the arm 10 come into contact mainly with the road surface R.

[0080] Next, the moving body 1 moves backward so that the lifted rear wheel 51 comes onto the step B (S6). Then, the arms 10 rotate in the opposite direction to that described above so that the third wheel 53 comes into a lifted state, and the moving body 1 moves further backward. As a result, the third wheel 53 comes onto the step B (S5). As the moving body 1 moves further backward, the arms 10 return to their normal state as the rear wheel 51 passes over the step, and all the wheels 50 come into contact with the upper surface of the step B (S4).

[0081] Thereafter, when the vehicle approaches a downward step, the arm 10 rotates in a direction in which the front wheel 52 is displaced downward relative to the chassis 2, with the rear wheel 51 protruding from the step B above the road surface R. The vehicle 1 also moves backward as appropriate. As a result, the rear wheel 51 comes into contact with the road surface R (S3).

[0082] Thereafter, as the moving body 1 advances in the direction of movement and the third wheel 53 separates from the step B, the arm 10 rotates relative to the chassis 2 with the front wheel 52 in contact with the step B and the rear wheel 51 in contact with the road surface R. As a result, the third wheel 53 comes into contact with the road surface R (S2). As the moving body 1 further advances in the direction of movement and the arm 10 returns to being approximately horizontal, the moving body 1 moves over the step B and all the wheels 50 come into contact with the road surface R (S1).

[0083] As described above, in this embodiment, the moving body 1 can move in multiple directions by steering and driving the front wheels 52 and the rear wheels 51. In addition, it can move in a variety of movement modes. When moving in the forward / backward direction, the arm 10 can be used to ground the third wheel 53 in addition to the front wheels 52 and the rear wheels 51, thereby enabling more stable movement. Because the front wheels 52 and the rear wheels 51 can be steered separately, there is no need for differential turning, which has drawbacks such as requiring a large torque when under heavy load, and the moving body 1 can be moved efficiently in multiple directions.

[0084] Furthermore, the movable body 1 can overcome steps mainly in the forward and backward directions by rotating the arm 10. With a relatively simple configuration that limits the number of actuators used, the movable body 1 can be made to move in multiple directions and overcome steps.

[0085] The configuration of the moving body is not limited to that of the above-described embodiment, and modifications of this embodiment will be described below.

[0086] Modification 1 is as follows: That is, in addition to the arms that support the front wheels and the third wheel, an arm that supports the rear wheels may be provided rotatably with respect to the chassis.

[0087] FIG. 6 is a perspective view showing the configuration of a moving body 401 according to the first modification of this embodiment.

[0088] In the moving body 401 according to the first modification, the suspension mechanism by the arms 10 of the front wheel 52 and the third wheel 53 is the same as that of the moving body 1 according to the above-described embodiment. The moving body 401 is provided with two sub-arms 416 that support the rear wheel 51.

[0089] The sub arms 416 are, for example, beam-shaped members that are linear in plan view. The two sub arms 416 are each arranged at the rear side of the chassis 2 so that the longitudinal direction is the front-to-rear direction. The two sub arms 416 are arranged on both sides of the chassis 2 so as to be aligned along the left-to-right direction. That is, in the left-to-right direction, the right sub arm 416, the chassis 2, and the left sub arm 416 are arranged so as to be aligned in this order. The two sub arms 416 have, for example, shapes that are symmetrical to each other, and are arranged so as to be symmetrical to each other.

[0090] Each sub-arm 416 is supported by an arm rotation section 71 provided corresponding to it so as to be rotatable about an arm rotation shaft 70. The arm rotation shaft 70 of the sub-arm 416 is an axis that is approximately parallel to the left-right direction. The sub-arm 416 is rotatable about the arm rotation shaft 70 relative to the chassis 2 from a state in which the longitudinal direction of the sub-arm 416 is approximately horizontal, extending rearward from the arm rotation shaft 70. In this embodiment, the arm rotation shafts 70 of the two sub-arms 416 overlap each other.

[0091] In the first modification, the support portion 15 that supports the rear wheel 51 is fixed to the rear end portion of the sub arm 416. That is, the rear wheel 51 can be displaced up and down as the sub arm 416 rotates.

[0092] The moving body 401 also has a configuration basically similar to that of the above-described embodiment, and therefore can achieve the same effects as those described above. In this modified example, in addition to the front wheels 52, the rear wheels 51 can also be displaced up and down in accordance with the rotation of the sub arms 416. By adjusting the rotation angles of the two arms 10 and the two sub arms 416 relative to the chassis 2 according to the position of the step, it is possible to lift the wheels 50 closest to an ascending step off the road surface so that the step can be overcome, or to bring the wheels 50 closest to a descending step into contact with the road surface so that the step can be overcome smoothly.

[0093] Modification 2 is as follows: That is, the front wheels may be configured to be vertically displaceable by a parallel link mechanism.

[0094] FIG. 7 is a perspective view showing the configuration of a moving body 501 according to the second modification of this embodiment.

[0095] In Modification 2, a moving body 501 has basically the same configuration as the moving body 401 according to the above-described Modification 1. The moving body 501 uses a suspension method for the front wheels 52 and the rear wheels 51 that is different from that of the moving body 401.

[0096] That is, beam-shaped secondary links 510 are provided above the left and right arms 10. The secondary links 510 are supported by the chassis 2 so as to be rotatable about rotation axes parallel to the arm rotation axis 70. In this modified example, the support unit 15 supporting the front wheels 52 is connected to the front end of the arm 10 and the front end of the secondary link 510. The support unit 15 and the arm 10 are rotatable relative to each other about rotation axes parallel to the arm rotation axis 70, and the support unit 15 and the secondary link 510 are rotatable relative to each other about rotation axes parallel to the arm rotation axis 70. The length of the link of the arm 10 connecting between the chassis 2 and the support unit 15 and the length of the link of the secondary link 510 are equal to each other. That is, in the moving body 501, the arm 10, the secondary link 510, and the support unit 15 are connected to form a parallel link.

[0097] In addition, beam-shaped sub-links 516 are provided above the left and right sub-arms 416. The sub-links 516 are supported by the chassis 2 so as to be rotatable about rotation axes parallel to the arm rotation axes 70 of the sub-arms 416. In addition, the support parts 15 that support the rear wheels 51 are connected to the rear ends of the sub-arms 416 and the rear ends of the sub-links 516. In such a support structure for the rear wheels 51, as in the support structure for the front wheels 52 described above, the sub-arms 416, the sub-links 516, and the support parts 15 are connected to form a parallel link.

[0098] As described above, in the second modification, both the rear wheels 51 and the front wheels 52 are supported by a support structure that forms a parallel link. Therefore, even when the arm 10 or the sub-arm 416 rotates, the attitude of the steering shaft 64 of each wheel 50 does not change. Therefore, even if the rotation angle of the arm 10 increases, it is possible to prevent the load on the steering shaft 64, the steering actuator 63, etc. from increasing. Furthermore, even if the rotation angle of the arm 10, etc., or the steering angle of each wheel 50 changes, the angle between the center plane of each wheel 50 and the road surface R remains approximately perpendicular. Therefore, it is possible to always maintain a constant contact state of each wheel 50 with the road surface R.

[0099] In the second modification, only one of rear wheel 51 and front wheel 52 may be supported by a support structure forming a parallel link, and the other may be supported by a support structure similar to that of the above-described embodiment.

[0100] (others)

[0101] The present invention is not limited to the above-described embodiment, and various modifications are possible, and these modifications are also included within the scope of the present invention.

[0102] For example, the arm rotation unit may use one actuator to rotate the left and right arms in unison, in which case it may be configured to use a clutch, a speed reducer, or the like to rotate the left and right arms independently of each other.

[0103] The third wheel may be steerable. Alternatively, the third wheel may be a wheel (a driven wheel) that is not driven by a drive actuator. In this case, the third wheel may be supported so as to be rotatable around an axis different from the axle in response to an external force, for example, like a swivel caster.

[0104] The moving body may be configured to overcome a step even when moving in a diagonal direction, for example. For example, the rotation angle of the arm relative to the chassis may be made different on the left and right sides so that the wheel closest to the step being climbed is lifted off the ground, and the wheel in question rests on the step.

[0105] An embodiment may be configured by appropriately combining the respective configurations according to the above-described embodiments. For example, the configurations are not limited to those of the above-described embodiments, and each component of the above-described embodiments may be appropriately replaced or combined with a component of another embodiment. Furthermore, some components or functions may be omitted from the above-described embodiments.

[0106] The structure of the moving body as described above can be widely used, for example, as an undercarriage device for an indoor / outdoor transport robot or a mobile work robot with a robot arm. [Industrial Applicability]

[0107] As described above, the moving body according to the present invention can have a simple structure, can move over steps in multiple directions, and is useful as a moving body, etc. [Explanation of symbols]

[0108] 1,401,501 Moving body, 2 Chassis, 10 Arm, 15 Support part, 51 Rear wheel (first wheel), 52 Front wheel (second wheel), 53 Third wheel, 61 Drive actuator, 63 Steering actuator, 64 Steering shaft, 70 Arm rotation shaft, 71 Arm rotation part, 416 Sub-arm, 510 Sub-link

Claims

1. The chassis and two arms arranged on either side of the chassis so as to be aligned along a horizontal second direction perpendicular to a horizontal first direction, with the horizontal first direction being a longitudinal direction, and supported by the chassis so as to be rotatable about an arm rotation axis; two first wheels arranged on both sides of the chassis so as to be aligned along the second direction and each rotatable around a steering axis; two second wheels supported rotatably about a steering shaft at positions of each arm that are farther from the first wheel than the arm rotation shaft in the first direction; two third wheels supported at positions of each arm closer to the first wheel than the arm rotation shaft in the first direction, and each third wheel is not configured to be steerable; an arm rotation unit that rotates the arm relative to the chassis; a drive actuator provided corresponding to each of the first wheel and the second wheel, the drive actuator rotating the corresponding wheel around an axle; a steering actuator provided to correspond to each of the first wheel and the second wheel, and configured to rotate the corresponding wheel around the steering axis; a moving body, wherein the third wheel can be switched between a grounded state and a non-grounded state by operation of the arm rotation unit.

2. an arm rotation axis of the arm is substantially parallel to the second direction; The moving body according to claim 1 , wherein the third wheel is held by the arm such that an axle of the third wheel is substantially parallel to the second direction.

3. The moving body according to claim 1 or 2, further comprising a drive actuator provided in correspondence with each of the third wheels.

4. the first direction is a longitudinal direction, and two sub-arms are arranged on both sides of the chassis so as to be aligned along the second direction, and are supported by the chassis so as to be rotatable relative to the chassis; The moving body according to claim 1 , wherein the first wheel is supported by the sub-arm.

5. a sub-link supported by the chassis so as to be rotatable about a rotation axis parallel to the arm rotation axis of the arm; a support portion connected to a portion of the arm and a portion of the sub-link and supporting the second wheel; 5. The moving body according to claim 1, wherein the arm, the sub-link corresponding to the arm, and the support portion are connected to form a parallel link.

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