Mobile

Abstract

To provide a movable body capable of moving in a multi direction.To provide a movable body which can move in multiple directions, using a simplified structure unlike conventional movable bodies.SOLUTION: A movable body comprises: a chassis 2; at least three wheels 50 which are arranged to be aligned in a circumferential direction around the chassis 2; at least three drive actuators 61 which are provided so as to correspond to the wheels 50, respectively, and rotate the corresponding wheels 50 around axles, respectively; a steering actuator 64 for steering the wheels 50; a steering mechanism 65 which has an input member 161 moving according to operation of the steering actuator 64, and an output member 166 which is configured to be linked with displacement of the input member 161; and at least three transmission mechanisms 67 for rotating the corresponding wheel 50 around a steering axis, according to operation of the corresponding output member 166. As configured with the at least three wheels 50 being steered synchronously according to the operation of the steering actuator 64, the movable body 1 is movable in multi directions using a simplified structure.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] BACKGROUND ART Conventionally, there have been proposed configurations of mobile bodies having multiple wheels and used for various purposes. For example, such mobile body configurations may be used in robots capable of autonomous travel.

[0003] An example of a moving body configured to be movable in all directions is that described in Patent Document 1 below, which has multiple moving parts arranged at the bottom of a base with support shafts that can move back and forth.

[0004] The following Patent Document 2 describes the configuration of a synchronized steering vehicle body that aims to directly achieve synchronized steering between the wheels and the cab without the need for a differential. In this synchronized steering vehicle body, multiple wheels and the cab are linked together using gears or chains and sprockets, etc.

[0005] Incidentally, Patent Document 3 listed below describes the configuration of a moving body that is configured to overcome steps by using arms that support the wheels to raise and lower the drive mechanism of the wheels. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-188013 [Patent Document 2] Special Publication No. 2019-521914 [Patent Document 3] Special Publication No. 2018-535875 Summary of the Invention [Problem to be solved by the invention]

[0007] Mobile bodies having structures such as those described in Patent Documents 1 and 2 are capable of moving in all directions, but have a complex overall structure. Also, a mobile body using wheels such as that described in Patent Document 3 is capable of moving in a predetermined direction according to the orientation of the wheels, but is not capable of moving in multiple directions relative to the orientation of the chassis.

[0008] An object of the present invention is to provide a moving body that is capable of moving in multiple directions using a simple configuration. [Means for solving the problem]

[0009] The mobile body of the first invention comprises a chassis, at least three wheels each arranged in a circumferential direction around the chassis in a plan view, supported relative to the chassis via a support portion, and rotatable about a steering axis relative to the support portion, at least three drive actuators provided corresponding to each of the wheels and rotating the corresponding wheel about an axle, a steering actuator for steering the wheels, a steering mechanism having an input member that moves in response to the operation of the steering actuator and an output member configured to be linked to the operation of the input member, and at least three transmission mechanisms provided corresponding to each of the wheels and rotating the corresponding wheel about the steering axis in response to the operation of the corresponding output member, and configured so that each wheel is steered synchronously in response to the operation of the steering actuator.

[0010] With this configuration, it is possible to make the device movable in multiple directions with a simple configuration.

[0011] In addition, in contrast to the first invention, the mobile body of the second invention is a mobile body that further comprises at least three arms that are arranged in a circumferential row around the chassis in a plan view, each of which is rotatable up and down and supported on the chassis so as to protrude outward from the outer peripheral surface of the chassis, and arm rotation units that are provided corresponding to each of the arms and are capable of rotating one arm relative to the chassis, and a support unit is provided on each of the arms, and the wheels are supported by the arms at a position spaced outward from the outer peripheral surface of the chassis.

[0012] With this configuration, a moving body that can move over steps in multiple directions can be realized with a simple configuration.

[0013] Furthermore, the movable body of the third invention is a movable body in which, compared to the first or second invention, each of the arms includes a first link and a second link that is approximately parallel to the first link, and the support portion is connected to the first link and the second link so as to form a parallel link.

[0014] This simple configuration realizes a mobile body that can move over steps in multiple directions.

[0015] Furthermore, the mobile body of the fourth invention is a mobile body in which, compared to any of the first to third inventions, the steering mechanism has an input shaft that rotates in response to the operation of the steering actuator and output shafts the number of which is equal to the number of wheels that rotate in response to the rotation of the input shaft, and each of the transmission mechanisms rotates in response to the corresponding output shaft, and transmits the torque of each output shaft as torque that rotates each of at least three wheels around the steering axis.

[0016] This configuration ensures a wide steerable range for each wheel.

[0017] Furthermore, a moving body according to a fifth aspect of the present invention is a moving body according to any one of the first to fourth aspects of the present invention, wherein the transmission mechanism has a constant velocity joint.

[0018] This configuration allows the wheels to be steered more reliably and synchronously. [Effects of the Invention]

[0019] According to the present invention, a moving body can be made movable in multiple directions using a simple configuration. [Brief explanation of the drawings]

[0020] [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] Plan view of the same vehicle [Figure 3] Cross section of line AA in Figure 2 [Figure 4] Side view of steering mechanism [Figure 5] Cross section of line BB in Figure 4 [Figure 6] Cross section of line CC in Figure 4 [Figure 7] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] 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.

[0022] In the following, for the convenience of explaining the structure of the moving body, directions may be indicated based on the state in which the moving body is in contact with a horizontal road surface. That is, the direction perpendicular to the road surface may be referred to as the up-down direction. Furthermore, the direction passing through the center of the moving body (not necessarily the exact center) in a plan view may be referred to as the radial direction. The direction along an arc centered on the center of the moving body may be referred to as the circumferential direction. The indication of each direction in this manner is done solely for the convenience of explanation and does not limit the orientation, posture, etc. of the moving body of the present invention when in use.

[0023] (Embodiment)

[0024] In this embodiment, the moving body has three sets of arms to which wheels are attached that protrude outward from the outer circumferential surface of the chassis. Each wheel is configured to be steered synchronously by operating a steering mechanism with one steering actuator. The arms are attached to the chassis so as to be rotatable up and down, and are formed as parallel links, but are not limited to this. The moving body 1 configured in this manner will be described below.

[0025] Fig. 1 is a perspective view showing the configuration of a moving body 1 according to an example of the present embodiment, Fig. 2 is a plan view of the moving body 1, and Fig. 3 is a cross-sectional view taken along line AA in Fig. 2.

[0026] In the following description, illustrations of the detailed configuration of the moving body 1 are omitted. For example, the structure of the chassis 2 other than the parts related to wheel suspension and steering may be set appropriately depending on the use of the moving body 1, etc.

[0027] The moving body 1 includes a chassis 2, three arms 11, 21, and 31 (hereinafter, these may be collectively referred to as arms 10 without distinction), three wheels 51, 52, and 53 (hereinafter, these may be collectively referred to as wheels 50 without distinction), three drive actuators 61, an arm rotation unit 71, and three training wheels 81. The moving body 1 also includes one steering actuator 64, a steering mechanism 65, and a transmission mechanism 67.

[0028] The mobile object 1 is typically placed on a substantially flat road surface and is capable of moving on the road surface. The mobile object 1 includes, for example, a control unit (not shown) mounted on the chassis 2 (which may be configured, for example, by a computer or an electric circuit), a sensor unit for detecting the surrounding conditions, and a battery used as a power source for each unit. The mobile object 1 is configured to be able to autonomously move in multiple directions on the road surface 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. Here, being able to move in multiple directions means being able to move in various directions, such as forward, backward, left, right, and diagonally, while maintaining the orientation of the chassis 2 in a predetermined direction. 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 by configuring various actuators to function based on a preset program, sequence, or the like. Alternatively, the mobile object 1 may be able to move on the road surface by receiving instructions from the outside to operate each actuator.

[0029] 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 a polygonal shape in a plan view. In a plan view, the chassis 2 has a shape that can be roughly described as a triangle. More specifically, the side surfaces to which the three arms 10 are attached form an angle of roughly 60 degrees, as will be described later. The chassis 2 may have a shape that is partially or entirely rounded.

[0030] The arm 10 is a component that is arranged, for example, linearly in a plan view. The arm 10 is arranged so as to extend substantially horizontally radially outward from the chassis 2 under normal conditions (for example, when moving on a horizontal road surface). In a plan view, the arms 11, 21, and 31 are arranged in this order in the circumferential direction around the chassis 2 in a clockwise direction. In this embodiment, each of the three arms 10 is configured to have substantially the same shape and dimensions. Furthermore, each of the three arms 10 is arranged so as to form an angle of approximately 120 degrees with the other two arms 10 in a plan view. That is, in a plan view, the angle between the arm 11 and the arm 21, the angle between the arm 21 and the arm 31, and the angle between the arm 31 and the arm 21 are all configured so as to be approximately 120 degrees. The three arms 10 are arranged on three side portions of the chassis 2 that roughly form a triangle in a plan view as described above. In this embodiment, the arms 10 are supported by the chassis 2 so as to protrude outward from the outer circumferential surface of the chassis 2. That is, the arms 10 are provided so that their longitudinal direction is the direction in which they protrude radially outward from the outer circumferential surface of the chassis 2, i.e., the radial direction. However, the length of each arm 10, its relative positions, the direction in which they protrude outward from the chassis 2, and the like are not limited to this.

[0031] In this embodiment, the arm 10 is composed of a first link 111, a second link 112 disposed on the first link 111 and substantially parallel to the first link 111, and a support portion 115 that supports the wheel 50. The tip of the first link 111 and the tip of the second link 112 are attached to the support portion 115, and a parallel link mechanism is configured using the two equal-length links 111, 112. It can be said that the wheel 50 is supported by the chassis 2 together with the drive actuator 61 via the support portion 115. It can also be said that the wheel 50 is supported by the chassis 2 via the arm 10. The wheel 50 is supported by the support portion 115 so as to be rotatable about a substantially vertical steering axis 63. It is also possible to interpret the first link 111 and the second link 112 themselves as arms.

[0032] Furthermore, in this embodiment, each arm 10 is supported with respect to the chassis 2 so as to be rotatable with respect to the chassis 2. Here, "the arm 10 is rotatable with respect to the chassis 2" means that the two links 111, 112 are each rotatable around an arm rotation axis with respect to the chassis 2. That is, the first link 111 is rotatable around the arm rotation axis with respect to the chassis 2 by the arm rotation unit 71. Also, the second link 112 is rotatable around the arm rotation axis with respect to the chassis 2. Both the first link 111 and the second link 112 are configured to rotate around their respective arm rotation axes with respect to the chassis 2 by the driving force of the arm rotation unit 71.

[0033] In this embodiment, each arm rotation axis passes near the radially inner end of each arm 10 in a plan view. Each arm rotation axis is an axis arranged approximately horizontally. In each arm, the arm rotation axes of the two links 111, 112 are parallel to each other. The two links 111, 112 can rotate up and down relative to the chassis 2 around the arm rotation axis from a state in which their longitudinal direction is approximately horizontal. In other words, the arm 10 can rotate with respect to the chassis 2 so that portions away from each arm rotation axis are displaced up and down. It may also be said that the arm 10 can oscillate, or that the arm 10 can swing.

[0034] Since the arm 10 is a parallel link, the support portion 115 is configured to be displaced to the upper limit while maintaining its posture as the first link 111 and the second link 112 rotate relative to the chassis 2. In this way, the angle of the steering shaft 63 of the wheel 50 does not change before and after the arm 10 rotates. Therefore, even if the rotation angle of the arm 10 becomes larger than normal, it is possible to prevent the load on the steering shaft 63, the steering actuator 64, etc. from increasing.

[0035] In this embodiment, in a plan view, the arm rotation axis of each of the three arms 10 is approximately perpendicular to the longitudinal direction of the respective arm 10. Each arm rotation axis is disposed so as to form an angle of approximately 60 degrees with the arm rotation axes of the other two arms 10 in a plan view. In addition, in a plan view, a line that is perpendicular to the arm rotation axis of each of the three arms 10 and passes through a wheel 50 (described later) is configured to pass through a common point. Note that "each arm rotation axis passing through a common point" can be interpreted roughly, and is an expression that allows for a state in which the intersections of the lines of two arms 10 are offset from each other in the strict sense. The three arms 10 are disposed so as to protrude radially from the chassis 2 when viewed from the center of the chassis 2.

[0036] Note that first link 111 and second link 112 may have a shape other than a straight line, such as being curved or being a plate-like or A-shaped member in a plan view. Arm 10 does not have to be a parallel link as described above, and may be roughly formed of a single member, such as a beam-like member, a curved member, or a plate-like or A-shaped member in a plan view. In this case, it is sufficient that support portion 115 is provided at the tip end of arm 10, and support portion 117 supports wheel 50 so as to be rotatable about steering shaft 63.

[0037] The wheels 50 are provided on each of the three arms 10 at positions spaced outward from the outer circumferential surface of the chassis 2. In this embodiment, the wheels 50 are supported by support portions 115 provided near the radially outer ends (tips) of each of the three arms 10.

[0038] More specifically, a wheel 51 is disposed at the tip of the arm 11, a wheel 52 is disposed at the tip of the arm 21, and a wheel 53 is disposed at the tip of the arm 31. The wheels 51, 52, and 53 are disposed so as to line up in this order in a clockwise direction throughout the entire moving body 1. The distance between each wheel 50 and the center of the chassis 2 is roughly equal. In other words, the wheels 50 supported by each of the three arms 10 are located on a circumference with a common center in a plan view. Note that the positions of the wheels 50 are not limited to this and may be changed depending on the length of the arms 10, the number of arms 10, and the shape of the chassis 2. Furthermore, in addition to one wheel 50, each arm 10 may be provided with a different wheel, such as a training wheel.

[0039] The drive actuators 61 are provided to correspond to the wheels 50 of the three arms 10, respectively. The drive actuators 61 are configured to rotate the corresponding wheels 50 about the axles, thereby moving the moving body 1. For example, the control unit controls the operation of each drive actuator 61, thereby moving the moving body 1. Furthermore, for example, the moving body 1 may be movable by each drive actuator 61 being driven in response to an external command.

[0040] In this embodiment, 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 wheels 50, i.e., the number of rotations of the axles, 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) that transmits the torque of the motor to the axles. The drive actuator 61 may also have a clutch that allows the wheels 50 to rotate freely.

[0041] The arm rotation units 71 are provided to correspond to at least three arms 10, respectively. Each arm rotation unit 71 is configured to rotate one arm 10 around the arm rotation unit 71 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. Alternatively, for example, the arm rotation unit 71 may be driven in response to an external command, causing the corresponding arm 10 to rotate.

[0042] 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 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.

[0043] The training wheels 81 are arranged so as to be located between the chassis 2 and the road surface. In this embodiment, the training wheels 81 are arranged on the surface of the chassis 2 facing the road surface. The training wheels 81 may be configured to be rotatable around a vertical axis depending on the direction of movement of the movable body 1, like a so-called swivel caster, for example, but are not limited to this. In this embodiment, three training wheels 81 are provided. The three training wheels 81 are arranged on a line that is perpendicular to each arm rotation axis and passes through the center of the chassis 2. As a result, the movable body 1 is configured so that the chassis 2 is stably supported by the one or more training wheels 81 even in a state in which one or more wheels 50 are separated from the road surface or the like. Note that the number and positions of the training wheels 81 are not limited to this and may be one, two, or four or more.

[0044] In this embodiment, the three wheels 51, 52, and 53 are configured to rotate around the respective steering shafts 63 in synchronization with the operation of a single steering actuator 64. The steering actuator 64 is disposed on the chassis 2. The steering actuator 64 is an actuator for steering each of the wheels 50. For example, a control unit controls the operation of the steering actuator 64, causing each of the wheels 50 to rotate around the steering shaft 63 in synchronization with the other wheels. Alternatively, for example, the steering actuator 64 may be driven in response to an external command to perform steering. A specific configuration of a steering system that realizes steering of the three wheels 50 using a single steering actuator 64 will be described later.

[0045] In this embodiment, the steering actuator 64 is an actuator capable of controlling the steering angle of each wheel 50. The steering actuator 64 is, for example, a servo motor or a stepping motor, but is not limited to these. For example, the steering actuator 64 may be an actuator such as a motor that is equipped with an encoder or the like and is capable of controlling its own rotation angle. The steering actuator 64 may also be an actuator such as a motor that is configured to control an output shaft in accordance with a steering angle detected using an encoder provided on at least one wheel 50. The steering actuator 64 may also be one that rotates its output shaft using a hydraulic actuator. The steering actuator 64 may also be configured to include a linear actuator.

[0046] As described above, in the moving body 1, the arms 10, each of which has wheels 50 attached to its tip and which can be displaced up and down relative to the chassis 2, are arranged to protrude radially from the chassis 2. Furthermore, each wheel 50 can be rotated by a drive actuator 61 and can be steered synchronously by a single steering actuator 64. Therefore, the moving body 1 has the following capabilities: The moving body 1 can move in multiple directions. Furthermore, when moving in multiple directions, the moving body can overcome steps in those directions. In addition, the moving body 1 can adjust the posture of the chassis 2 by rotating the three arms 10 relative to the chassis 2 while the wheels 50 are in contact with the ground surface. Therefore, it can easily meet the need for transportation with a stable posture, for example.

[0047] When the moving body 1 is to overcome a step in the moving direction, for example, the arm 10 may be rotated relative to the chassis 2 as follows.

[0048] That is, in this embodiment, the movable body 1 can rotate the arms 10 relative to the chassis 2 by the arm rotation unit 71, thereby displacing the wheels 50 supported by the arms 10 up and down relative to the chassis 2. When at least one arm 10 rotates upward, the wheels 50 supported by the arm 10 move upward (float) above the road surface. When one or more arms 10 rotate downward, the chassis 2 is lifted up above the road surface.

[0049] For example, in this embodiment, the movable body 1 moves so that the lifted wheels 50 approach a step that becomes higher in the direction of travel as the arms 10 rotate upward, placing the wheels 50 on the step. Also, the movable body 1 rotates the arms 10 downward, so that the lifted wheels 50 land on the bottom of the step as they pass over a step that becomes lower in the direction of travel. In accordance with this, the movable body 1 rotates each arm 10 up and down, causing the chassis 2 to rise or fall. Depending on the direction of travel of the movable body 1 and the position of the step, the arm 10 to be rotated and its rotation direction are changed as appropriate, thereby performing a series of operations to overcome the step. This enables the movable body 1 to move in multiple directions and overcome steps.

[0050] Next, the configuration of a steering system that realizes steering of the three wheels 50 according to this embodiment will be described. As described above, in the moving body 1, all of the wheels 50 can be rotated by the drive actuators 61, and can be steered in synchronization by one steering actuator 64. This allows the moving body 1 to move in multiple directions depending on the drive state of each wheel 50 (rotation around the axle or rotation around the steering shaft 63). That is, in this embodiment, it can be said that one steering actuator 64 and the drive actuators 61 of each wheel 50 constitute a movement mechanism that moves the moving body 1.

[0051] In this embodiment, the operation of one steering actuator 64 is reflected in the steering of each wheel 50 using a steering mechanism 65 and a transmission mechanism 67. The steering mechanism 65 is disposed, for example, in the central portion of the chassis 2, i.e., at the turning center of the mobile body 1. The transmission mechanisms 67 are provided corresponding to each wheel 50. Each transmission mechanism 67 is configured to connect the steering mechanism 65 and each wheel 50.

[0052] In this embodiment, the steering mechanism 65 is configured to rotate a total of three output members 166 corresponding to each wheel 50 in the same direction in response to the operation of one steering actuator 64. Each transmission mechanism 67 is configured to transmit the torque of the output member 166 as torque that rotates the corresponding wheel 50 around the steering shaft 63.

[0053] Fig. 4 is a side view of the steering mechanism 65. Fig. 5 is a cross-sectional view taken along line BB in Fig. 4. Fig. 6 is a cross-sectional view taken along line CC in Fig. 4.

[0054] In this embodiment, the steering mechanism 65 is a gear box that houses multiple bevel gears. That is, the steering mechanism 65 has an input member 161, an output member 166, a first bevel gear 162, and a second bevel gear 163. Each of these components is attached to a casing 160. The steering actuator 64 is attached to the upper part of the steering mechanism 65, for example.

[0055] One input member 161 is provided. The input member 161 is a rotating shaft that is arranged in parallel in the vertical direction in the central part of the chassis 2. The input member 161 may also be called an input shaft. The input member 161 is rotatably held in the casing 160 using a bearing or the like. The input member 161 is coupled to the output shaft of the steering actuator 64. The output shaft of the steering actuator 64 may also be the input member 161. In other words, the input member 161 is configured to move in response to the operation of the steering actuator 64. It may also be said that the input member 161 rotates in response to the operation of the steering actuator 64.

[0056] Three output members 166 are provided, one for each wheel 50, i.e., one for each arm 10. This number may be greater than the number of wheels 50. The output member 166 is a rotating shaft that is disposed so as to penetrate the side surface of the casing 160 in a substantially horizontal position. The output member 166 may also be referred to as an output shaft. The output member 166 is rotatably held relative to the casing 160 using a bearing or the like. A transmission mechanism 67 is coupled to the output member 166. A coupling 67b or the like is used at the coupling portion between the output member 166 and the transmission mechanism 67, but this is not limiting. For example, they may be directly coupled, or there may be no distinction between the output member 166 and the transmission mechanism 67.

[0057] There is one first bevel gear 162. The first bevel gear 162 is fixed to the input member 161 inside the casing 160. The first bevel gear 162 rotates together with the input member 161. That is, the first bevel gear 162 is interlocked with the input shaft.

[0058] Three second bevel gears 163 are provided, one for each output member 166, i.e., one for each wheel 50. This number may be greater than the number of wheels 50. Each second bevel gear 163 is fixed to a corresponding output member 166 inside the casing 160. That is, the second bevel gears 163 are arranged to rotate together with the corresponding output shaft. Each second bevel gear 163 is arranged to mesh with a first bevel gear 162.

[0059] Since the steering mechanism 65 is configured in this manner, the input member 161 rotates in response to the operation of the steering actuator 64, and each output member 166 rotates in response to the rotation of the input member 161. That is, in this embodiment, the output members 166 are configured to move in conjunction with the operation of the input members 161.

[0060] FIG. 7 is a side cross-sectional view of the moving body 1. As shown in FIG.

[0061] The cross section shown in Fig. 7 is a section that passes through the steering mechanism 65 and the arm 11 and transmission mechanism 67 corresponding to the wheel 51. The upper part of Fig. 7 shows the normal state in which the ground contact portion of the wheel 51 is at the same height as or slightly lower than the ground contact portion of the training wheel 81. The lower part of Fig. 7 shows the state in which the arm 11 has rotated upward from the normal state, causing the wheel 51 to be displaced upward.

[0062] The transmission mechanism 67 forms a torque transmission path from the steering mechanism 65 to the wheels 51. In this embodiment, the transmission mechanism 67 has an external transmission unit 68 located outside the chassis 2 and a coupling 67b located midway along the transmission path. Also in this embodiment, a steering unit 69 is provided on top of the steering shaft 63 of the wheels 50. The steering unit 69 is housed, for example, inside the support unit 115. The steering unit 69 may or may not be interpreted as being included in the transmission mechanism 67.

[0063] Each transmission mechanism 67 is configured to rotate in response to the rotation of the corresponding output member 166. The transmission mechanism 67 has a shaft that transmits torque from inside the chassis 2 to an external transmission unit 68 located outside. The external transmission unit 68 has, for example, two constant velocity joints provided near the chassis 2 and near the wheels 50, and is connected to the steering unit 69. In this embodiment, the external transmission unit 68 is disposed substantially parallel to the links 111, 112, but this is not limited to this. The external transmission unit 68 transmits the torque transmitted from inside the chassis 2 to the steering unit 69. The steering unit 69 has, for example, a structure in which a bevel gear that rotates together with the external transmission unit 68 and a bevel gear that rotates together with the steering shaft 63 mesh with each other. The steering shaft 63 is configured to rotate accordingly as the external transmission unit 68 rotates.

[0064] In this way, each of the transmission mechanisms 67 rotates the corresponding wheel 50 around the steering shaft 63 in response to the operation of the corresponding output member 166. As a result, in the moving body 1, each of the wheels 50 is steered in synchronization in response to the operation of one steering actuator 64.

[0065] The number of teeth of the first gear 162 and the number of teeth of the second gear 163 are set appropriately depending on the configuration of the steering actuator 64, the configuration of the transmission mechanism 67, requirements for steering the wheels 50, etc. The number of teeth of each second gear 163 and the number of teeth of the bevel gear of each steering unit 68 are configured to be the same. This allows the wheels 50 to rotate synchronously.

[0066] Here, the transmission mechanism 67 is provided with an external transmission unit 68 configured using a constant velocity joint. Therefore, even when the arm 1 is displaced up or down from the normal state, for example as shown in the lower part of Fig. 7, torque is transmitted smoothly from the steering mechanism 65 to the steering unit 69, making it possible to operate each wheel 50. Therefore, the movable body 1 can be moved in multiple directions by steering each wheel 50, while rotating the arm 1 to overcome steps.

[0067] As described above, according to this embodiment, the moving body 1 can steer the multiple wheels 50 in synchronization with one steering actuator 64. This simplifies the configuration of the moving body 1, and also simplifies the configuration and control content of the control unit that controls each actuator, etc. Therefore, the moving body 1 can be made movable in multiple directions using a simple configuration.

[0068] Conventionally, many mobile vehicles designed for rough terrain have wheels equipped with a mechanism that allows the wheels to lift. When using such a mechanism, the wheels must be steered independently on each axis using an actuator such as a motor. However, such a complex configuration leads to increased costs.

[0069] In contrast to this, in this embodiment, as described above, the moving body 1 is configured to be able to overcome steps by rotating the arm 1 while moving in multiple directions by steering each wheel 50. Therefore, the moving body 1 that can move in multiple directions and overcome steps can be configured simply.

[0070] The steering mechanism 65 and the transmission mechanism 67 are configured using bevel gears so that the wheels 50 can be steered by the rotation of the transmission mechanism 67. Therefore, a large steerable range for each wheel 50 can be ensured, and the wheels 50 can be moved smoothly in multiple directions while rotating around their axles.

[0071] The steering actuator 64 can be disposed inside the chassis 2. Therefore, even when a steering actuator 64 that has a comparatively poor water resistance is used, the water resistance of the moving body 1 can be maintained at a high level.

[0072] (others)

[0073] 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.

[0074] The transmission mechanism may be, for example, a flexible member such as a wire that can transmit torque. In this case, too, the arm can be rotated up and down while still allowing steering of each wheel.

[0075] Each transmission mechanism may be provided with a clutch that turns on and off the transmission of torque. In this case, by driving the steering actuator while changing the connection state of the clutch corresponding to each wheel, it is possible to steer each wheel to a different steering angle. For example, by setting each wheel to a steering angle that is approximately perpendicular to the radial direction when viewed from the center of the chassis, the moving body 1 can be turned on the spot.

[0076] Furthermore, for example, the steering mechanism and the transmission mechanism may be configured using a link or the like. For example, the steering unit may have a lever provided to protrude radially from the steering shaft, and the transmission mechanism may be configured to steer the wheels by moving the tip of the lever toward or away from the chassis in response to the displacement of an output member. Such a configuration may be configured, for example, by a steering actuator that is a servo motor, a so-called servo horn (an example of an output member) that is linked to the output shaft (an example of an input member) of the steering actuator, and a transmission mechanism that is a link member that connects the servo horn and the lever. In this case, the transmission mechanism may be configured using a wire or the like that pulls the lever toward the chassis, and the steering unit may be configured using a spring or the like that biases the lever to rotate the steering shaft in a direction away from the chassis.

[0077] For example, training wheels may not necessarily be provided. For example, in the above-described embodiment, a contact portion may be provided on the surface of the chassis facing the road surface, which is configured to contact the road surface instead of the wheel when one or more arms rotate upward. In this case, the contact portion may have, for example, a spherical member rotatably held on the chassis, or may be fixed to the chassis and provided so as to slide against the road surface. It is preferable that the contact portion be configured so as to have a small coefficient of friction with the road surface.

[0078] The number of arms is not limited to three, and four or more arms may be provided. In the above-described embodiment, three arms are arranged to form a Y-shape in a plan view, but this is not limiting. For example, four arms may be arranged around the chassis to form an X-shape in a plan view. Increasing the number of arms can improve stability during driving and stability when climbing over obstacles. In this case, by increasing the number of output shafts of the steering mechanism and the number of transmission mechanisms to four, the wheels of each arm can be steered in synchronization.

[0079] 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.

[0080] 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]

[0081] 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]

[0082] 1 moving body, 2 chassis, 10, 11, 21, 31 arm, 50, 51, 52, 53 wheel, 60 moving mechanism, 61 drive actuator, 63 steering shaft, 64 steering actuator, 65 steering mechanism, 67 transmission mechanism, 71 arm rotation part, 111 first link, 112 second link, 115 support part

Claims

1. The chassis and At least three wheels, each of which is arranged in a circumferential direction around the chassis in a plan view, is supported on the chassis via a support portion, and is rotatable around a steering axis relative to the support portion; at least three drive actuators provided corresponding to the wheels, respectively, for rotating the corresponding wheels about their axles; a steering actuator for steering the wheels; a steering mechanism having an input member that moves in response to operation of the steering actuator and an output member configured to move in conjunction with operation of the input member; at least three transmission mechanisms provided corresponding to the wheels, each of which rotates the corresponding wheel around the steering shaft in response to an operation of the corresponding output member; the transmission mechanism has a constant velocity joint, A moving body configured such that the wheels are steered synchronously in response to the operation of the steering actuator.

2. At least three arms are arranged in a circumferential direction around the chassis in a plan view, and each arm is supported by the chassis so as to be rotatable up and down and protrude outward from the outer circumferential surface of the chassis; an arm rotation unit provided to correspond to each of the arms and capable of rotating one of the arms relative to the chassis, The support portion is provided on each of the arms, The moving body according to claim 1 , wherein the wheels are supported by the arms at positions spaced outward from the outer circumferential surface of the chassis.

3. Each of the arms includes a first link and a second link that is substantially parallel to the first link; The moving body according to claim 2 , wherein the support portion is connected to the first link and the second link so as to form a parallel link.

4. the input member is an input shaft that rotates in response to an operation of the steering actuator, the output members are output shafts the number of which corresponds to the number of wheels and which rotate in response to rotation of the input shaft, 4. The moving body according to claim 1, wherein each of the transmission mechanisms rotates in accordance with the corresponding output shaft and transmits torque of each of the output shafts as torque that rotates each of the at least three wheels around the steering axis.

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