Mobile System

Abstract

To materialize a moving system capable of moving on a route whose inclination angle is large.SOLUTION: A moving robot 200 in accordance with an embodiment of the present disclosure includes wheels capable of swiveling around a steering shaft 140 extending in a vertical direction. The steering shaft 140 is located at a position different from a grounding point 30 of a wheel 120 when seen from above the moving robot 200. The moving robot 200 includes a control unit 170 that implements control of swiveling the wheels around the steering shaft 140 so that the moving robot 200 can move on an inclined route with the grounding point 30 located at a higher position with respect to the steering shaft 140.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to mobile systems. [Background technology]

[0002] Patent Document 1 discloses a vehicle having an axle and a steering axle, the axle being disposed offset from the steering axle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7198445 Summary of the Invention [Problem to be solved by the invention]

[0004] When the vehicle travels on a route with a large inclination angle, gravity may cause the wheels to rotate around the steering axis, which may prevent the vehicle from moving.

[0005] The present disclosure has been made in consideration of such problems, and provides a mobile system capable of moving on a route with a large inclination angle. [Means for solving the problem]

[0006] A mobile system according to one aspect of the present disclosure includes: A mobility system having wheels that can turn around a steering axis extending in a vertical direction, When viewed from above the moving system, the steering shaft is provided at a position different from the ground contact points of the wheels, a control unit that controls the wheels to turn around the steering axis so that the mobile system moves on an inclined path with the ground contact point positioned at a high position relative to the steering axis; Equipped with. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to realize a mobile system capable of moving on a route with a large inclination angle. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 10 is an explanatory diagram showing the underside of a mobile robot according to a reference example. [Figure 2] 10A and 10B are explanatory diagrams showing the operation of a wheel according to a reference example. [Figure 3] FIG. 10 is an explanatory diagram showing a state in which the mobile robot according to the reference example moves on an inclined surface. [Figure 4] 1 is a block diagram showing the configuration of a mobile robot according to a first embodiment. [Figure 5] FIG. 2 is an explanatory diagram showing a state in which the mobile robot according to the first embodiment moves on an inclined surface. [Figure 6] FIG. 10 is an explanatory diagram showing a state in which a mobile robot according to a modification of the first embodiment moves on an inclined surface. DETAILED DESCRIPTION OF THE INVENTION

[0009] Reference example A mobile robot 100 according to a reference example will be described with reference to Fig. 1. Fig. 1 is an explanatory diagram showing the underside of the mobile robot 100. The mobile robot 100 includes a body 110, wheels 120, an axle 130, and a steering shaft 140.

[0010] The main body 110 houses a motor (not shown) that drives the wheels 120, a control device that sends a control signal to the motor, and the like. The main body 110 may further include a storage section that stores luggage to be transported by the mobile robot 100. The mobile robot 100 may be a transport robot.

[0011] The wheels 120 are provided on the left and right sides of the underside of the main body 110. Each wheel 120 is journaled to the main body 110 so as to be rotatable around a steering shaft 140. The wheels 120 are supported, for example, by a support member 11 that rotates around the steering shaft 140. The wheels 120 are rotatable around an axle 130. The wheels 120 may be active casters that are driven to swivel around the steering shaft 140 and also driven to rotate around the axle 130.

[0012] The axle 130 extends horizontally. A driving force may be transmitted to the axle 130 from a driving mechanism (not shown), causing the wheel 120 to rotate.

[0013] The steering shaft 140 extends in the vertical direction. The axle 130 is arranged offset from the steering shaft 140 in the horizontal direction perpendicular to the axial direction of the axle 130. Therefore, when viewed from above the mobile robot 100, the steering shaft 140 is provided at a position different from the ground contact point of the wheels 120. The wheels 120 may turn by transmitting a driving force to the steering shaft 140 from a driving mechanism (not shown).

[0014] The mobile robot 100 may include multiple motors and a drive mechanism (not shown) that transmits the rotational force of the multiple motors to the axle 130 and the steering shaft 140. The rotational drive around the axle 130 and the turning drive around the steering shaft 140 may be performed independently, or an interference drive may be performed in which the rotational drive and the turning drive interfere with each other.

[0015] The arrows show an example of the movement direction of the mobile robot 100. When the mobile robot 100 moves in a mode where the axle 130 is located behind the steering shaft 140 in the movement direction (called push mode), the mobile robot 100 can move in all directions, but when the mobile robot 100 moves in a mode where the axle 130 is located ahead of the steering shaft 140 in the movement direction (called pull mode), the mobile robot 100 cannot move in all directions. For this reason, the wheels 120 and axle 130 are usually located behind the steering shaft 140 in the movement direction.

[0016] With reference to FIG. 2, the inability of the mobile robot 100 traveling in pull mode to move in an omnidirectional manner will be specifically described. When the mobile robot 100 traveling in pull mode moves to the right in FIG. 2, the wheel 120 needs to be rotated around the steering shaft 140 so that the wheel 120 is positioned on the right side of the steering shaft 140. When the wheel 120 is rotated around the steering shaft 140, the wheel 120 and the steering shaft 140 move to the left, as indicated by the short arrow. In other words, when the mobile robot 100 traveling in pull mode moves to the right, it needs to move to the left once and then move to the right, as indicated by the long arrow. Thus, the mobile robot 100 traveling in pull mode is unable to move in an omnidirectional manner (also called in-place movement).

[0017] Specific problems found by the inventors regarding the mobile robot 100 according to the comparative example will be described with reference to Figure 3. Reference numeral 180 denotes a driven caster provided on the mobile robot 100. The driven caster 180 may be rotatably supported on the main body 110. The mobile robot 100 is climbing an inclined surface 20 in pull mode, and the contact point 30 of the wheel 120 is located at a low position relative to the steering axis 140.

[0018] When the mobile robot 100 climbs an inclined surface 20, the rotation angle of the wheels 120 around the steering axis 140 may exceed a predetermined value due to the influence of gravity, etc. In this case, the mobile robot 100 becomes unsteerable due to insufficient torque. In particular, when the driving force that rotates the wheels around the axles 130 and the driving force that rotates the wheels 120 around the steering axis 140 (also called steering force) are generated by an interference drive mechanism, the steering force alone cannot be increased, and the mobile robot 100 is likely to become unsteerable. Therefore, the first embodiment realizes a mobile system that can move on a route with a large inclination angle.

[0019] Embodiment 1 The mobile system according to the first embodiment will be described below, focusing on the differences from the mobile robot 100 according to the comparative example. The same components are given the same reference numerals, and the description will be omitted as appropriate.

[0020] The mobile system according to the first embodiment includes a mobile robot 200. The mobile system according to the first embodiment may further include a server that controls the movement of the mobile robot 200. The functions of the mobile system may be provided on the mobile robot 200 side or on the server side. However, a mobile system that does not include a server and in which processing is completed within the mobile robot 200 may also be included in the mobile system according to the first embodiment. The following description will focus on the case where the functions of the mobile system are provided on the mobile robot 200 side.

[0021] FIG. 4 is a block diagram showing the configuration of the mobile robot 200 according to the first embodiment. The mobile robot 200 includes a main body 110, wheels 120, axles 130, a steering shaft 140, a drive unit 150, a memory unit 160, and a control unit 170. The mobile robot 200 may further include a driven caster (not shown). The driven caster may also be configured to be rotatable around a steering shaft extending vertically, and the axle of the driven caster may be offset horizontally perpendicular to the turning axis. The driven caster may also be an omniwheel.

[0022] The drive unit 150 includes two motors 151. The rotation of one of the two motors 151 may be transmitted to the axle 130, and the rotation of the other of the two motors 151 may be transmitted to the steering shaft 140. Alternatively, the drive unit 150 may be an interference drive mechanism configured such that the two motors 151 rotate simultaneously to rotate the wheels 120 around the axle 130, and the two motors 151 rotate simultaneously to turn the wheels 120 around the steering shaft 140. The drive unit 150 rotates the axle 130 and the steering shaft 140 based on a control signal generated by the control unit 170.

[0023] The storage unit 160 is a storage device such as a hard disk, a flash memory, etc. The storage unit 160 may include a volatile storage device such as a RAM (Random Access Memory) that is a storage area for temporarily storing information.

[0024] The storage unit 160 stores map information 161. The map information 161 may be information previously stored in the storage unit 160, or may be information received from a server. The map information 161 indicates the positions of inclined paths (e.g., slopes and steps) that exist in the movement area of ​​the mobile robot 200. The map information 161 may further include information indicating the inclination direction and inclination angle of the inclined path.

[0025] The control unit 170 includes a processor and a memory (not shown). The control unit 170 loads a program (not shown) into the memory and executes it. As a result, the control unit 170 performs control to rotate the wheels 120 around the steering shaft 140 so that the mobile robot 200 moves on an inclined path with the ground contact points of the wheels 120 positioned at a high position relative to the steering shaft 140. Specifically, the control unit 170 includes a detection unit 171, a determination unit 172, a switching unit 173, and a movement control unit 174.

[0026] The detection unit 171 detects that the mobile robot 200 is entering an inclined path based on the map information 161. The detection unit 171 may acquire information about the position of the mobile robot 200 based on output results of sensors (e.g., cameras, radar, LIDAR), GPS (Global Positioning System) information, etc. The detection unit 171 may determine whether the mobile robot 200 is entering an inclined path based on, for example, the position information of the mobile robot 200, information indicating the position of an inclined path (e.g., a slope), and information indicating the movement path of the mobile robot 200. The path of the mobile robot 200 may be generated by the mobile robot 200 itself, or may be generated by a server provided external to the mobile robot 200.

[0027] When the mobile robot 200 enters an inclined path, the determination unit 172 determines whether or not it is necessary to perform an operation of turning the wheels 120 around the steering axis (referred to as a turning operation). For example, when the mobile robot 200 enters an inclined path with an inclination angle equal to or greater than a predetermined value, the determination unit 172 may determine that it is necessary to turn the wheels 120 around the steering axis 140, and otherwise determine that it is not necessary to turn the wheels 120 around the steering axis 140. For example, when it is necessary to move laterally on an inclined surface with a small inclination angle, it may be determined that it is not necessary to perform a turning operation. Note that the determination unit 172 may simply make a determination based on whether or not the inclination angle is positive, i.e., whether or not the inclined path is an uphill slope.

[0028] If the determination result of the determination unit 172 is affirmative, the switching unit 173 switches the movement mode of the mobile robot 200 from the push mode to the pull mode. When the movement mode is the push mode, the ground contact points of the wheels 120 are located forward of the steering shaft 140 in the direction of movement. When the movement mode is the pull mode, the ground contact points of the wheels 120 are located rearward of the steering shaft 140 in the direction of movement. The switching unit 173 may switch the movement mode of the mobile robot 200 from the pull mode to the push mode after the mobile robot 200 has finished moving on the inclined path.

[0029] The movement control unit 174 generates a control signal and transmits the control signal to the drive unit 150. The control signal controls the rotation speed of the wheels 120 around the axles 130 and the turning speed of the wheels 120 around the steering shaft 140. In this way, the movement control unit 174 controls the movement of the mobile robot 200. The movement control unit 174 moves the mobile robot 200 along a specified movement path in accordance with the movement mode switched by the switching unit 173. Therefore, when the determination result of the determination unit 172 is positive, the movement control unit 174 turns the wheels 120 around the steering shaft 140 by a predetermined amount (e.g., 180°) and then moves on the inclined path.

[0030] The control unit 170 does not need to include all of the detection unit 171, the determination unit 172, the switching unit 173, and the movement control unit 174. For example, the control unit 170 does not need to include the determination unit 172. In this case, the control unit 170 may perform a turning operation in accordance with the detection result of the detection unit 171.

[0031] FIG. 5 is an explanatory diagram showing the mobile robot 200 moving on the inclined surface 20. When the mobile robot 200 enters the inclined surface 20, the movement mode is switched from the push mode to the pull mode. The mobile robot 200 is climbing the inclined surface 20 in the pull mode, and the contact point 30 is located at a high position relative to the steering axis 140. When the mobile robot 200 climbs the inclined surface 20 in the pull mode, the state of the mobile robot 200 is stable and the mobile robot 200 is unlikely to lose balance. Therefore, the mobile robot 200 can move on an inclined path with a large inclination angle.

[0032] The mobile robot 200 according to the first embodiment can move on an inclined path with a large inclination angle.

[0033] Variations Next, a mobile robot 200a according to a modification of the first embodiment will be described. The mobile robot 200a is a specific example of the mobile robot 200.

[0034] The control unit 170 of the mobile robot 200a further has a function of changing the orientation of the main body 110 relative to the direction of movement based on the position of the center of gravity. The control unit 170 may also have a function of calculating the position of the center of gravity of the mobile robot 200a based on the weight of a load carried on the mobile robot 200a. Information indicating the weight of the load may be received from a server (not shown). When the position where the load is carried is fixed, the position of the center of gravity of the mobile robot 200 can be calculated based on the weight of the load.

[0035] Specifically, the mobile robot 200a determines whether the center of gravity of the mobile robot 200a is located forward of the steering shaft 140. This determination may be made when the determination result of the above-mentioned determination unit 172 is positive. Furthermore, the turning operation described above may be performed taking into account the result of the determination regarding the center of gravity. If the center of gravity is located forward of the steering shaft 140, the mobile robot 200a moves backward of the main body 110 when moving along an inclined path that is an uphill slope.

[0036] 6 is an explanatory diagram showing the mobile robot 200a moving on the inclined surface 20. The mobile robot 200a changes the orientation of the main body 110 so that the position of the center of gravity G of the mobile robot 200a is located behind the steering shaft 140 in the direction of movement, and then enters the inclined surface 20. The center of gravity G, the steering shaft 140, and the ground contact points 30 of the wheels 120 are aligned along the direction of movement of the mobile robot 200a.

[0037] The mobile robot 200a according to the modification of the first embodiment climbs an upward gradient with the center of gravity positioned behind the steering shaft 140 in the direction of movement, thereby improving the stability of the mobile robot 200a.

[0038] The mobile system does not need to have all of its functional elements integrated into the mobile robot 200 or the like. For example, the functions of the detection unit 171 and the determination unit 172 may be performed by a calculation unit included in a server connected to the mobile robot 200 or the like via a network. In this case, the server transmits the determination results to the mobile robot 200. The map information 161 may also be stored in the server. In this way, the mobile system may be configured to include a server and the mobile robot 200. The above-mentioned processor and memory may be located in the server, or in both the mobile robot 200 and the server.

[0039] The above-mentioned programs include instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions. The programs may be stored on a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable medium or tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disc (DVD), Blu-ray® disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The programs may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0040] The present disclosure is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the present disclosure. [Explanation of symbols]

[0041] 100, 200, 200a Mobile Robot 110 Main Unit 120 wheels 130 axles 140 Steering shaft 150 Drive unit 151 Motor 160 Storage section 161 Map Information 170 Control Unit 171 Detection unit 172 Judgment section 173 Switching section 174 Movement control unit 180 Follower caster 11 Support member 20 Slope 30 Grounding point G center of gravity

Claims

1. A mobility system having wheels that can turn around a steering axis extending in a vertical direction, When viewed from above the moving system, the steering shaft is provided at a position different from the ground contact points of the wheels, a control unit that performs control to turn the wheels around the steering axis so that the mobile system moves on an inclined path with the ground contact point positioned at a high position relative to the steering axis; A mobile system equipped with

2. The control unit a detection unit that detects that the mobile system is entering the inclined path based on map information; a determination unit that determines whether or not a turning operation for turning the wheels around the steering axis is necessary when the mobile system enters the inclined path; The mobile system of claim 1 , comprising:

3. The control unit a switching unit that switches the travel mode of the travel system to a pull mode in which the ground contact point is located forward of the steering axis in the travel direction when the determination result of the determining unit is affirmative; The mobile system of claim 2 , comprising:

4. When the center of gravity of the mobile system is located forward of the steering axis, the mobile system moves backward when moving on the inclined path with an uphill gradient. A mobile system according to claim 1 or 2.

5. 3. The transportation system according to claim 1, further comprising an interference drive mechanism that rotates the wheels about the axles and turns the wheels about the steering axes.

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