Unmanned carrier

Abstract

To provide an unmanned carrier capable of suppressing postural change of a carrier body in switching between a normal travel mode and a sideward travel mode.SOLUTION: An unmanned carrier capable of switching between a normal travel mode in which it can travel straight in a front-rear direction X and a sideward travel mode in which it can travel straight in a right-left direction Y comprises: a plurality of wheels (a left front wheel 3FL and a right front wheel 3FR, and a left rear wheel 3RL and a right rear wheel 3RR); a drive unit which limits rolling of the left front wheel 3FL and left rear wheel 3RL; a steering device which change directions of the plurality of wheels; and a control device. In the switching between the normal travel mode and sideward travel mode, the control device controls the steering device to change the directions of the right front wheel 3FR and left rear wheel 3RL after changing the directions of the left front wheel 3FL and right rear wheel 3RR, and also controls the drive unit to limit rolling of the left rear wheel 3RL when changing the direction of the left front wheel 3FL and right rear wheel 3RR and limit rolling of the left front wheel 3FL when changing the direction of the right front wheel 3FR and left rear wheel 3RL.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an automated guided vehicle capable of switching between a normal running mode and a lateral running mode.

Background Art

[0002] An automated guided vehicle capable of switching between a normal running mode in which it can move straight in the front-rear direction and a lateral running mode in which it can move straight in the left-right direction is known (see, for example, Patent Document 1). The switching between the normal running mode and the lateral running mode is performed by changing the direction of the wheels.

[0003] FIG. 8 illustrates a conventional automated guided vehicle including a vehicle body 102 and a plurality of wheels 103. As shown in FIG. 8(A), in the automated guided vehicle in the normal running mode, the wheels 103 face the front-rear direction X. When switching from the normal running mode to the lateral running mode, as shown in FIG. 8(B), a steering device (not shown) changes the direction of the wheels 103 so that the wheels 103 face the left-right direction Y. At this time, due to the unevenness of the road surface and the grounding state of the wheels 103, there is a problem that the posture of the vehicle body 102 changes as shown in FIG. 8(C). Therefore, as described in Patent Document 1, correcting the posture change of the vehicle body during running has been performed.

[0004] However, when correcting the posture change of the vehicle body during running, if the distance from the start of running after switching between the normal running mode and the lateral running mode to the stop is short, there is a problem that the posture change of the vehicle body cannot be sufficiently corrected.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide an unmanned transport vehicle capable of suppressing a change in the posture of a vehicle body when switching between a normal traveling mode and a lateral traveling mode. [Means for Solving the Problems]

[0007] In order to solve the above problems, an unmanned transport vehicle of the present invention is an unmanned transport vehicle capable of switching between a normal traveling mode in which it can travel straight in the front-rear direction and a lateral traveling mode in which it can travel straight in the left-right direction, and includes a plurality of wheels provided at intervals in the front-rear direction and the left-right direction, a braking device that restricts the rolling of at least two of the wheels, a steering device that changes the directions of the plurality of wheels, and a control device that controls the braking device and the steering device. The control device designates one set of the plurality of wheels as primary steering wheels and another set of the wheels as secondary steering wheels, and when switching between the normal traveling mode and the lateral traveling mode, controls the steering device so as to change the direction of the secondary steering wheels after changing the direction of the primary steering wheels. Further, when changing the direction of the primary steering wheels, the braking device is controlled to restrict the rolling of at least one of the wheels included in the secondary steering wheels, and when changing the direction of the secondary steering wheels, the braking device is controlled to restrict the rolling of at least one of the wheels included in the primary steering wheels.

[0008] Also, the wheels include front wheels and rear wheels provided at intervals in the front-rear direction. The front wheels are composed of a left front wheel and a right front wheel provided at intervals in the left-right direction, and the rear wheels are composed of a left rear wheel and a right rear wheel provided at intervals in the left-right direction. It is preferable that one set of the left front wheel and the right rear wheel and one set of the right front wheel and the left rear wheel include one as the primary steering wheels and the other as the secondary steering wheels.

[0009] Also, it is preferable that the rolling of any one set among one set of the left front wheel and the left rear wheel, one set of the right front wheel and the right rear wheel, one set of the left front wheel and the right front wheel, and one set of the left rear wheel and the right rear wheel is restricted by the braking device.

[0010] Further, it is provided with front wheels and rear wheels that are spaced apart in the front-rear direction as the wheels, the front wheels are composed of a left front wheel and a right front wheel that are spaced apart in the left-right direction, the rear wheels are composed of a left rear wheel and a right rear wheel that are spaced apart in the left-right direction, and it is preferable that one set of the left front wheel and the left rear wheel, one set of the right front wheel and the right rear wheel, one set of the left front wheel and the right front wheel, or one set of the left rear wheel and the right rear wheel is a primary steering wheel.

[0011] Further, it is preferable that the rolling of one of one set of the left front wheel and the right rear wheel and one set of the right front wheel and the left rear wheel is restricted by the braking device.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide an unmanned carrier vehicle that can suppress a change in the posture of the vehicle body when switching between a normal traveling mode and a crab traveling mode.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0014] An embodiment of the present invention will be described with reference to FIGS. 1 to 4. As shown in FIG. 1, the automated guided vehicle 1 according to the present embodiment includes a vehicle body 2, front wheels 3F and rear wheels 3R which are wheels, guidance sensors 4F and 4R for the normal traveling mode, and guidance sensors 5L and 5R for the lateral traveling mode. The automated guided vehicle 1 travels by switching between a normal traveling mode in which it can travel straight in the front-rear direction X and a lateral traveling mode in which it can travel straight in the left-right direction Y.

[0015] The vehicle body 2 is provided with a loading platform (both not shown) equipped with a transfer device. The transfer device is constituted by, for example, a belt conveyor or a roller conveyor driven by a handling motor, and is controlled by a control device 8 (see FIG. 2) described later.

[0016] The front wheels 3F and the rear wheels 3R are provided at intervals in the front-rear direction X. The front wheels 3F are constituted by a left front wheel 3FL and a right front wheel 3FR provided at intervals in the left-right direction Y. The rear wheels 3R are constituted by a left rear wheel 3RL and a right rear wheel 3RR provided at intervals in the left-right direction Y. In the present embodiment, the left front wheel 3FL and the left rear wheel 3RL are drive wheels that roll by transmitting the driving force for the automated guided vehicle 1 to travel, and the right front wheel 3FR and the right rear wheel 3RR are driven wheels that roll along with the rolling of the left front wheel 3FL and the left rear wheel 3RL. When the left front wheel 3FL, the right front wheel 3FR, the left rear wheel 3RL, and the right rear wheel 3RR (hereinafter collectively referred to as "four wheels") face the front-rear direction X, the automated guided vehicle 1 is in the normal traveling mode, and when the four wheels face the left-right direction Y, the automated guided vehicle 1 is in the lateral traveling mode. The four wheels are each configured to be rotatable about an axis A orthogonal to the front-rear direction X and the left-right direction Y.

[0017] The guiding sensors 4F and 4R are provided at intervals in the longitudinal direction X. When the driverless transport vehicle 1 travels in the normal driving mode, the guiding sensors 4F and 4R detect a guiding line LX provided on the road surface so as to extend in the longitudinal direction X, and output the detection result to a control device 8 (see FIG. 2) described later.

[0018] The guiding sensors 5L and 5R are provided at intervals in the lateral direction Y. When the driverless transport vehicle 1 travels in the crab mode, the guiding sensors 5L and 5R detect a guiding line LY provided on the road surface so as to extend in the lateral direction Y, and output the detection result to a control device 8 (see FIG. 2) described later.

[0019] Also, as shown in FIG. 2, the driverless transport vehicle 1 includes drive units 6FL and 6RL (hereinafter collectively referred to as "drive unit 6"), steering devices 7FL, 7FR, 7RL, and 7RR (hereinafter collectively referred to as "steering device 7"), and a control device 8.

[0020] The drive unit 6 is composed of a traveling motor with a brake. The drive unit 6 functions as a driving device for driving drive wheels by operating the traveling motor, and also functions as a braking device for restricting the rolling of the drive wheels by operating the brake of the traveling motor. The drive unit 6FL is a driving device and a braking device for the left front wheel 3FL, and the drive unit 6RL is a driving device and a braking device for the left rear wheel 3RL.

[0021] The steering device 7 is composed of a steering motor with a potentiometer. The steering device 7 changes the direction (steering angle) of the wheels by rotating the wheels around the axis A (see FIG. 1). The steering device 7FL changes the direction of the left front wheel 3FL, the steering device 7FR changes the direction of the right front wheel 3FR, the steering device 7RL changes the direction of the left rear wheel 3RL, and the steering device 7RR changes the direction of the right rear wheel 3RR.

[0022] The control device 8 is composed of a programmable logic controller and a motor driver. When the automated guided vehicle 1 is in the normal running mode, the control device 8 controls the drive unit 6 and the steering device 7 so as to run along the guidance line LX detected by the guidance sensors 4F and 4R. When the automated guided vehicle 1 is in the lateral running mode, the control device 8 controls the drive unit 6 and the steering device 7 so as to run along the guidance line LY detected by the guidance sensors 5L and 5R.

[0023] Also, the control device 8 performs a running mode switching process when switching from the normal running mode to the lateral running mode and when switching from the lateral running mode to the normal running mode by controlling the drive unit 6 and the steering device 7. In the running mode switching process, the control device 8 designates one set of wheels among the four wheels, which are a plurality of wheels, as the primary steering wheels and the other set of wheels as the secondary steering wheels, and controls the steering device 7 so as to change the direction of the secondary steering wheels after changing the direction of the primary steering wheels. In the present embodiment, the control device 8 designates the left front wheel 3FL and the right rear wheel 3RR as the primary steering wheels, and the right front wheel 3FR and the left rear wheel 3RL as the secondary steering wheels, and controls the steering devices 7FL and 7RR, and then controls the steering devices 7FR and 7RL.

[0024] Furthermore, the control device 8 controls the drive unit 6 so as to limit the rolling of at least one wheel included in the secondary steering wheels when changing the direction of the primary steering wheels, and to limit the rolling of at least one wheel included in the primary steering wheels when changing the direction of the secondary steering wheels. In the present embodiment, the control device 8 controls the drive unit 6RL so as to limit the rolling of the left rear wheel 3RL when changing the directions of the left front wheel 3FL and the right rear wheel 3RR, and controls the drive unit 6FL so as to limit the rolling of the left front wheel 3FL when changing the directions of the right front wheel 3FR and the left rear wheel 3RL.

[0025] Referring to FIG. 3, the flow of the running mode switching process for switching between the normal running mode and the lateral running mode will be described in detail. The running mode switching process is started when the automated guided vehicle 1 is in a stopped state.

[0026] First, the control device 8 releases the braking of the drive wheels included in the primary steering wheels (step S1). In the present embodiment, the control device 8 releases the braking of the left front wheel 3FL by releasing the brake of the drive unit 6FL.

[0027] Next, the control device 8 changes the direction of the primary steering wheels so that the steering angle of the primary steering wheels changes by 90 degrees (step S2). In the present embodiment, the control device 8 changes the directions of the left front wheel 3FL and the right rear wheel 3RR by operating the steering devices 7FL and 7RR so that the steering angles of the left front wheel 3FL and the right rear wheel 3RR change by 90 degrees.

[0028] Next, the control device 8 restricts the rolling of the drive wheels included in the primary steering wheels (step S3), and releases the braking of the drive wheels included in the secondary steering wheels (step S4). In the present embodiment, the control device 8 restricts the rolling of the left front wheel 3FL by operating the brake of the drive unit 6FL, and releases the braking of the left rear wheel 3RL by releasing the brake of the drive unit 6RL.

[0029] Next, the control device 8 changes the direction of the secondary steering wheels so that the steering angle of the secondary steering wheels changes by 90 degrees (step S5). In the present embodiment, the control device 8 changes the directions of the right front wheel 3FR and the left rear wheel 3RL by operating the steering devices 7FR and 7RL so that the steering angles of the right front wheel 3FR and the left rear wheel 3RL change by 90 degrees.

[0030] Then, the control device 8 restricts the rolling of the drive wheels included in the secondary steering wheels (step S6). In the present embodiment, the control device 8 restricts the rolling of the left rear wheel 3RL by operating the brake of the drive unit 6RL.

[0031] With reference to FIG. 4, the change in the directions of the front wheels 3F and the rear wheels 3R when switching from the normal traveling mode to the crab mode will be described. In FIG. 4, the wheels in the state where the rolling is restricted are illustrated by thick lines as compared with the wheels in the state where the rolling is not restricted.

[0032] As shown in FIG. 4(A), before switching from the normal running mode to the sideward running mode, the driving units 6FL and 6RL operate the brakes, so that the rolling of the left front wheel 3FL and the left rear wheel 3RL is restricted to stop the unmanned carrier vehicle 1. If the unmanned carrier vehicle 1 has stopped running, the running mode switching process may be started without restricting the rolling of the left front wheel 3FL and the left rear wheel 3RL.

[0033] Next, as shown in FIG. 4(B), the steering devices 7FL and 7RR change the directions of the left front wheel 3FL and the right rear wheel 3RR, so that the left front wheel 3FL and the right rear wheel 3RR face the left - right direction Y. At this time, by releasing the brake of the driving unit 6FL, the restriction on the rolling of the left front wheel 3FL is released, and by operating the brake of the driving unit 6RL, the rolling of the left rear wheel 3RL is restricted. Therefore, the displacement of the vehicle body 2 in the front - rear direction X is suppressed by the left rear wheel 3RL, and the displacement of the vehicle body 2 in the left - right direction Y is suppressed by the right front wheel 3FR and the left rear wheel 3RL.

[0034] Next, as shown in FIG. 4(C), the steering devices 7FR and 7RL change the directions of the right front wheel 3FR and the left rear wheel 3RL, so that the right front wheel 3FR and the left rear wheel 3RL also face the left - right direction Y. At this time, by releasing the brake of the driving unit 6RL, the restriction on the rolling of the left rear wheel 3RL is released, and by operating the brake of the driving unit 6FL, the rolling of the left front wheel 3FL is restricted. Therefore, the displacement of the vehicle body 2 in the front - rear direction X is suppressed by the left front wheel 3FL and the right rear wheel 3RR, and the displacement of the vehicle body 2 in the left - right direction Y is suppressed by the left front wheel 3FL.

[0035] Then, as shown in FIG. 4(D), after switching from the normal running mode to the sideward running mode, the driving units 6FL and 6RL operate the brakes, so that the rolling of the left front wheel 3FL and the left rear wheel 3RL is restricted until the unmanned carrier vehicle 1 starts running. After switching from the normal running mode to the sideward running mode, the unmanned carrier vehicle 1 may start running without restricting the rolling of the left front wheel 3FL and the left rear wheel 3RL.

[0036] The following effects can be obtained in this embodiment. (1) When switching between the normal driving mode and the crab mode, the control device 8 uses the left front wheel 3FL and the right rear wheel 3RR as the primary steering wheels, and the right front wheel 3FR and the left rear wheel 3RL as the secondary steering wheels, and controls the steering device 7 so as to change the direction of the secondary steering wheels after changing the direction of the primary steering wheels. Further, the control device 8 controls the drive unit 6 (braking device) so as to restrict the rolling of the left rear wheel 3RL included in the secondary steering wheels when changing the direction of the primary steering wheels, and restrict the rolling of the left front wheel 3FL included in the primary steering wheels when changing the direction of the secondary steering wheels. According to this configuration, when the direction of the primary steering wheels changes, the attitude change of the vehicle body 2 is suppressed because the secondary steering wheels including the left rear wheel 3RL whose rolling is restricted do not move. When the direction of the secondary steering wheels changes, the attitude change of the vehicle body 2 is suppressed because the primary steering wheels including the left front wheel 3FL whose rolling is restricted do not move. Therefore, the attitude change of the vehicle body 2 can be suppressed when switching between the normal driving mode and the crab mode.

[0037] (2) One set of the left front wheel 3FL and the right rear wheel 3RR is the primary steering wheels, and one set of the right front wheel 3FR and the left rear wheel 3RL is the secondary steering wheels. Therefore, by changing the directions of the pair of front wheels 3F and rear wheels 3R arranged at a distance at the same time, the attitude change of the vehicle body 2 can be further suppressed.

[0038] The present invention is not limited to the above embodiment, and the above configuration can also be changed. For example, it can be implemented by changing as follows, or can be implemented by combining the following changes.

[0039] · The right front wheel 3FR and the left rear wheel 3RL may be used as the primary steering wheels, and the left front wheel 3FL and the right rear wheel 3RR may be used as the secondary steering wheels. In this case, the control device 8 controls the drive unit 6 so as to restrict the rolling of the left front wheel 3FL included in the secondary steering wheels when changing the direction of the primary steering wheels, and restrict the rolling of the left rear wheel 3RL included in the primary steering wheels when changing the direction of the secondary steering wheels.

[0040] · By changing the configuration of the drive unit 6, the right front wheel 3FR and the right rear wheel 3RR may be used as drive wheels, and the left front wheel 3FL and the left rear wheel 3RL may be used as driven wheels. That is, the rolling of the right front wheel 3FR and the right rear wheel 3RR may be configured to be restricted by the braking device.

[0041] · By changing the configuration of the drive unit 6, either one of the front wheels 3F and the rear wheels 3R may be used as a drive wheel and the other as a driven wheel. That is, the rolling of the left front wheel 3FL and the right front wheel 3FR, or the rolling of the left rear wheel 3RL and the right rear wheel 3RR may be configured to be restricted by the braking device.

[0042] Referring to FIG. 5, in the configuration in which the rolling of the left front wheel 3FL and the right front wheel 3FR is restricted, the change in the directions of the front wheels 3F and the rear wheels 3R when switching from the normal traveling mode to the crab mode will be described.

[0043] As shown in FIG. 5(A), before switching from the normal traveling mode to the crab mode, the rolling of the left front wheel 3FL and the right front wheel 3FR is restricted so that the automated guided vehicle 1 stops traveling.

[0044] Next, as shown in FIG. 5(B), by changing the directions of the left front wheel 3FL and the right rear wheel 3RR by the steering devices 7FL, 7RR, the left front wheel 3FL and the right rear wheel 3RR face the left-right direction Y. At this time, the restriction on the rolling of the left front wheel 3FL is released, and the rolling of the right front wheel 3FR is restricted. For this reason, the displacement of the vehicle body 2 in the front-rear direction X is suppressed by the right front wheel 3FR, and the displacement of the vehicle body 2 in the left-right direction Y is suppressed by the right front wheel 3FR and the left rear wheel 3RL.

[0045] Next, as shown in FIG. 5(C), by changing the directions of the right front wheel 3FR and the left rear wheel 3RL by the steering devices 7FR, 7RL, the right front wheel 3FR and the left rear wheel 3RL also face the left-right direction Y. At this time, the restriction on the rolling of the right front wheel 3FR is released, and the rolling of the left front wheel 3FL is restricted. For this reason, the displacement of the vehicle body 2 in the front-rear direction X is suppressed by the left front wheel 3FL and the right rear wheel 3RR, and the displacement of the vehicle body 2 in the left-right direction Y is suppressed by the left front wheel 3FL.

[0046] And, as shown in FIG. 5(D), after switching from the normal running mode to the lateral running mode, the rolling of the left front wheel 3FL and the right front wheel 3FR is restricted until the AGV 1 starts running.

[0047] · By changing the configuration of the drive unit 6, one of the pair of the left front wheel 3FL and the right rear wheel 3RR and the pair of the right front wheel 3FR and the left rear wheel 3RL may be a drive wheel and the other may be a driven wheel. That is, the rolling of the left front wheel 3FL and the right rear wheel 3RR or the rolling of the right front wheel 3FR and the left rear wheel 3RL may be configured to be restricted by a braking device.

[0048] With reference to FIG. 6, in a configuration in which the left front wheel 3FL and the right rear wheel 3RR are drive wheels and the left front wheel 3FL and the left rear wheel 3RL are primary steering wheels, the change in the directions of the front wheels 3F and the rear wheels 3R when switching from the normal running mode to the lateral running mode will be described.

[0049] As shown in FIG. 6(A), before switching from the normal running mode to the lateral running mode, the rolling of the left front wheel 3FL and the right rear wheel 3RR is restricted so that the AGV 1 stops running.

[0050] Next, as shown in FIG. 6(B), by changing the directions of the left front wheel 3FL and the left rear wheel 3RL by the steering devices 7FL, 7RL, the left front wheel 3FL and the left rear wheel 3RL face the left-right direction Y. At this time, the restriction on the rolling of the left front wheel 3FL is released and the rolling of the right rear wheel 3RR is restricted. For this reason, the displacement of the vehicle body 2 in the front-rear direction X is suppressed by the right rear wheel 3RR, and the displacement of the vehicle body 2 in the left-right direction Y is suppressed by the right front wheel 3FR and the right rear wheel 3RR.

[0051] Next, as shown in FIG. 6(C), by changing the directions of the steering devices 7FR and 7RR of the right front wheel 3FR and the right rear wheel 3RR, the right front wheel 3FR and the right rear wheel 3RR also face the left-right direction Y. At this time, the rolling restriction of the right rear wheel 3RR is released, and the rolling of the left front wheel 3FL is restricted. For this reason, the displacement of the vehicle body 2 in the front-rear direction X is suppressed by the left front wheel 3FL and the left rear wheel 3RL, and the displacement of the vehicle body 2 in the left-right direction Y is suppressed by the left front wheel 3FL.

[0052] Then, as shown in FIG. 6(D), after switching from the normal traveling mode to the crab mode, the rolling of the left front wheel 3FL and the right rear wheel 3RR is restricted until the automated guided vehicle 1 starts to travel.

[0053] Furthermore, with reference to FIG. 7, in a configuration in which the left front wheel 3FL and the right rear wheel 3RR are driving wheels and the front wheel 3F is a primary steering wheel, the change in the directions of the front wheel 3F and the rear wheel 3R when switching from the normal traveling mode to the crab mode will be described.

[0054] As shown in FIG. 7(A), before switching from the normal traveling mode to the crab mode, the rolling of the left front wheel 3FL and the right rear wheel 3RR is restricted so that the automated guided vehicle 1 stops traveling.

[0055] Next, as shown in FIG. 7(B), by changing the directions of the steering devices 7FL and 7FR of the left front wheel 3FL and the right front wheel 3FR, the left front wheel 3FL and the right front wheel 3FR face the left-right direction Y. At this time, the rolling restriction of the left front wheel 3FL is released, and the rolling of the right rear wheel 3RR is restricted. For this reason, the displacement of the vehicle body 2 in the front-rear direction X is suppressed by the right rear wheel 3RR, and the displacement of the vehicle body 2 in the left-right direction Y is suppressed by the left rear wheel 3RL and the right rear wheel 3RR.

[0056] Next, as shown in FIG. 7(C), by changing the directions of the steering devices 7RL and 7RR, the left rear wheel 3RL and the right rear wheel 3RR also face the left - right direction Y. At this time, the rolling restriction of the right rear wheel 3RR is released, and the rolling of the left front wheel 3FL is restricted. Therefore, the displacement of the vehicle body 2 in the front - rear direction X is suppressed by the left front wheel 3FL and the right front wheel 3FR, and the displacement of the vehicle body 2 in the left - right direction Y is suppressed by the left front wheel 3FL.

[0057] Then, as shown in FIG. 7(D), after switching from the normal running mode to the crab - walking mode, the rolling of the left front wheel 3FL and the right rear wheel 3RR is restricted until the automated guided vehicle 1 starts running.

[0058] · The automated guided vehicle 1 may be provided with five or more wheels. Also, the braking device may restrict the rolling of three or more wheels, and the control device may control the steering device so as to restrict the rolling of two or more wheels included in the secondary steering wheels when changing the direction of the primary steering wheels, or to restrict the rolling of two or more wheels included in the primary steering wheels when changing the direction of the secondary steering wheels.

Explanation of Signs

[0059] 1 Automated guided vehicle 2 Vehicle body 3F Front wheel (wheel) 3R Rear wheel (wheel) 3FL Left front wheel 3FR Right front wheel 3RL Left rear wheel 3RR Right rear wheel 7 Drive unit (braking device) 8 Steering device 8 Control device X Front - rear direction Y Left - right direction

Claims

1. An automated guided vehicle capable of switching between a normal driving mode in which it can drive straight in the front-rear direction and a transverse driving mode in which it can drive straight in the left-right direction, comprising a plurality of wheels provided at intervals in the front-rear direction and the left-right direction, a braking device that restricts the rolling of at least two of the wheels, a steering device that changes the direction of the plurality of wheels, and a control device that controls the braking device and the steering device, wherein the control device uses one set of the plurality of wheels as primary steering wheels and another set of the wheels as secondary steering wheels, and when switching between the normal driving mode and the transverse driving mode, controls the steering device to change the direction of the secondary steering wheels after changing the direction of the primary steering wheels, and further controls the braking device to restrict the rolling of at least one of the wheels included in the secondary steering wheels when changing the direction of the primary steering wheels, and to restrict the rolling of at least one of the wheels included in the primary steering wheels when changing the direction of the secondary steering wheels characterizing the automated guided vehicle.

2. comprising front wheels and rear wheels provided at intervals in the front-rear direction as the wheels, wherein the front wheels are composed of a left front wheel and a right front wheel provided at intervals in the left-right direction, and the rear wheels are composed of a left rear wheel and a right rear wheel provided at intervals in the left-right direction, and one of a set of the left front wheel and the right rear wheel and a set of the right front wheel and the left rear wheel is a primary steering wheel and the other is a secondary steering wheel characterizing the automated guided vehicle according to Claim 1.

3. Among a set of the left front wheel and the left rear wheel, a set of the right front wheel and the right rear wheel, a set of the left front wheel and the right front wheel, and a set of the left rear wheel and the right rear wheel, the rolling of any one set is restricted by the braking device characterizing the automated guided vehicle according to Claim 2.

4. comprising front wheels and rear wheels provided at intervals in the front-rear direction as the wheels, wherein the front wheels are composed of a left front wheel and a right front wheel provided at intervals in the left-right direction, and the rear wheels are composed of a left rear wheel and a right rear wheel provided at intervals in the left-right direction, and one of a set of the left front wheel and the left rear wheel, a set of the right front wheel and the right rear wheel, a set of the left front wheel and the right front wheel, or a set of the left rear wheel and the right rear wheel is a primary steering wheel characterizing the automated guided vehicle according to Claim 1.

5. One set of the left front wheel and the right rear wheel, and one set of the right front wheel and the left rear wheel, wherein the rolling of one of them is restricted by the braking device The driverless transport vehicle according to claim 4, characterized in that

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