Transport vehicle

Abstract

To provide a technique capable of smoothly progressing a follow-up motion of a transport vehicle.SOLUTION: A transport vehicle is capable of autonomously executing a follow-up motion of following a follow-up target. The transport vehicle includes: a vehicle body; wheels that are supported by the vehicle body and are grounded on the ground; a motor that drives the wheels; an offset angle detection part that detects an offset angle of the follow-up target with respect to a forward moving direction of the transport vehicle; and a control part. The control part is configured to be capable of executing follow-up motion control processing of controlling the follow-up motion of the transport vehicle. In the follow-up motion control processing, when the offset angle is within a first angle range including zero degree, the control part adjusts a turning angle during the follow-up motion of the transport vehicle to a normal turning angle corresponding to the offset angle, and when the offset angle is within a second angle range adjacent to the first angle range, the control part adjusts the turning angle during the follow-up motion of the transport vehicle to a suppressed turning angle that is suppressed more than the normal turning angle corresponding to the offset angle.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a transport vehicle. [Background technology]

[0002] Patent Document 1 discloses a transport vehicle capable of autonomously performing a following operation to follow a target object. The transport vehicle includes a vehicle body, wheels supported on the vehicle body and in contact with the ground, a prime mover for driving the wheels, an offset angle detection unit for detecting the offset angle of the target object relative to the forward direction of the transport vehicle, and a control unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2023 / 065170 Summary of the Invention [Problem to be solved by the invention]

[0004] During a following operation by a transport vehicle, the transport vehicle may be made to turn in order to quickly follow the object to be followed. The turning operation here refers to the operation of moving the transport vehicle forward while rotating the forward direction of the transport vehicle counterclockwise or clockwise. However, when the transport vehicle is made to turn, the range through which the transport vehicle passes increases (for example, an inner wheel difference occurs), making the transport vehicle more likely to come into contact with an obstacle. If the transport vehicle comes into contact with an obstacle, the following operation of the transport vehicle may not proceed smoothly. This specification provides a technology that enables the following operation of the transport vehicle to proceed smoothly. [Means for solving the problem]

[0005] The transport vehicle disclosed in this specification is capable of autonomously performing a following operation to follow a target object. The transport vehicle includes a vehicle body, wheels supported on the vehicle body and in contact with the ground, a prime mover for driving the wheels, an offset angle detection unit for detecting an offset angle of the target object relative to the forward direction of the transport vehicle, and a control unit. The control unit is configured to execute a following operation control process for controlling the following operation of the transport vehicle. In the following operation control process, when the offset angle is within a first angle range including 0 degrees, the control unit adjusts the turning angle of the transport vehicle during the following operation to a normal turning angle corresponding to the offset angle, and when the offset angle is within a second angle range adjacent to the first angle range, the control unit adjusts the turning angle of the transport vehicle during the following operation to a suppressed turning angle that is suppressed more than the normal turning angle corresponding to the offset angle.

[0006] The larger the absolute value of the offset angle, the larger the turning angle required to turn the forward direction of the transport vehicle toward the target object, so it is possible to increase the turning angle of the transport vehicle. However, if the turning angle of the transport vehicle becomes excessively large, the range of movement of the transport vehicle may become excessively large. As a result, the transport vehicle may come into contact with an obstacle, preventing the smooth following operation of the transport vehicle. According to the above configuration, when the offset angle is within the second angle range (i.e., when the absolute value of the offset angle is relatively large), the turning angle of the transport vehicle is suppressed more than usual. This prevents the turning angle of the transport vehicle from becoming excessively large, thereby preventing the range of movement of the transport vehicle from becoming excessively large. This prevents the transport vehicle from coming into contact with an obstacle, allowing the smooth following operation of the transport vehicle.

[0007] Another transport vehicle disclosed herein is capable of autonomously performing a following operation to follow a target object. The transport vehicle includes a vehicle body, wheels supported on the vehicle body and in contact with the ground, a prime mover for driving the wheels, an offset angle detection unit for detecting an offset angle of the target object relative to the forward direction of the transport vehicle, and a control unit. When the offset angle is within an operating angle range including 0 degrees, the control unit operates the prime mover to cause the transport vehicle to perform the following operation, and when the offset angle is within a stop angle range adjacent to the operating angle range, the control unit stops the prime mover to stop the following operation by the transport vehicle.

[0008] The larger the absolute value of the offset angle, the larger the turning angle required to turn the forward direction of the transport vehicle toward the object to be followed, and therefore the transport vehicle will be forced to make a larger turn. However, if the transport vehicle is turned a larger turn, there is a risk that the transport vehicle will come into contact with an obstacle and the following operation of the transport vehicle will not proceed smoothly. According to the above configuration, when the offset angle is within the operating angle range (i.e., when the absolute value of the offset angle is relatively small), the following operation of the transport vehicle is performed. When the offset angle is within the stop angle range (i.e., when the absolute value of the offset angle is relatively large), the following operation of the transport vehicle is stopped. This makes it possible to prevent the transport vehicle from making a larger turn. As a result, the transport vehicle can be prevented from coming into contact with an obstacle, and the following operation of the transport vehicle can proceed smoothly.

[0009] The term "turning degree" as used herein is an index that indicates the speed of a turning motion of a vehicle. The term "turning degree" can be substituted with, for example, the curvature of the turning radius of the vehicle (turning curvature) or the angle of the steering wheels relative to the forward direction of the vehicle. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is an overall perspective view of a transporter 2 according to a first embodiment. [Figure 2] 1 is a block diagram showing the configuration of a transporter 2 according to a first embodiment. [Figure 3]1 is an overall perspective view of a beacon 82 according to a first embodiment. [Figure 4] 2 is a circuit diagram showing an electrical configuration of a beacon 82 according to the first embodiment. FIG. [Figure 5] 10 is a flowchart of a process executed by a microcomputer 102 of a beacon 82 when a main power supply of the beacon 82 according to the first embodiment is ON. [Figure 6] 10 is a flowchart of a process executed by a control unit 52 of the transporter 2 when the main power supply of the transporter 2 according to the first embodiment is ON. [Figure 7] 10 is a flowchart of a follow-up operation control process executed by a control unit 52 of the transporter 2 according to the first embodiment. [Figure 8] 1 is a diagram schematically illustrating a first angle range A1, a second angle range A2, and a third angle range A3 as viewed from the transporter 2 according to the first embodiment. FIG. [Figure 9] 10 is a graph showing an example of the relationship between the offset angle θo and the turning curvature K of the transporter 2 during a following operation in the transporter 2 according to the first embodiment. [Figure 10] 10 is a flowchart of a follow-up operation control process executed by a control unit 52 of a transporter 2 according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Representative, non-limiting embodiments of the present invention are described in detail below with reference to the drawings. This detailed description is intended simply to provide those skilled in the art with details for implementing preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Additionally, the additional features and inventions disclosed may be used separately or in conjunction with other features and inventions to provide further improved transport vehicles.

[0012] Furthermore, the combinations of features and steps disclosed in the following detailed description are not essential to practicing the invention in its broadest sense, but are described solely to specifically illustrate exemplary embodiments of the invention. Furthermore, the various features of the following exemplary embodiments and those described in the claims do not necessarily have to be combined in the exact embodiments described herein or in the exact order listed to provide additional and useful embodiments of the invention.

[0013] All features described in this specification and / or claims are intended to be disclosed individually and independently of one another as limitations to the specific features described in the original disclosure and claims, apart from the configuration of features described in the examples and / or claims. Furthermore, all numerical ranges and group or aggregate descriptions are intended to disclose intermediate configurations thereof as limitations to the specific features described in the original disclosure and claims.

[0014] In one or more embodiments, the turning angle may include a turning curvature of the transporter. In the following operation control process, the control unit may adjust the turning curvature of the transporter during the following operation to a normal turning curvature corresponding to the offset angle when the offset angle is within the first angle range, and adjust the turning curvature of the transporter during the following operation to a suppressed turning curvature that is reduced below the normal turning curvature corresponding to the offset angle when the offset angle is within the second angle range.

[0015] According to the above configuration, when the offset angle is within the second angle range (i.e., when the absolute value of the offset angle is relatively large), the turning curvature of the transport vehicle is reduced compared to normal. This prevents the turning curvature of the transport vehicle from becoming excessively large, thereby preventing the range through which the transport vehicle passes from becoming excessively large. This prevents the transport vehicle from coming into contact with an obstacle, allowing the transport vehicle to follow the obstacle smoothly.

[0016] In one or more embodiments, the transporter may be switchable between a follow mode in which the transporter is permitted to perform the follow operation and a manual mode in which the transporter is prohibited from performing the follow operation and moves based on a user's operation, and a minimum turning radius of the transporter in the follow mode may be greater than a minimum turning radius of the transporter in the manual mode.

[0017] As the turning radius of the transport vehicle decreases, the range over which the transport vehicle passes increases. Therefore, in the following mode, in which the user does not intervene, there is a possibility that the transport vehicle will come into contact with an obstacle if the turning radius of the transport vehicle decreases. On the other hand, in the manual mode, in which the user intervenes, it is considered that the transport vehicle is unlikely to come into contact with an obstacle even if the turning radius of the transport vehicle decreases to a certain extent. In fact, if the turning radius of the transport vehicle cannot be reduced in the manual mode, the operability of the transport vehicle may be reduced. According to the above configuration, the minimum turning radius of the transport vehicle in the following mode is larger than the minimum turning radius of the transport vehicle in the manual mode. As a result, the turning radius of the transport vehicle is prevented from being reduced in the following mode, while the turning radius is allowed to be reduced in the manual mode. This makes it possible to prevent the transport vehicle from coming into contact with an obstacle in the following mode without impairing the operability of the transport vehicle in the manual mode.

[0018] In one or more embodiments, in the following operation control process, the control unit may stop the prime mover and stop the following operation by the transport vehicle when the offset angle is within a third angle range excluding the first angle range and the second angle range.

[0019] The larger the absolute value of the offset angle, the larger the turning angle required to turn the forward direction of the transport vehicle toward the target object, resulting in a larger turning angle for the transport vehicle. However, if the transport vehicle is turned too far, there is a risk that the transport vehicle may come into contact with an obstacle, preventing the smooth following operation of the transport vehicle. According to the above configuration, when the offset angle is within the third angle range (i.e., when the absolute value of the offset angle is relatively large), the following operation of the transport vehicle is stopped. This makes it possible to prevent the transport vehicle from making large turns. As a result, the transport vehicle can be prevented from coming into contact with an obstacle, allowing the smooth following operation of the transport vehicle.

[0020] (Example 1: Transport System 1) As shown in FIGS. 1 to 4, the transportation system 1 includes a transportation vehicle 2 and a beacon 82 .

[0021] (Configuration of transport vehicle 2) The transporter 2 shown in FIG. 1 includes a vehicle body 4, a loading platform 6, a handlebar 8, a right front wheel 10, a left front wheel 12, a right rear wheel 14, and a left rear wheel 16. The loading platform 6, the handlebar 8, the right front wheel 10, the left front wheel 12, the right rear wheel 14, and the left rear wheel 16 are all supported by the vehicle body 4. The transporter 2 transports cargo loaded on the loading platform 6. The transporter 2 includes a communication module 18 (see FIG. 2) mounted on the vehicle body 4. The transporter 2 can operate in either a manual mode, a following mode, or a parking mode. In the manual mode, the transporter 2 moves forward or backward in response to operation by a user standing behind the vehicle body 4 and holding the handlebar 8 with both hands. In the following mode, the transporter 2 performs a following operation, in which the transporter 2 moves by tracking a beacon 82 (see FIG. 3) carried by a user standing in front of the vehicle body 4. In this case, the transporter 2 communicates with the beacon 82 via the communication module 18. In the parking mode, the transporter 2 continues to stop in place without accepting commands from the handle 8 or the beacon 82.

[0022] The transport vehicle 2 has a battery mounting section 20 provided on the vehicle body 4. A battery pack 22 (see FIG. 2) can be attached and detached to the battery mounting section 20. The battery pack 22 has secondary battery cells (not shown), such as lithium-ion battery cells, and can be recharged using a charger (not shown). The transport vehicle 2 operates using power supplied from the battery pack 22 attached to the battery mounting section 20.

[0023] 2, the transporter 2 includes a right front wheel motor 24 that drives the right front wheel 10, a left front wheel motor 26 that drives the left front wheel 12, a right rear wheel motor 28 that drives the right rear wheel 14, and a left rear wheel motor 30 that drives the left rear wheel 16. The right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 are, for example, brushless motors. The right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 are supported by the vehicle body 4.

[0024] As shown in FIG. 1, the handle 8 is rotatable around a rotation axis that extends in the vertical direction relative to the vehicle body 4. A user can rotate the handle 8 while holding the handle 8 with both hands. As shown in FIG. 2, the transporter 2 is equipped with a handle angle sensor 32 that detects the rotation angle of the handle 8 as a handle angle, a steering mechanism 34 that steers the right front wheel 10 and the left front wheel 12 as steered wheels, and a steering motor 36 that drives the steering mechanism 34. The steering motor 36 is, for example, a brushless motor. The handle angle sensor 32, the steering mechanism 34, and the steering motor 36 are supported by the vehicle body 4.

[0025] As shown in FIG. 1, the handle 8 is provided with switch boxes 38a and 38b. As shown in FIG. 2, the switch boxes 38a and 38b are provided with a main power switch 40, a mode selector switch 42, a trigger switch 44, a traveling direction selector switch 46, and a speed selector switch 48. The main power switch 40 can switch the main power of the transporter 2 on and off. The mode selector switch 42 can switch the operation mode of the transporter 2 between manual mode, following mode, and parking mode. In manual mode, the trigger switch 44 can switch the traveling of the transporter 2 on and off and adjust the traveling speed of the transporter 2. In manual mode, the traveling direction selector switch 46 can switch the traveling direction of the transporter 2 between forward and reverse. In manual mode, the speed selector switch 48 can switch the traveling speed of the transporter 2 between a low speed state and a high speed state. The user can operate the main power switch 40, the mode selector switch 42, the trigger switch 44, the travel direction selector switch 46, and the speed selector switch 48 while holding the handle 8 with both hands.

[0026] The transport vehicle 2 includes a control power circuit 50 and a control unit 52. When the main power switch 40 is turned ON, the control power circuit 50 allows power to be supplied from the battery pack 22 to each component of the transport vehicle 2 (e.g., the control unit 52, the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, the left rear wheel motor 30, the steering motor 36, etc.), and when the main power switch 40 is turned OFF, the control power circuit 50 prohibits power from being supplied from the battery pack 22 to each component of the transport vehicle 2. The control power circuit 50 adjusts the power supplied from the battery pack 22 to a voltage suitable for each component of the transport vehicle 2 and outputs the adjusted voltage to each component of the transport vehicle 2. The control unit 52 includes a CPU, ROM, RAM, etc. The control unit 52 controls the operation of the transport vehicle 2 by having the CPU execute processing based on information stored in the ROM and RAM. The control unit 52 controls the operation of the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, the left rear wheel motor 30, and the steering motor 36 via motor drivers 54, 56, 58, 60, and 62. Brake circuits 64, 66, 68, and 70 are connected to the motor drivers 54, 56, 58, and 60, respectively, for the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30. The control unit 52 can apply a large braking force to the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 by passing a large current through the brake circuits 64, 66, 68, and 70 while the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 are rotating. The control power supply circuit 50 , the control unit 52 , the motor drivers 54 , 56 , 58 , 60 , 62 , and the brake circuits 64 , 66 , 68 , 70 are supported by the vehicle body 4 .

[0027] (Beacon 82 configuration) The beacon 82 shown in FIG. 3 is a communication terminal configured to be able to communicate with the transporter 2. The beacon 82 includes a housing 84, a main power switch 86, an initialization switch 88, a pairing switch 90, a tracking start switch 92, and a tracking stop switch 94. The housing 84 has a substantially rectangular parallelepiped shape. A clip portion 96 is provided on the rear surface of the housing 84. The beacon 82 can be attached to the user's body (e.g., a waist belt) via the clip portion 96. A ring portion 98 is provided on the upper portion of the housing 84. The beacon 82 can be held by a holder (e.g., a carabiner) attached to the user's body via the ring portion 98. The main power switch 86 is provided on the front surface of the housing 84, offset upward and to the left from the center. The initialization switch 88 is provided on the front surface of the housing 84, offset downward and to the right from the center. The pairing switch 90 is provided on the right surface of the housing 84. The follow start switch 92 and the follow stop switch 94 are provided in the center of the front surface of the housing 84. The follow start switch 92 is located above the follow stop switch 94. The surface of the follow start switch 92 is provided with a protrusion 100, which gives the switch an uneven shape. For example, the protrusion 100 is made up of multiple ridges extending in the left-right direction. On the other hand, the surface of the follow stop switch 94 has a flat shape. Therefore, the user can distinguish between the follow start switch 92 and the follow stop switch 94 by checking whether the protrusion 100 is present. Note that the front-rear direction, left-right direction, and up-down direction shown in FIG. 3 are different from the front-rear direction, left-right direction, and up-down direction (see FIG. 1) relative to the transporter 2.

[0028] 4, the beacon 82 includes a microcomputer 102, a power supply IC 104, a charging IC 106, a battery protection IC 108, a battery interface 110, and a USB port 112. As will be described in detail later, the beacon 82 operates using power supplied from a battery 128 or the USB port 112.

[0029] A first conductive path 114, a second conductive path 116, and a third conductive path 118 are provided between the microcontroller 102, the battery interface 110, and the USB port 112. One end of the first conductive path 114 is connected to the battery interface 110. One end of the second conductive path 116 is connected to the microcontroller 102. One end of the third conductive path 118 is connected to the USB port 112. The other end of the first conductive path 114, the other end of the second conductive path 116, and the other end of the third conductive path 118 are connected to one another at a connection point 120.

[0030] The first conductive path 114 is provided with a fuse 122, a battery protection switch circuit 124, and a first charging switch circuit 126 of the charging IC 106 in this order from the battery interface 110 toward the connection point 120.

[0031] A battery 128 is attached to the battery interface 110. The battery 128 is, for example, a coin-type rechargeable secondary battery (for example, a lithium-ion battery).

[0032] The battery protection switch circuit 124 of this embodiment is an N-channel MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor), with the drain-to-source direction being the direction from the battery interface 110 to the connection point 120. Therefore, when the battery protection switch circuit 124 is ON, it allows current to flow from the battery interface 110 to the connection point 120, and when it is OFF, it prohibits current from flowing from the battery interface 110 to the connection point 120. A parasitic diode is also formed in the battery protection switch circuit 124. This parasitic diode allows current to flow from the source to the drain of the MOSFET. Therefore, the battery protection switch circuit 124 allows current to flow from the connection point 120 to the battery interface 110, regardless of whether the battery protection switch circuit 124 is ON or OFF.

[0033] The first charging switch circuit 126 in this embodiment is a P-channel MOSFET, and the direction from source to drain is the direction from the connection point 120 to the battery interface 110. Therefore, when the first charging switch circuit 126 is ON, it allows current to flow from the connection point 120 to the battery interface 110, and when it is OFF, it prohibits current from flowing from the connection point 120 to the battery interface 110. In addition, a parasitic diode is formed in the first charging switch circuit 126. This parasitic diode allows current to flow from the drain to the source of the MOSFET. Therefore, the first charging switch circuit 126 allows current to flow from the battery interface 110 to the connection point 120 regardless of whether the first charging switch circuit 126 is ON or OFF.

[0034] The battery protection IC 108 is configured to detect whether an abnormality has occurred in the battery 128, and switch the battery protection switch circuit 124 and / or the first charging switch circuit 126 ON / OFF based on the detection result. For example, if the temperature of the battery 128 is excessively high (e.g., a temperature of 60 degrees or higher), the battery protection IC 108 switches the battery protection switch circuit 124 and the first charging switch circuit 126 OFF. This prohibits charging to and discharging from the battery 128. Alternatively, if the battery 128 is in an over-discharge state, the battery protection IC 108 switches the battery protection switch circuit 124 OFF. This prohibits discharging from the battery 128. Alternatively, if the battery 128 is in an over-charge state, the battery protection IC 108 switches the first charging switch circuit 126 OFF. This prohibits charging to the battery 128. Furthermore, the battery protection IC 108 can also switch the first charging switch circuit 126 ON / OFF based on a signal output from the microcomputer 102, as will be described in detail later.

[0035] In the second conductive path 116, a regulator 130 of the power supply IC 104 and a power switch circuit 132 of the power supply IC 104 are provided in this order from the microcomputer 102 toward the connection point 120.

[0036] The microcomputer 102 is composed of a CPU, ROM, RAM, etc. The microcomputer 102 controls the operation of the beacon 82 by having the CPU execute processing based on information stored in the ROM and RAM. The microcomputer 102 also includes a communication module 134 for communicating with the transport vehicle 2. The communication module 134 is configured to execute pairing with the communication module 18 (see FIG. 2) of the transport vehicle 2 when the pairing switch 90 is operated. By pairing the communication modules 18 and 134 in advance, they can automatically attempt to establish communication with the pairing partner when the power is turned on. The communication modules 18 and 134 each comply with the UWB (Ultra Wide Band) standard. Therefore, communication conforming to the UWB standard (UWB communication) can be performed between the transport vehicle 2 and the beacon 82.

[0037] When power is supplied from battery 128 or USB port 112, regulator 130 adjusts the supplied power to a predetermined control voltage (e.g., 3 V) and outputs it to microcomputer 102. By outputting the power adjusted to the control voltage to microcomputer 102, microcomputer 102 becomes operable.

[0038] The power switch circuit 132 of this embodiment is a P-channel MOSFET, and the direction from the source to the drain is the direction from the connection point 120 to the microcomputer 102. Therefore, when the power switch circuit 132 is ON, it allows current to flow from the connection point 120 to the microcomputer 102, and when it is OFF, it prohibits current from flowing from the connection point 120 to the microcomputer 102. Furthermore, a parasitic diode is formed in the power switch circuit 132. This parasitic diode allows current to flow from the drain to the source of the MOSFET. Therefore, the power switch circuit 132 allows current to flow from the microcomputer 102 to the connection point 120 regardless of whether the power switch circuit 132 is ON or OFF.

[0039] The third conductive path 118 is provided with a fuse 136 and a second charging switch circuit 138 of the charging IC 106 in this order from the USB port 112 toward the connection point 120 .

[0040] The second charging switch circuit 138 of this embodiment is an N-channel MOSFET, and the direction from drain to source is the direction from the USB port 112 to the connection point 120. Therefore, when the second charging switch circuit 138 is ON, it allows current to flow from the USB port 112 to the connection point 120, and when it is OFF, it prohibits current from flowing from the USB port 112 to the connection point 120. Furthermore, a parasitic diode is formed in the second charging switch circuit 138. This parasitic diode allows current to flow from the source to the drain of the MOSFET. Therefore, the second charging switch circuit 138 allows current to flow from the connection point 120 to the USB port 112 regardless of whether the second charging switch circuit 138 is ON or OFF.

[0041] Although not shown, the USB port 112 is provided on the outer surface of the housing 84 (see FIG. 3 ). A USB cable (not shown) can be connected to the USB port 112. When a USB cable connected to an external power source (e.g., a commercial power source) is connected to the USB port 112, power is supplied from the external power source to the beacon 82 via the USB cable and the USB port 112. In this case, the beacon 82 can operate using the power supplied from the USB port 112. In this embodiment, the state of the beacon 82 operating using the power supplied from the USB port 112 is referred to as an “external power operating state.” When the beacon 82 is in the external power operating state, voltages are applied to the gates of the second charging switch circuit 138 and the power switch circuit 132 by the power supplied from the external power source, and the second charging switch circuit 138 and the power switch circuit 132 are switched ON. In this case, power is allowed to be supplied from the USB port 112 to the microcomputer 102 via the third conductive path 118 and the second conductive path 116, and power from the external power source is supplied to the microcomputer 102. This starts up the microcomputer 102, and each part of the beacon 82 (for example, the battery protection IC 108) becomes operable.

[0042] When the beacon 82 is in an external power supply operating state, the microcomputer 102 switches the first charging switch circuit 126 ON / OFF depending on the remaining charge of the battery 128 (i.e., the voltage of the battery 128). For example, when the remaining charge of the battery 128 is low, the microcomputer 102 switches the first charging switch circuit 126 ON. This turns on both the first charging switch circuit 126 and the second charging switch circuit 138, allowing power to be supplied from the USB port 112 to the battery 128 via the third conductive path 118 and the first conductive path 114. As a result, power from the external power source is supplied to the battery 128, charging the battery 128. Then, when the remaining charge of the battery 128 recovers to a predetermined level, the microcomputer 102 switches the first charging switch circuit 126 OFF. This prohibits power from being supplied to the battery 128 via the third conductive path 118 and the first conductive path 114 from the USB port 112, thereby terminating charging of the battery 128. Furthermore, when the beacon 82 is in an external power supply operation state, the microcomputer 102 switches the power supply of the communication module 134 ON / OFF in response to operation of the main power switch 86. In this case, the power switch circuit 132 remains ON, and power from the external power supply continues to be supplied to the microcomputer 102. In other words, the "main power supply" of the beacon 82 here refers to the power supplied to the communication module 134. Furthermore, when the beacon 82 is in an external power supply operation state, the microcomputer 102 outputs a discharge permission signal to the battery protection IC 108. When the discharge permission signal is output from the microcomputer 102, the battery protection IC 108 switches the battery protection switch circuit 124 ON. This allows discharge from the battery 128. If the USB cable is removed from the USB port 112 with the battery protection switch circuit 124 ON and the power supply from the external power supply to the beacon 82 is interrupted, the beacon 82 operates using power supplied from the battery 128. In this embodiment, the state of the beacon 82 at this time is called the "internal power operating state."

[0043] When the beacon 82 is in an internal power supply operating state, the power switch circuit 132 is switched ON / OFF in response to operation of the main power switch 86. This switches between allowing and prohibiting power supply from the battery 128 to the microcomputer 102, and accordingly switches between operating and stopping the microcomputer 102. Furthermore, when the beacon 82 is in an internal power supply operating state, the microcomputer 102 outputs a discharge prohibition signal to the battery protection IC 108 in response to operation of the initialization switch 88. When the discharge prohibition signal is output from the microcomputer 102, the battery protection IC 108 switches the battery protection switch circuit 124 OFF. By turning the battery protection switch circuit 124 OFF, discharge from the battery 128 is prohibited, and accordingly operation of each part of the beacon 82 (such as the microcomputer 102) is stopped. In this embodiment, the state of the beacon 82 at this time is referred to as a "power-off state." After the beacon 82 is in a power-off state, in order to switch the battery protection switch circuit 124 ON and allow the battery 128 to discharge, it is necessary to connect a USB cable to the USB port 112 and start the microcomputer 102 using power supplied from an external power source.

[0044] (Example of using the initialization switch 88) After the beacon 82 is manufactured, it may be stored in a warehouse as inventory for a long period of time (for example, one year or more) before it is delivered to a user. Furthermore, even after the beacon 82 is delivered to a user, the user may not use the beacon 82 for a long period of time. During these periods, the beacon 82 may be left unused without charging the battery 128. In this case, the battery 128 may naturally discharge, resulting in the battery 128 becoming over-discharged. In this regard, the beacon 82 of this embodiment can suppress the natural discharge of the battery 128 by operating the initialization switch 88 to turn off the battery protection switch circuit 124. This prevents the battery 128 from becoming over-discharged, even if the beacon 82 is left unused for a long period of time without charging the battery 128.

[0045] (Processing when the main power of Beacon 82 is turned on: Figure 5) When the main power supply of the beacon 82 (that is, the power supply of the communication module 134) is ON, the microcomputer 102 executes the process shown in FIG.

[0046] In S2, the microcomputer 102 switches the beacon following flag to OFF. The beacon following flag here is information stored in the microcomputer 102, and takes on either an ON or OFF value. After S2, the process proceeds to S4.

[0047] In S4, the microcomputer 102 transmits a beacon following flag to the transport vehicle 2. After S4, the process proceeds to S6.

[0048] In S6, the microcomputer 102 determines whether or not response information from the vehicle 2 is received within a first predetermined time (e.g., 50 milliseconds) after S6 is started. When the vehicle 2 receives a beacon following flag transmitted from the beacon 82, the microcomputer 102 transmits response information to the beacon 82 in response to the beacon following flag (see S40 in FIG. 6, described later). The response information includes mode information indicating the operation mode of the vehicle 2 and a vehicle following flag. The vehicle following flag here is information stored in the control unit 52 (see FIG. 2) of the vehicle 2 and takes on either an ON or OFF value. The vehicle following flag can also be considered information indicating whether or not the vehicle 2 is performing a following operation. If no response information is received even after the first predetermined time has elapsed since S6 was started (NO), the process proceeds to S8.

[0049] In S8, the microcomputer 102 determines that radio waves have been blocked between the transport vehicle 2 and the beacon 82, and that this has prevented proper communication between the transport vehicle 2 and the beacon 82. After S8, the process returns to S4.

[0050] If response information is received within a first predetermined time period after S6 is started (YES in S6), the process proceeds to S10. In S10, the microcomputer 102 updates the beacon following flag using the vehicle following flag included in the response information received in S6. Specifically, if the vehicle following flag received in S6 indicates ON, the microcomputer 102 switches the beacon following flag to ON, and if the vehicle following flag received in S6 indicates OFF, the microcomputer 102 switches the beacon following flag to OFF. After S10, the process proceeds to S12.

[0051] In S12, the microcomputer 102 determines whether or not the follow mode is selected in the vehicle 2 based on the mode information included in the response information received in S6. If the follow mode is not selected in the vehicle 2 (NO), the process returns to S2. If the follow mode is selected in the vehicle 2 (YES), the process proceeds to S14.

[0052] In S14, the microcomputer 102 determines whether the follow-up start switch 92 (see FIG. 3) has been operated. If the follow-up start switch 92 has been operated (YES), the process proceeds to S16.

[0053] In S16, the microcomputer 102 switches the beacon following flag to ON.

[0054] If the follow-up start switch 92 has not been operated in S14 (NO), or after S16, the process proceeds to S18. In S18, the microcomputer 102 determines whether the follow-up stop switch 94 (see FIG. 3) has been operated. If the follow-up stop switch 94 has been operated (YES), the process proceeds to S20.

[0055] In S20, the microcomputer 102 switches the beacon following flag to OFF.

[0056] In S22, the microcomputer 102 transmits a beacon following flag to the transport vehicle 2. After S22, the process proceeds to S24.

[0057] In S24, the microcomputer 102 determines whether or not response information from the vehicle 2 is received within a first predetermined time period after S24 is started. As described above, the response information includes mode information indicating the operation mode of the vehicle 2 and a vehicle following flag. If no response information is received even after the first predetermined time period has elapsed since S24 was started (NO), the process proceeds to S8. If response information is received within the first predetermined time period after S24 was started (YES), the process returns to S12.

[0058] (Processing when the main power of transport vehicle 2 is turned on: Figure 6) When the main power supply of the transport vehicle 2 is ON, the control unit 52 (see FIG. 2) of the transport vehicle 2 executes the process shown in FIG.

[0059] In S32, the control unit 52 switches the vehicle following flag to OFF. As described above, the vehicle following flag is information stored in the control unit 52 and takes on either an ON or OFF value. After S32, the process proceeds to S34.

[0060] In S34, if the follow-up operation control process (see FIG. 7) is being executed, the control unit 52 ends the follow-up operation control process. The follow-up operation control process is a process for causing the guided vehicle 2 to execute a follow-up operation, as will be described in detail later. When the follow-up operation control process ends and is no longer executed, the guided vehicle 2 is no longer able to execute a follow-up operation. That is, in S34, the follow-up operation by the guided vehicle 2 is stopped. After S34, the process proceeds to S36.

[0061] In S36, the control unit 52 determines whether or not a beacon following flag (see S4 and S22 of the process shown in FIG. 5) transmitted from the beacon 82 has been received within a second predetermined time (e.g., 5 seconds) since S36 started. If a beacon following flag has not been received even after the second predetermined time has elapsed since S36 started (NO), the process proceeds to S38.

[0062] In S38, the control unit 52 determines that communication has been interrupted between the transporter 2 and the beacon 82. After S38, the process returns to S32.

[0063] If the beacon following flag is received within the second predetermined time period after S36 is started (YES in S36), the process proceeds to S40. In S40, response information is transmitted to the beacon 82. As described above, the response information includes mode information indicating the operation mode of the vehicle 2 and the vehicle following flag. After S40, the process proceeds to S42.

[0064] In S42, it is determined whether or not the follow mode is selected in the transporter 2. If the follow mode is not selected in the transporter 2 (NO), the process returns to S32. If the follow mode is selected in the transporter 2 (YES), the process proceeds to S44.

[0065] In S44, the control unit 52 determines whether the beacon following flag received in S36 is ON. If the beacon following flag received in S36 is ON (YES), the process proceeds to S46.

[0066] In S46, the control unit 52 switches the vehicle following flag to ON. After S46, the process proceeds to S48.

[0067] In S48, the control unit 52 starts the follow-up operation control process (see FIG. 7) if it is not currently being executed. As will be described in detail later, the execution of the follow-up operation control process enables the transport vehicle 2 to execute a follow-up operation. After S48, the process returns to S36.

[0068] If the beacon following flag received in S36 is OFF (NO in S44), the process proceeds to S50. In S50, the control unit 52 switches the vehicle following flag to OFF. After S50, the process proceeds to S52.

[0069] In S52, if the control unit 52 is executing the follow-up operation control process (see FIG. 7), it ends the follow-up operation control process. As will be described in detail later, once the follow-up operation control process is finished and is no longer being executed, the guided vehicle 2 will no longer be able to perform the follow-up operation. That is, in S52, the follow-up operation by the guided vehicle 2 is stopped. After S52, the process returns to S36.

[0070] (Regarding the instruction to start following / stop following from beacon 82 to transport vehicle 2) According to the process in Fig. 6, when a beacon following flag indicating ON is transmitted from the beacon 82 to the vehicle 2, the vehicle 2 starts following operation. On the other hand, when a beacon following flag indicating OFF is transmitted from the beacon 82 to the vehicle 2, the vehicle 2 stops following operation. For this reason, in this embodiment, a beacon following flag indicating ON is also referred to as a following start instruction from the beacon 82 to the vehicle 2. Furthermore, a beacon following flag indicating OFF is also referred to as a following stop instruction from the beacon 82 to the vehicle 2.

[0071] 5, immediately after the beacon 82 is powered on, a beacon following flag indicating OFF (following stop instruction) is transmitted to the transport vehicle 2 regardless of the operation on the beacon 82 (see S2 and S4 in FIG. 5). Therefore, after the beacon 82 is powered on, the beacon following flag indicating ON (following start instruction) is transmitted to the transport vehicle 2 only when the following start switch 92 (see FIG. 3) is operated. This makes it possible to prevent the transport vehicle 2 from starting the following operation at a timing unintended by the user.

[0072] 5, while communication between the transporter 2 and the beacon 82 is established and the transporter 2 is in the following mode (while the processes from S12 to S24 are repeatedly executed), an operation of the following start switch 92 (see FIG. 3) and an operation of the following stop switch 94 (see FIG. 3) are accepted. For this reason, in this embodiment, the period during which communication between the transporter 2 and the beacon 82 is established and the transporter 2 is in the following mode is also referred to as the "start operation acceptance period" and the "stop operation acceptance period." During the start operation acceptance period (stop operation acceptance period), once the following start switch 92 (following stop switch 94) is operated, the beacon 82 continues to transmit a following start instruction (following stop instruction) to the transporter 2 until the next time the following stop switch 94 (following start switch 92) is operated. This makes it possible to prevent a situation in which the following operation by the transport vehicle 2 never starts (stops) even though the user operates the following start switch 92 (following stop switch 94).

[0073] (Follow-up operation control process: Figure 7) The follow-up operation control process is a process for controlling the follow-up operation of the vehicle 2. The follow-up operation control process is executed in the process shown in FIG. 6 described above. Specifically, the follow-up operation control process is started when the vehicle 2 receives a beacon follow-up flag (follow-up start instruction) indicating ON from the beacon 82 (see S44-S48 in FIG. 6). The follow-up operation control process ends when the vehicle 2 receives a beacon follow-up flag (follow-up stop instruction) indicating OFF from the beacon 82, or when communication between the vehicle 2 and the beacon 82 is interrupted (see S44, S50, S52, S38, S32, and S34 in FIG. 6).

[0074] In S72 shown in Fig. 7, the control unit 52 determines the distance d to the beacon 82 and the offset angle θo of the beacon 82 using a positioning technique based on UWB communication, such as ToA (Time of Arrival) or AoA (Angle of Arrival). As shown in Fig. 8, the offset angle θo here is an offset angle with respect to the forward direction FD of the vehicle 2. In this embodiment, the clockwise direction when viewing the vehicle 2 from above is defined as the positive direction of the offset angle θo, and the counterclockwise direction is defined as the negative direction of the offset angle θo. After S72, the process proceeds to S74.

[0075] In S74 shown in Fig. 7, the control unit 52 determines whether the offset angle θo identified in S72 is within a predetermined first angle range A1. As shown in Fig. 8, the first angle range A1 is an angle range defined as -θ1≦θo≦θ1. The first boundary angle θ1 that defines the boundary of the first angle range A1 is, for example, within a range of 5 to 15 degrees, and is 10 degrees in this embodiment. If the offset angle θo is within the first angle range A1 (YES), the process proceeds to S76.

[0076] In S76 shown in Fig. 7, the control unit 52 determines the target angular velocity ω to be applied to the transporter 2 based on the offset angle θo determined in S72. As shown in Fig. 8, the target angular velocity ω here is an angular velocity around an axis extending in the vertical direction. In this embodiment, Equation (1) for deriving the target angular velocity ω from the offset angle θo is defined as follows: ω=ωk*θo (1) In addition, ωk in the equation (1) is a predetermined coefficient.

[0077] If the offset angle θo is not within the first angle range A1 in S74 shown in FIG. 7 (NO), the process proceeds to S78. In S78, the control unit 52 determines whether the offset angle θo identified in S72 is within a predetermined second angle range A2. As shown in FIG. 8, the second angle range A2 is adjacent to the first angle range A1 and is an angle range defined as -θ2≦θo<-θ1, θ1<θo≦θ2. The second boundary angle θ2 is, for example, within a range from 15 degrees to 30 degrees, and is 30 degrees in this embodiment. If the offset angle θo is within the second angle range A2 (YES), the process proceeds to S80.

[0078] 7, the control unit 52 determines the correction angle θa based on the offset angle θo determined in S72. The correction angle θa is determined so that θa<θo holds when the offset angle θo is a positive value, and so that θo<θa holds when the offset angle θo is a negative value. In this embodiment, the correction angle θa is determined as θa=θ1 when the offset angle θo is a positive value, and as θa=−θ1 when the offset angle θo is a negative value. After S80, the process proceeds to S82.

[0079] In S82, the control unit 52 determines the target angular velocity ω to be applied to the transporter 2 based on the correction angle θa determined in S80. In this embodiment, the target angular velocity ω is determined by the following equation (2) which is based on equation (1) used in S76 and replaces the offset angle θo with the correction angle θa. ω=ωk*θa (2) By specifying the target angular velocity ω from equation (2), it is possible to obtain a target angular velocity ω with a smaller absolute value than when specifying the target angular velocity ω from equation (1) above.

[0080] After S76 or S82, the process proceeds to S84. In S84, the control unit 52 determines the target straight-line speed V to be applied to the transported vehicle 2 based on the distance d to the beacon 82 and the offset angle θo determined in S72. As shown in FIG. 8, the target straight-line speed V here is the straight-line speed in the forward direction FD of the transported vehicle 2. In this embodiment, Equation (3) for deriving the target straight-line speed V from the distance d to the beacon 82 and the offset angle θo is defined as follows: V=min(Vk1*d-Vc1,Vc2-Vk2*θo)...(3) In addition, Vk1 and Vk2 in the equation (3) are predetermined coefficients, and Vc1 and Vc2 are constant terms.

[0081] 7, if the offset angle θo is not within the second angle range A2 (if NO), that is, if the offset angle θo is within the third angle range A3 (see FIG. 8) defined as θo<-θ2, θ2<θo, the process proceeds to S86. In S86, the control unit 52 specifies the target angular velocity ω to be applied to the transporter 2 as ω=0, and specifies the target straight-line velocity V to be applied to the transporter 2 as V=0.

[0082] After S84 or S86, the process proceeds to S88. In S88, the control unit 52 controls the walkie-talkie 2 based on the identified target angular velocity ω and target straight-line speed V. Specifically, the control unit 52 controls the steering motor 36, the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 (see FIG. 2) so that the angular velocity and straight-line speed of the walkie-talkie 2 match the target angular velocity ω and target straight-line speed V. After S88, the process returns to S72.

[0083] In the follow-up operation control process, when the offset angle θo is within the third angle range A3 (see FIG. 8), the control unit 52 specifies ω=0 and V=0 (see S78 in FIG. 7). In this case, the control unit 52 stops the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 to stop the movement (follow-up operation) of the walkie-talkie 2. In other words, when the offset angle θo is within the third angle range A3, the movement (follow-up operation) of the walkie-talkie 2 is prohibited.

[0084] FIG. 9 shows the relationship between the offset angle θo and the turning curvature K of the vehicle 2 during the following operation when the distance d from the vehicle 2 to the beacon 82 is constant, using a solid line. When the offset angle θo is within the first angle range A1 (see FIG. 8), the target angular velocity ω of the vehicle 2 is determined from the above-described equation (1) (see S74 and S76 in FIG. 7). As a result, the turning curvature K increases as the absolute value of the offset angle θo increases. In this embodiment, the turning curvature K when the target angular velocity ω is based on equation (1) is referred to as the "normal turning curvature K(1)." Furthermore, when the offset angle θo is within the second angle range A2 (see FIG. 8), the target angular velocity ω of the vehicle 2 is determined from the above-described equation (2) (see S78, S80, and S82 in FIG. 7). As a result, the turning curvature K remains constant regardless of the value of the offset angle θo. Within the second angle range A2, the turning curvature K when the target angular velocity ω is based on equation (2) is smaller than the normal turning curvature K(1) (see the dashed line in FIG. 9). In this embodiment, the turning curvature K when the target angular velocity ω is based on equation (2) is called the "suppressed turning curvature K(2)."

[0085] The minimum turning radius of the vehicle 2 in the follow-up mode is, for example, within a range of 4339 mm to 15535 mm, and is 7012 mm in this embodiment. The minimum turning radius of the vehicle 2 in the follow-up mode can also be said to be the turning radius when the turning curvature K is the suppressed turning curvature K(2).

[0086] (Processing in manual mode of transport vehicle 2) When the main power supply of the vehicle 2 is ON and the manual mode is selected, the control unit 52 shown in FIG. 2 controls the vehicle 2 based on an operation by the user. Specifically, the control unit 52 determines a target angular velocity ω and a target straight-line speed V to be applied to the vehicle 2 based on the steering angle detected by the steering angle sensor 32, the pull amount of the trigger switch 44, and the traveling speed of the vehicle 2 selected by the speed selector switch 48. The control unit 52 then controls the steering motor 36, the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 so that the angular velocity and straight-line speed of the vehicle 2 match the determined target angular velocity ω and target straight-line speed V. The minimum turning radius of the vehicle 2 in the manual mode is smaller than the minimum turning radius of the vehicle 2 in the follow-up mode, and is 953 mm in this embodiment.

[0087] (Example 2: Transport System 201) The transport system 201 has substantially the same configuration as the transport system 1 of the first embodiment (see FIGS. 1 to 9). The transport system 201 differs from the transport system 1 of the first embodiment only in that the control unit 52 (see FIG. 2) of the transport vehicle 2 executes the process shown in FIG. 10 instead of the process shown in FIG. 7. The process shown in FIG. 10 is a partial modification of the process shown in FIG. 7. The following describes only the changes from the process shown in FIG. 7 among the processes shown in FIG. 10.

[0088] 10, S100 is executed after S82. In S100, the control unit 52 determines the target straight-line speed V to be applied to the transporter 2 based on the distance d to the beacon 82 determined in S72 and the correction angle θa determined in S80. In this embodiment, the target straight-line speed V is determined by the following equation (4) in which the offset angle θo is replaced with the correction angle θa based on equation (3) used in S84. V=min(Vk1*d-Vc1,Vc2-Vk2*θa)...(4) After S100, the process proceeds to S88.

[0089] (Variation) The beacon 82 may be replaced by another communication terminal (for example, a smartphone or a tablet).

[0090] The prime movers that drive the right front wheel 10, left front wheel 12, right rear wheel 14, and left rear wheel 16 of the transporter 2 may be replaced with prime movers other than electric motors (for example, engines equipped with internal combustion engines).

[0091] The operation modes of the transporter 2 do not necessarily have to include a manual mode (or a parking mode). That is, the operation mode of the transporter 2 may be switched between a follow mode and a parking mode (or a manual mode). Alternatively, the operation mode of the transporter 2 may be limited to the follow mode only. In this case, the transporter 2 does not necessarily have to include a mode changeover switch 42.

[0092] 7, the control unit 52 may use a positioning technique other than the positioning technique based on UWB communication to identify the distance d to the beacon 82 and the offset angle θo of the beacon 82. For example, a positioning technique based on Bluetooth (registered trademark) communication or a positioning technique based on Wi-Fi (registered trademark) communication may be used.

[0093] 7, the control unit 52 may specify a target steering angle (the turning angle of the steered wheels with respect to the forward direction FD) to be applied to the steered wheels (right front wheel 10 and left front wheel 12) of the vehicle 2, instead of specifying the target angular velocity ω to be applied to the vehicle 2. In this case, in S88 of FIG. 7, the control unit 52 may adjust the steering angle of the steered wheels to the target steering angle, and then control the steering motor 36, the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 so that the straight-line speed of the vehicle 2 matches the target straight-line speed V.

[0094] The transporter 2 does not need to be equipped with the steering mechanism 34. Even in this case, the transporter 2 can turn by creating a difference between the rotation speeds of the right front wheel 10 and right rear wheel 14 and the left front wheel 12 and left rear wheel 16. For example, in S88 of Fig. 7, the control unit 52 of the transporter 2 may control the rotation speeds of the right front wheel 10, left front wheel 12, right rear wheel 14, and left rear wheel 16 so that the angular velocity and rectilinear velocity of the transporter 2 match the target angular velocity ω and target rectilinear velocity V.

[0095] 7, after the determination in S74 is NO, the process may skip S78 and proceed to S80. That is, even if the offset angle θo is within the third angle range A3, the control unit 52 may continue the movement (following operation) of the transporter 2 without stopping it.

[0096] The beacon 82 does not need to be equipped with the following stop switch 94 (see FIG. 3). Even in this case, the user can indirectly stop the following operation of the vehicle 2 by operating the main power switch 86 (see FIG. 3) to turn off the main power of the beacon 82. This is because turning off the main power of the beacon 82 cuts off communication between the vehicle 2 and the beacon 82, resulting in NO in S36 of FIG. 6, and the vehicle 2 stops the following operation through the subsequent processes of S38, S32, and S34.

[0097] The start instruction transmission termination condition for terminating transmission of the follow-up start instruction from the beacon 82 to the transporter 2 may include a condition other than the operation of the follow-up stop switch 94 (see FIG. 3). For example, the start instruction transmission termination condition may include a condition that a predetermined time has elapsed since the follow-up start switch 92 (see FIG. 3) was operated. Alternatively, the start instruction transmission termination condition may include a condition that the transporter 2 has completed the follow-up operation control process (see FIG. 7).

[0098] The stop instruction transmission termination condition for terminating transmission of the follow-up start instruction from the beacon 82 to the transporter 2 may include a condition other than the follow-up start switch 92 (see FIG. 3) being operated. For example, the stop instruction transmission termination condition may include a condition that a predetermined time has elapsed since the follow-up stop switch 94 (see FIG. 3) was operated. Alternatively, the stop instruction transmission termination condition may include a condition that the transporter 2 has started the follow-up operation control process (see FIG. 7).

[0099] The start operation acceptance period (stop operation acceptance period) may include a period in which the transporter 2 is in manual mode (or parking mode). As a result, operations to the following start switch 92 (see FIG. 3) and the following stop switch 94 (see FIG. 3) may be accepted even during the period in which the transporter 2 is in manual mode (or parking mode).

[0100] The start operation acceptance period (stop operation acceptance period) may include a period in which communication is not established between the transport vehicle 2 and the beacon 82. As a result, even during a period in which communication is not established between the transport vehicle 2 and the beacon 82, an operation to the following start switch 92 (see FIG. 3) and an operation to the following stop switch 94 (see FIG. 3) may be accepted.

[0101] 5, the process of S2 may be omitted. That is, the beacon following flag does not need to be switched OFF immediately after the beacon 82 is powered on or when the following mode is not selected in the transporter 2 (NO in S12).

[0102] The battery 128 (see FIG. 4) may be a non-rechargeable primary battery (for example, a manganese lithium battery). In this case, the battery 128 may be detachable from the beacon 82.

[0103] The battery protection switch circuit 124, the power switch circuit 132, the first charging switch circuit 126, and the second charging switch circuit 138 (see FIG. 4) may each be a mechanical switch.

[0104] The beacon 82 may further include an operation unit (such as a switch) for switching the battery protection switch circuit 124 (see FIG. 4) ON. In this case, in order to switch the battery protection switch circuit 124 from OFF to ON, it may be necessary to operate the operation unit after the beacon 82 is in an external power source operating state.

[0105] (Features of the embodiment) In one or more embodiments, the transporter 2 is capable of autonomously performing a following operation to follow a beacon 82 (an example of a target to be followed). The transporter 2 includes a vehicle body 4, a right front wheel 10, a left front wheel 12, a right rear wheel 14, and a left rear wheel 16 (examples of wheels) supported by the vehicle body 4 and in contact with the ground, a right front wheel motor 24, a left front wheel motor 26, a right rear wheel motor 28, and a left rear wheel motor 30 (examples of prime movers) that drive the right front wheel 10, the left front wheel 12, the right rear wheel 14, and the left rear wheel 16, a communication module 18 and a control unit 52 (an example of an offset angle detection unit) that detect an offset angle θo of the beacon 82 with respect to the forward direction FD of the transporter 2, and the control unit 52. The control unit 52 is configured to be able to perform a following operation control process that controls the following operation of the transporter 2. In the following operation control processing, when the offset angle θo is within a first angle range A1 including 0 degrees, the control unit 52 adjusts the turning curvature K (an example of the degree of turning) of the transporter 2 during the following operation to a normal turning curvature K(1) corresponding to the offset angle θo, and when the offset angle θo is within a second angle range A2 adjacent to the first angle range A1, the control unit 52 adjusts the turning curvature K of the transporter 2 during the following operation to a suppressed turning curvature K(2) that is suppressed more than the normal turning curvature K(1) corresponding to the offset angle θo.

[0106] The larger the absolute value of the offset angle θo, the larger the turning angle required to orient the forward direction FD of the transporter 2 toward the beacon 82. Therefore, it is possible to increase the turning curvature K of the transporter 2. However, if the turning curvature K of the transporter 2 becomes excessively large, the range of travel of the transporter 2 may become excessively large. As a result, the transporter 2 may come into contact with an obstacle, which may hinder the smooth following operation of the transporter 2. According to the above configuration, when the offset angle θo is within the second angle range A2 (i.e., when the absolute value of the offset angle θo is relatively large), the turning curvature K of the transporter 2 is suppressed more than usual. This prevents the turning curvature K of the transporter 2 from becoming excessively large, thereby preventing the range of travel of the transporter 2 from becoming excessively large. This prevents the transporter 2 from coming into contact with an obstacle, thereby allowing the smooth following operation of the transporter 2.

[0107] In one or more embodiments, the turning degree includes a turning curvature K of the transporter 2. In the following operation control process, when the offset angle θo is within the first angle range A1, the control unit 52 adjusts the turning curvature K of the transporter 2 during the following operation to a normal turning curvature K(1) corresponding to the offset angle θo, and when the offset angle θo is within the second angle range A2, the control unit 52 adjusts the turning curvature K of the transporter 2 during the following operation to a suppressed turning curvature K(2) that is reduced below the normal turning curvature K(1) corresponding to the offset angle θo.

[0108] According to the above configuration, when the offset angle θo is within the second angle range A2 (i.e., when the absolute value of the offset angle θo is relatively large), the turning curvature K of the transporter 2 is reduced more than usual. This prevents the turning curvature K of the transporter 2 from becoming excessively large, thereby preventing the range through which the transporter 2 passes from becoming excessively large. This prevents the transporter 2 from coming into contact with an obstacle, allowing the transporter 2 to perform a smooth following operation.

[0109] In one or more embodiments, the vehicle 2 is switchable between a follow mode in which the vehicle is allowed to perform a follow operation and a manual mode in which the vehicle is prohibited from performing a follow operation and moves based on user input. The minimum turning radius of the vehicle 2 in the follow mode is greater than the minimum turning radius of the vehicle 2 in the manual mode.

[0110] As the turning radius of the transporter 2 decreases, the range through which the transporter 2 passes expands. Therefore, in the following mode, in which the user's operation is not involved, if the turning radius of the transporter 2 decreases, the transporter 2 may come into contact with an obstacle. On the other hand, in the manual mode, in which the user's operation is involved, even if the turning radius of the transporter 2 decreases to a certain extent, the transporter 2 is unlikely to come into contact with an obstacle. In fact, if the turning radius of the transporter 2 cannot be reduced in the manual mode, the operability of the transporter 2 may be reduced. According to the above configuration, the minimum turning radius of the transporter 2 in the following mode is larger than the minimum turning radius of the transporter 2 in the manual mode. As a result, the turning radius of the transporter 2 is prevented from being reduced in the following mode, while the turning radius is allowed to be reduced in the manual mode. This makes it possible to prevent the transporter 2 from coming into contact with an obstacle in the following mode without impairing the operability of the transporter 2 in the manual mode.

[0111] In one or more embodiments, in the following operation control process, when the offset angle θo is within a third angle range A3 excluding the first angle range A1 and the second angle range A2, the control unit 52 stops the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30, thereby stopping the following operation of the transporter 2.

[0112] The larger the absolute value of the offset angle θo, the larger the turning angle required to point the forward direction FD of the transport vehicle 2 toward the beacon 82, and therefore the transport vehicle 2 will be forced to make a larger turn. However, if the transport vehicle 2 is turned a large amount, there is a risk that the transport vehicle 2 will come into contact with an obstacle, preventing the transport vehicle 2 from smoothly following the obstacle. According to the above configuration, when the offset angle θo is within the third angle range A3 (i.e., when the absolute value of the offset angle θo is relatively large), the following operation of the transport vehicle 2 is stopped. This prevents the transport vehicle 2 from making a large turn. As a result, the transport vehicle 2 can be prevented from coming into contact with an obstacle, allowing the transport vehicle 2 to smoothly follow the obstacle.

[0113] In one or more embodiments, the transporter 2 is capable of autonomously performing a following operation to follow a beacon 82 (an example of a target to be followed). The transporter 2 includes a vehicle body 4, a right front wheel 10, a left front wheel 12, a right rear wheel 14, and a left rear wheel 16 (examples of wheels) supported by the vehicle body 4 and in contact with the ground, a right front wheel motor 24, a left front wheel motor 26, a right rear wheel motor 28, and a left rear wheel motor 30 (examples of prime movers) that drive the right front wheel 10, the left front wheel 12, the right rear wheel 14, and the left rear wheel 16, a communication module 18 and a control unit 52 (an example of an offset angle detection unit) that detect an offset angle θo of the beacon 82 with respect to the forward direction FD of the transporter 2, and the control unit 52. When the offset angle θo is within a first angle range A1 and a second angle range A2 (examples of operating angle ranges) that include 0 degrees, the control unit 52 operates the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 to cause the transporter 2 to perform a following operation, and when the offset angle θo is within a third angle range A3 (example of a stop angle range) that is adjacent to the first angle range A1 and the second angle range A2, the control unit 52 stops the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 to stop the following operation by the transporter 2.

[0114] The larger the absolute value of the offset angle θo, the larger the turning angle required to orient the forward direction FD of the transport vehicle 2 toward the beacon 82, and therefore the transport vehicle 2 will be forced to make a larger turn. However, if the transport vehicle 2 is turned a larger amount, the transport vehicle 2 may come into contact with an obstacle, which may hinder the smooth following operation of the transport vehicle 2. According to the above configuration, when the offset angle θo is within the first angle range A1 and the second angle range A2 (i.e., when the absolute value of the offset angle θo is relatively small), the following operation of the transport vehicle 2 is performed. When the offset angle θo is within the third angle range A3 (i.e., when the absolute value of the offset angle θo is relatively large), the following operation of the transport vehicle 2 is stopped. This prevents the transport vehicle 2 from making a larger turn. As a result, the transport vehicle 2 is prevented from coming into contact with an obstacle, and the following operation of the transport vehicle 2 can be smoothly performed. [Explanation of symbols]

[0115] 1: Transportation system, 2: Transport vehicle, 4: Body, 6: Loading platform, 8: Handle, 10: Right front wheel, 12: Left front wheel, 14: Right rear wheel, 16: Left rear wheel, 18: Communication module, 20: Battery mounting section, 22: Battery pack, 24: Right front wheel motor, 26: Left front wheel motor, 28: Right rear wheel motor, 30: Left rear wheel motor, 32: Steering angle sensor, 34: Steering mechanism, 36: Steering motor, 38a: Switch box, 38b: Switch box, 40: Main power switch, 42: Mode selector switch, 44: Trigger switch, 46: Direction selector switch, 48: Speed ​​selector switch, 50: Control power circuit, 52: Control unit, 54: Motor driver, 56: Motor driver, 58: Motor driver, 60: Motor driver, 62: Motor driver, 64: Brake circuit, 66: Brake circuit, 6 8: Brake circuit, 70: Brake circuit, 82: Beacon, 84: Housing, 86: Main power switch, 88: Initialization switch, 90: Pairing switch, 92: Tracking start switch, 94: Tracking stop switch, 96: Clip part, 98: Ring part, 100: Protrusion, 102: Microcomputer, 104: Power supply IC, 106: Charging IC, 108: Battery protection IC, 110: Battery interface, 112: USB port, 114: First conductive path, 116: Second conductive path, 118: Third conductive path, 120: Connection point, 122: Fuse, 124: Battery protection switch circuit, 126: First charging switch circuit, 128: Battery, 130: Regulator, 132: Power switch circuit, 134: Communication module, 136: Fuse, 138: Second charging switch circuit, 201: Transport system

Claims

1. A transporter capable of autonomously performing a following operation to follow a target, The car body and wheels supported on the vehicle body and in contact with the ground; a prime mover that drives the wheels; an offset angle detection unit that detects an offset angle of the target to be followed relative to a forward direction of the transporter; a control unit; and the control unit is configured to be able to execute a following operation control process for controlling the following operation of the transporter, In the following operation control process, the control unit: If the offset angle is within a first angle range including 0 degrees, adjusting the turning angle of the transporter during the following operation to a normal turning angle corresponding to the offset angle; When the offset angle is within a second angle range adjacent to the first angle range, the turning angle of the transporter during the following operation is adjusted to a suppressed turning angle that is more suppressed than the normal turning angle corresponding to the offset angle.

2. The turning angle includes a turning curvature of the transporter; In the following operation control process, the control unit: If the offset angle is within the first angle range, adjusting the turning curvature during the following movement of the transporter to a normal turning curvature corresponding to the offset angle; 2. The transporter of claim 1, wherein when the offset angle is within the second angle range, the turning curvature of the transporter during the following operation is adjusted to a suppressed turning curvature that is reduced compared to the normal turning curvature corresponding to the offset angle.

3. the transporter is switchable between a following mode in which execution of the following operation is permitted and a manual mode in which execution of the following operation is prohibited and the transporter moves based on an operation by a user; 3. The vehicle of claim 1, wherein a minimum turning radius of the vehicle in the follow mode is greater than a minimum turning radius of the vehicle in the manual mode.

4. 4. A transporter according to claim 1, wherein in the following operation control process, the control unit stops the prime mover and stops the following operation of the transporter when the offset angle is within a third angle range excluding the first angle range and the second angle range.

5. A transporter capable of autonomously performing a following operation to follow a target, The car body and wheels supported on the vehicle body and in contact with the ground; a prime mover that drives the wheels; an offset angle detection unit that detects an offset angle of the target to be followed relative to a forward direction of the transporter; a control unit; and The control unit When the offset angle is within an operating angle range including 0 degrees, operating the prime mover to cause the transporter to perform the following operation; The vehicle stops the prime mover to stop the following motion of the vehicle when the offset angle is within a stop angle range adjacent to the operating angle range.

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