Carrying vehicle

Abstract

The invention provides a transport vehicle capable of calculating the position of a user with high precision. This transport vehicle is provided with: a vehicle body unit; a ground contact part which is supported by the vehicle body unit and is in contact with the ground; a power machine for driving the grounding part; a first antenna; and a second antenna that is different from the first antenna, the transport vehicle being provided with: a first UWB anchor point that receives a beacon signal from a UWB tag carried by a user; a second UWB anchor point which is different from the first UWB anchor point in position in the front-back direction and which receives a beacon signal from the UWB tag; and a control unit that drives the power machine and is capable of performing following driving that follows the UWB tag and moves the UWB tag. The control unit calculates a first distance between the first UWB anchor point and the UWB tag and a first tag angle of the UWB tag with respect to the first UWB anchor point using the beacon signal received by the first antenna and the beacon signal received by the second antenna.

Description

Technical Field

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

[0002] Japanese Patent Application Laid-Open No. 2023-13129 discloses a transport vehicle comprising: a vehicle body unit; a ground contact portion supported by the vehicle body unit and in contact with the ground; a power unit that drives the ground contact portion; an anchor point that receives a beacon signal from a tag carried by a user; and a control unit that drives the power unit and enables follow-the-tag driving. Summary of the Invention

[0003] In a transport vehicle capable of following a user, it is desirable to accurately calculate the position of a tag, that is, the position of a user. This specification provides a technique for accurately calculating the position of a user.

[0004] The transport vehicle disclosed in this specification includes: a vehicle body unit; a grounding portion supported by the vehicle body unit and in contact with the ground; a power unit that drives the grounding portion; a first antenna; and a second antenna, which is different from the first antenna and may include: a first UWB anchor point that receives a beacon signal from a UWB tag carried by a user; a second UWB anchor point that is located at a different position in the front-to-back direction from the first UWB anchor point and receives the beacon signal from the UWB tag; and a control unit that drives the power unit and is capable of following the UWB tag. The control unit may also calculate a first distance between the first UWB anchor point and the UWB tag, and a first tag angle of the UWB tag relative to the first UWB anchor point, using the beacon signal received by the first antenna and the beacon signal received by the second antenna.

[0005] Effects of the Invention

[0006] According to the above configuration, by using the first UWB anchor point and the second UWB anchor point that are located at different positions in the front-back direction, the position of the UWB tag, that is, the position of the user, can be calculated with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a perspective view showing the transport vehicle 2 according to the first embodiment as viewed from the upper right front.

[0008] Figure 2 It is a left side view of the transport vehicle 2 according to the first embodiment.

[0009] Figure 3 This is a perspective view of the vehicle body unit 4 according to the first embodiment as viewed from the upper right front.

[0010] Figure 4 This is a cross-sectional view of the right front overload monitoring mechanism 26A according to the first embodiment as viewed from the upper right front.

[0011] Figure 5 This is a diagram showing a control configuration of the transport vehicle 2 according to the first embodiment.

[0012] Figure 6 This is a right sectional view of the housing 72 according to the first embodiment.

[0013] Figure 7 This is a front view of the front UWB anchor point 78 according to the first embodiment.

[0014] Figure 8 This is a front sectional view of the center switch box 98 according to the first embodiment.

[0015] Figure 9 This is a right sectional view of the center switch box 98 according to the first embodiment.

[0016] Figure 10 This is a front view of the rear UWB anchor point 108 according to the first embodiment.

[0017] Figure 11 This is a flowchart of the follow-up mode processing involved in the first embodiment.

[0018] Figure 12 1 is a diagram showing a situation where the UWB tag 200 is in a follow-up driving permission area.

[0019] Figure 13 1 is a diagram showing a transmission path of a beacon signal when the UWB tag 200 is in a follow-up driving prohibited area.

[0020] Figure 14 1 is a diagram showing a situation where the UWB tag 200 is in a follow-up driving prohibited area.

[0021] Figure 15 This is a simulation diagram of the transport vehicle 302 involved in Reference Example 1.

[0022] Figure 16 This is a flowchart of the follow-up mode processing involved in Reference Example 1.

[0023] Figure 17 This is a simulation diagram showing the relationship between the UWB tag 200 and the radio wave intensity in Reference Example 1.

[0024] Figure 18 This is a simulation diagram of the transport vehicle 402 involved in Reference Example 2.

[0025] Figure 19This is a flowchart of the follow-up mode processing involved in Reference Example 2.

[0026] Figure 20 This diagram shows a situation in which the UWB tag 200 in Reference Example 2 is located to the right of the transport vehicle 402 .

[0027] Figure 21 This diagram shows a situation in which the UWB tag 200 in Reference Example 2 is located to the left of the transport vehicle 402 .

[0028] Figure 22 It is an overall perspective view of the transport vehicle 502 involved in the second embodiment.

[0029] Figure 23 This is a block diagram showing the structure of the transport vehicle 502 according to the second embodiment.

[0030] Figure 24 This is an overall perspective view of the beacon 582 involved in Example 2.

[0031] Figure 25 This is a circuit diagram showing the electrical configuration of the beacon 582 according to the second embodiment.

[0032] Figure 26 This is a flowchart of the processing executed by the microcomputer 602 of the beacon 582 when the main power supply of the beacon 582 according to the second embodiment is on.

[0033] Figure 27 This is a flowchart of the processing executed by the control unit 552 of the transport vehicle 502 when the main power of the transport vehicle 502 according to the second embodiment is on and the follow-up mode is selected.

[0034] Figure 28 This is a flowchart of the following operation control process executed by the control unit 552 of the transport vehicle 502 according to the second embodiment.

[0035] Figure 29 This is a diagram schematically showing a first angular range A1, a second angular range A2, and a third angular range A3 as viewed from the transport vehicle 502 according to the second embodiment.

[0036] Figure 30 : is a graph showing an example of the relationship between the offset angle θo of the guided vehicle 502 and the turning curvature K in the following operation of the guided vehicle 502 according to the second embodiment.

[0037] Figure 31 This is a flowchart of the following motion control process executed by the control unit 552 of the transport vehicle 502 according to the third embodiment. DETAILED DESCRIPTION

[0038] Representative, but non-limiting, examples of the present invention are described in detail below with reference to the accompanying drawings. This detailed description is intended only 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. Furthermore, the additional features and inventions disclosed below are intended to provide further improved transport vehicles, methods of manufacturing, and methods of using the same, and may be used independently or in conjunction with other features or inventions.

[0039] In addition, the combinations of features or steps disclosed in the following detailed description are not necessarily required to practice the invention in the broadest sense, and in particular, are described only to illustrate representative embodiments of the invention. Furthermore, the features of the above and following representative embodiments, as well as the features recited in the independent and dependent claims, do not necessarily need to be combined as described, or in the order recited, to provide additional and useful embodiments of the invention.

[0040] All features described in this specification and / or claims are intended to be disclosed individually and independently of the features described in the examples and / or claims as limitations relative to the disclosure in the original application and the specific matters described in the claims. Furthermore, all numerical ranges and groupings or clusters are intended to disclose intermediate configurations as limitations relative to the disclosure in the original application and the specific matters described in the claims.

[0041] In one or more embodiments, a transport vehicle includes: a vehicle body unit; a grounding portion supported by the vehicle body unit and in contact with the ground; a power unit that drives the grounding portion; a first antenna; and a second antenna, which is different from the first antenna and may include: a first UWB anchor point that receives a beacon signal from a UWB tag carried by a user; a second UWB anchor point that is located at a different position in the front-to-rear direction from the first UWB anchor point and receives the beacon signal from the UWB tag; and a control unit that drives the power unit and is capable of following the UWB tag. The control unit may also calculate a first distance between the first UWB anchor point and the UWB tag, and a first tag angle of the UWB tag relative to the first UWB anchor point, using the beacon signal received by the first antenna and the beacon signal received by the second antenna.

[0042] In one or more embodiments, the control unit may use the beacon signal received by the second UWB anchor point to calculate the second distance between the second UWB anchor point and the UWB tag, and then use the first distance and the second distance to determine whether the UWB tag is in the first area or the second area different from the first area.

[0043] According to the above configuration, by using the first and second UWB anchor points that are located at different positions in the front-back direction, it is possible to accurately determine whether the user is located in the first or second area.

[0044] In one or more embodiments, the first UWB anchor point may be configured at a position closer to the front side than the second UWB anchor point. The first antenna and the second antenna may also be arranged in the left-right direction. In the left-right direction, the midpoint between the first antenna and the second antenna may coincide with the position of the center of the second UWB anchor point. The control unit may also determine that the UWB tag is in the first area when the second tag angle between the first imaginary line connecting the first UWB anchor point and the UWB tag and the second imaginary line connecting the first UWB anchor point and the second UWB anchor point is an obtuse angle, and determine that the UWB tag is in the second area when the second tag angle is 90° or an acute angle.

[0045] Sometimes, the area where the user is located forward of the first UWB anchor point is designated as the first area, while the area where the user is directly to the side of the first UWB anchor point or further back is designated as the second area. If the second tag angle is an obtuse angle, the user is located forward of the first UWB anchor point. If the second tag angle is 90°, the user is directly to the side of the first UWB anchor point. If the second tag angle is an acute angle, the user is located further back than the first UWB anchor point. This allows for highly accurate determination of the user's location between the first and second areas.

[0046] In one or more embodiments, the first area may be a follow-up driving permission area in which execution of the follow-up driving is permitted, and the second area may be a follow-up driving prohibition area in which execution of the follow-up driving is prohibited.

[0047] According to the above configuration, the user can cause the transport vehicle to execute follow-up driving only when the user is in the follow-up driving permission area.

[0048] In one or more embodiments, the control unit may also use the first distance and the first tag angle to calculate the target speed and target angular velocity when determining that the UWB tag is in the follow-up driving permission area, thereby controlling the operation of the power machine.

[0049] According to the above configuration, when the user is in the follow-up driving permission area, the transport vehicle can be operated so as to follow the user.

[0050] In one or more embodiments, the control unit may also stop the operation of the power machine when it is determined that the UWB tag has moved from the following driving allowed area to the following driving prohibited area, and drive the power machine when it is determined that the UWB tag has moved from the following driving prohibited area to the following driving allowed area.

[0051] According to the above configuration, when the user is in the follow-up driving prohibited area, the guided vehicle can be prevented from traveling, so that the guided vehicle can appropriately perform the follow-up driving.

[0052] In one or more embodiments, the reception sensitivity for signals from the front side of the first UWB anchor point may be greater than the reception sensitivity for signals from the rear side of the first UWB anchor point.

[0053] With this configuration, the likelihood of receiving a beacon signal from a UWB tag in a no-follow-driving zone is low. In this case, if the control unit fails to receive a beacon signal, it can determine that the UWB tag is in the no-follow-driving zone. This makes it easy to determine whether the UWB tag is in the no-follow-driving zone.

[0054] In one or more embodiments, the transport vehicle may further include a cargo platform supported by the vehicle body unit. The front UWB anchor point located in the front of the first UWB anchor point and the second UWB anchor point may be arranged closer to the front of the cargo platform.

[0055] Shelves are loaded with goods. Sometimes, the beacon signal from the UWB tag is blocked by the goods on the shelves, resulting in the front UWB anchor point being unable to receive the beacon signal. With the above configuration, the beacon signal from the UWB tag is not blocked by the goods on the shelves, thereby increasing the probability of the front UWB anchor point receiving the beacon signal.

[0056] In one or more embodiments, the rear UWB anchor point located at the rear position between the first UWB anchor point and the second UWB anchor point is configured at a position closer to the rear than the shelf platform, and the rear UWB anchor point may also be located at a position higher than the front UWB anchor point and the shelf platform.

[0057] Sometimes, the beacon signal from the UWB tag is blocked by the shelf, resulting in the rear UWB anchor point being unable to receive the beacon signal. According to the above configuration, since the signal from the UWB tag is not blocked by the goods placed on the shelf, the probability of the rear UWB anchor point receiving the signal from the UWB tag is increased.

[0058] In one or more embodiments, the transport vehicle may further include a handle having a grip for the user to grip. The handle may be disposed above the cargo platform, and the rear UWB anchor point may be provided on the handle.

[0059] According to the above configuration, the rear UWB anchor point can be easily arranged above the shelf.

[0060] Another transport vehicle disclosed in this specification is capable of performing a following action of autonomously following a following object. The transport vehicle comprises: a vehicle body; wheels supported by the vehicle body and in contact with the ground; a power machine that drives the wheels; an offset angle detection unit that detects the offset angle of the following object relative to the forward direction of the transport vehicle; and a control unit. The control unit is configured to perform a following action control process for controlling the following action of the transport vehicle. In the following action control process, the control unit adjusts the turning degree of the following action of the transport vehicle to a normal turning degree corresponding to the offset angle when the offset angle is within a first angle range including 0 degrees, and adjusts the turning degree of the following action of the transport vehicle to a suppressed turning degree that is suppressed compared to the normal turning degree corresponding to the offset angle when the offset angle is within a second angle range adjacent to the first angle range.

[0061] Since the greater the absolute value of the offset angle, the greater the turning angle required to orient the transporter's forward direction toward the object to be followed, it is possible to consider increasing the turning angle of the transporter. However, when the turning angle of the transporter is too large, the inner wheel difference of the transporter may be too large. As a result, the transporter may come into contact with an obstacle, causing the transporter's following action to be unable to proceed smoothly. According to the above-mentioned configuration, when the offset angle is within the second angle range (that is, when the absolute value of the offset angle is relatively large), the turning angle of the transporter is suppressed compared to the normal situation. Thus, it is possible to suppress the situation where the transporter's turning angle is too large, and therefore, it is possible to suppress the situation where the inner wheel difference of the transporter is too large. Accordingly, it is possible to suppress the situation where the transporter comes into contact with an obstacle, so that the transporter's following action can be performed smoothly.

[0062] Another transport vehicle disclosed in this specification is capable of performing a following action of autonomously following a following object. The transport vehicle comprises: a vehicle body; wheels supported by the vehicle body and in contact with the ground; a power unit that drives the wheels; a deviation angle detection unit that detects the deviation angle of the following object relative to the forward direction of the transport vehicle; and a control unit. When the deviation angle is within an operating angle range including 0 degrees, the control unit activates the power unit and causes the transport vehicle to perform the following action; and when the deviation angle is within a stopping angle range adjacent to the operating angle range, the control unit stops the power unit and stops the following action of the transport vehicle.

[0063] Since the greater the absolute value of the offset angle, the greater the turning angle required to turn the transporter's forward direction toward the object to be followed, the transporter must be made to turn a large turn. However, when the transporter is made to turn a large turn, there is a possibility that the transporter will come into contact with an obstacle, causing the transporter's following action to not be performed smoothly. According to the above-mentioned structure, when the offset angle is within the action angle range (that is, when the absolute value of the offset angle is relatively small), the transporter's following action is performed. When the offset angle is within the stop angle range (that is, when the absolute value of the offset angle is relatively large), the transporter's following action is stopped. Accordingly, it is possible to suppress the transporter from turning a large turn. As a result, it is possible to suppress the transporter from coming into contact with an obstacle, and therefore, the transporter's following action can be performed smoothly.

[0064] The term "turning angle" used in this specification is an indicator of the speed of a truck's turning motion. For example, "turning angle" can be replaced with "the curvature of the truck's turning radius (turn curvature)" or "the steering angle of the steering wheel relative to the truck's forward direction."

[0065] In one or more embodiments, the turning degree may include a turning curvature of the transport vehicle. In the following motion control process, the control unit may adjust the turning curvature of the transport vehicle during the following motion 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 transport vehicle during the following motion to a suppressed turning curvature that is lower than the normal turning curvature corresponding to the offset angle when the offset angle is within the second angle range.

[0066] 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 cart's turning curvature is reduced to a lower value than normal. This prevents the cart's turning curvature from being excessively large, thereby preventing the cart's inner wheel differential from increasing excessively. This prevents the cart from contacting obstacles, allowing for smoother following maneuvers.

[0067] In one or more embodiments, the transport vehicle may be switched between a following mode in which the following action is allowed and a manual mode in which the following action is prohibited and the transport vehicle moves based on a user's operation. The minimum turning radius of the transport vehicle in the following mode may be larger than the minimum turning radius of the transport vehicle in the manual mode.

[0068] When the turning radius of the transport truck becomes smaller, the inner wheel difference of the transport truck increases. Therefore, in the following mode without user intervention, once the turning radius of the transport truck becomes smaller, the transport truck may come into contact with an obstacle. On the other hand, in the manual mode with user intervention, it can be considered that even if the turning radius of the transport truck becomes smaller to a certain extent, the possibility of the transport truck coming into contact with an obstacle will be low. On the contrary, if the turning radius of the transport truck cannot be reduced in the manual mode, the operability of the transport truck may be reduced. According to the above-mentioned structure, the minimum turning radius of the transport truck in the following mode is greater than the minimum turning radius of the transport truck in the manual mode. As a result, the situation of reducing the turning radius of the transport truck in the following mode is suppressed, and the situation of reducing the turning radius in the manual mode is allowed. Accordingly, the operability of the transport truck in the manual mode is not impaired, and the situation of contact between the transport truck and the obstacle in the following mode can be suppressed.

[0069] In one or more embodiments, in the following action control process, the control unit may stop the power machine when the offset angle is within a third angle range other than the first angle range and the second angle range, thereby stopping the following action of the transport vehicle.

[0070] Since the greater the absolute value of the offset angle, the greater the turning angle required to turn the transporter's forward direction toward the object to be followed, the transporter must be made to make a large turn. However, when the transporter makes a large turn, there is a possibility that the transporter will come into contact with an obstacle, causing the transporter's following action to be unable to proceed smoothly. According to the above configuration, when the offset angle is within the third angle range (that is, when the absolute value of the offset angle is relatively large), the transporter's following action is stopped. Accordingly, it is possible to suppress the transporter from making a large turn. As a result, it is possible to suppress the transporter from coming into contact with an obstacle, and therefore, the transporter's following action can be performed smoothly.

[0071] This specification also discloses a transport system. The transport system includes: a transport vehicle and a communication terminal configured to communicate with the transport vehicle. The transport vehicle is configured to perform a following action of following the communication terminal when the communication terminal moves. The communication terminal includes: a first operating part and a second operating part provided at a position different from the first operating part. When the first operating part is operated, the communication terminal switches the power supply ON / OFF. When the power supply is ON and the second operating part is operated during a prescribed start operation acceptance period, the communication terminal sends a following start instruction to the transport vehicle to indicate the start of the following action.

[0072] According to the above configuration, the communication terminal includes a second operating unit for initiating the guided vehicle's following motion, located at a different location from the first operating unit. Even if the first operating unit is operated without the user's consent, the guided vehicle's following motion will not be initiated unless the second operating unit is subsequently operated. This prevents the guided vehicle's following motion from being initiated without the user's consent.

[0073] In one or more embodiments, the communication terminal may further include a third operating unit provided at a position different from the first operating unit and the second operating unit. The communication terminal may transmit a following stop instruction to the transport vehicle to stop the following operation when the third operating unit is operated while the power is on and during a predetermined stop operation acceptance period.

[0074] It is also possible to consider providing the communication terminal with a switching operation unit for accepting the switching of the start / stop of the following action. However, according to this configuration, when the user operates the switching operation unit, it may be unclear to the user whether the communication terminal has instructed the transport vehicle to start or stop the following action. According to the above configuration, the operation unit for accepting the start of the following action (the second operation unit) and the operation unit for accepting the stop of the following action (the third operation unit) are provided separately from each other. Accordingly, when the user operates the second operation unit or the third operation unit, it is clear to the user whether the communication terminal has instructed the transport vehicle to start or stop the following action.

[0075] In one or more embodiments, the communication terminal may continue to send the follow-up stop instruction to the transport vehicle until a specified sending end condition is met when the power supply is on and the third operating unit is operated during the stop operation acceptance period.

[0076] For example, if the communication between the transport vehicle and the communication terminal is poor, the follow-stop instruction sent from the communication terminal may not be received by the transport vehicle. Regardless of whether the transport vehicle receives the follow-stop instruction or not, once the communication terminal stops sending the follow-stop instruction, the transport vehicle's following action will not be stopped and the transport vehicle's following action will continue. According to this configuration, it is possible that the transport vehicle's following action will not be stopped at all regardless of whether the user operates the third operating unit. According to the above configuration, after the third operating unit is operated, the communication terminal continues to send the follow-stop instruction until the transmission end condition is met. This can prevent the transport vehicle's following action from being stopped at all regardless of whether the user operates the third operating unit.

[0077] In one or more embodiments, the transmission end condition may include a first transmission end condition in which the second operating unit is operated.

[0078] According to the above configuration, after the third operating unit is operated, the communication terminal continuously transmits the following stop instruction until the next operation of the second operating unit. This can prevent the following operation of the transport vehicle from being completely stopped regardless of whether the user operates the third operating unit.

[0079] In one or more embodiments, the transport vehicle may be switched between a following mode in which the following action is permitted and a manual mode in which the following action is prohibited and the transport vehicle moves based on a user operation. The start operation acceptance period may also be at least the period in which the transport vehicle is in the following mode.

[0080] Assuming that the period during which the transport vehicle is in manual mode is the period during which operations are accepted, if the second operating unit is operated in manual mode, the transport vehicle's following action may begin when the transport vehicle switches to following mode. Therefore, the start of the transport vehicle's following action may be delayed for a while after the user operates the second operating unit. This may result in the transport vehicle's following action starting at an unintended timing for the user. According to the above configuration, the period during which operations are accepted is at least the period during which the transport vehicle is in following mode. Therefore, even if the second operating unit is operated in manual mode, the operation will not be accepted, and the transport vehicle's following action will not subsequently begin. This prevents the transport vehicle's following action from starting at an unintended timing.

[0081] In one or more embodiments, the start operation acceptance period may be at least a period during which communication between the transport vehicle and the communication terminal is established.

[0082] Assuming that the period during which communication between the transport truck and the communication terminal is interrupted is the period during which the operation is accepted for start, if the second operating unit is operated during this period, the transport truck's following action may begin when communication is subsequently established. Therefore, after the user operates the second operating unit, the start of the transport truck's following action may be delayed for a while. For the user, the transport truck's following action may begin at a time that is not intended by the user. According to the above configuration, the period during which the operation is accepted for start is at least the period during which communication between the transport truck and the communication terminal is established. Therefore, even if the second operating unit is operated during the period during which communication between the transport truck and the communication terminal is interrupted, the operation will not be accepted, and the transport truck's following action will not begin thereafter. This prevents the transport truck's following action from starting at a time that is not intended by the user.

[0083] In one or more embodiments, the communication terminal may transmit a following stop instruction to the transport vehicle to instruct it to stop the following operation immediately after the power is turned on.

[0084] According to the above configuration, the guided vehicle's following operation is stopped immediately after the communication terminal is powered on. Therefore, after the communication terminal is powered on, the guided vehicle's following operation is initiated by operating the second operating unit. This prevents the guided vehicle from starting to follow the user's vehicle regardless of the user's intention.

[0085] This specification also discloses an electrical device comprising: a microcomputer; a battery interface electrically connected to a battery; a first switch circuit that allows power to be supplied to the microcomputer when on but prohibits power to the microcomputer when off; and a second switch circuit that allows discharge from the battery when on but prohibits discharge from the battery when off.

[0086] When the battery is installed in the battery port and the electrical device is left unused for a long time, the remaining battery charge may decrease due to natural discharge. According to the above configuration, in addition to the first switch circuit for switching the permission / prohibition of power supply to the microcomputer (i.e., turning the power on / off), a second switch circuit for switching the permission / prohibition of discharge from the battery is provided. According to this configuration, by turning off the second switch circuit in advance, natural discharge from the battery can be suppressed. Therefore, when the electrical device is left unused for a long time, by turning off the second switch circuit in advance, the remaining battery charge can be suppressed.

[0087] In one or more embodiments, the second switch circuit and the first switch circuit may be arranged in series on a line that supplies power from the battery interface to the microcomputer.

[0088] According to the above configuration, by turning off the second switch circuit in advance, the supply of power to the microcomputer can be prohibited regardless of the ON / OFF state of the first switch circuit.

[0089] In one or more embodiments, the first switching circuit may be an electronic switch. The second switching circuit may also be an electronic switch.

[0090] According to the above configuration, for example, the first switching circuit (second switching circuit) can be miniaturized compared to a case where the first switching circuit (second switching circuit) is a mechanical switch.

[0091] In one or more embodiments, the electrical device may further include a USB port to which a USB cable can be connected, and power may be supplied from the USB cable through the USB port to the electrical device, thereby switching the second switch circuit from OFF to ON.

[0092] According to the above configuration, the second switch circuit can be switched from OFF to ON by a relatively simple operation of connecting the USB cable to the USB port.

[0093] In one or more embodiments, the battery may be a rechargeable secondary battery.

[0094] If the battery is a secondary battery, it is sometimes difficult to remove it from the electrical device. Therefore, when the battery is stored in the electrical device while installed, natural discharge of the battery may occur. In this regard, the above configuration can suppress natural discharge of the battery by pre-setting the second switch circuit to OFF when the electrical device is stored.

[0095] (Example 1)

[0096] Figure 1 The transport vehicle 2 shown in the figure includes a vehicle body unit 4, a cargo platform 6, a handlebar unit 8, and wheels 10. The wheels 10 include a right front wheel 10A, a left front wheel 10B, a right rear wheel 10C, and a left rear wheel 10D (see FIG. Figure 2 The cargo platform 6 , the handlebar unit 8 , the right front wheel 10A, the left front wheel 10B, the right rear wheel 10C, and the left rear wheel 10D are all supported by the vehicle body unit 4 .

[0097] like Figure 3 As shown, the vehicle body unit 4 includes a first front frame 20A, a first rear frame 20B, a right side frame 20C, a left side frame 20D, a second front frame 22A, and a second rear frame 22B. The first front frame 20A, the first rear frame 20B, the second front frame 22A, and the second rear frame 22B extend in the left-right direction. The second front frame 22A is fixed from below to the first front frame 20A at its left and right ends. The second rear frame 22B is fixed from below to the first rear frame 20B at its left and right ends. The right side frame 20C and the left side frame 20D extend in the front-to-back direction. The right side frame 20C and the left side frame 20D connect the first front frame 20A and the first rear frame 20B. The right side frame 20C is positioned to the right of the left-to-right center of the first front frame 20A. The left side frame 20D is arranged on the left side of the center position of the first front side frame 20A in the left-right direction.

[0098] The vehicle body unit 4 further includes a front subframe 24A, a rear subframe 24B, a right subframe 24C, a left subframe 24D, a handlebar support plate 24E, and an overload monitoring mechanism 26. The overload monitoring mechanism 26 includes a right front overload monitoring mechanism 26A, a left front overload monitoring mechanism 26B, a right rear overload monitoring mechanism 26C, and a left rear overload monitoring mechanism 26D.

[0099] The front subframe 24A, rear subframe 24B, right subframe 24C, and left subframe 24D are positioned downwardly from the second front frame 22A and the second rear frame 22B. The front subframe 24A and rear subframe 24B extend in the left-right direction. The right subframe 24C and left subframe 24D extend in the front-back direction. The right subframe 24C connects the right end of the front subframe 24A with the right end of the rear subframe 24B. The front portion of the right subframe 24C is attached to the second front frame 22A via the right front overload monitoring mechanism 26A. The rear portion of the right subframe 24C is attached to the second rear frame 22B via the right rear overload monitoring mechanism 26C. The left subframe 24D connects the left end of the front subframe 24A with the left end of the rear subframe 24B. The front portion of the left subframe 24D is attached to the second front side frame 22A via the left front overload detection mechanism 26B, and the rear portion of the left subframe 24D is attached to the second rear side frame 22B via the left rear overload detection mechanism 26D.

[0100] The right front overload monitoring mechanism 26A, the left front overload monitoring mechanism 26B, the right rear overload monitoring mechanism 26C, and the left rear overload monitoring mechanism 26D all have the same structure. Hereinafter, only the right front overload monitoring mechanism 26A will be described, and the description of the left front overload monitoring mechanism 26B, the right rear overload monitoring mechanism 26C, and the left rear overload monitoring mechanism 26D will be omitted.

[0101] like Figure 4 As shown, the right front overload monitoring mechanism 26A includes a base portion 30 , a buffer member 31 , a housing portion 32 , a cover portion 34 , a shaft 36 , a coil spring 38 , a monitoring plate 40 , and a monitoring sensor 42 .

[0102] The base 30 includes a first cylindrical portion 30A, a first flange portion 30B extending outward from the outer circumference of the first cylindrical portion 30A, and an inner protrusion 30C extending inward from the inner circumference of the lower end of the first cylindrical portion 30A. The inner protrusion 30C defines a first hole 30D having an inner diameter smaller than that of the first cylindrical portion 30A. A buffer member 31 is attached to the upper portion of the base 30.

[0103] The outer shell 32 includes a second cylindrical portion 32A and a second flange portion 32B extending outward from the outer circumferential surface of the upper end of the second cylindrical portion 32A. The inner diameter of the upper portion of the second cylindrical portion 32A is larger than the outer diameter of the first cylindrical portion 30A of the base portion 30. A first frame hole 28A is provided in the front portion of the right sub-frame 24C. The outer diameter of the second cylindrical portion 32A is smaller than the diameter of the first frame hole 28A. The second cylindrical portion 32A extends vertically through the first frame hole 28A. The diameter of the second flange portion 32B is the same as that of the first flange portion 30B of the base portion 30. The diameter of the second flange portion 32B is larger than the diameter of the first frame hole 28A. The lower surface of the first flange portion 30B abuts the upper surface of the second flange portion 32B. The upper surface of the right sub-frame 24C abuts the lower surface of the second flange portion 32B. The cover portion 34 is screwed to the second cylindrical portion 32A from below.

[0104] The shaft 36 includes a first shaft portion 36A, a second shaft portion 36B extending downward from the lower end of the first shaft portion 36A, and a third shaft portion 36C extending downward from the lower end of the second shaft portion 36B. A second frame hole 28B is provided at the right end of the second front frame 22A. The first shaft portion 36A vertically extends through the second frame hole 28B. The diameter of the second shaft portion 36B is larger than that of the first shaft portion 36A. The second shaft portion 36B is vertically slidable within the first cylindrical portion 30A of the base 30. The diameter of the third shaft portion 36C is smaller than that of the second shaft portion 36B. An upper bolt hole 36D is provided in the upper portion of the shaft 36, and a lower bolt hole 36E is provided in the lower portion. A first bolt 44, with a washer 46 attached, is screwed into the upper bolt hole 36D. A second bolt 48 is screwed into the lower bolt hole 36E via the monitoring plate 40. Coil spring 38 is disposed between third shaft portion 36C and first cylindrical portion 30A of base portion 30 . The upper end of coil spring 38 abuts against the lower surface of second shaft portion 36B, and the lower end of coil spring 38 abuts against the upper surface of inner protrusion 30C of base portion 30 .

[0105] The monitoring plate 40 includes a circular plate portion 40A having a second hole 40B in its center, and a monitoring portion 40C. The monitoring portion 40C extends downward from both the front and rear ends of the circular plate portion 40A. The circular plate portion 40A is vertically positioned between the second bolt 48 and the third shaft portion 36C of the shaft 36. The second bolt 48 secures the monitoring plate 40 to the shaft 36. In other words, the shaft 36 and the monitoring plate 40 move integrally.

[0106] The monitoring sensor 42 is a so-called photointerrupter. The monitoring sensor 42 includes a light emitting element 50 and a light receiving element 52 arranged opposite to each other. The monitoring sensor 42 is turned off when there is no shielding between the light emitting element 50 and the light receiving element 52, and is turned on when there is shielding between the light emitting element 50 and the light receiving element 52. The monitoring sensor 42 is connected to the main control unit 60 (see Figure 5 ) electrical connection. Figure 5 The main control unit 60 applies a pulsed voltage to the light emitting element 50. Specifically, the main control unit 60 switches between a state where the voltage is applied to the light emitting element 50 and a state where the voltage is not applied at every predetermined cycle. As a result, the light emitting element 50 emits light intermittently, or flickers.

[0107] like Figure 4 As shown, when there is no cargo on the shelf platform 6 and no load from the shelf platform 6 acts on the shaft 36, the upper surface of the circular plate portion 40A of the monitoring plate 40 abuts against the lower surface of the inner protrusion 30C of the base portion 30 due to the force of the coil spring 38. In this state, the monitoring portion 40C of the monitoring plate 40 does not block the light emitting element 50 and the light receiving element 52. Therefore, the light receiving element 52 receives intermittent light from the light emitting element 50. In this case, the monitoring sensor 42 sends an on signal and an off signal at each specified cycle. Moreover, Figure 5 The main control unit 60 determines that no overload has occurred when it receives an on signal and an off signal from the monitoring sensor 42 at every predetermined period.

[0108] In addition, Figure 4 In the state shown, when the goods are loaded on the shelf platform 6 and the load from the shelf platform 6 acts on the second front side frame 22A, the shaft 36 and the monitoring plate 40 will overcome the force of the coil spring 38 and move downward relative to the base portion 30. At this time, when a load above the specified upper limit load acts on the shaft 36, the monitoring portion 40C of the monitoring plate 40 will be arranged between the light emitting element 50 and the light receiving element 52. Accordingly, the light from the light emitting element 50 is blocked by the monitoring portion 40C. Therefore, the light receiving element 52 does not receive light. In this case, the monitoring sensor 42 will continuously send a disconnection signal to the main control unit 60 (refer to Figure 5 ). In addition, if the electrical wiring connected to the light emitting element 50 is disconnected, the light emitting element 50 will not emit light, and the light receiving element 52 will not receive light. In this case, the monitoring sensor 42 will also continue to send a disconnection signal to the main control unit 60 (refer to Figure 5 ).therefore, Figure 5When the main control unit 60 continuously receives the disconnection signal from the monitoring sensor 42, it determines that an overload has occurred or the electrical wiring is disconnected.

[0109] In addition, in Figure 4 In the event that a short circuit occurs in the connector connected to the light emitting element 50, the light emitting element 50 emits continuous light instead of intermittent light. In this case, the light receiving element 52 receives the continuous light from the light emitting element 50, and the monitoring sensor 42 continuously sends the on signal to the main control unit 60 (refer to Figure 5 ).and, Figure 5 When the main control unit 60 continuously receives the ON signal from the monitoring sensor 42 , it determines that a short circuit has occurred in the connector or the like.

[0110] The following describes a scenario where the light-emitting element 50 continuously emits light in a normal state, with no abnormalities such as disconnection or short circuit. In this case, the light-emitting element 50 continuously emits light when there is no overload and when there is a short circuit. Consequently, the main control unit 60 cannot distinguish between no overload and a short circuit when continuously receiving an on signal from the monitoring sensor 42. With the above configuration, the main control unit 60 can accurately distinguish between no overload, an overload, and some abnormality based on the information received from the monitoring sensor 42.

[0111] like Figure 1 As shown in FIG. 1 , the transport vehicle 2 further includes a buffer member 70 mounted on the front portion of the vehicle body unit 4, a housing 72, a right headlight 73A, and a left headlight 73B. Figure 2 As shown, the cushioning member 70 and the housing 72 are arranged in front of the cargo platform 6. The housing 72 is arranged above the cushioning member 70. The front end of the housing 72 is located rearward of the front end of the cushioning member 70. The right headlight 73A is arranged on the right side of the cushioning member 70. The left headlight 73B is arranged on the left side of the cushioning member 70.

[0112] like Figure 6 As shown, the housing 72 is composed of a first front housing 74 and a first rear housing 76 fixed to the first front housing 74. The housing 72 houses a front UWB anchor 78. The front UWB anchor 78 complies with the UWB (UltraWideBand) standard. In the left-right direction, the center of the front UWB anchor 78 is aligned with the position of the transport vehicle 2. Figure 7 As shown, the front UWB anchor point 78 includes: a UWB substrate 80, a first antenna 82, a second antenna 84, an anchor point control unit 86, and a shield 88 (see Figure 6). The first antenna 82, the second antenna 84, and the anchor point control unit 86 are arranged on the front surface of the UWB substrate 80. The first antenna 82 and the second antenna 84 are arranged at a position that is upward than the anchor point control unit 86. The first antenna 82 and the second antenna 84 are arranged side by side in the left-right direction. In the left-right direction, the midpoint between the first antenna 82 and the second antenna 84 coincides with the position of the center of the transport vehicle 2 and the position of the center of the front UWB anchor point 78. The first antenna 82 is arranged at a position that is to the right of the center position of the UWB substrate 80 in the left-right direction. The second antenna 84 is arranged at a position that is to the left of the center position of the UWB substrate 80 in the left-right direction. As shown Figure 6 As shown, shield 88 is disposed on the rear surface of UWB substrate 80. Shield 88 shields signals transmitted from the rear side of front UWB anchor point 78. Shield 88 reduces the reception sensitivity for signals from the front side of front UWB anchor point 78 compared to the reception sensitivity for signals from the rear side.

[0113] like Figure 1 As shown, the handlebar unit 8 includes a fixed shaft 90, a connecting member 92, a support shaft 94, a handlebar portion 96, a center switch box 98, and a right switch box 100. The fixed shaft 90 is fixed to the handlebar support plate 24E of the vehicle body unit 4 and extends upward from the handlebar support plate 24E. The support shaft 94 extends in the vertical direction. The support shaft 94 is positioned rearward of the fixed shaft 90. The support shaft 94 is rotatably connected to the fixed shaft 90 via the connecting member 92.

[0114] like Figure 8 As shown in FIG. 1 , the handlebar portion 96 is mounted on the upper end of the support shaft 94. Figure 1 As shown in FIG. 1 , the handlebar portion 96 includes a right grip body 96A and a left grip body 96B. The central switch box 98 is provided at the center of the handlebar portion 96 in the left-right direction. Figure 9 As shown, the central switch box 98 is composed of a second front housing 102, a second rear housing 104 fixed to the second front housing 102, and an upper plate 106 sandwiched between the second front housing 102 and the second rear housing 104. The rear UWB anchor point 108 is housed in the central switch box 98. The rear UWB anchor point 108 complies with the UWB standard. That is, the left-right center position of the rear UWB anchor point 108 is aligned with the front UWB anchor point 78 (see FIG. 1 ). Figure 3 ) are aligned with the center in the left and right directions. Figure 10 As shown, the rear UWB anchor point 108 includes: a UWB substrate 110, a third antenna 112, a fourth antenna 114, an anchor point control unit 116, and a shield 118 (see Figure 9). The third antenna 112, the fourth antenna 114, and the anchor point control unit 116 are arranged on the front surface of the UWB substrate 110. The third antenna 112 and the fourth antenna 114 are arranged at a position lower than the anchor point control unit 116. The third antenna 112 and the fourth antenna 114 are arranged side by side in the left-right direction. In the left-right direction, the midpoint between the third antenna 112 and the fourth antenna 114 coincides with the position of the center of the transport vehicle 2 and the position of the center of the rear UWB anchor point 108. The third antenna 112 is arranged at a position closer to the right than the center position of the UWB substrate 110 in the left-right direction. The fourth antenna 114 is arranged at a position closer to the left than the center position of the UWB substrate 110 in the left-right direction. As shown Figure 9 As shown, the shield 118 is disposed on the rear surface of the UWB substrate 110. The shield 118 is a component that shields the signal sent from the rear side of the rear UWB anchor point 108. The receiving sensitivity for the signal from the front side of the rear UWB anchor point 108 is lower than the receiving sensitivity for the signal from the rear side of the front UWB anchor point 78 due to the shield 118. Figure 2 As shown, the center switch box 98 is located above the housing 72 and the shelf 6. That is, the rear UWB anchor point 108 in the center switch box 98 is located above the front UWB anchor point 78 in the housing 72 and the shelf 6.

[0115] like Figure 1 As shown, the right switch box 100 is arranged between the right grip body 96A and the center switch box 98. A tail light 101 is provided at the lower portion of the right switch box 100. Figure 5 As shown, the right switch box 100 is also provided with a main power switch 120, a travel direction switch 122, and a speed switch 124. The main power switch 120 can switch the main power of the transport vehicle 2 on and off. The travel direction switch 122 can switch the travel direction of the transport vehicle 2 in manual mode. The speed switch 124 can switch the travel speed of the transport vehicle 2 in manual mode. In addition, the center switch box 98 is provided with a mode switch 126 and an emergency stop switch 128. The mode switch 126 can switch the operation mode of the transport vehicle 2 between manual mode, follow mode, and parking mode. The emergency stop switch 128 can stop the movement of the transport vehicle 2.

[0116] The user is holding it with both hands Figure 1 The handle unit 8 can be rotated while the right grip body 96A and the left grip body 96B of the handle unit 8 are in the state. Figure 5As shown, the transport vehicle 2 includes a handlebar angle sensor 130 that detects the rotation angle of the handlebar unit 8 as a handlebar angle, a steering mechanism 132 that steers the right front wheel 10A and the left front wheel 10B as steering wheels, and a steering motor 134 that drives the steering mechanism 132. The steering motor 134 is, for example, a brushless motor. The handlebar angle sensor 130, the steering mechanism 132, and the steering motor 134 are supported by the vehicle body unit 4 (see FIG. Figure 1 ).

[0117] like Figure 1 As shown, the transport vehicle 2 includes a battery mounting portion 136 provided on the vehicle body unit 4. A battery pack 138 (see Figure 5 ) is attachable and detachable to the battery mounting portion 136. The battery pack 138 includes secondary battery cells (not shown), such as lithium-ion battery cells, and is rechargeable using a charger (not shown). The transport vehicle 2 operates using power supplied by the battery pack 138 mounted on the battery mounting portion 136.

[0118] like Figure 5 As shown, the transport vehicle 2 includes a travel motor 140. The travel motor 140 includes a right front wheel motor 140A that drives the right front wheel 10A, a left front wheel motor 140B that drives the left front wheel 10B, a right rear wheel motor 140C that drives the right rear wheel 10C, and a left rear wheel motor 140D that drives the left rear wheel 10D. The right front wheel motor 140A, the left front wheel motor 140B, the right rear wheel motor 140C, and the left rear wheel motor 140D are, for example, brushless motors. The right front wheel motor 140A, the left front wheel motor 140B, the right rear wheel motor 140C, and the left rear wheel motor 140D are supported by the vehicle body unit 4 (see FIG. 4 ). Figure 1 ).

[0119] The transport vehicle 2 also includes a control power circuit 150. When the main power switch 120 is turned on, the control power circuit 150 allows power to be supplied from the battery pack 138. When the main power switch 120 is turned off, the control power circuit 150 prohibits power from being supplied from the battery pack 138. The main control unit 60 controls the operation of the transport vehicle 2. The main control unit 60 controls the operation of the right front wheel motor 140A, the left front wheel motor 140B, the right rear wheel motor 140C, the left rear wheel motor 140D, and the steering motor 134 via motor drivers 160, 162, 164, 166, and 168. Although not shown, brake circuits are connected to the motor drivers 160, 162, 164, and 166, corresponding to the right front wheel motor 140A, the left front wheel motor 140B, the right rear wheel motor 140C, and the left rear wheel motor 140D. The main control unit 60 can apply a large braking force to the right front wheel motor 140A, the left front wheel motor 140B, the right rear wheel motor 140C, and the left rear wheel motor 140D by flowing a large current through the brake circuit during the rotation of the right front wheel motor 140A, the left front wheel motor 140B, the right rear wheel motor 140C, and the left rear wheel motor 140D. The control power supply circuit 150, the main control unit 60, the motor drivers 160, 162, 164, 166, and 168, and the brake circuit are supported by the vehicle body unit 4 (see FIG. Figure 1 ).

[0120] The main control unit 60 is further electrically connected to the four monitoring sensors 42 , the front UWB anchor point 78 , and the rear UWB anchor point 108 .

[0121] Figure 1 The transport vehicle 2 can operate in one of the following modes: manual mode, following mode, or parking mode. In manual mode, the transport vehicle 2 moves forward or backward according to the user's operation when the user standing behind the vehicle body unit 4 holds the handle unit 8 with both hands. In following mode, the transport vehicle 2 tracks the UWB tag 200 carried by the user standing in front of the vehicle body unit 4 (see Figure 12 ) and moves. In parking mode, the transport vehicle 2 does not accept any instructions from the handle unit 8 or the UWB tag 200, but continues to stop on the spot. In addition, the main control unit 60 of the transport vehicle 2 is configured to prohibit the transport vehicle 2 from traveling when it is determined based on the information received from the monitoring sensor 42 that overloading has occurred or that some abnormality has occurred in the transport vehicle 2. That is, traveling in manual mode and follow-up mode is prohibited. In addition, the transport vehicle 2 is in the emergency stop switch 128 (refer to Figure 5 ) is operated, an emergency stop is performed.

[0122] (Follow-up mode processing; Figure 11 )

[0123] Reference Figure 11 The following mode processing executed by the main control unit 60 is described below. When the operation mode of the transport vehicle 2 is set to the following mode, the main control unit 60 starts Figure 11 processing.

[0124] In addition, if Figure 12 As shown, the front UWB anchor point 78 is connected to the first antenna 82 and the second antenna 84 (see Figure 7 ) and receives a beacon signal transmitted from the UWB tag 200, the distance from the front UWB anchor point 78 to the UWB tag 200 (hereinafter referred to as "first distance D1") and the angle of the UWB tag 200 relative to the front UWB anchor point 78 (hereinafter referred to as "first angle a1") are calculated. The first angle a1 is the angle between a straight line L0 extending in the front-to-back direction and a first straight line L1 connecting the front UWB anchor point 78 and the UWB tag 200. Specifically, the front UWB anchor point 78 determines the first distance D1 using the transmission time of the beacon signal received via the first antenna 82, and calculates the first angle a1 using the phase difference between the beacon signal received via the first antenna 82 and the beacon signal received via the second antenna 84. As a method of calculating an angle using a phase difference, PDoA (abbreviation of Phase Differences of Arrival) and AoA (abbreviation of Angle of Arrival) are known.

[0125] In addition, the rear UWB anchor point 108 is connected to the third antenna 112 and the fourth antenna 114 (see Figure 10 ) and receives a beacon signal transmitted from the UWB tag 200, the distance from the rear UWB anchor point 108 to the UWB tag 200 (hereinafter referred to as "second distance D2") and the angle of the UWB tag 200 relative to the rear UWB anchor point 108 (hereinafter referred to as "second angle a2") are calculated. The second angle a2 is the angle between the straight line L0 extending in the front-to-back direction and the second straight line L2 connecting the rear UWB anchor point 108 and the UWB tag 200. The calculation methods for the second distance D2 and the second angle a2 are the same as the calculation methods for the first distance D1 and the first angle a1, respectively.

[0126] exist Figure 11In S10, the main control unit 60 acquires the first distance D1 and the first angle a1 from the front UWB anchor point 78. Specifically, in response to providing a first acquisition instruction for acquiring the first distance D1 and the first angle a1 to the front UWB anchor point 78, the main control unit 60 acquires the first distance D1 and the first angle a1 from the front UWB anchor point 78. Furthermore, if the front UWB anchor point 78 does not receive a beacon signal from the UWB tag 200, the main control unit 60 acquires non-reception information from the front UWB anchor point 78 indicating that the beacon signal was not received.

[0127] In S12, the main control unit 60 obtains the second distance D2 and the second angle a2 from the rear UWB anchor point 108. Specifically, in response to providing a second acquisition instruction for obtaining the second distance D2 and the second angle a2 to the rear UWB anchor point 108, the main control unit 60 obtains the second distance D2 and the second angle a2 from the rear UWB anchor point 108. Furthermore, if the rear UWB anchor point 108 does not receive a beacon signal from the UWB tag 200, the main control unit 60 obtains non-reception information from the rear UWB anchor point 108 indicating that the beacon signal was not received.

[0128] In S20, the main control unit 60 determines whether the UWB tag 200 is in the follow-up driving permission area. The follow-up driving permission area is an area where the execution of follow-up driving by tracking the UWB tag 200 is permitted. Figure 12 As shown, the following driving permission area is the area forward of the front UWB anchor point 78. Furthermore, the area directly to the side of the front UWB anchor point 78 and the area rearward of the front UWB anchor point 78 are the following driving prohibition areas where following driving is prohibited. The main control unit 60 uses the first distance D1 obtained from the front UWB anchor point 78, the second distance D2 obtained from the rear UWB anchor point 108, and the third distance D3 between the front UWB anchor point 78 and the rear UWB anchor point 108 to determine whether the UWB tag 200 is in the following driving permission area. Furthermore, the third distance D3 is pre-stored in the memory of the main control unit 60 (not shown). The main control unit 60 calculates the third angle a3 using the first distance D1, the second distance D2, the third distance D3, and the following equation (1). The third angle a3 is the angle between the first straight line L1 and a third straight line L3 connecting the front UWB anchor point 78 and the rear UWB anchor point 108. In this embodiment, the third straight line L3 is parallel to the straight line L0.

[0129] (Formula 1)

[0130]

[0131] Reference Figure 12, which illustrates the case where the UWB tag 200 is located forward of the front UWB anchor point 78. In this case, the third angle a3 is obtuse, corresponding to the second distance D2 being longer than the first distance D1. Therefore, when the third angle a3 is obtuse, it can be determined that the UWB tag 200 is in the following driving permission area.

[0132] Reference Figure 13 、 Figure 14 , which illustrates the case where the UWB tag 200 is located at a position closer to the rear side than the front UWB anchor point 78. In this embodiment, the front UWB anchor point 78 and the rear UWB anchor point 108 each have: a shielding member 88 (see Figure 6 ), 118 (refer to Figure 9 ). Therefore, if Figure 13 As shown, the first antenna 82 and the second antenna 84 of the front UWB anchor point 78 and the third antenna 112 and the fourth antenna 114 of the rear UWB anchor point 108 do not receive most of the beacon signals transmitted from the rear side of the front UWB anchor point 78 and the rear UWB anchor point 108 ( Figure 13 However, the beacon signals from the rear side of the front UWB anchor point 78 and the rear UWB anchor point 108 may sometimes go around to the front side of the front UWB anchor point 78 and the rear UWB anchor point 108 and reach the first antenna 82 and the second antenna 84 of the front UWB anchor point 78 and the third antenna 112 and the fourth antenna 114 of the rear UWB anchor point 108 ( Figure 13 solid arrow). Figure 14 This figure is provided to facilitate understanding of the following situation: the beacon signal transmitted from the rear side of the front UWB anchor point 78 and the rear UWB anchor point 108 goes around to the front side of the front UWB anchor point 78 and the rear UWB anchor point 108 and reaches the first antenna 82 and the second antenna 84 of the front UWB anchor point 78 and the third antenna 112 and the fourth antenna 114 of the rear UWB anchor point 108. In this case, Figure 14 As shown, the third angle a3 is an acute angle corresponding to the first distance D1 being longer than the second distance D2. Therefore, the third angle a3 can be used to determine that the UWB tag 200 is in the no-following driving zone. Furthermore, the third angle a3 is also acute when the UWB tag 200 is located forward of the front UWB anchor point 78 and rearward of the rear UWB anchor point 108.

[0133] return Figure 11In S20, if the third angle a3 is an obtuse angle, the main control unit 60 determines that the UWB tag 200 is located forward of the front UWB anchor point 78. In this case, the main control unit 60 determines that the UWB tag 200 is in the following driving permitted area (YES in S20), and the process proceeds to S22. On the other hand, if the third angle a3 is not an obtuse angle, the main control unit 60 determines that the UWB tag 200 is located forward of the front UWB anchor point 78. In this case, the main control unit 60 determines that the UWB tag 200 is in the following driving prohibited area (NO in S20), and the process proceeds to S30.

[0134] Furthermore, if the main control unit 60 receives no reception information from the front UWB anchor point 78 in S10, or receives no reception information from the rear UWB anchor point 108 in S12, it determines that the UWB tag 200 is in the following driving prohibited area (NO in S20), and the process proceeds to S30. If no reception information is received, it is likely that the UWB tag 200 is located further rearward than the front UWB anchor point 78 or the rear UWB anchor point 108.

[0135] In S22 , the main control unit 60 uses the first distance D1 and the first angle a1 acquired from the front UWB anchor point 78 to determine the target velocity TV and target angular velocity Tω of the transport vehicle 2 so that the transport vehicle 2 tracks the UWB tag 200 .

[0136] In S24, the main control unit 60 controls the movement of the transport vehicle 2. Specifically, based on the target velocity TV and the target angular velocity Tω, the main control unit 60 controls the movement of the right front wheel motor 140A, the left front wheel motor 140B, the right rear wheel motor 140C, the left rear wheel motor 140D, and the steering motor 134. When S24 ends, the process returns to S10. For example, if the UWB tag 200 moves from the following driving prohibited area to the following driving permitted area while the transport vehicle 2 is stopped, the main control unit 60 controls the movement of the right front wheel motor 140A, the left front wheel motor 140B, the right rear wheel motor 140C, the left rear wheel motor 140D, and the steering motor 134 to cause the transport vehicle 2 to travel.

[0137] Furthermore, in S30, the main control unit 60 determines the target speed TV and the target angular speed Tω of the transport vehicle 2 to be zero. When S30 is completed, the process proceeds to S24.

[0138] In S24, following S30, the main control unit 60 controls the operation of the transport vehicle 2 so that the transport vehicle 2 does not travel. For example, if the UWB tag 200 moves from the following driving permitted area to the following driving prohibited area while the transport vehicle 2 is traveling, the main control unit 60 controls the operation of the brake circuit to stop the transport vehicle 2. Furthermore, if the UWB tag 200 moves from the following driving permitted area to the following driving prohibited area while the transport vehicle 2 is stopped, the main control unit 60 stops driving the right front wheel motor 140A, the left front wheel motor 140B, the right rear wheel motor 140C, the left rear wheel motor 140D, and the steering motor 134.

[0139] As described above, the main control unit 60 uses the first distance D1, the second distance D2, and the third distance D3 to accurately determine whether the UWB tag 200 is in the tailgating driving permitted area. Therefore, if the UWB tag 200 is in the tailgating driving prohibited area, tailgating driving can be prevented from being executed.

[0140] Hereinafter, the main control unit 60 and the anchor point control units 86 and 116 are collectively referred to as a “control unit”.

[0141] In one or more embodiments, the transport vehicle 2 includes: a body unit 4, wheels 10 supported by the body unit 4 and in contact with the ground (an example of a "grounding portion"), a travel motor 140 that drives the wheels 10 (an example of a "power machine"), a first antenna 82, and a second antenna 84, and is provided with: a front UWB anchor point 78 (an example of a "first UWB anchor point") that receives a beacon signal from a UWB tag 200 carried by a user; a rear UWB anchor point 108 (an example of a "second UWB anchor point") that is arranged at a position farther rearward than the front UWB anchor point 78 and receives a beacon signal from the UWB tag 200; and a control unit that drives the travel motor 140 to perform following driving in which the vehicle moves following the UWB tag 200. The control unit uses the beacon signal received by the first antenna 82 and the beacon signal received by the second antenna 84 to calculate the first distance D1 between the front UWB anchor point 78 and the UWB tag 200, and the first angle a1 of the UWB tag 200 relative to the front UWB anchor point 78 (an example of a “first tag angle”).

[0142] According to the above configuration, the position of the UWB tag 200 , that is, the position of the user, can be calculated with high accuracy using the front UWB anchor point 78 and the rear UWB anchor point 108 , which are located at different positions in the front-back direction.

[0143] In one or more embodiments, the control unit uses the beacon signal received by the rear UWB anchor point 108 to calculate the second distance D2 between the rear UWB anchor point 108 and the UWB tag 200, and uses the first distance D1 and the second distance D2 to determine whether the UWB tag 200 is located in an area where the execution of follow-up driving is allowed, that is, a follow-up driving allowed area (an example of a "first area") and a follow-up driving prohibited area (an example of a "second area") where the execution of follow-up driving is prohibited.

[0144] With this configuration, the front UWB anchor point 78 and the rear UWB anchor point 108, which are positioned differently in the front-to-back direction, can accurately determine whether the user is in the follow-up driving permitted area or the follow-up driving prohibited area. Furthermore, with this configuration, the transport vehicle 2 can be caused to execute follow-up driving only when the user is in the follow-up driving permitted area.

[0145] In one or more embodiments, the front UWB anchor point 78 is positioned forward of the rear UWB anchor point 108. The first antenna 82 and the second antenna 84 are aligned in the left-right direction. In the left-right direction, the midpoint between the first antenna 82 and the second antenna 84 coincides with the center of the rear UWB anchor point 108. The control unit determines that the UWB tag 200 is in the tailgating driving permitted area if the third angle a3 (an example of a "second tag angle") between the first straight line L1 (an example of a "first imaginary line") connecting the front UWB anchor point 78 and the UWB tag 200 and the third straight line L3 (an example of a "second imaginary line") connecting the front UWB anchor point 78 and the rear UWB anchor point 108 is an obtuse angle. If the third angle a3 is 90° or an acute angle, the control unit determines that the UWB tag 200 is in the tailgating driving prohibited area.

[0146] The area where the user is located forward of the front UWB anchor point 78 is designated as the follow-up driving permitted area. The area where the user is located directly to the side of or rearward of the front UWB anchor point 78 is designated as the follow-up driving prohibited area. If the third angle a3 is an obtuse angle, the user is located forward of the front UWB anchor point 78. If the third angle a3 is 90°, the user is located directly to the side of the front UWB anchor point 78. If the third angle a3 is an acute angle, the user is located rearward of the front UWB anchor point 78. This allows for highly accurate determination of whether the user is located in the follow-up driving permitted area or the follow-up driving prohibited area.

[0147] In one or more embodiments, when the control unit determines that the UWB tag 200 is in the following driving permission area, it calculates the target speed TV and the target angular speed Tω using the first distance D1 and the first angle a1 to control the operation of the driving motor 140 .

[0148] According to the above configuration, when the user is in the follow-up driving permission area, the transport vehicle 2 can be operated so as to follow the user.

[0149] In one or more embodiments, the control unit stops the operation of the driving motor 140 when it determines that the UWB tag 200 has moved from the following driving allowed area to the following driving prohibited area, and drives the driving motor 140 when it determines that the UWB tag 200 has moved from the following driving prohibited area to the following driving allowed area.

[0150] According to the above configuration, when the user is in the follow-up driving prohibited area, the guided vehicle 2 can be prevented from traveling. Therefore, the guided vehicle 2 can appropriately perform the follow-up driving.

[0151] In one or more embodiments, the reception sensitivity for signals from the front side of the front UWB anchor point 78 is greater than the reception sensitivity for signals from the rear side of the front UWB anchor point 78 .

[0152] With this configuration, the likelihood of receiving a beacon signal from a UWB tag 200 located in a no-following driving zone is low. In this case, the control unit can determine that the UWB tag 200 is located in the no-following driving zone even if no beacon signal is received. This makes it easy to determine whether the UWB tag 200 is in the no-following driving zone.

[0153] In one or more embodiments, the transport vehicle 2 further includes a cargo platform 6 supported by the vehicle body unit 4 . The front UWB anchor point 78 is arranged at a position closer to the front side than the cargo platform 6 .

[0154] When goods are placed on the shelf 6 and the UWB tag is located in front of the transport vehicle 2, and the front UWB anchor point 78 is located further back than the shelf 6, the beacon signal from the UWB tag 200 may be blocked by the goods placed on the shelf 6, resulting in the front UWB anchor point 78 being unable to receive the beacon signal. With the above configuration, since the beacon signal from the UWB tag 200 is not blocked by the goods placed on the shelf 6, the probability of the front UWB anchor point 78 receiving the beacon signal can be increased.

[0155] In one or more embodiments, the rear UWB anchor point 108 is disposed rearward of the shelf 6 . The rear UWB anchor point 108 is disposed upward of the front UWB anchor point 78 and the shelf 6 .

[0156] Sometimes, the beacon signal from the UWB tag 200 is blocked by the shelf 6, resulting in the rear UWB anchor point 108 being unable to receive the beacon signal. According to the above configuration, since the signal from the UWB tag 200 is not blocked by the goods placed on the shelf 6, the probability of the rear anchor point receiving the signal from the UWB tag 200 is increased.

[0157] In one or more embodiments, the transport vehicle 2 further includes a handlebar 96 having grips 96A and 96B for a user to grip. The handlebar 96 is positioned above the cargo platform 6 , and the rear UWB anchor point 108 is provided on the handlebar 96 .

[0158] According to the above configuration, the rear UWB anchor point 108 can be easily arranged above the shelf 6 .

[0159] (First Modification) Either the front UWB anchor point 78 or the rear UWB anchor point 108 may have only one antenna. In this modification, the main control unit 60 controls the movement of the transport vehicle 2 using the distance and angle calculated using the UWB anchor point having two antennas, either the front UWB anchor point 78 or the rear UWB anchor point 108.

[0160] (Second variant) Figure 11 In S22 , the control unit may determine the target speed TV and the target angular speed Tω of the transport vehicle 2 using the second distance D2 and the second angle a2 acquired from the rear UWB anchor point 108 .

[0161] (Third Modification) In the left-right direction, the center position of the front UWB anchor point 78 and the center position of the rear UWB anchor point 108 may not be consistent. In this case, the control unit corrects the deviation between the center position of the front UWB anchor point 78 and the center position of the rear UWB anchor point 108, and performs Figure 11 The S20's processing.

[0162] (Fourth Modification) The control unit may also use the first distance D1 and the second distance D2 to determine whether the UWB tag 200 is in the follow-up driving permission area. For example, the control unit may determine that the UWB tag 200 is in the follow-up driving permission area if the first distance D1 is greater than the second distance D2.

[0163] (Fifth Modification) Even when the operation mode of the transport vehicle 2 is the manual mode or the parking mode, the control unit can determine whether the UWB tag 200 is in the follow-up driving permission area.

[0164] (Sixth Modification) At least one or both of the front UWB anchor point 78 and the rear UWB anchor point 108 may not include the shielding members 88 and 118 .

[0165] (Seventh Modification) Both the front UWB anchor point 78 and the rear UWB anchor point 108 may be located either forward or rearward of the shelf 6. Furthermore, at least one of the front UWB anchor point 78 and the rear UWB anchor point 108 may be located to the side of the shelf 6.

[0166] (Eighth Modification) The "power machine" is not limited to the travel motor 140, and may be an engine or the like.

[0167] (Ninth Modification) The "ground contact portion" is not limited to a wheel, and may be a crawler track or the like.

[0168] (Tenth Modification) The area forward of the front UWB anchor point 78 can be a forward tracking area, where the transport vehicle 2 moves forward and follows the UWB tag 200. The area rearward of the front UWB anchor point 78 can be a backward driving area, where the transport vehicle 2 moves backward and follows the UWB tag 200. In this case, the area directly to the side of the front UWB anchor point 78 can be a stop area, where following is not performed. In this modification, the "forward tracking area" and the "backward tracking area" are examples of the "first area" and the "second area," respectively.

[0169] (Eleventh Modification) The area forward of the front UWB anchor point 78 may be a front lighting area where the right headlight 73A and the left headlight 73B are illuminated, and the area rearward of the front UWB anchor point 78 may be a rear lighting area where the taillight 101 is illuminated. In this case, the area directly to the side of the front UWB anchor point 78 may be a lights-off area where the right headlight 73A, the left headlight 73B, and the taillight 101 are not illuminated. In this modification, the "front lighting area" and the "rear lighting area" are examples of the "first area" and the "second area," respectively.

[0170] Further features of the transport vehicle 2 disclosed in this embodiment are as follows.

[0171] (Feature 1-1)

[0172] A monitoring device comprising: a light emitting element, a light receiving element arranged opposite to the light emitting element, a shielding plate capable of shielding light emitted from the light emitting element, and a control unit.

[0173] The control unit applies a pulsed voltage to the light emitting element in such a manner that the light emitting element intermittently emits light.

[0174] The light receiving element intermittently receives the light emitted from the light emitting element when the shielding plate does not block the light emitted from the light emitting element, and does not receive the light emitted from the light emitting element when the shielding plate blocks the light emitted from the light emitting element.

[0175] (Features 1-2)

[0176] In the monitoring device according to feature 1-1, the light receiving element continuously receives the light emitted from the light emitting element when a short-circuit abnormality occurs in the light emitting element and the shielding plate does not block the light emitted from the light emitting element.

[0177] (Features 1-3)

[0178] A transport vehicle comprising: a platform, a grounding portion contacting the ground, a power machine for driving the grounding portion, a monitoring device according to feature 1-1 or 1-2 mounted on the platform, and a control unit for controlling the operation of the power machine.

[0179] The control unit allows the driving of the power machine when the light receiving element of the monitoring device intermittently receives the light emitted from the light emitting element, and prohibits the driving of the power machine when the light receiving element does not receive the light emitted from the light emitting element.

[0180] (Features 1-4)

[0181] In the transport vehicle according to features 1-3, when a load exceeding a predetermined upper limit load acts from the shelf platform on the shielding plate of the monitoring device, the light emitted from the light emitting element of the monitoring device is blocked by the shielding plate.

[0182] When a load smaller than a predetermined upper limit load acts on the shielding plate from the shelf platform, the light emitted from the light emitting element is not blocked by the shielding plate.

[0183] The effects of the above-mentioned features 1-1 to 1-4 will be described.

[0184] In one or more embodiments, the overload monitoring mechanism 26 (an example of a "monitoring device") includes a light-emitting element 50, a light-receiving element 52 disposed opposite the light-emitting element 50, a monitoring plate 40 (an example of a "shielding plate") capable of shielding light emitted from the light-emitting element 50, and a control unit. The control unit applies a pulsed voltage to the light-emitting element 50 so that the light-emitting element 50 intermittently emits light. The light-receiving element 52 intermittently receives light emitted from the light-emitting element 50 when the monitoring plate 40 does not shield the light emitted from the light-emitting element 50, and does not receive light emitted from the light-emitting element 50 when the shielding plate 40 shields the light emitted from the light-emitting element 50.

[0185] According to the above configuration, the control unit can monitor whether the monitoring board 40 blocks the light emitted from the light emitting element 50 according to whether the light receiving element 52 intermittently receives the light emitted from the light emitting element 50 .

[0186] In one or more embodiments, when a short circuit abnormality occurs in the light emitting element 50 and the monitoring board 40 does not block the light emitted from the light emitting element 50 , the light receiving element 52 continues to receive the light emitted from the light emitting element 50 .

[0187] According to the above configuration, the control unit can detect the occurrence of a short-circuit abnormality in the light-emitting element 50 when the light-receiving element 52 continuously receives light emitted from the light-emitting element 50 .

[0188] In one or more embodiments, the transport vehicle 2 includes a cargo platform 6, wheels 10 in contact with the ground (an example of a "grounding portion"), a travel motor 140 (an example of a "power machine") that drives the wheels 10, an overload monitoring mechanism 26 (an example of a "monitoring device") mounted on the cargo platform 6, and a control unit that controls the operation of the travel motor 140. The control unit permits the driving of the travel motor 140 when the light receiving element 52 intermittently receives light emitted from the light emitting element 50, and prohibits the driving of the travel motor 140 when the light receiving element 52 does not receive light emitted from the light emitting element 50.

[0189] If the light receiving element 52 does not receive the light emitted from the light emitting element 50, there is a high probability that some abnormality has occurred in the transport vehicle 2. According to the above configuration, when some abnormality has occurred in the transport vehicle 2, the transport vehicle 2 can be appropriately prevented from traveling.

[0190] In one or more embodiments, when a load greater than a specified upper limit load acts from the shelf platform 6 on the monitoring plate 40 (an example of a "shielding plate"), the light emitted from the light-emitting element 50 is blocked by the monitoring plate 40; and when a load smaller than the specified upper limit load acts from the shelf platform 6 on the monitoring plate 40, the light emitted from the light-emitting element 50 is not blocked by the monitoring plate 40.

[0191] The following describes a scenario where the light-emitting element 50 continuously emits light in a normal state, with no abnormalities such as disconnection or short circuit. In this case, the light-emitting element 50 continuously emits light when there is no overload and when there is a short circuit. Consequently, when the main control unit 60 continuously receives an on signal from the monitoring sensor 42, it cannot distinguish whether there is no overload or a short circuit. With this configuration, the overload monitoring mechanism 26 can accurately determine whether an overload has occurred. Therefore, when an overload occurs, the transport vehicle 2 can be appropriately prevented from traveling.

[0192] (Variation 1-1) The "monitoring device" can be used not only in the transport vehicle 2 but also in a robot cleaner and the like.

[0193] (Reference Example 1) Figures 15 to 17 , explaining the transport vehicle 302 of Reference Example 1. Hereinafter, the differences between the transport vehicle 302 of Reference Example 1 and the transport vehicle 2 of Example 1 will be mainly explained, and the explanation of the common points will be omitted.

[0194] like Figure 15 As shown, the transport vehicle 302 of Reference Example 1 is different from the transport vehicle 2 of Example 1 in that it does not have the rear UWB anchor point 108. In addition, the main control unit 60 of Reference Example 1 (see Figure 5 ) instead Figure 12 Follow-up mode processing is executed Figure 16 Follow-up mode processing.

[0195] (Follow-up mode processing; Figure 16 )Reference Figure 16 , the following mode processing executed by the main control unit 60 is described. When the operation mode of the transport vehicle 302 is set to the following mode, the main control unit 60 starts to perform Figure 16 processing.

[0196] In S110, the main control unit 60 acquires the first distance D1 and the first angle a1 from the front UWB anchor point 78. Specifically, in response to providing a first acquisition instruction for acquiring the first distance D1 and the first angle a1 to the front UWB anchor point 78, the main control unit 60 acquires the first distance D1 and the first angle a1 from the front UWB anchor point 78. Furthermore, if the front UWB anchor point 78 does not receive a beacon signal from the UWB tag 200, the main control unit 60 acquires non-reception information from the front UWB anchor point 78 indicating that the beacon signal was not received.

[0197] In S112, the main control unit 60 uses the first distance D1 obtained in S110 to determine a radio intensity threshold. The radio intensity threshold is used to determine whether the UWB tag 200 is within the tracking driving permission area. The longer the first distance D1, the lower the radio intensity threshold.

[0198] exist Figure 16 In S120, the main control unit 60 determines whether the UWB tag 200 is in the following driving permission area. Specifically, the main control unit 60 determines whether the radio wave intensity of the beacon signal received by the front UWB anchor point 78 exceeds the radio wave intensity threshold determined in S112. Figure 17 , indicating the strength of the beacon signal. In this reference example, the front UWB anchor point 78 has a shield 88 (refer to Figure 6 ). Therefore, if Figure 17 As shown, the first antenna 82 and the second antenna 84 of the front UWB anchor point 78 cannot receive most of the beacon signal transmitted from the rear side of the front UWB anchor point 78 ( Figure 17 However, the beacon signal from the rear side of the front UWB anchor point 78 may sometimes go around the front side of the front UWB anchor point 78 and reach the first antenna 82 and the second antenna 84 ( Figure 17 (Solid arrow). The beacon signal's radio wave strength weakens as it travels around the front side of the front UWB anchor point 78. Therefore, the radio wave strength of the beacon signal that travels from the rear side of the front UWB anchor point 78 to the front side of the front UWB anchor point 78 and reaches the first antenna 82 and the second antenna 84 is weaker than the radio wave strength of the beacon signal that travels from the front side of the front UWB anchor point 78 to reach the first antenna 82 and the second antenna 84.

[0199] return Figure 16If the radio wave intensity exceeds the radio wave intensity threshold, the main control unit 60 determines that the UWB tag 200 is in the follow-up driving permission area (YES in S120), and the process proceeds to S122. On the other hand, if the radio wave intensity is below the radio wave intensity threshold, the main control unit 60 determines that the UWB tag 200 is in the follow-up driving prohibition area (NO in S120), and the process proceeds to S140.

[0200] If the main control unit 60 receives no reception information from the front UWB anchor point 78 in S110, it determines that the UWB tag 200 is in the following driving prohibited area (NO in S120), and the process proceeds to S140. If no reception information is received, it is likely that the UWB tag 200 is located further back than the front UWB anchor point 78.

[0201] In S122, the main control unit 60 calculates the temporary target speed TTV and the target angular speed Tω using the first distance D1 and the first angle a1 in such a manner that the transport vehicle 2 tracks the UWB tag 200. Specifically, the main control unit 60 calculates the temporary target speed TTV using the first distance D1 and the following equation (2), and calculates the target angular speed Tω using the first angle a1 and the following equation (3). "Vg1" and "Vo1" in equation (2) are the first speed gain and the first speed offset, respectively. The first speed offset Vo1 is a value used to stop the transport vehicle 302 in front of the user. "ωg1" in equation (3) is the first angular speed gain.

[0202] (Formula 2)

[0203] TTV=(D1×Vg1)-Vo1···(2)

[0204] (Formula 3)

[0205] Tω=a1×ωg1···(3)

[0206] In S124, the main control unit 60 calculates the speed limit VL using the first angle a1. Specifically, the main control unit 60 calculates the speed limit VL using the following equation (4). "Vmax" and "Vo2" in equation (4) represent the maximum speed of the transport vehicle 302 and the second speed offset. The second speed offset Vo2 is a value determined by the first angle a1. The larger the first angle a1, the larger the second speed offset Vo2. In other words, the larger the first angle a1, the smaller the speed limit VL.

[0207] (Formula 4)

[0208] VL=Vmax-Vo2···(4)

[0209] In S126, the main control unit 60 determines whether the temporary target speed TTV exceeds the speed limit VL. If the main control unit 60 determines that the temporary target speed TTV exceeds the speed limit VL (YES in S126), the process proceeds to S128. On the other hand, if the main control unit 60 determines that the temporary target speed TTV does not exceed the speed limit VL (NO in S126), the process proceeds to S130.

[0210] In S128 , the main control unit 60 determines the speed limit VL as the target speed TV.

[0211] Furthermore, in S130 , the main control unit 60 determines the temporary target speed TTV as the target speed TV.

[0212] In S132, the main control unit 60 controls the operation of the transport vehicle 302. Specifically, based on the target velocity TV and the target angular velocity Tω, the main control unit 60 controls the operation of the right front wheel motor 140A, the left front wheel motor 140B, the right rear wheel motor 140C, the left rear wheel motor 140D, and the steering motor 134. When S132 ends, the process returns to S110.

[0213] Furthermore, in S140, the main control unit 60 determines the target velocity TV and the target angular velocity Tω of the transport vehicle 302 to be zero. When S140 is completed, the process proceeds to S132.

[0214] In S132 after S140 , the main control unit 60 prohibits the transport vehicle 302 from traveling.

[0215] As described above, the main control unit 60 can accurately determine whether the UWB tag 200 is in the follow-up driving permission area by using the radio wave intensity and the radio wave intensity threshold. Therefore, if the UWB tag 200 is in the follow-up driving prohibition area, follow-up driving can be suppressed.

[0216] The features of the transport vehicle 302 disclosed in this reference example are as follows.

[0217] (Feature 2-1)

[0218] A transport vehicle includes: a vehicle body unit, a grounding portion supported by the vehicle body unit and in contact with the ground, a power machine for driving the grounding portion, a UWB anchor point for receiving a beacon signal from a UWB tag carried by a user, and a control unit.

[0219] The reception sensitivity for signals from the front side of the UWB anchor point is greater than the reception sensitivity for signals from the rear side of the UWB anchor point.

[0220] The control unit determines whether the UWB tag is located forward of the UWB anchor point using the radio wave strength of the beacon signal received from the UWB tag.

[0221] (Feature 2-2)

[0222] In the transport vehicle according to feature 2-1, the UWB anchor point includes: a first antenna and a second antenna different from the first antenna;

[0223] The control unit calculates a distance between the UWB anchor point and the UWB tag and an angle of the UWB tag relative to the UWB anchor point by using the beacon signal received by the first antenna and the beacon signal received by the second antenna.

[0224] (Features 2-3)

[0225] Based on the transport vehicle described in feature 2-1 or 2-2, the control unit determines that the UWB tag is located forward of the UWB anchor point when the radio wave intensity exceeds the radio wave intensity threshold, and determines that the UWB tag is located backward of the UWB anchor point when the radio wave intensity is below the radio wave intensity threshold.

[0226] (Features 2-4)

[0227] In the transport vehicle described in feature 2-3, the control unit calculates the distance between the UWB tag and the UWB anchor point using the beacon signal received by the UWB anchor point.

[0228] The longer the distance, the smaller the radio wave intensity threshold.

[0229] (Features 2-5)

[0230] In the transport vehicle according to any one of features 2-1 to 2-4, the transport vehicle includes: a cargo platform supported by the vehicle body unit;

[0231] The UWB anchor point is arranged at a position forward of the shelf.

[0232] (Features 2-6)

[0233] In the transport vehicle according to any one of features 2-1 to 2-5, the transport vehicle includes only one UWB anchor point.

[0234] (Features 2-7)

[0235] Based on the transport vehicle described in any one of features 2-1 to 2-6, the control unit determines that the UWB tag is in a following driving permission area in which movement by tracking the UWB tag is permitted when the UWB tag is determined to be in a position forward of the UWB anchor point; determines that the UWB tag is in a following driving prohibited area in which movement by tracking the UWB tag is prohibited when the UWB tag is determined to be in a position rearward of the UWB anchor point; and stops the operation of the power machine when it is determined that the UWB tag has moved from the following driving permission area to the following driving prohibited area.

[0236] The effects of the above-mentioned features 2-1 to 2-7 will be described.

[0237] In one or more embodiments, a transport vehicle 302 includes: a vehicle body unit 4; wheels 10 (an example of a "grounding portion") supported by the vehicle body unit 4 and in contact with the ground; a travel motor 140 (an example of a "power unit") that drives the wheels 10; a front UWB anchor point 78 (an example of a "UWB anchor point") that receives a beacon signal from a UWB tag 200 carried by a user; and a control unit. The reception sensitivity for signals from the front side of the front UWB anchor point 78 is greater than the reception sensitivity for signals from the rear side of the front UWB anchor point 78. The control unit uses the radio wave strength of the beacon signal received from the UWB tag 200 to determine whether the UWB tag 200 is located forward of the front UWB anchor point 78.

[0238] According to the above configuration, it is possible to determine whether the UWB tag 200 , that is, the user, is located forward of the front UWB anchor point 78 using the radio wave intensity.

[0239] In one or more embodiments, the front UWB anchor point 78 includes a first antenna 82 and a second antenna 84. The control unit calculates a first distance D1 between the front UWB anchor point 78 and the UWB tag 200 and a first angle a1 of the UWB tag 200 relative to the front UWB anchor point 78 using the beacon signal received by the first antenna 82 and the beacon signal received by the second antenna 84.

[0240] According to the above configuration, the user's position can be grasped more accurately.

[0241] In one or more embodiments, the control unit determines that the UWB tag 200 is located forward of the front UWB anchor point 78 when the radio wave intensity exceeds the radio wave intensity threshold, and determines that the UWB tag 200 is located backward of the front UWB anchor point 78 when the radio wave intensity is below the radio wave intensity threshold.

[0242] According to the above configuration, it is possible to more accurately grasp whether the user is located forward of the front UWB anchor point 78 .

[0243] In one or more embodiments, the control unit calculates the first distance D1 between the UWB tag 200 and the front UWB anchor point 78 using the beacon signal received by the front UWB anchor point 78 . The longer the first distance D1 is, the smaller the radio wave strength threshold is.

[0244] The longer the distance between the UWB tag 200 and the front UWB anchor point 78, the lower the radio wave intensity. Therefore, as the first distance D1 increases, the radio wave intensity threshold decreases. This allows the user to determine whether they are located forward of the front UWB anchor point 78, regardless of the distance between the UWB tag 200 and the front UWB anchor point 78.

[0245] In one or more embodiments, the transport vehicle 302 includes a cargo platform 6 supported by the vehicle body unit 4 . The front UWB anchor point 78 is disposed forward of the cargo platform 6 .

[0246] When goods are placed on the shelf 6, and the UWB tag is located in front of the transport vehicle 2 and the front UWB anchor point 78 is located further back than the shelf 6, the beacon signal from the UWB tag 200 may be blocked by the goods placed on the shelf 6, resulting in the front UWB anchor point 78 being unable to receive the beacon signal. According to the above configuration, the beacon signal from the UWB tag 200 is not blocked by the goods placed on the shelf 6, thereby increasing the probability of the front UWB anchor point 78 receiving the beacon signal. Furthermore, since the reception sensitivity of the front side of the front UWB anchor point 78 is higher than that of the rear side, the radio wave intensity can be used to accurately determine whether the user is located further forward than the front UWB anchor point 78.

[0247] In one or more embodiments, the transport vehicle 302 includes only one front UWB anchor point 78 .

[0248] According to the above configuration, the configuration of the transport vehicle 302 can be simplified compared to a configuration in which two or more UWB anchor points are used to determine whether the user is located forward of the front UWB anchor point 78 .

[0249] In one or more embodiments, the control unit determines that the UWB tag 200 is in a following driving allowed area where movement by tracking the UWB tag 200 is permitted when the UWB tag 200 is determined to be located forward of the front UWB anchor point 78; determines that the UWB tag 200 is in a following driving prohibited area where movement by tracking the UWB tag 200 is prohibited when the UWB tag 200 is determined to be located rearward of the front UWB anchor point 78; and stops the operation of the driving motor 140 when it is determined that the UWB tag 200 has moved from the following driving allowed area to the following driving prohibited area.

[0250] According to the above configuration, when the user is in the follow-up driving prohibited area, the guided vehicle 302 can be prevented from traveling. Therefore, the guided vehicle 302 can be caused to appropriately perform the follow-up driving.

[0251] (Variation 2-1) The transport vehicle 302 of Reference Example 1 may also have two or more UWB anchor points. In this case, at least one of the two or more UWB anchor points may have two antennas. Specifically, the UWB anchor point used to detect radio wave intensity may be different from the UWB anchor point used to detect the distance to the tag, etc.

[0252] (Variation 2-2) The radio wave intensity threshold may be constant regardless of the distance between the UWB tag 200 and the front UWB anchor point 78 .

[0253] (Variation 2-3) The front UWB anchor point 78 of Reference Example 1 may be arranged at a position further rearward than the shelf 6 .

[0254] (Variation 2-4) The control unit may determine that the UWB tag 200 is in a forward following area in which the transport vehicle 302 moves forward to track the UWB tag 200 when it is determined that the UWB tag 200 is in a forward following area in which the following driving is performed when the transport vehicle 302 moves forward to track the UWB tag 200, and may determine that the UWB tag 200 is in a backward driving area in which the transport vehicle 302 moves backward to track the UWB tag 200 when it is determined that the UWB tag 200 is in a backward driving area in which the following driving is performed when the transport vehicle 302 moves backward to track the UWB tag 200.

[0255] (Variation 2-5) The control unit may also determine that the UWB tag 200 is in the front lighting area where the right headlight 73A and the left headlight 73B are turned on when it is determined that the UWB tag 200 is in a position closer to the front than the front UWB anchor point 78, and determine that the UWB tag 200 is in the rear lighting area where the taillight 101 is turned on when it is determined that the UWB tag 200 is in a position closer to the rear than the front UWB anchor point 78.

[0256] (Reference Example 2) Figures 18 to 21 , explaining the transport vehicle 402 of reference example 2. Hereinafter, the differences between the transport vehicle 402 of reference example 2 and the transport vehicle 2 of embodiment 1 will be mainly explained, and the explanation of the common points will be omitted.

[0257] like Figure 18 As shown, the transport vehicle 402 of Reference Example 2 is different from the transport vehicle 2 of Example 1 in that the front UWB anchor point 78 (reference Figure 7 ) and the rear UWB anchor point 108 (refer to Figure 10 ), and has a right front UWB anchor point 412 and a left front UWB anchor point 410. In addition, the main control unit 60 of the reference example 2 (refer to Figure 5 ) can be replaced Figure 12 Follow-up mode processing is executed Figure 19 Follow-up mode processing.

[0258] Figure 18 The left front UWB anchor point 410 and the right front UWB anchor point 412 have the same characteristics as the front UWB anchor point 78 of Example 1 (see Figure 6 、 Figure 7 ) The left front UWB anchor point 410 and the right front UWB anchor point 412 are arranged on the housing 72 of the transport vehicle 402 (see Figure 1 That is, the left front UWB anchor point 410 and the right front UWB anchor point 412 are arranged on the shelf 6 (refer to Figure 1 ) is positioned forward. Left front UWB anchor point 410 is positioned to the left of the left-right center of transport vehicle 402. Right front UWB anchor point 412 is positioned to the right of the left-right center of transport vehicle 402. In the left-right direction, the midpoint between the two antennas of left front UWB anchor point 410 and the midpoint between the two antennas of right front UWB anchor point 412 are positioned at equal intervals from the center of transport vehicle 2.

[0259] (Follow-up mode processing; Figure 19 )Reference Figure 19 , explaining the following mode processing executed by the main control unit 60. When the operation mode of the transport vehicle 402 is set to the following mode, the main control unit 60 starts Figure 19 processing.

[0260] like Figure 20As shown, when the left front UWB anchor point 410 receives a beacon signal from the UWB tag 200, the distance from the left front UWB anchor point 410 to the UWB tag 200 (hereinafter referred to as "fourth distance D4") is calculated. Furthermore, when the right front UWB anchor point 412 receives a beacon signal from the UWB tag 200, the distance from the right front UWB anchor point 412 to the UWB tag 200 (hereinafter referred to as "fifth distance D5") is calculated. The calculation methods for the fourth distance D4 and the fifth distance D5 are the same as the calculation method for the first distance D1 in Example 1.

[0261] exist Figure 19 In S210, the main control unit 60 obtains the fourth distance D4 from the left front UWB anchor point 410. Specifically, in response to providing the third acquisition instruction for obtaining the fourth distance D4 to the left front UWB anchor point 410, the main control unit 60 obtains the fourth distance D4 from the left front UWB anchor point 410. Furthermore, if the left front UWB anchor point 410 does not receive a beacon signal from the UWB tag 200, the main control unit 60 obtains non-reception information from the left front UWB anchor point 410 indicating that the beacon signal was not received.

[0262] In S212, the main control unit 60 obtains the fifth distance D5 from the right front UWB anchor point 412. Specifically, in response to providing the fourth acquisition instruction for obtaining the fifth distance D5 to the right front UWB anchor point 412, the main control unit 60 obtains the fifth distance D5 from the right front UWB anchor point 412. Furthermore, if the right front UWB anchor point 412 does not receive a beacon signal from the UWB tag 200, the main control unit 60 obtains non-reception information from the right front UWB anchor point 412 indicating that the beacon signal was not received.

[0263] In S214, the main control unit 60 determines whether the UWB tag 200 is in the following driving permitted area. Specifically, the main control unit 60 determines whether non-reception information has been obtained from at least one of the left front UWB anchor point 410 and the right front UWB anchor point 412. If the main control unit 60 determines that non-reception information has not been obtained, it determines that the UWB tag 200 is located forward of the left front UWB anchor point 410 and the right front UWB anchor point 412. In this case, the main control unit 60 determines that the UWB tag 200 is in the following driving permitted area (YES in S214), and the process proceeds to S220. On the other hand, if the main control unit 60 determines that non-reception information has been obtained, it determines that the UWB tag 200 is located backward of the left front UWB anchor point 410 and the right front UWB anchor point 412. In this case, the main control unit 60 determines that the UWB tag 200 is in the following driving prohibited area (YES in S214 ), and the process proceeds to S216 .

[0264] In S216, the main control unit 60 determines the target velocity TV and target angular velocity Tω of the transport vehicle 402 to be zero, and stops the transport vehicle 302. When S216 is completed, the process returns to S210.

[0265] Furthermore, in S220, the main control unit 60 determines whether the fourth distance D4 and the fifth distance D5 are consistent. If the main control unit 60 determines that the fourth distance D4 and the fifth distance D5 are consistent (YES in S220), the process proceeds to S222. The fourth distance D4 and the fifth distance D5 being consistent means that the UWB tag 200 is located in front of the transport vehicle 402. On the other hand, if the main control unit 60 determines that the fourth distance D4 and the fifth distance D5 are inconsistent (NO in S220), the process proceeds to S230.

[0266] In S222, the main control unit 60 calculates the target speed TV of the transport vehicle 402. Specifically, the main control unit 60 calculates the target speed TV using the fourth distance D4, the fifth distance D5, and the following equation (5). "DA" and "Vg2" in equation (5) are the average of the fourth distance D4 and the fifth distance D5, and the second speed gain, respectively.

[0267] (Formula 5)

[0268] TV=DA×Vg2···(5)

[0269] In S224, the main control unit 60 causes the transport vehicle 402 to move straight using the target speed TV. When S224 is completed, the process returns to S210.

[0270] In addition, in S230, the main control unit 60 determines whether the fourth distance D4 is greater than the fifth distance D5. If the main control unit 60 determines that the fourth distance D4 is greater than the fifth distance D5 (YES in S230), the process proceeds to S232. In addition, the case where the fourth distance D4 is greater than the fifth distance D5 means: Figure 20 As shown in FIG. 4 , the UWB tag 200 is located to the right of the center position of the transport vehicle 402 in the left-right direction. On the other hand, if the main control unit 60 determines that the fourth distance D4 is not greater than the fifth distance D5 (NO in S230), the process proceeds to S240. In addition, the case where the fourth distance D4 is not greater than the fifth distance D5 means: Figure 21 As shown, the UWB tag 200 is located to the left of the center position of the transport vehicle 402 in the left-right direction.

[0271] like Figure 19As shown, in S232, the main control unit 60 calculates the target velocity TV and target angular velocity Tω of the transport vehicle 402 so that the transport vehicle 402 can track the UWB tag 200. The method for calculating the target velocity TV in this step is the same as the method for calculating the target velocity TV in S222. The main control unit 60 calculates the target angular velocity Tω using the fourth distance D4, the fifth distance D5, and the following equation (6). "ωg2" in equation (6) is the second angular velocity gain.

[0272] (Formula 6)

[0273] Tω=|D4-D5|×ωg2···(6)

[0274] In S234, the main control unit 60 turns the transport vehicle 402 to the right using the target velocity TV and the target angular velocity Tω. When S234 is completed, the process returns to S210.

[0275] In S240, the main control unit 60 calculates the target velocity TV and target angular velocity Tω of the transport vehicle 402 so that the transport vehicle 402 can track the UWB tag 200. The target velocity TV is calculated in this step using the same method as that used in S222. The target angular velocity Tω is calculated in this step using the same method as that used in S232.

[0276] In S242, the main control unit 60 turns the transport vehicle 402 to the left using the target velocity TV and the target angular velocity Tω. When S242 is completed, the process returns to S210.

[0277] As described above, the main control unit 60 can accurately determine whether the UWB tag 200 is located on the left or right side relative to the left-right center position of the transport vehicle 402 by using the fourth distance D4 and the fifth distance D5.

[0278] The features of the transport vehicle 402 disclosed in this reference example are as follows.

[0279] (Feature 3-1)

[0280] A transport vehicle comprises: a vehicle body unit, a grounding portion supported by the vehicle body unit and in contact with the ground, a power machine for driving the grounding portion, a first UWB anchor point for receiving a beacon signal from a UWB tag carried by a user, a second UWB anchor point located to the left of the first UWB anchor point and receiving the beacon signal, and a control unit for driving the power machine to perform a following driving operation in which the vehicle follows the UWB tag.

[0281] The control unit calculates a first tag distance between the first UWB anchor point and the UWB tag using the beacon signal received by the first UWB anchor point.

[0282] calculating a second tag distance between the second UWB anchor point and the UWB tag using the beacon signal received by the second UWB anchor point,

[0283] Based on the first tag distance and the second tag distance, it is determined whether the UWB tag is located to the right of the transport vehicle or to the left of the transport vehicle.

[0284] (Feature 3-2)

[0285] In the transport vehicle according to feature 3-1, the control unit determines the target angular velocity of the transport vehicle based on an absolute value of a difference between the first tag distance and the second tag distance.

[0286] (Feature 3-3)

[0287] In the transport vehicle according to feature 3-1 or 3-2, the control unit determines the target speed of the transport vehicle based on an average value of the first tag distance and the second tag distance.

[0288] The effects of the above-mentioned features 3-1 to 3-3 will be described.

[0289] In one or more embodiments, the transport vehicle 402 includes: a body unit 4; wheels 10 (an example of a "grounding portion"), which are supported by the body unit 4 and in contact with the ground; a driving motor 140 (an example of a "power machine"), which drives the wheels 10; a right front UWB anchor point 412 (an example of a "first UWB anchor point"), which receives a beacon signal from a UWB tag 200 carried by a user; a left front UWB anchor point 410 (an example of a "second UWB anchor point"), which is arranged at a position to the left of the right front UWB anchor point 412 and receives a beacon signal; and a control unit, which drives the driving motor 140 and is capable of performing follow-up driving to move following the UWB tag 200. The control unit uses the beacon signal received by the right front UWB anchor point 412 to calculate the fourth distance D4 between the right front UWB anchor point 412 and the UWB tag 200 (an example of the "first tag distance"), and uses the beacon signal received by the left front UWB anchor point 410 to calculate the fifth distance D5 between the left front UWB anchor point 410 and the UWB tag 200 (an example of the "second tag distance"), and based on the fourth distance D4 and the fifth distance D5, determines whether the UWB tag 200 is located to the right of the transport truck 402 or to the left of the transport truck 402.

[0290] According to the above configuration, by using the right front UWB anchor point 412 and the left front UWB anchor point 410 that are different in the left-right direction, the left-right position of the UWB tag 200 , ie, the left-right position of the user, can be appropriately determined.

[0291] In one or more embodiments, the control unit determines the target angular velocity Tω of the transport vehicle based on the absolute value of the difference between the fourth distance D4 and the fifth distance D5.

[0292] According to the above configuration, the angular velocity of the transport vehicle 402 can be adjusted according to the distance between the transport vehicle 402 and the user.

[0293] In one or more embodiments, the control unit determines the target speed TV of the transport vehicle 402 based on an average value of the fourth distance D4 and the fifth distance D5.

[0294] According to the above configuration, the speed of the transport vehicle 402 can be adjusted according to the distance between the transport vehicle 402 and the user.

[0295] (Variation 3-1) At least one of the right front UWB anchor point 412 and the left front UWB anchor point 410 may have only one antenna.

[0296] (Variation 3-2) The front-right UWB anchor point 412 and the front-left UWB anchor point 410 may have different positions in the front-rear direction.

[0297] (3-3rd Modification) The right front UWB anchor point 412 and the left front UWB anchor point 410 may be arranged at a position further rearward than the shelf 6 .

[0298] (3-4 variant) Figure 19 In S222, the main control unit 60 may calculate the target speed TV using one of the fourth distance D4 and the fifth distance D5. Furthermore, in S232 and S240, the main control unit 60 may calculate the target speed TV and the target angular velocity Tω using one of the fourth distance D4 and the fifth distance D5.

[0299] (Example 2: Transport system 501) Figure 22 - Figure 25 As shown, the transport system 501 includes a transport vehicle 502 and a beacon 582 .

[0300] (Configuration of Transport Vehicle 502) Figure 22The transporter 502 shown in FIG. 5 includes a vehicle body 504, a cargo platform 506, a handlebar 508, a right front wheel 510, a left front wheel 512, a right rear wheel 514, and a left rear wheel 516. The cargo platform 506, the handlebar 508, the right front wheel 510, the left front wheel 512, the right rear wheel 514, and the left rear wheel 516 are all supported by the vehicle body 504. The transporter 502 transports the cargo placed on the cargo platform 506. The transporter 502 includes a communication module 518 (see FIG. 5 ) mounted on the vehicle body 504. Figure 23 The transport vehicle 502 can operate in any of the following modes: manual mode, following mode, or parking mode. In manual mode, the transport vehicle 502 moves forward or backward according to the user's operation when the user standing behind the vehicle body 504 holds the handlebars 508 with both hands. In following mode, the transport vehicle 502: tracks the beacon 582 carried by the user standing in front of the vehicle body 504 (see Figure 24 In this case, the transport vehicle 502 communicates with the beacon 582 via the communication module 518. In parking mode, the transport vehicle 502 does not accept any instructions from the handlebars 508 or the beacon 582, but remains parked.

[0301] The transport vehicle 502 includes a battery mounting portion 520 provided on a vehicle body 504. A battery pack 522 (see Figure 23 ) is attachable and detachable to the battery mounting portion 520. The battery pack 522 includes secondary battery cells (not shown), such as lithium-ion battery cells, and is rechargeable using a charger (not shown). The transport vehicle 502 operates on power supplied by the battery pack 522 mounted on the battery mounting portion 520.

[0302] like Figure 23 As shown, transport vehicle 502 includes a right front wheel motor 524 that drives right front wheel 510, a left front wheel motor 526 that drives left front wheel 512, a right rear wheel motor 528 that drives right rear wheel 514, and a left rear wheel motor 530 that drives left rear wheel 516. Right front wheel motor 524, left front wheel motor 526, right rear wheel motor 528, and left rear wheel motor 530 are, for example, brushless motors. Right front wheel motor 524, left front wheel motor 526, right rear wheel motor 528, and left rear wheel motor 530 are supported by vehicle body 504.

[0303] like Figure 22 As shown, the handlebar 508 can be rotated around a rotation axis extending in the vertical direction relative to the vehicle body 504. The user can rotate the handlebar 508 while holding the handlebar 508 with both hands. Figure 23As shown, the transport vehicle 502 includes a handlebar angle sensor 532 that detects the rotation angle of the handlebar 508 as the handlebar angle, a steering mechanism 534 that steers the right front wheel 510 and the left front wheel 512 as steerable wheels, and a steering motor 536 that drives the steering mechanism 534. The steering motor 536 is, for example, a brushless motor. The handlebar angle sensor 532, the steering mechanism 534, and the steering motor 536 are supported by the vehicle body 504.

[0304] like Figure 22 As shown, switch boxes 538a and 538b are provided on the handlebar 508. Figure 23 As shown, switch boxes 538a and 538b are equipped with a main power switch 540, a mode switch 542, a trigger switch 544, a travel direction switch 546, and a speed switch 548. The main power switch 540 switches the main power of the transport vehicle 502 on and off. The mode switch 542 switches the operation mode of the transport vehicle 502 between manual mode, follow mode, and parking mode. The trigger switch 544 switches the travel of the transport vehicle 502 on and off and adjusts the travel speed of the transport vehicle 502 in manual mode. The travel direction switch 546 switches the travel direction of the transport vehicle 502 between forward and reverse in manual mode. The speed switch 548 switches the travel speed of the transport vehicle 502 between low and high speed in manual mode. While holding the handlebars 508 with both hands, the user can operate the main power switch 540 , the mode switch 542 , the trigger switch 544 , the travel direction switch 546 , and the speed switch 548 .

[0305] The transport vehicle 502 includes a control power circuit 550 and a control unit 552. When the main power switch 540 is turned on, the control power circuit 550 allows power to be supplied from the battery pack 522 to various components of the transport vehicle 502 (e.g., the control unit 552, the right front wheel motor 524, the left front wheel motor 526, the right rear wheel motor 528, the left rear wheel motor 530, the steering motor 536, etc.). When the main power switch 540 is turned off, the control power circuit 550 prohibits power from being supplied from the battery pack 522 to various components of the transport vehicle 502. The control power circuit 550 adjusts the power supplied from the battery pack 522 to a voltage suitable for each component of the transport vehicle 502 and outputs it to each component of the transport vehicle 502. The control unit 552 is composed of a CPU, ROM, RAM, etc. The CPU executes processing based on information stored in the ROM or RAM to control the operation of the transport vehicle 502. The control unit 552 controls the operation of the right front wheel motor 524, the left front wheel motor 526, the right rear wheel motor 528, the left rear wheel motor 530, and the steering motor 536 via motor drivers 554, 556, 558, 560, and 562. Furthermore, brake circuits 564, 566, 568, and 570 are connected to the motor drivers 554, 556, 558, and 560, corresponding to the right front wheel motor 524, the left front wheel motor 526, the right rear wheel motor 528, and the left rear wheel motor 530. The control unit 552 causes a large current to flow through the brake circuits 564, 566, 568, and 570 during the rotation of the right front wheel motor 524, the left front wheel motor 526, the right rear wheel motor 528, and the left rear wheel motor 530. This allows a large braking force to be applied to the right front wheel motor 524, the left front wheel motor 526, the right rear wheel motor 528, and the left rear wheel motor 530. The control power supply circuit 550, the control unit 552, the motor drivers 554, 556, 558, 560, and 562, and the brake circuits 564, 566, 568, and 570 are supported by the vehicle body 504.

[0306] (Configuration of Beacon 582) Figure 24The beacon 582 shown is a communication terminal configured to communicate with the transport vehicle 502. The beacon 582 includes a housing 584, a main power switch 586, an initialization switch 588, a pairing switch 590, a follow-up start switch 592, and a follow-up stop switch 594. The housing 584 has a generally rectangular parallelepiped shape. A clip 596 is provided on the rear surface of the housing 584. The clip 596 allows the beacon 582 to be attached to a user's body (e.g., a belt). Furthermore, a loop 598 is provided on the upper portion of the housing 584. The loop 598 allows the beacon 582 to be secured to a holder attached to the user's body (e.g., a safety hook). The main power switch 586 is located on the front surface of the housing 584, offset from the center toward the upper left. The initialization switch 588 is located on the front surface of the housing 584, offset from the center toward the lower right. The pairing switch 590 is located on the right surface of the housing 584. The follow-up start switch 592 and the follow-up stop switch 594 are provided in the center portion of the front surface of the housing 584. The follow-up start switch 592 is arranged above the follow-up stop switch 594. The surface of the follow-up start switch 592 has a protrusion 600, thereby having a concave and convex shape. For example, the protrusion 600 is composed of a plurality of ridges extending in the left-right direction. On the other hand, the surface of the follow-up stop switch 594 has a flat shape. Thus, the user can distinguish between the follow-up start switch 592 and the follow-up stop switch 594 by confirming the presence or absence of the protrusion 600. In addition, please note: Figure 24 The front-back direction, left-right direction and up-down direction shown in FIG. 5 are the same as the front-back direction, left-right direction and up-down direction based on the transport vehicle 502 (see FIG. Figure 22 )different.

[0307] like Figure 25 As shown, beacon 582 includes microcomputer 602, power IC 604, charging IC 606, battery protection IC 608, battery interface 610, and USB port 612. As will be described in detail later, beacon 582 operates with power supplied from battery 628 or USB port 612.

[0308] A first conductive line 614, a second conductive line 616, and a third conductive line 618 are provided between the microcomputer 602, the battery interface 610, and the USB port 612. One end of the first conductive line 614 is connected to the battery interface 610. One end of the second conductive line 616 is connected to the microcomputer 602. One end of the third conductive line 618 is connected to the USB port 612. The other ends of the first conductive line 614, the second conductive line 616, and the third conductive line 618 are connected to each other at a connection point 620.

[0309] On the first conductive path 614 , arranged in sequence from the battery interface 610 toward the connection point 620 , are: a fuse 622 , a battery protection switch circuit 624 , and a first charging switch circuit 626 of the charging IC 606 .

[0310] The battery 628 is installed in the battery interface 610. The battery 628 is, for example, a button-type rechargeable secondary battery (eg, a lithium-ion battery).

[0311] The battery protection switch circuit 624 of this embodiment is an N-channel MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor), and the direction from the drain to the source is: from the battery interface 610 to the connection point 620. Therefore, when the battery protection switch circuit 624 is on, it allows current to flow from the battery interface 610 to the connection point 620, and when it is off, it prohibits current from flowing from the battery interface 610 to the connection point 620. In addition, a parasitic diode is formed in the battery protection switch circuit 624. This parasitic diode allows current to flow from the source to the drain of the MOSFET. Therefore, in the battery protection switch circuit 624, regardless of whether the battery protection switch circuit 624 is on / off, current is allowed to flow from the connection point 620 to the battery interface 610.

[0312] The first charging switch circuit 626 of this embodiment is a P-channel MOSFET, and the direction from the source to the drain is: from the connection point 620 to the battery interface 610. Therefore, when the first charging switch circuit 626 is on, it allows current to flow from the connection point 620 to the battery interface 610. When it is off, it prohibits current from flowing from the connection point 620 to the battery interface 610. In addition, a parasitic diode is formed in the first charging switch circuit 626. This parasitic diode allows current to flow from the drain of the MOSFET to the source. Therefore, in the first charging switch circuit 626, regardless of whether the first charging switch circuit 626 is on or off, current is allowed to flow from the battery interface 610 to the connection point 620.

[0313] The battery protection IC 608 is configured to detect whether an abnormality has occurred in the battery 628 and, based on the detection result, toggle the battery protection switch circuit 624 and / or the first charging switch circuit 626 on and off. For example, if the temperature of the battery 628 becomes excessively high (e.g., above 60 degrees Celsius), the battery protection IC 608 switches the battery protection switch circuit 624 and the first charging switch circuit 626 off. This prohibits charging and discharging of the battery 628. Alternatively, if the battery 628 becomes over-discharged, the battery protection IC 608 switches the battery protection switch circuit 624 off. This prohibits discharging of the battery 628. Alternatively, if the battery 628 becomes over-charged, the battery protection IC 608 switches the first charging switch circuit 626 off. This prohibits charging of the battery 628. Although described in detail later, the battery protection IC 608 can also switch the first charging switch circuit 626 on and off based on a signal output from the microcomputer 602 .

[0314] On the second conductive path 616 , a regulator 630 of the power IC 604 and a power switch circuit 632 of the power IC 604 are provided in this order from the microcomputer 602 toward the connection point 620 .

[0315] The microcomputer 602 is composed of a CPU, ROM, RAM, etc. The microcomputer 602 controls the operation of the beacon 582 by executing processing based on the information stored in the ROM or RAM by the CPU. In addition, the microcomputer 602 includes a communication module 634 for communicating with the transport vehicle 502. The communication module 634 is configured to execute the communication module 518 (see FIG. 5 ) with the transport vehicle 502 when the pairing switch 590 is operated. Figure 23 ) between the transport vehicle 502 and the beacon 582. Communication modules 518 and 634 can also be pre-paired so that, when powered on, they automatically attempt to establish communication with their paired counterparts. Furthermore, communication modules 518 and 634 each comply with the UWB (UltraWide Band) standard. This enables communication (UWB communication) compliant with the UWB standard between the transport vehicle 502 and the beacon 582.

[0316] When supplied with power from the battery 628 or the USB port 612, the regulator 630 adjusts the supplied power to a predetermined control voltage (e.g., 3V) and outputs it to the microcomputer 602. The power adjusted to the control voltage is output to the microcomputer 602, enabling the microcomputer 602 to operate.

[0317] The power switch circuit 632 of this embodiment is a P-channel MOSFET. The direction from source to drain is from connection point 620 toward microcomputer 602. Therefore, when the power switch circuit 632 is on, it allows current to flow from connection point 620 to microcomputer 602. When it is off, it prohibits current from flowing from connection point 620 to microcomputer 602. Furthermore, a parasitic diode is formed in the power switch circuit 632. This parasitic diode allows current to flow from the drain to the source of the MOSFET. Therefore, in the power switch circuit 632, current is allowed to flow from microcomputer 602 to connection point 620 regardless of whether the power switch circuit 632 is on or off.

[0318] On the third conductive path 618 , a fuse 636 and a second charging switch circuit 638 of the charging IC 606 are provided in order from the USB port 612 toward the connection point 620 .

[0319] The second charge switch circuit 638 of this embodiment is an N-channel MOSFET. The direction from the drain to the source is from the USB port 612 to the connection point 620. Therefore, when the second charge switch circuit 638 is on, it allows current to flow from the USB port 612 to the connection point 620. When it is off, it prohibits current from flowing from the USB port 612 to the connection point 620. Furthermore, a parasitic diode is formed in the second charge switch circuit 638. This parasitic diode allows current to flow from the source to the drain of the MOSFET. Therefore, in the second charge switch circuit 638, current is allowed to flow from the connection point 620 to the USB port 612 regardless of whether the second charge switch circuit 638 is on or off.

[0320] Although not shown, the USB port 612 is provided on the housing 584 (see Figure 24) on the outer surface of the housing 612. A USB cable (not shown) can be connected to the USB port 612. Here, when a USB cable connected to an external power source (e.g., a commercial power source) is connected to the USB port 612, power is supplied from the external power source to the beacon 582 via the USB cable and the USB port 612. In this case, the beacon 582 is able to operate by the power supplied from the USB port 612. In this embodiment, the state of the beacon 582 that operates by the power supplied from the USB port 612 is referred to as the "external power operation state". When the beacon 582 is in the external power operation state, by supplying power from the external power source, a voltage is applied to the respective gates of the second charging switch circuit 638 and the power switch circuit 632, and the second charging switch circuit 638 and the power switch circuit 632 are respectively switched to ON. In this case, since power is allowed to be supplied from the USB port 612 to the microcomputer 602 via the third conductive line 618 and the second conductive line 616, power from the external power source is supplied to the microcomputer 602. This allows the microcomputer 602 to start up, and each unit of the beacon 582 (for example, the battery protection IC 608 ) to operate.

[0321] When beacon 582 is in the external power supply mode, microcomputer 602 switches the first charging switch circuit 626 on / off based on the remaining charge of battery 628 (i.e., the voltage of battery 628). For example, when the remaining charge of battery 628 is low, microcomputer 602 switches first charging switch circuit 626 on. Consequently, first charging switch circuit 626 and second charging switch circuit 638 are both on, allowing power to be supplied from USB port 612 via third conductive path 618 and first conductive path 614 to battery 628. As a result, power from the external power supply is supplied to battery 628, charging battery 628. When the remaining charge of battery 628 returns to a specified level, microcomputer 602 switches first charging switch circuit 626 off. This prevents power from being supplied from USB port 612 via third conductive path 618 and first conductive path 614 to battery 628, thereby terminating charging of battery 628. When beacon 582 is operating on external power, microcomputer 602 switches the power of communication module 634 on and off in response to operation of main power switch 586. In this case, while power switch circuit 632 remains on, power from the external power source continues to be supplied to microcomputer 602. In other words, the "main power" of beacon 582 referred to here refers to the power supplied to communication module 634. Furthermore, when beacon 582 is operating on external power, microcomputer 602 outputs a discharge enable signal to battery protection IC 608. In response to the discharge enable signal from microcomputer 602, battery protection IC 608 switches battery protection switch circuit 624 on, thereby allowing discharge from battery 628. If the USB cable is removed from USB port 612 while battery protection switch circuit 624 is on, and power to beacon 582 from the external power source is interrupted, beacon 582 operates on power supplied by battery 628. In this embodiment, the state of the beacon 582 at this time is referred to as the "internal power operation state".

[0322] When beacon 582 is in the internal power supply mode, the power switch circuit 632 is switched on / off in response to operation of the main power switch 586. This switches whether power from battery 628 to microcomputer 602 is permitted or prohibited, and accordingly, microcomputer 602 is switched on / off. Furthermore, when beacon 582 is in the internal power supply mode, microcomputer 602 outputs a discharge inhibit signal to battery protection IC 608 in response to operation of initialization switch 588. In response to the discharge inhibit signal output from microcomputer 602, battery protection IC 608 switches battery protection switch circuit 624 off. By turning off battery protection switch circuit 624, discharge from battery 628 is inhibited, and the operation of various components of beacon 582 (such as microcomputer 602) ceases. In this embodiment, the state of beacon 582 at this time is referred to as the "power-off state." After the beacon 582 is turned off, the battery protection switch circuit 624 is switched on to allow discharge from the battery 628. The USB cable needs to be connected to the USB port 612, and the microcomputer 602 is activated by supplying power from the external power supply.

[0323] (Example of Using Initialization Switch 588) After beacon 582 is manufactured, it may be stored in a warehouse as inventory for a long period of time (e.g., more than one year) until it is delivered to the user. Furthermore, after beacon 582 is delivered to the user, the user may not use it for a long time. During these periods, beacon 582 may be left unused without charging battery 628. In this case, battery 628 may discharge naturally, potentially causing it to become over-discharged. Regarding this, the beacon 582 of this embodiment can suppress natural discharge from battery 628 by pre-operating initialization switch 588 to turn off battery protection switch circuit 624. This prevents battery 628 from becoming over-discharged even if beacon 582 is left unused for a long period of time without charging the battery 628.

[0324] (Processing when the main power of beacon 582 is turned on: Figure 26 ) When the main power supply of the beacon 582 (i.e., the power supply of the communication module 634) is ON, the microcomputer 602 executes Figure 26 The processing shown.

[0325] In S302, the microcomputer 602 switches the beacon tracking flag to OFF. The beacon tracking flag referred to here is information stored in the microcomputer 602 and can take an arbitrary value of ON / OFF. After S302, the process proceeds to S304.

[0326] In S304, the microcomputer 602 transmits a beacon tracking flag to the transport vehicle 502. After S304, the process proceeds to S306.

[0327] In S306, the microcomputer 602 determines whether a response message has been received from the transport vehicle 502 within a first predetermined time (e.g., 50 milliseconds) after the start of S306. The transport vehicle 502 is configured to transmit a response message to the beacon 582 (see the following description) upon receiving the beacon following flag transmitted from the beacon 582. Figure 27 The response information includes: mode information indicating the operation mode of the transport vehicle 502, and a transport vehicle following flag. The transport vehicle following flag mentioned here is stored in the control unit 552 of the transport vehicle 502 (refer to Figure 23 ) and can take any value of ON / OFF. The transport vehicle following flag can also be referred to as information indicating whether the transport vehicle 502 is performing a following operation. If no response information is received even after the first predetermined time has passed after starting S306 (if NO), the process proceeds to S308.

[0328] In S308, the radio waves are disconnected between the transport vehicle 502 and the beacon 582, and accordingly, the microcomputer 602 determines that the communication between the transport vehicle 502 and the beacon 582 is not being properly performed. After S308, the process returns to S304.

[0329] If a response message is received within the first predetermined time after starting S306 (if S306 returns YES), the process proceeds to S310. In S310, the microcomputer 602 updates the beacon tracking flag using the transport vehicle tracking flag included in the response message received in S306. Specifically, if the transport vehicle tracking flag received in S306 indicates ON, the microcomputer 602 switches the beacon tracking flag to ON. If the transport vehicle tracking flag received in S306 indicates OFF, the microcomputer 602 switches the beacon tracking flag to OFF. After S310, the process proceeds to S312.

[0330] In S312, the microcomputer 602 determines whether the follow mode is selected by the guided vehicle 502 based on the mode information included in the response information received in S306. If the guided vehicle 502 has not selected the follow mode (NO), the process returns to S302. If the guided vehicle 502 has selected the follow mode (YES), the process proceeds to S314.

[0331] In S314, the microcomputer 602 determines whether the follow start switch 592 (see Figure 24 ) is operated. If the follow-up start switch 592 has been operated (in the case of YES), the process proceeds to S316.

[0332] In S316, the microcomputer 602 switches the beacon following flag to ON.

[0333] In the case where the follow start switch 592 is not operated in S314 (NO), or after S316, the process proceeds to S318. In S318, the microcomputer 602 determines whether the follow stop switch 594 (refer to Figure 24 ) has been operated. If the following stop switch 594 has been operated (in the case of YES), the process proceeds to S320.

[0334] In S320, the microcomputer 602 switches the beacon tracking flag to OFF.

[0335] In S322, the microcomputer 602 transmits a beacon tracking flag to the transport vehicle 502. After S322, the process proceeds to S324.

[0336] In S324, microcomputer 602 determines whether a response message has been received from transport vehicle 502 within the first predetermined time after S324 is initiated. The response message, as previously described, includes mode information indicating the operational mode of transport vehicle 502 and a transport vehicle following flag. If a response message has not been received even after the first predetermined time has elapsed after S324 is initiated (if the result is NO), processing proceeds to S308. If a response message has been received within the first predetermined time after S324 is initiated (if the result is YES), processing returns to S312.

[0337] (Processing when the main power of the transport vehicle 502 is turned on: Figure 27 ) When the main power supply of the transport vehicle 502 is on, the control unit 552 (see Figure 23 )implement Figure 27 The processing shown.

[0338] In S332, the control unit 552 switches the guided vehicle following flag to OFF. As previously described, the guided vehicle following flag is information stored in the control unit 552 and can take any value of ON / OFF. After S332, the process proceeds to S334.

[0339] In S334, if the following motion control process (refer to Figure 28 ) is being executed, the control unit 552 terminates the following motion control process. Details will be described later, but the following motion control process is the process that causes the transport vehicle 502 to perform a following motion. If the following motion control process is terminated but not executed, the transport vehicle 502 cannot perform the following motion. In other words, in S334, the following motion by the transport vehicle 502 is stopped. After S334, the process proceeds to S336.

[0340] In S336, the control unit 552 determines whether it has received the beacon following flag (see Figure 26 Even if the second predetermined time has passed after starting S336, if the beacon following flag has not been received (in the case of NO), the process proceeds to S338.

[0341] In S338, the control unit 552 determines that the communication between the transport vehicle 502 and the beacon 582 has been interrupted. After S338, the process returns to S332.

[0342] If the beacon tracking flag is received within the second predetermined time after starting S336 (if YES in S336), the process proceeds to S340. In S340, a response message is sent to beacon 582. As previously described, the response message includes mode information indicating the operating mode of transport vehicle 502 and the transport vehicle tracking flag. After S340, the process proceeds to S342.

[0343] In S342, it is determined whether the follow-up mode is selected for the transport vehicle 502. If the follow-up mode is not selected for the transport vehicle 502 (NO), the process returns to S332. If the follow-up mode is selected for the transport vehicle 502 (YES), the process proceeds to S344.

[0344] In S344, the control unit 552 determines whether the beacon tracking flag received in S336 is on. If the beacon tracking flag received in S336 is on (YES), the process proceeds to S346.

[0345] In S346, the control unit 552 switches the guided vehicle following flag to ON. After S346, the process proceeds to S348.

[0346] In S348, if the following motion control process (refer to Figure 28 ) is not being executed, the control unit 552 will start the follow-up motion control process. The details will be described later, but by executing the follow-up motion control process, the transport vehicle 502 can perform the follow-up motion. After S348, the process returns to S336.

[0347] If the beacon tracking flag received in S336 is OFF (NO in S344), the process proceeds to S350. In S350, the control unit 552 switches the transport vehicle tracking flag to OFF. After S350, the process proceeds to S352.

[0348] In S352, if the following motion control process (refer to Figure 28 ) is being executed, the control unit 552 terminates the following motion control process. As will be described in detail later, if the following motion control process is terminated but not executed, the transport vehicle 502 cannot perform the following motion. In other words, in S352, the following motion of the transport vehicle 502 is stopped. After S352, the process returns to S336.

[0349] (Regarding the follow-up start instruction / follow-up stop instruction sent from the beacon 582 to the transport vehicle 502) Figure 27 When the beacon following flag indicating ON is sent from beacon 582 to transport vehicle 502, the following operation of transport vehicle 502 is started. On the other hand, when the beacon following flag indicating OFF is sent from beacon 582 to transport vehicle 502, the following operation of transport vehicle 502 is stopped. Therefore, in this embodiment, the beacon following flag indicating ON is also referred to as a following start instruction sent from beacon 582 to transport vehicle 502. Furthermore, the beacon following flag indicating OFF is also referred to as a following stop instruction sent from beacon 582 to transport vehicle 502.

[0350] according to Figure 26 The process shown in FIG. 1 is to transmit a beacon following flag (following stop instruction) indicating OFF to the transport vehicle 502 immediately after the power of the beacon 582 is turned ON, regardless of the operation on the beacon 582 (see FIG. 1 ). Figure 26 Therefore, after the beacon 582 is powered on, the tracking start switch 592 (see Figure 24 ) is operated to transmit a beacon following flag indicating ON (following start instruction) to the transport vehicle 502. This can prevent the situation where the following operation of the transport vehicle 502 is started at a timing not intended by the user.

[0351] In addition, according to Figure 26 The process shown in FIG. 5 is to accept a call to the follow start switch 592 (see FIG. 5 ) while the communication between the transport vehicle 502 and the beacon 582 is established and the transport vehicle 502 is in the follow mode (the process from S312 to S324 is repeatedly executed). Figure 24 ) operation, and the follow-up stop switch 594 (refer to Figure 24) operation. Therefore, in this embodiment, the period during which communication between the transport vehicle 502 and the beacon 582 is established and the transport vehicle 502 is in the following mode is referred to as the "start operation acceptance period" or the "stop operation acceptance period." During the start operation acceptance period (stop operation acceptance period), if the following start switch 592 (following stop switch 594) is operated once, the beacon 582 will continue to send a following start instruction (following stop instruction) to the transport vehicle 502 until the following stop switch 594 (following start switch 592) is operated the next time. This prevents a situation in which the following operation of the transport vehicle 502 does not start (stop) at all, regardless of whether the user operates the following start switch 592 (following stop switch 594).

[0352] (Following motion control processing: Figure 28 ) The following motion control process is a process for controlling the following motion of the transport vehicle 502. Figure 27 Specifically, when the transport vehicle 502 receives the beacon following flag indicating ON (following start instruction) from the beacon 582, the following motion control process is started (refer to Figure 27 Furthermore, when the transport vehicle 502 receives the beacon following flag indicating OFF (following stop instruction) from the beacon 582, or when the communication between the transport vehicle 502 and the beacon 582 is interrupted, the following motion control process is terminated (refer to Figure 27 S344, S350, S352, S338, S332, S334).

[0353] exist Figure 28 In S372 shown, the control unit 552 determines the distance d to the beacon 582 and the offset angle θo of the beacon 582 using a positioning technology based on UWB communication such as ToA (Time of Arrival) or AoA (Angle of Arrival). Figure 29 As shown, the offset angle θo referred to herein is the offset angle relative to the forward direction FD of the transport vehicle 502. In this embodiment, when viewing the transport vehicle 502 from above, the clockwise direction 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 S372, the process proceeds to S374.

[0354] exist Figure 28 In S374 shown, the control unit 552 determines whether the offset angle θo determined in S372 is within the prescribed first angle range A1. Figure 29As shown, the first angle range A1 is defined as -θ1 ≤ θo ≤ θ1. The first boundary angle θ1, which defines the boundary of the first angle range A1, is, for example, in the range of 5 to 15 degrees. In this embodiment, it is 10 degrees. If the offset angle θo is within the first angle range A1 (YES), the process proceeds to S376.

[0355] exist Figure 28 In S376 shown, the control unit 552 determines the target angular velocity ω to be provided to the transport vehicle 502 based on the offset angle θo determined in S372. Figure 29 As shown in FIG. 1 , the target angular velocity ω referred to here is the angular velocity about an axis extending in the vertical direction. In this embodiment, the equation (7) for deriving the target angular velocity ω from the offset angle θo is determined as follows.

[0356] ω=ωK*θo···(7)

[0357] In addition, ωK in the formula (7) is a predetermined coefficient.

[0358] exist Figure 28 In S374 shown, if the offset angle θo is not within the first angle range A1 (NO), the process proceeds to S378. In S378, the control unit 552 determines whether the offset angle θo determined in S372 is within the specified second angle range A2. Figure 29 As shown, the second angular range A2 is adjacent to the first angular range A1 and is defined as -θ2 ≤ θo < -θ1, and θ1 < θo ≤ θ2. The second boundary angle θ2 is, for example, in the range of 15 to 30 degrees, and in this embodiment, is 30 degrees. If the offset angle θo is within the second angular range A2 (YES), the process proceeds to S380.

[0359] exist Figure 28 In S380, the control unit 552 determines the correction angle θa based on the offset angle θo determined in S372. The correction angle θa is determined so that θa < θo holds when the offset angle θo is positive, and so that θo < θa holds when the offset angle θo is negative. In this embodiment, the correction angle θa is determined to be θa = θ1 when the offset angle θo is positive, and to be θa = -θ1 when the offset angle θo is negative. After S380, the process proceeds to S382.

[0360] In S382, the control unit 552 determines the target angular velocity ω to be provided to the transport vehicle 502 based on the correction angle θa determined in S380. In this embodiment, the target angular velocity ω is determined by replacing the offset angle θo with the correction angle θa based on equation (7) used in S376 to obtain the following equation (8).

[0361] ω=ωK*θa···(8)

[0362] By determining the target angular velocity ω using equation (8), a target angular velocity ω having a smaller absolute value can be obtained compared to the case where the target angular velocity ω is determined using equation (7).

[0363] After S376 or S382, the process proceeds to S384. In S384, the control unit 552 determines the target straight-line speed V to be provided to the transport vehicle 502 based on the distance d to the beacon 582 determined in S372 and the offset angle θo. Figure 29 As shown, the target straight-line speed V referred to here is the straight-line speed in the forward direction FD of the transport vehicle 502. In this embodiment, the equation (9) for deriving the target straight-line speed V based on the distance d to the beacon 582 and the offset angle θo is determined as follows.

[0364] V=min(VK1*d-Vc1, Vc2-VK2*θo)···(9)

[0365] In addition, VK1 and VK2 in the formula (9) are predetermined coefficients, and Vc1 and Vc2 are constant terms.

[0366] exist Figure 28 In the S378 shown, when the offset angle θo is not within the second angle range A2 (case of NO), that is, when the offset angle θo is within the third angle range A3 defined as θo<-θ2, θ2<θo (refer to Figure 29 ), the process proceeds to S386. In S386, the control unit 552 determines the target angular velocity ω to be provided to the transport vehicle 502 to be ω=0, and further determines the target straight-line speed V to be provided to the transport vehicle 502 to be V=0.

[0367] After S384 or S386, the process proceeds to S388. In S388, the control unit 552 controls the transport vehicle 502 based on the determined target angular velocity ω and target straight-line speed V. Specifically, the control unit 552 controls the steering motor 536, the right front wheel motor 524, the left front wheel motor 526, the right rear wheel motor 528, and the left rear wheel motor 530 (see FIG. 1 ) so that the angular velocity and straight-line speed of the transport vehicle 502 are consistent with the target angular velocity ω and target straight-line speed V. Figure 23 ) is controlled. After S388, the process returns to S372.

[0368] In the following motion control process, the control unit 552 sets the offset angle θo to the third angle range A3 (see Figure 29 ) is determined as ω=0, V=0 (refer to Figure 28 In this case, the control unit 552 stops the right front wheel motor 524, the left front wheel motor 526, the right rear wheel motor 528, and the left rear wheel motor 530, thereby stopping the movement (following action) of the transport vehicle 502. In other words, when the offset angle θo is within the third angle range A3, the movement (following action) of the transport vehicle 502 is prohibited.

[0369] Figure 30 The solid line shows the relationship between the offset angle θo and the curvature K of the following motion of the transport vehicle 502 when the distance d from the transport vehicle 502 to the beacon 582 is constant. Figure 29 ), the target angular velocity ω of the transport vehicle 502 is determined according to the aforementioned equation (7) (refer to Figure 28 S374, S376). As a result, the greater the absolute value of the offset angle θo, the greater the turning curvature K. In this embodiment, the turning curvature K when the target angular velocity ω is determined based on equation (7) is referred to as "normal turning curvature K (1)". In addition, when the offset angle θo is in the second angle range A2 (refer to Figure 29 ), the target angular velocity ω of the transport vehicle 502 is determined according to the aforementioned equation (8) (refer to Figure 28 As a result, the curvature K is constant regardless of the value of the offset angle θo. In the second angle range A2, the curvature K when the target angular velocity ω is determined based on equation (8) is smaller than the normal curvature K (1) (refer to Figure 30 In this embodiment, the turning curvature K when the target angular velocity ω is determined based on equation (8) is referred to as "suppressed turning curvature K (2)".

[0370] The minimum turning radius of the transport vehicle 502 in the following mode is, for example, within the range of 4339 mm to 15535 mm. In this embodiment, it is 7012 mm. The minimum turning radius of the transport vehicle 502 in the following mode is also referred to as the turning radius when the turning curvature K is suppressed.

[0371] (Processing in Manual Mode of the Transport Cart 502) When the main power of the transport car 502 is on and the manual mode is selected, Figure 23 The control unit 552 shown controls the transport vehicle 502 based on user operations. Specifically, the control unit 552 determines a target angular velocity ω and a target straight-line speed V to be provided to the transport vehicle 502 based on the handlebar angle detected by the handlebar angle sensor 532, the amount of pull of the trigger switch 544, and the state of the transport vehicle 502's travel speed selected by the speed selector switch 548. The control unit 552 then controls the steering motor 536, the right front wheel motor 524, the left front wheel motor 526, the right rear wheel motor 528, and the left rear wheel motor 530 so that the angular velocity and straight-line speed of the transport vehicle 502 match the determined target angular velocity ω and target straight-line speed V. The minimum turning radius of the transport vehicle 502 in manual mode is smaller than that in follow mode; in this embodiment, it is 953 mm.

[0372] (Example 3: Transport system 701) The transport system 701 has: Figure 22 - Figure 30 The transport system 701 is different from the transport system 501 of Example 2 only in that: Figure 28 The processing shown in FIG. 5 is performed by the control unit 552 (see FIG. Figure 23 )implement Figure 31 In addition, Figure 31 The treatment shown is for Figure 28 The following is obtained by changing part of the processing shown in Figure 31 The processing shown only describes Figure 28 The processing shown is changed.

[0373] exist Figure 31 In the illustrated process, S400 is executed after S382. In S400, the control unit 552 determines the target straight-line speed V to be provided to the transport vehicle 502 based on the distance d to the beacon 582 determined in S372 and the correction angle θa determined in S380. In this embodiment, the target straight-line speed V is determined by replacing the offset angle θo with the correction angle θa based on equation (9) used in S384 to obtain the following equation (10).

[0374] V=min(VK1*d-Vc1, Vc2-VK2*θa)···(10)

[0375] After S400 , the process proceeds to S388 .

[0376] (Variation) The beacon 582 may be replaced with another communication terminal (eg, a smartphone or tablet).

[0377] The power machine driving the right front wheel 510, the left front wheel 512, the right rear wheel 514, and the left rear wheel 516 of the transport vehicle 502 may be replaced with a power machine other than an electric motor (for example, an engine including an internal combustion engine).

[0378] The transport vehicle 502 may not have a manual mode (or parking mode) in its operating mode. That is, the operating mode of the transport vehicle 502 may be switchable between a follow mode and a parking mode (or manual mode). Alternatively, the transport vehicle 502 may have only a follow mode. In this case, the transport vehicle 502 may not have the mode switch 542.

[0379] exist Figure 28 In S372, the control unit 552 may determine the distance d to the beacon 582 and the offset angle θo of the beacon 582 using a positioning technology other than the positioning technology based on UWB communication. For example, a positioning technology based on Bluetooth (registered trademark) communication or a positioning technology based on Wi-Fi (registered trademark) communication may be used.

[0380] exist Figure 28 In the processing of , instead of determining the target angular velocity ω to be provided to the transport vehicle 502, the control unit 552 may determine the target steering angle (the steering angle of the steering wheel relative to the forward direction FD) to be provided to the steering wheels (right front wheel 510 and left front wheel 512) of the transport vehicle 502. In this case, Figure 28 In S388, the control unit 552 may also control the steering motor 536, the right front wheel motor 524, the left front wheel motor 526, the right rear wheel motor 528 and the left rear wheel motor 530 in such a manner that the straight-ahead speed of the transport vehicle 502 is consistent with the target straight-ahead speed V on the basis of adjusting the steering angle of the steering wheel to the target steering angle.

[0381] The transport vehicle 502 may not have the steering mechanism 534. Even in this case, the transport vehicle 502 can perform a turning action by giving a difference between the rotation speeds of the right front wheel 510 and the right rear wheel 514 and the rotation speeds of the left front wheel 512 and the left rear wheel 516. Figure 28In S388, the control unit 552 of the transport vehicle 502 may also control the rotational speeds of the right front wheel 510, the left front wheel 512, the right rear wheel 514, and the left rear wheel 516 so that the angular velocity and the straight-line speed of the transport vehicle 502 are consistent with the target angular velocity ω and the target straight-line speed V.

[0382] exist Figure 28 In the process of , after NO in S374, the process may skip S378 and proceed to S380. That is, even if the offset angle θo is within the third angle range A3, the control unit 552 may continue the movement (following operation) of the transport vehicle 502 without stopping it.

[0383] The beacon 582 may not have the following stop switch 594 (see Figure 24 Even in this case, the user can operate the main power switch 586 (see Figure 24 ) and the main power supply of the beacon 582 is turned OFF, which can also indirectly stop the following action of the transport vehicle 502. This is because: when the main power supply of the beacon 582 is turned OFF, the communication between the transport vehicle 502 and the beacon 582 is interrupted. Figure 27 If the answer in S336 is NO, the transport vehicle 502 will stop the following action through the processing of the following S338, S332, and S334.

[0384] The conditions for ending the transmission of the start instruction for ending the transmission of the follow-up start instruction from the beacon 582 to the transport vehicle 502 may also include: turning on the follow-up stop switch 594 (see Figure 24 For example, the start instruction sending end condition may also include: when the follow start switch 592 (refer to Figure 24 Alternatively, the start instruction sending end condition may also include: the transport vehicle 502 has completed the follow-up action control processing (refer to Figure 28 ) such conditions.

[0385] The stop instruction transmission termination condition for terminating the transmission of the follow-up stop instruction from the beacon 582 to the transport vehicle 502 may also include: turning on the follow-up start switch 592 (see Figure 24 For example, the stop instruction sending end condition may also include: following the stop switch 594 (refer to Figure 24 Alternatively, the stop instruction sending end condition may also include: the transport vehicle 502 starts the follow-up action control process (refer to Figure 28 ) such conditions.

[0386] The start operation acceptance period (stop operation acceptance period) may also include the period when the transport vehicle 502 is in the manual mode (or parking mode). Accordingly, during the period when the transport vehicle 502 is in the manual mode (or parking mode), the follow start switch 592 (see Figure 24 ) and the operation of the follow-up stop switch 594 (refer to Figure 24 ) operations.

[0387] The start operation acceptance period (stop operation acceptance period) may also include a period during which communication between the transport vehicle 502 and the beacon 582 is not established. Accordingly, during the period during which communication between the transport vehicle 502 and the beacon 582 is not established, a call to the follow start switch 592 (see Figure 24 ) and the operation of the follow-up stop switch 594 (refer to Figure 24 ) operations.

[0388] exist Figure 26 That is, immediately after the beacon 582 is powered on, or when the transport vehicle 502 has not selected the follow mode (in the case of NO in S312), the beacon follow flag may not be switched to OFF.

[0389] Battery 628 (refer to Figure 25 ) can also be a primary battery that cannot be recharged (such as a manganese lithium battery). In this case, the battery 628 can also be detachable relative to the beacon 582.

[0390] The battery protection switch circuit 624, the power switch circuit 632, the first charging switch circuit 626, and the second charging switch circuit 638 (see Figure 25 ) can also be mechanical switches respectively.

[0391] The beacon 582 may further include: a battery protection switch circuit 624 (see Figure 25 ) is switched to an operating unit (switch, etc.) in the state of being turned ON. In this case, in order to switch the battery protection switch circuit 624 from OFF to ON, it is also necessary to operate the above-mentioned operating unit after the beacon 582 is in the external power supply operation state.

[0392] (Features of Embodiments 2 and 3) In one or more embodiments, the transport vehicle 502 is capable of performing a following operation to autonomously follow a beacon 582 (an example of a following target). The transport vehicle 502 includes a vehicle body 504, a right front wheel 510, a left front wheel 512, a right rear wheel 514, and a left rear wheel 516 (examples of wheels) supported by the vehicle body 504 and in contact with the ground, a right front wheel motor 524, a left front wheel motor 526, a right rear wheel motor 528, and a left rear wheel motor 530 (examples of a power machine) that drive the right front wheel 510, the left front wheel 512, the right rear wheel 514, and the left rear wheel 516, a communication module 518 that detects an offset angle θo of the beacon 582 relative to the forward direction FD of the transport vehicle 502, and a control unit 552 (examples of an offset angle detection unit). The control unit 552 is configured to execute a following motion control process for controlling the following motion of the transport vehicle 502. In the following motion control process, when the offset angle θo is within a first angular range A1 including 0 degrees, the control unit 552 adjusts the turning curvature K (an example of a turning degree) in the following motion of the transport vehicle 502 to a normal turning curvature K(1) corresponding to the offset angle θo. When the offset angle θo is within a second angular range A2 adjacent to the first angular range A1, the control unit 552 adjusts the turning curvature K in the following motion of the transport vehicle 502 to a suppressed turning curvature K(2) that is suppressed compared to the normal turning curvature K(1) corresponding to the offset angle θo.

[0393] Since a larger absolute value of the offset angle θo increases the turning angle required to align the guided vehicle 502's forward direction FD with the beacon 582, increasing the turning curvature K of the guided vehicle 502 may be considered. However, if the turning curvature K of the guided vehicle 502 is too large, the inner wheel differential of the guided vehicle 502 may be excessively increased. This may result in the guided vehicle 502 contacting an obstacle, preventing smooth following of the guided vehicle 502. According to the above configuration, when the offset angle θo is within the second angular range A2 (i.e., when the absolute value of the offset angle θo is relatively large), the turning curvature K of the guided vehicle 502 is suppressed compared to normal conditions. This prevents the turning curvature K of the guided vehicle 502 from being excessively large, thereby preventing the inner wheel differential of the guided vehicle 502 from being excessively increased. This prevents the guided vehicle 502 from contacting an obstacle, allowing smooth following of the guided vehicle 502.

[0394] In one or more embodiments, the turning degree includes a turning curvature K of the transport vehicle 502. In the following motion control process, the control unit 552 adjusts the turning curvature K of the transport vehicle 502 in the following motion to a normal turning curvature K(1) corresponding to the offset angle θo when the offset angle θo is within a first angular range A1, and adjusts the turning curvature K of the transport vehicle 502 in the following motion to a suppressed turning curvature K(2) that is lower than the normal turning curvature K(1) corresponding to the offset angle θo when the offset angle θo is within a second angular range A2.

[0395] According to the above configuration, when the offset angle θo is within the second angular range A2 (i.e., when the absolute value of the offset angle θo is relatively large), the turning curvature K of the guided vehicle 502 is reduced to a value lower than normal. This prevents the turning curvature K of the guided vehicle 502 from becoming excessively large, thereby preventing the inner wheel difference of the guided vehicle 502 from increasing excessively. This prevents the guided vehicle 502 from coming into contact with an obstacle, enabling smooth following of the guided vehicle 502.

[0396] In one or more embodiments, the transport vehicle 502 can switch between a following mode in which following is permitted and a manual mode in which following is prohibited and movement is based on user operation. The minimum turning radius of the transport vehicle 502 in the following mode is greater than the minimum turning radius of the transport vehicle 502 in the manual mode.

[0397] As the turning radius of the guided vehicle 502 decreases, the inner wheel difference of the guided vehicle 502 increases. Therefore, in the following mode (without user intervention), if the turning radius of the guided vehicle 502 decreases, the guided vehicle 502 may come into contact with an obstacle. On the other hand, in the manual mode (with user intervention), it is believed that even if the turning radius of the guided vehicle 502 decreases to a certain extent, the possibility of the guided vehicle 502 coming into contact with an obstacle is low. Conversely, if the turning radius of the guided vehicle 502 cannot be reduced in manual mode, the maneuverability of the guided vehicle 502 may be reduced. According to the above configuration, the minimum turning radius of the guided vehicle 502 in the following mode is larger than the minimum turning radius of the guided vehicle 502 in the manual mode. As a result, the reduction of the turning radius of the guided vehicle 502 in the following mode is suppressed, while the reduction of the turning radius in the manual mode is permitted. This prevents the maneuverability of the guided vehicle 502 in the manual mode from being compromised, and thus prevents the guided vehicle 502 from coming into contact with an obstacle in the following mode.

[0398] In one or more embodiments, in the following action control process, the control unit 552 stops the right front wheel motor 524, the left front wheel motor 526, the right rear wheel motor 528, and the left rear wheel motor 530 when the offset angle θo is within the third angle range A3 in addition to the first angle range A1 and the second angle range A2, thereby stopping the following action of the transport vehicle 502.

[0399] Since the larger the absolute value of the offset angle θo, the larger the turning angle required to align the forward direction FD of the transport vehicle 502 with the beacon 582, the transport vehicle 502 is forced to make a sharp turn. However, when the transport vehicle 502 makes a sharp turn, there is a possibility that the transport vehicle 502 may come into contact with an obstacle, preventing the transport vehicle 502 from following the vehicle smoothly. 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 transport vehicle 502's following action is stopped. This prevents the transport vehicle 502 from making a sharp turn. As a result, the transport vehicle 502 can be prevented from coming into contact with an obstacle, allowing the transport vehicle 502 to follow the vehicle smoothly.

[0400] In one or more embodiments, the transport vehicle 502 is capable of performing a following operation to autonomously follow a beacon 582 (an example of a following object). The transport vehicle 502 includes a vehicle body 504, a right front wheel 510, a left front wheel 512, a right rear wheel 514, and a left rear wheel 516 (examples of wheels) supported by the vehicle body 504 and in contact with the ground, a right front wheel motor 524, a left front wheel motor 526, a right rear wheel motor 528, and a left rear wheel motor 530 (examples of a power machine) that drive the right front wheel 510, the left front wheel 512, the right rear wheel 514, and the left rear wheel 516, a communication module 518 that detects an offset angle θo of the beacon 582 relative to the forward direction FD of the transport vehicle 502, and a control unit 552 (examples of an offset angle detection unit). When the offset angle θo is within the first angle range A1 and the second angle range A2 (an example of an action angle range) including 0 degrees, the control unit 552 operates the right front wheel motor 524, the left front wheel motor 526, the right rear wheel motor 528, and the left rear wheel motor 530, thereby causing the transport vehicle 502 to perform a following action. When the offset angle θo is within the third angle range A3 (an example of a stop angle range) adjacent to the first angle range A1 and the second angle range A2, the control unit 552 stops the right front wheel motor 524, the left front wheel motor 526, the right rear wheel motor 528, and the left rear wheel motor 530, thereby stopping the following action of the transport vehicle 502.

[0401] As the absolute value of the offset angle θo increases, the turning angle required to align the transport vehicle 502's forward direction FD with the beacon 582 increases, forcing the transport vehicle 502 to make a sharp turn. However, when making a sharp turn, the transport vehicle 502 may come into contact with an obstacle, preventing the transport vehicle 502 from following the beacon 582 smoothly. 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 transport vehicle 502's following action is executed. 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 transport vehicle 502's following action is stopped. This prevents the transport vehicle 502 from making a sharp turn. As a result, the transport vehicle 502 can be prevented from coming into contact with an obstacle, allowing the transport vehicle 502 to follow the beacon smoothly.

[0402] In one or more embodiments, the transport system 501, 701 includes: a transport vehicle 502, and a beacon 582 (an example of a communication terminal) configured to communicate with the transport vehicle 502. The transport vehicle 502 is configured to be able to perform a following action of following the beacon 582 when the beacon 582 moves. The beacon 582 includes: a main power switch 586 (an example of a first operating unit), and a following start switch 592 (an example of a second operating unit) provided at a position different from the main power switch 586. The beacon 582 switches the power ON / OFF when the main power switch 586 is operated. The beacon 582 is in a state where the power is turned ON and during a prescribed start operation acceptance period (from Figure 26 When the following start switch 592 is operated (during the period in which the processing from S312 to S324 is repeatedly executed), a following start instruction (a beacon following flag indicating ON) is sent to the transport vehicle 502 to instruct the start of the following action.

[0403] According to the above configuration, beacon 582 is provided with a follow-up start switch 592 for initiating the following operation of transport vehicle 502 at a position different from main power switch 586. Even if main power switch 586 is not operated in accordance with the user's will, the following operation of transport vehicle 502 will not be initiated unless follow-up start switch 592 is subsequently operated. This prevents the following operation of transport vehicle 502 from being initiated in accordance with the user's will.

[0404] In one or more embodiments, the beacon 582 further includes a follow-up stop switch 594 (an example of a third operating unit) provided at a position different from the main power switch 586 and the follow-up start switch 592. The beacon 582 is powered on and during a predetermined stop operation acceptance period ( Figure 26 If the following stop switch 594 is operated (during the period in which the processing from S312 to S324 is repeatedly executed), a following stop instruction (a beacon following flag indicating OFF) is sent to the transport vehicle 502 to instruct the transport vehicle 502 to stop the following action.

[0405] It is also possible to provide the beacon 582 with a switching operation unit for accepting the switch between starting and stopping the following action. However, according to this configuration, when the user operates the switching operation unit, it may be unclear to the user whether the beacon 582 indicates to the transport vehicle 502 whether to start or stop the following action. According to the above configuration, the operation unit for accepting the start of the following action (the following start switch 592) and the operation unit for accepting the stop of the following action (the following stop switch 594) are provided separately from each other. Accordingly, when the user operates the following start switch 592 / the following stop switch 594, it is clear to the user whether the beacon 582 indicates to the transport vehicle 502 whether to start or stop the following action.

[0406] In one or more embodiments, when the beacon 582 is powered on and the follow-up stop switch 594 is operated during the stop operation acceptance period, the beacon 582 continuously sends a follow-up stop instruction to the transport vehicle 502 until a predetermined transmission end condition is met.

[0407] For example, if communication between the transport vehicle 502 and the beacon 582 is poor, the following stop instruction sent by the beacon 582 may not be received by the transport vehicle 502. Regardless of whether the transport vehicle 502 receives the following stop instruction, once the beacon 582 stops sending the following stop instruction, the transport vehicle's following action will not be stopped and will continue to follow. With this configuration, it is possible that the following action of the transport vehicle 502 will not be stopped at all, regardless of whether the user operates the following stop switch 594. With the above configuration, the beacon 582 continues to send the following stop instruction after the following stop switch 594 is operated until the transmission end condition is met. This prevents the following action of the transport vehicle 502 from being stopped at all, regardless of whether the user operates the following stop switch 594.

[0408] In one or more embodiments, the transmission end condition includes a first transmission end condition in which the tracking start switch 592 is operated.

[0409] According to the above configuration, after the following stop switch 594 is operated, the beacon 582 continuously transmits the following stop instruction until the following start switch 592 is next operated. This prevents the following operation of the transport vehicle 502 from being completely stopped regardless of whether the user has operated the following stop switch 594.

[0410] In one or more embodiments, the transport vehicle 502 can switch between a follow mode that allows follow-up and a manual mode that prohibits follow-up and moves based on user operations. The start operation acceptance period is at least the period during which the transport vehicle 502 is in follow-up mode.

[0411] Assuming that the start operation acceptance period is while the transport vehicle 502 is in manual mode, if the follow start switch 592 is operated in manual mode, the transport vehicle 502's following operation may begin when the transport vehicle 502 subsequently switches to follow mode. Therefore, the start of the transport vehicle 502's following operation may be delayed for a while after the user operates the follow start switch 592. This could result in the transport vehicle 502's following operation starting at an unintended timing for the user. According to the above configuration, the start operation acceptance period is at least the period during which the transport vehicle 502 is in follow mode. Therefore, even if the follow start switch 592 is operated in manual mode, the operation is not accepted, and the transport vehicle 502's following operation will not subsequently begin. This prevents the transport vehicle 502's following operation from starting at an unintended timing.

[0412] In one or more embodiments, the start operation acceptance period is at least a period during which communication between the transport vehicle 502 and the beacon 582 is established.

[0413] Assuming that the period during which communication between the transport vehicle 502 and the beacon 582 is interrupted serves as the start operation acceptance period, if the follow start switch 592 is operated during this period, the transport vehicle 502's following operation may subsequently begin when communication is established. Therefore, the start of the transport vehicle 502's following operation may be delayed for a while after the user operates the follow start switch 592. This could result in the transport vehicle 502's following operation starting at an unintended timing for the user. According to the above configuration, the start operation acceptance period is at least the period during which communication between the transport vehicle 502 and the beacon 582 is established. Therefore, even if the follow start switch 592 is operated during the period during which communication between the transport vehicle 502 and the beacon 582 is interrupted, the operation will not be accepted, and the transport vehicle 502's following operation will not subsequently begin. This prevents the transport vehicle 502's following operation from starting at an unintended timing.

[0414] In one or more embodiments, the beacon 582 transmits a following stop instruction to the transport vehicle 502 to stop the following operation immediately after the power is turned on.

[0415] According to the above configuration, the following operation of the transport vehicle 502 is stopped immediately after the power of the beacon 582 is turned on. Therefore, after the power of the beacon 582 is turned on, the following operation of the transport vehicle 502 is started by operating the following start switch 592. This prevents the transport vehicle 502 from starting to follow the user regardless of the user's intention.

[0416] In one or more embodiments, the beacon 582 (an example of an electrical device) includes: a battery interface 610 that electrically connects the microcomputer 602 to the battery 628, a power switch circuit 632 (an example of a first switch circuit) that allows power to be supplied to the microcomputer 602 when ON but prohibits power to the microcomputer 602 when OFF, and a battery protection switch circuit 624 (an example of a second switch circuit) that allows discharge from the battery 628 when ON but prohibits discharge from the battery 628 when OFF.

[0417] If the beacon 582 is left unused for an extended period with the battery 628 attached to the battery port 610, the remaining charge in the battery 628 may decrease due to natural discharge. According to the above configuration, in addition to the power switch circuit 632, which switches between enabling and disabling power to the microcomputer 602 (i.e., turning the power on and off), a battery protection switch circuit 624 is provided to enable and disable discharge from the battery 628. This configuration prevents natural discharge from the battery 628 by pre-setting the battery protection switch circuit 624 off. Therefore, by pre-setting the battery protection switch circuit 624 off when the beacon 582 is left unused for an extended period, the remaining charge in the battery 628 can be prevented from decreasing.

[0418] In one or more embodiments, a battery protection switch circuit 624 and a power switch circuit 632 are arranged in series on a line (first conductive line 614 , connection point 620 , second conductive line 616 ) supplying power from the battery interface 610 to the microcomputer 602 .

[0419] According to the above configuration, by turning off the battery protection switch circuit 624 in advance, the supply of power to the microcomputer 602 can be prohibited regardless of the on / off state of the power switch circuit 632 .

[0420] In one or more embodiments, the power switch circuit 632 is a MOSFET (an example of an electronic switch). The battery protection switch circuit 624 is a MOSFET (an example of an electronic switch).

[0421] According to the above configuration, for example, the power switch circuit 632 (battery protection switch circuit 624 ) can be miniaturized compared to a case where the power switch circuit 632 (battery protection switch circuit 624 ) is a mechanical switch.

[0422] In one or more embodiments, the beacon 582 further includes a USB port 612 to which a USB cable can be connected. Power is supplied to the beacon 582 from the USB cable via the USB port 612, thereby switching the battery protection switch circuit 624 from OFF to ON.

[0423] According to the above configuration, the battery protection switch circuit 624 can be switched from OFF to ON by a relatively simple operation of connecting the USB cable to the USB port 612 .

[0424] In one or more embodiments, the battery 628 is a rechargeable secondary battery.

[0425] If battery 628 is a secondary battery, it may be difficult to remove battery 628 from beacon 582. Therefore, if battery 628 is stored attached to beacon 582, natural discharge of battery 628 may occur while beacon 582 is stored. In response to this, the above configuration prevents natural discharge of battery 628 by turning off battery protection switch circuit 624 before storing beacon 582.

Claims

1. A transport vehicle, characterized in that: The transport vehicle includes: a vehicle body unit; a grounding portion supported by the vehicle body unit and in contact with the ground; a power machine that drives the grounding portion; a first antenna; and a second antenna that is different from the first antenna. The transport vehicle includes: a first UWB anchor point that receives a beacon signal from a UWB tag carried by a user; a second UWB anchor point that is located at a different position in the front-rear direction from the first UWB anchor point and receives the beacon signal from the UWB tag; and a control unit that drives the power machine and can perform follow-up driving to move following the UWB tag. The control unit calculates a first distance between the first UWB anchor point and the UWB tag, and a first tag angle of the UWB tag relative to the first UWB anchor point, using the beacon signal received by the first antenna and the beacon signal received by the second antenna.

2. The transport vehicle according to claim 1, wherein: The control unit uses the beacon signal received by the second UWB anchor point to calculate a second distance between the second UWB anchor point and the UWB tag, and then uses the first distance and the second distance to determine whether the UWB tag is in a first area or a second area different from the first area.

3. The transport vehicle according to claim 2, characterized in that: The first UWB anchor point is arranged at a position closer to the front side than the second UWB anchor point. The first antenna and the second antenna are arranged in a left-right direction, In the left-right direction, the midpoint between the first antenna and the second antenna coincides with the center of the second UWB anchor point. The control unit determines that the UWB tag is in the first area when the second tag angle between the first imaginary line connecting the first UWB anchor point and the UWB tag and the second imaginary line connecting the first UWB anchor point and the second UWB anchor point is an obtuse angle, and determines that the UWB tag is in the second area when the second tag angle is 90° or an acute angle.

4. The transport vehicle according to claim 2 or 3, characterized in that: The first area is a follow-up driving permission area in which the follow-up driving is permitted. The second area is a follow-up driving prohibition area where execution of the follow-up driving is prohibited.

5. The transport vehicle according to claim 4, characterized in that: When determining that the UWB tag is in the follow-up driving permission area, the control unit calculates a target speed and a target angular speed using the first distance and the first tag angle, thereby controlling the operation of the power machine.

6. The transport vehicle according to claim 5, characterized in that: The control unit stops the operation of the power machine when it is determined that the UWB tag has moved from the following driving allowed area to the following driving prohibited area, and drives the power machine when it is determined that the UWB tag has moved from the following driving prohibited area to the following driving allowed area.

7. The transport vehicle according to any one of claims 1 to 6, characterized in that: The reception sensitivity for a signal from the front side of the first UWB anchor point is greater than the reception sensitivity for a signal from the rear side of the first UWB anchor point.

8. The transport vehicle according to any one of claims 1 to 7, characterized in that: The transport vehicle further includes: a cargo platform supported by the vehicle body unit; The front UWB anchor point located on the front side of the first UWB anchor point and the second UWB anchor point is arranged at a position closer to the front side than the shelf.

9. The transport vehicle according to claim 8, characterized in that: The rear UWB anchor point located at the rear side of the first UWB anchor point and the second UWB anchor point is arranged at a position further rearward than the shelf platform. The rear UWB anchor point is located above the front UWB anchor point and the shelf.

10. The transport vehicle according to claim 9, characterized in that: The transport vehicle further comprises a handle having a grip portion for the user to grip. The handlebar is arranged above the shelf. The rear UWB anchor point is provided on the handlebar.

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