Transport vehicle

Abstract

To provide a technique that can accurately calculate a user's position.SOLUTION: A transport vehicle disclosed in the present specification includes: a vehicle body unit; a grounding part that is supported by the vehicle body unit and is grounded on the ground; a motor that drives the grounding part; a first UWB anchor that has a first antenna and a second antenna different from the first antenna and receives a beacon signal from an UWB tag carried by a user; a second UWB anchor that is located differently in a front-to-back direction from the first UWB anchor and receives the beacon signal from the UWB tag; and a control unit that drives the motor to execute follow-up operation of moving by following the UWB tag. The control unit uses the beacon signal received by the first antenna and the beacon signal received by the second antenna to calculate a first distance between the first UWB anchor and the UWB tag and a first tag angle of the UWB tag relative to the first UWB anchor.SELECTED DRAWING: Figure 11

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a transport vehicle. This transport vehicle includes a body unit, a ground contact part supported by the body unit and in contact with the ground, a motor for driving the ground contact part, an anchor for receiving beacon signals from tags carried by users, and a control unit capable of driving the motor to perform a tracking operation in which the transport vehicle moves while tracking the tag. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-13129 Summary of the Invention [Problem to be solved by the invention]

[0004] In a transport vehicle capable of performing follow-up driving, it is desirable to accurately calculate the position of the tag, i.e., the position of the user. This specification provides a technology that can accurately calculate the position of the user. [Means for solving the problem]

[0005] The transporter disclosed in this specification may include a body unit, a grounding section supported by the body unit and in contact with the ground, a prime mover for driving the grounding section, a first UWB anchor having a first antenna and a second antenna different from the first antenna and configured to receive a beacon signal from a UWB tag carried by a user, a second UWB anchor positioned differently from the first UWB anchor in a longitudinal direction and configured to receive the beacon signal from the UWB tag, and a control unit capable of driving the prime mover to perform a tracking operation to move and track the UWB tag. The control unit may calculate a first distance between the first UWB anchor and the UWB tag and a first tag angle of the UWB tag relative to the first UWB anchor using the beacon signal received by the first antenna and the beacon signal received by the second antenna.

[0006] According to the above configuration, by using the first UWB anchor and the second UWB anchor that are positioned differently in the front-rear direction, the position of the UWB tag, that is, the position of the user, can be calculated with high accuracy. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view of a transporter 2 according to an embodiment, seen from the upper right front. [Figure 2] FIG. 2 is a left side view of the transporter 2 according to the embodiment. [Figure 3] 2 is a perspective view of a body unit 4 according to the embodiment, seen from the upper right front. FIG. [Figure 4] 10 is a cross-sectional view of a right-front overload detection mechanism 26A according to an embodiment, as viewed from the upper right front. FIG. [Figure 5] FIG. 2 is a diagram showing a control configuration of the transporter 2 according to the embodiment. [Figure 6] FIG. 2 is a right cross-sectional view of a housing 72 according to the embodiment. [Figure 7] FIG. 10 is a front view of a front UWB anchor 78 according to an embodiment. [Figure 8] FIG. 2 is a front cross-sectional view of a central switch box 98 according to the embodiment. [Figure 9] FIG. 2 is a right cross-sectional view of the central switch box 98 according to the embodiment. [Figure 10] FIG. 10 is a front view of a rear UWB anchor 108 according to an embodiment. [Figure 11] FIG. 10 is a flowchart of a follow-up mode process according to the embodiment. [Figure 12] FIG. 10 is a diagram showing a situation in which the UWB tag 200 is located in a following driving permitted area. [Figure 13] 10 is a diagram showing a transmission path of a beacon signal when the UWB tag 200 is located in a following driving prohibited area. [Figure 14] FIG. 10 is a diagram showing a situation in which the UWB tag 200 is located in a following driving prohibited area. [Figure 15] FIG. 3 is a schematic diagram of a transporter 302 according to a first reference example. [Figure 16] FIG. 10 is a flowchart of a follow-up mode process according to the first reference example. [Figure 17] 10 is a schematic diagram showing the relationship between a UWB tag 200 and radio wave intensity in Reference Example 1. FIG. [Figure 18] FIG. 10 is a schematic diagram of a transporter 402 according to a second reference example. [Figure 19] FIG. 10 is a flowchart of a follow-up mode process according to the second reference example. [Figure 20] 10 is a diagram showing a situation in which the UWB tag 200 is located to the right of the transport vehicle 402 in the second reference example. [Figure 21] 10 is a diagram showing a situation in which the UWB tag 200 is located to the left of the transport vehicle 402 in the second reference example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Representative, non-limiting embodiments of the present invention are described in detail below with reference to the drawings. This detailed description is intended simply to provide those skilled in the art with details for implementing preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Additionally, additional features and inventions disclosed below can be used separately or in conjunction with other features and inventions to provide further improved transport vehicles, methods of making and using the same.

[0009] Furthermore, the combinations of features and steps disclosed in the following detailed description are not essential to practicing the invention in its broadest sense, but are described solely to specifically illustrate exemplary embodiments of the invention. Furthermore, the various features of the exemplary embodiments described above and below, and those described in the independent and dependent claims, do not necessarily have to be combined in the exact embodiments described herein, or in the exact order listed, to provide additional and useful embodiments of the invention.

[0010] All features described in this specification and / or claims are intended to be disclosed individually and independently of one another as limitations on the original disclosure and claimed particulars, apart from any configuration of features described in the examples and / or claims. Furthermore, all numerical ranges and group or aggregation descriptions are intended to disclose intermediate configurations thereof as limitations on the original disclosure and claimed particulars.

[0011] In one or more embodiments, a transporter may include a body unit, a grounding portion supported by the body unit and in contact with the ground, a prime mover for driving the grounding portion, a first UWB anchor having a first antenna and a second antenna different from the first antenna and configured to receive a beacon signal from a UWB tag carried by a user, a second UWB anchor positioned differently from the first UWB anchor in a longitudinal direction and configured to receive the beacon signal from the UWB tag, and a control unit capable of driving the prime mover to perform a tracking operation to follow the UWB tag. The control unit may calculate a first distance between the first UWB anchor and the UWB tag and a first tag angle of the UWB tag relative to the first UWB anchor using the beacon signal received by the first antenna and the beacon signal received by the second antenna.

[0012] In one or more embodiments, the control unit may use the beacon signal received by the second UWB anchor to calculate a second distance between the second UWB anchor and the UWB tag, and use the first distance and the second distance to determine whether the UWB tag is located in a first area or a second area different from the first area.

[0013] According to the above configuration, by using the first UWB anchor and the second UWB anchor that are positioned at different positions in the forward and backward directions, it is possible to accurately determine whether the user is located in the first area or the second area.

[0014] In one or more embodiments, the first UWB anchor may be located forward of the second UWB anchor. The first antenna and the second antenna may be aligned in the left-right direction. In the left-right direction, a midpoint between the first antenna and the second antenna may coincide with a center position of the second UWB anchor. The control unit may determine that the UWB tag is located in the first area when a second tag angle between a first virtual line connecting the first UWB anchor and the UWB tag and a second virtual line connecting the first UWB anchor and the second UWB anchor is an obtuse angle, and may determine that the UWB tag is located in the second area when the second tag angle is 90° or an acute angle.

[0015] The first area may be an area in which the user is located in front of the first UWB anchor, and the second area may be an area in which the user is located directly beside the first UWB anchor or behind the first UWB anchor. When the second tag angle is an obtuse angle, the user is located in front of the first UWB anchor, when the second tag angle is 90°, the user is located directly beside the first UWB anchor, and when the second tag angle is an acute angle, the user is located behind the first UWB anchor. Therefore, it is possible to accurately determine whether the user is located in the first area or the second area.

[0016] In one or more embodiments, the first area may be a following driving permitted area in which the following driving is permitted, and the second area may be a following driving prohibited area in which the following driving is prohibited.

[0017] According to the above configuration, the user can cause the transport vehicle to perform follow-up driving only when the user is located in the follow-up driving permitted area.

[0018] In one or more embodiments, when the control unit determines that the UWB tag is located in the following operation permitted area, it may use the first distance and the first tag angle to calculate a target speed and a target angular speed and control the operation of the prime mover.

[0019] According to the above configuration, when the user is located in the follow-up driving permitted area, the transporter can be operated to follow the user.

[0020] In one or more embodiments, the control unit may stop operation of the prime mover when it determines that the UWB tag has moved from the following driving permitted area to the following driving prohibited area, and may drive the prime mover when it determines that the UWB tag has moved from the following driving prohibited area to the following driving permitted area.

[0021] According to the above configuration, it is possible to prevent the transport vehicle from traveling when the user is in a follow-up driving prohibited area, and therefore it is possible to make the transport vehicle appropriately perform follow-up driving.

[0022] In one or more embodiments, the first UWB anchor may have higher reception sensitivity for signals coming from the front side than for signals coming from the rear side.

[0023] According to the above configuration, the possibility of receiving a beacon signal transmitted from a UWB tag located in a following driving prohibited area is reduced. In this case, if the beacon signal is not received, the control unit can determine that the UWB tag is located in the following driving prohibited area. Therefore, it is possible to easily determine whether the UWB tag is located in the following driving prohibited area.

[0024] In one or more embodiments, the transporter may further include a loading platform supported by the vehicle body unit. A front UWB anchor located forward of the first UWB anchor and the second UWB anchor may be disposed forward of the loading platform.

[0025] The loading platform is used to carry luggage and other items. The beacon signal from the UWB tag may be blocked by the luggage on the loading platform, preventing the front UWB anchor from receiving the beacon signal. With the above configuration, the beacon signal from the UWB tag is not blocked by the luggage on the loading platform, increasing the probability that the front UWB anchor will receive the beacon signal.

[0026] In one or more embodiments, the rear UWB anchor, which is located rearward of the first UWB anchor and the second UWB anchor, may be positioned rearward of the loading platform, and the rear UWB anchor may be positioned above the front UWB anchor and the loading platform.

[0027] The beacon signal from the UWB tag may be blocked by the loading platform, preventing the rear UWB anchor from receiving the beacon signal. With the above configuration, the signal from the UWB tag is not blocked by luggage loaded on the loading platform, increasing the probability that the rear UWB anchor will receive the signal from the UWB tag.

[0028] In one or more embodiments, the transport vehicle may further include a handle having a grip portion for the user to grasp, the handle being positioned above the loading platform, and the rear UWB anchor being provided on the handle.

[0029] According to the above configuration, the rear UWB anchor can be easily disposed above the loading platform.

[0030] (Example) The transporter 2 shown in Fig. 1 includes a body unit 4, a loading platform 6, a handle 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. 2). The loading platform 6, the handle 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 body unit 4.

[0031] As shown in FIG. 3, the body unit 4 includes a first front frame 20A, a first rear frame 20B, a right frame 20C, a left 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 to the first front frame 20A from below at both left and right ends. The second rear frame 22B is fixed to the first rear frame 20B from below at both left and right ends. The right frame 20C and the left frame 20D extend in the front-rear direction. The right frame 20C and the left frame 20D connect the first front frame 20A and the first rear frame 20B. The right frame 20C is disposed to the right of the center position of the first front frame 20A in the left-right direction, and the left frame 20D is disposed to the left of the center position of the first front frame 20A in the left-right direction.

[0032] The body unit 4 further includes a front subframe 24A, a rear subframe 24B, a right subframe 24C, a left subframe 24D, a handle support plate 24E, and an overload detection mechanism 26. The overload detection mechanism 26 includes a right front overload detection mechanism 26A, a left front overload detection mechanism 26B, a right rear overload detection mechanism 26C, and a left rear overload detection mechanism 26D.

[0033] The front subframe 24A, rear subframe 24B, right subframe 24C, and left subframe 24D are disposed below the second front frame 22A and 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-rear direction. The right subframe 24C connects the right end of the front subframe 24A to 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 a right front overload detection mechanism 26A. The rear portion of the right subframe 24C is attached to the second rear frame 22B via a right rear overload detection mechanism 26C. The left subframe 24D connects the left end of the front subframe 24A to the left end of the rear subframe 24B. The front portion of the left subframe 24D is attached to the second front frame 22A via a left-front overload detection mechanism 26B. The rear portion of the left subframe 24D is attached to the second rear frame 22B via a left-rear overload detection mechanism 26D.

[0034] The right front overload detection mechanism 26A, the left front overload detection mechanism 26B, the right rear overload detection mechanism 26C, and the left rear overload detection mechanism 26D all have the same configuration. In the following, only the right front overload detection mechanism 26A will be described, and descriptions of the left front overload detection mechanism 26B, the right rear overload detection mechanism 26C, and the left rear overload detection mechanism 26D will be omitted.

[0035] As shown in FIG. 4, the right front overload detection mechanism 26A includes a base portion 30, a buffer member 31, a housing portion 32, a cap portion 34, a shaft 36, a coil spring 38, a detection plate 40, and a detection sensor 42.

[0036] The base portion 30 includes a first cylindrical portion 30A, a first flange portion 30B extending outward from the outer circumferential surface of the first cylindrical portion 30A, and an inner protrusion 30C extending inward from the inner circumferential surface of the lower end of the first cylindrical portion 30A. A first hole 30D having a diameter smaller than the inner diameter of the first cylindrical portion 30A is defined by the inner protrusion 30C. A buffer member 31 is attached to the upper portion of the base portion 30.

[0037] The housing portion 32 includes a second cylindrical portion 32A and a second flange portion 32B extending outward from the outer peripheral 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 subframe 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 passes through the first frame hole 28A in the up-down direction. The diameter of the second flange portion 32B is the same as the diameter 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 against the upper surface of the second flange portion 32B. The upper surface of the right subframe 24C abuts against the lower surface of the second flange portion 32B. The cap portion 34 is screwed onto the second cylindrical portion 32A from below.

[0038] 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 passes through the second frame hole 28B in the vertical direction. The diameter of the second shaft portion 36B is larger than the diameter of the first shaft portion 36A. The second shaft portion 36B is slidable in the vertical direction inside the first cylindrical portion 30A of the base 30. The diameter of the third shaft portion 36C is smaller than the diameter of the second shaft portion 36B. An upper bolt hole 36D is provided at the upper portion of the shaft 36, and a lower bolt hole 36E is provided at the lower portion. A first bolt 44, to which a spacer 46 is attached, is threadedly engaged in the upper bolt hole 36D. A second bolt 48 is threaded into the lower bolt hole 36E via the detection plate 40. The coil spring 38 is disposed between the third shaft portion 36C and the first cylindrical portion 30A of the base portion 30. The upper end of the coil spring 38 abuts against the lower surface of the second shaft portion 36B, and the lower end abuts against the upper surface of the inward protrusion 30C of the base portion 30.

[0039] The detection plate 40 includes a disc portion 40A having a second hole 40B in the center, and a detection portion 40C. The detection portion 40C extends downward from both the front and rear ends of the disc portion 40A. The disc portion 40A is disposed between a second bolt 48 and the third shaft portion 36C of the shaft 36 in the up-down direction. The shaft 36 and the detection plate 40 are fixed to the shaft 36 by the second bolt 48. In other words, the shaft 36 and the detection plate 40 move together.

[0040] The detection sensor 42 is a so-called photointerrupter. The detection sensor 42 includes a light-emitting element 50 and a light-receiving element 52 arranged opposite each other. The detection sensor 42 is turned off when there is no obstruction between the light-emitting element 50 and the light-receiving element 52, and is turned on when there is obstruction between the light-emitting element 50 and the light-receiving element 52. The detection sensor 42 is electrically connected to a main control unit 60 (see FIG. 5). The main control unit 60 in FIG. 5 applies a pulsed voltage to the light-emitting element 50. Specifically, the main control unit 60 switches between a state in which a voltage is applied to the light-emitting element 50 and a state in which no voltage is applied, at predetermined intervals. This causes the light-emitting element 50 to emit light intermittently, i.e., to flash.

[0041] As shown in FIG. 4, when no luggage is loaded on the loading platform 6 and no load from the loading platform 6 acts on the shaft 36, the upper surface of the disk portion 40A of the detection plate 40 abuts against the lower surface of the inward protrusion 30C of the base portion 30 due to the biasing force of the coil spring 38. In this state, the detection portion 40C of the detection plate 40 does not block the space between 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 detection sensor 42 transmits an ON signal and an OFF signal at predetermined intervals. The main control unit 60 in FIG. 5 determines that an overload does not occur when it receives an ON signal and an OFF signal from the detection sensor 42 at predetermined intervals.

[0042] Furthermore, when luggage is placed on the loading platform 6 from the state shown in FIG. 4 and a load from the loading platform 6 acts on the second front frame 22A, the shaft 36 and the detection plate 40 move downward relative to the base portion 30 against the biasing force of the coil spring 38. At this time, if a load equal to or greater than a predetermined upper load limit acts on the shaft 36, the detection portion 40C of the detection plate 40 is positioned between the light-emitting element 50 and the light-receiving element 52. As a result, the light from the light-emitting element 50 is blocked by the detection portion 40C. As a result, the light-receiving element 52 does not receive light. In this case, the detection sensor 42 continuously transmits an OFF signal to the main control unit 60 (see FIG. 5). Furthermore, if the electrical wiring connected to the light-emitting element 50 is disconnected, the light-emitting element 50 does not emit light and the light-receiving element 52 does not receive light. In this case, the detection sensor 42 also continuously transmits an OFF signal to the main control unit 60 (see FIG. 5). Therefore, when the main control unit 60 in FIG. 5 receives an OFF signal continuously from the detection sensor 42, it determines that an overload has occurred or that the electrical wiring has been broken.

[0043] Furthermore, if a short circuit occurs in the connector connected to the light-emitting element 50 in Fig. 4, 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 detection sensor 42 continuously transmits an ON signal to the main control unit 60 (see Fig. 5). Then, when the main control unit 60 in Fig. 5 continuously receives the ON signal from the detection sensor 42, it determines that a short circuit has occurred in the connector or the like.

[0044] Let us assume that the light-emitting element 50 emits light continuously in a normal state where no abnormalities such as disconnection or short circuit have occurred. In this case, the light-emitting element 50 emits light continuously when there is no overload and when there is a short circuit. Therefore, when the main control unit 60 continuously receives an ON signal from the detection sensor 42, it cannot distinguish whether there is no overload or whether there is a short circuit. With the above configuration, the main control unit 60 can accurately distinguish between a case where there is no overload, a case where there is an overload, or a case where some abnormality has occurred, based on the information received from the detection sensor 42.

[0045] As shown in FIG. 1, the transporter 2 further includes a bumper 70, a housing 72, a right headlight 73A, and a left headlight 73B attached to the front of the body unit 4. As shown in FIG. 2, the bumper 70 and the housing 72 are disposed in front of the cargo bed 6. The housing 72 is disposed higher than the bumper 70. The front end of the housing 72 is located rearward of the front end of the bumper 70. The right headlight 73A is disposed on the right side of the bumper 70. The left headlight 73B is disposed on the left side of the bumper 70.

[0046] As shown in FIG. 6, the housing 72 is composed of a first front housing 74 and a first rear housing 76 fixed to the first front housing 74. A front UWB anchor 78 is accommodated in the housing 72. The front UWB anchor 78 complies with the UWB (Ultra Wide Band) standard. In the left-right direction, the center position of the front UWB anchor 78 coincides with the position of the transporter 2. As shown in FIG. 7, the front UWB anchor 78 includes a UWB board 80, a first antenna 82, a second antenna 84, an anchor control unit 86, and a shield 88 (see FIG. 6). The first antenna 82, the second antenna 84, and the anchor control unit 86 are disposed on the front side of the UWB board 80. The first antenna 82 and the second antenna 84 are disposed above the anchor control unit 86. The first antenna 82 and the second antenna 84 are disposed 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 center of the transporter 2 and the center of the front UWB anchor 78. The first antenna 82 is disposed to the right of the center of the UWB board 80 in the left-right direction. The second antenna 84 is disposed to the left of the center of the UWB board 80 in the left-right direction. As shown in FIG. 6 , a shield 88 is disposed on the rear surface of the UWB board 80. The shield 88 is a member that shields signals transmitted from the rear side of the front UWB anchor 78. The shield 88 makes the reception sensitivity for signals arriving from the front side of the front UWB anchor 78 lower than the reception sensitivity for signals arriving from the rear side of the front UWB anchor 78.

[0047] As shown in FIG. 1 , the handle unit 8 includes a fixed shaft 90, a connecting member 92, a support shaft 94, a handle portion 96, a central switch box 98, and a right switch box 100. The fixed shaft 90 is fixed to the handle support plate 24E of the body unit 4 and extends upward from the handle support plate 24E. The support shaft 94 extends in the vertical direction. The support shaft 94 is disposed rearward of the fixed shaft 90. The support shaft 94 is rotatably connected to the fixed shaft via the connecting member 92.

[0048] As shown in FIG. 8, the handle portion 96 is attached to the upper end of the support shaft 94. As shown in FIG. 1, the handle portion 96 includes a right grip 96A and a left grip 96B. The central switch box 98 is provided in the center of the handle portion 96 in the left-right direction. As shown in FIG. 9, 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 central switch box 98 accommodates a rear UWB anchor 108. The rear UWB anchor 108 complies with the UWB standard. In other words, the center position of the rear UWB anchor 108 in the left-right direction coincides with the center position of the front UWB anchor 78 (see FIG. 3) in the left-right direction. As shown in FIG. 10 , the rear UWB anchor 108 includes a UWB substrate 110, a third antenna 112, a fourth antenna 114, an anchor control unit 116, and a shield 118 (see FIG. 9 ). The third antenna 112, the fourth antenna 114, and the anchor control unit 116 are disposed on the front surface of the UWB substrate 110. The third antenna 112 and the fourth antenna 114 are disposed below the anchor control unit 116. The third antenna 112 and the fourth antenna 114 are disposed 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 center of the transporter 2 and the center of the rear UWB anchor 18. The third antenna 112 is disposed to the right of the center of the UWB substrate 110 in the left-right direction. The fourth antenna 114 is disposed to the left of the center of the UWB substrate 110 in the left-right direction. As shown in Fig. 9, the shield 118 is disposed on the rear surface of the UWB board 110. The shield 118 is a member that shields signals transmitted from the rear side of the rear UWB anchor 108. The shield 118 makes the reception sensitivity for signals arriving from the front side of the rear UWB anchor 108 lower than the reception sensitivity for signals arriving from the rear side of the front UWB anchor 78. As shown in Fig. 2, the central switch box 98 is disposed above the housing 72 and the loading platform 6.That is, the rear UWB anchor 108 in the central switch box 98 is disposed above the front UWB anchor 78 in the housing 72 and above the cargo bed 6 .

[0049] As shown in FIG. 1, the right switch box 100 is disposed between the right grip 96A and the central switch box 98. A taillight 101 is provided at the bottom of the right switch box 100. As shown in FIG. 5, the right switch box 100 is further provided with a main power switch 120, a traveling direction switch 122, and a speed switch 124. The main power switch 120 can switch the main power of the transporter 2 on and off. The traveling direction switch 122 can switch the traveling direction of the transporter 2 in manual mode. The speed switch 124 can switch the traveling speed of the transporter 2 in manual mode. The central switch box 98 is also provided with a mode switch 126 and an emergency stop switch 128. The mode switch 126 can switch the operation mode of the transporter 2 among manual mode, following mode, and parking mode. The emergency stop switch 128 can stop the transporter 2 from traveling.

[0050] A user can rotate the handle unit 8 while holding the right grip 96A and the left grip 96B of the handle unit 8 in Fig. 1 with both hands. As shown in Fig. 5, the transporter 2 is equipped with a handle angle sensor 130 that detects the rotation angle of the handle unit 8 as a handle angle, a steering mechanism 132 that steers the right front wheel 10A and the left front wheel 10B as steered wheels, and a steering motor 134 that drives the steering mechanism 132. The steering motor 134 is, for example, a brushless motor. The handle angle sensor 130, the steering mechanism 132, and the steering motor 134 are supported by the body unit 4 (see Fig. 1).

[0051] As shown in FIG. 1, the transporter 2 has a battery attachment section 136 provided on the vehicle body unit 4. A battery pack 138 (see FIG. 5) can be attached and detached to the battery attachment section 136. The battery pack 138 has secondary battery cells (not shown), such as lithium-ion battery cells, and can be recharged using a charger (not shown). The transporter 2 operates using power supplied from the battery pack 138 attached to the battery attachment section 136.

[0052] As shown in Fig. 5, the transporter 2 is equipped with 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 body unit 4 (see Fig. 1).

[0053] The walker 2 further includes a control power supply circuit 150. When the main power switch 120 is turned on, the control power supply circuit 150 allows the supply of power from the battery pack 138, and when the main power switch 120 is turned off, the control power supply circuit 150 prohibits the supply of power from the battery pack 138. The main control unit 60 controls the operation of the walker 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 applies a large current to the brake circuit while 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 rotating, thereby applying 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. The control power supply circuit 150, the main control unit 60, the motor drivers 160, 162, 164, 166, 168, and the brake circuit are supported by the body unit 4 (see FIG. 1).

[0054] The main control unit 60 is further electrically connected to four detection sensors 42, a front UWB anchor 78, and a rear UWB anchor .

[0055] The transporter 2 in FIG. 1 can operate in any one of a manual mode, a follow-up mode, and a parking mode. In the manual mode, the transporter 2 moves forward or backward in response to a user's operation while standing behind the body unit 4 and holding the handle unit 8 with both hands. In the follow-up mode, the transporter 2 moves while tracking a UWB tag 200 (see FIG. 12) carried by a user standing in front of the body unit 4. In the parking mode, the transporter 2 remains stopped in place without accepting commands from either the handle unit 8 or the UWB tag 200. The main control unit 60 of the transporter 2 is configured to prohibit the transporter 2 from traveling when it determines, based on information received from the detection sensor 42, that the transporter 2 is overloaded or that some abnormality has occurred in the transporter 2. That is, traveling in the manual mode and the follow-up mode is prohibited. The transporter 2 also comes to an emergency stop when the emergency stop switch 128 (see FIG. 5) is operated.

[0056] (Follow-up mode processing; Figure 11) The follow-up mode process executed by the main control unit 60 will be described with reference to Fig. 11. The main control unit 60 starts the process of Fig. 11 when the operation mode of the transporter 2 is set to the follow-up mode.

[0057] 12, when the front UWB anchor 78 receives a beacon signal transmitted from the UWB tag 200 via the first antenna 82 and the second antenna 84 (see FIG. 7), the front UWB anchor 78 calculates the distance from the front UWB anchor 78 to the UWB tag 200 (hereinafter referred to as the "first distance D1") and the angle of the UWB tag 200 relative to the front UWB anchor 78 (hereinafter referred to as the "first angle a1"). The first angle a1 is the angle between a straight line L0 extending in the front-to-rear direction and a first straight line L1 connecting the front UWB anchor 78 and the UWB tag 200. Specifically, the front UWB anchor 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. Known methods for calculating angles using phase differences include PDoA (abbreviation of Phase Differences of Arrival) and AoA (abbreviation of Angle of Arrival).

[0058] Furthermore, when the rear UWB anchor 108 receives a beacon signal transmitted from the UWB tag 200 via the third antenna 112 and the fourth antenna 114 (see FIG. 10 ), the rear UWB anchor 108 calculates the distance from the rear UWB anchor 108 to the UWB tag 200 (hereinafter referred to as the “second distance D2”) and the angle of the UWB tag 200 relative to the rear UWB anchor 108 (hereinafter referred to as the “second angle a2”). The second angle a2 is the angle between a straight line L0 extending in the front-to-rear direction and a second straight line L2 connecting the rear UWB anchor 108 and the UWB tag 200. The methods of calculating the second distance D2 and the second angle a2 are the same as the methods of calculating the first distance D1 and the first angle a1, respectively.

[0059] 11, the main control unit 60 acquires the first distance D1 and the first angle a1 from the front UWB anchor 78. Specifically, the main control unit 60 acquires the first distance D1 and the first angle a1 from the front UWB anchor 78 in response to supplying the front UWB anchor 78 with a first acquisition instruction for acquiring the first distance D1 and the first angle a1. Note that if the front UWB anchor 78 has not yet received a beacon signal from the UWB tag 200, the main control unit 60 acquires, from the front UWB anchor 78, non-reception information indicating that the beacon signal has not yet been received.

[0060] In S12, the main control unit 60 acquires the second distance D2 and the second angle a2 from the rear UWB anchor 108. Specifically, the main control unit 60 acquires the second distance D2 and the second angle a2 from the rear UWB anchor 108 in response to supplying the rear UWB anchor 108 with a second acquisition instruction for acquiring the second distance D2 and the second angle a2. Note that if the rear UWB anchor 108 has not yet received a beacon signal from the UWB tag 200, the main control unit 60 acquires, from the rear UWB anchor 108, non-reception information indicating that the beacon signal has not yet been received.

[0061] In S20, the main control unit 60 determines whether the UWB tag 200 is located in a follow-up operation permitted area. The follow-up operation permitted area is an area in which execution of follow-up operation, in which the UWB tag 200 moves while tracking the UWB tag 200, is permitted. As shown in FIG. 12, the follow-up operation permitted area is an area in front of the front UWB anchor 78. In addition, the areas directly to the side of the front UWB anchor 78 and behind the front UWB anchor 78 are follow-up operation prohibited areas in which execution of follow-up operation is prohibited. The main control unit 60 determines whether the UWB tag 200 is located in the follow-up operation permitted area using the first distance D1 acquired from the front UWB anchor 78, the second distance D2 acquired from the rear UWB anchor 108, and the third distance D3 between the front UWB anchor 78 and the rear UWB anchor 108. The third distance D3 is pre-stored in a memory (not shown) of the main control unit 60. 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 the third straight line L3 that connects the front UWB anchor 78 and the rear UWB anchor 108. In this embodiment, the third straight line L3 and the straight line L0 are parallel to each other.

[0062]

number

[0063] 12, a case will be described in which the UWB tag 200 is located forward of the front UWB anchor 78. In this case, the third angle a3 becomes an obtuse angle as the second distance D2 is longer than the first distance D1. Therefore, when the third angle a3 is an obtuse angle, it can be determined that the UWB tag 200 is located in the following operation permitted area.

[0064] 13 and 14, a case where the UWB tag 200 is located behind the front UWB anchor 78 will be described. In this embodiment, the front UWB anchor 78 and the rear UWB anchor 108 have shields 88 (see FIG. 6) and 118 (see FIG. 9), respectively. Therefore, as shown in FIG. 13, the first antenna 82 and the second antenna 84 of the front UWB anchor 78 and the third antenna 112 and the fourth antenna 114 of the rear UWB anchor 108 do not receive many of the beacon signals transmitted from the rear of the front UWB anchor 78 and the rear UWB anchor 108 (dashed arrows in FIG. 13). However, beacon signals from the rear sides of the front UWB anchor 78 and the rear UWB anchor 108 may sneak around to the front sides of the front UWB anchor 78 and the rear UWB anchor 108 and reach the first antenna 82 and the second antenna 84 of the front UWB anchor 78 and the third antenna 112 and the fourth antenna 114 of the rear UWB anchor 108 (solid arrows in FIG. 13 ). FIG. 14 is a diagram that clearly shows a situation in which beacon signals transmitted from the rear sides of the front UWB anchor 78 and the rear UWB anchor 108 sneak around to the front sides of the front UWB anchor 78 and the rear UWB anchor 108 and reach the first antenna 82 and the second antenna 84 of the front UWB anchor 78 and the third antenna 112 and the fourth antenna 114 of the rear UWB anchor 108. 14, the third angle a3 becomes an acute angle as the first distance D1 becomes longer than the second distance D2. Therefore, the third angle a3 can be used to identify that the UWB tag 200 is located in a following driving prohibited area. Note that the third angle a3 also becomes an acute angle when the UWB tag 200 is located forward of the front UWB anchor 78 and rearward of the rear UWB anchor 108.

[0065] 11, in 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 78. In this case, the main control unit 60 determines that the UWB tag 200 is located in a following-drive 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 not located forward of the front UWB anchor 78. In this case, the main control unit 60 determines that the UWB tag 200 is located in a following-drive prohibited area (NO in S20), and the process proceeds to S30.

[0066] Note that even if the main control unit 60 has already acquired non-reception information from the front UWB anchor 78 in S10 or has already acquired non-reception information from the rear UWB anchor 108 in S12, it determines that the UWB tag 200 is located in a following driving prohibited area (NO in S20), and the process proceeds to S30. This is because when non-reception information is acquired, it is highly likely that the UWB tag 200 is located behind the front UWB anchor 78 or the rear UWB anchor 108.

[0067] In S22, the main control unit 60 uses the first distance D1 and first angle a1 obtained from the front UWB anchor 78 to determine the target speed TV and target angular velocity Tω of the transport vehicle 2 so that the transport vehicle 2 tracks the UWB tag 200.

[0068] In S24, the main control unit 60 controls the operation of the transport vehicle 2. Specifically, 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 based on the target speed TV and the target angular velocity Tω. When S24 ends, the process returns to S10. For example, if the UWB tag 200 moves from a following driving prohibited area to a following driving permitted area while the transport vehicle 2 is stopped, 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 so that the transport vehicle 2 travels.

[0069] Furthermore, in S30, the main control section 60 sets the target speed TV and the target angular speed Tω of the transport vehicle 2 to zero. When S30 ends, the process proceeds to S24.

[0070] In S24 after S30, the main control unit 60 controls the operation of the transport vehicle 2 so that the transport vehicle 2 does not move. For example, if the UWB tag 200 moves from a following driving permitted area to a following driving prohibited area while the transport vehicle 2 is moving, the main control unit 60 controls the operation of the brake circuit so that the transport vehicle 2 stops. Furthermore, if the UWB tag 200 moves from a following driving permitted area to a following driving prohibited area while the transport vehicle 2 is stopped, the main control unit 60 does not drive 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.

[0071] As described above, the main control unit 60 can accurately determine whether the UWB tag 200 is located in a following-driving permitted area by using the first distance D1, the second distance D2, and the third distance D3. Therefore, when the UWB tag 200 is located in a following-driving prohibited area, the execution of following-driving can be suppressed.

[0072] Hereinafter, the main control unit 60 and the anchor control units 86 and 116 will be collectively referred to as the "control unit."

[0073] In one or more embodiments, the transport vehicle 2 includes a body unit 4, wheels 10 (an example of a "grounding portion") supported by the body unit 4 and in contact with the ground, a traction motor 140 (an example of a "prime mover") that drives the wheels 10, a first antenna 82, a second antenna 84, a front UWB anchor 78 (an example of a "first UWB anchor") that receives beacon signals from a UWB tag 200 carried by a user, a rear UWB anchor 108 (an example of a "second UWB anchor") that is positioned rearward of the front UWB anchor 78 and receives beacon signals from the UWB tag 200, and a control unit capable of driving the traction motor 140 to perform follow-up operation to move in line with 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 a first distance D1 between the front UWB anchor 78 and the UWB tag 200 and a first angle a1 (an example of a "first tag angle") of the UWB tag 200 relative to the front UWB anchor 78.

[0074] According to the above configuration, by using the front UWB anchor 78 and the rear UWB anchor 108 that are positioned at different positions in the front-rear direction, the position of the UWB tag 200, that is, the position of the user, can be calculated with high accuracy.

[0075] In one or more embodiments, the control unit uses the beacon signal received by the rear UWB anchor 108 to calculate a second distance D2 between the rear UWB anchor 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 a following driving permitted area (an example of a "first area") in which following driving is permitted, or a following driving prohibited area (an example of a "second area") in which following driving is prohibited.

[0076] According to the above configuration, by utilizing the front UWB anchor 78 and the rear UWB anchor 108, which are positioned at different positions in the front-to-rear direction, it is possible to accurately determine whether the user is located in a follow-up driving permitted area or a follow-up driving prohibited area. Furthermore, according to the above configuration, it is possible to cause the transporter 2 to perform follow-up driving only when the user is located in a follow-up driving permitted area.

[0077] In one or more embodiments, the front UWB anchor 78 is positioned forward of the rear UWB anchor 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 position of the rear UWB anchor 108. The control unit determines that the UWB tag 200 is located in a following-driving permitted area when a third angle a3 (an example of a "second tag angle") between a first straight line L1 (an example of a "first virtual line") connecting the front UWB anchor 78 and the UWB tag 200 and a third straight line L3 (an example of a "second virtual line") connecting the front UWB anchor 78 and the rear UWB anchor 108 is an obtuse angle, and determines that the UWB tag 200 is located in a following-driving prohibited area when the third angle a3 is 90° or an acute angle.

[0078] An area in which the user is located forward of the front UWB anchor 78 may be a following driving permitted area, and an area in which the user is located directly beside the front UWB anchor 78 or behind the front UWB anchor 78 may be a following driving prohibited area. When the third angle a3 is an obtuse angle, the user is located forward of the front UWB anchor 78, when the third angle a3 is 90°, the user is located directly beside the front UWB anchor 78, and when the third angle a3 is an acute angle, the user is located behind the front UWB anchor 78. Therefore, it is possible to accurately determine whether the user is located in a following driving permitted area or a following driving prohibited area.

[0079] In one or more embodiments, when the control unit determines that the UWB tag 200 is located in the following driving permitted area, it uses the first distance D1 and the first angle a1 to calculate the target speed TV and the target angular speed Tω and controls the operation of the traction motor 140.

[0080] According to the above configuration, when the user is located in the follow-up driving permitted area, the transporter 2 can be operated to follow up the user.

[0081] In one or more embodiments, the control unit stops operation of the traction motor 140 when it determines that the UWB tag 200 has moved from a following driving permitted area to a following driving prohibited area, and drives the traction motor 140 when it determines that the UWB tag 200 has moved from a following driving prohibited area to a following driving permitted area.

[0082] According to the above configuration, it is possible to prevent the transport vehicle 2 from traveling when the user is located in a follow-up driving prohibited area. Therefore, it is possible to make the transport vehicle 2 appropriately perform follow-up driving.

[0083] In one or more embodiments, the front UWB anchor 78 has a higher reception sensitivity to signals coming from the front side than to signals coming from the rear side.

[0084] The above configuration reduces the possibility of receiving a beacon signal transmitted from UWB tag 200 located in a following driving prohibited area. In this case, if the beacon signal is not received, the control unit can determine that UWB tag 200 is located in a following driving prohibited area. Therefore, it is possible to easily determine whether UWB tag 200 is located in a following driving prohibited area.

[0085] In one or more embodiments, the transporter 2 further includes a loading platform 6 supported by the body unit 4. The front UWB anchor 78 is located forward of the loading platform 6.

[0086] Baggage and the like are loaded on the loading platform 6. When the UWB tag is located at the front of the transporter 2 and the front UWB anchor 78 is located behind the loading platform 6, the beacon signal from the UWB tag 200 may be blocked by the baggage loaded on the loading platform 6, and the front UWB anchor 78 may not be able to receive the beacon signal. With the above configuration, the beacon signal from the UWB tag 200 is not blocked by the baggage loaded on the loading platform 6, thereby increasing the probability that the front UWB anchor 78 will receive the beacon signal.

[0087] In one or more embodiments, the rear UWB anchor 108 is positioned rearward of the cargo bed 6. The rear UWB anchor 108 is positioned above the front UWB anchor 78 and the cargo bed 6.

[0088] There are cases where the beacon signal from the UWB tag 200 is blocked by the loading platform 6, and the rear UWB anchor 108 is unable to receive the beacon signal. With the above configuration, the signal from the UWB tag 200 is not blocked by the luggage loaded on the loading platform 6, and therefore the probability that the rear anchor will receive the signal from the UWB tag 200 can be increased.

[0089] In one or more embodiments, the transporter 2 further includes a handle 96 having grip portions 96A, 96B for a user to grasp. The handle 96 is positioned above the loading platform 6, and the rear UWB anchor 108 is provided on the handle 96.

[0090] According to the above configuration, the rear UWB anchor 108 can be easily disposed above the loading platform 6.

[0091] (First Modification) Either the front UWB anchor 78 or the rear UWB anchor 108 may have only one antenna. In this modification, the main control unit 60 controls the operation of the transporter 2 using the distance and angle calculated by the UWB anchor having two antennas, either the front UWB anchor 78 or the rear UWB anchor 108.

[0092] (Second Modification) In S22 of FIG. 11, the control unit may determine the target speed TV and target angular speed Tω of the transporter 2 using the second distance D2 and second angle a2 acquired from the rear UWB anchor 108.

[0093] (Third Modification) In the left-right direction, the position of the center of the front UWB anchor 78 does not have to coincide with the position of the center of the rear UWB anchor 108. In this case, the control unit corrects the deviation between the position of the center of the front UWB anchor 78 and the position of the center of the rear UWB anchor 108, and executes the process of S20 in FIG.

[0094] (Fourth Modification) The control unit may use the first distance D1 and the second distance D2 to determine whether the UWB tag 200 is located in the following operation permitted area. For example, if the first distance D1 is greater than the second distance D2, the control unit determines that the UWB tag 200 is located in the following operation permitted area.

[0095] (Fifth Modification) The control unit may determine whether the UWB tag 200 is located in a follow-up driving permitted area even when the operation mode of the transporter 2 is the manual mode or the parking mode.

[0096] (Sixth Modification) At least one or both of the front UWB anchor 78 and the rear UWB anchor 108 may not be provided with the shields 88, 118.

[0097] (Seventh Modification) Both the front UWB anchor 78 and the rear UWB anchor 108 may be disposed in front of the loading platform 6, or may be disposed behind the loading platform 6. Furthermore, at least one of the front UWB anchor 78 and the rear UWB anchor 108 may be disposed on the side of the loading platform 6.

[0098] (Eighth Modification) The "prime mover" is not limited to the traction motor 140, but may be an engine or the like.

[0099] (Ninth Modification) The "ground contact portion" is not limited to a wheel, but may be a crawler or the like.

[0100] (Tenth Modification) The area ahead of the front UWB anchor 78 may be a forward following area where the transport vehicle 2 performs a forward following operation to follow the UWB tag 200, and the area behind the front UWB anchor 78 may be a reverse driving area where the transport vehicle 2 performs a reverse following operation to follow the UWB tag 200. In this case, the area directly to the side of the front UWB anchor 78 may be a stopping area where a following operation is not performed. In this modification, the "forward following area" and the "reverse following area" are examples of the "first area" and the "second area", respectively.

[0101] (Eleventh Modification) The area in front of the front UWB anchor 78 may be a front lighting area in which the right headlight 73A and the left headlight 73B are turned on, and the area behind the front UWB anchor 78 may be a rear lighting area in which the taillight 101 is turned on. In this case, the area directly to the side of the front UWB anchor 78 may be an unlit area in which the right headlight 73A, the left headlight 73B, and the taillight 101 are not turned on. In this modification, the "front lighting area" and the "rear lighting area" are examples of the "first area" and the "second area", respectively.

[0102] Further features of the transporter 2 disclosed in this embodiment are described below. (Feature 1-1) A light-emitting element; a light receiving element disposed opposite the light emitting element; a shielding plate capable of blocking light emitted from the light-emitting element; a control unit; The control unit applying a pulsed voltage to the light emitting element so that the light emitting element emits light intermittently; The light receiving element is When the shielding plate does not block the light emitted from the light-emitting element, the light emitted from the light-emitting element is intermittently received; When the shielding plate blocks the light emitted from the light-emitting element, the light emitted from the light-emitting element is not received. Detection device. (Feature 1-2) The light receiving element is A detection device described in feature 1-1, which 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. (Features 1-3) A transport vehicle, The loading platform and a grounding portion that contacts the ground; a prime mover that drives the ground contact portion; The detection device according to feature 1-1 or 1-2 attached to the loading platform; a control unit for controlling the operation of the prime mover; The control unit permitting the driving of the prime mover when a light receiving element of the detection device intermittently receives light emitted from the light emitting element; When the light receiving element does not receive the light emitted from the light emitting element, driving of the motor is prohibited. Transport vehicle. (Features 1-4) When a load equal to or greater than a predetermined upper limit load acts on a shielding plate of the detection device from the loading platform, the shielding plate blocks the light emitted from the light-emitting element of the detection device, A transport vehicle according to features 1-3, wherein when a load less than a predetermined upper limit load acts on the shielding plate from the loading platform, the light emitted from the light-emitting element is not blocked by the shielding plate.

[0103] The effects of the above features 1-1 to 1-4 will be explained.

[0104] In one or more embodiments, the overload detection mechanism 26 (an example of a "detection device") includes a light-emitting element 50, a light-receiving element 52 disposed opposite the light-emitting element 50, a detection plate 40 (an example of a "shielding plate") capable of blocking 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 detection plate 40 is not blocking the light emitted from the light-emitting element 50, and does not receive light emitted from the light-emitting element 50 when the detection plate 40 is blocking the light emitted from the light-emitting element 50.

[0105] According to the above configuration, the control unit can detect whether the detection plate 40 is blocking the light emitted from the light-emitting element 50 depending on whether the light-receiving element 52 is intermittently receiving the light emitted from the light-emitting element 50.

[0106] In one or more embodiments, the light receiving element 52 continuously receives light emitted from the light emitting element 50 when a short circuit abnormality occurs in the light emitting element 50 and the detection plate 40 does not block the light emitted from the light emitting element 50.

[0107] According to the above configuration, the control unit can detect that a short circuit abnormality has occurred in the light-emitting element 50 when the light-receiving element 52 continuously receives light emitted from the light-emitting element 50.

[0108] In one or more embodiments, the transporter 2 includes a loading platform 6, wheels 10 (an example of a "ground contact portion") that contact the ground, a travel motor 140 (an example of a "prime mover") that drives the wheels 10, an overload detection mechanism 26 (an example of a "detection device") that is attached to the loading platform 6, and a control unit that controls the operation of the travel motor 140. The control unit permits the travel motor 140 to operate when the light receiving element 52 intermittently receives light emitted from the light emitting element 50, and prohibits the travel motor 140 from operating when the light receiving element 52 does not receive light emitted from the light emitting element 50.

[0109] If the light receiving element 52 does not receive the light emitted from the light emitting element 50, there is a high possibility that some kind of abnormality has occurred in the transport vehicle 2. According to the above configuration, when some kind of abnormality has occurred in the transport vehicle 2, it is possible to appropriately prevent the transport vehicle 2 from traveling.

[0110] In one or more embodiments, when a load equal to or greater than a predetermined upper limit load acts on the detection plate 40 (an example of a "shielding plate") from the loading platform 6, the light emitted from the light-emitting element 50 is blocked by the detection plate 40, and when a load less than the predetermined upper limit load acts on the detection plate 40 from the loading platform 6, the light emitted from the light-emitting element 50 is not blocked by the detection plate 40.

[0111] Let us assume that the light-emitting element 50 emits continuous light under normal conditions without any abnormalities such as disconnections or short circuits. In this case, the light-emitting element 50 emits continuous light when there is no overload and when there is a short circuit. Therefore, when the main control unit 60 continuously receives an ON signal from the detection sensor 42, it cannot distinguish whether there is no overload or whether there is a short circuit. With the above configuration, the overload detection mechanism 26 can accurately determine whether there is an overload. Therefore, it is possible to appropriately prevent the transporter 2 from traveling when there is an overload.

[0112] (Modification 1-1) The "detection device" can be used not only in the transport vehicle 2 but also in a robot vacuum cleaner or the like.

[0113] (Reference example 1) The transporter 302 of Reference Example 1 will be described with reference to Figures 15 to 17. Below, differences between the transporter 302 of Reference Example 1 and the transporter 2 of the embodiment will be mainly described, and commonalities will not be described.

[0114] As shown in Fig. 15, the transporter 302 of Reference Example 1 differs from the transporter 2 of the above-described embodiment in that it does not have a rear UWB anchor 108. Furthermore, the main control unit 60 (see Fig. 5) of Reference Example 1 executes the follow-up mode processing of Fig. 16 instead of the follow-up mode processing of Fig. 12.

[0115] (Follow-up mode processing; Figure 16) The follow-up mode process executed by the main control unit 60 will be described with reference to Fig. 16. The main control unit 60 starts the process of Fig. 16 when the operation mode of the transport vehicle 302 is set to the follow-up mode.

[0116] In S110, the main control unit 60 acquires the first distance D1 and the first angle a1 from the front UWB anchor 78. Specifically, the main control unit 60 acquires the first distance D1 and the first angle a1 from the front UWB anchor 78 in response to supplying the front UWB anchor 78 with a first acquisition instruction for acquiring the first distance D1 and the first angle a1. Note that if the front UWB anchor 78 has not yet received a beacon signal from the UWB tag 200, the main control unit 60 acquires, from the front UWB anchor 78, non-reception information indicating that the beacon signal has not yet been received.

[0117] In S112, the main control unit 60 determines the radio wave intensity threshold using the first distance D1 acquired in S110. The radio wave intensity threshold is a threshold for determining whether the UWB tag 200 is located in a following operation permitted area. The main control unit 60 reduces the radio wave intensity threshold as the first distance D1 increases.

[0118] In S120 of FIG. 16, the main control unit 60 determines whether the UWB tag 200 is located in a following-operation permitted area. Specifically, the main control unit 60 determines whether the radio wave strength of the beacon signal received by the front UWB anchor 78 exceeds the radio wave strength threshold determined in S112. The radio wave strength of the beacon signal will be described with reference to FIG. 17. In this reference example, the front UWB anchor 78 has a shield 88 (see FIG. 6). Therefore, as shown in FIG. 17, the first antenna 82 and the second antenna 84 of the front UWB anchor 78 do not receive many of the beacon signals transmitted from the rear side of the front UWB anchor 78 (dotted arrows in FIG. 17). However, beacon signals from the rear side of the front UWB anchor 78 may detour to the front side of the front UWB anchor 78 and reach the first antenna 82 and the second antenna 84 (solid arrows in FIG. 17). The radio wave strength of the beacon signal weakens as it travels around to the front side of the front UWB anchor 78. For this reason, the radio wave strength of the beacon signal that travels around from the rear side of the front UWB anchor 78 to the front side of the front UWB anchor 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 around from the front side of the front UWB anchor 78 and reaches the first antenna 82 and the second antenna 84.

[0119] 16, if the radio wave intensity exceeds the radio wave intensity threshold, the main control unit 60 determines that the UWB tag 200 is located in a following driving permitted area (YES in S120), and the process proceeds to S122. On the other hand, if the radio wave intensity is equal to or less than the radio wave intensity threshold, the main control unit 60 determines that the UWB tag 200 is located in a following driving prohibited area (NO in S120), and the process proceeds to S140.

[0120] If the main control unit 60 has already acquired non-reception information from the front UWB anchor 78 in S110, it determines that the UWB tag 200 is located in a following driving prohibited area (NO in S120), and the process proceeds to S140. This is because if non-reception information is acquired, it is highly likely that the UWB tag 200 is located behind the front UWB anchor 78.

[0121] In S122, the main control unit 60 calculates a tentative target speed TTV and a target angular speed Tω using the first distance D1 and the first angle a1 so that the transport vehicle 2 tracks the UWB tag 200. Specifically, the main control unit 60 calculates the tentative 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 for stopping the transport vehicle 302 in front of the user. "ωg1" in equation (3) is the first angular speed gain.

[0122]

number

[0123]

number

[0124] 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) are the maximum speed and the second speed offset of the transporter 302. The second speed offset Vo2 is a value determined according to 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.

[0125]

number

[0126] In S126, the main control unit 60 determines whether the tentative target speed TTV exceeds the speed limit VL. If the main control unit 60 determines that the tentative 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 tentative target speed TTV does not exceed the speed limit VL (NO in S126), the process proceeds to S130.

[0127] In S128, the main control unit 60 determines the speed limit VL as the target speed TV.

[0128] In addition, in S130, the main control unit 60 determines the tentative target speed TTV as the target speed TV.

[0129] In S132, the main control unit 60 controls the operation of the transporter 302. Specifically, based on the target speed TV and the target angular speed Tω, the main control unit 60 controls the operations 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.

[0130] In addition, in S140, the main control unit 60 sets the target speed TV and the target angular speed Tω of the transport vehicle 302 to zero. When S140 ends, the process proceeds to S132.

[0131] In S132 after S140, the main control unit 60 prohibits the transport vehicle 302 from traveling.

[0132] As described above, the main control unit 60 can accurately determine whether the UWB tag 200 is located in a following-driving permitted area by using the radio wave intensity and the radio wave intensity threshold. Therefore, when the UWB tag 200 is located in a following-driving prohibited area, the execution of following-driving can be suppressed.

[0133] The features of the transport vehicle 302 disclosed in this reference example are as follows. (Feature 2-1) A transport vehicle, A body unit, a ground contact portion supported by the body unit and adapted to contact the ground; a prime mover that drives the ground contact portion; a UWB anchor that receives a beacon signal from a UWB tag carried by a user; a control unit; the UWB anchor has a higher reception sensitivity for a signal arriving from the front side than for a signal arriving from the rear side; The control unit determining whether the UWB tag is located ahead of the UWB anchor by using the radio wave intensity of the beacon signal received from the UWB tag; Transport vehicle. (Feature 2-2) the UWB anchor has a first antenna and a second antenna different from the first antenna; 2. The transport vehicle of claim 1, wherein the control unit calculates a distance between the UWB anchor and the UWB tag and an angle of the UWB tag relative to the UWB anchor using the beacon signal received by the first antenna and the beacon signal received by the second antenna. (Feature 2-3) The control unit If the radio wave intensity exceeds a radio wave intensity threshold, it is determined that the UWB tag is located forward of the UWB anchor; The transporter according to feature 2-1 or 2-2, wherein when the radio wave strength is equal to or less than the radio wave strength threshold, it is determined that the UWB tag is located behind the UWB anchor. (Feature 2-4) The control unit Calculating a distance between the UWB tag and the UWB anchor using the beacon signal received by the UWB anchor; The transporter according to feature 2-3, wherein the radio wave intensity threshold is set to be smaller as the distance increases. (Feature 2-5) a loading platform supported by the body unit; The transporter according to any one of Features 2-1 to 2-4, wherein the UWB anchor is positioned forward of the loading platform. (Feature 2-6) The transporter of any one of features 2-1 to 2-5, comprising only one UWB anchor. (Feature 2-7) The control unit When it is determined that the UWB tag is located ahead of the UWB anchor, it is determined that the UWB tag is located in a follow-up operation permitted area in which movement while tracking the UWB tag is permitted; When it is determined that the UWB tag is located behind the UWB anchor, it is determined that the UWB tag is located in a following driving prohibited area in which movement by tracking the UWB tag is prohibited; A transporter described in any one of features 2-1 to 2-6, which stops operation of the prime mover when it determines that the UWB tag has moved from the following driving permitted area to the following driving prohibited area.

[0134] The effects of the above features 2-1 to 2-7 will be explained.

[0135] In one or more embodiments, the transporter 302 includes a body unit 4, wheels 10 (an example of a "ground contact portion") supported by the body unit 4 and in contact with the ground, a traction motor 140 (an example of a "prime mover") that drives the wheels 10, a front UWB anchor 78 (an example of a "UWB anchor") that receives beacon signals from UWB tags 200 carried by users, and a control unit. The front UWB anchor 78 has a higher reception sensitivity for signals arriving from the front side than for signals arriving from the rear side. The control unit uses the radio wave intensity of the beacon signal received from the UWB tag 200 to determine whether the UWB tag 200 is located in front of the front UWB anchor 78.

[0136] According to the above configuration, it is possible to determine whether the UWB tag 200, that is, the user, is located in front of the front UWB anchor 78, using the radio wave intensity.

[0137] In one or more embodiments, the front UWB anchor 78 has a first antenna 82 and a second antenna 84. 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 a first distance D1 between the front UWB anchor 78 and the UWB tag 200 and a first angle a1 of the UWB tag 200 relative to the front UWB anchor 78.

[0138] According to the above configuration, the user's location can be determined more accurately.

[0139] In one or more embodiments, the control unit determines that the UWB tag 200 is located forward of the front UWB anchor 78 when the radio wave strength exceeds the radio wave strength threshold, and determines that the UWB tag 200 is located behind the front UWB anchor 78 when the radio wave strength is equal to or less than the radio wave strength threshold.

[0140] According to the above configuration, it is possible to more accurately determine whether the user is located in front of the front UWB anchor 78 or not.

[0141] In one or more embodiments, the control unit uses the beacon signal received by the front UWB anchor 78 to calculate a first distance D1 between the UWB tag 200 and the front UWB anchor 78, and the longer the first distance D1, the smaller the radio wave strength threshold is set.

[0142] The radio wave intensity decreases as the distance between the UWB tag 200 and the front UWB anchor 78 increases. Therefore, by decreasing the radio wave intensity threshold as the first distance D1 increases, it is possible to determine whether the user is located in front of the front UWB anchor 78, regardless of the distance between the UWB tag 200 and the front UWB anchor 78.

[0143] In one or more embodiments, the transporter 302 includes a cargo bed 6 supported on a body unit 4. The front UWB anchor 78 is located forward of the cargo bed 6.

[0144] Luggage and the like are loaded on the loading platform 6. When the UWB tag is located at the front of the transporter 2 and the front UWB anchor 78 is located behind the loading platform 6, the beacon signal from the UWB tag 200 may be blocked by the luggage loaded on the loading platform 6, and the front UWB anchor 78 may not be able to receive the beacon signal. With the above configuration, the beacon signal from the UWB tag 200 is not blocked by the luggage loaded on the loading platform 6, and therefore the probability that the front UWB anchor 78 will receive the beacon signal can be increased. Furthermore, because the reception sensitivity on the front side of the front UWB anchor 78 is higher than the reception sensitivity on the rear side, it is possible to accurately determine whether the user is located ahead of the front UWB anchor 78 by using radio wave intensity.

[0145] In one or more embodiments, the vehicle 302 includes only one front UWB anchor 78 .

[0146] 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 anchors are used to determine whether the user is located forward of the front UWB anchor 78.

[0147] In one or more embodiments, when the control unit determines that the UWB tag 200 is located forward of the front UWB anchor 78, it determines that the UWB tag 200 is located in a following driving permitted area where it is permitted to move while following the UWB tag 200; when the control unit determines that the UWB tag 200 is located behind the front UWB anchor 78, it determines that the UWB tag 200 is located in a following driving prohibited area where it is prohibited to move while following the UWB tag 200; and when the control unit determines that the UWB tag 200 has moved from the following driving permitted area to the following driving prohibited area, it stops operation of the driving motor 140.

[0148] According to the above configuration, when the user is located in a follow-up driving prohibited area, the transport vehicle 302 can be prevented from traveling. Therefore, the transport vehicle 302 can be made to appropriately perform follow-up driving.

[0149] (Variation 2-1) The transporter 302 of Reference Example 1 may have two or more UWB anchors. In this case, at least one of the two or more UWB anchors may have two antennas. Specifically, the UWB anchor for detecting radio wave intensity may be different from the UWB anchor for detecting the distance to the tag, etc.

[0150] (Modification 2-2) Regardless of the distance between the UWB tag 200 and the front UWB anchor 78, the radio wave intensity threshold may be constant.

[0151] (Modification 2-3) The front UWB anchor 78 in the first reference example may be disposed behind the loading platform 6.

[0152] (Variant 2-4) When the control unit determines that the UWB tag 200 is located forward of the front UWB anchor 78, it may determine that the UWB tag 200 is located in a forward following area where the transport vehicle 302 moves forward to follow the UWB tag 200, and when the control unit determines that the UWB tag 200 is located behind the front UWB anchor 78, it may determine that the UWB tag 200 is located in a reverse driving area where the transport vehicle 302 moves backward to follow the UWB tag 200.

[0153] (Variant 2-5) When the control unit determines that the UWB tag 200 is located forward of the front UWB anchor 78, it may determine that the UWB tag 200 is located in a front lighting area that turns on the right headlight 73A and the left headlight 73B, and when the control unit determines that the UWB tag 200 is located rearward of the front UWB anchor 78, it may determine that the UWB tag 200 is located in a rear lighting area that turns on the taillight 101.

[0154] (Reference example 2) 18 to 21, a description will be given of a transporter 402 of Reference Example 2. The following mainly describes the differences between the transporter 402 of Reference Example 2 and the transporter 2 of the embodiment, and a description of the commonalities will be omitted.

[0155] As shown in Fig. 18, the transporter 402 of Reference Example 2 differs from the transporter 2 of the above-described embodiment in that it has a right front UWB anchor 412 and a left front UWB anchor 410 instead of the front UWB anchor 78 (see Fig. 7) and the rear UWB anchor 108 (see Fig. 10). Also, the main control unit 60 (see Fig. 5) of Reference Example 2 executes the follow-up mode processing of Fig. 19 instead of the follow-up mode processing of Fig. 12.

[0156] The left front UWB anchor 410 and the right front UWB anchor 412 in FIG. 18 have the same configuration as the front UWB anchor 78 of the embodiment (see FIGS. 6 and 7). The left front UWB anchor 410 and the right front UWB anchor 412 are disposed within the housing 72 (see FIG. 1) of the transporter 402. That is, the left front UWB anchor 410 and the right front UWB anchor 412 are disposed forward of the loading platform 6 (see FIG. 1). The left front UWB anchor 410 is disposed to the left of the center position of the transporter 402 in the left-right direction. The right front UWB anchor 412 is disposed to the right of the center position of the transporter 402 in the left-right direction. In the left-right direction, the midpoint between the two antennas of the left front UWB anchor 410 and the midpoint between the two antennas of the right front UWB anchor 412 are located at equal intervals from the center position of the transporter 2.

[0157] (Follow-up mode processing; Figure 19) The follow-up mode process executed by the main control unit 60 will be described with reference to Fig. 19. The main control unit 60 starts the process of Fig. 19 when the operation mode of the transport vehicle 402 is set to the follow-up mode.

[0158] 20, when the left front UWB anchor 410 receives a beacon signal from the UWB tag 200, it calculates the distance from the left front UWB anchor 410 to the UWB tag 200 (hereinafter referred to as the "fourth distance D4"). When the right front UWB anchor 412 receives a beacon signal from the UWB tag 200, it calculates the distance from the right front UWB anchor 412 to the UWB tag 200 (hereinafter referred to as the "fifth distance D5"). The methods for calculating the fourth distance D4 and the fifth distance D5 are the same as the method for calculating the first distance D1 in the embodiment.

[0159] 19, the main control unit 60 acquires the fourth distance D4 from the left front UWB anchor 410. Specifically, the main control unit 60 acquires the fourth distance D4 from the left front UWB anchor 410 in response to supplying the left front UWB anchor 410 with a third acquisition instruction for acquiring the fourth distance D4. Note that if the left front UWB anchor 410 has not yet received a beacon signal from the UWB tag 200, the main control unit 60 acquires from the left front UWB anchor 410 unreceived information indicating that the beacon signal has not yet been received.

[0160] In S212, the main control unit 60 acquires a fifth distance D5 from the right front UWB anchor 412. Specifically, the main control unit 60 acquires the fifth distance D5 from the right front UWB anchor 412 in response to supplying a fourth acquisition instruction to the right front UWB anchor 412 for acquiring the fifth distance D5. Note that if the right front UWB anchor 412 has not yet received a beacon signal from the UWB tag 200, the main control unit 60 acquires from the right front UWB anchor 412 unreceived information indicating that the beacon signal has not yet been received.

[0161] In S214, the main control unit 60 determines whether the UWB tag 200 is located in the following driving permitted area. Specifically, the main control unit 60 determines whether it has acquired unreceived information from at least one of the left front UWB anchor 410 and the right front UWB anchor 412. If the main control unit 60 determines that it has not acquired unreceived information, it determines that the UWB tag 200 is located forward of the left front UWB anchor 410 and the right front UWB anchor 412. In this case, the main control unit 60 determines that the UWB tag 200 is located 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 it has acquired unreceived information, it determines that the UWB tag 200 is located rearward of the left front UWB anchor 410 and the right front UWB anchor 412. In this case, the main control unit 60 determines that the UWB tag 200 is located in the following driving prohibited area (YES in S214), and the process proceeds to S216.

[0162] In S216, the main control unit 60 sets the target speed TV and target angular velocity Tω of the cart 402 to zero, and stops the cart 302. When S216 ends, the process returns to S210.

[0163] Furthermore, in S220, the main control unit 60 determines whether the fourth distance D4 and the fifth distance D5 match. If the main control unit 60 determines that the fourth distance D4 and the fifth distance D5 match (YES in S220), the process proceeds to S222. Note that the fourth distance D4 and the fifth distance D5 match when the UWB tag 200 is located directly in front of the transporter 402. On the other hand, if the main control unit 60 determines that the fourth distance D4 and the fifth distance D5 do not match (NO in S220), the process proceeds to S230.

[0164] In S222, the main control unit 60 calculates the target speed TV of the transporter 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 value of the fourth distance D4 and the fifth distance D5, and the second speed gain, respectively.

[0165]

number

[0166] In S224, the main control unit 60 uses the target speed TV to move the transport vehicle 402 straight ahead. When S224 ends, the process returns to S210.

[0167] Furthermore, 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. Note that the fourth distance D4 is greater than the fifth distance D5 when the UWB tag 200 is located to the right of the center position of the transport vehicle 402 in the left-right direction, as shown in FIG. 20. 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. Note that the fourth distance D4 is not greater than the fifth distance D5 when the UWB tag 200 is located to the left of the center position of the transport vehicle 402 in the left-right direction, as shown in FIG. 21.

[0168] 19, in S232, the main control unit 60 calculates the target speed TV and the target angular speed Tω of the transport vehicle 402 so that the transport vehicle 402 tracks the UWB tag 200. The method for calculating the target speed TV in this step is the same as the method for calculating the target speed TV in S222. The main control unit 60 calculates the target angular speed Tω using the fourth distance D4, the fifth distance D5, and the following equation (6). "ωg2" in equation (6) is the second angular speed gain.

[0169]

number

[0170] In S234, the main control unit 60 uses the target speed TV and the target angular speed Tω to turn the transporter 402 to the right. When S234 ends, the process returns to S210.

[0171] In S240, the main control unit 60 calculates a target speed TV and a target angular speed Tω of the transport vehicle 402 so that the transport vehicle 402 tracks the UWB tag 200. The method for calculating the target speed TV in this step is the same as the method for calculating the target speed TV in S222. The method for calculating the target angular speed Tω in this step is the same as the method for calculating the target angular speed Tω in S232.

[0172] In S242, the main control unit 60 uses the target speed TV and the target angular speed Tω to turn the transport vehicle 402 to the left. When S242 ends, the process returns to S210.

[0173] As described above, the main control unit 60 can accurately determine whether the UWB tag 200 is located to the left or right of the center position of the transport vehicle 402 in the left-right direction by using the fourth distance D4 and the fifth distance D5.

[0174] The features of the transport vehicle 402 disclosed in this reference example are as follows. (Feature 3-1) A transport vehicle, A body unit, a ground contact portion supported by the body unit and adapted to contact the ground; a prime mover that drives the ground contact portion; a first UWB anchor that receives a beacon signal from a UWB tag carried by a user; a second UWB anchor disposed to the left of the first UWB anchor and configured to receive a beacon signal; a control unit capable of driving the prime mover to perform a tracking operation in which the UWB tag is tracked and moved; The control unit Calculating a first tag distance between the first UWB anchor and the UWB tag using the beacon signal received by the first UWB anchor; Calculating a second tag distance between the second UWB anchor and the UWB tag using the beacon signal received by the second UWB anchor; determining whether the UWB tag is located to the right of the vehicle or to the left of the vehicle based on the first tag distance and the second tag distance; Transport vehicle. (Feature 3-2) The control unit The transporter according to Feature 3-1, wherein a target angular velocity of the transporter is determined based on an absolute value of a difference between the first tag distance and the second tag distance. (Feature 3-3) The control unit The transporter according to feature 3-1 or 3-2, wherein a target speed of the transporter is determined based on an average value of the first tag distance and the second tag distance.

[0175] The effects of the above Features 3-1 to 3-3 will be explained.

[0176] In one or more embodiments, the transport vehicle 402 comprises a body unit 4, wheels 10 (an example of a "ground contact portion") supported by the body unit 4 and in contact with the ground, a traction motor 140 (an example of a "prime mover") that drives the wheels 10, a right front UWB anchor 412 (an example of a "first UWB anchor") that receives a beacon signal from a UWB tag 200 carried by a user, a left front UWB anchor 410 (an example of a "second UWB anchor") that is positioned to the left of the right front UWB anchor 412 and receives the beacon signal, and a control unit capable of driving the traction motor 140 to perform follow-up operation to move and follow the UWB tag 200. The control unit uses the beacon signal received by the right front UWB anchor 412 to calculate a fourth distance D4 (an example of a "first tag distance") between the right front UWB anchor 412 and the UWB tag 200, and uses the beacon signal received by the left front UWB anchor 410 to calculate a fifth distance D5 (an example of a "second tag distance") between the left front UWB anchor 410 and the UWB tag 200, 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 vehicle 402 or to the left of the transport vehicle 402.

[0177] According to the above configuration, by utilizing the right front UWB anchor 412 and the left front UWB anchor 410, which are positioned differently in the left-right direction, the left-right position of the UWB tag 200, i.e., the left-right position of the user, can be appropriately determined.

[0178] In one or more embodiments, the control unit determines the target angular velocity Tω of the vehicle based on the absolute value of the difference between the fourth distance D4 and the fifth distance D5.

[0179] According to the above configuration, the angular velocity of the cart 402 can be adjusted according to the distance between the cart 402 and the user.

[0180] In one or more embodiments, the control unit determines a target speed TV for the vehicle 402 based on an average value of the fourth distance D4 and the fifth distance D5.

[0181] According to the above configuration, the speed of the cart 402 can be adjusted according to the distance between the cart 402 and the user.

[0182] (3-1 Modification) At least one of right front UWB anchor 412 and left front UWB anchor 410 may have only one antenna.

[0183] (Modification 3-2) The positions of right front UWB anchor 412 and left front UWB anchor 410 in the front-rear direction may be different.

[0184] (3-3 Modification) The right front UWB anchor 412 and the left front UWB anchor 410 may be disposed rearward of the loading platform 6.

[0185] 19, the main control unit 60 may calculate the target speed TV using one of the fourth distance D4 and the fifth distance D5. Also, in S232 and S240, the main control unit 60 may calculate the target speed TV and the target angular speed Tω using one of the fourth distance D4 and the fifth distance D5. [Explanation of symbols]

[0186] 2: Transport vehicle 4: Body unit 6: Cargo bed 8: Handle unit 10: Wheels 10A: Right front wheel 10B:Left front wheel 10C: Right rear wheel 10D:Left rear wheel 20A: First front frame 20B: First rear frame 20C: Right frame 20D: Left frame 22A: Second front frame 22B: Second rear frame 24A: Front subframe 24B: Rear subframe 24C: Right side subframe 24D: Left subframe 24E: Handle support plate 26: Overload detection mechanism 26A: Right front overload detection mechanism 26B: Left front overload detection mechanism 26C: Right rear overload detection mechanism 26D: Left rear overload detection mechanism 28A: First frame hole 28B: Second frame hole 30: Base part 30A: First cylindrical part 30B: First flange part 30C: Inner protrusion 30D: 1st hole 31: Cushioning material 32: Housing part 32A: Second cylindrical part 32B: Second flange part 34: Cap part 36: Shaft 36A: First shaft section 36B: Second shaft section 36C: Third shaft section 36D: Upper bolt hole 36E: Lower bolt hole 38: Coil spring 40: Detection plate 40A: Disc part 40B: 2nd hole 40C:Detection unit 42: Detection sensor 44: First bolt 46: Spacer 48: Second bolt 50: Light emitting element 52: Light receiving element 60: Main control unit 70: Bumper 72: Housing 73A: Right headlight 73B:Left headlight 74: First front housing 76: 1st rear housing 78: Front UWB anchor 80: UWB board 82: First antenna 84: Second antenna 86: Anchor control unit 88: Shield 90: Fixed shaft 92: Connecting member 94: Support shaft 96: Handle 96A: Right grip 96B: Left grip 98: Central switch box 100: Right switch box 101:Taillight 102: Second front housing 104: Second rear housing 106: Upper plate 108: Rear UWB anchor 110: UWB board 112: Third antenna 114: 4th antenna 116: Anchor control unit 118: Shield 120: Main power switch 122: Direction switch 124: Speed ​​switch 126: Mode switch 128: Emergency stop switch 130: Steering wheel angle sensor 132: Steering mechanism 134: Steering motor 136: Battery mounting part 138: Battery pack 140:Traction motor 140A: Right front wheel motor 140B: Left front wheel motor 140C: Right rear wheel motor 140D: Left rear wheel motor 150: Control power circuit 160: Motor driver 162: Motor driver 164: Motor driver 166: Motor driver 168: Motor driver 200: UWB tag 302: Transport vehicle 402: Transport vehicle 410: Left front UWB anchor 412: Right front UWB anchor

Claims

1. A transport vehicle, A body unit, a ground contact portion supported by the body unit and adapted to contact the ground; a prime mover that drives the ground contact portion; a first UWB anchor having a first antenna and a second antenna different from the first antenna, for receiving a beacon signal from a UWB tag carried by a user; a second UWB anchor that is positioned differently from the first UWB anchor in a front-to-rear direction and receives the beacon signal from the UWB tag; a control unit capable of driving the prime mover to perform a tracking operation in which the prime mover moves while tracking the UWB tag; The control unit calculating a first distance between the first UWB anchor and the UWB tag and a first tag angle of the UWB tag relative to the first UWB anchor using the beacon signal received by the first antenna and the beacon signal received by the second antenna; Transport vehicle.

2. The control unit Calculating a second distance between the second UWB anchor and the UWB tag using the beacon signal received by the second UWB anchor; determining whether the UWB tag is located in a first area or a second area different from the first area by using the first distance and the second distance; 2. The vehicle of claim 1.

3. the first UWB anchor is disposed forward of the second UWB anchor, the first antenna and the second antenna are aligned in the left-right direction, a midpoint between the first antenna and the second antenna and a center of the second UWB anchor are aligned in the left-right direction; The control unit determining that the UWB tag is located in the first area when a second tag angle between a first virtual line connecting the first UWB anchor and the UWB tag and a second virtual line connecting the first UWB anchor and the second UWB anchor is an obtuse angle; The transporter according to claim 2 , wherein the UWB tag is determined to be located in the second area when the second tag angle is 90° or an acute angle.

4. the first area is a follow-up driving permission area in which execution of the follow-up driving is permitted, The transporter according to claim 2 or 3, wherein the second area is a follow-up driving prohibited area in which execution of the follow-up driving is prohibited.

5. The control unit A transport vehicle as described in claim 4, wherein when it is determined that the UWB tag is located in the following driving permitted area, the first distance and the first tag angle are used to calculate a target speed and a target angular speed, and the operation of the prime mover is controlled.

6. The control unit When it is determined that the UWB tag has moved from the following driving permitted area to the following driving prohibited area, the operation of the prime mover is stopped; The transporter according to claim 5 , wherein the motor is driven when it is determined that the UWB tag has moved from the following driving prohibited area to the following driving permitted area.

7. The transporter according to claim 1 , wherein the first UWB anchor has a higher reception sensitivity for signals arriving from the front side than for signals arriving from the rear side.

8. a loading platform supported by the body unit; The transporter according to claim 1 , wherein a front UWB anchor of the first UWB anchor and the second UWB anchor, which is located on the front side, is disposed forward of the loading platform.

9. a rear UWB anchor located rearward of the first UWB anchor and the second UWB anchor is disposed rearward of the loading platform; The transporter according to claim 8 , wherein the rear UWB anchor is located above the front UWB anchor and the loading platform.

10. a handle having a grip portion for the user to grasp; The handle is disposed above the carrier, The vehicle of claim 9 , wherein the rear UWB anchor is provided on the handle.

Images