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Abstract

This invention provides a technology that further improves the safety of a transport vehicle operating in automatic mode. The transport vehicle disclosed in this specification includes: a drive wheel; a motor that drives the drive wheel to rotate; a motor drive circuit configured to drive the motor; a control unit configured to control the motor via the motor drive circuit, such that the transport vehicle's travel speed is below a maximum travel speed; and an operating component disposed on the transport vehicle to receive operation by a user. The transport vehicle can operate in manual and automatic modes. In manual mode, the motor is driven when the operating component is engaged and stops when the operating component is disengaged. In automatic mode, the motor is driven regardless of whether the operating component is engaged or disengaged. The maximum travel speed in automatic mode can be set to be lower than the maximum travel speed in manual mode.

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. The transport vehicle includes: a drive wheel; a motor that rotates the drive wheel; a motor drive circuit configured to drive the motor; a control unit that controls the motor via the motor drive circuit at a travel speed below or above the maximum travel speed of the transport vehicle; and an operating component disposed on the transport vehicle for user operation. The transport vehicle can operate in a manual mode and an automatic mode. The manual mode is characterized by the motor being driven when the operating component is engaged and stopping when the operating component is disengaged; the automatic mode is characterized by the motor being driven regardless of whether the operating component is engaged or disengaged.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2003-038695 Summary of the Invention

[0006] When a transport vehicle operates in automatic mode, a higher level of safety is required compared to when it operates in manual mode. This specification provides a technology that further improves the safety of a transport vehicle operating in automatic mode.

[0007] The transport vehicle disclosed in this specification may include: drive wheels; a motor that drives the drive wheels to rotate; a motor drive circuit configured to control the motor; a motor control unit configured to control the motor by means of the motor drive circuit, such that the travel speed of the transport vehicle is below a maximum travel speed; and an operating component disposed on the transport vehicle for operation by a user. The transport vehicle can operate in manual mode and automatic mode. In manual mode, the motor is driven when the operating component is engaged and stops when the operating component is disengaged. In automatic mode, the motor is driven regardless of whether the operating component is engaged or disengaged. The maximum travel speed in automatic mode can be set to be lower than the maximum travel speed in manual mode.

[0008] Based on the above configuration, the upper limit of the travel speed of the transport vehicle when operating in automatic mode is set to be lower than the upper limit of the travel speed of the transport vehicle when operating in manual mode. Therefore, the safety of the transport vehicle when operating in automatic mode can be further improved. Attached Figure Description

[0009] Figure 1 This is a perspective view of the transport vehicle 2 involved in the embodiment, viewed from the upper right front.

[0010] Figure 2 This is a perspective view of the vehicle base unit 4 involved in the embodiment, viewed from the lower right front.

[0011] Figure 3 This is a perspective view of the vehicle base unit 4 involved in the embodiment, viewed from the upper right rear.

[0012] Figure 4 This is a perspective view of the right front overload monitoring mechanism 302a of the vehicle base unit 4 involved in the embodiment, as viewed from the right front upper view.

[0013] Figure 5 This is a longitudinal sectional view of the right front overload monitoring mechanism 302a on the vehicle base unit 4 involved in the embodiment, with the overload monitoring sensor 320a disconnected.

[0014] Figure 6 This is a longitudinal sectional view of the right front overload monitoring mechanism 302a on the vehicle base unit 4 involved in the embodiment, with the overload monitoring sensor 320a turned on.

[0015] Figure 7 This is a longitudinal sectional view of the overload monitoring mechanism 364 on the vehicle base unit 4 involved in the modified example, with the overload monitoring sensor 380 disconnected.

[0016] Figure 8 This is a longitudinal sectional view of the overload monitoring mechanism 364 on the vehicle base unit 4 in the modified example, with the overload monitoring sensor 380 turned on.

[0017] Figure 9 This is a cross-sectional view of the vehicle base unit 4 involved in the embodiment, observed at sections along the front-rear and vertical directions.

[0018] Figure 10 This is a cross-sectional view of the vehicle base unit 4 involved in the embodiment, observed at cross-sections along the left-right and up-down directions.

[0019] Figure 11 This is a perspective view of the handlebar unit 8 involved in the embodiment, viewed from the upper right rear.

[0020] Figure 12 This is a perspective view of the lower part of the handlebar unit 8 involved in the embodiment, as seen from the lower right front.

[0021] Figure 13 This is a perspective view of the support tube 78, clamping component 80, fixing component 82, handlebar shaft 84, and rotation angle sensor 88 of the handlebar unit 8 involved in the embodiment, as viewed from the lower right front.

[0022] Figure 14 This is a perspective view of the movable cam component 90 of the handlebar unit 8 involved in the embodiment, viewed from the upper left rear.

[0023] Figure 15 This is a perspective view of the fixed cam component 92 of the handlebar unit 8 involved in the embodiment, viewed from the upper left front.

[0024] Figure 16 This is a cross-sectional view of the lower part of the handlebar unit 8 of the embodiment, as observed in sections along the front-rear and left-right directions, in a state where a right turn operation has been performed.

[0025] Figure 17 This is a perspective view of the lower part of the handlebar unit 8 in the embodiment, as seen from the lower right front, in a state where a rightward turning operation has been performed.

[0026] Figure 18 This is a perspective view of the steering unit 10 and front wheel unit 12 involved in the embodiment, viewed from the upper left front.

[0027] Figure 19 This is a perspective view of the steering unit 10 involved in the embodiment, viewed from the upper left front.

[0028] Figure 20 This is a cross-sectional view of the steering unit 10 involved in the embodiment, observed in sections along the front-back and left-right directions.

[0029] Figure 21 This is an exploded perspective view of the main shaft 178, cam 180, movable gear 182, and coil spring 184 of the steering unit 10 involved in the embodiment, as viewed from the lower left rear.

[0030] Figure 22 This is a cross-sectional view of the steering unit 10 involved in the embodiment, observed in sections along the front-back and up-down directions.

[0031] Figure 23 This is a perspective view of the right front wheel unit 12a involved in the embodiment, viewed from the upper left front.

[0032] Figure 24 This is a cross-sectional view of the right front wheel unit 12a of the embodiment, as observed in sections along the left-right and up-down directions.

[0033] Figure 25 This is a perspective view of the rear wheel unit 14 of the embodiment, viewed from the upper right rear.

[0034] Figure 26 This is a perspective view of the right rear wheel unit 14a of the embodiment, viewed from the upper left rear.

[0035] Figure 27 This is a perspective view of the bumper unit 16 involved in the embodiment, viewed from the upper right front.

[0036] Figure 28 This is a cross-sectional view of the bumper unit 16 involved in the embodiment near the direct-drive bearing 522, observed in sections along the front-rear and left-right directions.

[0037] Figure 29 This is a perspective sectional view of the bumper unit 16 involved in the embodiment, viewed from the upper left rear.

[0038] Figure 30 This is a diagram that simulates the circuit configuration of the transport vehicle 2 involved in the embodiment.

[0039] Figure 31 This is a diagram that simulates the circuit configuration of the switching circuit 436 involved in the embodiment.

[0040] Figure 32 It is a diagram that simulates the circuit configuration of the cut-off circuit 438, motor drivers 454, 456, 458, 460, and braking circuits 468, 470, 472, 474 involved in the embodiment.

[0041] Figure 33 This is a diagram that simulates the circuit configuration of the cut-off circuit 440 and the electromagnetic brake actuators 464 and 466 involved in the embodiment.

[0042] Figure 34 This is a diagram that simulates the circuit configuration of the cut-off circuit 442 and the motor driver 462 involved in the embodiment.

[0043] Figure 35 This is a flowchart of the processes performed by the main MCU434 of the transport vehicle 2 involved in the embodiment.

[0044] Figure 36 This is a flowchart of the processing performed by the main MCU434 of the transport vehicle 2 in manual mode according to the embodiment.

[0045] Figure 37 This is a flowchart of the processing performed by the main MCU434 of the transport vehicle 2 in automatic mode according to the embodiment.

[0046] Figure 38 This is a flowchart of the processes performed by the motor MCU444 and 446 of the transport vehicle 2 involved in the embodiment.

[0047] Figure 39 This is a flowchart of the processes performed by the motor MCU444 and 446 of the transport vehicle 2 involved in the embodiment.

[0048] Figure 40 This is a flowchart of the processes performed by the motor MCU448 and 450 of the transport vehicle 2 involved in the embodiment.

[0049] Figure 41 This is a flowchart of the processes performed by the motor MCU448 and 450 of the transport vehicle 2 involved in the embodiment.

[0050] Figure 42 This is a graph showing the changes over time in the travel speed, braking current, and braking circuit temperature of the transport vehicle 2 involved in the embodiment when it is driven in manual mode on flat ground and downhill.

[0051] Figure 43 This is a flowchart of the process performed by the motor MCU452 of the transport vehicle 2 involved in the embodiment.

[0052] Explanation of reference numerals in the attached figures

[0053] 2: Transport vehicle; 4: Vehicle base unit; 6: Shelf unit; 8: Handle unit; 10: Steering unit; 11: Suspension mechanism; 12: Front wheel unit; 12a: Right front wheel unit; 12b: Left front wheel unit; 14: Rear wheel unit; 14a: Right rear wheel unit; 14b: Left rear wheel unit; 16: Bumper unit; 20: Base plate; 20a: Through hole; 20b: Through hole; 20c: Through hole; 20d: Through hole; 22: Front support component; 22a: Upper right connecting part; 22b: Lower right connecting part; 22c: Upper left connecting part; 22d: Lower left connecting part; 24: Rear support component; 26: Lower right frame; 28: Lower left frame; 30: Upper right frame; 32: Upper left frame. 34: Battery box; 36: Lower controller housing; 38: Battery pack; 40: Battery mounting section; 42: Battery cover; 44: Main control circuit board; 44a: Circuit board housing; 46: Drive control circuit board; 46a: Circuit board housing; 48: Drive control circuit board; 48a: Circuit board housing; 50: Electric brake circuit board; 50a: Heat sink housing; 50b: Circuit board storage section; 50c: Heat sink; 50d: Cooling fan; 52: Electric brake circuit board; 52a: Heat sink housing; 52b: Circuit board storage section; 52c: Heat sink; 52d: Cooling fan; 54: Electric brake circuit board; 54a: Heat sink housing; 54b: Circuit board storage section; 54c: 54d: Heat sink; 56: Cooling fan; 56: Electric brake circuit board; 56a: Heat sink housing; 56b: Circuit board storage part; 56c: Heat sink; 56d: Cooling fan; 58: Heat sink plate; 60: Main frame; 62: Right side guard; 64: Left side guard; 66: Front side guard; 70: Switch box; 72: Right side handlebar; 72a: Support part; 72b: Handlebar part; 72c: Right side gripping part; 73: Steering handlebar; 74: Left side handlebar; 74a: Support part; 74b: Handlebar part; 74c: Left side gripping part; 76: Handlebar robotic arm; 78: Support tube; 80: Clamping component; 80a: Clamping piece; 80b: Clamping piece; 80c: Fastening part; 82: Fixing component 84: Handlebar shaft; 84a: Guide protrusion; 86: Base component; 88: Rotation angle sensor; 90: Movable cam component; 90a: Cam convex part; 90b: Cam convex part; 90c: First cam surface; 90d: First cam surface; 90e: Second cam surface; 90f: Second cam surface; 90g: Guide groove; 90h: Spring receiving part; 92: Fixed cam component; 92a: Cylindrical part; 92b: Flange part; 92c: Cam recess; 92d: Cam recess; 92e: First cam surface; 92f: First cam surface; 92g: Second cam surface; 92h: Second cam surface; 92i: Stop part; 92j: Stop part; 94: Coil spring; 96: Main power switch; 98: Mode switching switch.98a: Grounding terminal; 98b: Manual mode terminal; 98c: Automatic mode terminal; 100: Trigger switch; 100a: Grounding terminal; 100b: Trigger terminal; 100c: Variable resistor; 102: Direction of travel switch; 102a: Grounding terminal; 102b: Direction of travel terminal; 104: Speed ​​switch; 106: Horn switch; 108: Handlebar unit; 126: Handlebar shaft; 136: Coil spring; 160: Motor housing; 162: Motor support component; 164: Gear housing; 166: Steering angle sensor; 168: Steering shaft; 168a: Gear section; 169: Transmission mechanism; 170: Steering plate; 172: Right connecting rod; 174: Left connecting rod. 176: Steering motor; 176a: Motor shaft; 176b: Gear section; 178: Main shaft; 178a: Spring support; 180: Cam; 180a: Cam groove; 181: Torque limiter; 182: Movable gear; 182a: Gear section; 182b: Recess; 182c: Cam protrusion; 184: Coil spring; 186: Cylindrical worm gear; 188: Worm gear; 190: Relay shaft; 190a: Gear section; 192: Right front wheel; 192a: Right front wheel axle; 194: Right gear housing; 195: Right retaining component; 196: Right motor housing; 198: Right pivot pin; 200: Right sleeve; 202: Upper right side arm; 204: Lower right side arm; 206: Right buffer component. 206a: Shock absorber; 206b: Coil spring; 208: Right steering plate; 212: Left front wheel; 212a: Left axle; 214: Left gear housing; 215: Left retaining component; 216: Left motor housing; 218: Left pivot pin; 220: Left sleeve; 222: Left upper arm; 224: Left lower arm; 226: Left buffer component; 226a: Shock absorber; 226b: Coil spring; 228: Left steering plate; 232: Right front wheel motor; 232a: Right front wheel motor shaft; 234: Planetary gear mechanism; 242: Left front wheel motor; 242a: Left front wheel motor shaft; 244: Planetary gear mechanism; 252: Right rear wheel; 254: Right gear housing; 254a: Connector Part 256: Right motor housing; 258: Right brake housing; 260: Right clutch lever; 264: Right buffer component; 264a: Shock absorber; 264b: Coil spring; 272: Left rear wheel; 274: Left gear housing; 274a: Connecting part; 276: Left motor housing; 278: Left brake housing; 280: Left clutch lever; 284: Left buffer component; 284a: Shock absorber; 284b: Coil spring; 302: Overload monitoring mechanism; 302a: Right front overload monitoring mechanism; 302b: Left front overload monitoring mechanism; 302c: Right rear overload monitoring mechanism; 302d: Left rear overload monitoring mechanism; 304: Emergency stop switch housing; 306: Upper controller housing.308: Emergency stop switch; 308a: Grounding terminal; 308b: Emergency stop terminal; 312: Upper controller housing; 312a: Columnar component; 312b: Columnar component; 312c: Columnar component; 312d: Columnar component; 314a: Helical spring; 314b: Helical spring; 314c: Helical spring; 314d: Helical spring; 316a: Monitoring board; 316b: Monitoring board; 316c: Monitoring board; 316d: Monitoring board; 318a: Base component; 318b: Base component; 318c: Base component; 318d: Base component; 320a: Overload monitoring sensor; 320b: Overload monitoring sensor; 320c: Overload monitoring sensor; 320d: Overload monitoring sensor Measurement sensor, 322a: cylindrical part, 322b: cylindrical part, 322c: cylindrical part, 322d: cylindrical part, 324a: flange part, 324b: flange part, 324c: flange part, 324d: flange part, 326a: upper small diameter part, 326b: upper small diameter part, 326c: upper small diameter part, 326d: upper small diameter part, 328a: lower small diameter part, 328b: lower small diameter part, 328c: lower small diameter part, 328d: lower small diameter part, 330a: through hole, 330b: through hole, 330c: through hole, 330d: through hole, 332a: threaded hole, 332b: threaded hole, 332c: threaded hole, 332d: threaded hole, 334a: washer, 334b 334c: Washer; 334d: Washer; 336a: Bolt; 336b: Bolt; 336c: Bolt; 336d: Bolt; 338a: Through hole; 338b: Through hole; 338c: Through hole; 338d: Through hole; 340a: Washer; 340b: Washer; 340c: Washer; 340d: Washer; 342a: Threaded hole; 342b: Threaded hole; 342c: Threaded hole; 342d: Threaded hole; 344a: Bolt; 344b: Bolt; 344c: Bolt; 344d: Bolt; 346a: Support; 346b: Support; 346c: Support; 346d: Support; 348a: Monitoring part; 348b: Monitoring part; 348c: Monitoring part Parts 348d: Monitoring part; 350a: Engaging part; 350b: Engaging part; 350c: Engaging part; 350d: Engaging part; 352a: Nut part; 352b: Nut part; 352c: Nut part; 352d: Nut part; 354a: Guide part; 354b: Guide part; 354c: Guide part; 354d: Guide part; 356a: Sensor holding part; 356b: Sensor holding part; 356c: Sensor holding part; 356d: Sensor holding part; 358a: Bolt; 358b: Bolt; 358c: Bolt; 358d: Bolt; 360a: Light-emitting element; 360b: Light-emitting element; 360c: Light-emitting element; 360d: Light-emitting element; 362a: Light-receiving element.362b: Light receiving element, 362c: Light receiving element, 362d: Light receiving element, 364: Overload monitoring mechanism, 366: Support component, 368: Columnar component, 370: Helical spring, 372: Monitoring plate, 374: Upper housing, 376: Sensor holding component, 378: Lower housing, 380: Overload monitoring sensor, 382: Cap, 384: Cylindrical part, 386: Upper small diameter part, 388: Lower small diameter part, 390: Through hole, 392: Threaded hole, 394: Washer, 396: Washer, 398: Bolt, 400: Reception chamber, 402: Bottom wall, 404: Through hole, 406: Sealing component, 408: Buffer component, 410: Threaded hole, 412: Bolt, 414 416: Support section; 418: Monitoring section; 420: Guiding section; 421: Light-emitting element; 422: Light-receiving element; 424: Storage space; 426: Automatic operation control circuit board; 428: Wireless I / F; 430: Automatic operation MCU; 432: Control power supply circuit; 434: Main MCU; 436: Switching circuit; 438: Cut-off circuit; 438a: Switching element; 438b: Driver IC; 438c: AND gate; 440: Cut-off circuit; 440a: Switching element; 440b: Driver IC; 440c: AND gate; 442: Cut-off circuit; 442a: Switching element; 442b: Driver IC; 442c: AND gate; 446: Motor MCU; 448: Motor MCU, 450: Motor MCU, 452: Motor MCU, 454: Motor Driver, 454a: First Switching Element, 454b: Second Switching Element, 454c: Third Switching Element, 454d: Fourth Switching Element, 454e: Fifth Switching Element, 454f: Sixth Switching Element, 454g: First Diode, 454h: Second Diode, 454i: Third Diode, 456: Motor Driver, 456a: First Switching Element, 456b: Second Switching Element, 456c: Third Switching Element, 456d: Fourth Switching Element, 456e: Fifth Switching Element, 456f: Sixth Switching Element, 456g: First Diode, 456h: Second Diode, 456 i: 3rd diode, 458: Motor driver, 458a: 1st switching element, 458b: 2nd switching element, 458c: 3rd switching element, 458d: 4th switching element, 458e: 5th switching element, 458f: 6th switching element, 458g: 1st diode, 458h: 2nd diode, 458i: 3rd diode, 460: Motor driver, 460a: 1st switching element, 460b: 2nd switching element, 460c: 3rd switching element, 460d: 4th switching element, 460e: 5th switching element, 460f: 6th switching element, 460g: 1st diode, 460h: 2nd diode, 460i: 3rd diode, 462: Motor driver,462a: First switching element, 462b: Second switching element, 462c: Third switching element, 462d: Fourth switching element, 462e: Fifth switching element, 462f: Sixth switching element, 464: Electromagnetic brake actuator, 464a: Switching element, 464b: Diode, 466: Electromagnetic brake actuator, 466a: Switching element, 466b: Diode, 468: Braking circuit, 468a: Switching element, 468b: Resistor, 468c: Amplifier, 468d: Operational amplifier, 468e: Thermistor, 470: Braking circuit, 470a: Switching element, 470b: Resistor, 470c: Amplifier, 470d: Operational amplifier, 470e: Thermistor, 47 2: Braking circuit; 472a: Switching element; 472b: Resistor; 472c: Amplifier; 472d: Operational amplifier; 472e: Thermistor; 474: Braking circuit; 474b: Resistor; 474c: Amplifier; 474d: Operational amplifier; 474e: Thermistor; 476: LED; 478: Buzzer; 480: Hall sensor; 482: Hall sensor; 484: Hall sensor; 486: Right rear wheel motor; 488: Hall sensor; 490: Right rear wheel electromagnetic brake; 492: Left rear wheel motor; 494: Hall sensor; 496: Left rear wheel electromagnetic brake; 500: Base component; 502: Housing; 502a: Storage part; 502b: Right side support part. 502c: Left support part, 504: Right headlight, 506: Left headlight, 508: Bumper frame, 510: Bumper support component, 512: Bumper support component, 514: Direct-acting tube, 514a: Elongated hole, 514b: Elongated hole, 516: Direct-acting tube, 516a: Elongated hole, 516b: Elongated hole, 518: Coil spring, 520: Coil spring, 522: Direct-acting bearing, 524: Direct-acting bearing, 526: Abutment plate, 526a: Abutment part, 528: Abutment plate, 528a: Abutment part, 530: Collision monitoring switch, 530a: Grounding terminal, 530b: Collision monitoring terminal, 532: Collision monitoring switch, 532a: Grounding terminal, 532b: Collision monitoring terminal, 5 34a: Bolt, 534b: Bolt, 536a: Nut, 536b: Nut, 538a: Bolt, 538b: Bolt, 540a: Nut, 540b: Nut, 542: Cancellation circuit, 542a: Transistor, 542b: Resistor, 542c: Resistor, 542d: Resistor, 544: Cancellation circuit, 544a: Transistor, 544b: Resistor, 544c: Resistor, 544d: Resistor, 546: Cancellation circuit, 546a: Transistor, 546b: Resistor, 546c: Resistor, 546d: Resistor, 548: Delay circuit, 548a: Diode, 548b: Resistor, 548c: Capacitor, 548d: Buffer gate, 550: AND gate, 552: AND gate554: OR gate, 556: OR gate, 558: NOT gate, 560: NOT gate, 562: NOT gate, 564: NOT gate, 566: NOT gate, 568: Resistor, 570: Resistor, 572: Resistor, 574: Resistor, 576: Resistor, 578: Resistor. Detailed Implementation

[0054] Hereinafter, with reference to the accompanying drawings, representative and non-limiting specific examples of the present invention will be described in detail. This detailed description is merely intended to show those skilled in the art the details of implementing preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Furthermore, in order to provide a further improved transport vehicle, its manufacturing method, and its method of use, the additional features and inventions disclosed below may differ from other features or inventions, or may be used in conjunction with them.

[0055] Furthermore, the features or combinations of processes disclosed in the following detailed description are not, in the broadest sense, essential components for carrying out the invention, but are merely descriptions for illustrating representative specific examples of the invention. Moreover, the various features of the representative specific examples described above and below, as well as the various features described in the independent and dependent claims, are not necessarily required to be combined as in the specific examples described herein, or in the order listed, when providing additional and useful embodiments of the invention.

[0056] All features described in this specification and / or the claims are intended to be disclosed separately and independently, as limitations on the specific matters claimed in the initial disclosure of the application, in addition to the features described in the embodiments and / or the claims. Furthermore, all descriptions relating to numerical ranges and groups or radicals are intended to disclose their intermediate configurations as limitations on the specific matters claimed in the initial disclosure of the application.

[0057] In one or more embodiments, the transport vehicle may include: a drive wheel; a motor that drives the drive wheel to rotate; a motor drive circuit configured to drive the motor; a control unit configured to control the motor by means of the motor drive circuit, such that the travel speed of the transport vehicle is below a maximum travel speed; and an operating component disposed on the transport vehicle for operation by a user. The transport vehicle can operate in a manual mode and an automatic mode. The manual mode is characterized by the motor being driven when the operating component is engaged and stopping when the operating component is disengaged. The automatic mode is characterized by the motor being driven regardless of whether the operating component is engaged or disengaged. The maximum travel speed in the automatic mode can be set to be lower than the maximum travel speed in the manual mode.

[0058] Based on the above configuration, since the upper limit of the transport vehicle's travel speed when operating in automatic mode is set to be lower than the upper limit of the transport vehicle's travel speed when operating in manual mode, the safety of the transport vehicle when operating in automatic mode can be further improved.

[0059] In one or more embodiments, the transport vehicle may further include an overload monitoring sensor for detecting overload of goods. In the automatic mode, when an overload is detected by the overload monitoring sensor, the movement of the transport vehicle can be prohibited. In the manual mode, the movement of the transport vehicle is permitted even if an overload is detected by the overload monitoring sensor.

[0060] Based on the above configuration, in manual mode, the transport vehicle is allowed to move even if an overload is detected, while in automatic mode, the transport vehicle is prohibited from moving when an overload is detected. Therefore, the safety of the transport vehicle when it operates in automatic mode can be further improved.

[0061] In one or more embodiments, the transport vehicle may further include a collision detection sensor for monitoring collisions with the transport vehicle from the front. In the automatic mode, when the transport vehicle is moving backward, if a collision is detected by the collision detection sensor, the movement of the transport vehicle can be prohibited. In the manual mode, even if a collision is detected by the collision detection sensor when the transport vehicle is moving backward, the movement of the transport vehicle can be permitted.

[0062] Based on the above configuration, in manual mode, the transport vehicle is allowed to move backward even if a collision from the front of the transport vehicle is detected. In automatic mode, the transport vehicle is prohibited from moving backward if a collision from the front of the transport vehicle is detected. Therefore, the safety of the transport vehicle when it operates in automatic mode can be improved.

[0063] In one or more embodiments, the transport vehicle may further include a collision detection sensor for monitoring collisions with other transport vehicles from behind. In the automatic mode, when the transport vehicle is moving forward, if a collision is detected by the collision detection sensor, the transport vehicle's movement can be prohibited. In the manual mode, even if a collision is detected by the collision detection sensor, the transport vehicle's movement can be permitted while it is moving forward.

[0064] Based on the above configuration, in manual mode, the transport vehicle is allowed to move forward even if a collision from behind is detected. In automatic mode, the transport vehicle is prohibited from moving forward if a collision from behind is detected. Therefore, the safety of the transport vehicle when it operates in automatic mode can be improved.

[0065] In one or more embodiments, the transport vehicle can perform, in the automatic mode, tracking operation that moves in accordance with a beacon carried by a user, and remote control operation that moves in accordance with instructions from a remote control operated by the user.

[0066] Based on the above configuration, the safety of the transport vehicle during automatic tracking and remote control operation can be further improved.

[0067] (Example)

[0068] Figure 1The transport vehicle 2 shown includes: a base unit 4, a rack unit 6, a handle unit 8, a steering unit 10, a front wheel unit 12, a rear wheel unit 14, and a bumper unit 16. The transport vehicle 2 is used to transport goods placed on the rack unit 6. The transport vehicle 2 includes a receiver (not shown) mounted on the base unit 4. The transport vehicle 2 can operate in manual, automatic, or parking modes. In manual mode, with a user standing behind the handle unit 8 and holding it, the transport vehicle 2 moves forward or backward according to the user's operation. In automatic mode, the transport vehicle 2 performs: tracking operation by moving in response to a beacon (not shown) carried by a user standing in front of the base unit 4, and remote control operation by moving according to instructions from a remote control (not shown) operated by the user. In this case, the transport vehicle 2 receives radio waves from the beacon or remote control via the receiver. In parking mode, the transport vehicle 2 locks the rear wheel unit 14 and remains stationary in the area.

[0069] (Vehicle base unit 4)

[0070] like Figure 2 , Figure 3 As shown, the vehicle base unit 4 includes: a base plate 20, a front support component 22, a rear support component 24, a lower right frame 26, a lower left frame 28, an upper right frame 30, an upper left frame 32, a battery box 34, an overload monitoring mechanism 302, an emergency stop switch housing 304, an upper controller housing 306, and a lower controller housing 36. The overload monitoring mechanism 302 includes: a front right overload monitoring mechanism 302a, a front left overload monitoring mechanism 302b, a rear right overload monitoring mechanism 302c, and a rear left overload monitoring mechanism 302d.

[0071] like Figure 2 As shown, the base plate 20 is an aluminum alloy component with a generally rectangular flat plate shape, with its long side along the front-to-back direction and its short side along the left-to-right direction. The emergency stop switch housing 304 is a resin component, fixed to the lower surface of the base plate 20 at its front end. An emergency stop switch 308, which can be pressed by a user, is provided on the front surface of the emergency stop switch housing 304. The emergency stop switch 308 is normally off and is turned on when pressed by a user. The emergency stop switch 308 is electrically connected to the main control circuit board 44, which will be described later. Alternatively, the emergency stop switch housing 304 can also be located at the rear, right, or left end of the base plate 20, and correspondingly, the emergency stop switch 308 can also be located on the rear, right, or left surface of the emergency stop switch housing 304.

[0072] The front support component 22 is a steel component, located at the front of the base plate 20, and is mounted on the lower surface of the base plate 20 via a right front overload monitoring mechanism 302a and a left front overload monitoring mechanism 302b. Figure 3 As shown, the rear support member 24 is a steel component, located at the rear of the base plate 20, and is mounted on the lower surface of the base plate 20 via the right rear overload monitoring mechanism 302c and the left rear overload monitoring mechanism 302d. The lower right frame 26 and the lower left frame 28 are both steel components, extending in the front-rear direction below the base plate 20. The front portions of the lower right frame 26 and the lower left frame 28 are respectively fixed to the front support member 22. The rear portions of the lower right frame 26 and the lower left frame 28 are respectively fixed to the rear support member 24.

[0073] The right front overload monitoring mechanism 302a, left front overload monitoring mechanism 302b, right rear overload monitoring mechanism 302c, and left rear overload monitoring mechanism 302d all have the same configuration. Figure 4 As shown, the right front overload monitoring mechanism 302a, left front overload monitoring mechanism 302b, right rear overload monitoring mechanism 302c, and left rear overload monitoring mechanism 302d each include: columnar components 312a, 312b, 312c, 312d; coil springs 314a, 314b, 314c, 314d; monitoring plates 316a, 316b, 316c, 316d; base components 318a, 318b, 318c, 318d; and overload monitoring sensors 320a, 320b, 320c, 320d. Figure 5As shown, the columnar components 312a, 312b, 312c, and 312d include: cylindrical portions 322a, 322b, 322c, and 322d; flange portions 324a, 324b, 324c, and 324d; upper small-diameter portions 326a, 326b, 326c, and 326d; and lower small-diameter portions 328a, 328b, 328c, and 328d. The cylindrical portions 322a, 322b, 322c, and 322d have a generally cylindrical shape along the vertical direction. The flange portions 324a, 324b, 324c, and 324d are disposed above the cylindrical portions 322a, 322b, 322c, and 322d, and have a shape that protrudes radially outward from the cylindrical portions 322a, 322b, 322c, and 322d. The upper small-diameter portions 326a, 326b, 326c, and 326d are disposed above the flange portions 324a, 324b, 324c, and 324d, and have a generally cylindrical shape with a diameter smaller than that of the cylindrical portions 322a, 322b, 322c, and 322d. The lower small-diameter portions 328a, 328b, 328c, and 328d are disposed below the cylindrical portions 322a, 322b, 322c, and 322d, and have a generally cylindrical shape with a diameter smaller than that of the cylindrical portions 322a, 322b, 322c, and 322d.

[0074] The upper small-diameter portions 326a, 326b, 326c, and 326d are inserted from below into the through holes 330a, 330b, 330c, and 330d formed in the base plate 20. Threaded holes 332a, 332b, 332c, and 332d are formed at the upper ends of the columnar components 312a, 312b, 312c, and 312d. Bolts 336a, 336b, 336c, and 336d are screwed into the threaded holes 332a, 332b, 332c, and 332d via washers 334a, 334b, 334c, and 334d. With bolts 336a, 336b, 336c, and 336d screwed into threaded holes 332a, 332b, 332c, and 332d, the base plate 20 is held by washers 334a, 334b, 334c, and 334d and flanges 324a, 324b, 324c, and 324d. Since the inner diameters of the through holes 20a, 20b, 20c, and 20d are slightly larger than the outer diameters of the upper smaller diameter portions 326a, 326b, 326c, and 326d, the columnar components 312a, 312b, 312c, and 312d can tilt slightly relative to the base plate 20.

[0075] The lower small-diameter portions 328a, 328b, 328c, and 328d are inserted from above into the through holes 338a, 338b, 338c, and 338d formed in the front support member 22 (or the rear support member 24). Since the inner diameter of the through holes 338a, 338b, 338c, and 338d is slightly larger than the outer diameter of the lower small-diameter portions 328a, 328b, 328c, and 328d, the columnar members 312a, 312b, 312c, and 312d can tilt slightly relative to the front support member 22 (or the rear support member 24). Helical springs 314a, 314b, 314c, and 314d are installed on the columnar members 312a, 312b, 312c, and 312d. The upper ends of the coil springs 314a, 314b, 314c, and 314d abut against the lower surfaces of the washers 340a, 340b, 340c, and 340d. The upper surfaces of the washers 340a, 340b, 340c, and 340d abut against the lower surfaces of the flanges 324a, 324b, 324c, and 324d. The lower ends of the coil springs 314a, 314b, 314c, and 314d abut against the upper surface of the front support member 22 (or the rear support member 24). The coil springs 314a, 314b, 314c, and 314d exert an upward force on the columnar members 312a, 312b, 312c, and 312d relative to the front support member 22 (or the rear support member 24).

[0076] Threaded holes 342a, 342b, 342c, and 342d are formed at the lower ends of columnar components 312a, 312b, 312c, and 312d. Bolts 344a, 344b, 344c, and 344d are screwed into the threaded holes 342a, 342b, 342c, and 342d via monitoring plates 316a, 316b, 316c, and 316d. Monitoring plates 316a, 316b, 316c, and 316d include: support portions 346a, 346b, 346c, and 346d, which have a generally flat plate shape along the front-back direction and the left-right direction; and monitoring portions 348a, 348b, 348c, and 348d, which are bent downward from the ends of support portions 346a, 346b, 346c, and 346d, and have a generally flat plate shape along the front-back direction and the up-down direction.

[0077] The base components 318a, 318b, 318c, and 318d include: engaging portions 350a, 350b, 350c, and 350d; nut portions 352a, 352b, 352c, and 352d; guide portions 354a, 354b, 354c, and 354d; and sensor holding portions 356a, 356b, 356c, and 356d. The engaging portions 350a, 350b, 350c, and 350d can engage with the front support component 22 (or the rear support component 24). Bolts 358a, 358b, 358c, and 358d are screwed into the nut portions 352a, 352b, 352c, and 352d. The lower ends of bolts 358a, 358b, 358c, and 358d pass through nut portions 352a, 352b, 352c, and 352d, and abut against the upper surface of the front support member 22 (or the rear support member 24). With the engaging portions 350a, 350b, 350c, and 350d engaged with the front support member 22 (or the rear support member 24), bolts 358a, 358b, 358c, and 358d are tightened relative to nut portions 352a, 352b, 352c, and 352d, thereby fixing base members 318a, 318b, 318c, and 318d to the front support member 22 (or the rear support member 24). The guide units 354a, 354b, 354c, and 354d are shaped to guide the vertical movement of the monitoring plates 316a, 316b, 316c, and 316d. Overload monitoring sensors 320a, 320b, 320c, and 320d are mounted on the sensor holding units 356a, 356b, 356c, and 356d. The vertical mounting position of the overload monitoring sensors 320a, 320b, 320c, and 320d relative to the sensor holding units 356a, 356b, 356c, and 356d is adjustable.

[0078] The overload monitoring sensors 320a, 320b, 320c, and 320d in this embodiment are so-called optocouplers. The overload monitoring sensors 320a, 320b, 320c, and 320d include light-emitting elements 360a, 360b, 360c, and 360d arranged opposite each other, and light-receiving elements 362a, 362b, 362c, and 362d. The overload monitoring sensors 320a, 320b, 320c, and 320d are disconnected when there is no obstruction between the light-emitting elements 360a, 360b, 360c, and 360d and the light-receiving elements 362a, 362b, 362c, and 362d, and are connected when there is obstruction between the light-emitting elements 360a, 360b, 360c, and 360d and the light-receiving elements 362a, 362b, 362c, and 362d. Overload monitoring sensors 320a, 320b, 320c, and 320d are electrically connected to the main control circuit board 44, which will be described later (see reference). Figure 9 ).

[0079] like Figure 5 As shown, when there are no goods on the shelf unit 6 and no load from the shelf unit 6 acts on the base plate 20, the upper surfaces of the support portions 346a, 346b, 346c, and 346d of the monitoring plates 316a, 316b, 316c, and 316d abut against the lower surface of the front support member 22 (or the rear support member 24) through the force of the coil springs 314a, 314b, 314c, and 314d. In this state, the monitoring units 348a, 348b, 348c, and 348d of the monitoring boards 316a, 316b, 316c, and 316d do not block the light-emitting elements 360a, 360b, 360c, and 360d from the light-receiving elements 362a, 362b, 362c, and 362d. Therefore, the overload monitoring sensors 320a, 320b, 320c, and 320d are disconnected.

[0080] from Figure 5 In the indicated state, goods are placed on rack unit 6. When the load from rack unit 6 acts on base plate 20, columnar members 312a, 312b, 312c, 312d and monitoring plates 316a, 316b, 316c, 316d overcome the force of coil springs 314a, 314b, 314c, 314d and move downward relative to front support member 22 (or rear support member 24). At this time, when a load exceeding the specified upper limit load (e.g., 25 kgf) acts on columnar members 312a, 312b, 312c, 312d, as... Figure 6 As shown, monitoring plates 316a, 316b, 316c, and 316d will block the light-emitting elements 360a, 360b, 360c, and 360d from the light-receiving elements 362a, 362b, 362c, and 362d, causing the overload monitoring sensors 320a, 320b, 320c, and 320d to switch from off to on. Furthermore, until the lower surfaces of the cylindrical portions 322a, 322b, 322c, and 322d abut against the upper surface of the base plate 20, the columnar members 312a, 312b, 312c, and 312d, along with the monitoring plates 316a, 316b, 316c, and 316d, can move downwards relative to the base plate 20. With this configuration, the overload monitoring mechanism 302 can monitor the overload of the shelf unit 6. For example, when the upper limit load of each of the right front overload monitoring mechanism 302a, left front overload monitoring mechanism 302b, right rear overload monitoring mechanism 302c, and left rear overload monitoring mechanism 302d is 25 kgf, the overload monitoring mechanism 302 detects the overload of the rack unit 6 when the rack unit 6 is loaded with more than 100 kg of goods.

[0081] As described above, overload monitoring sensors 320a, 320b, 320c, and 320d are all non-contact monitoring sensors. Therefore, it is possible to suppress the transmission of vibration or impact from the shelving unit 6 to the overload monitoring sensors 320a, 320b, 320c, and 320d, thereby preventing the overload monitoring sensors 320a, 320b, 320c, and 320d from malfunctioning.

[0082] Additionally, the right front overload monitoring mechanism 302a, left front overload monitoring mechanism 302b, right rear overload monitoring mechanism 302c, and left rear overload monitoring mechanism 302d can also be used. Figure 7 The overload monitoring mechanism 364 shown is as follows. The overload monitoring mechanism 364 includes: a support member 366, a columnar member 368, a coil spring 370, a monitoring plate 372, an upper housing 374, a sensor holding member 376, a lower housing 378, an overload monitoring sensor 380, and a cap 382.

[0083] Support member 366 is fixed to the lower surface of base plate 20. Columnar member 368 includes a cylindrical portion 384, an upper small-diameter portion 386, and a lower small-diameter portion 388. The cylindrical portion 384 has a generally cylindrical shape along its vertical axis. The upper small-diameter portion 386 is positioned above the cylindrical portion 384 and has a generally cylindrical shape with a diameter smaller than that of the cylindrical portion 384. The lower small-diameter portion 388 is positioned below the cylindrical portion 384 and has a generally cylindrical shape with a diameter smaller than that of the cylindrical portion 384. The upper small-diameter portion 386 is inserted from below into a through hole 390 formed in support member 366. A threaded hole 392 is formed at the upper end of columnar member 368. Bolt 398 is screwed into threaded hole 392 via washers 394 and 396. With the bolt 398 screwed into the threaded hole 392, the support member 366 is held between the washer 396 and the cylindrical portion 384. Since the inner diameter of the through hole 390 is slightly larger than the outer diameter of the upper small diameter portion 386, the cylindrical member 368 can tilt slightly relative to the support member 366.

[0084] The lower small-diameter portion 388 and the cylindrical portion 384 are inserted from above into the storage chamber 400 formed in the upper outer casing 374. The lower small-diameter portion 388 is inserted from above into the through hole 404 formed in the bottom wall 402 of the storage chamber 400. The inner diameter of the through hole 404 is slightly larger than the outer diameter of the lower small-diameter portion 388, so the cylindrical member 368 can tilt slightly relative to the upper outer casing 374. A coil spring 370 is installed on the cylindrical member 368. The upper end of the coil spring 370 abuts against the lower surface of the cylindrical portion 384. The lower end of the coil spring 370 abuts against the upper surface of the bottom wall 402. The coil spring 370 applies an upward force to the cylindrical member 368 relative to the upper outer casing 374. The inner diameter of the storage chamber 400 is slightly larger than the outer diameter of the cylindrical portion 384. A sealing member 406 is provided near the upper end of the storage chamber 400, which can slide against the side of the cylindrical portion 384. The sealing member 406 is, for example, a resin O-ring. The sealing member 406 can prevent foreign objects from entering the interior of the storage chamber 400. In addition, a ring-shaped buffer member 408 is provided at the upper end of the upper outer casing 374.

[0085] A threaded hole 410 is formed at the lower end of the columnar member 368. A bolt 412 is screwed into the threaded hole 410 via a monitoring plate 372. The monitoring plate 372 includes: a support portion 414 having a generally flat shape along the front-rear and left-right directions; and a monitoring portion 416 that bends downward from the end of the support portion 414 and has a generally flat shape along the front-rear and up-down directions. A guide portion 418 is formed at the lower part of the upper housing 374 to guide the up-down movement of the monitoring plate 372.

[0086] A sensor holding member 376 is fixed to the lower end of the upper housing 374. An overload monitoring sensor 380 is mounted on the sensor holding member 376. In this embodiment, the overload monitoring sensor 380 is a so-called optocoupler. The overload monitoring sensor 380 includes a light-emitting element 420 and a light-receiving element 422 arranged opposite to each other. The overload monitoring sensor 380 is disconnected when there is no obstruction between the light-emitting element 420 and the light-receiving element 422, and is connected when there is obstruction between the light-emitting element 420 and the light-receiving element 422. The overload monitoring sensor 380 is connected to the main control circuit board 44 described later (see reference). Figure 9 Electrical connection.

[0087] A storage space 424 is formed in the lower outer casing 378, extending from top to bottom. The lower part of the upper outer casing 374 is inserted into the storage space 424 of the lower outer casing 378 from top to bottom. The monitoring plate 372, the sensor holding member 376, and the overload monitoring sensor 380 are housed within the storage space 424. The lower outer casing 378 and the upper outer casing 374 are fixed together to the front support member 22 (or the rear support member 24). A cap 382 is detachably installed at the lower end of the lower outer casing 378.

[0088] like Figure 7 As shown, when there are no goods placed on the shelf unit 6 and no load from the shelf unit 6 acts on the base plate 20, the upper surface of the support portion 414 of the monitoring plate 372 abuts against the lower surface of the bottom wall 402 of the upper outer casing 374 due to the force of the coil spring 370. In this state, the monitoring portion 416 of the monitoring plate 372 does not block the light-emitting element 420 and the light-receiving element 422, therefore, the overload monitoring sensor 380 is disconnected.

[0089] from Figure 7 In the indicated state, goods are placed on rack unit 6. When the load from rack unit 6 acts on base plate 20, column member 368 and monitoring plate 372 move downward relative to upper housing 374 against the force of coil spring 370. At this time, when a load exceeding the specified upper limit load (e.g., 25 kgf) acts on column member 368, such as... Figure 8 As shown, the monitoring plate 372 blocks the light-emitting element 420 and the light-receiving element 422, and the overload monitoring sensor 380 switches from off to on. Furthermore, both the columnar member 368 and the monitoring plate 372 can move downwards relative to the base plate 20 until the lower surface of the support member 366 abuts against the upper surface of the buffer member 408. With this configuration, the overload monitoring mechanism 302 can monitor the overload of the shelf unit 6.

[0090] As described above, the overload monitoring sensor 380 is a non-contact monitoring sensor. Therefore, it is possible to prevent vibrations or impacts from the shelving unit 6 from being transmitted to the overload monitoring sensor 380, thereby preventing the overload monitoring sensor 380 from malfunctioning.

[0091] For the overload monitoring mechanism 302, the coil spring 370, the monitoring plate 372, and the overload monitoring sensor 380 are surrounded by the upper housing 374, the lower housing 378, and the cap 382. By adopting this configuration, it is possible to prevent foreign objects from adhering to the coil spring 370, the monitoring plate 372, the overload monitoring sensor 380, etc., and affecting the operation of the overload monitoring mechanism 302.

[0092] like Figure 3 As shown, the upper right frame 30 and the upper left frame 32 are both made of aluminum alloy and extend along the front-to-back direction, positioned above the base plate 20. The upper right frame 30 and the upper left frame 32 are respectively fixed to the upper surface of the base plate 20. The upper controller housing 312 is a resin component and is fixed to the upper surface of the base plate 20 between the upper right frame 30 and the upper left frame 32. Figure 9 As shown, an automatic operation control circuit board 426 is housed inside the upper controller housing 312. The automatic operation control circuit board 426 is equipped with a wireless interface (hereinafter referred to as I / F) 428 (see reference 428) that is electrically connected to a receiver mounted on the vehicle base unit 4. Figure 30 ), and an automatic operation microcontroller unit (hereinafter referred to as MCU) 430 electrically connected to the wireless I / F428 (see reference). Figure 30 The automatic operation control circuit board 426 is electrically connected to the main control circuit board 44, which will be described later.

[0093] like Figure 3 As shown, the battery box 34 is a resin component, located near the rear of the base plate 20, positioned slightly below it. The battery box 34 is fixed to the rear support member 24. Figure 9 As shown, a battery mounting section 40 is provided inside the battery box 34, allowing for the installation and removal of a battery pack 38. The battery pack 38 includes secondary battery cells, such as lithium-ion battery cells. The transport vehicle 2 operates by being powered by the battery pack 38 installed in the battery mounting section 40. A closable battery cover 42 is provided at the rear of the battery box 34. With the battery cover 42 open, the battery pack 38 can slide relative to the battery mounting section 40 in the front-to-back direction, thereby allowing the battery pack 38 to be installed and removed from the battery mounting section 40.

[0094] like Figure 2 As shown, the lower controller housing 36 is a resin component, located near the center of the base plate 20, and positioned below the base plate 20. The lower controller housing 36 is fixed to the lower right frame 26 and the lower left frame 28 while being placed on the upper surfaces of the lower right frame 26 and the lower left frame 28. Figure 9 , Figure 10 As shown, the lower controller housing 36 holds one main control circuit board 44, two drive control circuit boards 46 and 48, and four electric braking circuit boards 50, 52, 54, and 56.

[0095] like Figure 9As shown, the main control circuit board 44 is housed inside the circuit board housing 44a. The circuit board housing 44a is housed behind the lower controller housing 36. The circuit board housing 44a is configured such that the main control circuit board 44 extends along both the vertical and horizontal directions. The main control circuit board 44 houses the following components: a control power supply circuit 432, a main MCU 434, a switching circuit 436, and cut-off circuits 438, 440, and 442 (see reference). Figure 30 )wait.

[0096] like Figure 10 As shown, the drive control circuit boards 46 and 48 are respectively housed inside the circuit board housings 46a and 48a. Figure 9 As shown, circuit board housings 46a and 48a are housed inside the lower controller housing 36 at its lower front. The circuit board housings 46a and 48a are configured such that the drive control circuit boards 46 and 48 are positioned along both the front-to-back and left-to-right directions. The drive control circuit boards 46 and 48 are electrically connected to the main control circuit board 44. The drive control circuit board 46 houses the following components: motor MCUs 444, 448, and 452 (described later), motor drivers 454, 458, and 462, and an electromagnetic brake driver 464 (see reference). Figure 30 The drive control circuit board 48 includes: motor MCUs 446 and 450 (described later), motor drivers 456 and 460, and electromagnetic brake driver 466 (see reference). Figure 30 )wait.

[0097] like Figure 10As shown, electric braking circuit boards 50, 52, 54, and 56 are respectively mounted on heat sink housings 50a, 52a, 54a, and 56a. Heat sink housings 50a, 52a, 54a, and 56a include: circuit board housing portions 50b, 52b, 54b, and 56b for housing the electric braking circuit boards 50, 52, 54, and 56 respectively; heat sinks 50c, 52c, 54c, and 56c; and cooling fans 50d, 52d, 54d, and 56d. Heat sink housings 50a and 52a are housed inside the lower controller housing 36 at its upper front. The heat sink housings 50a and 52a are configured such that the electric braking circuit boards 50 and 52 are positioned along the front-rear and left-right directions, and the cooling fans 50d and 52d face upwards. Heat sink housings 54a and 56a are fixed to a heat sink plate 58 of the lower controller housing 36 located at its lower front exterior. Heat sink housings 54a and 56a are configured such that the electric braking circuit boards 54 and 56 are positioned along the front-to-back and left-to-right directions, and the cooling fans 54d and 56d face downwards. The electric braking circuit boards 50 and 54, along with the cooling fans 50d and 54d, are electrically connected to the drive control circuit board 46. The electric braking circuit boards 52 and 56, along with the cooling fans 52d and 56d, are electrically connected to the drive control circuit board 48. The electric braking circuit boards 50, 52, 54, and 56 are respectively equipped with braking circuits 468, 470, 472, and 474 (described later) (see reference). Figure 30 )wait.

[0098] (Shelf Unit 6)

[0099] like Figure 1 As shown, the rack unit 6 includes: a main frame 60, a right-side guard 62, a left-side guard 64, and a front-side guard 66. The main frame 60, right-side guard 62, left-side guard 64, and front-side guard 66 are all constructed of steel round tubes. The main frame 60 is positioned above the base plate 20 of the platform unit 4, arranged along both the front-rear and rear-rear directions. The main frame 60 is fixed to the upper right and upper left side frames 30 and 32 of the platform unit 4 while being placed on their upper surfaces. Goods transported by the transport vehicle 2 are placed on the upper surface of the main frame 60. The right-side guard 62 is installed at the right end of the main frame 60, protruding upwards from its upper surface. The right-side guard 62 is arranged along both the front-rear and rear-rear directions. The left-side guard 64 is installed at the left end of the main frame 60, protruding upwards from its upper surface. The left protective member 64 is configured to extend along both the front-to-back and vertical directions. The front protective member 66 is mounted to the front end of the main frame 60 in a manner that protrudes upward beyond the upper surface of the main frame 60. The front protective member 66 is configured to extend along both the left-to-right and vertical directions.

[0100] (Handlebar Unit 8)

[0101] like Figure 11 As shown, the handlebar unit 8 includes: a switch box 70, a right handlebar 72, a left handlebar 74, a handlebar robotic arm 76, a support tube 78, a clamping component 80, a fixing component 82, a handlebar shaft 84, a base component 86, a rotation angle sensor 88, a movable cam component 90, a fixed cam component 92, and a coil spring 94. Hereinafter, the right handlebar 72, the left handlebar 74, the handlebar robotic arm 76, and the support tube 78 will be collectively referred to as the steering handlebar 73.

[0102] The switch box 70 includes: a main power switch 96, a mode switching switch 98, a trigger switch 100, a travel direction switching switch 102, a speed switching switch 104, a horn switch 106, and an LED 476. The main power switch 96 switches the main power supply of the transport vehicle 2 on / off. The mode switching switch 98 switches the operating mode of the transport vehicle 2 between manual, automatic, and stop modes. In manual mode, the trigger switch 100 switches the forward or backward movement of the transport vehicle 2, or adjusts its travel speed. The travel direction switching switch 102 switches the travel direction of the transport vehicle 2 in manual mode. The speed switching switch 104 switches the maximum travel speed of the transport vehicle 2 in manual mode. The horn switch 106 uses a buzzer 478 (see reference) built into the switch box 70. Figure 30 It can sound the horn. LED476 can display: the on / off state of the main power supply of the transport vehicle 2, the set direction of travel, or the maximum travel speed. The main power switch 96, mode switch 98, trigger switch 100, direction of travel switch 102, speed switch 104, horn switch 106, LED476, and buzzer 478 are respectively connected to the main control circuit board 44 (see reference). Figure 9 Electrical connection.

[0103] The right handlebar 72 includes a support portion 72a extending vertically and a handlebar portion 72b curving to the right from the upper end of the support portion 72a. The lower end of the support portion 72a is fixed to the handlebar mechanical arm 76. A right-side grip portion 72c is provided at the right end of the handlebar portion 72b. The switch box 70 is fixed to the handlebar portion 72b at a position to the left of the right-side grip portion 72c. The left handlebar 74 includes a support portion 74a extending vertically and a handlebar portion 74b curving to the left from the upper end of the support portion 74a. The lower end of the support portion 74a is fixed to the handlebar mechanical arm 76. A left-side grip portion 74c is provided at the left end of the handlebar portion 74b. The upper end of a support tube 78 is fixed to the handlebar mechanical arm 76. The support tube 78 extends vertically. The clamping member 80 includes clamping plates 80a and 80b that clamp the support tube 78 from the left and right sides. A fastening portion 80c is formed at the rear end of the clamping pieces 80a and 80b, which is fastened by a fastener (not shown). When the fastener of the fastening portion 80c is tightened, the clamping pieces 80a and 80b are pressed forcefully against the outer surface of the support tube 78, thereby fixing the support tube 78 to the clamping member 80. When the fastener of the fastening portion 80c is loosened, the clamping pieces 80a and 80b are not pressed against the outer surface of the support tube 78, and the support tube 78 can move vertically relative to the clamping member 80 and can rotate about vertically. With the fastener of the fastening portion 80c loosened, after adjusting the support tube 78 relative to the clamping member 80 to the desired position and angle, the fastener of the fastening portion 80c is tightened, thereby fixing the position and angle of the support tube 78 relative to the clamping member 80.

[0104] like Figure 12 As shown, the front of the clamping member 80 is fixed to the fixing member 82. The upper end of the handlebar shaft 84 is fixed to the fixing member 82. The lower end of the handlebar shaft 84 is rotatably supported on the base member 86. The base member 86 is fixed to the upper surface of the base plate 20 of the vehicle base unit 4. A rotation angle sensor 88 is fixed to the lower part of the base member 86. The rotation angle sensor 88 is connected to the lower end of the handlebar shaft 84. The rotation angle sensor 88 detects the rotation angle of the handlebar shaft 84 relative to the base member 86. The rotation angle sensor 88 may be, for example, a potentiometer that detects the change in electrical resistance value corresponding to the change in rotation angle. Alternatively, the rotation angle sensor 88 may be a magnetic rotation sensor having a Hall element fixed in position relative to the base member 86 and a permanent magnet fixed in position relative to the handlebar shaft 84. The rotation angle sensor 88 and the main control circuit board 44 (see reference) Figure 9 Electrical connection.

[0105] like Figure 13As shown, a guide protrusion 84a is provided on the handlebar shaft 84. The guide protrusion 84a protrudes radially outward from the outer peripheral surface of the handlebar shaft 84 and extends along the axial direction of the handlebar shaft 84.

[0106] like Figure 14 As shown, the movable cam member 90 has a generally cylindrical shape. Cam protrusions 90a and 90b extending downwards are formed at the lower part of the movable cam member 90. First cam surfaces 90c and 90d, and second cam surfaces 90e and 90f are respectively provided on the cam protrusions 90a and 90b. When viewed from above, the first cam surfaces 90c and 90d are inclined from bottom to top in a clockwise direction. When viewed from above, the second cam surfaces 90e and 90f are inclined from bottom to top in a counterclockwise direction. A guide groove 90g is formed on the inner circumferential surface of the movable cam member 90. The guide groove 90g has: a guide protrusion 84a (see reference...) Figure 13 The movable cam member 90 has a corresponding width and extends along the central axis of the movable cam member 90. When the movable cam member 90 is mounted on the handlebar shaft 84, the guide protrusion 84a engages with the guide groove 90g in a manner that allows it to slide in the vertical direction. Therefore, the movable cam member 90 is held on the handlebar shaft 84 in a manner that allows it to move in the vertical direction. A spring receiving portion 90h is formed on the upper part of the movable cam member 90 to support the coil spring 94. Figure 12 As shown, the helical spring 94 exerts a downward force on the movable cam component 90 relative to the fixed component 82.

[0107] like Figure 15 As shown, the fixed cam member 92 includes a generally cylindrical portion 92a and a flange portion 92b extending radially outward from the lower end of the cylindrical portion 92a. The flange portion 92b is fastened to the base member 86 (see reference 86) by a fastener (not shown). Figure 12 The upper surface of the cylindrical portion 92a is such that the fixed cam member 92 is fixed to the base member 86. Cam recesses 92c and 92d, corresponding to the cam protrusions 90a and 90b of the movable cam member 90, are formed on the upper part of the cylindrical portion 92a. First cam surfaces 92e and 92f, and second cam surfaces 92g and 92h are respectively provided in the cam recesses 92c and 92d. The first cam surfaces 92e and 92f correspond to the first cam surfaces 90c and 90d of the movable cam member 90, respectively. The second cam surfaces 92g and 92h correspond to the second cam surfaces 90e and 90f of the movable cam member 90, respectively. Additionally, stop portions 92i and 92j are provided on the inner circumferential surface of the cylindrical portion 92a. Figure 16As shown, when the handlebar shaft 84 rotates relative to the fixed cam member 92, the stop parts 92i and 92j limit the rotation range of the handlebar shaft 84 by abutting against the guide protrusion 84a of the handlebar shaft 84.

[0108] exist Figure 11 The handlebar unit 8 shown rotates in the same direction (clockwise or counterclockwise) when the user rotates the steering handlebar 73 clockwise as viewed from above. At this time, as... Figure 17 As shown, the movable cam component 90 rotates integrally with the handlebar shaft 84. Consequently, the first cam surfaces 90c and 90d (or the second cam surfaces 90e and 90f) of the movable cam component 90 slide relative to the first cam surfaces 92e and 92f (or the second cam surfaces 92g and 92h) of the fixed cam component 92. While rotating relative to the fixed cam component 92, the movable cam component 90 moves upward against the force of the coil spring 94. At this time, the torque generated by the reverse force received by the movable cam component 90 from the fixed cam component 92 acts on the user who rotates the steering handlebar 73.

[0109] (Steering Unit 10)

[0110] like Figure 18 As shown, the steering unit 10 is mounted on the base plate 20 of the vehicle base unit 4 (refer to...). Figure 2 The front support component 22 is mounted on the lower front part of the front wheel unit 12. The steering unit 10 is connected to the front wheel unit 12 and performs steering for the front wheel unit 12.

[0111] like Figure 19 As shown, the steering unit 10 includes: a motor housing 160, a motor support member 162, a gear housing 164, a steering angle sensor 166, a steering shaft 168, a steering plate 170, a right-side connecting rod 172, and a left-side connecting rod 174. The motor housing 160 is fixed to the motor support member 162. The motor support member 162 is fixed to the gear housing 164. The gear housing 164 is fixed to the front support member 22 of the vehicle base unit 4 (see reference). Figure 18 ).

[0112] like Figure 20 As shown, a steering motor 176 is housed inside the motor housing 160. The steering motor 176 is, for example, an internal rotor type brushless DC motor. The steering motor 176 and the drive control circuit board 46 (see reference) Figure 10 Electrical connection. The steering motor 176 includes: a motor shaft 176a extending in the forward and backward direction, and a Hall sensor 480 for detecting the rotation of the motor shaft 176a (see reference). Figure 34The motor shaft 176a is rotatably held in the motor housing 160 near its rear end, and rotatably held in the motor support member 162 at its front end. The front portion of the motor shaft 176a passes through the motor support member 162 and enters the interior of the gear housing 164. A gear portion 176b is formed near the front end of the motor shaft 176a.

[0113] The gear housing 164 houses: a main shaft 178, a cam 180, a movable gear 182, a coil spring 184, a cylindrical worm gear 186, a worm wheel 188, and a relay shaft 190. The main shaft 178 is configured to run in the front-to-back direction. The main shaft 178 is rotatably held in the gear housing 164 near its front end and rear end. Additionally, the main shaft 178 is rotatably held in the motor support member 162 near its rear end.

[0114] Cam 180 is fixed near the rear end of spindle 178. For example... Figure 21 As shown, a cam groove 180a is formed on the front surface of the cam 180. A movable gear 182 is mounted on the main shaft 178 at a position forward of the cam 180. The movable gear 182 is movable relative to the main shaft 178 in the front-rear direction and is held on the main shaft 178 in a manner that allows it to rotate about the front-rear direction. A gear portion 176b (see reference) is formed on the outer peripheral surface of the movable gear 182, corresponding to the motor shaft 176a. Figure 20 The movable gear 182a engages with the gear. A recess 182b is formed at the rear of the movable gear 182, into which the cam 180 enters. A cam protrusion 182c corresponding to the cam groove 180a of the cam 180 is formed in the recess 182b. A coil spring 184 is mounted on the main shaft 178 at a position forward of the movable gear 182. The coil spring 184 is held in a spring receiving portion 178a provided on the main shaft 178. The coil spring 184 applies a rearward force to the movable gear 182 relative to the main shaft 178.

[0115] When motor shaft 176a (refer to) Figure 20When the main shaft 178 rotates, the movable gear 182 also rotates. With the cam protrusion 182c of the movable gear 182 engaged with the cam groove 180a of the cam 180, the cam 180 rotates along with the rotation of the movable gear 182, and consequently, the main shaft 178 also rotates. When the torque acting between the movable gear 182 and the cam 180 is small, the engagement of the cam protrusion 182c with the cam groove 180a is maintained by the force of the coil spring 184, thereby maintaining the rotation transmitted from the motor shaft 176a to the main shaft 178. Conversely, when the torque acting between the movable gear 182 and the cam 180 is large, the movable gear 182 moves forward against the force of the coil spring 184, the engagement of the cam protrusion 182c with the cam groove 180a is released, and the rotation transmitted from the motor shaft 176a to the main shaft 178 is interrupted. That is, the torque limiter 181 is composed of cam 180, movable gear 182, and helical spring 184.

[0116] like Figure 20 As shown, the cylindrical worm gear 186 is fixed to the front of the main shaft 178. The worm wheel 188 is configured to mesh with the cylindrical worm gear 186. Figure 22 As shown, the worm gear 188 is fixed to the upper part of the relay shaft 190. The relay shaft 190 is configured to run vertically. The relay shaft 190 is rotatably held in the gear housing 164 near its upper end and in its central portion. A gear portion 190a is formed near the lower end of the relay shaft 190.

[0117] A steering angle sensor 166 is fixed to the upper part of the gear housing 164. The steering angle sensor 166 is connected to the upper end of the relay shaft 190. The steering angle sensor 166 detects the rotation angle of the relay shaft 190 relative to the gear housing 164. The steering angle sensor 166 may be, for example, a potentiometer that detects the change in resistance value corresponding to the change in rotation angle. Alternatively, the steering angle sensor 166 may be a magnetic rotation sensor having a Hall element fixed relative to the gear housing 164 and a permanent magnet fixed relative to the relay shaft 190. The steering angle sensor 166 and the main control circuit board 44 (see reference) Figure 9 Electrical connection.

[0118] The steering shaft 168 is rotatably held in the gear housing 164 near its upper end and at its upper portion. The steering shaft 168 is configured to run vertically. A gear portion 168a is formed on the upper portion of the steering shaft 168, meshing with a gear portion 190a of the relay shaft 190. The lower end of the steering shaft 168 is fixed near the front end of the steering plate 170. Figure 19As shown, the steering plate 170 has an elongated flat plate shape with its long side in the front-to-back direction and its short side in the left-to-right direction. Near the rear end of the steering plate 170, the rear ends of the right connecting rod 172 and the left connecting rod 174 are connected. The rear end of the right connecting rod 172 is connected to the steering plate 170 in a manner that allows it to rotate about two axes orthogonal to the long side of the right connecting rod 172. The rear end of the left connecting rod 174 is connected to the steering plate 170 in a manner that allows it to rotate about two axes orthogonal to the long side of the left connecting rod 174.

[0119] like Figure 20 As shown, when the main shaft 178 rotates due to the rotation of the motor shaft 176a, the rotation of the main shaft 178 is transmitted to the relay shaft 190 via the cylindrical worm gear 186 and the worm wheel 188. Figure 22 As shown, when the relay shaft 190 rotates, the steering shaft 168 rotates simultaneously, and the rear end of the steering plate 170 rotates to the left and right. Through the rotation of the steering plate 170, Figure 19 The right connecting rod 172 and the left connecting rod 174 shown are moved to steer the front wheel unit 12. Furthermore, in the following description, the steering shaft 168, steering plate 170, right connecting rod 172, left connecting rod 174, main shaft 178, torque limiter 181, cylindrical worm gear 186, worm wheel 188, and relay shaft 190 are collectively referred to as the transmission mechanism 169.

[0120] Main control circuit board 44 (reference) Figure 9 In manual mode, based on the data from handlebar unit 8 (reference 8) Figure 11 The steering angle that should be achieved in the steering unit 10 is calculated based on the detection signal of the rotation angle sensor 88. Furthermore, the main control circuit board 44 calculates the rotation angle that should be achieved by the steering motor 176 based on the steering angle that should be achieved in the steering unit 10, and sends an instruction to the drive control circuit board 46 to drive the steering motor 176. Accordingly, the steering unit 10 achieves a steering angle corresponding to the operation performed by the user in the handlebar unit 8.

[0121] (Front wheel unit 12)

[0122] like Figure 18 As shown, the front wheel unit 12 is on the base plate 20 of the vehicle base unit 4 (refer to...). Figure 2The front wheel unit 12 is mounted on a front support member 22 below the front part of the front wheel. The front wheel unit 12 includes a right front wheel unit 12a and a left front wheel unit 12b. The right front wheel unit 12a includes a right front wheel 192, a right gear housing 194, a right motor housing 196, a right pivot pin 198, a right sleeve 200, a right upper arm 202, a right lower arm 204, a right buffer member 206, and a right steering plate 208. The left front wheel unit 12b includes a left front wheel 212, a left gear housing 214, a left motor housing 216, a left pivot pin 218, a left sleeve 220, a left upper arm 222, a left lower arm 224, a left buffer member 226, and a left steering plate 228. In the following description, the right gear housing 194, right pivot pin 198, right sleeve 200, and right steering plate 208 are collectively referred to as the right retaining member 195, and the left gear housing 214, left pivot pin 218, left sleeve 220, and left steering plate 228 are collectively referred to as the left retaining member 215. Furthermore, the right retaining member 195, right upper arm 202, right lower arm 204, right buffer member 206, left retaining member 215, left upper arm 222, left lower arm 224, left buffer member 226, and steering unit 10 are collectively referred to as the suspension mechanism 11.

[0123] like Figure 23 As shown, the right gear housing 194 is positioned to the left of the right front wheel 192. The right motor housing 196 is fixed to the left side of the right gear housing 194. Figure 24 As shown, the right front wheel motor 232 is housed inside the right-side motor housing 196. The right front wheel motor 232 is, for example, an internal rotor type brushless DC motor. The right front wheel motor 232, and the drive control circuit board 46 (see reference) Figure 10 Electrical connection. The right front wheel motor 232 includes: a right front wheel motor shaft 232a extending in the left-right direction, and a Hall sensor 482 (see reference) for detecting the rotation of the right front wheel motor shaft 232a. Figure 32 The right front wheel motor axle 232a is rotatably held in the right motor housing 196 near its left end, and rotatably held in the right gear housing 194 near its right end. The right front wheel 192 includes a right front wheel axle 192a extending to the left. The right front wheel axle 192a is rotatably held in the right gear housing 194 near its left end. A planetary gear mechanism 234 is housed inside the right gear housing 194. The planetary gear mechanism 234 reduces the rotation of the right front wheel motor axle 232a and transmits it to the right front wheel axle 192a. When the right front wheel motor 232 is driven, the rotation of the right front wheel motor axle 232a is transmitted to the right front wheel axle 192a via the planetary gear mechanism 234, thereby causing the right front wheel 192 to rotate.

[0124] The right-side pivot pin 198 is fixed to the upper part of the right-side gear housing 194. The right-side pivot pin 198 extends vertically. The upper part of the right-side pivot pin 198 enters the interior of the right-side sleeve 200. The right-side pivot pin 198 is rotatably held in the right-side sleeve 200 near both the upper and lower ends. Figure 23 As shown, the right end of the upper right arm 202 is connected to the upper part of the right sleeve 200 in a manner that allows it to rotate about a rotation axis in the front-rear direction. The right end of the lower right arm 204 is connected to the lower part of the right sleeve 200 in a manner that allows it to rotate about a rotation axis in the front-rear direction. Figure 18 As shown, the left end of the upper right arm 202 is connected to the upper right connecting portion 22a of the front support member 22 in a manner that allows it to rotate about a rotation axis in the front-rear direction. The left end of the lower right arm 204 is connected to the lower right connecting portion 22b of the front support member 22 in a manner that allows it to rotate about a rotation axis in the front-rear direction. Therefore, the right sleeve 200 is supported on the front support member 22 in a manner that allows it to move within the movable range of the upper right arm 202 and the lower right arm 204.

[0125] The right-side buffer member 206 includes a shock absorber 206a and a coil spring 206b. The upper end of the right-side buffer member 206 is connected to the front surface of the front support member 22 in a manner that allows it to rotate about a rotation axis in the front-rear direction. The lower end of the right-side buffer member 206 is connected to the front surface of the lower right arm 204 in a manner that allows it to rotate about a rotation axis in the front-rear direction. Therefore, when the right front wheel 192 moves vertically relative to the front support member 22, the damping force of the shock absorber 206a and the elastic restoring force of the coil spring 206b can suppress the transmission of impacts or vibrations from the right front wheel 192 to the vehicle base unit 4.

[0126] like Figure 23 As shown, the right steering plate 208 is fixed near the lower end of the right pivot pin 198. The front end of the right connecting rod 172 is connected to the left front end of the right steering plate 208 in a manner that allows it to rotate about two axes orthogonal to the long side of the right connecting rod 172. When viewed from above, the right connecting rod 172 crosses the upper right arm 202 and the lower right arm 204. When the front wheel unit 12 turns to the right (or left), the steering plate 170 (refer to...) Figure 19 The rear end of the right sleeve 200 moves to the right (or left), and thus, when the right pivot pin 198 is viewed from above as the rudder axis, the right steering plate 208, the right pivot pin 198, the right gear housing 194, the right motor housing 196, and the right front wheel 192 rotate clockwise (or counterclockwise) relative to the right sleeve 200.

[0127] like Figure 18 As shown, the left front wheel unit 12b has a configuration that is symmetrical to the right front wheel unit 12a. The following refers to the configuration of the right front wheel unit 12a. Figure 23 , Figure 24 Let's explain the left front wheel unit 12b.

[0128] like Figure 23 As shown, the left gear housing 214 is located on the right side of the left front wheel 212. The left motor housing 216 is fixed to the right side of the left gear housing 214. Figure 24 As shown, the left front wheel motor 242 is housed inside the left motor housing 216. The left front wheel motor 242 is, for example, an internal rotor type brushless DC motor. The left front wheel motor 242 and the drive control circuit board 48 (see reference) Figure 10 Electrical connection. The left front wheel motor 242 includes: a left front wheel motor shaft 242a extending in the left-right direction, and a Hall sensor 484 (see reference) for detecting the rotation of the left front wheel motor shaft 242a. Figure 32 The left front wheel motor axle 242a is rotatably held in the left motor housing 216 near its right end, and rotatably held in the left gear housing 214 near its left end. The left front wheel 212 includes a left axle 212a extending to the right. The left axle 212a is rotatably held in the left gear housing 214 near its right end. A planetary gear mechanism 244 is housed inside the left gear housing 214. The planetary gear mechanism 244 reduces the rotation of the left front wheel motor axle 242a and transmits it to the left axle 212a. When the left front wheel motor 242 is driven, the rotation of the left front wheel motor axle 242a is transmitted to the left axle 212a via the planetary gear mechanism 244, thereby causing the left front wheel 212 to rotate.

[0129] The left pivot pin 218 is fixed to the upper part of the left gear housing 214. The left pivot pin 218 extends vertically. The upper part of the left pivot pin 218 enters the interior of the left sleeve 220. The left pivot pin 218 is rotatably held in the left sleeve 220 near the upper and lower ends. Figure 23 As shown, the left end of the upper left arm 222 is connected to the upper part of the left sleeve 220 in a manner that allows it to rotate about a rotation axis in the front-rear direction. The left end of the lower left arm 224 is connected to the lower part of the left sleeve 220 in a manner that allows it to rotate about a rotation axis in the front-rear direction. Figure 18As shown, the right end of the upper left arm 222 is connected to the upper left connecting portion 22c of the front support member 22 in a manner that allows it to rotate about a rotation axis in the front-rear direction. The right end of the lower left arm 224 is connected to the lower left connecting portion 22d of the front support member 22 in a manner that allows it to rotate about a rotation axis in the front-rear direction. Therefore, the left sleeve 220 is supported on the front support member 22 in a manner that allows it to move within the movable range of the upper left arm 222 and the lower left arm 224.

[0130] The left-side buffer member 226 includes a shock absorber 226a and a coil spring 226b. The upper end of the left-side buffer member 226 is connected to the front surface of the front support member 22 in a manner that allows it to rotate about a rotation axis in the front-rear direction. The lower end of the left-side buffer member 226 is connected to the front surface of the lower left arm 224 in a manner that allows it to rotate about a rotation axis in the front-rear direction. Thus, when the left front wheel 212 moves vertically relative to the front support member 22, the damping force of the shock absorber 226a and the elastic restoring force of the coil spring 226b can suppress the transmission of impacts or vibrations from the left front wheel 212 to the vehicle base unit 4.

[0131] like Figure 23 As shown, the left steering plate 228 is fixed near the lower end of the left pivot pin 218. The front end of the left connecting rod 174 is connected to the right front end of the left steering plate 228 in a manner that allows it to rotate about two axes orthogonal to the long side of the left connecting rod 174. When viewed from above, the left connecting rod 174 crosses the upper left arm 222 and the lower left arm 224. When the front wheel unit 12 turns to the right (or left), the steering plate 170 (refer to...) Figure 19 The rear end of the left pivot pin 218 moves to the right (or left), and thus, when the left sleeve 220 is viewed from above with the axis of the left pivot pin 218 as the steering axis, the left steering plate 228, the left pivot pin 218, the left gear housing 214, the left motor housing 216, and the left front wheel 212 rotate clockwise (or counterclockwise) relative to the left sleeve 220.

[0132] (Rear wheel unit 14)

[0133] like Figure 25 As shown, the rear wheel unit 14 is on the base plate 20 of the vehicle base unit 4 (refer to...). Figure 2The rear wheel unit 14 is mounted on a rear support member 24 below the rear part of the rear wheel. The rear wheel unit 14 includes a right rear wheel unit 14a and a left rear wheel unit 14b. The right rear wheel unit 14a includes a right rear wheel 252, a right gear housing 254, a right motor housing 256, a right brake housing 258, a right clutch lever 260, and a right buffer member 264. The left rear wheel unit 14b includes a left rear wheel 272, a left gear housing 274, a left motor housing 276, a left brake housing 278, a left clutch lever 280, and a left buffer member 284.

[0134] like Figure 26 As shown, the right gear housing 254 is positioned on the left side of the right rear wheel 252, holding the right rear wheel axle (not shown) of the right rear wheel 252 in a rotatable manner. The right gear housing 254 extends forward and upward from the right rear wheel axle. The right motor housing 256 is fixed to the left side of the right gear housing 254 at its upper front. The right brake housing 258 is fixed to the left side of the right motor housing 256. The right rear wheel motor 486 (see reference) is housed inside the right motor housing 256. Figure 30 The right rear wheel motor 486 is, for example, an internal rotor type brushless DC motor. The right rear wheel motor 486 and the drive control circuit board 46 (see reference) Figure 10 Electrical connection. The right rear wheel motor 486 includes: a right rear wheel motor shaft (not shown) extending in the left-right direction, and a Hall sensor 488 (see reference) for detecting the rotation of the right rear wheel motor shaft. Figure 32 The right rear wheel electromagnetic brake 490 is housed in the right brake housing 258 (see reference). Figure 30 The right rear wheel electromagnetic brake 490 is connected to the right rear wheel motor shaft. The right rear wheel electromagnetic brake 490 switches between a state that allows rotation of the right rear wheel motor shaft and a state that prohibits rotation. The right rear wheel electromagnetic brake 490 is connected to the drive control circuit board 46 (see reference). Figure 10 Electrical connection. In parking mode, the right rear wheel electromagnetic brake 490 is maintained in a state that prevents the right rear wheel motor shaft from rotating.

[0135] The right-side gear housing 254 houses a spur gear mechanism (not shown) and a clutch mechanism (not shown). The spur gear mechanism reduces the rotation of the right rear wheel motor shaft and transmits it to the right rear wheel axle. When the right rear wheel motor 486 is driven, the rotation of the right rear wheel motor shaft is transmitted to the right rear wheel axle via the spur gear mechanism, thereby causing the right rear wheel 252 to rotate. The clutch mechanism switches between a state that allows rotation from the right rear wheel motor shaft to the right rear wheel axle and a state that disengages it, depending on the operation of the right-side clutch lever 260. Therefore, when the right rear wheel electromagnetic brake 490 has prohibited the rotation of the right rear wheel motor shaft, the clutch mechanism is switched to a state that disengages rotation from the right rear wheel motor shaft to the right rear wheel axle, thereby preventing the right rear wheel 252 from locking.

[0136] A connecting portion 254a is provided near the upper front end of the right gear housing 254. The connecting portion 254a is connected to the rear support member 24 in a manner that allows it to rotate about a rotation axis in the left-right direction. The right buffer member 264 includes a shock absorber 264a and a coil spring 264b. The upper end of the right buffer member 264 is located above and behind the connecting portion 254a and is connected to the rear support member 24 in a manner that allows it to rotate about a rotation axis in the left-right direction. The lower end of the right buffer member 264 is connected to the upper rear surface of the right gear housing 254 in a manner that allows it to rotate about a rotation axis in the left-right direction. Therefore, when the right rear wheel 252 moves vertically relative to the rear support member 24, the damping force of the shock absorber 264a and the elastic restoring force of the coil spring 264b can suppress the transmission of impacts or vibrations from the right rear wheel 252 to the vehicle base unit 4.

[0137] like Figure 25 As shown, the left rear wheel unit 14b has a configuration that is symmetrical to the right rear wheel unit 14a. The following refers to the configuration of the right rear wheel unit 14a. Figure 26 Let's explain the left rear wheel unit 14b.

[0138] like Figure 26 As shown, the left gear housing 274 is positioned to the right of the left rear wheel 272, holding the left rear wheel axle (not shown) of the left rear wheel 272 in a rotatable manner. The left gear housing 274 extends forward and upward from the left rear wheel axle. The left motor housing 276 is fixed to the right side of the left gear housing 274 at its upper front. The left brake housing 278 is fixed to the right side of the left motor housing 276. The left rear wheel motor 492 (see reference) is housed inside the left motor housing 276. Figure 30 The left rear wheel motor 492 is, for example, an internal rotor type brushless DC motor. The left rear wheel motor 492, and the drive control circuit board 48 (see reference) Figure 10Electrical connection. The left rear wheel motor 492 includes: a left rear wheel motor shaft (not shown) extending in the left-right direction, and a Hall sensor 494 (see reference) for detecting the rotation of the left rear wheel motor shaft. Figure 32 The left rear wheel electromagnetic brake 496 is housed in the left brake housing 278 (see reference). Figure 30 The left rear wheel electromagnetic brake 496 is connected to the left rear wheel motor shaft. The left rear wheel electromagnetic brake 496 switches between a state that allows rotation of the left rear wheel motor shaft and a state that prohibits rotation. The left rear wheel electromagnetic brake 496 and the drive control circuit board 48 (see reference) Figure 10 Electrical connection. The drive control circuit board 48 controls the operation of the left rear wheel electromagnetic brake 496. In parking mode, the left rear wheel electromagnetic brake 496 is maintained in a state that prevents the left rear wheel motor shaft from rotating.

[0139] The left-side gear housing 274 houses a spur gear mechanism (not shown) and a clutch mechanism (not shown). The spur gear mechanism reduces the rotation of the left rear wheel motor shaft and transmits it to the left rear wheel axle. When the left rear wheel motor 492 is driven, the rotation of the left rear wheel motor shaft is transmitted to the left rear wheel axle via the spur gear mechanism, thereby causing the left rear wheel 272 to rotate. The clutch mechanism switches between a state that allows rotation from the left rear wheel motor shaft to the left rear wheel axle and a state that disengages rotation, depending on the operation of the left clutch lever 280. Therefore, when the left rear wheel electromagnetic brake 496 has prohibited the rotation of the left rear wheel motor shaft, the clutch mechanism is switched to a state that disengages rotation from the left rear wheel motor shaft to the left rear wheel axle, thereby preventing the left rear wheel 272 from locking.

[0140] A connecting portion 274a is provided near the upper front end of the left gear housing 274. The connecting portion 274a is connected to the rear support member 24 in a manner that allows it to rotate about a rotation axis in the left-right direction. The left buffer member 284 includes a shock absorber 284a and a coil spring 284b. The upper end of the left buffer member 284 is located above and behind the connecting portion 274a and is connected to the rear support member 24 in a manner that allows it to rotate about a rotation axis in the left-right direction. The lower end of the left buffer member 284 is connected to the upper rear surface of the left gear housing 274 in a manner that allows it to rotate about a rotation axis in the left-right direction. Therefore, when the left rear wheel 272 moves vertically relative to the rear support member 24, the damping force of the shock absorber 284a and the elastic restoring force of the coil spring 284b can suppress the transmission of impacts or vibrations from the left rear wheel 272 to the vehicle base unit 4.

[0141] (Bumper Unit 16)

[0142] like Figure 1As shown, the bumper unit 16 is mounted on the front support member 22, below the front part of the base plate 20 of the vehicle base unit 4. Figure 27 As shown, the bumper unit 16 includes: a base component 500, a housing 502, a right headlight 504, a left headlight 506, a bumper frame 508, bumper support components 510 and 512, a direct-acting tube 514 and 516, a coil spring 518 and 520, and direct-acting bearings 522 and 524 (see reference). Figure 28 ), Abutment plates 526, 528 (refer to) Figure 29 ), and collision monitoring switches 530 and 532 (see reference) Figure 29 ).

[0143] The base component 500 is fixed to the front support component 22 of the vehicle base unit 4 (see reference). Figure 2 ).like Figure 27 As shown, the housing 502 is fixed to the base component 500. The housing 502 includes: a storage portion 502a, which has a generally rectangular box shape with the long side in the left-right direction; a right support portion 502b, which is formed at the right end of the storage portion 502a; and a left support portion 502c, which is formed at the left end of the storage portion 502a. The right headlight 504 is fixed to the right support portion 502b. The left headlight 506 is fixed to the left support portion 502c. The right headlight 504 and the left headlight 506 respectively illuminate the front of the transport vehicle 2. The right headlight 504 and the left headlight 506 are respectively connected to the main control circuit board 44 (see reference). Figure 9 Electrical connection.

[0144] The bumper frame 508 is constructed from a steel tubing. Bumper support components 510 and 512 are respectively positioned behind and fixed to the bumper frame 508. The bumper support component 510 is secured to the bumper frame 508 by means of bolts 534a and 534b and nuts 536a and 536b (see reference). Figure 28 The bumper support component 512 is mounted on the direct drive tube 516 by means of bolts 538a, 538b and nuts 540a, 540b.

[0145] like Figure 28As shown, the direct-acting tube 514 is configured such that its long side is along the longitudinal direction. Near the front end of the direct-acting tube 514, elongated holes 514a and 514b are formed, arranged side-by-side in the longitudinal direction and each having a long side in the longitudinal direction. Bolt 534a passes through elongated hole 514a, and bolt 534b passes through elongated hole 514b. Therefore, the bumper support member 510 is supported on the direct-acting tube 514 in such a way that it can move along the longitudinal direction between the positions where bolts 534a and 534b abut against the front edges of elongated holes 514a and 514b and the positions where bolts 534a and 534b abut against the rear edges of elongated holes 514a and 514b. Similarly, the direct-acting tube 516 is configured such that its long side is along the longitudinal direction. Near the front end of the direct-acting tube 516, elongated holes 516a and 516b are formed, arranged side-by-side in the longitudinal direction and each having a long side in the longitudinal direction. Bolt 538a passes through elongated hole 516a, and bolt 538b passes through elongated hole 516b. Therefore, the bumper support component 512 is supported on the direct-drive tube 516 in such a way that it can move in the front-to-back direction between the positions where bolts 538a and 538b abut against the front edges of elongated holes 516a and 516b and the positions where bolts 538a and 538b abut against the rear edges of elongated holes 516a and 516b.

[0146] The rear ends of the direct-acting tubes 514 and 516 pass through the base component 500 and the front wall of the housing 502, entering the interior of the housing 502. Near their rear ends, the direct-acting tubes 514 and 516 are supported by direct-acting bearings 522 and 524 in a manner movable in the front-rear direction. The direct-acting bearings 522 and 524 are fixed to the front wall of the housing 502. Coil springs 518 and 520 are installed on the direct-acting tubes 514 and 516. The front ends of the coil springs 518 and 520 abut against the rear surfaces of the bumper support components 510 and 512, and the rear ends of the coil springs 518 and 520 abut against the front surface of the base component 500. The coil springs 518 and 520 exert a forward force on the bumper support components 510 and 512 relative to the base component 500.

[0147] like Figure 29As shown, abutment plates 526 and 528 are fixed to the rear ends of the direct-acting tubes 514 and 516. The abutment plates 526 and 528 have abutment portions 526a and 528a extending radially outward. Collision detection switches 530 and 532 are disposed in front of the abutment portions 526a and 528a. When no external force is applied to the bumper frame 508, the direct-acting tubes 514 and 516 move forward relative to the housing 502 due to the force of the coil springs 518 and 520. In this case, the abutment portions 526a and 528a abut against the collision detection switches 530 and 532, and the collision detection switches 530 and 532 are disengaged. When a rearward external force is applied to the bumper frame 508, the direct-acting tubes 514 and 516 overcome the force of the coil springs 518 and 520 and move rearward relative to the housing 502. In this case, the contact portions 526a and 528a disengage from the collision monitoring switches 530 and 532, and the collision monitoring switches 530 and 532 are switched on. The collision monitoring switches 530 and 532 are respectively connected to the main control circuit board 44 (see reference). Figure 9 Electrical connection.

[0148] (Circuit configuration of transport vehicle 2)

[0149] like Figure 30 As shown, the control power supply circuit 432 is electrically connected to the main power switch 96. When the main power switch 96 is turned on, the control power supply circuit 432 allows power from the battery pack 38; when the main power switch 96 is turned off, it prohibits power from the battery pack 38. When the main power of the transport vehicle 2 is off, the control power supply circuit 432 supplies power from the battery pack 38 to the disconnect circuits 438, 440, and 442 without lowering the voltage (Vbat) of the battery pack 38. Conversely, when the main power of the transport vehicle 2 is on, the control power supply circuit 432 lowers the voltage (Vbat) of the battery pack 38 to a specified voltage (Vcc) and supplies it to various electronic components such as the main MCU 434, switching circuit 436, automatic operation MCU 430, and motor MCUs 444, 446, 448, 450, and 452. Hereinafter, the voltage (Vbat) of the battery pack 38 will be referred to as the battery potential, and the voltage (Vcc) that is reduced by the control power circuit 432 will be referred to as the power supply potential.

[0150] The main MCU 434 controls the overall movement of the transport vehicle 2. The main power switch 96, speed switch 104, horn switch 106, LED 476, buzzer 478, steering angle sensor 166, overload monitoring sensors 320a, 320b, 320c, 320d, right headlight 504, and left headlight 506 are all electrically connected to the main MCU 434. Additionally, the mode switch 98, trigger switch 100, travel direction switch 102, emergency stop switch 308, collision monitoring switches 530, 532, and rotation angle sensor 88 are electrically connected to the main MCU 434 via switching circuit 436. Furthermore, the wireless I / F 428 is electrically connected to the main MCU 434 via automatic operation MCU 430. The automatic operation MCU430 generates, based on the signal from the wireless I / F428, the travel path that the transport vehicle 2 should achieve when it is in automatic or remote control operation, and outputs it as a command value to the main MCU434.

[0151] Motor MCUs 444, 446, 448, 450, and 452 are electrically connected to the main MCU 434. Motor MCU 444 controls the operation of the right front wheel motor 232 via motor driver 454, and also controls the operation of the brake circuit 468 and cooling fan 50d. Motor MCU 446 controls the operation of the left front wheel motor 242 via motor driver 456, and also controls the operation of the brake circuit 470 and cooling fan 52d. Motor MCU 448 controls the operation of the right rear wheel motor 486 via motor driver 458, and also controls the operation of the brake circuit 472 and cooling fan 54d. Additionally, motor MCU 448 controls the operation of the right rear wheel electromagnetic brake 490 via electromagnetic brake driver 464. Motor MCU 450 controls the operation of the left rear wheel motor 492 via motor driver 460, and also controls the operation of the brake circuit 474 and cooling fan 56d. Additionally, the motor MCU 450 controls the operation of the left rear wheel electromagnetic brake 496 via the electromagnetic brake driver 466. The motor MCU 452 controls the operation of the steering motor 176 via the motor driver 462.

[0152] Disconnection circuit 438 is configured on the power supply path from control power circuit 432 to motor drivers 454, 456, 458, and 460. Disconnection circuit 438 switches between a state where power supply from control power circuit 432 to motor drivers 454, 456, 458, and 460 is permitted and a state where power supply is prohibited. Disconnection circuit 440 is configured on the power supply path from control power circuit 432 to electromagnetic brake drivers 464 and 466. Disconnection circuit 440 switches between a state where power supply from control power circuit 432 to electromagnetic brake drivers 464 and 466 is permitted and a state where power supply is prohibited. Disconnection circuit 442 is configured on the power supply path from control power circuit 432 to motor driver 462. Disconnection circuit 442 switches between a state where power supply from control power circuit 432 to motor driver 462 is permitted and a state where power supply is prohibited. Disconnection circuits 438, 440, and 442 are all electrically connected to the main MCU 434 and the switching circuit 436.

[0153] (The configuration of switching circuit 436)

[0154] like Figure 31 As shown, the switching circuit 436 includes: elimination circuits 542, 544, 546, delay circuit 548, AND gates 550, 552, OR gates 554, 556, NOT gates 558, 560, 562, 564, 566, and resistors 568, 570, 572, 574, 576, 578.

[0155] The mode switch 98 includes: a ground terminal 98a, a manual mode terminal 98b, and an automatic mode terminal 98c. The ground terminal 98a is connected to the ground potential. The manual mode terminal 98b is connected to the power supply potential via resistor 568, and is also connected to the main MCU 434. The automatic mode terminal 98c is connected to the power supply potential via resistor 570, and is also connected to the main MCU 434.

[0156] When the user selects manual mode at mode switch 98, ground terminal 98a and manual mode terminal 98b are connected, while ground terminal 98a and automatic mode terminal 98c are not connected. In this case, manual mode terminal 98b is at low potential (L), and automatic mode terminal 98c is at high potential (H). When the input from manual mode terminal 98b is low potential, the main MCU 434 will recognize that the user has selected manual mode. When the user selects automatic mode at mode switch 98, ground terminal 98a and manual mode terminal 98b are not connected, while ground terminal 98a and automatic mode terminal 98c are connected. In this case, manual mode terminal 98b is at high potential (H), and automatic mode terminal 98c is at low potential (L). When the input from automatic mode terminal 98c is low potential (L), the main MCU 434 will recognize that the user has selected automatic mode. When the user selects parking mode at mode switch 98, ground terminal 98a and manual mode terminal 98b are not connected, and ground terminal 98a and automatic mode terminal 98c are also not connected. In this case, both the manual mode terminal 98b and the automatic mode terminal 98c are at a high potential (H). When both the input from the manual mode terminal 98b and the input from the automatic mode terminal 98c are at a high potential (H), the main MCU434 will recognize that the user has selected the parking mode.

[0157] The elimination circuit 542 includes a transistor 542a and resistors 542b, 542c, and 542d. Transistor 542a is a PNP transistor. One end of resistor 542b is connected to the emitter of transistor 542a, and the other end is connected to the base of transistor 542a. One end of resistor 542c is connected to the base of transistor 542a, and the other end is connected to the automatic mode terminal 98c of the mode switch 98. One end of resistor 542d is connected to the rotation angle sensor 88, and the other end is connected to the collector of transistor 542a. Furthermore, the emitter of transistor 542a is connected to the power supply potential, and the collector of transistor 542a is connected to the main MCU 434.

[0158] The rotation angle sensor 88 outputs a potential corresponding to the rotation angle to the cancellation circuit 542. When the automatic mode terminal 98c is at a high potential (H), transistor 542a is turned off, and the potential output from the rotation angle sensor 88 is input to the main MCU 434. When the automatic mode terminal 98c is at a low potential (L), transistor 542a is turned on, and the high potential (H) is input to the main MCU 434, regardless of the potential output from the rotation angle sensor 88. That is, when the automatic mode is selected by the mode switch 98, the cancellation circuit 542 cancels the input signal from the rotation angle sensor 88.

[0159] The trigger switch 100 includes a ground terminal 100a, a trigger terminal 100b, and a variable resistor 100c. The ground terminal 100a is connected to a ground potential. The trigger terminal 100b is connected to a power supply potential via a resistor 572. When the user does not activate the trigger switch 100, the ground terminal 100a and trigger terminal 100b are not conductive, and trigger terminal 100b is at potential H. When the user activates the trigger switch 100, the ground terminal 100a and trigger terminal 100b are conductive, and trigger terminal 100b is at potential L. One end of the variable resistor 100c of the trigger switch 100 is connected to the ground potential, and the other end is connected to the power supply potential. The potential corresponding to the amount pressed when the user activates the trigger switch 100 is output to the cancellation circuit 544.

[0160] The elimination circuit 544 includes a transistor 544a and resistors 544b, 544c, and 544d. Transistor 544a is a PNP transistor. One end of resistor 544b is connected to the emitter of transistor 544a, and the other end is connected to the base of transistor 544a. One end of resistor 544c is connected to the base of transistor 544a, and the other end is connected to the automatic mode terminal 98c of the mode switch 98. One end of resistor 544d is connected to the variable resistor 100c of the trigger switch 100, and the other end is connected to the collector of transistor 544a. Furthermore, the emitter of transistor 544a is connected to the power supply potential, and the collector of transistor 544a is connected to the main MCU 434.

[0161] When the automatic mode terminal 98c is at a potential of H, transistor 544a is turned off, and the potential output from variable resistor 100c is input to the main MCU 434. In this case, the main MCU 434 identifies the user's operation on trigger switch 100 based on the potential output from variable resistor 100c. When the automatic mode terminal 98c is at a potential of L, transistor 544a is turned on, and a potential of H is input to the main MCU 434, regardless of the potential output from variable resistor 100c. That is, when automatic mode is selected at mode switch 98, the cancellation circuit 544 cancels the input signal from variable resistor 100c from trigger switch 100.

[0162] The trigger terminal 100b of trigger switch 100 is connected to the first input terminal of OR gate 554 via NOT gate 558. The automatic mode terminal 98c of mode switch 98 is connected to the second input terminal of OR gate 554 via NOT gate 560. The output terminal of OR gate 554 is connected to the first input terminal of AND gate 550. The output terminal of AND gate 550 is connected to cut-off circuit 438. As described later, when the output terminal of AND gate 550 is at potential H, cut-off circuit 438 allows power to be supplied to motor drivers 454, 456, 458, and 460, and when the output terminal of AND gate 550 is at potential L, it cuts off the power supply to motor drivers 454, 456, 458, and 460.

[0163] As described later, the second input terminal of the AND gate 550 is typically input to a potential of H. In this case, if the automatic mode terminal 98c is at a potential of H, then when the trigger terminal 100b is at a potential of H, the output terminals of the OR gate 554 and the AND gate 550 are at potentials of L; and when the trigger terminal 100b is at a potential of L, the output terminals of the OR gate 554 and the AND gate 550 are at potentials of H. Therefore, when automatic mode is not selected at the mode switch 98, when the trigger switch 100 is turned on, the cut-off circuit 438 is input to a potential of H; when the trigger switch 100 is not turned on, the cut-off circuit 438 is input to a potential of L. Conversely, if the automatic mode terminal 98c is at a potential of L, then the output terminals of the OR gate 554 and the AND gate 550 are at potentials of H, regardless of the potential of the trigger terminal 100b. Therefore, when the automatic mode is selected at the mode switching switch 98, the switching circuit 436 inputs a potential H to the cut-off circuit 438, regardless of whether the trigger switch 100 has been turned on.

[0164] The output terminal of AND gate 550 is also connected to the input terminal of delay circuit 548. The output terminal of delay circuit 548 is connected to cut-off circuit 440. As described later, when the output terminal of delay circuit 548 is at potential H, cut-off circuit 440 allows power to be supplied to electromagnetic brake actuators 464 and 466; when the output terminal of delay circuit 548 is at potential L, cut-off circuit 440 cuts off power supply to electromagnetic brake actuators 464 and 466. Delay circuit 548 includes: diode 548a, resistor 548b, capacitor 548c, and buffer gate 548d. The anode of diode 548a is connected to the input terminal of delay circuit 548. The cathode of diode 548a is connected to the input terminal of buffer gate 548d. One end of resistor 548b is connected to the cathode of diode 548a, and the other end is connected to ground potential. One end of capacitor 548c is connected to the cathode of diode 548a, and the other end is connected to ground potential. The output terminal of buffer gate 548d is connected to the output terminal of delay circuit 548. When the output terminal of AND gate 550 switches from potential L to potential H, after a predetermined delay time determined by the time constant of resistor 548b and capacitor 548c, the output terminal of delay circuit 548 also switches from potential L to potential H. Similarly, when the output terminal of AND gate 550 switches from potential H to potential L, after a predetermined delay time determined by the time constant of resistor 548b and capacitor 548c, the output terminal of delay circuit 548 also switches from potential H to potential L.

[0165] Emergency stop switch 308 includes a ground terminal 308a and an emergency stop terminal 308b. Ground terminal 308a is connected to ground potential. Emergency stop terminal 308b is connected to power supply potential via resistor 574 and is also connected to the main MCU 434. When emergency stop switch 308 is open, ground terminal 308a and emergency stop terminal 308b are connected, and emergency stop terminal 308b is at potential L. When emergency stop switch 308 is closed, ground terminal 308a and emergency stop terminal 308b are not connected, and emergency stop terminal 308b is at potential H. When the input from emergency stop terminal 308b is potential H, the main MCU 434 recognizes that the user has closed emergency stop switch 308.

[0166] Collision detection switch 530 includes a ground terminal 530a and a collision detection terminal 530b. Collision detection switch 532 includes a ground terminal 532a and a collision detection terminal 532b. Ground terminal 530a is connected to a ground potential. Collision detection terminal 530b is connected to ground terminal 532a. Collision detection terminal 532b is connected to a power supply potential via resistor 576 and is also connected to the main MCU 434. When collision detection switch 530 is open, ground terminal 530a and collision detection terminal 530b are connected; when collision detection switch 530 is closed, ground terminal 530a and collision detection terminal 530b are not connected. When collision detection switch 532 is open, ground terminal 532a and collision detection terminal 532b are connected; when collision detection switch 532 is closed, ground terminal 532a and collision detection terminal 532b are not connected. Therefore, when both collision detection switches 530 and 532 are open, the collision detection terminal 532b is at potential L; when one or both of the collision detection switches 530 and 532 are closed, the collision detection terminal 532b is at potential H. When the input from the collision detection terminal 532b is at potential H, the main MCU 434 recognizes that a collision has been detected through the collision detection switches 530 and 532.

[0167] The travel direction switching switch 102 includes a ground terminal 102a and a travel direction terminal 102b. The ground terminal 102a is connected to a ground potential. The travel direction terminal 102b is connected to an elimination circuit 546. With the travel direction switching switch 102, when the user selects forward, the ground terminal 102a and the travel direction terminal 102b are not connected; when the user selects backward, the ground terminal 102a and the travel direction terminal 102b are connected.

[0168] The elimination circuit 546 includes a transistor 546a and resistors 546b, 546c, and 546d. Transistor 546a is a PNP transistor. One end of resistor 546b is connected to the emitter of transistor 546a, and the other end is connected to the base of transistor 546a. One end of resistor 546c is connected to the base of transistor 546a, and the other end is connected to the automatic mode terminal 98c of the mode switch 98. One end of resistor 546d is connected to the travel direction terminal 102b of the travel direction switch 102, and the other end is connected to the collector of transistor 546a. Furthermore, the emitter of transistor 546a is connected to the power supply potential, and the collector of transistor 546a is connected to the power supply potential via resistor 578 and is also connected to the main MCU 434.

[0169] When the automatic mode terminal 98c is at potential H, transistor 546a is off. The collector of transistor 546a is at potential H if forward is selected at the travel direction switch 102, and at potential L if backward is selected at the travel direction switch 102. In this case, the main MCU 434 identifies whether forward or backward is selected based on the input potential. When the automatic mode terminal 98c is at potential L, transistor 546a is on, and its collector is at potential H, regardless of whether forward or backward is selected at the travel direction switch 102. That is, when automatic mode is selected at mode switch 98, the cancellation circuit 546 cancels the input signal from the travel direction switch 102.

[0170] The emergency stop terminal 308b of the emergency stop switch 308 is connected to the first input terminal of the AND gate 552 via the NOT gate 562. The collision detection terminal 532b of the collision detection switch 532 is connected to the first input terminal of the OR gate 556 via the NOT gate 562. The collector of the transistor 546a of the elimination circuit 546 is connected to the second input terminal of the OR gate 556 via the NOT gate 564. The output terminal of the OR gate 556 is connected to the second input terminal of the AND gate 552. The output terminal of the AND gate 552 is connected to the second input terminal of the AND gate 550, and also to the cutoff circuit 442. As described later, when the output terminal of the AND gate 552 is at a potential of H, the cutoff circuit 442 allows power to be supplied to the motor driver 462, and when the output terminal of the AND gate 552 is at a potential of L, it cuts off the power supply to the motor driver 462.

[0171] When the emergency stop terminal 308b is at potential H, the output terminal of the AND gate 552 is at potential L, regardless of the potential of the output terminal of the OR gate 556. Therefore, when the emergency stop switch 308 is turned on, potential L is input to the second input terminal of the AND gate 550, and potential L is input from the switching circuit 436 to the cut-off circuit 442, regardless of the state of the mode switching switch 98, the collision monitoring switches 530, 532, or the direction of travel switching switch 102.

[0172] When the emergency stop terminal 308b is at a low potential (L), and this low potential is input to the second input terminal of the OR gate 556, if the collision detection terminal 532b is at a low potential, then the output terminals of the OR gate 556 and the AND gate 552 are at high potentials (H). Conversely, if the collision detection terminal 532b is at a high potential, then the output terminals of the OR gate 556 and the AND gate 552 are at low potentials (L). Therefore, when the collision detection switches 530 and 532 do not detect a collision, the second input terminal of the AND gate 550 is at a high potential (H), and this high potential is input from the switching circuit 436 to the cutoff circuit 442. When the collision detection switches 530 and 532 detect a collision, the low potential is input to the second input terminal of the AND gate 550, and this low potential is input from the switching circuit 436 to the cutoff circuit 442. In other words, the collision detection implemented by the collision detection switches 530 and 532 is activated.

[0173] When the emergency stop terminal 308b is at potential L and potential H is input to the second input terminal of OR gate 556, the output terminals of OR gate 556 and AND gate 552 are at potential H, independent of the potential of collision monitoring terminal 532b. Therefore, potential H is input to the second input terminal of AND gate 550, and potential H is input from switching circuit 436 to cut-off circuit 442, independent of the states of collision monitoring switches 530 and 532. That is, collision monitoring implemented by collision monitoring switches 530 and 532 is disabled.

[0174] When the automatic mode terminal 98c is at potential H, since transistor 546a of the cancellation circuit 546 is off, if the travel direction terminal 102b is at potential H, potential L is input to the second input terminal of OR gate 556; if the travel direction terminal 102b is at potential L, potential H is input to the second input terminal of OR gate 556. That is, when automatic mode is not selected at mode switch 98, when forward is selected at travel direction switch 102, collision monitoring implemented by collision monitoring switches 530 and 532 is enabled; when reverse is selected at travel direction switch 102, collision monitoring implemented by collision monitoring switches 530 and 532 is disabled.

[0175] When the automatic mode terminal 98c is at the L potential, since the transistor 546a of the cancellation circuit 546 is turned on, the L potential is input to the second input terminal of the OR gate 556, regardless of the potential of the travel direction terminal 102b. That is, when the automatic mode is selected at the mode switch 98, the collision detection implemented by the collision detection switches 530 and 532 is activated, regardless of the state of the travel direction switch 102.

[0176] (Construction of the cut-off circuit 438)

[0177] like Figure 32 As shown, the cutoff circuit 438 includes a switching element 438a, a driver IC 438b, and an AND gate 438c. The switching element 438a is, for example, a field-effect transistor, specifically an n-channel MOSFET with an insulated gate. The drain of the switching element 438a is connected to the battery potential (Vbat) output of the control power supply circuit 432, the source of the switching element 438a is connected to motor drivers 454, 456, 458, and 460, and the gate of the switching element 438a is connected to the driver IC 438b. The first input terminal of the AND gate 438c is connected to the switching circuit 436, the second input terminal of the AND gate 438c is connected to the main MCU 434, and the output terminal of the AND gate 438c is connected to the driver IC 438b. When the output terminal of the AND gate 438c is at a potential of H, that is, when both the first and second input terminals of the AND gate 438c are at a potential of H, the driver IC 438b turns on the switching element 438a. When the output terminal of AND gate 438c is at a low potential, that is, when one or both of the first and second input terminals of AND gate 438c are at a low potential, driver IC 438b prevents switching element 438a from conducting.

[0178] (Composition of motor drivers 454, 456, 458, and 460)

[0179] Motor drivers 454, 456, 458, and 460 are connected to the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, and left rear wheel motor 492 via the U-phase output terminal, V-phase output terminal, and W-phase output terminal, respectively. Additionally, motor drivers 454, 456, 458, and 460 are connected to brake circuits 468, 470, 472, and 474 via brake circuit output terminals.

[0180] Motor drivers 454, 456, 458, and 460 include: first switching elements 454a, 456a, 458a, and 460a; second switching elements 454b, 456b, 458b, and 460b; third switching elements 454c, 456c, 458c, and 460c; fourth switching elements 454d, 456d, 458d, and 460d; fifth switching elements 454e, 456e, 458e, and 460e; sixth switching elements 454f, 456f, 458f, and 460f; first diodes 454g, 456g, 458g, and 460g; second diodes 454h, 456h, 458h, and 460h; and third diodes 454i, 456i, 458i, and 460i. The first switching element 454a, 456a, 458a, 460a, the second switching element 454b, 456b, 458b, 460b, the third switching element 454c, 456c, 458c, 460c, the fourth switching element 454d, 456d, 458d, 460d, the fifth switching element 454e, 456e, 458e, 460e, and the sixth switching element 454f, 456f, 458f, 460f are, for example, field-effect transistors, specifically, n-channel MOSFETs with insulated gates.

[0181] The drains of the first switching elements 454a, 456a, 458a, and 460a are connected to the source of the switching element 438a in the cutoff circuit 438. The sources of the first switching elements 454a, 456a, 458a, and 460a are connected to the U-phase output terminal. The gates of the first switching elements 454a, 456a, 458a, and 460a are connected to the motor MCUs 444, 446, 448, and 450. The drains of the second switching elements 454b, 456b, 458b, and 460b are connected to the U-phase output terminal. The sources of the second switching elements 454b, 456b, 458b, and 460b are connected to the ground potential. The gates of the second switching elements 454b, 456b, 458b, and 460b are connected to the motor MCUs 444, 446, 448, and 450.

[0182] The drains of the third switching elements 454c, 456c, 458c, and 460c are connected to the source of the switching element 438a in the cutoff circuit 438. The sources of the third switching elements 454c, 456c, 458c, and 460c are connected to the V-phase output terminal. The gates of the third switching elements 454c, 456c, 458c, and 460c are connected to the motor MCUs 444, 446, 448, and 450. The drains of the fourth switching elements 454d, 456d, 458d, and 460d are connected to the V-phase output terminal. The sources of the fourth switching elements 454d, 456d, 458d, and 460d are connected to ground potential. The gates of the fourth switching elements 454d, 456d, 458d, and 460d are connected to the motor MCUs 444, 446, 448, and 450.

[0183] The drains of the fifth switching elements 454e, 456e, 458e, and 460e are connected to the source of the switching element 438a in the cutoff circuit 438. The sources of the fifth switching elements 454e, 456e, 458e, and 460e are connected to the W-phase output terminal. The gates of the fifth switching elements 454e, 456e, 458e, and 460e are connected to the motor MCUs 444, 446, 448, and 450. The drains of the sixth switching elements 454f, 456f, 458f, and 460f are connected to the W-phase output terminal. The sources of the sixth switching elements 454f, 456f, 458f, and 460f are connected to the ground potential. The gates of the sixth switching elements 454f, 456f, 458f, and 460f are connected to the motor MCUs 444, 446, 448, and 450.

[0184] The detection signals from Hall sensors 482, 484, 488, and 494 of the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, and left rear wheel motor 492 are input to the motor MCUs 444, 446, 448, and 450. Motor MCUs 444, 446, 448, and 450 switch the first switching elements 454a, 456a, 458a, and 460a, the second switching elements 454b, 456b, 458b, and 460b, the third switching elements 454c, 456c, 458c, and 460c, the fourth switching elements 454d, 456d, 458d, and 460d, the fifth switching elements 454e, 456e, 458e, and 460e, and the sixth switching elements 454f, 456f, 458f, and 460f to the on / off state based on detection signals from Hall sensors 482, 484, 488, and 494. This allows the right front wheel motor 232, the left front wheel motor 242, the right rear wheel motor 486, and the left rear wheel motor 492 to operate at the desired rotational speed. In addition, motor MCUs 444, 446, 448, and 450 can brake the rotation of the right front wheel motor 232, the left front wheel motor 242, the right rear wheel motor 486, and the left rear wheel motor 492 by switching the second switching elements 454b, 456b, 458b, and 460b, the fourth switching elements 454d, 456d, 458d, and 460d, and the sixth switching elements 454f, 456f, 458f, and 460f to the on state using so-called short-circuit braking.

[0185] The anodes of diodes 454g, 456g, 458g, and 460g are connected to the U-phase output terminal, and the cathodes of diodes 454g, 456g, 458g, and 460g are connected to the brake circuit output terminal. The anodes of diodes 454h, 456h, 458h, and 460h are connected to the V-phase output terminal, and the cathodes of diodes 454h, 456h, 458h, and 460h are connected to the brake circuit output terminal. The anodes of diodes 454i, 456i, 458i, and 460i are connected to the W-phase output terminal, and the cathodes of diodes 454i, 456i, 458i, and 460i are connected to the brake circuit output terminal.

[0186] (The configuration of braking circuits 468, 470, 472, and 474)

[0187] The braking circuits 468, 470, 472, and 474 include: switching elements 468a, 470a, 472a, and 474a; resistors 468b, 470b, 472b, and 474b; amplifiers 468c, 470c, 472c, and 474c; operational amplifiers 468d, 470d, 472d, and 474d; and thermistors 468e, 470e, 472e, and 474e.

[0188] Switching elements 468a, 470a, 472a, and 474a are, for example, field-effect transistors, specifically n-channel MOSFETs with insulated gates. The drains of switching elements 468a, 470a, 472a, and 474a are connected to the braking circuit output terminals of motor drivers 454, 456, 458, and 460. The sources of switching elements 468a, 470a, 472a, and 474a are connected to ground potential via resistors 468b, 470b, 472b, and 474b. The gates of switching elements 468a, 470a, 472a, and 474a are connected to the output terminals of operational amplifiers 468d, 470d, 472d, and 474d. Switching elements 468a, 470a, 472a, and 474a can operate in linear mode and switching mode depending on the gate voltage. The linear mode is characterized by a roughly linear change in drain current when the gate voltage changes, while the switching mode is characterized by a relatively stable drain current even when the gate voltage changes.

[0189] Amplifiers 468c, 470c, 472c, and 474c detect the voltage between one end of resistors 468b, 470b, 472b, and 474b, amplify the detected voltage, and output it to the inverting input terminals of operational amplifiers 468d, 470d, 472d, and 474d. The non-inverting input terminals of operational amplifiers 468d, 470d, 472d, and 474d are connected to motor MCUs 444, 446, 448, and 450. Operational amplifiers 468d, 470d, 472d, and 474d apply the voltage corresponding to the difference between the current command value input to the non-inverting input terminal of motor MCUs 444, 446, 448, and 450 and the current detection value input to the inverting input terminal of amplifiers 468c, 470c, 472c, and 474c to the gates of switching elements 468a, 470a, 472a, and 474a. Accordingly, switching elements 468a, 470a, 472a, and 474a operate in linear mode, controlling the operation of switching elements 468a, 470a, 472a, and 472a by the current corresponding to the current command value from motor MCUs 444, 446, 448, and 450 flowing through resistors 468b, 470b, 472b, and 474b. That is, braking circuits 468, 470, 472, and 474 can be used as linear regulators.

[0190] When the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, and left rear wheel motor 492 rotate, a large current flowing from the motor drivers 454, 456, 458, and 460 to the braking circuits 468, 470, 472, and 474 will exert a strong braking force on these motors. Therefore, during the rotation of these motors, the motor MCUs 444, 446, 448, and 450 can exert a significant braking force on them through the braking circuits 468, 470, 472, and 474.

[0191] When braking force is applied to the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, and left rear wheel motor 492 via braking circuits 468, 470, 472, and 474, a large current flows through the switching elements 468a, 470a, 472a, and 472a and the resistors 468b, 470b, 472b, and 474b. Therefore, the temperature of braking circuits 468, 470, 472, and 474 rises due to heat generation. Consequently, when the motor MCUs 444, 446, 448, and 450 activate braking circuits 468, 470, 472, and 474, they drive cooling fans 50d, 52d, 54d, and 56d to cool the braking circuits 468, 470, 472, and 474. Additionally, thermistors 468e, 470e, 472e, and 474e are connected to the motor MCUs 444, 446, 448, and 450. Thermistors 468e, 470e, 472e, and 474e detect the temperature of the braking circuits 468, 470, 472, and 474, and output the results to the motor MCUs 444, 446, 448, and 450.

[0192] Alternatively, the braking circuits 468, 470, 472, and 474 can be configured as follows: a group of multiple (e.g., six) switching elements 468a, 470a, 472a, and 474a; resistors 468b, 470b, 472b, and 474b; amplifiers 468c, 470c, 472c, and 474c; operational amplifiers 468d, 470d, 472d, and 474d; and thermistors 468e, 470e, 472e, and 474e are prepared and connected in parallel. With this configuration, a larger current can flow from the motor drivers 454, 456, 458, and 460 to the braking circuits 468, 470, 472, and 474, thereby enabling a greater braking force to be applied to the right front wheel motor 232, the left front wheel motor 242, the right rear wheel motor 486, and the left rear wheel motor 492.

[0193] (Construction of the cut-off circuit 440)

[0194] like Figure 33 As shown, the cutoff circuit 440 includes a switching element 440a, a driver IC 440b, and an AND gate 440c. The switching element 440a is, for example, a field-effect transistor, specifically an n-channel MOSFET with an insulated gate. The drain of the switching element 440a is connected to the battery potential (Vbat) output of the control power supply circuit 432, the source of the switching element 440a is connected to the electromagnetic brake drivers 464 and 466, and the gate of the switching element 440a is connected to the driver IC 440b. The first input terminal of the AND gate 440c is connected to the switching circuit 436, the second input terminal of the AND gate 440c is connected to the main MCU 434, and the output terminal of the AND gate 440c is connected to the driver IC 440b. When the output terminal of the AND gate 440c is at potential H, that is, when both the first and second input terminals of the AND gate 440c are at potential H, the driver IC 440b turns on the switching element 440a. When the output terminal of AND gate 440c is at a low potential, that is, when one or both of the first and second input terminals of AND gate 440c are at a low potential, driver IC 440b prevents switching element 440a from conducting.

[0195] (Composition of electromagnetic brake actuators 464 and 466)

[0196] Electromagnetic brake actuators 464 and 466 are connected to the right rear wheel electromagnetic brake 490 and the left rear wheel electromagnetic brake 496 via positive and negative output terminals, respectively. Electromagnetic brake actuators 464 and 466 include switching elements 464a and 466a, and diodes 464b and 466b.

[0197] Switching elements 464a and 466a are, for example, field-effect transistors, specifically, n-channel MOSFETs with insulated gates. The drains of switching elements 464a and 466a are connected to the negative output terminal, and the sources are connected to ground. The gates of switching elements 464a and 466a are connected to the motor MCUs 448 and 450. The anodes of diodes 464b and 466b are connected to the negative output terminal, and the cathodes are connected to the positive output terminal.

[0198] When no external voltage is applied between the positive and negative output terminals of the right rear wheel electromagnetic brake 490 and the left rear wheel electromagnetic brake 496, braking force is applied to the right rear wheel motor 486 and the left rear wheel motor 492. When an external voltage is applied between the positive and negative output terminals, the braking force on the right rear wheel motor 486 and the left rear wheel motor 492 is released. When the switching element 440a of the cutoff circuit 440 is turned on, the motor MCUs 448 and 450 turn on the switching elements 464a and 466a of the electromagnetic brake drivers 464 and 466, respectively. The battery voltage (Vbat) is then applied between the positive and negative output terminals, thereby releasing the braking force of the right rear wheel electromagnetic brake 490 and the left rear wheel electromagnetic brake 496. Additionally, diodes 464b and 466b absorb reverse surges from the right rear wheel electromagnetic brake 490 and the left rear wheel electromagnetic brake 496.

[0199] (Construction of the cut-off circuit 442)

[0200] like Figure 34 As shown, the cutoff circuit 442 includes a switching element 442a, a driver IC 442b, and an AND gate 442c. The switching element 442a is, for example, a field-effect transistor, specifically an n-channel MOSFET with an insulated gate. The drain of the switching element 442a is connected to the battery potential (Vbat) output of the control power supply circuit 432, the source of the switching element 442a is connected to the motor driver 462, and the gate of the switching element 442a is connected to the driver IC 442b. The first input terminal of the AND gate 442c is connected to the switching circuit 436, the second input terminal of the AND gate 442c is connected to the main MCU 434, and the output terminal of the AND gate 442c is connected to the driver IC 442b. When the output terminal of the AND gate 442c is at potential H, that is, when both the first and second input terminals of the AND gate 442c are at potential H, the driver IC 442b turns on the switching element 442a. When the output terminal of AND gate 442c is at a low potential, that is, when one or both of the first and second input terminals of AND gate 442c are at a low potential, driver IC 442b prevents switching element 442a from conducting.

[0201] (Composition of motor driver 462)

[0202] The motor driver 462 is connected to the steering motor 176 via the U-phase output terminal, the V-phase output terminal, and the W-phase output terminal. The motor driver 462 includes a first switching element 462a, a second switching element 462b, a third switching element 462c, a fourth switching element 462d, a fifth switching element 462e, and a sixth switching element 462f. The first switching element 462a, the second switching element 462b, the third switching element 462c, the fourth switching element 462d, the fifth switching element 462e, and the sixth switching element 462f are, for example, field-effect transistors, specifically, n-channel MOSFETs with insulated gates.

[0203] The drain of the first switching element 462a is connected to the source of the switching element 442a in the cutoff circuit 442. The source of the first switching element 462a is connected to the U-phase output terminal. The gate of the first switching element 462a is connected to the motor MCU 452. The drain of the second switching element 462b is connected to the U-phase output terminal. The source of the second switching element 462b is connected to ground potential. The gate of the second switching element 462b is connected to the motor MCU 452.

[0204] The drain of the third switching element 462c is connected to the source of the switching element 442a in the cutoff circuit 442. The source of the third switching element 462c is connected to the V-phase output terminal. The gate of the third switching element 462c is connected to the motor MCU 452. The drain of the fourth switching element 462d is connected to the V-phase output terminal. The source of the fourth switching element 462d is connected to ground potential. The gate of the fourth switching element 462d is connected to the motor MCU 452.

[0205] The drain of the fifth switching element 462e is connected to the source of the switching element 442a in the cutoff circuit 442. The source of the fifth switching element 462e is connected to the W-phase output terminal. The gate of the fifth switching element 462e is connected to the motor MCU 452. The drain of the sixth switching element 462f is connected to the W-phase output terminal. The source of the sixth switching element 462f is connected to ground potential. The gate of the sixth switching element 462f is connected to the motor MCU 452.

[0206] The detection signal from the Hall sensor 480 of the steering motor 176 is input to the motor MCU 452. Based on the detection signal from the Hall sensor 480, the motor MCU 452 switches the first switching element 462a, the second switching element 462b, the third switching element 462c, the fourth switching element 462d, the fifth switching element 462e, and the sixth switching element 462f on / off, thereby enabling the steering motor 176 to operate at the desired rotational speed. Furthermore, by switching the second switching element 462b, the fourth switching element 462d, and the sixth switching element 462f on, the motor MCU 452 can brake the rotation of the steering motor 176 using a so-called short-circuit braking mechanism.

[0207] (Processing performed by the main MCU434)

[0208] When the main power supply of the transport vehicle 2 is turned on, the main MCU434 executes... Figure 35 - Figure 37 The processing shown.

[0209] like Figure 35 As shown, in S2, the main MCU434 sets the temperature protection flag to 0.

[0210] In S4, the main MCU 434 determines whether to use any one of the overload monitoring sensors 320a, 320b, 320c, or 320d to monitor the overload. If overload monitoring is performed (YES), the process proceeds to S6. In S6, the main MCU 434 sets the overload monitoring flag to 1. If overload monitoring is not performed in S4 (NO), the process proceeds to S8. In S8, the main MCU 434 sets the overload monitoring flag to 0. After S6 or S8, the process proceeds to S10.

[0211] In S10, the main MCU 434 determines whether to use either collision detection switch 530 or 532 to monitor for collisions. If collision monitoring is performed (YES), the process proceeds to S12. In S12, the main MCU 434 sets the collision detection flag to 1. If collision monitoring is not performed in S10 (NO), the process proceeds to S14. In S14, the main MCU 434 sets the collision detection flag to 0. After S12 or S14, the process proceeds to S16.

[0212] In S16, the main MCU 434 determines whether the braking circuit temperature T detected by thermistors 468e, 470e, 472e, and 474e exceeds the temperature protection threshold T1. If the braking circuit temperature T exceeds the temperature protection threshold T1 (in the case of YES), the process proceeds to S18. In S18, the main MCU 434 sets the temperature protection flag to 1. After S18, the process proceeds to S20. If the braking circuit temperature T in S16 does not exceed the temperature protection threshold T1 (in the case of NO), the process proceeds to S20.

[0213] In S20, the main MCU434 determines whether manual mode has been selected at mode switch 98. If manual mode is selected (YES), the process proceeds to S34 (see reference). Figure 36 If manual mode is not selected (in the case of NO), the process proceeds to S22.

[0214] In S22, the main MCU 434 determines whether automatic mode has been selected at mode switch 98. If automatic mode is selected (YES), the process proceeds to S72 (see reference). Figure 37 If the automatic mode is not selected (in the case of NO), the process proceeds to S24.

[0215] If neither manual nor automatic mode is selected at mode switch 98, that is, if parking mode is selected at mode switch 98, then process S24 is executed. In S24, the main MCU 434 sets the target travel speed V of the transport vehicle 2 to 0 km / h and the target rotation angle θ of the transport vehicle 2 to 0°. In S26, the main MCU 434 sends a power-on prohibition signal to the cutoff circuits 438, 440, and 442.

[0216] In S28, the main MCU434 calculates the rotation speed command values ​​for the right front wheel motor 232, the left front wheel motor 242, the right rear wheel motor 486, and the left rear wheel motor 492, and the steering angle command value for the steering motor 176 based on the target travel speed V and the target rotation angle θ.

[0217] In S30, the main MCU434 sends rotation speed command values ​​for the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, and left rear wheel motor 492, as well as steering angle command values ​​for the steering motor 176, to the motor MCUs 444, 446, 448, 450, and 452.

[0218] In S32, the main MCU 434 receives status signals from the motor MCUs 444, 446, 448, 450, and 452. After S32, processing returns to S2.

[0219] (Processing of the main MCU434 in manual mode)

[0220] With manual mode selected at mode switch 98, execute Figure 36 The process in S34 is shown below. In S34, the main MCU 434 determines whether the trigger switch 100 has been activated based on the input amount from the trigger switch 100. If the trigger switch 100 has been activated (in the case of YES), the process proceeds to S36. In S36, the main MCU 434 sends a power-on permission signal to the cutoff circuits 438, 440, and 442. After S36, the process proceeds to S46.

[0221] In S34, if the trigger switch 100 is not turned on (in the case of NO), the process proceeds to S38. In S38, the main MCU 434 sets the target travel speed V of the transport vehicle 2 to 0 km / h and the target rotation angle θ of the transport vehicle 2 to 0°.

[0222] In S40, the main MCU434 sends a power-on prohibition signal to the cut-off circuits 438, 440, and 442.

[0223] In S42, the main MCU 434 determines whether the braking circuit temperature T detected by thermistors 468e, 470e, 472e, and 474e is lower than the temperature protection release threshold T2. If the braking circuit temperature T is lower than the temperature protection release threshold T2 (YES case), the process proceeds to S44. If the braking circuit temperature T reaches or exceeds the temperature protection release threshold T2 in S42 (NO case), the process proceeds to S28 (see reference). Figure 35 ).

[0224] Manual mode is selected at mode switch 98, and the target travel speed V of transport vehicle 2 is set to 0 km / h. A power-on prohibition signal (i.e., transport vehicle 2 stops) is sent from the main MCU 434 to the cutoff circuits 438, 440, and 442. Furthermore, if the braking circuit temperature T is lower than the temperature protection release threshold T2, process S44 is executed. In S44, the main MCU 434 sets the temperature protection flag to 0. After S44, the process proceeds to S28 (see...). Figure 35 ).

[0225] In S46, the main MCU434 determines whether forward movement has been selected at the direction switching switch 102. If forward movement has been selected (if YES), the process proceeds to S48.

[0226] In S48, the main MCU434 determines whether the collision detection flag is 0. If the collision detection flag is 0 (YES), the process proceeds to S50.

[0227] In S50, the main MCU434 determines whether the overload monitoring flag is 0. If the collision monitoring flag is 0 (in the case of YES), the process proceeds to S52.

[0228] In S52, the main MCU434 determines whether the temperature protection flag is 0. If the temperature protection flag is 0 (YES), the process proceeds to S54.

[0229] In S54, the main MCU434 sets the upper limit travel speed of the transport vehicle 2 to the first upper limit travel speed (e.g., 5 km / h). After S54, processing proceeds to S58.

[0230] If the overload monitoring flag in S50 is 1 (in the case of NO), or if the temperature protection flag in S52 is 1 (in the case of NO), the process proceeds to S56. In S56, the main MCU 434 sets the upper limit travel speed of the transport vehicle 2 to a second upper limit travel speed (e.g., 1 km / h) that is lower than the first upper limit travel speed. After S56, the process proceeds to S58.

[0231] In S58, the main MCU434 determines the target travel speed V of the transport vehicle 2 based on the amount of the trigger switch 100 pressed. At this time, if the target travel speed V determined based on the amount of the trigger switch 100 pressed is above the upper limit travel speed set in S54 and S56, the main MCU434 makes the target travel speed V match the upper limit travel speed.

[0232] In S60, the main MCU434 determines the target rotation angle θ of the transport vehicle 2 based on the rotation angle of the handle shaft 84 input from the rotation angle sensor 88. After S60, processing proceeds to S28 (see reference). Figure 35 ).

[0233] If the collision detection flag in S48 is 1 (in the case of NO), the process proceeds to S62. With manual mode selected at mode switch 98, forward selected at travel direction switch 102, and the collision detection flag 1, the process in S62 is executed. In S62, the main MCU 434 sets the target travel speed V of the transport vehicle 2 to 0 km / h and the target turning angle θ of the transport vehicle 2 to 0°. In S64, the main MCU 434 sends a power-on prohibition signal to the cutoff circuits 438, 440, and 442. After S64, the process proceeds to S28 (see reference). Figure 35 ).

[0234] In S46, if reverse mode is selected at the travel direction switch 102 (in the NO case), the process proceeds to S66. If manual mode is selected at the mode switch 98 and reverse mode is selected at the travel direction switch 102, the process in S66 is executed. In S66, the main MCU 434 sets the upper limit travel speed of the transport vehicle 2 to the second upper limit travel speed (e.g., 1 km / h).

[0235] In S68, the main MCU 434 determines the target travel speed V of the transport vehicle 2 based on the amount of the trigger switch 100 pressed. At this time, if the target travel speed V determined based on the amount of the trigger switch 100 pressed is above the upper limit travel speed set in S66, the main MCU 434 makes the target travel speed V match the upper limit travel speed.

[0236] In S70, the main MCU434 determines the target rotation angle θ of the transport vehicle 2 based on the rotation angle of the handle shaft 84 input from the rotation angle sensor 88. After S70, processing proceeds to S28 (see reference). Figure 35 ).

[0237] Furthermore, the upper limit speed of the transport vehicle 2 in the S54 process can also be appropriately changed according to the operation of the speed switching switch 104. For example, when the transport vehicle 2 is set to high speed using the speed switching switch 104, the upper limit speed of the transport vehicle 2 can also be set to the first upper limit speed (e.g., 5 km / h). When the transport vehicle 2 is set to medium speed using the speed switching switch 104, the transport vehicle 2 can also be set to a third upper limit speed (e.g., 3 km / h) that is lower than the first upper limit speed and higher than the second upper limit speed. When the transport vehicle 2 is set to low speed using the speed switching switch 104, the transport vehicle 2 can also be set to a fourth upper limit speed (e.g., 1.5 km / h) that is lower than the third upper limit speed and higher than the second upper limit speed.

[0238] (Processing of the main MCU434 in automatic mode)

[0239] With automatic mode selected at mode switch 98, execute... Figure 37 The process in S72 is shown below. In S72, the main MCU434 determines whether the collision detection flag is 0. If the collision detection flag is 0 (YES), the process proceeds to S74.

[0240] In S74, the main MCU434 determines whether the overload monitoring flag is 0. If the collision monitoring flag is 0 (in the case of YES), the process proceeds to S76.

[0241] In S76, the main MCU434 sends a power-on permission signal to the cut-off circuits 438, 440, and 442.

[0242] In S78, the main MCU434 determines whether the temperature protection flag is 0. If the temperature protection flag is 0 (YES), the process proceeds to S80. In S80, the main MCU434 sets the upper limit travel speed of the transport vehicle 2 to the third upper limit travel speed (e.g., 3 km / h). After S80, the process proceeds to S84.

[0243] In S78, if the temperature protection flag is 1 (in the case of NO), the process proceeds to S82. In S82, the main MCU 434 sets the upper limit travel speed of the transport vehicle 2 to the second travel speed (e.g., 1 km / h). After S82, the process proceeds to S84.

[0244] In S84, the main MCU434 determines the target travel speed V of the transport vehicle 2 based on the instruction value from the automatic operation MCU430. At this time, if the target travel speed V determined based on the instruction value from the automatic operation MCU430 is above the upper limit travel speed set in S80 and S82, the main MCU434 makes the target travel speed V match the upper limit travel speed.

[0245] In S86, the main MCU434 determines the target rotation angle θ of the transport vehicle 2 based on the instruction value from the automatic operation MCU430. Following S86, processing proceeds to S28 (see reference). Figure 35 ).

[0246] If the collision detection flag is 1 in S72 (in the case of NO), or if the overload detection flag is 1 in S74 (in the case of NO), the process proceeds to S88. If automatic mode is selected at mode switch 98 and the collision detection flag is 1, or if automatic mode is selected at mode switch 98 and the overload detection flag is 1, the process in S88 is executed. In S88, the main MCU 434 sets the target travel speed V of the transport vehicle 2 to 0 km / h and the target rotation angle θ of the transport vehicle 2 to 0°. In S90, the main MCU 434 sends a power-on prohibition signal to the cutoff circuits 438, 440, and 442. After S90, the process proceeds to S28 (see reference). Figure 35 ).

[0247] (Processing performed by motor MCU444 and 446)

[0248] When the main power supply of the transport vehicle 2 is turned on, the motor MCUs 444 and 446 execute... Figure 38 , Figure 39 The processing shown.

[0249] like Figure 38 As shown, in S102, the motor MCUs 444 and 446 receive command signals from the main MCU 434.

[0250] In S104, the motor MCUs 444 and 446 determine the target rotation speed RS1 of the right front wheel motor 232 and the left front wheel motor 242 based on the instruction signal received from the main MCU 434.

[0251] In S106, the motor MCUs 444 and 446 determine the current rotational speed RS2 of the right front wheel motor 232 and the left front wheel motor 242 based on the detection signals received from the Hall sensors 482 and 484.

[0252] In S108, the motor MCUs 444 and 446 determine whether the target rotational speed RS1 determined in S104 is greater than the current rotational speed RS2 determined in S106. If the target rotational speed RS1 is greater than the current rotational speed RS2 (if YES), the process proceeds to S110.

[0253] In S110, motor MCUs 444 and 446 perform PWM control on the right front wheel motor 232 and the left front wheel motor 242 via motor drivers 454 and 456, accelerating the rotation of the right front wheel motor 232 and the left front wheel motor 242. Additionally, in S110, motor MCUs 444 and 446 input 0 as a current command value to the braking circuits 468 and 470 to disable the operation of the braking circuits 468 and 470.

[0254] In S112, the motor MCUs 444 and 446 determine the target rotational acceleration RA1 based on the difference between the target rotational speed RS1 determined in S104 and the current rotational speed RS2 determined in S106.

[0255] In S114, the motor MCUs 444 and 446 determine the current rotational acceleration RA2 based on the detection signals received from the Hall sensors 482 and 484.

[0256] In S116, motor MCUs 444 and 446 determine whether the target rotational acceleration RA1 determined in S112 is greater than the current rotational acceleration RA2 determined in S114. If the target rotational acceleration RA1 is greater than the current rotational acceleration RA2 (YES case), the process proceeds to S118. In S118, motor MCUs 444 and 446 increase the duty cycle in the PWM control of the right front wheel motor 232 and the left front wheel motor 242 performed by motor drivers 454 and 456. If the target rotational acceleration RA1 is less than the current rotational acceleration RA2 (NO case) in S116, the process proceeds to S120. In S120, motor MCUs 444 and 446 decrease the duty cycle in the PWM control of the right front wheel motor 232 and the left front wheel motor 242 performed by motor drivers 454 and 456. After S118 or S120, the process proceeds to S134 (see reference). Figure 39 ).

[0257] In S108, if the target rotational speed RS1 is lower than the current rotational speed RS2 (in the case of NO), the process proceeds to S122. In S122, the motor MCUs 444 and 446 reduce the rotation of the right front wheel motor 232 and the left front wheel motor 242 by means of the braking circuits 468 and 470. Additionally, in S122, the motor MCUs 444 and 446 disable the operation of the motor drivers 454 and 456.

[0258] In S124, the motor MCUs 444 and 446 determine the target rotational deceleration RD1 based on the difference between the target rotational speed RS1 determined in S104 and the current rotational speed RS2 determined in S106.

[0259] In S126, the motor MCUs 444 and 446 determine the current rotational deceleration RD2 based on the detection signals received from the Hall sensors 482 and 484.

[0260] In S128, motor MCUs 444 and 446 determine whether the target rotational deceleration RD1 determined in S124 is lower than the current rotational deceleration RD2 determined in S126. If the target rotational deceleration RD1 is lower than the current rotational deceleration RD2 (if YES), the process proceeds to S130. In S130, motor MCUs 444 and 446 increase the current command value for braking circuits 468 and 470. If, in S128, the target rotational deceleration RD1 is lower than the current rotational deceleration RD2 (if NO), the process proceeds to S132. In S132, motor MCUs 444 and 446 decrease the current command value for braking circuits 468 and 470. After S130 or S132, the process proceeds to S134 (see reference). Figure 39 ).

[0261] like Figure 39 As shown, in S134, the motor MCUs 444 and 446 determine whether the braking circuit temperature T detected by thermistors 468e and 470e exceeds the cooling start temperature T3. If the braking circuit temperature T exceeds the cooling start temperature T3 (in the case of YES), the process proceeds to S136. In S136, the motor MCUs 444 and 446 drive the cooling fans 50d and 52d to cool the electric braking circuit boards 50 and 52. After S136, the process proceeds to S138. If in S134 the braking circuit temperature T is below the cooling start temperature T3 (in the case of NO), the process proceeds to S138.

[0262] In S138, the motor MCUs 444 and 446 determine whether the braking circuit temperature T detected by thermistors 468e and 470e is lower than the cooling end temperature T4, which is lower than the cooling start temperature T3. If the braking circuit temperature T is lower than the cooling end temperature T4 (if YES), the process proceeds to S140. In S140, the motor MCUs 444 and 446 stop the cooling fans 50d and 52d to end the cooling of the electric braking circuit boards 50 and 52. After S140, the process proceeds to S142. If the braking circuit temperature T in S138 is higher than the cooling end temperature T4 (if NO), the process proceeds to S142.

[0263] In S142, the motor MCUs 444 and 446 send status signals to the main MCU 434. After S142, processing returns to S102 (see reference). Figure 38 ).

[0264] As described above, the motor MCUs 444 and 446 drive cooling fans 50d and 52d to cool the electric brake circuit boards 50 and 52 based on the brake circuit temperature T detected by thermistors 468e and 470e. With this configuration, the motor MCUs 444 and 446 can continuously apply braking to the right front wheel motor 232 and the left front wheel motor 242 via the brake circuits 468 and 470 for extended periods. For example, the motor MCUs 444 and 446 can continuously apply braking to the right front wheel motor 232 and the left front wheel motor 242 via the brake circuits 468 and 470 for more than 15 minutes, more specifically more than 30 minutes, and more specifically more than 1 hour.

[0265] (Processing performed by motor MCU448 and 450)

[0266] When the main power supply of the transport vehicle 2 is turned on, the motor MCU448 and 450 execute... Figure 40 , Figure 41 The processing shown.

[0267] like Figure 40 As shown, in S152, the motor MCUs 448 and 450 receive command signals from the main MCU 434.

[0268] In S154, the motor MCUs 448 and 450 determine the target rotation speed RS1 of the right rear wheel motor 486 and the left rear wheel motor 492 based on the instruction signal received from the main MCU 434.

[0269] In S156, the motor MCUs 448 and 450 determine the current rotational speed RS2 of the right rear wheel motor 486 and the left rear wheel motor 492 based on the detection signals received from the Hall sensors 488 and 494.

[0270] In S158, motor MCUs 448 and 450 determine whether the target rotational speed RS1 determined in S154 is above the lower limit rotational speed RS0. If the target rotational speed RS1 is above the lower limit rotational speed RS0 (in the case of YES), the process proceeds to S160. In S160, motor MCUs 448 and 450 disengage the right rear wheel electromagnetic brake 490 and the left rear wheel electromagnetic brake 496 using electromagnetic brake drivers 464 and 466. After S160, the process proceeds to S162. If the target rotational speed RS1 is below the lower limit rotational speed RS0 (in the case of NO), the process proceeds to S162.

[0271] In S162, the motor MCUs 448 and 450 determine whether the current rotational speed RS2, determined in S156, is below the lower limit rotational speed RS0. If the current rotational speed RS2 is below the lower limit rotational speed RS0 (if YES), the process proceeds to S164. In S164, the motor MCUs 448 and 450 activate the right rear wheel electromagnetic brake 490 and the left rear wheel electromagnetic brake 496 using the electromagnetic brake drivers 464 and 466. After S164, the process proceeds to S192 (see...). Figure 41 If the current rotational speed RS2 exceeds the lower limit rotational speed RS0 (in the case of NO), the process proceeds to S166.

[0272] In S166, the motor MCUs 448 and 450 determine whether the target rotational speed RS1 determined in S154 is greater than the current rotational speed RS2 determined in S156. If the target rotational speed RS1 is greater than the current rotational speed RS2 (if YES), the process proceeds to S168.

[0273] In S168, the motor MCUs 448 and 450 perform PWM control on the right rear wheel motor 486 and the left rear wheel motor 492 through the motor drivers 458 and 460 to accelerate the rotation of the right rear wheel motor 486 and the left rear wheel motor 492. Additionally, in S168, the motor MCUs 448 and 450 input 0 as a current command value to the braking circuits 472 and 474 to disable the operation of the braking circuits 472 and 474.

[0274] In S170, the motor MCUs 448 and 450 determine the target rotational acceleration RA1 based on the difference between the target rotational speed RS1 determined in S154 and the current rotational speed RS2 determined in S156.

[0275] In S172, the motor MCUs 448 and 450 determine the current rotational acceleration RA2 based on the detection signals received from the Hall sensors 488 and 494.

[0276] In S174, motor MCUs 448 and 450 determine whether the target rotational acceleration RA1 determined in S170 is greater than the current rotational acceleration RA2 determined in S172. If the target rotational acceleration RA1 is greater than the current rotational acceleration RA2 (YES case), the process proceeds to S176. In S176, motor MCUs 448 and 450 increase the duty cycle in the PWM control of the right rear wheel motor 486 and the left rear wheel motor 492 performed by motor drivers 458 and 460. If the target rotational acceleration RA1 is less than the current rotational acceleration RA2 (NO case) in S174, the process proceeds to S178. In S178, motor MCUs 448 and 450 decrease the duty cycle in the PWM control of the right rear wheel motor 486 and the left rear wheel motor 492 performed by motor drivers 458 and 460. After S176 or S178, the process proceeds to S192 (see reference). Figure 41 ).

[0277] In S166, if the target rotational speed RS1 is lower than the current rotational speed RS2 (in the case of NO), the process proceeds to S180. In S180, the motor MCUs 448 and 450 reduce the rotation of the right rear wheel motor 486 and the left rear wheel motor 492 by means of the braking circuits 472 and 474. Additionally, in S180, the motor MCUs 448 and 450 disable the operation of the motor drivers 458 and 460.

[0278] In S182, the motor MCUs 448 and 450 determine the target rotational deceleration RD1 based on the difference between the target rotational speed RS1 determined in S154 and the current rotational speed RS2 determined in S156.

[0279] In S184, the motor MCUs 448 and 450 determine the current rotational deceleration RD2 based on the detection signals received from the Hall sensors 488 and 494.

[0280] In S186, the motor MCUs 448 and 450 determine whether the target rotational deceleration RD1 determined in S182 is lower than the current rotational deceleration RD2 determined in S184. If the target rotational deceleration RD1 is lower than the current rotational deceleration RD2 (if YES), the process proceeds to S188. In S188, the motor MCUs 448 and 450 increase the current command value for the braking circuits 472 and 474. If in S186 the target rotational deceleration RD1 is lower than the current rotational deceleration RD2 (if NO), the process proceeds to S190. In S190, the motor MCUs 448 and 450 decrease the current command value for the braking circuits 472 and 474. After S188 or S190, the process proceeds to S192 (see reference). Figure 41 ).

[0281] like Figure 41 As shown, in S192, the motor MCUs 448 and 450 determine whether the braking circuit temperature T detected by thermistors 472e and 474e exceeds the cooling start temperature T3. If the braking circuit temperature T exceeds the cooling start temperature T3 (in the case of YES), the process proceeds to S194. In S194, the motor MCUs 448 and 450 drive the cooling fans 54d and 56d to cool the electric braking circuit boards 54 and 56. After S194, the process proceeds to S196. If in S192, the braking circuit temperature T is below the cooling start temperature T3 (in the case of NO), the process proceeds to S196.

[0282] In S196, the motor MCUs 448 and 450 determine whether the brake circuit temperature T, detected by thermistors 472e and 474e, is lower than the cooling end temperature T4. If the brake circuit temperature T is lower than the cooling end temperature T4 (YES case), the process proceeds to S198. In S198, the motor MCUs 448 and 450 stop the cooling fans 54d and 56d, thus ending the cooling of the electric brake circuit boards 54 and 56. After S198, the process proceeds to S200. If the brake circuit temperature T is higher than the cooling end temperature T4 in S196 (NO case), the process proceeds to S200.

[0283] In S200, the motor MCUs 448 and 450 send status signals to the main MCU 434. After S200, processing returns to S152 (see reference). Figure 40 ).

[0284] Figure 42 Examples illustrating the changes over time in the travel speed, braking current, and braking circuit temperature of the transport vehicle 2 when it is in manual mode on flat ground and downhill. Figure 42In the example shown, manual mode is selected at mode switch 98, and forward / backward mode is selected at forward switch. At time t1, when trigger switch 100 switches from off to on, the electromagnetic brake drivers 464 and 466 release the right rear wheel electromagnetic brake 490 and left rear wheel electromagnetic brake 496. Motor drivers 454, 456, 458, and 460 then drive the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, and left rear wheel motor 492, causing the transport vehicle 2 to begin moving forward. At time t2, when the transport vehicle 2 reaches its first upper limit speed, braking circuits 468, 470, 472, and 474 activate, applying electrical braking to the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, and left rear wheel motor 492. Even when the transport vehicle 2 moves downhill from flat ground, the speed of the transport vehicle 2 will be maintained at the first maximum speed due to the operation of braking circuits 468, 470, 472, and 474. Furthermore, the temperature of braking circuits 468, 470, 472, and 474 will rise when they are activated. When the temperature of braking circuits 468, 470, 472, and 474 exceeds the temperature protection threshold T1 at time t3, the maximum speed of the transport vehicle 2 switches from the first maximum speed to the second maximum speed, and braking circuits 468, 470, 472, and 474 apply stronger electrical braking to the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, and left rear wheel motor 492. Therefore, although the speed of the transport vehicle 2 decreases, the temperature of braking circuits 468, 470, 472, and 474 rises more rapidly. When the travel speed of the transport vehicle 2 decreases to the second upper limit travel speed at time t4, the braking circuits 468, 470, 472, and 474 weaken the electrical braking applied to the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, and left rear wheel motor 492. As a result, the temperature of the braking circuits 468, 470, 472, and 474 decreases. The temperature of the braking circuits 468, 470, 472, and 474 is below the temperature protection threshold T1. Even if it further decreases below the temperature protection release threshold T2, the temperature protection will not be released until the transport vehicle 2 stops, and the upper limit travel speed of the transport vehicle 2 is maintained at the second upper limit travel speed and remains unchanged. When the trigger switch 100 switches from on to off at time t5, the braking circuits 468, 470, 472, and 474 apply a stronger electrical braking action to the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, and left rear wheel motor 492. When the transport vehicle 2 stops at time t6, the temperature protection is released, and the upper limit speed of the transport vehicle 2 switches from the second upper limit speed to the first upper limit speed.Additionally, when the transport vehicle 2 stops at time t6, the electrical braking implemented by braking circuits 468, 470, 472, and 474 is terminated. Short-circuit braking is then implemented by motor drivers 454, 456, 458, and 460 for the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, and left rear wheel motor 492. Subsequently, the right rear wheel 252 and left rear wheel 272 are locked by the right rear wheel electromagnetic brake 490 and left rear wheel electromagnetic brake 496. After the electrical braking implemented by braking circuits 468, 470, 472, and 474 terminates, the temperature of braking circuits 468, 470, 472, and 474 decreases. Subsequently, when the trigger switch 100 switches from off to on again at time t7, the electromagnetic brake drivers 464 and 466 release the electromagnetic brakes 490 and 496 on the right and left rear wheels. The motor drivers 454, 456, 458, and 460 then drive the motors 232 on the right front wheel, 242 on the left front wheel, 486 on the right rear wheel, and 492 on the left rear wheel, causing the transport vehicle 2 to begin moving forward. When the transport vehicle 2 reaches its first maximum speed at time t8, the braking circuits 468, 470, 472, and 474 activate, applying electrical braking to the motors 232 on the right front wheel, 242 on the left front wheel, 486 on the right rear wheel, and 492 on the left rear wheel.

[0285] (Processing performed by the motor MCU452)

[0286] When the main power supply of the transport vehicle 2 is turned on, the motor MCU452 executes... Figure 43 The processing shown.

[0287] In S202, the motor MCU452 receives command signals from the main MCU434.

[0288] In S204, the motor MCU452 determines the target steering angle δ of the steering unit 10 based on the instruction signal received from the main MCU434.

[0289] In S206, the motor MCU452 determines the current steering angle γ of the steering unit 10 based on the detection signal received from the steering angle sensor 166.

[0290] In S208, the motor MCU452 determines whether the target steering angle δ determined in S204 is consistent with the current steering angle γ determined in S206. If the target steering angle δ is inconsistent with the current steering angle γ (in the case of NO), the process proceeds to S210.

[0291] In S210, the motor MCU452 determines the target rotational speed PR1 of the steering motor 176 based on the difference between the target steering angle δ determined in S204 and the current steering angle γ determined in S206.

[0292] In S212, the motor MCU 452 drives the steering motor 176 by means of PWM control performed by the motor driver 462, so that the steering motor 176 rotates at the target rotation speed PR1 determined in S210. After S212, the processing proceeds to S216.

[0293] If the target steering angle δ in S208 matches the current steering angle γ (in the case of YES), the process proceeds to S214. In S214, the motor MCU 452 applies short-circuit braking to the steering motor 176 via the motor driver 462. After S214, the process proceeds to S216.

[0294] In S216, the motor MCU452 sends a status signal to the main MCU434. After S216, processing returns to S202.

[0295] (Modified Example)

[0296] In the above embodiments, the right front wheel motor 232, the left front wheel motor 242, the right rear wheel motor 486, and the left rear wheel motor 492 can also be: in-wheel motors (not shown) assembled on the right front wheel 192, the left front wheel 212, the right rear wheel 252, and the left rear wheel 272.

[0297] In the above embodiments, the steering motor 176, the right front wheel motor 232, the left front wheel motor 242, the right rear wheel motor 486, and the left rear wheel motor 492 can be external rotor type brushless DC motors, brushed DC motors, AC motors, or other types of motors.

[0298] In the above embodiments, motor MCUs 444, 446, 448, 450, and 452 can also replace Hall sensors 482, 484, 488, 494, and 480, and use a circuit that detects the induced voltage of the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, left rear wheel motor 492, and steering motor 176 to detect the rotational speed of the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, left rear wheel motor 492, and steering motor 176.

[0299] In the above embodiments, it can also be configured to replace the front wheel unit 12 or the rear wheel unit 14, and move the transport vehicle 2 by means of a climbing unit, wherein the climbing unit includes: a drive wheel and a follower wheel arranged side by side, a belt mounted on the drive wheel and the follower wheel, and a motor for rotating the drive wheel.

[0300] In the above embodiments, the steering unit 10 may also be configured to replace the steering motor 176 with other types of actuators to rotate the steering shaft 168.

[0301] In the above embodiment, the bumper unit 16 is positioned at the front of the transport vehicle 2, and the collision monitoring switches 530 and 532 monitor collisions from the front of the transport vehicle 2. Alternatively, the bumper unit 16 can be positioned at the rear of the transport vehicle 2, and the collision monitoring switches 530 and 532 monitor collisions from the rear of the transport vehicle 2. Alternatively, two bumper units 16 can be positioned at the front and rear of the transport vehicle 2 respectively, with the collision monitoring switches 530 and 532 for each bumper unit 16 monitoring collisions from the front and rear of the transport vehicle 2 respectively. It is also possible that when the bumper unit 16 is positioned at the rear of the transport vehicle 2, and the collision monitoring switches 530 and 532 monitor collisions from the rear of the transport vehicle 2, and in… Figure 36 If S46 selects to move forward (in the case of YES), the process proceeds to S50; if S46 selects to move backward (in the case of NO), the process proceeds to S48; if the collision detection flag in S48 is 0 (in the case of YES), the process proceeds to S66; if the collision detection flag in S48 is 1 (in the case of NO), the process proceeds to S62.

[0302] In the above embodiments, the handlebar unit 8 may also include: a movable cam member 90, a fixed cam member 92, a coil spring 94, and a cover member (not shown) covering a portion of the handlebar shaft 84. In this case, the fixed member 82 may also constitute part of the cover member.

[0303] In the above embodiments, the handlebar unit 8 may also replace the coil spring 94 and have other types of elastic components. Additionally, the handlebar unit 8 may also include a shock absorber (not shown) that dampens the rotation of the handlebar shaft 84 by applying damping force.

[0304] In the above embodiments, although the overload monitoring sensors 320a, 320b, 320c, 320d, and 380 are described as optocouplers, they can also be light reflectors that detect the presence or absence of light reflected by the monitoring units 348a, 348b, 348c, 348d, and 416, magnetic sensors that detect the magnetic field from the magnets provided in the monitoring units 348a, 348b, 348c, 348d, and 416, or other types of non-contact monitoring sensors. Alternatively, the overload monitoring sensors 320a, 320b, 320c, 320d, and 380 can also be contact monitoring sensors.

[0305] In the above embodiments, although the switching elements 468a, 470a, 472a, and 474a of the braking circuits 468, 470, 472, and 474 are described as n-channel MOSFETs, these switching elements can also be p-channel MOSFETs, IGBTs, bipolar transistors, or other types of transistors. Alternatively, the switching elements 468a, 470a, 474a, and 472a can also be thyristors or other types of electronic variable resistors. The switching elements 468a, 470a, 472a, and 474a can be made of Si semiconductors, SiC semiconductors, GaN semiconductors, or other types of semiconductors.

[0306] As described above, in one or more embodiments, the transport vehicle 2 includes: a right front wheel 192, a left front wheel 212, a right rear wheel 252, and a left rear wheel 272 (examples of drive wheels); a right front wheel motor 232, a left front wheel motor 242, a right rear wheel motor 486, and a left rear wheel motor 492 (examples of motors), which rotate the right front wheel 192, left front wheel 212, right rear wheel 252, and left rear wheel 272; motor drivers 454, 456, 458, and 460 (examples of motor drive circuits), configured to drive the right front wheel motor 232, left front wheel motor 242, right rear wheel motor 486, and left rear wheel motor 492; a main MCU 434 and motor MCUs 444, 446, 448, and 450 (examples of control units), configured to drive the right front wheel motor 232 and left front wheel motor 242 by means of the motor drivers 454, 456, 458, and 460. 2. The right rear wheel motor 486 and the left rear wheel motor 492 are controlled to keep the travel speed of the transport vehicle 2 below the upper limit; and a trigger switch 100 (an example of an operating component) is provided on the transport vehicle 2 to accept operation by the user; the transport vehicle 2 can operate in manual mode and automatic mode. The manual mode is a mode in which the right front wheel motor 232, the left front wheel motor 242, the right rear wheel motor 486, and the left rear wheel motor 492 are driven when the trigger switch 100 is turned on, and the right front wheel motor 232, the left front wheel motor 242, the right rear wheel motor 486, and the left rear wheel motor 492 are stopped when the trigger switch 100 is turned off; the automatic mode is a mode in which the right front wheel motor 232, the left front wheel motor 242, the right rear wheel motor 486, and the left rear wheel motor 492 are driven regardless of whether the trigger switch 100 is turned on or off. The maximum speed limit in automatic mode (e.g., 3 km / h) is set to be lower than the maximum speed limit in manual mode (e.g., 5 km / h).

[0307] Based on the above configuration, since the upper limit of the travel speed of the transport vehicle 2 when operating in automatic mode is set to be lower than the upper limit of the travel speed of the transport vehicle 2 when operating in manual mode, the safety of the transport vehicle 2 when operating in automatic mode can be further improved.

[0308] In one or more embodiments, the transport vehicle 2 further includes overload monitoring sensors 320a, 320b, 320c, and 320d for detecting overload of goods. In automatic mode, when an overload is detected by the overload monitoring sensors 320a, 320b, 320c, and 320d, the transport vehicle 2 is prohibited from moving. In manual mode, the transport vehicle 2 is allowed to move even if an overload is detected by the overload monitoring sensors 320a, 320b, 320c, and 320d.

[0309] Based on the above configuration, in manual mode, the transport vehicle 2 is allowed to move even if an overload is detected, while in automatic mode, the transport vehicle 2 is prohibited from moving when an overload is detected. Therefore, the safety of the transport vehicle 2 when it operates in automatic mode can be further improved.

[0310] In one or more embodiments, the transport vehicle 2 further includes collision detection switches 530 and 532 (examples of collision detection sensors) for monitoring collisions with the transport vehicle 2 from the front. In automatic mode, when the transport vehicle 2 moves backward, if a collision is detected by the collision detection switches 530 and 532, the transport vehicle 2 is prohibited from moving. In manual mode, when the transport vehicle 2 moves backward, the transport vehicle 2 is allowed to move even if a collision is detected by the collision detection switches 530 and 532.

[0311] Based on the above configuration, in manual mode, even if a collision from the front of the transport vehicle 2 is detected when the transport vehicle 2 moves backward, the transport vehicle 2 is allowed to move. In automatic mode, if a collision from the front of the transport vehicle 2 is detected when the transport vehicle 2 moves backward, the transport vehicle 2 is prohibited from moving. Therefore, the safety of the transport vehicle 2 when it operates in automatic mode can be further improved.

[0312] In one or more embodiments, the transport vehicle 2 further includes collision detection switches 530 and 532 (examples of collision detection sensors) for monitoring collisions with the transport vehicle 2 from the rear. In automatic mode, when the transport vehicle 2 moves forward, if a collision is detected by the collision detection switches 530 and 532, the transport vehicle 2 is prohibited from moving. In manual mode, even if a collision is detected by the collision detection switches 530 and 532, the transport vehicle 2 is allowed to move forward.

[0313] Based on the above configuration, in manual mode, even if a collision from behind the transport vehicle 2 is detected when the transport vehicle 2 moves forward, the transport vehicle 2 is allowed to move. However, in automatic mode, if a collision from behind the transport vehicle 2 is detected when the transport vehicle 2 moves forward, the transport vehicle 2 is prohibited from moving. Therefore, the safety of the transport vehicle 2 when it operates in automatic mode can be further improved.

[0314] In one or more embodiments, the transport vehicle 2, in automatic mode, is capable of: tracking operation that moves in accordance with a beacon carried by a user, and remote control operation that moves in accordance with instructions from a remote control operated by the user.

[0315] Based on the above configuration, the safety of the transport vehicle 2 during automatic tracking operation and remote control operation can be further improved.

Claims

1. A transport vehicle, comprising: Drive wheel; A motor that drives the drive wheel to rotate; A motor drive circuit configured to drive the motor; The control unit is configured to control the motor via the motor drive circuit so that the travel speed of the transport vehicle is below the upper limit travel speed. An operating component, which is located on the transport vehicle, accepts operations performed by the user; as well as Overload monitoring sensors detect overloads. The transport vehicle can operate in a manual mode, where the motor drives when the operating component is engaged and stops when the operating component is disengaged. In the manual mode, when an overload is detected by the overload monitoring sensor, the transport vehicle is allowed to travel at a reduced maximum speed compared to when no overload is detected. The transport vehicle can also operate in an automatic mode, in which the motor is driven regardless of whether the operating components are on or off. The upper limit speed in automatic mode is set to be lower than the upper limit speed in manual mode. In the automatic mode, when an overload is detected by the overload monitoring sensor, the movement of the transport vehicle is prohibited.

2. The transport vehicle according to claim 1, characterized in that, The transport vehicle also includes a collision detection sensor to monitor collisions with vehicles from the front. In the automatic mode, when the transport vehicle is moving backward, if a collision is detected by the collision detection sensor, the transport vehicle's movement is prohibited. In the manual mode, the transport vehicle is allowed to move backward even if a collision is detected by the collision monitoring sensor.

3. The transport vehicle according to claim 1, characterized in that, The transport vehicle also includes a collision detection sensor to monitor collisions with vehicles from behind. In the automatic mode, when the transport vehicle is moving forward, if a collision is detected by the collision detection sensor, the transport vehicle's movement is prohibited. In the manual mode, the transport vehicle is allowed to move forward even if a collision is detected by the collision monitoring sensor.

4. The transport vehicle according to any one of claims 1 to 3, characterized in that, In the automatic mode, the transport vehicle is capable of performing: tracking operation to move in accordance with a beacon carried by the user, and remote control operation to move in accordance with instructions from a remote control operated by the user.

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