Automated guided vehicle, control device, control method, and program

Abstract

An automated guided vehicle (1) comprises: a vehicle body (11); a pair of drive wheels (12); a driven wheel (13); an electric motor (14); and a control device (20) that controls the electric motor (14). The control device (20) is provided with: a positional relationship acquisition unit; a target value determination unit; and a drive unit. The positional relationship acquisition unit obtains the positional relationship between the vehicle body (11) and a guide line (100). When the positional relationship is obtained, the target value determination unit determines, in accordance with the positional relationship, a target rotation speed of the electric motor (14) for aligning the vehicle body center axis AX1 with the guide line (100) while the automated guided vehicle 1 is made to move forward. When the positional relationship is not obtained, the target value determination unit determines, on the basis of the most recently obtained positional relationship, a target rotation speed of the electric motor (14) for causing the automated guided vehicle (1) to turn toward the guide line (100). The drive unit operates the electric motor (14) in accordance with the determined target rotational speeds.

Description

Automated guided vehicle, control device, control method, and program

[0001] This disclosure relates to an automated guided vehicle, a control device, a control method, and a program.

[0002] Automated guided vehicles (AGVs) are being introduced in warehouses, factories, and other facilities to improve the efficiency of logistics operations. Some AGVs recognize guide lines provided on the road surface and travel along these lines. An example of this type of AGV is disclosed in Patent Document 1. The AGV disclosed in Patent Document 1 detects the magnetic field created by guide lines composed of magnetic rods using a pair of magnetic sensors, and travels along a driving guide by controlling the steering angle of the steering wheels according to the difference in the detected values ​​of the sensors.

[0003] Japanese Patent Publication No. 2012-113377

[0004] The automated guided vehicle (AGV) disclosed in Patent Document 1 travels along a guide line by controlling the steering angle of the steering wheels in response to deviations from the guide line. However, due to unevenness or bumps in the road surface, deterioration of the guide line, high-speed turning maneuvers, etc., the orientation of the AGV's body may change significantly, causing it to deviate from the guide line. Specifically, the AGV may move to a position where the guide line is not included in the sensor's detection range. When the AGV deviates from the guide line in this way, it cannot automatically return to the guide line, so it is necessary to stop the AGV and manually return it to the guide line. As a result, the AGV's operational efficiency decreases.

[0005] This disclosure is made in view of the circumstances described above, and aims to provide an automated guided vehicle, a control device, a control method, and a program that can return to the guide line even if they deviate from it.

[0006] To achieve the above objective, the automated guided vehicle (AGV) according to this disclosure is an AGV that travels in accordance with a guide line provided on the road surface, and comprises a vehicle body, a pair of drive wheels, driven wheels, a pair of electric motors, and a control device. The pair of drive wheels are mounted on the vehicle body in a line aligned in the width direction of the vehicle body. The driven wheels are offset from the pair of drive wheels in the direction of travel of the AGV, and are mounted on the vehicle body at a position offset from the guide line and in contact with the road surface when the vehicle body's central axis, which is the central axis of the vehicle body extending in the direction of travel, is on the guide line. The pair of electric motors are driven by supplied power to rotate each of the drive wheels. The control device controls the electric motors based on image data indicating the condition of the road surface located below the vehicle body. The control device includes a position relationship acquisition unit, a target value determination unit, and a drive unit. The position relationship acquisition unit determines the positional relationship between the vehicle body and the guide line based on the image data. When the positional relationship is determined by the positional relationship acquisition unit, the target rotational speed of each motor, which is the target value for the rotational speed of each motor to move the automated guided vehicle forward and align the vehicle's central axis with the guide line, is determined according to the determined positional relationship. If the positional relationship cannot be determined by the positional relationship acquisition unit, the target rotational speed of each motor to rotate the automated guided vehicle toward the guide line is determined based on the positional relationship most recently determined by the positional relationship acquisition unit. The drive unit operates each of the motors according to the target rotational speed determined by the target value determination unit.

[0007] The automated guided vehicle (AGV) described herein, when the positional relationship between the vehicle body and the guide line cannot be determined, rotates the AGV toward the guide line based on the most recently determined positional relationship, thereby enabling it to return to the guide line even if it deviates from it.

[0008] Schematic diagram of the automated guided vehicle according to Embodiment 1 Block diagram showing the configuration of the control device according to Embodiment 1 Block diagram showing the hardware configuration of the control device according to Embodiment 1 Flowchart showing an example of the operation of the driving process performed by the control device according to Embodiment 1 Flowchart showing an example of the operation of the driving control process performed by the control device according to Embodiment 1 Diagram showing an example of image data when the automated guided vehicle according to Embodiment 1 is positioned on the guide line Diagram showing an example of image data when the automated guided vehicle according to Embodiment 1 is positioned off the guide line Diagram showing another example of image data when the automated guided vehicle according to Embodiment 1 is positioned off the guide line Diagram showing another example of image data when the automated guided vehicle according to Embodiment 1 is positioned off the guide line Diagram showing an example of the positional relationship between the vehicle body and the guide line in Embodiment 1 Diagram showing an example of image data when the automated guided vehicle according to Embodiment 1 is deviating from the guide line Flowchart showing an example of the operation of the guide line search process Schematic diagram of the automated guided vehicle according to Embodiment 2 Block diagram showing the configuration of the control device according to Embodiment 2 Flowchart showing an example of the operation of the travel control process performed by the control device according to Embodiment 2 Flowchart showing an example of the operation of the operation marker search process performed by the control device according to Embodiment 2 Flowchart showing an example of the operation of the operation control process performed by the control device according to Embodiment 2 Diagram showing an example of image data when the automated guided vehicle according to Embodiment 2 is positioned on the guide line Block diagram showing the configuration of the control device according to Embodiment 3 Flowchart showing an example of the operation of the travel control process performed by the control device according to Embodiment 3 Flowchart showing an example of the operation of the guide line search process performed by the control device according to Embodiment 3 Schematic diagram of a first modified example of the automated guided vehicle according to Embodiment 2 Schematic diagram of a second modified example of the automated guided vehicle according to Embodiment 2 Block diagram showing a modified example of the hardware configuration of the control device according to Embodiment 2

[0009] Hereinafter, the automated guided vehicle, control device, control method, and program according to the embodiments of this disclosure will be described in detail with reference to the drawings. In the drawings, the same or equivalent parts are denoted by the same reference numerals.

[0010] (Embodiment 1) Figure 1 is a schematic diagram showing the arrangement of components of an automated guided vehicle (AGV) 1 when viewed from above in the vertical direction. The AGV 1 shown in Figure 1 moves in factories, warehouses, etc., following guide lines 100 provided on the road surface 101. The guide lines 100 are made of a material that can be distinguished from the road surface 101 by image recognition, for example, a material whose color, reflectivity, etc., is different from the road surface 101 to the extent that it can be distinguished from the road surface 101 by image recognition.

[0011] The automated guided vehicle 1 comprises a vehicle body 11, a pair of drive wheels 12 attached to the vehicle body 11, a single driven wheel 13 attached to the vehicle body 11, a pair of electric motors 14 that rotate each of the drive wheels 12, and a control device 20 that controls each of the electric motors 14 based on image data indicating the state of the road surface 101 located below the vehicle body 11. In the example shown in Figure 1, the automated guided vehicle 1 further comprises a guide line detector 15 to acquire the state of the road surface 101 located below the vehicle body 11.

[0012] In Figure 1, the X-axis represents the width direction of the vehicle body 11, and the Y-axis represents the direction of travel of the automated guided vehicle (AGV) 1. In the example in Figure 1, the AGV 1 moves in the positive Y-axis direction. In other words, the positive Y-axis direction is the forward direction of travel, and the negative Y-axis direction is the backward direction of travel. The Z-axis is perpendicular to both the X-axis and the Y-axis. When the AGV 1 is positioned on a horizontal surface, the Z-axis extends vertically.

[0013] A pair of drive wheels 12 are mounted on the vehicle body 11, aligned in the X-axis direction. Each drive wheel 12 receives rotational force from its corresponding electric motor 14 and rotates independently of the others. The independent rotation of the drive wheels 12 makes it possible to adjust the direction of travel of the automated guided vehicle 1.

[0014] The driven wheel 13 is mounted on the vehicle body 11 with its axis of rotation extending parallel to the X-axis. The driven wheel 13 rotates in conjunction with the movement of the vehicle body 11 as the vehicle body 11 moves due to the rotation of the drive wheels 12. The driven wheel 13 is offset in the Y-axis direction from the pair of drive wheels 12 and is mounted on the vehicle body 11 at a position offset from the guide line 100 and in contact with the road surface 101 when the vehicle body central axis AX1, which is an axis that passes through the center of the vehicle body 11 in the X-axis direction and extends in the Y-axis direction, is on the guide line 100. The vehicle body central axis AX1 being on the guide line 100 means that the position through which the vehicle body central axis AX1 passes on the front end face of the vehicle body 11 in the direction of travel and the position through which the vehicle body central axis AX1 passes on the rear end face of the vehicle body 11 in the direction of travel are both located vertically above the guide line 100.

[0015] As described above, the driven wheel 13 attached to the vehicle body 11 is positioned offset from the guide wire 100 when the vehicle body's central axis AX1 is located on the guide centerline which passes through the center of the guide wire 100 in the width direction and extends in the direction of the guide wire 100's extension. Specifically, as shown in Figure 1, when the vehicle body's central axis AX1 is located on the guide centerline, the driven wheel 13 is positioned at a distance W1 from the guide wire 100. In other words, when the vehicle body's central axis AX1 is located on the guide centerline, the distance between the end of the driven wheel 13 closest to the guide wire 100 and the end of the guide wire 100 closest to the driven wheel 13 is W1. This prevents the driven wheel 13 from passing over the guide wire 100 when the automated guided vehicle 1 travels along the guide wire 100, thereby suppressing deterioration of the guide wire 100. As an example, the driven wheel 13 is attached to the vehicle body 11 at a position offset by the width of the guide wire 100 from the center of the vehicle body 11 in the X-axis direction.

[0016] Furthermore, it is preferable that the mounting position of the driven wheel 13 is offset in the Y-axis direction from the pair of drive wheels 12, and is offset by a distance corresponding to the width of the guide wire 100 from the center of the vehicle body 11 in the X-axis direction, and is determined based on the position of the center of gravity of the vehicle body 11.

[0017] The electric motors 14 are driven by the electric power supplied from the control device 20 to rotate the respective drive wheels 12. The output shafts of the electric motors 14 are respectively connected to the axles of the corresponding drive wheels 12. The electric motors 14 are controlled by the control device 20 independently of each other to rotate.

[0018] The guide line detector 15 is, for example, a vision sensor having a camera and performing image recognition processing on the captured data of the camera. The guide line detector 15 detects the guide line 100 from the captured data generated by a camera that captures the road surface located below the vehicle body 11. When the guide line detector 15 detects the guide line 100, it outputs the captured data with the guide center line added as image data to the control device 20, and when it does not detect the guide line 100, it outputs the captured data as image data to the control device 20.

[0019] The guide line detector 15 is provided in front of the traveling direction of the automated guided vehicle 1 with respect to the drive wheels 12 and the driven wheels 13. It is preferable that the guide line detector 15 is attached to the vehicle body 11 at a position where the center line extending in the vertical direction of the lens of the camera included in the guide line detector 15 is included in the plane including the vehicle body central axis AX1 and the Z axis.

[0020] The control device 20 controls each of the electric motors 14 based on the image data. As shown in FIG. 2, the control device 20 includes a position relationship acquisition unit 21 that obtains the position relationship between the vehicle body 11 and the guide line 100 based on the image data, a storage unit 22 that stores the obtained position relationship, and a target value determination unit 23 that determines the target rotational speed, which is the target value of the rotational speed of each of the electric motors 14, according to the position relationship between the vehicle body 11 and the guide line 100, and a drive unit 24 that operates each of the electric motors 14 according to the target rotational speed.

[0021] As shown in FIG. 3, as a hardware configuration for controlling each unit, the control device 20 includes a processor 81, a memory 82, and an interface 83. The processor 81, the memory 82, and the interface 83 are connected to each other by a bus 80. The processor 81 includes any electronic circuit including transistors and the like and is regarded as a circuit or a processor circuit.

[0022] Each function of the control device 20 is realized by software, firmware which is software incorporated in electronic equipment, or a combination of software and firmware. The software is described as a program and stored in the memory 82. By the processor 81 reading and executing the program stored in the memory 82, the functions of each part of the above-mentioned control device 20 are realized. That is, a program for executing the processing of the control device 20 is stored in the memory 82.

[0023] The memory 82 includes, for example, non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read-Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable and Programmable Read-Only Memory), magnetic disks, flexible disks, optical disks, compact disks, mini disks, DVDs (Digital Versatile Disc), etc.

[0024] The interface 83 connects the control device 20 to an external device and establishes communication. Specifically, the control device 20 is connected to each electric motor 14 and the induction line detector 15 via the interface 83. The interface 83 has a plurality of types of interface modules as required.

[0025] The control device 20 shown in FIG. 3 has one processor 81 and one memory 82 each, but the control device 20 may have a plurality of processors 81 and a plurality of memories 82. In this case, each function of the control device 20 may be realized by the cooperation of the plurality of processors 81 and the plurality of memories 82.

[0026] The operation of the control device 20 having the above configuration will be described. When the power is turned on, for example, the control device 20 performs initialization processing including confirmation of power-on to each part and starts the operation processing shown in FIG. The control device 20 continuously performs the operation processing of FIG. 4 while the power is on.

[0027] The control device 20 determines whether or not it has received instructions for the operation of the automated guided vehicle 1 from an operation unit, communication unit, or input unit (not shown) (step S11). For example, the control device 20 determines whether or not an operation start switch, stop switch, emergency stop switch, etc., on the operation unit has been operated. If the control device 20 has not received instructions for the operation of the automated guided vehicle 1 (step S11; No), it repeats the process of step S11.

[0028] When the control device 20 receives an instruction to operate the automated guided vehicle 1 (Step S11; Yes), it determines whether the received instruction indicates the start of operation (Step S12). If the received instruction does not indicate the start of operation (Step S12; No), the control device 20 stops the automated guided vehicle 1 (Step S13). Stopping the automated guided vehicle 1 includes maintaining the stopped state for the stopped automated guided vehicle 1.

[0029] As an example, when the stop switch on the control unit is operated, the control device 20 stops the automated guided vehicle 1 by limiting the rotation of the motor 14 while maintaining the power supply to the motor 14. Specifically, the target value determination unit 23 sets the target rotation speed to a sufficiently small value, and the drive unit 24 stops the motor 14 by supplying power to the motor 14 according to the target rotation speed. As a result, the automated guided vehicle 1 stops. As another example, when the emergency stop switch on the control unit is operated, the control device 20 stops the automated guided vehicle 1 by stopping the power supply to the motor 14. Specifically, the drive unit 24 stops the power supply to the motor 14 regardless of the target rotation speed. As a result, the automated guided vehicle 1 stops. When the processing in step S13 is completed, the control device 20 repeats the above processing from step S11.

[0030] If the acquired instruction indicates the start of operation (step S12; Yes), the control device 20 performs travel control of the automated guided vehicle 1 (step S14). If an error occurs during travel control (step S15; Yes), the control device 20 performs stop control to stop the automated guided vehicle (step S13). After the processing in step S13 is completed, the control device 20 repeats the above processing from step S11. When the automated guided vehicle 1 stops due to an error during travel control, it is preferable that the operation unit, communication unit, or input unit, etc., acquires a reset instruction to cancel the error stop before proceeding with the processing from step S11 onwards.

[0031] If the driving control is performed normally (step S15; No) and the automated guided vehicle 1 continues to move (step S16; No), the control device 20 repeats the above process from step S14. If the driving control is performed normally (step S15; No) and the automated guided vehicle 1 has stopped (step S16; Yes), the control device 20 repeats the above process from step S11.

[0032] The details of the driving control process in step S14 are described below. As described above, when the instruction acquired by the control device 20 indicates the start of operation, the control device 20 starts the driving control process shown in Figure 5. The position relationship acquisition unit 21 of the control device 20 acquires image data from the guide line detector 15 and determines whether or not the guide line 100, specifically the guide center line, is included in the image data (step S21).

[0033] Figure 6 shows an example of image data 31 acquired by the position relationship acquisition unit 21 from the guide line detector 15. The guide line detector 15 detects the guide lines 100 in the image data generated by the camera and adds a guide center line L1 that passes through the center of the detected guide line 100 in the width direction and extends in the direction of extension of the guide line 100 to generate image data 31. The image data 31 is generated with the front of the vehicle body 11 in the direction of travel positioned at the top. In Figure 6, the lower left vertex of the image data 31 is positioned at the origin and the bottom edge of the image data 31 is positioned on the x-axis in a coordinate plane that includes the x-axis extending horizontally and the y-axis extending vertically. In Figure 6, the guide lines 100 are shown in black and the guide center line L1 is shown as a white arrow.

[0034] As an example, the guide line detector 15 generates image data 31 as described above, detects the start and end points of the guide line 100 in the image data 31, and outputs the image data 31 and the coordinate information of the start and end points of the guide line 100 to the control device 20. In the example in Figure 6, in addition to the image data 31, the guide line detector 15 outputs the coordinate (x) of the start point P11 of the guide center line L1. １１ , y １１ ) and the coordinates (x) of the endpoint P12 of the guidance center line L1 １２ , y １２ The x component of the coordinates of the starting point P11 is output to the control device 20. The starting point is the rear end of the guide center line L1 in the direction of travel of the automated guided vehicle 1, and the ending point is the front end of the guide center line L1 in the direction of travel of the automated guided vehicle 1. In the example in Figure 6, since the vehicle body center axis AX1 of the vehicle body 11 is parallel to the guide center line L1, the x component of the coordinates of the starting point P11 is x １１ and the x component x of endpoint P12 １２ They match.

[0035] In the image data 31, the reference axis C1 extending in the y-axis direction from the center in the x-axis direction is shown by a dashed line. The reference axis C1 corresponds to the vehicle body central axis AX1. As in the example in Figure 6, when the reference axis C1 and the guide center line L1 coincide in the image data 31, the vehicle body central axis AX1 is located on the guide line 100, as shown in Figure 1.

[0036] In step S21 of FIG. 5, the position relationship acquisition unit 21 determines whether it has acquired the coordinate information of the start point and the end point of the guidance line 100 together with the image data from the guidance line detector 15. When the coordinate information of the start point and the end point of the guidance line 100 is acquired from the guidance line detector 15, it can be considered that the guidance line 100 is included in the image data 31. On the other hand, when the coordinate information of the start point and the end point of the guidance line 100 is not acquired from the guidance line detector 15, it can be considered that the guidance line 100 is not included in the image data 31. When the guidance line 100 is included in the image data 31 (step S21; Yes), the position relationship acquisition unit 21 obtains the position relationship between the vehicle body 11 and the guidance line 100 based on the image data 31 (step S22).

[0037] Details of step S22 will be described below. The position relationship acquisition unit 21 obtains the inclination angle θ1, which is the angle formed by the horizontal axis and the guidance line 100 in the image data 31 shown in FIG. 6, as the position relationship. Specifically, the horizontal axis in the image data 31 is the bottom side of the image data 31 on the x-axis. The magnitude of the angle formed by the horizontal axis and the guidance line 100 in the image data 31 is a right angle or an acute angle.

[0038] In the example of FIG. 6, the position relationship acquisition unit 21 uses the coordinates (x １１ , y １１ ) of the start point P11 of the guidance center line L1 and the coordinates (x １２ , y １２ ) of the end point P12 of the guidance center line L1 to obtain the inclination angle θ1, which is the angle formed by the x-axis where the bottom side of the image data 31 is located and the guidance center line L1, as the position relationship. In the example of FIG. 6, since the x component x １１ of the coordinates of the start point P11 and the x component x １２ of the end point P12 are the same, the inclination angle θ1 is a right angle.

[0039] Another example of the image data 31 is shown in FIG. 7. In the example of FIG. 7, the vehicle body central axis AX1 is displaced from the guidance line 100. In FIG. 7, the guidance center line L2 is indicated by a white arrow. At this time, the position relationship acquisition unit 21 uses the coordinates (x ２１ , y ２１ ) of the start point P21 of the guidance center line L2 and the coordinates (x ２２ , y２２ Based on this, the inclination angle θ2, which is the angle between the x-axis and the guidance center line L2 in the image data 31, is determined as the positional relationship. When the vehicle body central axis AX1 is offset from the guidance center line L2, the magnitude of the inclination angle θ2 is acute.

[0040] Figure 8 shows another example of image data 31. In the example in Figure 8, the vehicle body central axis AX1 is offset from the guide line 100 in the opposite direction to the example in Figure 7. In Figure 8, the guide center line L3 is indicated by a white arrow. At this time, the position relationship acquisition unit 21 obtains the coordinates (x) of the starting point P31 of the guide center line L3. ３１ , y ３１ ) and the coordinates (x) of the endpoint P32 of the guidance center line L3 ３２ , y ３２ Based on this, the inclination angle θ3, which is the angle between the x-axis and the guidance center line L3 in the image data 31, is determined as the positional relationship. When the vehicle body central axis AX1 is offset from the guidance center line L3, the magnitude of the inclination angle θ3 is acute.

[0041] To clearly indicate whether the automated guided vehicle 1 is deviated to the left or right relative to the guide line 100 in the direction of travel, the inclination angle θ2 when the automated guided vehicle 1 is facing left of the guide line 100 is represented as a positive value, as in the example in Figure 7, and the inclination angle θ3 when the automated guided vehicle 1 is facing right of the guide line 100 is represented as a negative value, as in the example in Figure 8.

[0042] Figure 9 shows another example of the image data 31. In the example in Figure 9, the vehicle body 11 is significantly deviated from the guide line 100 compared to the example in Figure 7. In Figure 9, the guide center line L4 is indicated by a white arrow. At this time, the position relationship acquisition unit 21 obtains the coordinates (x) of the starting point P41 of the guide center line L4. ４１ , y ４１ ) and the coordinates (x) of the endpoint P42 of the guidance center line L4 ４２ , y ４２ Based on this, the inclination angle θ4, which is the angle between the x-axis and the guidance center line L4 in the image data 31, is determined as the positional relationship. The magnitude of the inclination angle θ4 is smaller than the magnitude of the inclination angle θ2.

[0043] The position relationship acquisition unit 21 preferably determines the position relationship by determining the length in the extension direction of the guidance center line on the image data 31. In the example in Figure 6, the position relationship acquisition unit 21 determines the coordinates (x) of the starting point P11. １１ , y １１ ) and the coordinates (x) of the endpoint P12 １２ , y １２ Based on this, the length of the guide centerline L1 in the extension direction is determined. The same applies to the examples in Figures 7-9. Note that in the example in Figure 6, since the guide centerline L1 extends parallel to the y-axis, the length of the guide centerline L1 is ln1 = y １２ -y １１ This is the result.

[0044] The position relationship acquisition unit 21 preferably determines the position relationship by determining the distance between the starting point and ending point of the guide line 100 on the image data 31 and the reference axis C1 that extends vertically from the horizontal center on the image data 31.

[0045] In the example shown in Figure 6, the position relationship acquisition unit 21 calculates the distance between the starting point P11 and the ending point P12 and the reference axis C1. Since the guidance center line L1 coincides with the reference axis C1, the distance between the starting points d11 = 0, which is the distance between the starting point P11 and the starting point of the reference axis C1, and the distance between the ending points d12 = 0, which is the distance between the ending point P12 and the ending point of the reference axis C1. It is assumed that the position relationship acquisition unit 21 has pre-stored the coordinate information of the starting and ending points of the reference axis C1.

[0046] In the example shown in Figure 7, the position relationship acquisition unit 21 determines the distance between the starting point P21 and the ending point P22 and the reference axis C1. Specifically, the position relationship acquisition unit 21 determines the coordinates (x) of the starting point P21. ２１ , y ２１ ) and the coordinates (x) of the starting point Pc1 of the reference axis C1 ｃ１ , y ｃ１ Based on this, the distance between the starting points, d11 = x, is the distance between the starting point P21 and the starting point Pc1. ２１ -x ｃ１ Similarly, the position relationship acquisition unit 21 determines the coordinates (x) of the endpoint P22. ２２ , y ２２ ) and the coordinates (x) of the endpoint Pc2 of the reference axis C1 ｃ２ , y ｃ２ Based on this, the distance between endpoints d12 = x２２ -x ｃ２ We will find the answer. The same applies to the examples in Figures 8 and 9.

[0047] The position relationship acquisition unit 21 stores the position relationship obtained as described above in the storage unit 22. An example of a position relationship stored in the storage unit 22 is shown in Figure 10. As an example, the storage unit 22 stores the position relationship between the vehicle body 11 and the guide line 100 when the vehicle body 11 is positioned as shown in Figure 6, including the starting coordinates (x) of the guide center line L1. １１ , y １１ ), endpoint coordinates (x １２ , y １２ The inclination angle θ1, length ln1, distance d11 between starting points, and distance d12 between ending points are stored along with the time. The time is the time when the positional relationship is stored in the storage unit 22. Similarly, the positional relationship between the vehicle body 11 and the guide wire 100 when the vehicle body 11 is positioned as shown in Figures 7-9 is also stored in the storage unit 22.

[0048] As shown in Figure 5, the positional relationship acquisition unit 21 determines whether the length of the guide line 100 in the extension direction included in the positional relationship obtained in step S22, specifically, the length of the guide center lines L1-L4 in the extension direction, is greater than or equal to a first threshold (step S23). The first threshold is determined according to the size of the image data 31. As an example, the first threshold is set to 10% of the length of the image data 31 in the y-axis direction.

[0049] When the position relationship acquisition unit 21 determines that the length of the guide line 100 is greater than or equal to the first threshold (step S23; Yes), it determines whether the distance between the guide line 100 and the reference axis C1, which is included in the position relationship determined in step S22, is less than or equal to the second threshold (step S24). Specifically, the position relationship acquisition unit 21 determines whether the distance between the start point and end point of the guide line 100 and the reference axis C1 is less than or equal to the second threshold.

[0050] As an example, when the vehicle body 11 is positioned as shown in Figure 7, the position relationship acquisition unit 21 determines whether the distance between the starting points d21 and the distance between the ending points d22 are each less than or equal to the second threshold. When the distance between the starting points d21 and the distance between the ending points d22 are each less than or equal to the second threshold, the position relationship acquisition unit 21 determines that the distance between the guide line 100 and the reference axis C1 is less than or equal to the second threshold. On the other hand, when at least one of the distance between the starting points d21 and the distance between the ending points d22 is greater than the second threshold, the position relationship acquisition unit 21 determines that the distance between the guide line 100 and the reference axis C1 is greater than the second threshold. The second threshold is determined according to the distance between the vehicle body central axis AX1 and the guide line centerline when the vehicle body central axis AX1 can be considered to be aligned with the guide line 100. For example, the second threshold is the width of the guide line 100.

[0051] As shown in Figure 5, when the position relationship acquisition unit 21 determines that the distance between the guide line 100 and the reference axis C1 is less than or equal to the second threshold (step S24; Yes), the target value determination unit 23 performs straight-line control to determine the target rotational speed of each of the electric motors 14 for the automated guided vehicle 1 to move in a straight line (step S25). At this time, the target rotational speed of each of the electric motors 14 is the same value. The drive unit 24 operates each of the electric motors 14 according to the determined target rotational speed, causing the automated guided vehicle 1 to move in a straight line. In detail, the drive unit 24 converts power supplied from a power source (not shown) into power to be supplied to each of the electric motors 14 according to the target rotational speed, and supplies the converted power to each of the electric motors 14.

[0052] When the position relationship acquisition unit 21 determines that the distance between the guide line 100 and the reference axis C1 is greater than the second threshold (step S24; No), the target value determination unit 23 performs direction adjustment control to determine the target rotational speed of each electric motor 14 in order to move the automated guided vehicle 1 forward and align the vehicle's central axis AX1 with the guide line 100 (step S26). Specifically, the target value determination unit 23 determines the target rotational speed to position the vehicle's central axis AX1 on the guide line 100 parallel to the direction of extension of the guide line 100. In step S26, the drive unit 24 operates each of the electric motors 14 according to the determined target rotational speed, thereby adjusting the direction of the automated guided vehicle 1 and enabling the automated guided vehicle 1 to travel along the guide line 100.

[0053] The details of step S26 are described below. The target value determination unit 23 determines the target rotational speed of each motor 14 to guide the vehicle's central axis AX1 along the guide wire 100 while moving the automated guided vehicle 1 forward, according to the inclination angle. The target value determination unit 23 has in advance information about the rotational speed difference or rotational speed ratio of the motors 14 that changes according to the inclination angle. For example, the target value determination unit 23 has in advance a table that associates a range of inclination angles with the rotational speed difference or rotational speed ratio of the motors 14 corresponding to that range, a function that calculates the rotational speed difference or rotational speed ratio of the motors 14 using the inclination angle as a variable, etc. The rotational speed ratio of the motors 14 is, for example, the ratio of the rotational speed of the motor 14 with a higher rotational speed to the rotational speed of the motor 14 with a lower rotational speed among the motors 14.

[0054] Specifically, as the inclination angle approaches a right angle, the rotational speed difference of the electric motor 14 decreases. Conversely, as the inclination angle decreases, the rotational speed difference of the electric motor 14 increases. As a result, when the inclination angle is close to a right angle, that is, when the angle between the vehicle's central axis AX1 and the guide wire 100 is small, the rotational speed difference of the electric motor 14 is set to be small, thereby gradually adjusting the direction of travel of the automated guided vehicle 1. When the inclination angle is small, that is, when the angle between the vehicle's central axis AX1 and the guide wire 100 is large, the rotational speed difference of the electric motor 14 is set to be large, thereby abruptly adjusting the direction of travel of the automated guided vehicle 1.

[0055] The target value determination unit 23 determines the target rotational speed of each motor 14 based on the rotational speed difference or rotational speed ratio of the motors 14, which is determined according to the inclination angle as described above. In other words, the target rotational speed of each motor 14 is set to a different value. This makes it possible to adjust the direction of travel of the automated guided vehicle 1 toward the guide wire 100.

[0056] If the image data 31 does not contain the guide lines 100 (step S21; No), the process of determining the positional relationship in step S22 is not performed, and the target value determination unit 23 performs stop control to determine the target rotational speed for stopping each of the electric motors 14 (step S28). The automated guided vehicle 1 stops when the drive unit 24 operates each of the electric motors 14 according to the target rotational speed determined in step S28. As an example, the automated guided vehicle 1 stops when the target value determination unit 23 sets the target rotational speed to a sufficiently small value. Note that when the image data 31 does not contain the guide lines 100, this includes not only the case where the image data 31 does not contain the guide lines 100 at all, but also the case where, as shown in Figure 11, a part of the guide lines 100 is included, but the guide line detector 15 cannot recognize the guide lines 100, and therefore the image data 31 does not contain the guide center line.

[0057] As shown in Figure 5, when the position relationship acquisition unit 21 determines that the length of the guide wire 100 in the extension direction is less than a first threshold (step S23; No), it repeats the process from step S21 until a certain amount of time has elapsed since the start of the travel control process in Figure 5 (step S27; No). Whether or not a certain amount of time has elapsed is determined based on measurement by a timer (not shown), counting of the number of repetitions, etc. The certain amount of time should be set to be longer than the time required for the guide wire detector 15 to recognize the guide wire 100 and generate the image data 31.

[0058] If, after a certain period of time has elapsed since the start of the travel control process shown in Figure 5, the length of the guide wire 100 in the extension direction is less than the first threshold (step S27; Yes), the target value determination unit 23 performs stop control to determine the target rotational speed for stopping each of the electric motors 14 (step S28). The drive unit 24 operates each of the electric motors 14 according to the determined target rotational speed, thereby stopping the automated guided vehicle 1.

[0059] As described above, if the image data 31 does not include the guide wire 100, the processing in step S22 is not performed and the positional relationship cannot be determined, or if the length of the guide wire 100 in the extension direction is less than the first threshold, the control device 20 performs the stop processing in step S28 and then performs a guide wire search process to rotate the vehicle body 11 toward the guide wire 100 according to the positional relationship between the vehicle body 11 and the guide wire 100 most recently determined by the positional relationship acquisition unit 21 (step S29). If, as a result of the guide wire search process in step S29, a guide wire 100 with a length equal to or greater than the first threshold is detected (step S30; Yes), the processing from step S24 onwards described above is performed.

[0060] When steps S25 and S26 are completed, or when the guide wire search process in step S29 does not detect a guide wire 100 with a length equal to or greater than the first threshold (step S30; No), the control device 20 terminates the travel control process shown in Figure 5. Thereafter, as shown in Figure 4, the processes from step S15 onwards are carried out.

[0061] The details of the guide line search process in step S29 of Figure 5 are described below. As shown in Figure 5, when the image data 31 does not include the guide line 100, or when the length of the guide line 100 is less than the first threshold even after a certain amount of time has elapsed since the start of driving control, the control device 20 stops the automated guided vehicle 1 and starts the guide line search process shown in Figure 12. The guide line search process shown in Figure 12 is a process to return the automated guided vehicle 1, which has deviated from the guide line 100, back onto the guide line 100.

[0062] As shown in Figure 12, the position relationship acquisition unit 21 acquires the most recently determined position relationship stored in the storage unit 22 (step S31). More specifically, the position relationship acquisition unit 21 acquires the position relationship stored in the storage unit 22 that is associated with the most recent time. The data in the storage unit 22 that is associated with the most recent time corresponds to the position relationship most recently determined by the position relationship acquisition unit 21.

[0063] The target value determination unit 23 performs rotational control to determine the target rotational speed of each electric motor 14 for rotating the vehicle body 11 toward the guide wire 100, according to the inclination angle included in the positional relationship (step S32). According to the determined target rotational speed, the drive unit 24 operates each of the electric motors 14, causing the automated guided vehicle 1 to rotate toward the guide wire 100.

[0064] When the absolute value of the inclination angle is less than or equal to the reference angle, the difference in the target rotational speed of the electric motor 14 determined by the target value determination unit 23 is preferably greater than the difference in the target rotational speed of the electric motor 14 determined by the target value determination unit 23 when the absolute value of the inclination angle is greater than the reference angle.

[0065] As the difference in the target rotational speeds of the electric motors 14 increases, the difference between the actual rotational speed of one electric motor 14 and the actual rotational speed of the other electric motor 14 increases, causing the vehicle body 11 to turn sharply. In other words, when the absolute value of the inclination angle is less than or equal to the reference angle, the vehicle body 11 turns more sharply than when the absolute value of the inclination angle is greater than the reference angle. The reference angle is an angle that serves as a reference for switching the degree to which the vehicle body 11 turns, and can be determined arbitrarily. The reference angle is, for example, 45 degrees.

[0066] For example, if the absolute value of the inclination angle included in the positional relationship obtained in step S31 of Figure 12 is less than or equal to the reference angle, as shown by the inclination angle θ4 in Figure 9, the target value determination unit 23 sets the target rotational speed of one motor 14 to three times the target rotational speed of the other motor 14. In the example of Figure 9, since the automated guided vehicle 1 is facing left of the guide line 100, the target value determination unit 23 sets the target rotational speed of the motor 14 that drives the left drive wheel 12 in the forward direction of travel to three times the target rotational speed of the motor 14 that drives the right drive wheel 12 in the forward direction of travel. As a result, the automated guided vehicle 1, which has deviated from the guide line 100 by making a sharp turn to the right, can quickly return to the guide line 100.

[0067] On the other hand, if the absolute value of the inclination angle included in the positional relationship obtained in step S31 of Figure 12 is greater than the reference angle, as shown by the inclination angle θ2 in Figure 7, the target value determination unit 23 sets the target rotational speed of one motor 14 to twice the target rotational speed of the other motor 14. In the example of Figure 7, since the automated guided vehicle 1 is facing left of the guide line 100, the target value determination unit 23 sets the target rotational speed of the motor 14 that drives the left drive wheel 12 in the forward direction of travel to twice the target rotational speed of the motor 14 that drives the right drive wheel 12 in the forward direction of travel. As a result, the automated guided vehicle 1 turns more gently to the right than when the inclination angle included in the most recently determined positional relationship is θ4, making it possible for the automated guided vehicle 1, which has deviated from the guide line 100, to return to the guide line 100.

[0068] As described above, by performing rotational control according to the inclination angle, when the vehicle body's central axis AX1 is significantly deviated from the guide wire 100, it becomes possible to rotate the vehicle body 11 toward the guide wire 100 faster than when the deviation between the vehicle body's central axis AX1 and the guide wire 100 is small.

[0069] When the processing in step S32 is completed, the position relationship acquisition unit 21 acquires image data 31 from the guide wire detector 15 and determines whether or not the guide wire 100 is included in the image data 31 (step S33). The processing in step S33 is the same as the processing in step S21 in Figure 5.

[0070] If the image data 31 includes the guide wire 100 (step S33; Yes), the position relationship acquisition unit 21 determines the position relationship between the vehicle body 11 and the guide wire 100 based on the image data 31 (step S34). The process in step S34 is the same as the process in step S22 in Figure 5. The position relationship acquisition unit 21 determines whether the length of the guide wire 100 in the extension direction is greater than or equal to a first threshold (step S35). If the position relationship acquisition unit 21 determines that the length of the guide wire 100 is greater than or equal to the first threshold (step S35; Yes), it determines whether the distance between the guide wire 100 and the reference axis C1, which is included in the position relationship determined in step S34, is less than or equal to a second threshold (step S36). If the position relationship acquisition unit 21 determines that the distance between the guide wire 100 and the reference axis C1 is less than or equal to the second threshold (step S36; Yes), the target value determination unit 23 performs stop control to determine the target rotational speed for stopping each of the electric motors 14 (step S37). The automated guided vehicle 1 stops when the drive unit 24 operates each of the electric motors 14 according to the determined target rotation speed.

[0071] When the position relationship acquisition unit 21 determines that the distance between the guide line 100 and the reference axis C1 is greater than the second threshold (step S36; No), the above process is repeated from step S32. The inclination angle used in step S32 is included in the position relationship acquired in step S31. As a result, for example, when the position relationship determined in step S34 is the position relationship shown in Figure 9, the process of rotating the vehicle body 11 toward the guide line 100 is repeated. By repeating the process of rotating the vehicle body 11 in this way, for example, when the automated guided vehicle 1 rotates to the position shown in Figure 6, it is determined that the distance between the guide line 100 and the reference axis C1 is less than or equal to the second threshold, and the automated guided vehicle 1 stops. This prevents the automated guided vehicle 1 from deviating from the guide line 100 again immediately after the guide line search process is performed.

[0072] If the position relationship acquisition unit 21 determines that the length of the guide wire 100 is less than the first threshold (step S35; No), it repeats the process from step S32 until a certain amount of time has elapsed since the start of the guide wire search process in Figure 12 (step S38; No). The inclination angle used in step S32 is included in the position relationship acquired in step S31. If the length of the guide wire 100 is still less than the first threshold even after a certain amount of time has elapsed since the start of the process in Figure 12 (step S38; Yes), the position relationship acquisition unit 21 outputs an error (step S39). After the completion of step S39, as described above, the target value determination unit 23 performs stop control to determine the target rotational speed for stopping each of the electric motors 14 (step S37). The automated guided vehicle 1 stops when the drive unit 24 operates each of the electric motors 14 according to the determined target rotational speed.

[0073] When the process in step S37 is completed, the control device 20 terminates the guide line search process in Figure 12. After that, the processes from step S30 onwards are carried out as shown in Figure 5. If an error is output in step S39 in Figure 12, it is determined in step S15 in Figure 4 that an error has occurred in the travel control process in Figure 5 (step S15; Yes), and the control device 20 stops the automated guided vehicle 1 (step S13). After this, when the reset switch on the operating unit of the automated guided vehicle 1 is operated, the operation start switch, stop switch, emergency stop switch, etc. become operable.

[0074] As described above, when the guide line 100 is detected, specifically when the image data 31 contains a guide line 100 with a length equal to or greater than the first threshold, the automated guided vehicle 1 moves forward along the guide line 100, either in a straight line or while adjusting its direction. On the other hand, when the guide line 100 is not detected, specifically when the image data 31 does not contain a guide line 100, or when the length of the guide line 100 contained in the image data 31 is less than the first threshold, the vehicle rotates in the direction of the guide line 100. This makes it possible for the automated guided vehicle 1 to return to the guide line 100 even if it deviates from the guide line 100 due to, for example, unevenness in the road surface 101.

[0075] As described above, by performing the guide line search process according to the inclination angle, when the vehicle body's central axis AX1 is significantly deviated from the guide line 100, it becomes possible to rotate the vehicle body 11 toward the guide line 100 faster than when the deviation between the vehicle body's central axis AX1 and the guide line 100 is small. As a result, the unmanned transport vehicle 1 that has deviated from the guide line 100 can quickly return to the guide line 100.

[0076] Since the automated guided vehicle 1 can automatically return to the guide line 100 even if it deviates from it, the decrease in the operating rate of the automated guided vehicle 1 caused by manually returning the automated guided vehicle 1 to the guide line 100 is suppressed.

[0077] As described above, the automated guided vehicle (AGV) 1 has three wheels, specifically two drive wheels 12 and one driven wheel 13. In an AGV with four wheels, unevenness in the road surface 101 can cause one of the wheels to lift off the road surface and spin freely. If the drive wheels, steering wheels, or other wheels used to adjust the direction of the AGV spin freely, it becomes difficult to adjust the direction of the AGV toward the guide line 100. On the other hand, the AGV 1 according to Embodiment 1 has three wheels as described above, so even if there are unevenness in the road surface 101, both the drive wheels 12 and the driven wheel 13 will be in contact with the road surface 101 and will not spin freely. As a result, the AGV 1 can travel along the guide line 100 even if there are unevenness in the road surface 101.

[0078] (Embodiment 2) The configuration of the automated guided vehicle (AGV) is not limited to the example described above. Embodiment 2 describes an AGV 2 having a different configuration from the AGV 1 according to Embodiment 1. The AGV 2 shown in Figure 13 stops when it detects a stop marker 102 provided near the guide line 100 on the road surface 101, and after stopping, it reads the operation information indicated by the operation marker 103 and performs the operation indicated by the operation marker 103. In addition to the configuration of the AGV 1, the AGV 2 further includes a stop marker detector 16 for detecting the stop marker 102 and an operation marker detector 17 for reading the operation information indicated by the operation marker 103.

[0079] In the example shown in Figure 13, a pair of stop markers 102 are provided on either side of the guide wire 100. Although only a pair of stop markers 102 are shown in Figure 13, any number of stop markers 102 can be provided at any location. The stop markers 102 are formed to be distinguishable from the guide wire 100. For example, the stop markers 102 are made of the same material as the guide wire 100 and have a rectangular shape in which the shorter direction is parallel to the extension direction of the guide wire 100 and the longer direction is parallel to the width direction of the guide wire 100.

[0080] The operation marker 103 is provided near the stop marker 102. The operation marker 103 is formed from a two-dimensional code, a barcode, an RFID (Radio Frequency Identification) chip, a magnetic chip, etc. As an example of an RFID chip, an NFC (Near Field Communication) chip can be used. In the example in Figure 13, a pair of stop markers 102 are provided on either side of the guide line 100 before the corner of the guide line 100 which has a left turn path, and the operation marker 103 is provided near the stop markers 102, specifically near the stop marker 102 located to the right of the guide line 100 when facing the direction of travel of the automated guided vehicle 2. At this time, the operation marker 103 instructs the automated guided vehicle 2 to turn left as operation information.

[0081] The stop marker detector 16 is a sensor that detects the stop marker 102, and is, for example, a magnetic sensor, a vision sensor, etc. The stop marker detector 16 outputs the detection result to the control device 20.

[0082] The motion marker detector 17 is a sensor that detects the motion marker 103, and is, for example, a two-dimensional code reader, a barcode reader, an RFID reader, specifically an NFC reader, a magnetic sensor, etc. If the motion marker detector 17 cannot detect the motion marker 103, it outputs a detection result to the control device 20 indicating that it could not be detected. When the motion marker detector 17 detects the motion marker 103, it reads the motion information indicated by the motion marker 103. After reading the motion information, the motion marker detector 17 outputs a detection result to the control device 20 indicating the motion information read from the detected motion marker 103.

[0083] As shown in Figure 14, the configuration of the control device 20 according to Embodiment 2 is the same as that of the control device 20 according to Embodiment 1. However, the position relationship acquisition unit 21 and the target value determination unit 23 of the control device 20 acquire the detection results of the stop marker detector 16 and the operation marker detector 17. The hardware configuration of the control device 20 according to Embodiment 2 is the same as that of the control device 20 according to Embodiment 1. However, the control device 20 according to Embodiment 2 is connected to each motor 14, the induction line detector 15, each stop marker detector 16, and the operation marker detector 17 via the interface 83.

[0084] The automated guided vehicle 2, having the above configuration, performs the operation processing shown in Figure 4, similar to the automated guided vehicle 1. Details of the driving control performed by the automated guided vehicle 2 are shown in Figure 15. Similar to Embodiment 1, when the instruction acquired by the control device 20 indicates the start of operation, the control device 20 starts the driving control processing shown in Figure 15. When the detection result of the stop marker detector 16 indicates that no stop marker has been detected (step S41; No), the control device 20 performs the processing from step S21 onwards, which is the same processing as the driving control performed by the control device 20 according to Embodiment 1 shown in Figure 5.

[0085] As shown in Figure 15, when the stop marker detector 16 detects that a stop marker has been detected (step S41; Yes), the target value determination unit 23 performs stop control to determine the target rotational speed for stopping each of the electric motors 14 (step S42). The drive unit 24 operates each of the electric motors 14 according to the determined target rotational speed, thereby stopping the automated guided vehicle 2.

[0086] If the detection result of the motion marker detector 17 does not include motion information, in other words, if the motion marker detector 17 cannot read the motion information indicated by the motion marker 103 (step S43; No), the control device 20 performs a motion marker search process to search for the motion marker 103 (step S44). If the motion marker search process in step S44 is completed successfully (step S45; No), the control device 20 performs motion control to determine the target rotational speed of each motor 14 according to the motion information indicated by the motion marker 103 (step S46).

[0087] If the detection result of the motion marker detector 17 contains motion information, in other words, if the motion marker detector 17 reads the motion information indicated by the motion marker 103 (step S43; Yes), then the processes in steps S44 and S45 are not performed, and the control device 20 performs motion control to determine the target rotational speed of each motor 14 according to the motion information indicated by the motion marker 103 (step S46).

[0088] When the processes in steps S25, S26, and S46 are completed, if the guide wire search process in step S29 does not detect any guide wires 100 with a length equal to or greater than the first threshold (step S30; No), or if an error occurs in the operation marker search process in step S44 (step S45; Yes), the control device 20 terminates the travel control process shown in Figure 15. After that, the processes from step S15 onward are carried out as shown in Figure 4.

[0089] The details of the operation marker search process in step S44 of Figure 15 are described below. As shown in Figure 15, when the detection result of the operation marker detector 17 does not contain operation information, the control device 20 starts the operation marker search process shown in Figure 16.

[0090] If the operation marker detector 17 cannot detect the operation marker 103, it outputs a detection result to the control device 20 indicating that it could not detect the marker. If only a portion of the operation marker 103 is located within the detection range of the operation marker detector 17, the operation marker detector 17 will detect the operation marker 103, but will not be able to read the operation information because only a portion of the operation marker 103 is included in the detection range. In this case, the operation marker detector 17 will output a detection result to the control device 20 indicating that it detected the operation marker 103 but could not read the operation information.

[0091] As shown in Figure 16, the control device 20 repeats the process from step S53 onwards until a certain amount of time has elapsed since the start of the motion marker search process (step S51; No). When the detection result obtained from the motion marker detector 17 indicates that the motion marker 103 was detected but the motion information could not be read (step S53; Yes), the target value determination unit 23 performs low-speed reverse control to determine the target rotational speed of each motor 14 in order to move the automated guided vehicle 2 in reverse at a low speed and guide the vehicle's central axis AX1 along the guide line 100 (step S54). At this time, the magnitude of each target rotational speed of the motor 14 is smaller than the magnitude of each target rotational speed of the motor 14 when the automated guided vehicle 2 is moving forward. The drive unit 24 operates each of the motors 14 according to the determined target rotational speed, causing the automated guided vehicle 2 to move in reverse at a low speed.

[0092] If the detection result of the motion marker detector 17 does not include motion information, in other words, if the motion marker detector 17 cannot read the motion information indicated by the motion marker 103 (step S55; No), the target value determination unit 23 repeats the above process from step S51.

[0093] When the detection result obtained from the motion marker detector 17 indicates that the motion marker 103 could not be detected (step S53; No), the target value determination unit 23 performs direction adjustment control to determine the target rotational speed of each motor 14 in order to move the automated guided vehicle 2 forward while aligning the vehicle's central axis AX1 with the guide line 100 (step S56). The process in step S56 is the same as the process in step S26 shown in Figure 5. For example, if the stop marker 102 is detected but the motion marker 103 cannot be detected, the automated guided vehicle 2 stops before the position where it should stop according to the stop marker 102. Therefore, when the motion marker 103 cannot be detected, the automated guided vehicle 2 moves forward along the guide line 100. When the process in step S56 is completed, the target value determination unit 23 repeats the above process from step S51.

[0094] As a result of repeating the above process, if a certain amount of time has elapsed since the start of the operation marker search process in Figure 16 (step S51; Yes), the target value determination unit 23 outputs an error (step S52). In other words, even if a certain amount of time has elapsed since the start of the operation marker search process, the target value determination unit 23 outputs an error if the detection result obtained from the operation marker detector 17 indicates that the operation marker 103 could not be detected, or that the operation marker 103 was detected but the operation information could not be read.

[0095] When the process in step S52 is completed, or when the detection result of the operation marker detector 17 in step S55 contains operation information, in other words, when the operation marker detector 17 reads the operation information indicated by the operation marker 103 (step S55; Yes), the control device 20 terminates the operation marker search process shown in Figure 16. After that, the processes from step S45 onwards are carried out as shown in Figure 15.

[0096] The details of the operation control process in step S46 of Figure 15 are described below. As shown in Figure 15, when it is determined in step S43 that the detection result of the operation marker detector 17 contains operation information (step S43; Yes), or when the operation marker search process in step S44 is completed successfully (step S45; No), the control device 20 starts the operation control process shown in Figure 17.

[0097] The operation information indicated by the operation marker 103 is, for example, a turn indicating a left turn, a right turn, or a reverse turn, a stop, or forward movement indicating either forward movement at normal speed or forward movement at a slow speed. When the operation information indicates a reverse turn among the turns (step S61; turn, step S62; Yes), the target value determination unit 23 performs reverse control to determine the target rotational speeds of each of the electric motors 14 for reversing the automated guided vehicle 2 (step S63). The target value determination unit 23 is assumed to have in advance information about the rotational speed difference or rotational speed ratio of each of the target rotational speeds of the electric motors 14 for reversing the automated guided vehicle 2.

[0098] When the operation information indicates a left turn or a right turn within the turning process (step S61; turning, step S62; No), the position relationship acquisition unit 21 determines the position relationship between the vehicle body 11 and the guide line 100 based on the image data 31 (step S64). The process in step S64 is the same as the process in step S22 in Figure 5.

[0099] Figure 18 shows an example of image data 31 acquired by the position relationship acquisition unit 21 from the guide line detector 15. In Figure 18, the guide center line L5 is indicated by a white arrow. At this time, the position relationship acquisition unit 21 acquires the coordinates (x) of the starting point P51 of the guide center line L5. ５１ , y ５１ ) and the coordinates (x) of the endpoint P52 of the guidance center line L5 ５２ , y ５２ Based on this, the inclination angle θ5, which is the angle between the x-axis and the guidance center line L5 in the image data 31, is determined as the positional relationship. The positional relationship acquisition unit 21 further determines the length ln5 = y of the guidance center line L5 in the extension direction on the image data 31. ５２ -y ５１ We seek.

[0100] When the stop marker 102 is located before the bend in the guide wire 100, as shown in Figure 13, it is preferable for the automated guided vehicle 2 to proceed past the stop marker 102 to the bend, as shown in Figure 18, after stopping at the stop marker 102, and before performing the action instructed by the operation marker 103.

[0101] Therefore, the target value determination unit 23 determines whether the length of the guidance centerline included in the positional relationship determined in step S64 is greater than or equal to the third threshold (step S65). If the length of the guidance centerline L5 is greater than or equal to the third threshold (step S65: Yes), the target value determination unit 23 performs slow-speed control to determine the target rotational speed of each of the electric motors 14 for moving the automated guided vehicle 2 forward at a slow speed (step S66). In accordance with the target rotational speed determined in step S66, the drive unit 24 operates each of the electric motors 14, causing the automated guided vehicle 2 to move forward at a slow speed. The third threshold is determined according to the distance from the position where the automated guided vehicle 2 stops according to the stop marker 102 to the position suitable for starting the operation indicated by the operation marker 103. If the length of the guidance centerline L5 is greater than or equal to the third threshold, it means that the automated guided vehicle 2 has not reached a position suitable for turning left or right. When the processing in step S66 is completed, the control device 20 repeats the above processing from step S64.

[0102] When the length of the guidance center line L5 is less than the third threshold (step S65: No), the target value determination unit 23 performs left / right turn control to determine the target rotational speed of the electric motor 14 to turn the automated guided vehicle 2 left or right as indicated by the operation information (step S67).

[0103] When the processing in steps S63 and S67 is completed, the position relationship acquisition unit 21 performs the same processing as in steps S21-S26 and S28-S30 shown in Figure 5. As a result, after turning around, if the guide lines 100 that are equal to or greater than the first threshold are included in the image data 31, or if the guide lines 100 that are equal to or greater than the first threshold are detected as a result of the guide line search process, the automated guided vehicle 2 will travel along the guide lines 100. Also, if an error occurs in the guide line search process after turning around, the automated guided vehicle 2 will stop. This prevents the automated guided vehicle 2 from deviating from the guide lines 100 and continuing to travel.

[0104] When the operation information indicates a stop (step S61; stop), the target value determination unit 23 performs stop control to determine the target rotational speed for stopping each of the electric motors 14 (step S68). In accordance with the target rotational speed determined in step S68, the drive unit 24 operates each of the electric motors 14, causing the automated guided vehicle 2 to stop.

[0105] When the operation information indicates forward movement at a normal speed (step S61: forward movement, step S69: normal speed), the target value determination unit 23 performs normal forward control to determine the target rotational speed for moving the automated guided vehicle 2 forward at a normal speed (step S70). The target rotational speeds for each of the electric motors 14 determined in step S70 may be the same or different. The drive unit 24 operates each of the electric motors 14 according to the target rotational speeds determined in step S70, causing the automated guided vehicle 2 to move forward at a normal speed.

[0106] When the operation information indicates forward movement at a slow speed (step S61: forward, step S69: slow speed), the target value determination unit 23 performs slow-speed forward control to determine the target rotational speed for moving the automated guided vehicle 2 forward at a slow speed (step S71). The target rotational speeds for each of the electric motors 14 determined in step S71 may be the same or different. The drive unit 24 operates each of the electric motors 14 according to the target rotational speeds determined in step S71, causing the automated guided vehicle 2 to move forward at a slow speed.

[0107] When the processes in steps S25, S26, S68, S70, and S71 are completed, or when the guide wire search process in step S29 does not detect any guide wires 100 with a length equal to or greater than the first threshold (step S30; No), the control device 20 terminates the operation control process shown in Figure 17. After that, as shown in Figure 15, the control device 20 terminates the travel control process and then performs the processes from step S15 onwards as shown in Figure 4.

[0108] As described above, the automated guided vehicle 2 according to Embodiment 2 can perform the operation indicated by the operation marker 103. Furthermore, after the automated guided vehicle 2 turns around, control is performed to guide the automated guided vehicle 2 along the guide line 100 or to search for the guide line 100, thereby preventing the automated guided vehicle 2 from deviating from the guide line 100 and continuing to travel after turning around.

[0109] (Embodiment 3) The driving control processing performed by the control device 20 is not limited to the examples described above. Embodiment 3 describes a control device 40 that performs driving control processing different from that of the control device 20 in Embodiments 1 and 2. The configuration of the automated guided vehicle 1 on which the control device 40 according to Embodiment 3 is installed is the same as in Embodiment 1. The control device 40 shown in Figure 19 estimates the road surface condition, including at least one of the gradient and unevenness of the road surface 101, and controls the driving of the automated guided vehicle 1 according to the estimated road surface condition. In detail, in addition to the configuration of the control device 20, the control device 40 further includes a road surface condition estimation unit 25 that estimates the road surface condition and determines a correction amount to correct the rotational speed of the electric motor 14 according to the estimated road surface condition. The target value determination unit 23 determines the respective target rotational speeds of the electric motor 14 according to the positional relationship between the vehicle body 11 and the guide line 100 and the road surface condition. The hardware configuration of the control device 40 is the same as that of the control device 20.

[0110] The operation of the control device 40 having the above configuration will now be described. The control device 40 performs the driving process shown in Figure 4, similar to the control device 20. The details of the driving control process in step S14 of Figure 4 will be described below. When the instruction acquired by the control device 40 indicates the start of operation, the control device 40 starts the driving control process shown in Figure 20. The processes in steps S21 and S22 in Figure 20 are the same as the processes in steps S21 and S22 shown in Figure 5. After the positional relationship between the vehicle body 11 and the guide line 100 is determined in step S22, the road surface condition estimation unit 25 estimates the road surface condition (step S81).

[0111] The details of step S81 are described below. The road surface condition estimation unit 25 estimates the road surface condition by performing image analysis, specifically shading analysis, on the image data acquired from the guide line detector 15. As an example, under constant illumination conditions, the road surface condition estimation unit 25 uses the luminance gradient of each RGB (Red, Blue, Green) channel to detect abrupt changes in luminance between adjacent pixels in the image data, and uses local contrast to detect shaded areas or texture distortion in the image data.

[0112] "Under certain illumination conditions" means that the illumination (in lx) within the camera's shooting range of the guide line detector 15 is within a reference range suitable for estimating the road surface condition. A sudden change in brightness between adjacent pixels means that the difference in brightness between adjacent pixels exceeds a predetermined brightness difference threshold. The brightness difference threshold should be determined according to the values ​​that the brightness difference can take when the road surface 101 can be considered as a flat surface.

[0113] Shading analysis using local contrast divides image data into small regions, for example, 4x4 pixel regions, and determines whether each region is a flat region or a candidate for shading based on the local contrast obtained from the maximum brightness value Imax and the minimum brightness value Imin within the region. If the local contrast is C, then C = (Imax - Imin) / (Imax + Imin) holds true. If the local contrast is less than the contrast threshold, it is considered a flat region, and if the local contrast is equal to or greater than the contrast threshold, it is considered a candidate for shading. The contrast threshold should be determined according to the values ​​that the local contrast can take when the road surface 101 can be considered a flat surface.

[0114] The road surface condition estimation unit 25 determines whether the area is a flat area or a shaded area as described above, and then groups adjacent shaded area candidates. If the grouped shaded area candidates are equal to or greater than the reference area, the grouped shaded area candidates can be considered a shaded area. The reference area can be determined based on the wheel diameter of the automated guided vehicle 1, and the actual dimensions of one pixel according to the mounting height and field of view of the camera of the guide line detector 15. The camera mounting height is the distance between the camera mounting position and the road surface 101. As an example, when the wheel diameter is 200 mm, the width of the irregularities that affect the contact of the wheel is set to 1 / 10 of the wheel diameter, i.e., 20 mm. For example, when one pixel is 2 mm square, irregularities of 20 mm square correspond to 10 × 10 = 100 pixels. Therefore, the reference area can be set to 100 pixels. By making the reference area smaller, smaller irregularities can be detected, and by making the reference area larger, the influence of noise in the shaded area analysis can be reduced.

[0115] When the road surface 101 can be considered a flat surface, the local contrast of adjacent sub-regions is sufficiently close to each other. However, when the road surface 101 has irregularities or a gradient, irregular changes occur in the local contrast between adjacent sub-regions. Therefore, the road surface condition estimation unit 25 can detect texture distortion from the pattern of change in local contrast between adjacent sub-regions. In detail, the road surface condition estimation unit 25 calculates the difference in local contrast between adjacent sub-regions, and if the difference in local contrast is greater than or equal to the difference threshold, it detects that sub-region as distorted. The difference threshold should be determined according to the possible values ​​of the difference in local contrast between adjacent sub-regions when the road surface 101 can be considered a flat surface. The road surface condition estimation unit 25 can estimate the state of the road surface 101 from the distortion distribution pattern.

[0116] The road surface condition estimation unit 25 may perform shading analysis on image data using a CNN (Convolutional Neural Network). For example, shading analysis may be performed by extracting edges, textures, etc. in the first layer, recognizing shading patterns in the second layer, and automatically extracting only the shaded areas from the entire image in the third layer.

[0117] The road surface condition estimation unit 25 estimates the road surface condition by applying the detected sudden changes in brightness, as well as the geometric deformation which is the difference between the shadow pattern obtained from the detected shadow areas and texture distortions and the reference pattern, to a predetermined road surface condition estimation model, along with the camera mounting position and viewpoint, illumination conditions, etc. The reference pattern is the shadow pattern when the road surface 101 can be considered a flat surface, and can be predetermined based on test drives, simulations, etc.

[0118] Specifically, the road surface condition includes the difference in elevation between the left and right sides, the height of any steps located ahead in the direction of travel, and the gradient. For example, the difference in elevation between the left and right sides is obtained from the difference in brightness between a small area on the left edge and a small area on the right edge. The height of the steps is obtained from the difference in brightness between a small area corresponding to the top of the step and a small area corresponding to the bottom of the step, and from the relationship between the distance from the camera to the road surface 101 and the brightness. Note that the brightness of the small areas decreases as the distance from the camera to the road surface 101 increases.

[0119] A road surface condition estimation model can be generated by supervised learning following a neural network model. Supervised learning means that a learning device is given a large amount of input and output datasets, and the learning device learns the features in the large dataset and generates a model that estimates the result from the input. For example, a road surface condition estimation model can be generated by learning the brightness difference between adjacent pixels, geometric deformation, camera mounting position and viewpoint, and illumination conditions as input data, and the height difference between left and right, the height of the step ahead, and the gradient as output data.

[0120] As described above, after estimating the road surface condition, the road surface condition estimation unit 25 determines a correction amount to adjust the target rotational speed of the electric motor 14 according to the road surface condition (step S82). As an example, the road surface condition estimation unit 25 determines the correction amount α from the height difference Δh between the left and right sides based on the following equation (1). In the following equation (1), k1 is the proportionality constant (unit: % / mm). As an example, when Δh = 5 mm, using k1 = 0.2% / mm, a correction amount α = 1% / mm is obtained. α = k1・Δh ... (1)

[0121] The road surface condition estimation unit 25 determines the reliability of the process for estimating the road surface condition and determines whether the reliability is equal to or greater than a standard value (step S83). As an example, the road surface condition estimation unit 25 determines the reliability based on image quality and shadow detection accuracy. Image quality is determined based on whether the brightness is within an appropriate range, whether sufficient contrast is obtained, whether the noise is sufficiently low, etc., throughout the entire image data. Shadow detection accuracy is determined based on whether a clear shadow pattern is detected, whether the shadow boundaries are clear, etc. Image quality and shadow detection accuracy are evaluated on a value in the range of 0 or greater and 1 or less, and the average value of the evaluation value of image quality and the evaluation value of shadow detection accuracy is used as the reliability.

[0122] When the reliability is below a standard value (step S83; No), the road surface condition estimation unit 25 adjusts the correction amount according to the reliability (step S84). For example, when the reliability is less than a standard value, for example, 0.7, the road surface condition estimation unit 25 performs the process in step S84. In the process in step S84, if the reliability is 0.3 or greater and less than 0.7, the road surface condition estimation unit 25 sets the correction amount to 50%, and if the reliability is less than 0.3, it sets the correction amount to 0%. In this way, when the reliability is low, by reducing the absolute value of the correction amount, it is possible to reduce the influence of the correction amount on the determination of the target rotation speed. When the reliability is above a standard value (step S83; Yes), the process in step S84 is not performed.

[0123] The road surface condition estimation unit 25 stores the correction amount obtained as described above in the storage unit 22 and sends it to the target value determination unit 23. The processing in steps S23 and S24 is the same as the processing in steps S23 and S24 shown in Figure 5.

[0124] When the distance between the guide wire 100 and the reference axis C1 is less than or equal to the second threshold (step S24; Yes), the target value determination unit 23 performs straight-line control to determine the target rotational speed of each of the electric motors 14 in order to move the automated guided vehicle 1 in a straight line (step S85). Specifically, the target value determination unit 23 determines the target rotational speed by determining the same rotational speed for each of the electric motors 14 and correcting the determined rotational speeds based on the correction amount α.

[0125] For example, if there is a difference in height between the left and right sides of the road surface 101, with the left side being higher than the right side, the target value determination unit 23 determines the target rotational speeds for each of the motors 14 by decreasing the rotational speed of the motor 14 on the negative X-axis side by -α% and increasing the rotational speed of the motor 14 on the positive X-axis side by +α%. This cancels out the tilt of the vehicle body 11, improves the ground contact of the automated guided vehicle 1, and suppresses excessive steering.

[0126] As another example, when the road surface 101 has a steep gradient in the direction of travel and the automated guided vehicle 1 is located on the downhill road surface 101, the target value determination unit 23 can reduce the rotational speed of each of the electric motors 14, thereby suppressing the rapid acceleration of the automated guided vehicle 1.

[0127] When the distance between the guide wire 100 and the reference axis C1 is greater than the second threshold (step S24; No), the target value determination unit 23 performs direction adjustment control to determine the target rotational speed of each motor 14 in order to move the automated guided vehicle 1 forward and align the vehicle body central axis AX1 with the guide wire 100 (step S86). In detail, the target value determination unit 23 determines the target rotational speed by determining the rotational speed of each motor 14 according to the inclination angle and correcting the determined rotational speeds based on a correction amount α. The method of correction based on the correction amount α is the same as the process in step S85.

[0128] The processing in steps S27 and S28 is the same as the processing in steps S27 and S28 shown in Figure 5. When the image data 31 does not include the guide line 100, or when the length of the guide line 100 is less than the first threshold even after a certain amount of time has elapsed since the start of travel control, the control device 20 stops the automated guided vehicle 1 and starts the guide line search process shown in Figure 21 (step S87).

[0129] The process in step S31 shown in Figure 21 is the same as the process in step S31 shown in Figure 12. After the completion of the process in step S31, the road surface condition estimation unit 25 performs the processes in steps S81-S84. The processes in steps S81-S84 are the same as the processes in steps S81-S84 shown in Figure 20. The target value determination unit 23 performs rotational control to determine the target rotational speed of each electric motor 14 for rotating the vehicle body 11 toward the guide wire 100, according to the inclination angle included in the positional relationship (step S88). In detail, the target value determination unit 23 determines the target rotational speed by determining the rotational speed of each electric motor 14 according to the inclination angle and correcting the determined rotational speed based on a correction amount α. The method of correction based on the correction amount α is the same as the process in step S85 shown in Figure 20. The processes in steps S33-S39 are the same as the processes in steps S33-S39 shown in Figure 12.

[0130] As described above, the control device 40 mounted on the automated guided vehicle 1 according to Embodiment 3 estimates the road surface condition and uses the road surface condition as feedback to control the driving of the automated guided vehicle 1. This makes it possible to improve driving stability compared to the case where driving control is performed based only on the positional relationship between the vehicle body 11 and the guide line 100.

[0131] Furthermore, when the reliability of the process for estimating road surface conditions is below a standard value, the stability of the automated guided vehicle 1 during operation can be improved by reducing the absolute value of the correction amount.

[0132] This disclosure is not limited to the embodiments described above. The configuration of the automated guided vehicle (AGV) is not limited to the examples described above. For example, in the examples of embodiments 1-3, the AGVs 1 and 2 mainly move forward with the location where the guide line detector 15 is attached to the vehicle body 11 as the front of the direction of travel, but the AGV may move in both directions. The AGV 3 shown in Figure 22 further includes a guide line detector 15 in addition to the configuration of the AGV 1. By providing guide line detectors 15 at both ends in the direction of travel, the AGV 3 can move in both directions. The AGV 3 may also include a guide line detector 15 in addition to the configuration of the AGV 2.

[0133] As another example, in the example of Embodiment 1-3, the driven wheel 13 is mounted on the vehicle body 11 at a position offset to the left of the vehicle body central axis AX1 with respect to the direction of travel, but it may also be mounted on the vehicle body 11 at a position offset to the right of the vehicle body central axis AX1 with respect to the direction of travel.

[0134] As another example, in the example of Embodiment 1-3, the driven wheel 13 is mounted in front of the drive wheel 12 in the direction of travel, but it may also be mounted behind the drive wheel 12 in the direction of travel.

[0135] The mounting position of the camera on the guide wire detector 15 is not limited to the above example, but can be any position that allows it to photograph the road surface 101 below the vehicle body 11.

[0136] The configuration of the control devices 20 and 40 is not limited to the examples described above. For example, the control devices 20 and 40 may include at least one of the induction line detector 15, the stop marker detector 16, and the operation marker detector 17. As another example, when the control devices 20 and 40 receive an operation start instruction, stop instruction, emergency stop instruction, etc. from an external device via a communication unit or input unit, they may perform subsequent processing from step S11 in Figure 4 according to the instruction.

[0137] The shape of the vehicle body 11 is not limited to the above example, and can be any shape that can accommodate the components of the automated guided vehicle 1.

[0138] The configuration of the guide wire 100 is not limited to the example described above. For example, the color of the guide wire 100 can be any color as long as the guide wire detector 15 can distinguish the guide wire 100 from the road surface 101, and the width of the guide wire 100 can be any width as long as it can be detected by the guide wire detector 15. As another example, the guide wire 100 is not limited to the right-angle bend shown in Embodiment 2, but may have an arc-shaped bend.

[0139] The relative positional relationship between the stop marker 102 and the operation marker 103 is not limited to the example described above; it is sufficient if the positional relationship allows the automated guided vehicle 2, which has stopped after reading the stop marker 102, to read the operation marker 103. As an example, as shown in Figure 23, the operation marker 103 may be positioned further forward in the direction of travel of the automated guided vehicle 4 than the stop marker 102. In this case, the operation marker detector 17 of the automated guided vehicle 4 should be mounted on the vehicle body 11 further forward in the direction of travel than the stop marker detector 16.

[0140] The stop marker 102 is not limited to the examples described above and can be any type as long as it is distinguishable from the guide wire 100. For example, the stop marker 102 may be formed from tape that differs from the guide wire 100 in at least one of its color and reflectivity. As another example, the stop marker 102 may be formed from magnetic tape. In this case, the stop marker detector 16 can be formed from a magnetic sensor. Furthermore, the operation information indicated by the operation marker 103 is not limited to the examples described above and can be any type.

[0141] The configuration of the stop marker detector 16 and the operation marker detector 17 is not limited to the example described above. For example, the control device 20 may be equipped with only one stop marker detector 16. As another example, the operation marker detector 17 may be mounted on the vehicle body 11 at a position offset to the left of the vehicle body central axis AX1, facing the direction of travel of the automated guided vehicle 2. In this case, the operation marker 103 should be provided to the left of the guide wire 100, facing the direction of travel of the automated guided vehicle 2.

[0142] The position relationship acquisition unit 21 may determine whether a line matching the color of the guidance center line L1 is included in a region of color matching the color of the guidance line 100. In this case, the position relationship acquisition unit 21 is assumed to have pre-stored information about the colors of the road surface 101, the guidance line 100, and the guidance center line L1. The colors of the guidance center lines L1, L2, L3, L4, and L5 are arbitrary as long as the position relationship acquisition unit 21 can distinguish them from the guidance line 100. Also, the guidance center lines L1, L2, L3, L4, and L5 are not limited to arrows and may be represented by line segments.

[0143] The position relationship acquisition unit 21 may determine the angle between the guide centerlines L1, L2, L3, L4, L5 and the reference axis C1 as the inclination angle. In this case, the rotational speed difference or rotational speed ratio of the motor 14 when the inclination angle is less than the reference angle is smaller than the rotational speed difference or rotational speed ratio of the motor 14 when the inclination angle is equal to or greater than the reference angle.

[0144] The sign of the tilt angle determined by the position relationship acquisition unit 21 may differ from that of embodiments 1 and 2. Specifically, the tilt angle θ2 shown in Figure 7 may be shown as a negative value, and the tilt angle θ3 shown in Figure 8 may be shown as a positive value.

[0145] The target value determination unit 23 is not limited to the inclination angles of the guidance centerlines L1, L2, L3, L4, and L5, but may also determine the target rotational speed of each motor 14 based on the coordinates of the start and end points of the guidance centerlines L1, L2, L3, L4, and L5. Furthermore, if the road surface condition cannot be obtained from the road surface condition estimation unit 25, the target value determination unit 23 may use the most recently estimated road surface condition stored in the storage unit 22.

[0146] The road surface condition estimation process performed by the road surface condition estimation unit 25 is not limited to the above example, and any process that estimates the road surface condition including at least one of the gradient and unevenness of the road surface 101 is acceptable. For example, the road surface condition estimation unit 25 may acquire photographic data from a camera independent of the guide line detector 15 and estimate the road surface condition from the acquired photographic data.

[0147] As another example, the road surface condition estimation unit 25 may estimate the road surface condition by directly measuring the distance to the road surface 101 using a stereo camera, structured light illumination, a Time of Flight (ToF) sensor, etc. By directly measuring the distance to the road surface 101, the road surface condition can be estimated with greater accuracy. In this case, as in Embodiment 3, the reliability of the road surface condition estimation process can be determined, and the correction amount can be adjusted according to the reliability. The road surface condition estimation unit 25 may also correct errors in the distance measurement result caused by at least one of the attitude and movement of the vehicle body 11, based on the measurement result of a gyro sensor attached to the vehicle body 11. The attitude of the vehicle body 11 is expressed as angular velocity or angular fluctuation. By correcting errors in the distance measurement result, the robustness of the road surface condition estimation process can be improved.

[0148] Furthermore, the hardware configuration and flowchart described above are examples only and can be changed and modified as needed.

[0149] As an example, a modified hardware configuration of the control device 20 is shown in Figure 24. The control device 20 may be implemented using a processing circuit 84, as shown in Figure 24. The same applies to the control device 40. The processing circuit 84 of the control device 20 shown in Figure 24 is connected to the electric motor 14 and the induction wire detector 15 via an interface circuit 85.

[0150] If the processing circuit 84 is dedicated hardware, the processing circuit 84 may be, for example, a single circuit, a composite circuit, a processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. Each part of the control device 20 may be implemented by an individual processing circuit 84, or each part of the control device 20 may be implemented by a common processing circuit 84.

[0151] Some functions of the control devices 20 and 40 may be implemented by dedicated hardware, while other functions may be implemented by software or firmware. For example, in the control device 20, the drive unit 24 may be implemented by the processing circuit 84 shown in Figure 24, and the position relationship acquisition unit 21, the storage unit 22, and the target value determination unit 23 may be implemented by the processor 81 shown in Figure 3 reading and executing a program stored in the memory 82.

[0152] A control device 20 that performs the above-described operations may be realized by distributing a computer-readable recording medium such as a flexible disk, CD-ROM (Compact Disc-Read Only Memory), or DVD-ROM (Digital Versatile Disc-Read Only Memory) containing a computer program for performing the above-described operations, and then installing the computer program on a computer. Alternatively, a control device 20 that performs the above-described operations may be realized by a dedicated system. The computer program may be superimposed on a carrier wave and provided via a communication network.

[0153] This application is based on Japanese Patent Application No. 2025-10039, filed on 23 January 2025. The entire specification, claims, and drawings of Japanese Patent Application No. 2025-10039 are incorporated herein by reference.

[0154] 1, 2, 3, 4 Automated Guided Vehicle, 11 Vehicle Body, 12 Drive Wheels, 13 Driven Wheels, 14 Electric Motor, 15 Guide Line Detector, 16 Stop Marker Detector, 17 Motion Marker Detector, 20, 40 Control Device, 21 Position Relationship Acquisition Unit, 22 Memory Unit, 23 Target Value Determination Unit, 24 Drive Unit, 25 Road Surface Condition Estimation Unit, 31 Image Data, 80 Bus, 81 Processor, 82 Memory, 83 Interface, 84 Processing Circuit, 85 Interface Circuit, 100 Guide Line, 101 Road Surface, 102 Stop Marker, 103 Motion Marker, AX1 Vehicle Body Center Axis, C1 Reference Axis, L1, L2, L3, L4, L5 Guide Center Lines, Pc1, P11, P21, P31, P41, P51 Starting point: Pc2, P12, P22, P32, P42, P52 Ending point: W1 Interval: θ1, θ2, θ3, θ4, θ5 Inclination angle.

Claims

1. An automated guided vehicle that travels along a guide line provided on the road surface, comprising: a vehicle body; a pair of drive wheels mounted on the vehicle body in the width direction of the vehicle body; driven wheels mounted on the vehicle body at a position offset from the guide line and in contact with the road surface when the vehicle body's central axis, which is the central axis of the vehicle body extending in the direction of travel, is on the guide line; a pair of electric motors that rotate each of the drive wheels by being driven by supplied power; and a control device that controls the electric motors based on image data indicating the condition of the road surface located below the vehicle body, wherein the control device comprises: a position relationship acquisition unit that determines the position relationship between the vehicle body and the guide line based on the image data, An automated guided vehicle (AGV) having: when the position relationship is determined by the position relationship acquisition unit, a target rotational speed is determined, which is a target value for the rotational speed of each of the electric motors for moving the AGV forward and aligning the vehicle's central axis with the guide line, according to the determined position relationship; when the position relationship is not determined by the position relationship acquisition unit, a target value determination unit that determines the target rotational speed of each of the electric motors for rotating the AGV toward the guide line based on the position relationship most recently determined by the position relationship acquisition unit; and a drive unit that operates each of the electric motors according to the target rotational speed determined by the target value determination unit.

2. The position relationship acquisition unit determines the inclination angle, which is the angle between the horizontal axis and the guide line in the image data, as the position relationship, and the target value determination unit determines the target rotational speed of each of the electric motors according to the inclination angle, as described in claim 1.

3. The automated guided vehicle according to claim 2, wherein, when the positional relationship acquisition unit obtains the inclination angle, the target value determination unit determines the target rotational speed of each of the electric motors for moving the automated guided vehicle forward while aligning the vehicle's central axis with the guide line, according to the inclination angle.

4. The automated guided vehicle according to claim 2 or 3, wherein, if the position relationship acquisition unit has not been able to determine the inclination angle, the target value determination unit determines the target rotational speed of each of the electric motors according to the inclination angle most recently determined by the position relationship acquisition unit.

5. The unmanned transport vehicle according to claim 4, wherein, when the absolute value of the inclination angle most recently obtained by the position relationship acquisition unit is less than or equal to the reference angle, the difference in the target rotational speed of the electric motor determined by the target value determination unit is greater than the difference in the target rotational speed of the electric motor determined by the target value determination unit when the absolute value of the inclination angle is greater than the reference angle.

6. The position relationship acquisition unit determines the length of the guide line in the extension direction in the image data as the position relationship; the target value determination unit determines the target rotation speed of each of the electric motors for moving the vehicle body along the guide line while advancing the automated guided vehicle when the length of the guide line in the extension direction is equal to or greater than a first threshold; and when the length of the guide line in the extension direction is less than a first threshold, or when the position relationship acquisition unit has not determined the position relationship, the target rotation speed of each of the electric motors for rotating the vehicle body toward the guide line is determined based on the position relationship most recently determined by the position relationship acquisition unit; the automated guided vehicle according to any one of claims 1 to 5.

7. The position relationship acquisition unit determines the distance between the starting point of the guide line and the ending point of the guide line, which is located in front of the starting point in the direction of travel, in the image data, and a reference axis that extends vertically from the horizontal center in the image data, as the position relationship; the target value determination unit determines the target rotational speed of each of the electric motors for moving the automated guided vehicle in a straight line when the position relationship acquisition unit has determined the position relationship, if the distance between each of the starting point and the ending point and the reference axis is less than or equal to a second threshold; and determines the target rotational speed of each of the electric motors for moving the automated guided vehicle forward while aligning the vehicle body's central axis with the guide line when the distance between at least one of the starting point and the ending point and the reference axis is greater than the second threshold, the automated guided vehicle according to any one of claims 1 to 6.

8. The automated guided vehicle according to any one of claims 1 to 7, further comprising: a stop marker detector for detecting a stop marker provided near the guide wire; and an operation marker detector for detecting an operation marker provided near the stop marker and reading operation information of the automated guided vehicle from the detected operation marker, wherein the target value determination unit determines the target rotational speed of each of the electric motors for stopping the automated guided vehicle when the stop marker detector detects the stop marker, and after the automated guided vehicle has stopped, determines the target rotational speed of each of the electric motors according to the operation information obtained from the operation marker detector.

9. The automated guided vehicle according to claim 8, wherein, when the stop marker detector has detected the stop marker and the operation marker detector has detected the operation marker but has not read the operation information from the operation marker, the target value determination unit determines the target rotational speed of each of the electric motors to move the automated guided vehicle backward at a lower speed than when moving forward, according to the position relationship obtained by the position relationship acquisition unit.

10. The automated guided vehicle according to claim 8 or 9, wherein when the stop marker detector detects the stop marker but the operation marker detector does not detect the operation marker, the target value determination unit determines the target rotational speed of each of the electric motors for moving the automated guided vehicle forward while aligning the vehicle's central axis with the guide line, according to the positional relationship obtained by the positional relationship acquisition unit.

11. The position relationship acquisition unit determines the length of the guide line in the extension direction in the image data as the position relationship; the target value determination unit determines the target rotation speed of each of the electric motors for advancing the automated guided vehicle when the operation information acquired from the operation marker detector is a left turn or a right turn; and determines the target rotation speed of each of the electric motors according to the operation information after the length of the guide line in the extension direction falls below a third threshold; the automated guided vehicle according to any one of claims 8 to 10.

12. The unmanned transport vehicle according to any one of claims 1 to 11, further comprising a guide line detector that detects the guide line in the image data generated by a camera that photographs the road surface located below the vehicle body, and if the guide line is detected, outputs the image data to which a guide center line, which is a line passing through the center of the guide line in the width direction and extending in the direction of extension of the guide line, is added, and if the guide line is not detected, outputs the image data to the image data, wherein the position relationship acquisition unit determines the position relationship between the vehicle body and the guide center line based on the image data output by the guide line detector.

13. The guide line detector is mounted on the vehicle body at a position where the vertically extending center line of the camera lens is included in a plane that includes the vehicle body's central axis and an axis extending vertically when the automated guided vehicle is positioned horizontally, according to claim 12.

14. The control device further comprises a road surface condition estimation unit that estimates a road surface condition including at least one of the road surface gradient and the road surface irregularities from the image data, and determines a correction amount for correcting the rotation speed of the electric motor based on the estimated road surface condition, and the target value determination unit determines, when the position relationship is determined by the position relationship acquisition unit, a target rotation speed which is a target value for the rotation speed of each of the electric motors for moving the vehicle body central axis along the guide line while the automated guide vehicle moves forward, according to the determined position relationship and the correction amount, and when the position relationship is not determined by the position relationship acquisition unit, the target rotation speed of each of the electric motors for rotating the automated guide vehicle toward the guide line based on the position relationship and the correction amount most recently determined by the position relationship acquisition unit, according to any one of claims 1 to 13.

15. The automated guided vehicle according to claim 14, wherein the road surface condition estimation unit estimates the road surface condition by performing shading analysis on the image data, determines the reliability of the road surface condition estimation process based on the quality of the image data and the accuracy of shading detection of the road surface by the shading analysis, and adjusts the correction amount according to the reliability.

16. An automated guided vehicle (AGV) that travels along a guide line provided on the road surface, comprising: a vehicle body; a pair of drive wheels mounted on the vehicle body in the width direction of the vehicle body; driven wheels mounted on the vehicle body at a position offset from the guide line and in contact with the road surface when the vehicle body's central axis, which is the central axis of the vehicle body extending in the direction of travel, is on the guide line; and a pair of electric motors that rotate each of the drive wheels by being driven by supplied power, the control device for controlling the electric motors of the AGV, comprising: a position relationship acquisition unit that determines the position relationship between the vehicle body and the guide line based on image data indicating the state of the road surface located below the vehicle body; A control device comprising: when the position relationship is determined by the position relationship acquisition unit, a target rotational speed is determined, which is the target value of the rotational speed of each of the electric motors for moving the automated guided vehicle forward and aligning the vehicle's central axis with the guide line, according to the determined position relationship; when the position relationship is not determined by the position relationship acquisition unit, a target value determination unit determines the target rotational speed of each of the electric motors for rotating the automated guided vehicle toward the guide line based on the position relationship most recently determined by the position relationship acquisition unit; and a drive unit operates each of the electric motors according to the target rotational speed determined by the target value determination unit.

17. An automated guided vehicle (AGV) that travels along a guide line provided on a road surface, comprising: a vehicle body; a pair of drive wheels mounted on the vehicle body in the width direction of the vehicle body; driven wheels mounted on the vehicle body at a position offset from the guide line and in contact with the road surface when the vehicle body's central axis, which is the central axis of the vehicle body extending in the direction of travel, is on the guide line; and a pair of electric motors that are driven by supplied power to rotate each of the drive wheels, wherein the positional relationship between the vehicle body and the guide line is determined based on image data indicating the condition of the road surface located below the vehicle body, A control method comprising: when the aforementioned positional relationship is determined, determining the target rotational speed of each of the electric motors for moving the automated guided vehicle forward while aligning the vehicle's central axis with the guide line, according to the determined positional relationship; when the aforementioned positional relationship cannot be determined, determining the target rotational speed of each of the electric motors for rotating the automated guided vehicle toward the guide line, based on the most recently determined positional relationship; and operating each of the electric motors according to the determined target rotational speed.

18. An automated guided vehicle (AGV) that travels along a guide line provided on the road surface, comprising: a vehicle body; a pair of drive wheels mounted on the vehicle body in the width direction of the vehicle body; driven wheels mounted on the vehicle body at a position offset from the guide line and in contact with the road surface when the vehicle body's central axis, which is the central axis of the vehicle body extending in the direction of travel, is on the guide line; and a pair of electric motors that rotate each of the drive wheels by being driven by supplied power; a computer for controlling the electric motors of the AGV, comprising: a position relationship acquisition unit that determines the position relationship between the vehicle body and the guide line based on image data showing the condition of the road surface located below the vehicle body; A program to function as follows: when the position relationship is determined by the position relationship acquisition unit, a target rotational speed is determined, which is the target value of the rotational speed of each of the electric motors for moving the automated guided vehicle forward and aligning the vehicle's central axis with the guide line, according to the determined position relationship; when the position relationship is not determined by the position relationship acquisition unit, a target value determination unit that determines the target rotational speed of each of the electric motors for rotating the automated guided vehicle toward the guide line based on the position relationship most recently determined by the position relationship acquisition unit; and a drive unit that operates each of the electric motors according to the target rotational speed determined by the target value determination unit.

Images