Automated guided vehicle control method and automated guiding system

Abstract

In the present invention, an automated guided vehicle has a plurality of drive wheels that can be rotationally driven independently of each other so as to be movable in all directions, and is guided while being connected with a cart. This automated guided vehicle control method involves acquiring the weight of a cart with which an automated guided vehicle is connected, and controls, on the basis of the acquired weight of the cart, the automated guided vehicle so as to guide the cart to a guiding destination while restricting the movement of the automated guided vehicle connected with the cart in a specific direction.

Description

Control method for automated guided vehicle and automated guided vehicle system

[0001] This specification discloses a method for controlling an automated guided vehicle and an automated guided vehicle system.

[0002] Conventionally, an automatic driving system has been proposed in which driving parameters are set according to the weight of the load to be transported by the AGV (automated guided vehicle), and the AGV is controlled to travel based on the set driving parameters (see, for example, Patent Document 1). The driving parameters include a target traveling speed, an acceleration rate until the target speed is reached, a deceleration rate until the target speed is reached, etc., and different sets of parameters are set corresponding to each weight category.

[0003] JP 2022-45454 A

[0004] In some automated guided vehicles, the slipperiness of the drive wheels may differ depending on the direction of travel, depending on the type of drive wheels, such as Mecanum wheels or omni wheels. In this case, as the weight of the carriage connected to the automated guided vehicle increases, slippage occurs in the drive wheels when the carriage moves in a specific direction, making it difficult to transport the carriage.

[0005] A primary object of the present disclosure is to efficiently transport a cart to its destination while suppressing slippage of drive wheels during transport of the cart.

[0006] The present disclosure has adopted the following means to achieve the above-mentioned main object.

[0007] The control method for an automated guided vehicle disclosed herein is a control method for an automated guided vehicle that has multiple drive wheels that can be rotated independently so as to be movable in all directions, and that is connected to a cart for transport, and the method involves obtaining the weight of the cart to which the automated guided vehicle is connected, and controlling the automated guided vehicle to transport the cart to a destination while restricting the movement of the automated guided vehicle to the connected cart in a specific direction based on the obtained weight of the cart.

[0008] In the method for controlling an automated guided vehicle disclosed herein, the automated guided vehicle is controlled to transport the cart to its destination while restricting movement in a specific direction based on the weight of the cart connected to the automated guided vehicle. By setting the specific direction as a direction in which the drive wheels are likely to slip, it is possible to efficiently transport the cart to its destination while suppressing slippage of the drive wheels during transport.

[0009] The automatic transport system disclosed herein is an automatic transport system that includes an automatic transport vehicle that has multiple drive wheels that can each be rotated independently so that it can move in all directions and that is connected to a cart for transport, and that includes an acquisition unit that acquires the weight of the cart to which the automatic transport vehicle is connected, and a control unit that controls the automatic transport vehicle to transport the cart to a destination while restricting the movement of the automatic transport vehicle to the connected cart in a specific direction based on the acquired weight of the cart.

[0010] The automatic transport system of the present disclosure can achieve the same effects as the automatic transport vehicle control method of the present disclosure.

[0011] 1 is a perspective view showing an appearance of a state in which a plurality of basket carts arranged in a cart storage area are transported by an automated guided vehicle. FIG. 1 is a perspective view showing an appearance of an automated guided vehicle and a basket cart. FIG. 2 is a perspective view showing an appearance of an automated guided vehicle. FIG. 3 is a schematic configuration diagram of a drive system of an automated guided vehicle. FIG. 4 is a side view of an automated guided vehicle. FIG. 5 is a side view of an automated guided vehicle. FIG. 6 is an explanatory diagram showing a state in which an automated guided vehicle has slipped under a basket cart. FIG. 7 is an explanatory diagram showing a state in which an automated guided vehicle is coupled to a basket cart. FIG. 8 is a block diagram of an automated guided system including an automated guided vehicle and a management device. FIG. 9 is an explanatory diagram showing an example of destination information. FIG. 10 is an explanatory diagram showing an example of obstacle information. FIG. 11 is a flowchart showing an example of transport control processing. FIG. 12 is a flowchart showing an example of travel control processing. FIG. 13 is a flowchart showing an example of travel condition setting processing. FIG. 14 is an explanatory diagram showing how an automated guided vehicle moves when lateral movement is permitted and the destination is in a lateral direction as seen from the automated guided vehicle. FIG. 15 is an explanatory diagram showing how an automated guided vehicle moves when lateral movement is prohibited and the destination is in a lateral direction as seen from the automated guided vehicle. 10 is a flowchart illustrating a travel control process according to another embodiment of the present invention;

[0012] Next, embodiments of the present disclosure will be described with reference to the drawings.

[0013] FIG. 1 is an external perspective view showing a state in which a plurality of basket carts 100 arranged in a cart storage area L are transported by an automated guided vehicle 10. FIG. 2 is an external perspective view of the basket cart 100 and the automated guided vehicle 10. FIG. 3 is an external perspective view of the automated guided vehicle 10. FIG. 4 is a schematic configuration diagram of the drive system of the automated guided vehicle 10. FIGS. 5 and 6 are side views of the automated guided vehicle 10. FIG. 7 is an explanatory diagram showing a state in which the automated guided vehicle 10 has slipped under the basket cart 100. FIG. 8 is an explanatory diagram showing a state in which the automated guided vehicle 10 is coupled to the basket cart 100. FIG. 9 is a block diagram of an automatic guided system 1 including the automated guided vehicle 10 and a management device 60.

[0014] 1 , an automated guided vehicle system 1 of this embodiment is used in a logistics center, warehouse, store, or the like having a plurality of shelves S, and includes one or a plurality of automated guided vehicles 10 and a management device 60 (see FIG. 9 ) that manages the operation of the automated guided vehicles 10. The automated guided vehicles 10 are autonomously traveling transport robots (AMR: Autonomous Mobile Robot) that are coupled to a basket cart 100 and transport the automated guided vehicles 10 to a designated shelf S.

[0015] As shown in FIG. 2 , the basket cart 100 includes a basket-shaped platform 101 having a rectangular, mesh-like planar shape on which cargo C can be loaded, and a plurality of (four) casters 110 rotatably attached to the four corners of the underside of the platform 101. A marker M, such as an AR marker, a two-dimensional code, or a barcode, is provided on the platform 101 of the basket cart 100 (in the present embodiment, the center of the outer edge front end surface of the platform 101) for identifying the basket cart 100. By reading the marker M, the automated guided vehicle 10 recognizes the basket cart 100 to be transported (transport target vehicle) and the type (baggage ID) of the cargo C loaded on the platform 101. The marker M may be attached to the cargo C loaded on the platform 101. The identification information for identifying the basket cart 100 and the cargo C is not limited to the marker M. For example, the identification information may be a unique ID that identifies the cart 100. Furthermore, the identification information may be identification information (such as letters or a picture) marked on the outer box of the package C.

[0016] As shown in Fig. 3, the automated guided vehicle 10 of this embodiment has a low, flat, rectangular parallelepiped appearance. The automated guided vehicle 10 slides under a cart 100 and travels coupled with the cart 100 to transport the cart 100. As shown in Figs. 3 and 4, the automated guided vehicle 10 includes a vehicle body 11, a plurality of (e.g., four) wheels 21 rotatably attached to the bottom surface of the vehicle body 11, and a plurality of (e.g., four) drive motors 22 that rotate and drive the corresponding wheels 21.

[0017] In this embodiment, as shown in Fig. 4, each wheel 12 is configured as a Mecanum wheel having a wheel body 12h connected to an axle and a plurality of rollers 12r attached to the outer periphery of the wheel body 12h so as to be rotatable around an axis inclined at 45 degrees relative to the axle. The automated guided vehicle 10 is capable of omnidirectional movement without a steering mechanism by independently driving the rotation direction and rotation speed of each of the corresponding wheels 12 using four drive motors 22. For example, the automated guided vehicle 10 moves forward by rotating all four wheels 12 (front right wheel, front left wheel, rear right wheel, and rear left wheel) 12 forward at the same rotational speed, and moves backward by rotating all four wheels 12 backward at the same rotational speed. The automated guided vehicle 10 moves laterally to the right by rotating the left front wheel and the right rear wheel of the four wheels 12 forward and rotating the right front wheel and the left rear wheel in the reverse direction, and moves laterally to the left by rotating the right front wheel and the left rear wheel of the four wheels 12 forward and rotating the left front wheel and the right rear wheel in the reverse direction. Furthermore, the automated guided vehicle 10 moves diagonally forward to the right by rotating the left front wheel and the right rear wheel of the four wheels 12 forward, and moves diagonally forward to the left by rotating the right front wheel and the left rear wheel of the four wheels 12 forward. The automated guided vehicle 10 can rotate clockwise around the center of the vehicle body 11 as a pivot axis by rotating the left front wheel and the left rear wheel of the four wheels 12 forward and rotating the right front wheel and the right rear wheel backward. Alternatively, the automated guided vehicle 10 can rotate counterclockwise around the center of the vehicle body 11 as a pivot axis by rotating the right front wheel and the right rear wheel of the four wheels 12 forward and rotating the left front wheel and the left rear wheel backward. The automated guided vehicle 10 can also move diagonally backward to the right or left, or rotate around another position on the vehicle body 11 as a pivot axis (such as the right front wheel, left front wheel, right rear wheel, left rear wheel, the center of the left and right front wheels, or the center of the left and right rear wheels). The wheels 12 are not limited to Mecanum wheels, but may be omniwheels having multiple rollers rotatable around an axis that intersects with the axis of rotation of the wheel body. By arranging three or four omni-wheels on the circumference of the body part 11 and driving each wheel independently by a motor, the body part 11 can be moved in multiple directions (forward movement, backward movement, parallel movement, diagonal movement, turning, etc.).

[0018] 3, 5, and 6, the automated guided vehicle 10 includes a connecting unit 30 that is provided on the upper surface of the vehicle body 11 and can be connected to the cart 100 when the vehicle body 11 is positioned below the cart 100. The connecting unit 30 includes a flat lift plate 31, a plurality of connecting pins 32, 33, and 34 that extend upward and are provided retractably relative to the lift plate 31, and an elevator 35 that raises and lowers the lift plate 31 by driving a motor (not shown). The lift plate 31 covers the upper surface of the vehicle body 11 and has a width that is approximately the same as the width of the vehicle body 11 and a front-to-rear width that is slightly shorter than the front-to-rear width of the vehicle body 11. The connecting pin 32 is provided at the front of the lift plate 31, the connecting pin 33 is provided at the rear of the lift plate 31, and the connecting pin 34 is provided at an intermediate portion between the front and rear of the lift plate 31. 7 and 8 , when the vehicle body 11 of the connecting unit 30 is submerged under the cart 100, the lifting device 35 raises the lifting plate 31, and at least one of the connecting pins 32, 33, 34 that rise together with the lifting plate 31 engages with the back side of the loading platform 101 of the cart 100. This connects the cart 100 to the automated guided vehicle 10. Furthermore, when the lifting device 35 lowers the lifting plate 31 of the connecting unit 30, the connecting pins 32, 33, 34 are released from engagement with the loading platform 101 of the cart 100. This disconnects the automated guided vehicle 10 from the cart 100.

[0019] As shown in Figures 3, 5, and 6, contact detection sensors 36 (spring sensors) are provided on both the left and right sides of the lift plate 31 to detect when the connecting portion 30 (connecting pins 32, 33, 34) comes into contact with (connects to) the loading platform 101 of the cart truck 100. The contact detection sensors 36 have a contact plate that is biased upward by a spring to a height substantially equal to that of the connecting pins 32, 33, 34 extended relative to the lift plate 31 and can move up and down. When the connecting pins 32, 33, 34 engage with the loading platform 101 of the cart truck 100, the contact plate of the contact detection sensor 36 comes into contact with the loading platform 101, and the spring is compressed as it descends relative to the lift plate 31. The contact detection sensor 36 detects when the contact plate has descended relative to the lift plate 31, thereby detecting when the connecting portion 30 has come into contact with (connects to) the loading platform 101 of the cart truck 100.

[0020] As shown in FIG. 9 , the automated guided vehicle 10 further includes a control unit 40 that controls the entire system, a memory unit 41 that stores various information including map information 41a, a communication unit 42 that communicates (wirelessly communicates) with a management device 60, a camera unit 51 as an imaging device, sensors 52 and 53, and a light-emitting unit 54 that illuminates the area ahead of the vehicle body 11. The camera unit 51 is installed on the front of the vehicle body 11 to recognize the area ahead of the vehicle body 11. The sensors 52 and 53 are installed on the front and rear of the vehicle body 11, respectively, to detect surrounding objects. The sensors 52 and 53 detect surrounding objects and the distances to the objects. In this embodiment, the sensors 52 and 53 are LiDAR (Light Detection and Ranging) sensors that scan the surroundings with laser light, receive each reflected light, and measure the time it takes for the reflected light to be received, thereby measuring distance data for each scan angle and obtaining two-dimensional point cloud data of the surroundings. The light emitting unit 54 is installed on the front of the vehicle body 11 and illuminates the area ahead, making it easier for the camera unit 51 to recognize surrounding objects in dark places.

[0021] The control unit 40 is configured as a microprocessor centered on a CPU, and in addition to the CPU, includes a ROM for storing processing programs such as the transport control processing described below, a RAM for temporarily storing data, a timer, etc. As shown in Fig. 9, the control unit 40 receives inputs such as detection signals from wheel speed sensors (not shown) that detect the rotational speed of each wheel 12, image signals from a camera unit 51, detection signals from sensor units 52 and 53, and detection signals from the contact detection sensor 36. The control unit 40 outputs control signals to the drive motor 22, control signals to the lifting device 35, etc.

[0022] When the unmanned guided vehicle 10 is traveling, the control unit 40 calculates the traveling speed of the unmanned guided vehicle 10 based on the rotational speed of each wheel 12, sets a torque command for each drive motor 22 by feedback control so that the calculated traveling speed becomes the target speed, and drives and controls each drive motor 22 so that a torque corresponding to the set torque command is output.

[0023] In addition, when connecting the cart 100, the control unit 40 controls the drive of the motor of the lifting device 35 using feedback control so that the motor rotates at a constant rotational speed until the contact detection sensor 36 detects that the cart 100 has been connected.

[0024] As shown in Fig. 9, the management device 60 includes a processing unit 61, a storage unit 62, and a communication unit 63 for communicating (wirelessly communicating) with each automated guided vehicle 10. An input unit 65 such as a mouse and a keyboard, and a display unit 66 such as a liquid crystal display, are also connected to the management device 60. The processing unit 61 is configured as a microprocessor centered around a CPU, and includes, in addition to the CPU, a ROM for storing processing programs and a RAM for temporarily storing data. The storage unit 62 is a storage device such as an HDD or SSD, and stores various types of information such as destination information 62b (see Fig. 10) and obstacle information 62c (see Fig. 11) in addition to map information 62a.

[0025] As shown in Figure 10, the destination information 62b is information that corresponds the type of luggage C (luggage ID), the coordinate value of the destination of luggage C (basket cart 100), and the orientation of the basket cart 100 at the destination, and is registered in advance in the memory unit 62.

[0026] The obstacle information 62c is information relating to obstacles (such as transported carts 100) placed on the map. As shown in Fig. 11 , the obstacle information 62c associates an obstacle ID for identifying the obstacle, a registration time which is the date and time when the obstacle was registered, the position (x, y) of the obstacle on the map, and the orientation of the obstacle (cart 100). The obstacle is set at the position of the destination when the automated guided vehicle 10 transports the cart 100 to the destination by the transport control process.

[0027] Next, the operation of the automated guided vehicle 1 of this embodiment configured as described above will be described. In particular, as shown in Fig. 1, the operation of the automated guided vehicle 10 when transporting a plurality of basket carts 100 arranged in a cart storage area L one by one to their respective destinations will be described. Fig. 12 is a flowchart showing an example of transport control processing executed by the control unit 40 of the automated guided vehicle 10. This processing is executed when an instruction to transport a basket cart 100 (baggage) is received from the management device 60.

[0028] When the transport control process is executed, the control unit 40 first controls the drive motor 22 to move the cart to the cart storage area L (S100). Next, the control unit 40 searches for nearby basket carts 100 (S102). The search for the basket cart 100 is performed, for example, by capturing an image of the area around the vehicle body 11 with the camera unit 51 and processing the captured image to determine whether or not the marker M attached to the cart 100 has been recognized. If the control unit 40 determines that it has failed to recognize the marker M, it determines that there is no basket cart 100 to be transported at the cart storage area L (NO in S104), and ends the transport control process.

[0029] On the other hand, if the control unit 40 determines that the recognition of the marker M was successful, it determines that there is a basket cart 100 to be transported at the cart storage area L (YES in S104), and, with the basket cart 100 as the transport target cart, acquires the coordinate values ​​of the destination to which the transport target cart should be transported and the orientation of the transport target cart at the destination based on the type of luggage C identified by the marker ID of the recognized marker M (S106). The processing of S106 is performed, for example, by transmitting the marker ID recognized by the control unit 40 to the management device 60, identifying the type of luggage C from the received marker ID, and deriving the corresponding coordinate values ​​of the destination and the orientation of the transport target cart from the destination information 62b based on the type of luggage C, and transmitting them to the control unit 40 of the automatic guided vehicle 10. Note that the control unit 40 may also identify the type of luggage C from the marker ID and transmit the identified type of luggage C to the management device 60. In addition, the control unit 40 may store destination information 62b in the memory unit 41, identify the type of luggage C from the marker ID, and obtain the coordinate values ​​of the corresponding destination and the orientation of the cart to be transported from the destination information 62b based on the identified type of luggage C.

[0030] Next, the control unit 40 acquires obstacle information 62c from the management device 60 (S108). The obstacle information 62c may be stored in the storage unit 41 of the automated guided vehicle 10. The control unit 40 then sets the coordinate values ​​of the destination of the transport target vehicle acquired in S106 as the destination (S112), and sets a transport route to the destination based on the map information 41a stored in the storage unit 41 and the obstacle information 62c acquired in S108 (S112). The transport route is specifically set as follows. That is, the control unit 40 recognizes the shape of the surrounding area based on point cloud data measured by the sensor units 52 and 53 (LiDAR), and recognizes the current location (self-position) of the vehicle by comparing (collating) the recognized shape of the surrounding area with the map information stored in the storage unit 41. The control unit 40 then performs a route search based on the recognized current location, the set destination, and the map information 41a. Next, the control unit 40 determines whether the automated guided vehicle 10 transporting the cart 100 can travel along each of the searched routes to the destination. In this embodiment, the obstacle information 62c includes the position of the transported cart 100 (obstacle) on the map and the orientation of the cart 100, and the map information 41a includes road width information. Because the size of the cart 100 is known, the control unit 40 can determine whether the searched route is passable based on the size of the cart 100 coupled to the automated guided vehicle 10, the map information 41a, and the obstacle information 62c. The control unit 40 then sets the route with the shortest required time or travel distance as the transport route among the passable routes. This allows the cart to be transported to the destination in a short time without interfering with the transported cart 100. In addition, the control unit 40 of the unmanned guided vehicle 10 may transmit the current location of the vehicle to the management device 60, and the management device 60 may set a transport route based on the map information 62a and obstacle information 62c and transmit the route to the control unit 40 of the unmanned guided vehicle 10.

[0031] After setting the destination and transport route of the transport target cart, the control unit 40 couples to the transport target cart (S114). This process is performed as follows. That is, the control unit 40 first recognizes the two casters 110 of the transport target cart using the sensor unit 52. Next, the control unit 40 controls the drive motor 22 so that the control unit 40 moves between the two recognized casters 110 and under the transport target cart. Then, the control unit 40 raises the coupling pins 32, 33, and 34 using the lifting device 35 so that they engage with the loading platform 101 of the transport target cart, thereby coupling to the transport target cart.

[0032] Once coupled to the transport target vehicle, the control unit 40 starts transporting the transport target vehicle according to the set transport route (S116). Next, the control unit 40 executes travel control (S118), acquires its own position (S120), and determines whether it has arrived at the destination (S122) while executing travel control. Travel control will be described later. If the control unit 40 determines that it has not arrived at the destination, it returns to S118. If it determines that it has arrived at the destination, it stops travel (S124) and releases the coupling with the transport target vehicle (S126). The control unit 40 then sets an obstacle at the location (destination) to which the transport target vehicle has been transported (S128) and returns to S100. The obstacle is set by the control unit 40 transmitting the coordinate values ​​and orientation of the transport target vehicle to the management device 60, and the management device 60 assigns an obstacle ID and a registration time to the coordinate values ​​and orientation of the obstacle (transport target vehicle) received, and registers them in the obstacle information 62c. As a result, the next time the transport control process is executed, the obstacle information 62c will have been added, and if there is a transported cart 100 between the current location and the destination, the transport route will be set to avoid it.

[0033] In this way, the control unit 40 repeats the process of connecting the basket carts 100 one by one and transporting them to their respective destinations until it determines in S104 that there are no basket carts 100 to be transported to the cart storage area L.

[0034] Next, the driving control executed in S118 will be described. Fig. 13 is a flowchart showing an example of the driving control process executed by the control unit 40. In the driving control process, the control unit 40 first acquires driving conditions (S200). In this embodiment, the driving conditions include the maximum vehicle speed Vmax of the automatic guided vehicle 10 and the direction in which the automatic guided vehicle 10 can travel. The driving conditions are acquired by acquiring the driving conditions set by the driving condition setting process shown in Fig. 14.

[0035] In the travel condition setting process, the control unit 40 first acquires the weight M of the target cart (S300). The weight M of the target cart can be estimated based on the torque value of the motor of the lifting device 35 when the motor is driven to raise the connecting pins 32, 33, and 34 to couple with the target cart, or based on the torque value of the drive motor 22 when the drive motor 22 is driven to drive the automated guided vehicle 10 coupled with the target cart and the automated guided vehicle 10 starts traveling. Alternatively, the weight M of the target cart may be estimated based on the detection value of a load cell mounted on the lifting device 35 when the connecting pins 32, 33, and 34 are raised to couple with the target cart. Next, the control unit 40 determines whether the acquired weight M of the target cart is less than a threshold value Mref (S302). When the control unit 40 determines that the weight M of the transport target vehicle is less than the threshold value Mref, it sets the maximum speed Vmax to the high speed VH (S304), permits movement in all directions (S306), and terminates the travel condition setting process. On the other hand, when the control unit 40 determines that the weight M of the transport target vehicle is equal to or greater than the threshold value Mref, it sets the maximum speed Vmax to the low speed VL that is lower than the high speed VH (S308), prohibits lateral movement (S310), and terminates the travel condition setting process.

[0036] Returning to the travel control process, once the control unit 40 has acquired the travel conditions in this manner, it acquires its own position (S202) and determines whether the automated guided vehicle 10 is located near the destination (S204). This process is performed by calculating the distance between the coordinates of the self-position and the coordinates of the destination based on the coordinates of the self-position and determining whether the calculated distance is within a predetermined distance range. Note that the acquisition of the self-position was described above. If the control unit 40 determines that the automated guided vehicle 10 is not located near the destination, it controls the drive motor 22 to travel on the transport route at a maximum vehicle speed Vmax or less (S206), and ends the travel control process.

[0037] On the other hand, if the control unit 40 determines that the automated guided vehicle 10 is located near the destination, it determines the direction of the destination relative to its own position acquired in S202 (S208). If the control unit 40 determines that the direction of the destination is in the forward / backward direction, it controls the drive motor 22 to travel toward the destination by forward / backward movement (S210), and ends the travel control process. If the control unit 40 determines that the direction of the destination is in a diagonal direction, it controls the drive motor 22 to travel toward the destination by diagonal movement (S212), and ends the travel control process.

[0038] If the control unit 40 determines that the direction of the destination is lateral, it further determines whether lateral movement is prohibited (S214). If the control unit 40 determines that lateral movement is not prohibited, it controls the drive motor 22 to travel toward the destination by lateral movement (S216), as shown in FIG. 15, and terminates the travel control process. On the other hand, if the control unit 40 determines that lateral movement is prohibited, it controls the drive motor 22 to travel toward the destination by a combination of forward / backward movement and diagonal movement, which are not prohibited (S218), and terminates the travel control process. For example, if the destination is located to the right, the control unit 40 may control the drive motor 22 to travel forward (see FIG. 16A), and then control the drive motor 22 to travel diagonally backward to the right (see FIG. 16B). Alternatively, the control unit 40 may move diagonally forward to the right and then reverse, or may move diagonally backward to the right and then forward, or may move backward and then diagonally forward to the right. Furthermore, if the destination is located to the left, the control unit 40 may move the vehicle forward and then diagonally rearward to the left, or may move the vehicle diagonally forward to the left and then diagonally backward, or may move the vehicle diagonally rearward to the left and then diagonally forward, or may move the vehicle diagonally forward to the left and then diagonally forward. As described above, lateral movement is permitted if the weight M of the vehicle to be transported is less than the threshold value Mref, and is prohibited if the weight M of the vehicle to be transported is equal to or greater than the threshold value Mref. Lateral movement is likely to cause slippage of the wheels 12 because the front and rear wheels 12 on the same side rotate in opposite directions. However, if the vehicle to be transported is lightweight, the load on the wheels 12 is reduced, and the automated guided vehicle 10 can move laterally without causing slippage of the wheels 12. Therefore, if the weight M of the vehicle to be transported is less than the threshold value Mref, permitting lateral movement allows the vehicle to be transported laterally to its destination in a short time. On the other hand, when the weight M of the transport target cart is equal to or greater than the threshold value Mref, lateral movement is prohibited, thereby suppressing slippage of the wheels 12 and enabling the transport target cart to be transported stably to its destination. In addition, when the weight M of the transport target cart is less than the threshold value Mref, the maximum vehicle speed Vmax is set to the high speed VH, thereby further shortening the time required to transport the transport target cart.On the other hand, when the weight M of the transport target cart is equal to or greater than the threshold value Mref, the maximum vehicle speed Vmax can be set to the low speed VL, thereby making it possible to make the transport target cart more stable during transportation.

[0039] Here, the correspondence between the main elements of the embodiment and the main elements of the present disclosure described in the claims will be described. That is, the cart 100 of the present embodiment is an example of a cart of the present disclosure, the automatic guided vehicle 10 is an example of an automatic guided vehicle, the control unit 40 that executes S300 of the driving condition setting process is an example of an acquisition unit, and the control unit 40 that executes the transport control process, S302 to S310 of the driving condition setting process, and the driving control process is an example of a control unit.

[0040] It goes without saying that the present disclosure is not limited to the above-described embodiments, and can be embodied in various forms as long as they fall within the technical scope of the present disclosure.

[0041] For example, in the above-described embodiment, when lateral movement is prohibited in the driving control process, the control unit 40 moves the vehicle by combining forward / backward movement and diagonal movement to a destination located laterally. However, the control unit 40 may also control the drive motor 22 to move to a destination located laterally by combining forward / backward movement and turning, or by combining diagonal movement and turning. For example, if the destination is located to the right, the control unit 40 may control the drive motor 22 to turn 90 degrees clockwise (see FIG. 17A) and then move forward (see FIG. 17B), or may turn 45 degrees clockwise and then move diagonally forward to the right. Furthermore, if the destination is located to the left, the control unit 40 may turn 90 degrees counterclockwise and then move forward, or may turn 45 degrees counterclockwise and then move diagonally forward to the left. FIG. 18 shows a driving control process according to another embodiment in this case. The driving control process in FIG. 18 is the same as the driving control process in FIG. 13 except that the process of S218B is executed instead of the process of S218.

[0042] In the embodiment described above, the automated guided vehicle 10 engages the connecting pin 34 of the connecting portion 30 with the loading platform portion 101 of the basket cart 100 to tow the basket cart 100. However, the automated guided vehicle 10 may also be configured to lift the basket cart 100 with the connecting portion 30 and transport it.

[0043] As described above, the control method for an automated guided vehicle disclosed herein controls the automated guided vehicle so that the connected cart is transported to the destination while restricting movement in a specific direction based on the weight of the connected cart. By setting the specific direction as a direction in which the drive wheels are likely to slip, it is possible to efficiently transport the cart to the destination while suppressing slippage of the drive wheels during transport.

[0044] In the control method for an automated guided vehicle according to the present disclosure, the plurality of drive wheels may be Mecanum wheels or omni-wheels, and the specific direction may be a lateral direction. In particular, with Mecanum wheels, lateral movement is prone to slippage of the drive wheels because the front and rear drive wheels on the same side rotate in opposite directions. However, if the carriage is lightweight, the load on the drive wheels is reduced, allowing the automated guided vehicle to move laterally without slippage of the drive wheels.

[0045] Furthermore, in the method for controlling an automated guided vehicle disclosed herein, if the weight of the carriage is less than a predetermined value, the automated guided vehicle connected to the carriage may be permitted to move in the specific direction, and if the weight of the carriage is equal to or greater than the predetermined value, the automated guided vehicle connected to the carriage may be prohibited from moving in the specific direction. This allows the carriage to be efficiently transported to its destination while suppressing slippage of its drive wheels during transport through simple processing. In this case, when the destination is located in the specific direction relative to its current position, if the weight of the carriage is less than the predetermined value, the automated guided vehicle may be controlled to transport the carriage to the destination by moving in the specific direction. If the weight of the carriage is equal to or greater than the predetermined value, the automated guided vehicle may be controlled to transport the carriage to the destination by a combination of movements in at least two directions different from the specific direction or a combination of movement in a direction different from the specific direction and a turn. If the weight of the carriage is less than the predetermined value, the carriage can be moved directly to the destination located in the specific direction, thereby reducing the time required to transport the carriage. Furthermore, even if the weight of the cart is equal to or greater than a predetermined value, the cart can be transported to the destination more reliably.

[0046] Furthermore, in the control method for an automated guided vehicle disclosed herein, the maximum speed of the automated guided vehicle when transporting the cart may be further limited based on the weight of the cart. In this case, when the weight of the cart is equal to or greater than a predetermined value, the maximum speed may be set lower than when the weight of the cart is less than the predetermined value. When the weight of the cart is less than the predetermined value, the time required to transport the cart can be further reduced. On the other hand, when the weight M of the cart is equal to or greater than a predetermined value, the cart can be made more stable during transportation.

[0047] Although the present disclosure has been described as a control method for an automated guided vehicle, it may also be in the form of an automated guided vehicle system.

[0048] This specification also discloses the technical idea of ​​changing the original claim 5 of the application from "a method for controlling an unmanned guided vehicle according to claim 1 or 2" to "a method for controlling an unmanned guided vehicle according to any one of claims 1 to 4."

[0049] The present disclosure can be used in the manufacturing industry of automatic guided vehicles and automatic guided systems.

[0050] 1 Automatic transport system, 10 Automatic transport vehicle, 11 Vehicle body, 21 Wheels, 22 Drive motor, 30 Connection part, 31 Lifting plate, 32, 33, 34 Connection pin, 35 Lifting device, 36 Contact detection sensor, 40 Control part, 41 Memory part, 41a Map information, 42 Communication part, 51 Camera part, 52, 53 Sensor part, 54 Light emitting part, 60 Management device, 61 Processing part, 62 Memory part, 62a Map information, 62b Transport destination information, 62c Obstacle information, 63 Communication part, 65 Input part, 66 Display part, 100 Basket cart, 101 Loading platform part, 110 Caster, C Baggage, L Cart storage area, M Marker, S Shelf.

Claims

A method for controlling an automated guided vehicle that has a plurality of drive wheels that can be rotated independently and move in all directions, and that is connected to a carriage for transport, comprising: Acquire the weight of the carriage to which the automated guided vehicle is connected; controlling the automated guided vehicle to transport the cart to a destination while restricting movement of the automated guided vehicle connected to the cart in a specific direction based on the acquired weight of the cart; A method for controlling an automated guided vehicle.

2. The method for controlling an automated guided vehicle according to claim 1, the plurality of drive wheels are Mecanum wheels or Omni wheels; The specific direction is a lateral direction. A method for controlling an automated guided vehicle.

3. A method for controlling an automated guided vehicle according to claim 1 or 2, When the weight of the carriage is less than a predetermined value, the automatic guided vehicle connected to the carriage is permitted to move in the specific direction, and when the weight of the carriage is equal to or greater than the predetermined value, the automatic guided vehicle connected to the carriage is prohibited from moving in the specific direction. A method for controlling an automated guided vehicle.

4. The method for controlling an automated guided vehicle according to claim 3, When the destination is located in the specific direction with respect to the current position, if the weight of the carriage is less than the predetermined value, the automated guided vehicle is controlled to transport the carriage to the destination by movement in the specific direction, and if the weight of the carriage is equal to or greater than the predetermined value, the automated guided vehicle is controlled to transport the carriage to the destination by a combination of movements in at least two directions different from the specific direction or a combination of movement in a direction different from the specific direction and a turn. A method for controlling an automated guided vehicle.

3. A method for controlling an automated guided vehicle according to claim 1 or 2, and further limiting the maximum speed of the automated guided vehicle when transporting the carriage based on the weight of the carriage. A method for controlling an automated guided vehicle.

6. The method for controlling an automated guided vehicle according to claim 5, When the weight of the carriage is equal to or greater than a predetermined value, the maximum speed is set lower than when the weight is less than the predetermined value. A method for controlling an automated guided vehicle. 　 An automatic transport system including an automated guided vehicle having a plurality of drive wheels that can be rotated independently and move in all directions, and connected to a carriage for transport, an acquisition unit that acquires a weight of the carriage to which the automated guided vehicle is connected; a control unit that controls the automated guided vehicle to transport the carriage to a destination while restricting movement of the automated guided vehicle connected to the carriage in a specific direction based on the acquired weight of the carriage; and An automatic transport system comprising:

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