JP7600248B2 - Method for controlling travel of autonomous guided vehicle, autonomous guided vehicle, and transport system - Google Patents

Description

This invention relates to a method for controlling the travel of an autonomous guided vehicle, an autonomous guided vehicle, and a transport system, and in particular to a method for controlling the travel of an autonomous guided vehicle that travels autonomously by towing a cart, an autonomous guided vehicle, and a transport system for the same.

Conventionally, an autonomous guided vehicle that tows a cart and travels autonomously is known. Such a method is disclosed, for example, in Japanese Patent No. 6362418.

The above-mentioned Patent Publication No. 6362418 discloses an autonomous guided vehicle that travels autonomously by towing a cart. This autonomous guided vehicle is configured to efficiently travel around corners and other curved sections by disconnecting and reconnecting the cart when traveling around curved sections such as corners.

Patent No. 6362418

However, in the autonomous guided vehicle described in the above-mentioned Patent Publication No. 6,362,418, the cart is detached and reattached at curved sections such as corners, which takes time to move around the curved section, resulting in reduced productivity when used in manufacturing plants, etc. Therefore, it is conceivable to travel around curved sections with the autonomous guided vehicle towing the cart without detaching the cart from the autonomous guided vehicle.

However, in this case, if an autonomous guided vehicle towing a cart travels around a curved section at the same high travel speed as when the cart is not being towed, the cart may swing significantly at the curved section and tip over. Therefore, it may be possible to uniformly reduce the travel speed of the autonomous guided vehicle when towing a cart.

However, in this case, while it is possible to prevent the cart from tipping over at the bend, productivity decreases due to a decrease in the traveling speed of the autonomous guided vehicle. This poses the problem that it is difficult to increase productivity while preventing the cart from tipping over at the bend when towing the cart by the autonomous guided vehicle (the guided vehicle body).

This invention has been made to solve the problems described above, and one object of the invention is to provide a driving control method for an autonomous guided vehicle, an autonomous guided vehicle, and a transport system that can increase productivity while preventing the cart from tipping over at bending points when the cart is towed by the transport vehicle body.

A travel control method for an autonomous guided vehicle according to a first aspect of the present invention is a travel control method for an autonomous guided vehicle that travels autonomously by towing a cart, comprising the steps of acquiring a state of the cart, detecting the relative attitude of the cart with respect to the guided vehicle body based on the state of the cart, and controlling the travel speed of the guided vehicle body based on the relative attitude of the cart with respect to the guided vehicle body, wherein the guided vehicle body or the cart includes a connecting section that connects the guided vehicle body and the cart, and the guided vehicle body includes a drive section that drives the connecting section, and further comprising the step of controlling the relative attitude of the cart with respect to the guided vehicle body in a horizontal plane by driving the connecting section with the drive section when the cart is towed by the guided vehicle body, so as to counteract movement of the cart due to inertia .

In the method for controlling the travel of an autonomous transport vehicle according to the first aspect of the present invention, as described above, a step of detecting the relative attitude of the dolly with respect to the transport vehicle body based on the state of the dolly, and a step of controlling the travel speed of the transport vehicle body based on the relative attitude of the dolly with respect to the transport vehicle body are provided. In this way, when a change in the relative attitude of the dolly with respect to the transport vehicle body occurs when moving around a curved portion such as a corner, the travel speed of the transport vehicle body can be appropriately changed according to the change in the relative attitude of the dolly with respect to the transport vehicle body. As a result, unlike the case where the travel speed of the transport vehicle body is uniformly reduced when the dolly is towed by the transport vehicle body, an unnecessary reduction in the travel speed does not occur. In this way, when the dolly is towed by the transport vehicle body, it is possible to increase productivity while suppressing the dolly from tipping over at a curved portion. In addition, when an abnormality occurs in the attitude of the dolly when the dolly is towed by the transport vehicle body, the travel speed of the transport vehicle body can also be appropriately changed. This also makes it possible to suppress the dolly from tipping over when the dolly is towed by the transport vehicle body.
In addition, in the method for controlling travel of an autonomous guided vehicle according to the first aspect, the vehicle body or the cart includes a coupling part that couples the vehicle body and the cart, the vehicle body includes a drive part that drives the coupling part, and the method further includes a step of controlling the relative attitude of the cart to the vehicle body in a horizontal plane by driving the coupling part with the drive part when the vehicle body is towing the cart. With this configuration, the vehicle body can be made to travel while controlling the relative attitude of the cart to the vehicle body in the horizontal plane. As a result, the stability of travel of the vehicle body can be improved compared to a case in which the relative attitude of the cart to the vehicle body in the horizontal plane cannot be controlled.

In the method for controlling the travel of an autonomous guided vehicle according to the first aspect, preferably, the step of acquiring the state of the trolley includes a step of acquiring the state of a characteristic point of the trolley, and the step of detecting the relative attitude of the trolley with respect to the guided vehicle body includes a step of detecting the relative attitude of the trolley with respect to the guided vehicle body based on the state of the characteristic point of the trolley. With this configuration, the relative attitude of the trolley with respect to the guided vehicle body can be easily detected simply by acquiring the state of the characteristic point of the trolley. Furthermore, since there is no need to provide a sensor for detecting the attitude on the trolley, the relative attitude of the trolley can be detected while maintaining a simple structure for the trolley.

In this case, preferably, the feature points of the trolley include markers provided on the trolley. With this configuration, unlike when the shape of the corners of the trolley or the like is used as a feature point, it is possible to detect the relative orientation of the trolley with respect to the transport vehicle body using dedicated markers. As a result, it is possible to detect the relative orientation of the trolley with respect to the transport vehicle body with high accuracy.

In the method for controlling travel of an autonomous transport vehicle according to the first aspect, preferably, the relative attitude of the dolly with respect to the transport vehicle body includes information on the inclination angle of the dolly with respect to the transport vehicle body, and the step of controlling the travel speed of the transport vehicle body includes a step of controlling the travel speed of the transport vehicle body based on the information on the inclination angle of the dolly with respect to the transport vehicle body. With this configuration, the travel speed of the transport vehicle body can be precisely controlled based on the information on the inclination angle of the dolly with respect to the transport vehicle body.

In this case, preferably, the step of controlling the travel speed of the transport vehicle body includes a step of controlling the travel speed of the transport vehicle body so that the transport vehicle body decelerates based on information about the inclination angle of the dolly relative to the transport vehicle body in a horizontal plane. With this configuration, if a change occurs in the inclination angle of the dolly relative to the transport vehicle body in a horizontal plane when moving around a curved section such as a corner, the travel speed of the transport vehicle body can be appropriately decelerated in accordance with the change in the inclination angle of the dolly relative to the transport vehicle body in the horizontal plane. As a result, the travel speed of the transport vehicle body can be precisely controlled when moving around a curved section.

In the above-mentioned configuration in which the relative attitude of the dolly with respect to the transport vehicle body includes information on the inclination angle of the dolly with respect to the transport vehicle body, preferably, the step of controlling the travel speed of the transport vehicle body includes a step of controlling the travel speed of the transport vehicle body so that the transport vehicle body stops based on information on the inclination angle of the dolly with respect to the transport vehicle body in a vertical plane. With this configuration, the transport vehicle body can be stopped when, for example, an abnormality occurs in the attitude of the dolly due to an abnormality in the wheels of the dolly, causing a change in the inclination angle of the dolly with respect to the transport vehicle body in a vertical plane. This makes it possible to prevent the dolly from tipping over when towing it with the transport vehicle body.

In this case, preferably, the method further includes a step of acquiring information on the inclination angle of the transport vehicle body in the vertical plane, and the step of controlling the travel speed of the transport vehicle body includes a step of controlling the travel speed of the transport vehicle body so that the transport vehicle body stops based on information on the inclination angle of the dolly relative to the transport vehicle body in the vertical plane and information on the inclination angle of the transport vehicle body in the vertical plane. With this configuration, the transport vehicle body can be controlled to stop based not only on the inclination angle of the dolly relative to the transport vehicle body in the vertical plane, but also on the inclination angle of the transport vehicle body in the vertical plane. As a result, the transport vehicle body can be controlled to stop with high accuracy.

In the method for controlling the travel of an autonomous guided vehicle according to the first aspect, the step of controlling the travel speed of the guided vehicle body preferably includes a step of controlling the travel speed of the guided vehicle body in consideration of at least one of the shape of the carriage, the weight of the carriage, and the position of the center of gravity of the carriage. With this configuration, the travel speed of the guided vehicle body can be controlled in consideration of at least one of the shape of the carriage, the weight of the carriage, and the position of the center of gravity of the carriage, which differ depending on the type of carriage. As a result, the travel speed of the guided vehicle body can be appropriately controlled depending on the type of carriage.

In the method for controlling the travel of an autonomous guided vehicle according to the first aspect , the step of controlling the relative attitude of the carriage with respect to the carriage body in a horizontal plane preferably includes a step of controlling the relative attitude of the carriage with respect to the carriage body in a horizontal plane by driving the coupling unit with the drive unit when the carriage body turns so as to cancel the movement of the carriage due to inertia. With this configuration, it is possible to suppress the carriage from moving like a swing due to inertia when the carriage body turns. As a result, it is possible to move the carriage compactly when the carriage body turns. This makes it easy to perform travel operations such as turning and turning around at narrow bends.

In the method for controlling travel of an autonomous guided vehicle according to the first aspect , the vehicle body preferably further includes a stopper for limiting movement of the coupling portion, and the step of controlling the relative attitude of the carriage with respect to the vehicle body in the horizontal plane includes a step of controlling the relative attitude of the carriage with respect to the vehicle body in the horizontal plane by driving the coupling portion with the drive unit within an angle range limited by the stopper. With this configuration, when the coupling portion is driven by the drive unit, the coupling portion can be driven so as not to come into contact with the stopper. As a result, when the coupling portion is driven by the drive unit, it is possible to suppress a load being applied to both the coupling portion and the stopper due to contact between the coupling portion and the stopper. In addition, by providing a stopper, the movement of the coupling portion can be limited. As a result, by limiting the movement of the coupling portion, the movement of the carriage can be limited to a predetermined range.

In the method for controlling the travel of an autonomous guided vehicle according to the first aspect, the step of controlling the travel speed of the guided vehicle body preferably includes a step of acquiring a correction time required to correct the relative attitude of the carriage with respect to the guided vehicle body by controlling the travel speed of the guided vehicle body, and a step of detecting a travel abnormality based on a comparison between the correction time and a reference correction time. With this configuration, it is possible to detect a travel abnormality caused by an abnormality such as an abnormality in the floor surface or an abnormality in the wheels of the carriage. As a result, when a travel abnormality is detected, the travel abnormality can be quickly resolved.

In this case, preferably, the step of controlling the traveling speed of the transport vehicle body further includes a step of learning the reference correction time based on the correction time. With this configuration, the reference correction time can be updated by learning. As a result, the updated reference correction time can be used to more accurately detect abnormalities in traveling.

In the above configuration for learning the reference correction time, preferably, the step of learning the reference correction time includes a step of learning the reference correction time for each of the relative posture of the dolly with respect to the transport vehicle body, the travel speed of the transport vehicle body, the weight of the dolly, or the traveling direction of the transport vehicle body. With this configuration, the reference correction time can be learned by dividing the cases into different cases. As a result, the divided reference correction time can be used to more accurately detect abnormalities in the travel depending on each individual case.

In the method for controlling travel of an autonomous transport vehicle according to the first aspect, preferably, the method further includes a step of moving the transport vehicle body to a coupling position with the cart when coupling the transport vehicle body and the cart based on the state of the cart. With this configuration, the transport vehicle body and the cart can be automatically coupled. As a result, it is possible to automate the process from coupling the transport vehicle body and the cart to towing the cart by the transport vehicle body.

An autonomous guided vehicle according to a second aspect of the present invention is an autonomous guided vehicle that travels autonomously by towing a cart, and is equipped with a status acquisition unit that acquires the status of the cart, and a control unit that detects the relative attitude of the cart to the guided vehicle body based on the status of the cart acquired by the status acquisition unit, and controls the traveling speed of the guided vehicle body based on the relative attitude of the cart to the guided vehicle body, wherein the guided vehicle body or the cart includes a connecting unit that connects the guided vehicle body and the cart, and the guided vehicle body includes a drive unit that drives the connecting unit, and the control unit controls the relative attitude of the cart to the guided vehicle body in a horizontal plane by driving the connecting unit with the drive unit when the guided vehicle body is towing the cart, so as to counteract movement of the cart due to inertia .

In the autonomous transport vehicle according to the second aspect of the present invention, as described above, a control unit is provided that detects the relative attitude of the dolly with respect to the transport vehicle body based on the state of the dolly acquired by the state acquisition unit, and controls the travel speed of the transport vehicle body based on the relative attitude of the dolly with respect to the transport vehicle body. As a result, when a change in the relative attitude of the dolly with respect to the transport vehicle body occurs when moving around a curved point such as a corner, the travel speed of the transport vehicle body can be appropriately changed in response to the change in the relative attitude of the dolly with respect to the transport vehicle body. As a result, unlike the case where the travel speed of the transport vehicle body is uniformly reduced when the dolly is towed by the transport vehicle body, an unnecessary decrease in the travel speed does not occur. This makes it possible to provide an autonomous transport vehicle that can increase productivity while suppressing the dolly from tipping over at a curved point when the dolly is towed by the transport vehicle body. In addition, when an abnormality occurs in the attitude of the dolly when the dolly is towed by the transport vehicle body, the travel speed of the transport vehicle body can also be appropriately changed in response to the change in the relative attitude of the dolly with respect to the transport vehicle body caused by the abnormality in the attitude of the dolly. This also makes it possible to suppress the dolly from tipping over when the dolly is towed by the transport vehicle body.

In the autonomous transport vehicle according to the second aspect, preferably, the state acquisition unit is configured to acquire the state of the feature points of the trolley, and the control unit is configured to detect the relative attitude of the trolley with respect to the transport vehicle body based on the state of the feature points of the trolley acquired by the state acquisition unit. With this configuration, the relative attitude of the trolley with respect to the transport vehicle body can be easily detected simply by acquiring the state of the feature points of the trolley. Also, since there is no need to provide the trolley with a sensor for detecting the attitude, the relative attitude of the trolley can be detected while maintaining a simple structure.

A transport system according to a third aspect of the present invention comprises a cart, an autonomous transport vehicle that travels autonomously by towing the cart, and a control device that transmits commands to the autonomous transport vehicle, wherein the autonomous transport vehicle includes a status acquisition unit that acquires the status of the cart, and a transport vehicle control unit that detects the relative attitude of the cart to the transport vehicle body based on the status of the cart acquired by the status acquisition unit, and controls the traveling speed of the transport vehicle body based on the relative attitude of the cart to the transport vehicle body, wherein the transport vehicle body or the cart includes a coupling unit that connects the transport vehicle body and the cart, and the transport vehicle body includes a drive unit that drives the coupling unit, and when the cart is towed by the transport vehicle body, the transport vehicle control unit drives the coupling unit with the drive unit, thereby controlling the relative attitude of the cart to the transport vehicle body in a horizontal plane so as to cancel out movement of the cart due to inertia .

In the transport system according to the third aspect of the present invention, as described above, a transport vehicle control unit is provided that detects the relative attitude of the cart with respect to the transport vehicle body based on the state of the cart acquired by the state acquisition unit, and controls the travel speed of the transport vehicle body based on the relative attitude of the cart with respect to the transport vehicle body. As a result, when a change in the relative attitude of the cart with respect to the transport vehicle body occurs when moving around a curved point such as a corner, the travel speed of the transport vehicle body can be appropriately changed in response to the change in the relative attitude of the cart with respect to the transport vehicle body. As a result, unlike the case where the travel speed of the transport vehicle body is uniformly reduced when the cart is towed by the transport vehicle body, an unnecessary decrease in the travel speed does not occur. This makes it possible to provide a transport system that can increase productivity while suppressing the cart from tipping over at a curved point when the cart is towed by the transport vehicle body. In addition, when an abnormality occurs in the attitude of the cart when the cart is towed by the transport vehicle body, the travel speed of the transport vehicle body can also be appropriately changed in response to the change in the relative attitude of the cart with respect to the transport vehicle body caused by the abnormality in the attitude of the cart. This also makes it possible to suppress the cart from tipping over when the cart is towed by the transport vehicle body.

In the transport system according to the third aspect, preferably, the status acquisition unit is configured to acquire the status of the feature points of the trolley, and the transport vehicle control unit is configured to detect the relative attitude of the trolley with respect to the transport vehicle body based on the status of the feature points of the trolley acquired by the status acquisition unit. With this configuration, the relative attitude of the trolley with respect to the transport vehicle body can be easily detected simply by acquiring the status of the feature points of the trolley. In addition, since there is no need to provide a sensor for detecting the attitude on the trolley, the relative attitude of the trolley can be detected while maintaining a simple structure.

According to the present invention, as described above, it is possible to provide a driving control method for an autonomous guided vehicle, an autonomous guided vehicle, and a transport system that can increase productivity while preventing the cart from tipping over at bending points when the cart is towed by the transport vehicle body.

FIG. 1 is a block diagram illustrating a transport system according to one embodiment. FIG. 2 is a block diagram illustrating a server according to one embodiment. FIG. 1 is a block diagram illustrating an autonomous guided vehicle according to one embodiment. 10 is a schematic diagram for explaining acquisition of a state of a feature point of a cart according to an embodiment; FIG. FIG. 2 is a schematic diagram illustrating characteristic points of a cart according to an embodiment. 1A to 1C are schematic diagrams illustrating a state in which a trolley is towed straight, a state in which the trolley is towed tilted in a horizontal plane, and a state in which the trolley is towed tilted in a circular plane in one embodiment. 5A and 5B are schematic diagrams for explaining drive control of a connecting portion according to one embodiment. 5 is a schematic diagram for explaining a correction time during travel speed control according to an embodiment. FIG. FIG. 4 is a schematic diagram for explaining an area during travel speed control according to one embodiment. FIG. 1 is a diagram for explaining automatic coupling control of an autonomous guided vehicle according to an embodiment. 11 is a flowchart for explaining an automatic coupling process of an autonomous guided vehicle according to an embodiment. 11 is a flowchart for explaining a speed control process for an autonomous guided vehicle according to an embodiment. This is a continuation of the flowchart in Figure 12 . 11 is a flowchart for explaining a process for stopping travel of an autonomous guided vehicle according to an embodiment. 11 is a flowchart for explaining a joint control process for an autonomous guided vehicle according to an embodiment. 13 is a schematic diagram for explaining acquisition of a state of a feature point of a cart according to a modified example of an embodiment. FIG.

Below, an embodiment of the present invention is described with reference to the drawings.

(Configuration of circuit board manufacturing system)
The configuration of a transport system 100 according to an embodiment of the present invention will be described with reference to FIG.

The conveying system 100 according to this embodiment is a system used in a manufacturing factory. The manufacturing factory in which the conveying system 100 is used is not particularly limited, and may be, for example, a circuit board manufacturing factory that manufactures circuit boards by mounting electronic components on printed circuit boards. As shown in FIG. 1, the conveying system 100 includes a server 10, an autonomous guided vehicle 20, and a cart 30. Note that while FIG. 1 illustrates one autonomous guided vehicle 20 and one cart 30, in an actual manufacturing factory, multiple autonomous guided vehicles 20 and multiple carts 30 are provided. The server 10 is also an example of a "control device" in the claims.

(Server configuration)
As shown in Fig. 1, the server 10 is configured to transmit commands to the autonomous guided vehicle 20. The server 10 is configured, for example, by a personal computer. As shown in Fig. 2, the server 10 includes a control unit 11, a storage unit 12, a display unit 13, an operation unit 14, and a communication unit 15.

The control unit 11 is a control circuit that controls each part of the server 10. The control unit 11 includes a CPU (Central Processing Unit) and a memory. The control unit 11 is configured to control the transmission of commands to the autonomous guided vehicle 20 based on the manufacturing plan and user input, etc. The memory unit 12 includes a rewritable storage medium such as a flash memory, and is configured to be able to store various types of information. The memory unit 12 stores information on the manufacturing plan, information on the autonomous guided vehicle 20, information on the trolley 30, etc.

The display unit 13 includes, for example, a liquid crystal display unit, and is configured to be capable of displaying various types of information. The operation unit 14 includes input units such as a mouse and keyboard, and is configured to be capable of receiving input operations from a user. The communication unit 15 is configured to be capable of transmitting and receiving information to and from the autonomous guided vehicle 20. The communication unit 15 is a wireless communication unit for wireless communication. The server 10 is connected to the autonomous guided vehicle 20 via a network so as to be capable of communicating with the autonomous guided vehicle 20.

(Configuration of autonomous guided vehicles)
Next, the configuration of the autonomous guided vehicle 20 will be described.

The autonomous guided vehicle 20 is configured to travel autonomously by towing the cart 30. Specifically, the autonomous guided vehicle 20 is configured to transport items used in a manufacturing plant by towing the cart 30 and traveling autonomously.

3 and 4, the autonomous guided vehicle 20 includes a plurality of (four) drive wheels 20a, a plurality of (four) drive wheel motors 20b, a drive wheel control unit 20c, a coupling unit 20d, a coupling motor 20e, and a pair of stoppers 20f. The autonomous guided vehicle 20 also includes a control unit 21, an imaging unit 22, a communication unit 23, a battery 24, a tilt sensor 25, and a memory unit 26. These components are provided in the guided vehicle body 27. For convenience, FIG. 3 illustrates the plurality of (four) drive wheels 20a and the plurality of (four) drive wheel motors 20b one by one. The control unit 21 is an example of a "guide vehicle control unit" in the claims. The coupling motor 20e is an example of a "drive unit" in the claims. The imaging unit 22 is an example of a "status acquisition unit" in the claims.

The multiple drive wheels 20a are configured to drive the transport vehicle body 27. The multiple drive wheels 20a are configured to be able to drive the transport vehicle body 27 in a straight line or turn. The multiple drive wheels 20a are provided on the left and right sides of the transport vehicle body 27, two on each side. The multiple drive wheel motors 20b are configured to drive the multiple drive wheels 20a. The multiple drive wheel motors 20b are provided to correspond to the multiple drive wheels 20a. The drive wheel control unit 20c is configured to control the multiple drive wheel motors 20b based on commands from the control unit 21, and to control the travel direction and travel speed of the transport vehicle body 27 driven by the multiple drive wheels 20a.

The connecting part 20d is a connecting member that connects the transport vehicle body 27 and the cart 30. The connecting part 20d is configured to connect the transport vehicle body 27 and the cart 30 so as to be rotatable around a rotation axis C extending in the vertical direction (Z direction) with the connecting point on the transport vehicle body 27 side as the rotation center. The connecting part motor 20e is configured to drive the connecting part 20d. The connecting part motor 20e is configured to rotate the connecting part 20d around the rotation axis C based on a command from the control unit 21. The pair of stoppers 20f is configured to limit the movement of the connecting part 20d. The pair of stoppers 20f is provided on both sides of the connecting part 20d. The pair of stoppers 20f is provided in a V-shape, sandwiching the connecting part 20d.

The control unit 21 is configured to control each part of the autonomous guided vehicle 20. The control unit 21 includes a CPU (Central Processing Unit) and a memory. The control unit 21 is configured to control the autonomous driving of the autonomous guided vehicle 20 by controlling the drive wheel motor 20b via the drive wheel control unit 20c.

The control unit 21 is also configured to autonomously drive the autonomous guided vehicle 20 to the destination based on a command from the server 10. For example, the control unit 21 autonomously drives the autonomous guided vehicle 20 to a waiting position for the cart 30 based on a command from the server 10. For example, the control unit 21 autonomously drives the autonomous guided vehicle 20 to a warehouse in which the items to be transported are stored, while towing the cart 30, based on a command from the server 10. For example, the control unit 21 autonomously drives the autonomous guided vehicle 20 to a transport position for the items, while towing the cart 30 containing the items to be transported, based on a command from the server 10.

The imaging unit 22 is configured to acquire the state of the trolley 30. Specifically, the imaging unit 22 is configured to acquire the state of the feature points 31 of the trolley 30. The imaging unit 22 is configured to acquire the state of the feature points 31 of the trolley 30 as an imaging result by imaging the feature points 31 of the trolley 30. The imaging unit 22 includes a camera. The imaging unit 22 is provided at a position where the imaging unit 22 can image the feature points 31 of the trolley 30. The imaging unit 22 is provided on the part of the transport vehicle body 27 on the trolley 30 side.

The communication unit 23 is configured to be able to transmit and receive information to and from the server 10. The communication unit 23 is a wireless communication unit for wireless communication. The autonomous guided vehicle 20 is connected to the server 10 via a network so as to be able to communicate with the server 10. The battery 24 is configured to supply power to each part of the autonomous guided vehicle 20. The battery 24 includes a rechargeable battery. The autonomous guided vehicle 20 travels autonomously using the power of the battery 24. The tilt sensor 25 is configured to obtain the tilt angle of the autonomous guided vehicle 20 in a vertical plane and transmit it to the control unit 21. The tilt sensor 25 includes, for example, a gyro sensor. The memory unit 26 includes a rewritable storage medium such as a flash memory, and is configured to be able to store various information. The memory unit 26 stores information on the autonomous guided vehicle 20, information on the trolley 30, and the like.

(Truck configuration)
Next, the configuration of the carriage 30 will be described.

The trolley 30 is configured to accommodate items used in a manufacturing plant. As shown in FIG. 4, the trolley 30 includes a feature 31, a storage section 32, and a plurality (four) of wheels 33.

The feature point 31 includes a marker provided on the cart 30. The marker is not particularly limited, but can be formed, for example, from sheet metal. The feature point 31 is provided at a position where it can be imaged by the imaging unit 22 of the autonomous guided vehicle 20. The feature point 31 is provided on the part of the cart 30 on the autonomous guided vehicle 20 side. As shown in FIG. 5, the feature point 31 is patterned. If the feature point 31 is made of sheet metal, the pattern of the feature point 31 can be formed by a laser. The pattern of the feature point 31 is configured so that the shape seen from the autonomous guided vehicle 20 changes according to the change in the relative attitude of the cart 30 with respect to the carrier body 27. The pattern of the feature point 31 is configured by a two-dimensional code including the identification information of the cart 30. The control unit 21 of the autonomous guided vehicle 20 can acquire the identification information of the cart 30 based on the image capturing result of the feature point 31 by the imaging unit 22. In addition, the control unit 21 of the autonomous guided vehicle 20 can obtain information about the cart 30, such as the shape of the cart 30, the weight of the cart 30, and the center of gravity position of the cart 30, from the server 10 based on the identification information of the cart 30.

As shown in FIG. 4, the storage section 32 is configured to be able to store items. The storage section 32 is formed in a concave shape. The multiple wheels 33 are configured to move the cart 30 by being towed by the autonomous guided vehicle 20. The multiple wheels 33 are provided as swivel wheels. The multiple wheels 33 are provided on the left and right sides of the cart 30, two on each side.

(Control of the travel speed of the transport vehicle body)
Next, the control of the traveling speed of the transport vehicle body 27 will be described.

6, in this embodiment, the control unit 21 is configured to detect the relative attitude of the cart 30 with respect to the transport vehicle body 27 based on the state of the cart 30 acquired by the imaging unit 22, and to control the traveling speed of the transport vehicle body 27 based on the relative attitude of the cart 30 with respect to the transport vehicle body 27. Specifically, the control unit 21 is configured to detect the relative attitude of the cart 30 with respect to the transport vehicle body 27 based on the state of the feature point 31 of the cart 30 acquired by the imaging unit 22.

When the carriage 30 is towed straight by the transport vehicle body 27, the feature point 31 is located in the center of the image and is not tilted. When the carriage 30 is towed by the transport vehicle body 27 while tilted in the horizontal plane, the feature point 31 is located in a position shifted from the center of the image and is tilted in the depth direction. When the carriage 30 is towed by the transport vehicle body 27 while tilted in the vertical plane, the feature point 31 is located in the center of the image and is tilted in the plane perpendicular to the depth direction. By utilizing the change in the state of these feature points 31, the relative attitude of the carriage 30 with respect to the transport vehicle body 27 can be detected. In FIG. 6, the carriage 30 is exaggerated in the tilted state in the vertical plane for ease of understanding.

The relative attitude of the trolley 30 with respect to the transport vehicle body 27 includes information on the inclination angle of the trolley 30 with respect to the transport vehicle body 27. Specifically, the relative attitude of the trolley 30 with respect to the transport vehicle body 27 includes information on the inclination angle γ of the trolley 30 with respect to the transport vehicle body 27 in a horizontal plane, and information on the inclination angle θ of the trolley 30 with respect to the transport vehicle body 27 in a vertical plane.

The control unit 21 is configured to control the traveling speed of the transport vehicle body 27 based on information on the inclination angle of the dolly 30 relative to the transport vehicle body 27. Specifically, the control unit 21 is configured to control the traveling speed of the transport vehicle body 27 based on information on the inclination angle γ of the dolly 30 relative to the transport vehicle body 27 in a horizontal plane so that the transport vehicle body 27 decelerates. More specifically, the control unit 21 is configured to control the traveling speed of the transport vehicle body 27 by the following formula (1). The control unit 21 is configured to control the traveling speed of the transport vehicle body 27 by the following formula (1) so that the traveling speed decreases as the inclination angle γ increases.
Vc=V×{1-k×sin(γ)}...(1)
Where:
Vc: correction speed V: normal speed k: correction coefficient γ: inclination angle of the carriage with respect to the transport vehicle body in the horizontal plane.

The normal speed V and the correction coefficient k can be determined in advance through experiments, etc. The normal speed V is not particularly limited, but can be, for example, about 2 m/s. The correction coefficient k is also not particularly limited, but can be, for example, a value that makes the correction speed Vc 1 m/s or less. The normal speed V is the traveling speed of the transport vehicle body 27 when the carriage 30 is towed straight by the transport vehicle body 27.

In addition, the control unit 21 is configured to control the travel speed of the transport vehicle body 27 based on information on the inclination angle θ of the cart 30 relative to the transport vehicle body 27 in the vertical plane so that the transport vehicle body 27 stops. Specifically, the control unit 21 is configured to control the travel speed of the transport vehicle body 27 based on information on the inclination angle θ of the cart 30 relative to the transport vehicle body 27 in the vertical plane and information on the inclination angle δ of the transport vehicle body 27 in the vertical plane acquired by the inclination sensor 25 so that the transport vehicle body 27 stops.

First, the control unit 21 obtains the difference (θ-δ) between the tilt angle θ and the tilt angle δ as the true tilt angle θt of the cart 30 in the vertical plane. Then, the control unit 21 detects whether the true tilt angle θt exceeds a reference angle (threshold value). When the control unit 21 detects that the true tilt angle θt exceeds the reference angle, it controls the travel speed of the transport vehicle body 27 so that the transport vehicle body 27 stops. At this time, the control unit 21 controls the travel speed of the transport vehicle body 27 so that the transport vehicle body 27 gradually decelerates and stops. Furthermore, when the control unit 21 detects that the true tilt angle θt does not exceed the reference angle, it controls the transport vehicle body 27 to continue traveling. The reference angle can be determined in advance by experiment, etc.

In addition, in this embodiment, the control unit 21 is configured to control the traveling speed of the transport vehicle body 27 by taking into account at least one of the shape of the cart 30, the weight of the cart 30, and the position of the center of gravity of the cart 30. For example, the control unit 21 takes into account the shape of the cart 30 and reduces the traveling speed of the transport vehicle body 27 when the width of the cart 30 is large compared to when the cart 30 has a small width. Similarly, the control unit 21 takes into account the shape of the cart 30 and increases the traveling speed of the transport vehicle body 27 when the width of the cart 30 is small compared to when the cart 30 has a large width.

In addition, for example, the control unit 21 takes into account the weight of the trolley 30 and reduces the travel speed of the transport vehicle main body 27 when the weight of the trolley 30 is large, compared to when the weight of the trolley 30 is small. Similarly, the control unit 21 takes into account the weight of the trolley 30 and increases the travel speed of the transport vehicle main body 27 when the weight of the trolley 30 is small, compared to when the weight of the trolley 30 is large.

In addition, for example, the control unit 21 takes into consideration the position of the center of gravity of the trolley 30 and reduces the travel speed of the transport vehicle body 27 when turning counterclockwise compared to when turning clockwise when the center of gravity of the trolley 30 is on the left side. Similarly, the control unit 21 takes into consideration the position of the center of gravity of the trolley 30 and reduces the travel speed of the transport vehicle body 27 when turning clockwise compared to when turning counterclockwise when the center of gravity of the trolley 30 is on the right side.

(Drive control of connecting part)
Next, drive control of the connecting portion 20d will be described.

7, the control unit 21 is configured to control the relative attitude of the cart 30 to the transport vehicle body 27 in the horizontal plane by driving (rotating) the coupling part 20d by the coupling part motor 20e when the transport vehicle body 27 is towing the cart 30. Specifically, the control unit 21 is configured to control the relative attitude of the cart 30 to the transport vehicle body 27 in the horizontal plane by driving (rotating) the coupling part 20d by the coupling part motor 20e when the transport vehicle body 27 turns, so as to cancel out the movement of the cart 30 due to inertia.

Here, the inertial force acting on the carriage 30 when the transporting vehicle body 27 turns can be expressed by the following formula (2).
Fj=m×a...(2)
Where:
Fj: inertial force acting on the cart, m: weight of the cart, a: acceleration in the rotational direction of the cart.

When an item is being transported, the weight m used is the sum of the weight of the cart 30 and the weight of the item, and when an item is not being transported, the weight of the cart 30 is used. The weight of the cart 30 can be obtained from the server 10 based on the identification information of the cart 30. The weight of the item can be obtained by identifying the item based on the contents of the command (task contents) from the server 10. The acceleration a can be obtained from the rotation speed of the transport vehicle body 27 using a conversion table. Alternatively, the acceleration a can be obtained from the change over time in the state of the feature point 31 of the cart 30 acquired by the imaging unit 22.

In addition, the kinetic friction force acting on the cart 30 can be expressed by the following equation (3).
F=μ×m×g...(3)
Where:
F: kinetic friction force acting on the cart, μ: kinetic friction coefficient, m: weight of the cart, g: gravitational acceleration.

The dynamic friction coefficient μ can be obtained by the user inputting the dynamic friction coefficient of the floor surface. The weight m can be obtained in the same manner as in the above formula (2). The gravitational acceleration g can be obtained as a known value.

When the transport vehicle body 27 turns, the cart 30 is swung in the rotational direction by a force determined by the inertial force Fj calculated by the above formula (2) and the kinetic friction force F calculated by the above formula (3). For this reason, the control unit 21 determines the drive direction (the direction opposite to the direction in which inertia acts) and drive distance (drive angle) of the connecting part 20d so as to cancel the difference (Fg-F) between the inertial force Fg and the kinetic friction force F. The control unit 21 then controls the driving of the connecting part 20d by the connecting part motor 20e so as to rotate the connecting part 20d by the determined drive distance (drive angle) in the determined drive direction.

In this embodiment, the control unit 21 is configured to control the relative attitude of the cart 30 with respect to the transport vehicle main body 27 in the horizontal plane by driving (rotating) the coupling part 20d by the coupling part motor 20e within an angle range limited by the stopper 20f. The control unit 21 is configured to drive (rotate) the coupling part 20d by the coupling part motor 20e within a range in which the coupling part 20d does not come into contact with the stopper 20f.

(Correction time when controlling driving speed)
Next, the correction time when controlling the traveling speed of the transport vehicle body 27 will be described.

As shown in Fig. 8, the control unit 21 is configured to acquire a correction time T required to correct the relative posture of the carriage 30 with respect to the transport vehicle body 27 by controlling the travel speed of the transport vehicle body 27. The control unit 21 is also configured to detect a travel abnormality based on a comparison between the correction time T and a reference correction time. Specifically, the control unit 21 is configured to detect a travel abnormality by the following formula (4). The control unit 21 is configured to detect a travel abnormality when the correction time T is outside (below or above) the normal range defined by the following formula (4).
Te-α<T<Te+α...(4)
Where:
Te: reference correction time T: correction time α: constant.

The reference correction time Te and the correction time T will be described later. The constant α can be determined in advance by experiment or the like.

As shown in Fig. 9, multiple areas A (four in Fig. 9) are set for correcting the relative posture of the trolley 30 with respect to the transport vehicle body 27. The multiple areas A are set as ranges of different inclination angles γ. For example, area 1 is set as a range of inclination angle γ of 0 degrees or more and less than 5 degrees, area 2 is set as a range of inclination angle γ of 5 degrees or more and less than 10 degrees, area 3 is set as a range of inclination angle γ of 10 degrees or more and less than 15 degrees, and area 4 is set as a range of inclination angle γ of 15 degrees or more and less than 20 degrees.

The control unit 21 is configured to control the change of the travel speed of the transport vehicle body 27 when the area A transitions from the previous area A to a different area A. The control unit 21 is also configured to obtain the time until the area A transitions from the previous area A to the different area A as a correction time T and store it in the memory unit 26.

Furthermore, in this embodiment, the control unit 21 is configured to learn the reference correction time Te based on the correction time T. Specifically, the control unit 21 is configured to learn and update the reference correction time Te by the following formula (5). The control unit 21 is configured to learn and update the reference correction time Te as an average value of multiple correction times T by the following formula (5). The control unit 21 is configured to acquire the reference correction time Te as an expected correction completion time when correction is expected to be completed by the following formula (5).
Te=ΣTn/n...(5)
Where:
Te: Reference correction time Tn: Correction time acquired for the nth time n: Number of correction time
It is.

In addition, in this embodiment, the control unit 21 is configured to learn the reference correction time Te for each of the relative posture (area A) of the carriage 30 with respect to the transport vehicle body 27, the travel speed of the transport vehicle body 27, the weight of the carriage 30, or the traveling direction of the transport vehicle body 27. For this reason, when the area A transitions from the previous area A to a different area A, the control unit 21 is configured to store the area A (tilt angle γ), the travel speed of the transport vehicle body 27, the weight of the carriage 30, and the traveling direction of the transport vehicle body 27 (whether it is a right turn or a left turn) in the memory unit 26 in association with the correction time T. As a result, the correction time T is acquired for each of the area A, the travel speed of the transport vehicle body 27, the weight of the carriage 30, or the traveling direction of the transport vehicle body 27. In addition, the reference correction time Te is learned for each of the area A, the travel speed of the transport vehicle body 27, the weight of the carriage 30, or the traveling direction of the transport vehicle body 27.

The control unit 21 is also configured to learn the correction coefficient k in the above formula (1) based on the correction time T. Specifically, the control unit 21 is configured to acquire the correction coefficient k as a random number in a predetermined range. The control unit 21 is also configured to learn and update the range of the random number of the correction coefficient k, centered on the value of the correction coefficient k that results in a smaller correction time T. This makes it possible to converge the range of the random number of the correction coefficient k to an appropriate range.

(Automatic coupling control of autonomous guided vehicles)
Next, the automatic coupling control of the autonomous guided vehicle 20 will be described.

10, the control unit 21 is configured to move the transport vehicle body 27 to a coupling position with the trolley 30 when the transport vehicle body 27 and the trolley 30 are coupled, based on the state of the trolley 30 acquired by the imaging unit 22. Specifically, the control unit 21 is configured to move the transport vehicle body 27 to a coupling position with the trolley 30 when the transport vehicle body 27 and the trolley 30 are coupled, based on the state of the feature point 31 of the trolley 30 acquired by the imaging unit 22.

The control unit 21 is configured to recognize the state of the characteristic point 31 of the trolley 30 by capturing an image using the imaging unit 22. The control unit 21 is configured to bring the transport vehicle main body 27 close to the unconnected trolley 30, using the state of the characteristic point 31 of the trolley 30 as a landmark. The control unit 21 is configured to control the connection of the transport vehicle main body 27 and the trolley 30 by the connection unit 20d when the transport vehicle main body 27 is moved to a connection position with the trolley 30. The control unit 21 is configured to tow the trolley 30 connected by the connection unit 20d to travel autonomously.

(Automatic coupling process for autonomous guided vehicles)
Next, the automatic coupling process of the autonomous guided vehicle 20 of this embodiment will be described with reference to a flowchart. Note that each process in the flowchart is performed by the control unit 21.

As shown in FIG. 11, first, in step S101, it is detected whether or not a towing command for the trolley 30 has been received from the server 10. The towing command for the trolley 30 includes information on the items to be loaded onto the trolley 30. If it is detected that a towing command for the trolley 30 has not been received, the process of step S101 is repeated. Also, if it is detected that a towing command for the trolley 30 has been received, the process proceeds to step S102.

Then, in step S102, the transport vehicle body 27 is moved to the designated position instructed by the server 10.

Then, in step S103, the characteristic points 31 of the trolley 30 are recognized by capturing an image using the imaging unit 22.

Then, in step S104, information about the trolley 30 (such as the shape of the trolley 30, the weight of the trolley 30, and the position of the center of gravity of the trolley 30) is acquired based on the characteristic points 31 of the trolley 30. Specifically, in step S104, identification information about the trolley 30 is acquired from the characteristic points 31 of the trolley 30. Then, information about the trolley 30 is acquired from the server 10 based on the identification information about the trolley 30.

Then, in step S105, the transport vehicle body 27 is brought closer to the cart 30 using the characteristic point 31 of the cart 30 as a landmark.

Then, in step S106, it is detected whether the transport vehicle body 27 has moved to the coupling position with the dolly 30. If it is detected that the transport vehicle body 27 has not moved to the coupling position with the dolly 30, the processing of step S106 is repeated. If it is detected that the transport vehicle body 27 has moved to the coupling position with the dolly 30, the processing proceeds to step S107.

Then, in step S107, the transport vehicle body 27 and the dolly 30 are connected by the connecting portion 20d. Then, in step S107, the transport vehicle body 27 starts towing the dolly 30. Thereafter, the automatic connection process is terminated.

(Speed control processing for autonomous guided vehicles)
Next, a speed control process of the autonomous guided vehicle 20 according to this embodiment will be described with reference to a flowchart. Each process in the flowchart is performed by the control unit 21.

As shown in FIG. 12, first, in step S111, the state of the feature point 31 of the trolley 30 is obtained by imaging using the imaging unit 22.

Then, in step S112, the relative attitude of the cart 30 with respect to the transport vehicle body 27 in the horizontal plane is detected based on the state of the characteristic point 31 of the cart 30. In step S112, the inclination angle γ of the cart 30 with respect to the transport vehicle body 27 in the horizontal plane is detected based on the state of the characteristic point 31 of the cart 30.

Then, in step S113, it is detected whether area A is the first area A (area A in which the dolly 30 is being towed straight). If it is detected that area A is the first area A, the process proceeds to step S114.

Then, in step S114, the traveling speed of the transport vehicle body 27 is set to normal speed.

Then, in step S115, it is detected whether the transport has ended. If it is detected that the transport has ended, the speed control process is terminated. If it is detected that the transport has not ended, the process returns to step S111.

Also, if it is detected in step S113 that area A is not the first area A, proceed to step S116.

Then, in step S116, it is detected whether area A is different from the immediately preceding area A. If it is detected that area A is not different from the immediately preceding area A, the process proceeds to step S115, where the same process as described above is carried out. If it is detected that area A is different from the immediately preceding area A, the process proceeds to step S117.

13, in step S117, the travel speed of the transport vehicle body 27 is corrected according to the inclination angle γ of the carriage 30 relative to the transport vehicle body 27 in the horizontal plane. In step S117, the travel speed of the transport vehicle body 27 is corrected according to the above formula (1).

Then, in step S118, the correction time T is stored in the memory unit 26. Also, in step S118, the area A (tilt angle γ), the traveling speed of the transport vehicle body 27, the weight of the cart 30, and the traveling direction of the transport vehicle body 27 are stored in the memory unit 26 in association with the correction time T.

Then, in step S119, the correction time T is compared with the reference correction time Te.

Then, in step S120, it is detected whether the correction time T is within the normal range using the above formula (4). If it is detected that the correction time T is within the normal range, the process proceeds to step S121.

Then, in step S121, the reference correction time Te is learned and updated using the above formula (5) based on the correction time T. Then, the process proceeds to step S115, where the same process as above is performed.

Also, if it is detected in step S120 that the correction time T is not within the normal range, proceed to step S122.

Then, in step S122, an abnormality notification is made. In step S122, for example, an abnormality notification is made to the server 10. Then, the abnormality is displayed on the display unit 13 of the server 10. After that, the speed control process is terminated.

(Autonomous guided vehicle stopping process)
Next, a process for stopping the autonomous guided vehicle 20 according to the present embodiment will be described with reference to a flowchart. Each process in the flowchart is performed by the control unit 21.

As shown in FIG. 14, first, in step S131, the state of the feature point 31 of the trolley 30 is obtained by imaging using the imaging unit 22.

Then, in step S132, the relative posture of the cart 30 with respect to the transport vehicle body 27 in the vertical plane is detected based on the state of the characteristic point 31 of the cart 30. In step S132, the inclination angle θ of the cart 30 with respect to the transport vehicle body 27 in the vertical plane is detected based on the state of the characteristic point 31 of the cart 30.

Then, in step S133, the inclination sensor 25 detects the inclination angle δ of the transport vehicle body 27 in the vertical plane.

Then, in step S134, it is detected whether the true tilt angle θt (= θ-δ) of the cart 30 is abnormal. If it is detected that the true tilt angle θt of the cart 30 is not abnormal, the process proceeds to step S135.

Then, in step S135, it is detected whether the transport has ended. If it is detected that the transport has ended, the travel stop process is terminated. If it is detected that the transport has not ended, the process returns to step S131.

Also, if in step S134 it is detected that the true inclination angle θt of the trolley 30 is abnormal, the process proceeds to step S136.

Then, in step S136, the traveling of the transportation vehicle body 27 is stopped. In step S136 , the transportation vehicle body 27 is gradually decelerated and the traveling of the transportation vehicle body 27 is stopped.

Then, in step S137, an abnormality notification is made. In step S137, for example, an abnormality notification is made to the server 10. Then, the abnormality is displayed on the display unit 13 of the server 10. Thereafter, the driving stop processing is terminated.

(Control processing of the connection part of the autonomous guided vehicle)
Next, a process of controlling the joint of the autonomous guided vehicle 20 according to the present embodiment will be described with reference to a flowchart. Each process in the flowchart is performed by the control unit 21.

As shown in FIG. 15, first, in step S141, the state of the feature point 31 of the trolley 30 is obtained by imaging using the imaging unit 22.

Then, in step S142, the relative attitude of the cart 30 with respect to the transport vehicle body 27 in the horizontal plane is detected based on the state of the feature point 31 of the cart 30. In step S142, the inclination angle γ of the cart 30 with respect to the transport vehicle body 27 in the horizontal plane is detected based on the state of the feature point 31 of the cart 30.

Then, in step S143, it is detected whether area A is the first area A (area A in which the dolly 30 is being towed straight). If it is detected that area A is the first area A, the process proceeds to step S144.

Then, in step S144, it is detected whether the transport has ended. If it is detected that the transport has ended, the connection section control process is terminated. If it is detected that the transport has not ended, the process returns to step S141.

Also, if it is detected in step S143 that area A is not the first area A, proceed to step S145.

Then, in step S145, the inertial force Fj acting on the trolley 30 is obtained using the above equation (2), and the kinetic friction force F acting on the trolley 30 is obtained using the above equation (3).

Then, in step S146, the coupling motor 20e drives (rotates) the coupling 20d based on the inertial force Fj and the kinetic friction force F so as to counteract the movement of the cart 30 due to inertia. Then, the process proceeds to step S144, where the same process as described above is performed.

(Effects of this embodiment)
In this embodiment, the following effects can be obtained.

In this embodiment, as described above, the travel control method for the autonomous transport vehicle 20 includes a step of detecting the relative attitude of the cart 30 with respect to the transport vehicle body 27 based on the state of the cart 30, and a step of controlling the travel speed of the transport vehicle body 27 based on the relative attitude of the cart 30 with respect to the transport vehicle body 27. As a result, when a change in the relative attitude of the cart 30 with respect to the transport vehicle body 27 occurs during movement around a curved portion such as a corner, the travel speed of the transport vehicle body 27 can be appropriately changed according to the change in the relative attitude of the cart 30 with respect to the transport vehicle body 27. As a result, unlike the case where the travel speed of the transport vehicle body 27 is uniformly reduced when the cart 30 is towed by the transport vehicle body 27, no unnecessary reduction in the travel speed occurs. As a result, when the cart 30 is towed by the transport vehicle body 27, it is possible to increase productivity while suppressing the tipping of the cart 30 at a curved portion. In addition, if an abnormality occurs in the posture of the cart 30 when the cart 30 is towed by the transport vehicle body 27, the travel speed of the transport vehicle body 27 can be appropriately changed. This also makes it possible to prevent the cart 30 from tipping over when the cart 30 is towed by the transport vehicle body 27.

In addition, in this embodiment, as described above, the step of acquiring the state of the cart 30 includes a step of acquiring the state of the feature point 31 of the cart 30. Furthermore, the step of detecting the relative attitude of the cart 30 with respect to the transport vehicle body 27 includes a step of detecting the relative attitude of the cart 30 with respect to the transport vehicle body 27 based on the state of the feature point 31 of the cart 30. As a result, the relative attitude of the cart 30 with respect to the transport vehicle body 27 can be easily detected simply by acquiring the state of the feature point 31 of the cart 30. Furthermore, since there is no need to provide a sensor for detecting the attitude on the cart 30, the relative attitude of the cart 30 can be detected while the cart 30 has a simple structure.

In addition, in this embodiment, as described above, the feature points 31 of the cart 30 include markers provided on the cart 30. This makes it possible to detect the relative posture of the cart 30 with respect to the transport vehicle body 27 using dedicated markers, unlike the case where the shape of the corners or the like of the cart 30 is used as the feature points 31. As a result, the relative posture of the cart 30 with respect to the transport vehicle body 27 can be detected with high accuracy.

In addition, in this embodiment, as described above, the relative attitude of the cart 30 with respect to the transport vehicle body 27 includes information on the inclination angle of the cart 30 with respect to the transport vehicle body 27. Furthermore, the step of controlling the travel speed of the transport vehicle body 27 includes a step of controlling the travel speed of the transport vehicle body 27 based on the information on the inclination angle of the cart 30 with respect to the transport vehicle body 27. This makes it possible to precisely control the travel speed of the transport vehicle body 27 based on the information on the inclination angle of the cart 30 with respect to the transport vehicle body 27.

In addition, in this embodiment, as described above, the step of controlling the traveling speed of the transport vehicle body 27 includes a step of controlling the traveling speed of the transport vehicle body 27 so that the transport vehicle body 27 decelerates based on information on the inclination angle γ of the dolly 30 relative to the transport vehicle body 27 in the horizontal plane. As a result, when a change occurs in the inclination angle γ of the dolly 30 relative to the transport vehicle body 27 in the horizontal plane when moving around a curved portion such as a corner, the traveling speed of the transport vehicle body 27 can be appropriately decelerated in accordance with the change in the inclination angle γ of the dolly 30 relative to the transport vehicle body 27 in the horizontal plane. As a result, the traveling speed of the transport vehicle body 27 can be accurately controlled when moving around a curved portion.

In addition, in this embodiment, as described above, the step of controlling the travel speed of the transport vehicle body 27 includes a step of controlling the travel speed of the transport vehicle body 27 so that the transport vehicle body 27 stops based on information on the inclination angle θ of the dolly 30 relative to the transport vehicle body 27 in the vertical plane. This allows the transport vehicle body 27 to stop when, for example, an abnormality occurs in the posture of the dolly 30 due to an abnormality in the wheels 33 of the dolly 30, causing a change in the inclination angle θ of the dolly 30 relative to the transport vehicle body 27 in the vertical plane. This makes it possible to prevent the dolly 30 from tipping over when towing the dolly 30 by the transport vehicle body 27.

In addition, in this embodiment, as described above, the travel control method for the autonomous transport vehicle 20 includes a step of acquiring information on the inclination angle δ of the transport vehicle body 27 in a vertical plane. In addition, the step of controlling the travel speed of the transport vehicle body 27 includes a step of controlling the travel speed of the transport vehicle body 27 so that the transport vehicle body 27 stops based on information on the inclination angle θ of the cart 30 relative to the transport vehicle body 27 in the vertical plane and information on the inclination angle δ of the transport vehicle body 27 in the vertical plane. This makes it possible to control the transport vehicle body 27 to stop based not only on the inclination angle θ of the cart 30 relative to the transport vehicle body 27 in the vertical plane, but also on the inclination angle δ of the transport vehicle body 27 in the vertical plane. As a result, it is possible to accurately control the transport vehicle body 27 to stop.

In addition, in this embodiment, as described above, the step of controlling the traveling speed of the transport vehicle body 27 includes a step of controlling the traveling speed of the transport vehicle body 27 taking into consideration at least one of the shape of the dolly 30, the weight of the dolly 30, and the position of the center of gravity of the dolly 30. This makes it possible to control the traveling speed of the transport vehicle body 27 taking into consideration at least one of the shape of the dolly 30, the weight of the dolly 30, and the position of the center of gravity of the dolly 30, which differ depending on the type of dolly 30. As a result, it is possible to appropriately control the traveling speed of the transport vehicle body 27 depending on the type of dolly 30.

In this embodiment, as described above, the transport vehicle body 27 includes a coupling section 20d that couples the transport vehicle body 27 and the cart 30. The transport vehicle body 27 also includes a coupling section motor 20e that drives the coupling section 20d. The travel control method for the autonomous transport vehicle 20 also includes a step of controlling the relative attitude of the cart 30 to the transport vehicle body 27 in a horizontal plane by driving the coupling section 20d by the coupling section motor 20e when the transport vehicle body 27 tows the cart 30. This allows the transport vehicle body 27 to travel while controlling the relative attitude of the cart 30 to the transport vehicle body 27 in the horizontal plane. As a result, the stability of the travel of the transport vehicle body 27 can be improved compared to a case in which the relative attitude of the cart 30 to the transport vehicle body 27 in the horizontal plane cannot be controlled.

In addition, in this embodiment, as described above, the step of controlling the relative attitude of the cart 30 with respect to the transport vehicle body 27 in the horizontal plane includes a step of controlling the relative attitude of the cart 30 with respect to the transport vehicle body 27 in the horizontal plane by driving the coupling part 20d by the coupling part motor 20e when the transport vehicle body 27 turns so as to cancel the movement of the cart 30 due to inertia. This makes it possible to suppress the cart 30 from moving like a swing due to inertia when the transport vehicle body 27 turns. As a result, the cart 30 can be moved compactly when the transport vehicle body 27 turns. This makes it easy to perform traveling operations such as turning and turning around at narrow bends.

In addition, in this embodiment, as described above, the transport vehicle body 27 includes a stopper 20f that limits the movement of the connecting portion 20d. In addition, the step of controlling the relative attitude of the cart 30 with respect to the transport vehicle body 27 in the horizontal plane includes a step of controlling the relative attitude of the cart 30 with respect to the transport vehicle body 27 in the horizontal plane by driving the connecting portion 20d by the connecting portion motor 20e within the angle range limited by the stopper 20f. This allows the connecting portion 20d to be driven so as not to come into contact with the stopper 20f when the connecting portion 20d is driven by the connecting portion motor 20e. As a result, it is possible to suppress the load being applied to both the connecting portion 20d and the stopper 20f due to the connecting portion 20d and the stopper 20f coming into contact with each other when the connecting portion 20d is driven by the connecting portion motor 20e. In addition, by providing the stopper 20f, the movement of the connecting portion 20d can be limited. As a result, by limiting the movement of the connecting portion 20d, the movement of the cart 30 can be limited to a predetermined range.

In addition, in this embodiment, as described above, the step of controlling the travel speed of the transport vehicle body 27 includes a step of acquiring a correction time T required to correct the relative posture of the cart 30 with respect to the transport vehicle body 27 by controlling the travel speed of the transport vehicle body 27, and a step of detecting a travel abnormality based on a comparison between the correction time T and a reference correction time Te. This makes it possible to detect a travel abnormality caused by an abnormality such as an abnormality in the floor surface or an abnormality in the wheels of the cart 30. As a result, when a travel abnormality is detected, the travel abnormality can be quickly eliminated.

In addition, in this embodiment, as described above, the step of controlling the traveling speed of the transport vehicle body 27 includes a step of learning the reference correction time Te based on the correction time T. This makes it possible to update the reference correction time Te through learning. As a result, it is possible to more accurately detect abnormalities in traveling using the updated reference correction time Te.

In addition, in this embodiment, as described above, the step of learning the reference correction time Te includes a step of learning the reference correction time Te for each of the relative posture of the dolly 30 with respect to the transport vehicle body 27, the traveling speed of the transport vehicle body 27, the weight of the dolly 30, or the traveling direction of the transport vehicle body 27. This makes it possible to learn the reference correction time Te for each case. As a result, the reference correction time Te for each case can be used to detect traveling abnormalities with even greater accuracy depending on the individual case.

In addition, in this embodiment, as described above, the driving control method for the autonomous guided vehicle 20 includes a step of moving the guided vehicle body 27 to a coupling position with the cart 30 when the guided vehicle body 27 and the cart 30 are coupled based on the state of the cart 30. This allows the guided vehicle body 27 and the cart 30 to be automatically coupled. As a result, it is possible to automate the process from coupling the guided vehicle body 27 and the cart 30 to towing the cart 30 by the guided vehicle body 27.

(Modification)
It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications (variations) within the meaning and scope of the claims.

For example, in the above embodiment, an example is shown in which the autonomous guided vehicle has four drive wheels, but the present invention is not limited to this. In the present invention, the autonomous guided vehicle may have a number of drive wheels other than four. Furthermore, the autonomous guided vehicle may have swivel wheels in addition to the drive wheels.

In the above embodiment, an example is shown in which the autonomous guided vehicle is equipped with an imaging unit as the state acquisition unit of the present invention, but the present invention is not limited to this. In the present invention, the autonomous guided vehicle may be equipped with a state acquisition unit other than an imaging unit, such as a three-dimensional shape measurement unit using a laser. In this case, the pattern of the feature points may be formed using a three-dimensional shape such as unevenness.

In addition, in the above embodiment, an example in which one imaging unit (status acquisition unit) and one feature point are provided is shown, but the present invention is not limited to this. In the present invention, multiple status acquisition units and multiple feature points may be provided. In the modified example shown in FIG. 16, multiple (two) imaging units 22 are provided in the autonomous guided vehicle 20. Also, multiple (two) feature points 31 are provided in the cart 30. In this case, since the states of the multiple feature points 31 can be acquired, the relative posture of the cart 30 with respect to the guided vehicle body 27 can be detected more accurately based on the states of the multiple feature points 31.

In the above embodiment, an example was shown in which the feature points included markers provided on the dolly, but the present invention is not limited to this. In the present invention, the feature points may include characteristic shaped parts such as corners of the dolly.

In the above embodiment, an example is shown in which the travel speed of the transport vehicle body is controlled in response to the inclination angle of the dolly relative to the transport vehicle body in a horizontal plane, and the travel speed of the transport vehicle body is controlled in response to the inclination angle of the dolly relative to the transport vehicle body in a vertical plane, but the present invention is not limited to this. In the present invention, only one of the control of the travel speed of the transport vehicle body in response to the inclination angle of the dolly relative to the transport vehicle body in a horizontal plane and the control of the travel speed of the transport vehicle body in response to the inclination angle of the dolly relative to the transport vehicle body in a vertical plane may be performed.

In the above embodiment, an example is shown in which the transport vehicle body is stopped based on information on the inclination angle of the dolly relative to the transport vehicle body in a vertical plane and information on the inclination angle of the transport vehicle body in a vertical plane, but the present invention is not limited to this. In the present invention, the transport vehicle body may be stopped based only on information on the inclination angle of the dolly relative to the transport vehicle body in a vertical plane.

In the above embodiment, an example is shown in which the travel speed of the transport vehicle body is controlled by taking into account at least one of the shape of the cart, the weight of the cart, and the position of the center of gravity of the cart, but the present invention is not limited to this. In the present invention, the shape of the cart, the weight of the cart, and the position of the center of gravity of the cart do not need to be taken into account when controlling the travel speed of the transport vehicle body.

In addition, in the above embodiment, an example was shown in which the autonomous guided vehicle has a coupling section, but the present invention is not limited to this. In the present invention, the cart may have a coupling section.

In addition, in the above embodiment, an example was shown in which the autonomous guided vehicle was equipped with a joint motor, but the present invention is not limited to this. In the present invention, the autonomous guided vehicle does not have to be equipped with a joint motor.

In the above embodiment, an example is shown in which the autonomous guided vehicle is provided with a pair (two) of stoppers, but the present invention is not limited to this. In the present invention, the autonomous guided vehicle may be provided with multiple stoppers other than one or two. Also, the autonomous guided vehicle may not be provided with a stopper.

In addition, in the above embodiment, an example is shown in which a correction time is acquired and a driving abnormality is detected based on the correction time, but the present invention is not limited to this. In the present invention, it is not necessary to acquire a correction time.

In addition, in the above embodiment, an example is shown in which the reference correction time is learned based on the correction time, but the present invention is not limited to this. In the present invention, the reference correction time may be a fixed value.

In the above embodiment, an example is shown in which the transport vehicle body is moved to a coupling position with the dolly when the transport vehicle body and the dolly are coupled based on the state of the dolly, but the present invention is not limited to this. In the present invention, the transport vehicle body does not have to be moved to a coupling position with the dolly when the transport vehicle body and the dolly are coupled based on the state of the dolly.

In the above embodiment, for convenience of explanation, the control process is described using a flow-driven flow in which the control process is performed in sequence according to the processing flow, but the present invention is not limited to this. In the present invention, the control process may be performed by event-driven processing in which processing is performed on an event-by-event basis. In this case, the control process may be completely event-driven, or may be a combination of event-driven and flow-driven.

10 Server (control device)
20 Autonomous guided vehicle 20d Connection unit 20e Connection unit motor (drive unit)
20f stopper 21 control unit (transportation vehicle control unit)
22 Imaging unit (status acquisition unit)
27 Transport vehicle body 30 Cart 31 Feature point 100 Transport system T Correction time Te Reference correction time γ Inclination angle of the cart relative to the transport vehicle body in a horizontal plane δ Inclination angle of the transport vehicle body in a vertical plane θ Inclination angle of the cart relative to the transport vehicle body in a vertical plane

Claims (17)

A method for controlling travel of an autonomous guided vehicle that autonomously travels by towing a cart, comprising:
acquiring a state of the carriage;
detecting a relative attitude of the carriage with respect to a transport vehicle body based on a state of the carriage;
and controlling a travel speed of the transport vehicle body based on a relative attitude of the carriage with respect to the transport vehicle body,
The transport vehicle body or the dolly includes a connecting portion that connects the transport vehicle body and the dolly,
The transport vehicle body includes a drive unit that drives the coupling unit,
A method for controlling the travel of an autonomous guided vehicle, further comprising a step of controlling the relative attitude of the cart to the guided vehicle body in a horizontal plane by driving the coupling part with the drive part when the cart is towed by the guided vehicle body, so as to cancel out movement of the cart due to inertia . The step of acquiring a state of the cart includes a step of acquiring a state of a feature point of the cart,
2. The autonomous guided vehicle travel control method according to claim 1, wherein the step of detecting the relative attitude of the carriage with respect to the guided vehicle body includes a step of detecting the relative attitude of the carriage with respect to the guided vehicle body based on a state of a characteristic point of the carriage. The method for controlling travel of an autonomous guided vehicle according to claim 2, wherein the feature points of the cart include markers provided on the cart. The relative attitude of the dolly with respect to the transport vehicle body includes information on an inclination angle of the dolly with respect to the transport vehicle body,
A driving control method for an autonomous guided vehicle according to any one of claims 1 to 3, wherein the step of controlling the running speed of the guided vehicle body includes a step of controlling the running speed of the guided vehicle body based on information on the inclination angle of the cart relative to the guided vehicle body. The method for controlling travel speed of the autonomous transport vehicle according to claim 4, wherein the step of controlling the travel speed of the transport vehicle body includes a step of controlling the travel speed of the transport vehicle body so that the transport vehicle body decelerates based on information on the inclination angle of the carriage relative to the transport vehicle body in a horizontal plane. The method for controlling travel speed of the autonomous transport vehicle according to claim 4 or 5, wherein the step of controlling the travel speed of the transport vehicle body includes a step of controlling the travel speed of the transport vehicle body so that the transport vehicle body stops based on information on the inclination angle of the carriage relative to the transport vehicle body in a vertical plane. Further comprising a step of acquiring information on an inclination angle of the transport vehicle body in a vertical plane,
The autonomous guided vehicle driving control method of claim 6, wherein the step of controlling the traveling speed of the guided vehicle body includes a step of controlling the traveling speed of the guided vehicle body so that the guided vehicle body stops based on information on the inclination angle of the carriage relative to the guided vehicle body in a vertical plane and information on the inclination angle of the guided vehicle body in a vertical plane. The method for controlling the travel speed of the autonomous transport vehicle according to any one of claims 1 to 7, wherein the step of controlling the travel speed of the transport vehicle body includes a step of controlling the travel speed of the transport vehicle body taking into account at least one of the shape of the carriage, the weight of the carriage, and the position of the center of gravity of the carriage. The method for controlling travel of an autonomous guided vehicle according to any one of claims 1 to 8, wherein the step of controlling the relative attitude of the carriage to the carrier body in a horizontal plane includes a step of controlling the relative attitude of the carriage to the carrier body in a horizontal plane by driving the coupling part with the driving part when the carrier body turns, so as to cancel out the movement of the carriage due to inertia. The transport vehicle body further includes a stopper that limits movement of the connecting portion,
A driving control method for an autonomous guided vehicle as described in any one of claims 1 to 9, wherein the step of controlling the relative attitude of the cart to the guided vehicle body in a horizontal plane includes a step of controlling the relative attitude of the cart to the guided vehicle body in a horizontal plane by driving the connecting part with the driving part within an angle range limited by the stopper. The step of controlling the traveling speed of the transport vehicle body includes:
acquiring a correction time required to correct a relative attitude of the carriage with respect to the transporting vehicle body by controlling a traveling speed of the transporting vehicle body;
The method for controlling driving of an autonomous guided vehicle according to any one of claims 1 to 10, further comprising: detecting a driving abnormality based on a comparison between the correction time and a reference correction time. The method for controlling travel speed of the autonomous guided vehicle according to claim 11, further comprising the step of learning the reference correction time based on the correction time. The method for controlling travel of an autonomous guided vehicle according to claim 12, wherein the step of learning the reference correction time includes a step of learning the reference correction time for each of the relative attitude of the carriage with respect to the guided vehicle body, the travel speed of the guided vehicle body, the weight of the carriage, or the travel direction of the guided vehicle body. The method for controlling travel of an autonomous guided vehicle according to any one of claims 1 to 13, further comprising a step of moving the guided vehicle body to a coupling position with the cart when the guided vehicle body and the cart are coupled together based on the state of the cart. An autonomous guided vehicle that tows a cart and travels autonomously,
A state acquisition unit that acquires a state of the cart;
a control unit that detects a relative attitude of the carriage with respect to a transport vehicle body based on the state of the carriage acquired by the state acquisition unit, and controls a travel speed of the transport vehicle body based on the relative attitude of the carriage with respect to the transport vehicle body,
The transport vehicle body or the dolly includes a connecting portion that connects the transport vehicle body and the dolly,
The transport vehicle body includes a drive unit that drives the coupling unit,
The control unit, when the cart is towed by the transport vehicle body, controls the relative attitude of the cart to the transport vehicle body in a horizontal plane by driving the coupling part with the drive unit so as to cancel out the movement of the cart due to inertia , in an autonomous transport vehicle. The state acquisition unit is configured to acquire a state of a feature point of the cart,
The autonomous guided vehicle according to claim 15 , wherein the control unit is configured to detect a relative attitude of the cart with respect to the vehicle body based on a state of a feature point of the cart acquired by the state acquisition unit. A trolley and
An autonomous guided vehicle that tows the cart and travels autonomously;
A control device that transmits a command to the autonomous guided vehicle;
The autonomous guided vehicle includes:
A state acquisition unit that acquires a state of the cart;
a transport vehicle control unit that detects a relative attitude of the carriage with respect to a transport vehicle body based on the state of the carriage acquired by the state acquisition unit, and controls a travel speed of the transport vehicle body based on the relative attitude of the carriage with respect to the transport vehicle body,
The transport vehicle body or the dolly includes a connecting portion that connects the transport vehicle body and the dolly,
The transport vehicle body includes a drive unit that drives the coupling unit,
A conveying system in which the conveying vehicle control unit controls the relative attitude of the cart to the conveying vehicle body in a horizontal plane by driving the connecting part with the drive unit when the conveying vehicle body is towing the cart , so as to cancel out the movement of the cart due to inertia .

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