Travel control system for transport vehicle and travel control method for transport vehicle

Abstract

The present disclosure provides a travel control system for a transport vehicle and a travel control method for a transport vehicle, wherein the number of guideline detection sensors of a transport vehicle can be reduced. The present disclosure pertains to a travel control system for a transport vehicle that can move along a real or virtual guideline. The travel control system comprises a control unit, a position / orientation acquisition unit, and a storage unit. The control unit estimates the position of a virtual detection unit (116) relative to the guideline on the basis of information on the position and the orientation of a specific portion of the transport vehicle with respect to the guideline, and information on the position of the virtual detection unit relative to the specific portion and controls the operation of the transport vehicle on the basis of the estimated position of the virtual detection unit relative to the guideline.

Description

Transport vehicle travel control system and transport vehicle travel control method

[0001] The present disclosure relates to a travel control system and a travel control method for a guided vehicle.

[0002] In recent years, automated guided vehicles capable of autonomous travel have been put into practical use for transporting cargo within facilities such as manufacturing factories and warehouses for various products. For example, Patent Literature 1 proposes a technology for a guided vehicle that travels along guidelines.

[0003] Japanese Patent Application Laid-Open No. 2002-297239

[0004] In the technology described in Patent Document 1, sensors are provided on the front and rear of the transport vehicle to detect the guide lines as the transport vehicle travels along the guide lines. However, from the perspective of miniaturizing the transport vehicle, it is desirable to reduce the number of sensors.

[0005] Therefore, the present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide a transport vehicle travel control system and a transport vehicle travel control method that make it possible to reduce the number of guideline detection sensors on the transport vehicle.

[0006] According to the present disclosure, there is provided a travel control system for a transport vehicle capable of moving along a real or virtual guideline, comprising: a control unit that controls the operation of the transport vehicle by controlling a drive unit of the transport vehicle; a position and attitude acquisition unit that acquires relative position information of a specific location on the transport vehicle with respect to the guideline and attitude information of the transport vehicle with respect to the guideline; and a memory unit that stores in advance relative position information of a virtual detection unit set at a location different from the specific location of the transport vehicle with respect to the specific location, wherein the control unit estimates the guideline relative position of the virtual detection unit with respect to the guideline based on the position information and attitude information of the transport vehicle with respect to the guideline and the relative position information of the virtual detection unit with respect to the specific location, and controls the operation of the transport vehicle based on the estimated guideline relative position of the virtual detection unit.

[0007] According to the present disclosure, there is provided a travel control method for controlling the travel of a transport vehicle that can move along a real or virtual guideline by a travel control system, wherein the travel control system comprises: a control unit that controls the operation of the transport vehicle by controlling a drive unit of the transport vehicle; a position and attitude acquisition unit that acquires relative position information of a specific location on the transport vehicle with respect to the guideline and attitude information of the transport vehicle with respect to the guideline; and a memory unit that stores in advance relative position information of a virtual detection unit set at a location different from the specific location of the transport vehicle with respect to the specific location, wherein the control unit estimates the guideline relative position of the virtual detection unit with respect to the guideline based on the position information and attitude information of the transport vehicle with respect to the guideline and the relative position information of the virtual detection unit with respect to the specific location, and controls the operation of the transport vehicle based on the estimated guideline relative position of the virtual detection unit.

[0008] According to the present disclosure, it is possible to provide a travel control system and a travel control method for a guided vehicle that make it possible to reduce the number of guideline detection sensors for the guided vehicle.

[0009] 1 is a plan view showing an example of a guided vehicle and a guideline according to the present embodiment; FIG. 2 is a plan view showing an example of a hardware configuration of a guided vehicle according to the present embodiment; FIG. 3 is a perspective view showing an example of a hardware configuration of a guided vehicle according to the present embodiment; FIG. 4 is a view showing an example of a scene in which a guided vehicle according to the present embodiment retreats along the guideline; FIG. 5 is a view showing another example of a scene in which a guided vehicle according to the present embodiment retreats along the guideline; FIG. 6 is a view showing the positional relationship between a guided vehicle, an object to be transported, and the guideline according to the present embodiment; FIG. 7 is a view showing an example of reverse control so that a guided vehicle and an object to be transported approach the guideline according to the present embodiment; FIG. 8 is a view showing an example of a hardware configuration when a guided vehicle and a towing carriage according to the present embodiment are coupled; FIG. 9 is a view showing another example of a hardware configuration when a guided vehicle and a towing carriage according to the present embodiment are coupled; FIG. 10 is a view showing an example of a configuration of an operating area according to the present embodiment; FIG. 11 is a view showing the positional relationship between a guide line and a guided vehicle when a two-dimensional code constituting the guide line is detected by a guide line detection unit;

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0011] The travel control system of this embodiment is used to control an automated guided vehicle (hereinafter also simply referred to as a "guide vehicle") that is used to transport transported objects such as various manufactured parts and luggage in, for example, a manufacturing factory, a logistics warehouse, etc. Note that this system is not limited to automated guided vehicles, and can also be applied to other manned and unmanned moving bodies.

[0012] The travel control system of this embodiment is a travel control system for a guided vehicle 10 that can move along real or virtual guide lines 111 shown in FIG. 1 . The real guide lines are signs installed on floors, walls, or ceilings, or on signboards rising from these surfaces, to guide the guided vehicle. The real guide lines may be continuous or intermittently arranged. The guide lines may be, for example, multiple two-dimensional codes arranged continuously or intermittently. The virtual guide lines may be virtual two-dimensional or three-dimensional guidelines set on two-dimensional or three-dimensional map data corresponding to real space. In either case, the guide lines are set and arranged so that the guided vehicle can be referred to during operation to guide the vehicle to a predetermined location (destination, waypoint).

[0013] The travel control system of this embodiment includes a control unit that controls the operation of the transport vehicle by controlling a drive unit of the transport vehicle, a position and attitude acquisition unit that acquires current position information of a specific location on the transport vehicle relative to the guideline and attitude information of the transport vehicle relative to the guideline, and a storage unit that stores in advance position information of a virtual detection unit set at a position different from the specific location on the transport vehicle relative to the specific location. The control unit, the position and attitude acquisition unit, and the storage unit are basically implemented on the transport vehicle, but some of them (such as the storage unit) may be implemented on another device that can communicate with the transport vehicle.

[0014] The specific location on the guided vehicle may be, for example, (the center of) the line detection unit 16 on the guided vehicle 10 in FIG. 1 . In this case, the line detection unit 16 is positioned on the guided line 111 so as to overlap with the guided line 111 in a planar view, and therefore the relative distance (difference) with respect to the guided line 111 is zero. Furthermore, if the guided line is configured as a two-dimensional code or the like, the position of the guided line in the extension direction can also be acquired from code information stored in association with the two-dimensional code. Alternatively, the relative position of the guided line (specific location) with respect to the guided line may be estimated by comparing the position information (coordinate information) of the guided line in the map information stored in the storage unit with the current position information (coordinate information) of the guided line estimated based on information acquired from a sensor or a camera.

[0015] The attitude information of the transport vehicle with respect to the guideline can be, for example, the angle θ shown in Figure 1. That is, it can be expressed as the relative angle between the extension direction of the guideline and the front-to-rear direction of the transport vehicle (such as the center line in the width direction). For example, in the case of an image recognition method in which a camera reads a guide line using a two-dimensional code or a barcode, position information is generated based on information about the detected code in addition to a detection signal of the guide line, and further image information about the code is analyzed to generate relative angle information (angle θ) between the guide line and the transport vehicle.

[0016] The control unit estimates the guideline relative position of the virtual detection unit 116 with respect to the guideline 111 based on the position information and posture information of the guideline and the relative position information of the virtual detection unit with respect to a specific location of the guideline. Then, the control unit controls the operation of the guideline based on the estimated guideline relative position of the virtual detection unit. With this configuration, the guideline can be virtually detected and controlled to follow the guideline even in a position where a sensor for detecting the guideline is not actually provided. As a result, the number of guideline detection sensors of the guideline detection unit can be reduced.

[0017] The relative position information of the virtual detection unit 116 with respect to the specific location on the transport vehicle may be set as a position L1 rearward from the center of the line detection unit 16 of the transport vehicle 10 (in the direction toward the rear along the center line of the transport vehicle in the width direction), as shown in FIG. 2 . Alternatively, it may be set as a distance L2 from the turning center 18 of the transport vehicle, or as a specific coordinate (x1, y1) in a two-dimensional coordinate system (planar coordinate system) with the turning center 18 as the origin. The virtual detection unit 116 is preferably located rearward of the pair of left and right drive wheels, but may also be located forward or at any other position. The virtual detection unit 116 may be located at the same position as the turning center 18 or the center of the transport vehicle. Note that in this example, the center point of the line detection unit 16 is set as the specific location, but it can be set at any position different from the virtual detection unit 116. At least the specific location is set at a position where the control unit can acquire its position information and attitude information.

[0018] The guideline position of the virtual detection unit relative to the guideline can be estimated by calculating the distance D from the guideline to the virtual detection unit 116, for example, using the distance L1 from the line detection unit 16 shown in FIG. 1 to the virtual detection unit 116 and the relative angle θ. The calculation formula can be D = L1 * sin θ. Furthermore, it can be estimated from the posture information relative to the guideline on which side of the guideline the virtual detection unit 116 is located (for example, on the left or right side of the guideline, based on the left-right direction of the transport vehicle).

[0019] In the case of Fig. 1, for example, the control unit controls the drive unit of the guided vehicle so that the virtual detection unit 116 moves onto the guideline. Specifically, the vehicle may be caused to turn until the relative angle θ becomes 0° at that position or until the virtual detection unit 116 is located on the guideline, or the vehicle may first move forward so that the turning center 18 of the guided vehicle is located on the guideline and then move forward until the relative angle θ becomes 0°, or the vehicle may move backward while slowly turning until the virtual detection unit 116 is located on the guideline. When the vehicle moves forward so that the turning center 18 of the guided vehicle is located on the guideline, the control unit can calculate the forward distance as the difference between L1 and L2 shown in Fig. 2.

[0020] Here, when the line detection unit 16 detects a guideline, the relative position and orientation of the line detection unit 16 with respect to the guideline can be acquired, and therefore the relative position of the virtual detection unit 116 with respect to the guideline can be estimated based on the relative position and orientation of the line detection unit 16 with respect to the guideline and the relative position of the virtual detection unit 116 with respect to the line detection unit 16 stored in the memory unit.

[0021] Furthermore, when the line detection unit 16 does not detect the guideline (when the line detection unit 16 is not located on the guideline), the position of the specific point of the transport vehicle relative to the guideline can be estimated by comparing the guideline position information included in the map data stored in the storage unit with the estimated self-position information (the position of the specific point of the transport vehicle), and the relative position of the virtual detection unit 116 with respect to the guideline can be estimated based on the position information of the virtual detection unit 116 with respect to the specific point stored in the storage unit. By repeating this estimation process and controlling the drive unit of the transport vehicle to turn, move forward, move backward, etc., the virtual detection unit can be brought closer to the guideline, and the virtual detection unit can be moved along the guideline.

[0022] When estimating the guideline position of the virtual detection unit relative to the guideline, the control unit may acquire a relative difference between the position of the guideline and the position of the virtual detection unit. The difference may be the above-mentioned distance D. Alternatively, the control unit may estimate the angle of the travel direction (front-rear direction) of the transport vehicle relative to the extension direction of the guideline as the difference.

[0023] The transport vehicle may include a guide detection unit that is disposed at a specific location and detects an actual guideline, and the position and orientation acquisition unit may estimate relative position information of the specific location on the transport vehicle with respect to the current guideline and orientation information of the transport vehicle with respect to the guideline based on the detection information of the guide detection unit. The guide detection unit may be the line detection unit 16.

[0024] The storage unit may store in advance map data (map data) corresponding to the real space and position data of virtual guidelines set on the map data. The position and orientation acquisition unit may estimate relative position information of a specific location on the transport vehicle with respect to the current guideline and orientation information of the transport vehicle with respect to the guideline based on the position data of the virtual guideline on the map data and current position information and orientation information of the transport vehicle. The current position information and orientation information of a specific location on the transport vehicle (e.g., the center of the transport vehicle or the position of a position sensor) can be acquired, for example, by a position estimation unit 265 and an orientation detection unit 235 (described later). The map data and the position information of the guideline may be stored in advance in the storage unit or may be generated based on sensor data acquired while the transport vehicle is traveling. In this case, for example, SLAM (Simultaneous Localization and Mapping) technology using sensor data such as LiDAR may be employed.

[0025] The virtual detection unit 116 may be set at a position behind the specific location on the transport vehicle. For example, the virtual detection unit 116 is located behind the specific location, which may be the line detection unit 16, the turning center 18, or the center of the transport vehicle. The specific location may be located either in front of or behind the pair of left and right drive wheels.

[0026] When the transport vehicle retreats, the control unit may determine whether the virtual detection unit is located on a guideline, and if the virtual detection unit is located on a guideline, control the operation of the transport vehicle so that the virtual detection unit moves along the guideline, and if the virtual detection unit is not located on a guideline, control the operation of the transport vehicle so that the virtual detection unit approaches the guideline.

[0027] The drive unit may have a pair of left and right drive wheels. When the drive unit is configured with a pair of left and right drive wheels that can be controlled individually, the vehicle can turn so that the midpoint between the left and right drive wheels is the turning center. The drive unit may have other configurations.

[0028] The control unit may estimate the position of the virtual detection unit relative to the guideline at predetermined intervals. The predetermined interval may be set to any value, such as 0.1 seconds, 1 second, or 5 seconds. Alternatively, the control unit may repeatedly estimate the position of the virtual detection unit relative to the guideline based on other conditions rather than the predetermined interval. The other conditions may be conditions based on the distance or speed of movement, such as movement by a predetermined distance or a change in speed. By having the guided vehicle repeatedly check its position relative to the guideline, the accuracy of movement can be improved.

[0029] The current position of the transport vehicle may be acquired by scanning a two-dimensional code as a guideline installed on the road surface, wall surface, or ceiling surface. The use of a two-dimensional code such as an AR marker can improve the estimation accuracy.

[0030] <Configuration of the Transport Vehicle> FIG. 3 is a perspective view showing an example of the hardware configuration of a transport vehicle according to this embodiment. The transport vehicle in this example is an unmanned transport vehicle, but the present invention can also be applied to various vehicles that people can ride in. Arrow 15 in FIG. 3 indicates the traveling direction (forward) of the transport vehicle. The traveling direction is basically the forward direction of the transport vehicle, but can also be the rear depending on the situation. As shown in FIG. 3, the transport vehicle includes a coupling unit 11 for switching between a coupled and uncoupled state with the carriage, an object position detection unit 12 for detecting objects around the transport vehicle, drive wheels 13, and non-drive wheels 14.

[0031] For example, a connecting unit 11 and an object position detection unit 12 are mounted on the top surface of the transport vehicle. The connecting unit 11 is configured, for example, by an actuator. When connecting to a carriage, the actuator extends upward to connect to a connecting portion (not shown) on the carriage, and when disconnecting, the actuator retracts to disconnect the connecting unit from the connecting portion on the carriage. The connecting units 11 are arranged at four positions surrounding the drive wheels 13 of the transport vehicle on a plane, allowing connection to the carriage at five positions. In this embodiment, an example having four connecting units is described, but the number of connecting units does not necessarily have to be five, and any number greater than one can be selected. The connecting structure between the transport vehicle and the transported object is not particularly limited, and any connecting structure can be adopted.

[0032] The object position detection unit 12 is a device that detects the distance from the transport vehicle to an object. Examples of the object position detection unit 12 include a laser distance sensor (such as LiDAR (Light detection and ranging)) that measures the distance and direction to an object by emitting laser light and measuring the time it takes for the light to hit the object and bounce back; a millimeter-wave radar that detects the distance to an object based on a millimeter-wave transmission signal and a received signal that is reflected off the object; and a camera-type distance sensor that measures the distance to an object by photographing the object with a camera and analyzing the photographed image. In this embodiment, the object position detection unit 12 is disposed on the top surface of the transport vehicle at the front in the traveling direction. However, instead, the object position detection unit 12 may be disposed on the front side in the traveling direction. Furthermore, the object position detection unit 12 may be disposed not only at the front but also at the rear side or both left and right sides in the traveling direction.

[0033] The object position detection unit 12 can detect the position and posture (relative position and angle with respect to the transport vehicle) of an object to be transported, such as a dolly connected to the transport vehicle. The object position detection unit 12 may be provided at the front and rear of the vehicle body, and the front side may detect obstacles and people, and the rear side may detect objects to be transported, or vice versa.

[0034] The object position detection unit 12 may be configured to detect objects in a 360-degree range around the transport vehicle, but is configured to detect objects at least in the traveling direction 15 of the transport vehicle. The traveling direction 15 may be either in front of or behind the transport vehicle.

[0035] FIG. 2 is a bottom view showing an example of the hardware configuration of a transport vehicle according to this embodiment. Drive wheels 13 are provided on the bottom of the transport vehicle at both the left and right sides in the direction of travel 15 of the transport vehicle, and non-drive wheels 14 are provided in front of and behind each drive wheel 13. The drive wheels 13 are connected to the rotating shaft of a motor and driven, and the right drive wheel and the left drive wheel are controlled individually. The control unit can control the speed of the transport vehicle by controlling the rotation speed of the drive wheels. The control unit can also individually control the rotation speed and rotation direction of each drive wheel to make the transport vehicle curve, turn the transport vehicle on the spot to change direction, stop the transport vehicle, and move backward. The non-drive wheels 14 are not driven and rotate passively as the transport vehicle moves due to the drive wheels 13. The non-drive wheels 14 have, for example, forks that secure the wheels and axles, and the forks are formed by swivel casters that are rotatably connected to the bottom member of the transport vehicle. Therefore, the wheel rotation direction of the non-driven wheels 14 changes passively depending on the traveling direction and rotational movement of the transport vehicle. Although Fig. 2 illustrates a hardware configuration of a transport vehicle having two driven wheels and four non-driven wheels at the four corners, the present invention is not limited to this hardware configuration, and it is also possible to adopt a configuration with a total of four wheels, two driven wheels and two non-driven wheels, and it is also possible to adopt a configuration in which the front wheels are steerable in such a four-wheel configuration.

[0036] A guide line detector 16 for detecting guide lines (guidelines) is provided on the bottom of the transport vehicle. The guide line detector 16 is preferably located further forward in the direction of travel than the drive wheels 13. This allows the transport vehicle to easily follow the guide lines when traveling around curved areas. Furthermore, by quickly receiving information from the guide lines as the transport vehicle and the towing cart advance, they can quickly take action, such as stopping. The guide line detector uses a sensor appropriate for the type of guidance method, as described above. A pickup coil is used when using an electromagnetic induction method; a magnetic sensor is used when using a magnetic induction method; and a camera is used when using an image recognition method. The guide lines may be provided on the side walls or ceilings of buildings, rather than on floors. The transport vehicle's sensors (including cameras) can be installed in locations where the guidelines can be recognized (such as the bottom, side, or top of the transport vehicle). The guidelines may also be virtual tracks created on two-dimensional or three-dimensional map data. The control unit of the transport vehicle may control the travel of the transport vehicle along virtual guidelines based on map information and trajectory information (travel route information) stored in advance in the memory unit, and current self-position information estimated based on information from cameras, sensors, etc.

[0037] In this embodiment, a virtual detection unit 116 is set at a predetermined location on the transport vehicle. As virtually shown in FIG. 2 , the virtual detection unit 116 is set at a location different from the line detection unit 16, which is located at a specific location on the transport vehicle. The virtual detection unit 116 is preferably located on the opposite side of the guide line detection unit 16 from the center (or turning center) of the transport vehicle (for example, symmetrical with respect to the center line of the transport vehicle, such as a line symmetry with respect to the center point, or a point symmetry with respect to the center point). For example, if the guide line detection unit 16 is located forward of the center of the transport vehicle, the virtual detection unit can be set at the rear of the transport vehicle, or vice versa. This allows for effective travel control by utilizing the virtual detection unit 116 set at a location where no line detection unit 16 is provided. If the guide line detection unit 16 is located at the rear of the transport vehicle, the virtual detection unit can be set at the front of the transport vehicle. The guide line detection unit 16 or virtual detection unit may be located at the turning center of the transport vehicle. The number of virtual detection units is not limited to one, and multiple virtual detection units may be set. The virtual detection unit can be set at any position, for example, at any or all of the four corners of the transport vehicle (front right, front left, rear right, rear left). Information about the position of the virtual detection unit is pre-stored in a storage unit. The position information can be relative position information with respect to a specific location, such as the center of the transport vehicle, the turning center, or the center of the line detection unit 16. The position of the line detection unit may be set using three-dimensional coordinates. As shown in FIG. 2 , the center point (midpoint) between the left and right drive wheels 13 is the turning center 18. In this example, the turning center coincides with the center of the transport vehicle, but may be offset from the center of the transport vehicle. Information about the relative positional relationships between the turning center 18, the center of the transport vehicle, and the virtual detection unit 116, such as the distance L2 from the turning center 18 to the virtual detection unit 116 and the distance L3 from the center of the transport vehicle to the virtual detection unit 116, is also pre-stored in a storage unit.

[0038] Here, as shown in Figures 4 and 5, there are situations in which the transport vehicle retreats along the guidelines depending on the purpose. For example, in the case of Figure 4, after towing an object to be transported along the guidelines to a stopping position, if it is necessary to move the object to the opposite side, the coupling may be temporarily released, and the transport vehicle alone may move to the opposite side of the object, and the object may be recoupled. In this case, when recoupling the object, the transport vehicle retreats along the guidelines toward the object. Figure 5 shows an example in which the transport vehicle to which the object is coupled retreats along the guidelines, stopping the object at a predetermined position.

[0039] In either case, the drive unit is controlled so that the virtual detection unit 116 is positioned on the guideline while repeatedly estimating the relative position and angle of the virtual detection unit 116 with respect to the guideline, thereby allowing the transport vehicle to move backward in the intended direction (the direction along the guideline). As a result, for example, smooth connection of transported objects becomes possible and the possibility of collision with obstacles on the left and right located behind can be reduced. Note that the drive unit can be controlled so that the virtual detection unit 116 is positioned on the guideline not only when moving backward, but also when moving forward and left and right.

[0040] The virtual detection unit may be set at a predetermined position on the object to be transported that is connected to the transport vehicle, and the control unit may estimate the position of the virtual detection unit based on relative position information and posture information of the object to be transported with respect to the transport vehicle.

[0041] 6 and 7, when a transport vehicle transports an object coupled to the transport vehicle, a virtual detection unit may be set at any position, such as the rear of the object (the side farther from the transport vehicle). When the transport vehicle and the object are fixed so that they cannot swing, the relative positions of the transport vehicle and the object do not change, and therefore control similar to that when virtual detection unit 116 is set on the transport vehicle is possible. On the other hand, when the relative positional relationship of the object to the transport vehicle changes, such as when the object is coupled to the transport vehicle so that it can swing (rotate) around a vertical shaft as a fulcrum, it is preferable to detect the relative position of the object with respect to the transport vehicle using an angle sensor or the like.

[0042] Specifically, an encoder attached to the shaft of the transport vehicle may measure the displacement angle from a predetermined state, or a distance sensor attached to the transport vehicle may measure the distance from the transport vehicle to specific points on the left and right sides of the transported object to estimate the relative angle. As shown in FIG. 6 , the relative position of the virtual detection unit with respect to the specific point can be estimated using the distance L4 from the specific point on the transport vehicle to axis A (the axis of the swing shaft attached to the connection between the transport vehicle and the transported object), the distance L5 from axis A to the virtual detection unit, and the angle α. The relative position (distance D) of the virtual detection unit with respect to the guideline can then be calculated based on the relative position and orientation of the specific point with respect to the guideline and the relative position and orientation of the virtual detection unit with respect to the specific point. This allows the transport vehicle to be controlled so that the virtual detection unit moves along the guideline by setting a virtual detection unit on the transported object rotatably connected to the transport vehicle. In this case, the guided vehicle may be advanced until the virtual detection unit is positioned on the guideline, and then retreat from a state in which the virtual detection unit is positioned on the guideline, the widthwise center lines of the guided vehicle and the object to be transported are parallel to the extending direction of the guideline, and the relative angle α of the object to be transported with respect to the guided vehicle is 0. Note that, for example, if the line detection unit 16 of the guided vehicle is positioned on the guideline and the guided vehicle is advanced straight along the guideline, the towed object to be transported will also be aligned on the guideline, and the guided vehicle may be retreated after that. Alternatively, as shown in Figure 7, the guided vehicle may be retreated while making a gentle curve, and the turning control may be performed while retreating so that the virtual detection unit and line detection unit are positioned on the guideline.

[0043] The transport vehicle may be provided with an object detection unit that detects the posture (e.g., the relative angle α) of the object to be transported. The object detection unit may be, for example, an encoder, a distance measurement sensor, a resolver, or the like.

[0044] The control unit may select and set one of a plurality of predetermined positions of the virtual detection unit based on whether or not the transported objects are connected. For example, the control unit may set the virtual detection unit at the rear of the transport vehicle shown in Fig. 2 when the transported objects are not connected, and set the virtual detection unit at the rear of the transported objects shown in Fig. 6 when the transported objects are connected. The control unit can determine whether or not the transported objects are connected based on information from a sensor provided on the transport vehicle, etc.

[0045] 8 shows an example of the hardware configuration when a transport vehicle and a towing dolly according to this embodiment are coupled together, specifically showing an example in which the transport vehicle 10 is coupled to the dolly while sliding underneath the dolly to be towed. In this case, a cone-shaped coupling receptacle is disposed on the bottom of the dolly at a position corresponding to the conical coupling part 11, and the dolly can be coupled by extending the coupling part 11 upward, and can be released from the dolly by retracting the coupling part 11. The transport vehicle 10 may be coupled to the front, center, or rear of the dolly.

[0046] FIG. 9 shows another example of a hardware configuration when a transport vehicle and a towing dolly according to this embodiment are coupled. The transport object, such as the towing dolly, may be coupled to the transport vehicle so that it can swing (rotate) around an axle as a fulcrum, or may be fixed so that it cannot swing relative to the transporter. In the example shown in FIG. 9 , the transport vehicle is coupled to the dolly while positioned next to the dolly 2000 (not directly below the dolly, but offset forward, backward, left, or right). The dolly has a coupling receiving portion 2010 that couples with at least a portion of the coupling portion 11 of the transport vehicle. The coupling portion 11 can be coupled to the dolly by extending the coupling portion 11 upward, and can be released from the dolly by retracting the coupling portion 11. While FIGS. 8 and 9 show an example in which the coupling portion 11, which is formed by an actuator or the like and located on the top surface of the transport vehicle, is extended or retracted in the vertical direction to couple and release the coupling from the dolly, the coupling method between the transport vehicle and the dolly is not limited to this, and other coupling methods may be used. Furthermore, the transported object coupled to the transport vehicle is not limited to a cart, but may be, for example, a pallet or cabinet without wheels, a conveyor, a robot arm, etc. When transporting a pallet or cabinet, the transport vehicle slides under the pallet or cabinet and couples to the pallet or cabinet in a lifted state.

[0047] FIG. 10 is a diagram showing an example of the configuration of an operation area 130 according to this embodiment. As shown in FIG. 10 , guide lines 131 (guidelines) are laid within the operation area 130. When a guided vehicle traveling in autonomous travel mode detects the guide lines 131 at a preset travel mode switching position 132, the travel control mode is switched from the autonomous travel mode to the guided travel mode. Conversely, when a guided vehicle traveling in guided travel mode on the guide lines enters the preset travel mode switching position 132, the travel control mode is switched from the guided travel mode to the autonomous travel mode. In order to guide the guided vehicle to a position close to a shelf where packages are stored, a conveyor belt, or a worker's work position, the track formed by the guide lines 131 is laid at a position close to the shelf or work position via multiple branch points.

[0048] A guided vehicle 10 traveling in an autonomous travel area where no guide lines are installed in autonomous travel mode changes its travel mode to a guided travel mode in which it follows the guide lines when it enters travel mode switching position 132 and detects a guide line 131. On the other hand, when a guided vehicle traveling in guided travel mode on a guide line enters travel mode switching position 132, the travel control mode is switched from the guided travel mode to the autonomous travel mode, and the guided vehicle leaves the guide line and starts autonomous travel.

[0049] 10 can be applied to various conventionally used induction lines as described below. Specifically, for example, an electromagnetic induction method in which a pickup coil on the transport vehicle detects a magnetic field generated by passing a weak AC current through a metal wire installed as the induction line, a magnetic induction method in which a magnetic sensor on the transport vehicle reads a magnetic tape laid on the floor as the induction line, or an image recognition method in which a camera on the transport vehicle takes an image of a code (such as a barcode or a two-dimensional code) laid on the floor as the induction line and processes the image.

[0050] 11 shows the positional relationship between the guide line and the transport vehicle when the two-dimensional code that constitutes the guide line is detected by the guide line detection unit 16. The guide line is formed by printing a plurality of two-dimensional codes, each with code information printed on a two-dimensional plane, aligned in the direction of the guide line, as shown in two-dimensional code 1000. When the guide line detection unit 16 detects a two-dimensional code, it acquires the position information of the two-dimensional code based on the code information acquired from the two-dimensional code.

[0051] FIG. 12 shows the positional relationship between the guide line and the transport vehicle when the guide line detection unit 16 detects the magnetic tape that constitutes the guide line. The guide line detection unit 16 shown in FIG. 12 is configured with multiple magnetic sensors 17 that detect the magnetic tape, arranged laterally in the direction of travel of the transport vehicle. Each of the multiple magnetic sensors 17 provided in the guide line detection unit 16 outputs a detection signal indicating whether or not the magnetic tape has been detected. In the example shown in FIG. 12, three magnetic sensors 17A located in the center of the guide line detection unit 16 detect the magnetic tape, while two magnetic sensors 17B on each side of the guide line detection unit 16 do not detect the magnetic tape. This makes it possible to detect where the guide line is located (to the right, left, center, etc.) within the range of the guide line detection unit 16 (the entire area including the multiple magnetic sensors).

[0052] 13, in the virtual detection unit 116, a plurality of virtual sensors may be set, similar to the magnetic sensor 17, and the position information of the virtual sensors may be set in the storage unit, so that the position of each virtual sensor relative to the guideline may be estimated. In this case, the accuracy of the position estimation relative to the guideline using the virtual detection unit can be improved.

[0053] <Configuration of the Transport System> Next, the configuration of the transport system of this embodiment will be described. FIG. 14 is a diagram showing an example of the overall configuration of the transport system according to this embodiment. The transport system 1000 includes multiple transport vehicles (10a, 10b), a dolly 2000 as the transported object, a control device 3000 capable of displaying the status of the transport vehicles or inputting commands to the transport vehicles, a general control device 4000 that manages information necessary for the operation of the transport vehicles, an input / output device 5000 that displays information from the general control device and inputs information to the general control device, and a communication network 6000 that communicatively connects the multiple transport vehicles (10a, 10b), the control device 3000, and the general control device 4000. The various devices, such as the control device 3000, the general control device 4000, and the input / output device 5000, may be separate devices, or may be formed in part or in whole as an integrated device.

[0054] The transport system 1000 can also be connected to an external system 7000 via a communication network 6000. When the transport system 1000 is introduced into a manufacturing factory to transport parts required for manufacturing from a storage warehouse to a manufacturing line, the transport system 1000 performs inter-system cooperation with a manufacturing management system as the external system 7000. In this case, by obtaining information on the operational progress of manufacturing work from the manufacturing management system, the transport volume and transport route of the transport vehicle can be dynamically adjusted according to the progress of the manufacturing work.

[0055] As another example, when the conveyance system 1000 is introduced into a logistics warehouse, and when cargo is brought into the warehouse by truck or the like, the incoming cargo is transported from an inlet to a storage warehouse, and when cargo is shipped from the warehouse, the cargo to be shipped from the storage warehouse is transported to an outlet, the conveyance system 1000 performs inter-system cooperation with a logistics management system as an external system 7000. In this case, by obtaining information related to carrying in and shipping from the logistics management system, the transportation volume and transportation route by the transport vehicle can be changed.

[0056] In a facility where a transport system is installed, a plurality of transport vehicles (10a, 10b) are generally in operation, and each transport vehicle is communicably connected to other transport vehicles and other components via a communication network 6000. For example, the transport vehicle transmits various detection information detected by its own detection unit and other control information to the control device 3000, the overall control device 4000, and other transport vehicles 10. The transport vehicle 10 is also electrically connected to the cart 2000 or communicably connected via short-range communication means, and is configured to be able to receive information about the connection state and cart identification information from the cart.

[0057] The controller 3000 has a function to display status information of each transport vehicle and a function to input commands to a specified transport vehicle. For example, the status information of the transport vehicle displayed on the controller includes the identification information, position (coordinates, position on a map), speed, direction, driving history, charge level information of the battery mounted on the transport vehicle and serving as the power source for the transport vehicle, and identification information of the transported object such as a cart transported by the transport vehicle. Examples of commands input to the transport vehicle include command information regarding the destination (destination position) of the transport vehicle, operation commands to couple or uncouple from the cart, a command to start the transport vehicle, a command to stop the transport vehicle, and a command to return to the charging station.

[0058] 15 shows a configuration diagram of the overall control device 4000 in this embodiment. The overall control device 4000 has a status information recording unit 4010 that records status information of multiple guided vehicles operating in a facility area, an operation scenario management unit 4020 that manages operation scenarios of the multiple guided vehicles, a map management unit 4030 that generates and updates a map of the work area based on detection information of the guided vehicles including detection information of guide lines acquired by a guide line detection unit of the guided vehicles, an abnormality determination unit 4040 that determines abnormalities in the guide lines and the guided vehicles based on the detection information of the guided vehicles, and a communication unit 4050 that communicates with an external input / output device 5000 and a communication network 6000.

[0059] The status information of the guided vehicles recorded by the status information recording unit 4010 includes, for example, obstacle detection positions detected by the multiple guided vehicles during operation, guide line detection positions, history information of the travel positions of the guided vehicles, information on the battery charge level, identification information of the carriages connected to the multiple guided vehicles, operation modes of the multiple guided vehicles (guided travel mode, autonomous travel mode, virtual sensor use mode), various other detection information detected by the detection unit 230 of the guided vehicles, map information of the work area, etc. The operation scenario managed by the operation scenario management unit 4020 includes, for example, information on the destinations of the multiple guided vehicles, the content of multiple operations to be performed until the vehicles reach the destination, the operation sequence of the multiple operations, and switching conditions for the multiple operations.

[0060] The map management unit 4030 generates a map including the position information of obstacles and guide lines within the work area based on the historical information of the obstacle detection positions, guide line detection positions, and travel position of the guided vehicle detected by the guided vehicle. Furthermore, the map management unit 4030 updates the information of the guide lines and work area registered in the map based on the information of the detected positions of the guide lines accumulated by one or more guided vehicles.

[0061] The abnormality determination unit 4040 determines abnormalities in the guide lines and the guided vehicle based on the position information of the guide lines registered in the map information and the detection information of the guided vehicle including the detected position information of the guide lines detected by the guided vehicle.

[0062] The input / output device 5000 displays information recorded in the status information recording unit 4010 of the overall control device 4000, map information (including map update information), and the results of judgment by the abnormality judgment unit, and can add or update new operation scenarios by inputting operation scenarios managed by the operation scenario management unit 4020. Information input to the input / output device 5000 includes, for example, that the destination of a given transport vehicle is the working area A of the guided travel area 110, the operation content for entering the guided travel area 110 and arriving at the working area A, operation switching conditions, etc.

[0063] <Functions of the Transport Vehicle> The functions of the transport vehicle will be described using Figure 16. Figure 16 is a diagram showing the functional configuration of the transport vehicle according to this embodiment. The transport vehicle 10 is equipped with a communication unit 210 that communicates with a carriage 2000 outside the transport vehicle and a communication network 6000, a recording unit 220 (including a memory unit), a detection unit 230 equipped with various sensors described below, a coupling unit 11 for coupling with the carriage, a wheel drive unit 280 that drives the wheels, an input unit 240, a display unit 250, a control unit 260 that controls the operation of the wheel drive unit 280, etc.

[0064] The recording unit 220 has a function of recording information received from the outside by the communication unit 210, detection information detected by the detection unit 230, and information generated and output by the control unit. The recording unit 220 stores a specific location of the transport vehicle, position information of the virtual detection unit, information of the virtual detection unit according to the type of transport object to be connected, etc. The recording unit 220 can store information such as the destination position of the transport vehicle, movement route, movement history, etc. The recording unit 220 can store speed information according to the distance to the destination position, calculation formula (program) information for calculating the speed information, etc.

[0065] The detection unit 230 includes an object position detection unit 12, a guide line detection unit 16, a travel distance detection unit 233, a collision detection unit 234, a posture detection unit 235, and a charge amount detection unit 236. As described above, the object position detection unit 12 includes a laser distance sensor (such as LiDAR (Light detection and ranging)) that measures the distance and direction to an object by emitting laser light and measuring the time it takes for the light to hit the object and bounce back; a millimeter-wave radar that detects the distance to an object based on a millimeter-wave transmission signal and a received signal that is reflected by the object and returns; or a camera-type distance sensor that measures the distance to an object by photographing the object with a camera and analyzing the captured image. The control unit can estimate information about the current position and current speed of the transport vehicle based on information from the detection unit. The detection unit 230 includes a position sensor, such as a GNSS, that detects the current position of the transport vehicle, and a speed sensor that detects the speed of the transport vehicle.

[0066] As described above, the guide line detection unit 16 uses a sensor according to the type of guidance method. When the electromagnetic induction method is used, a pickup coil is used as the guide line detection unit sensor; when the magnetic induction method is used, a magnetic sensor is used; and when the image recognition method is used, a camera is used. The guide line detection unit detects the guide line when it is located directly above the guide line and outputs a detection signal. Furthermore, when the image recognition method is used, in which a camera reads a guide line using a two-dimensional code or barcode, position information is generated based on the information of the detected code in addition to the guide line detection signal, and further, by examining the image information of the code, relative angle information (angle θ) between the guide line and the transport vehicle can be generated.

[0067] The travel distance detection unit 233 detects the number of rotations of the non-driven wheels 14 or the driven wheels 13, and can measure the travel distance and travel speed of the transport vehicle based on the detected information on the number of rotations and information on the diameter (or circumference) of the non-driven wheels or the driven wheels (in this case, the travel distance detection unit 233 can function as a speed sensor). Alternatively, a millimeter-wave sensor that irradiates millimeter waves in any horizontal direction (including a wall or floor) and detects reflected waves can be used to detect the travel speed of the transport vehicle and integrate the travel speed to estimate the travel distance. Any method for measuring the travel distance or acquiring the travel speed other than the above-mentioned methods can also be applied.

[0068] The collision detection unit 234 has the function of detecting when the transport vehicle collides with an object or a person. Specifically, it can detect acceleration using a gyro sensor or the like and determine that a collision has occurred when a sudden change in acceleration is detected. As an alternative, it is possible to install a physical switch along with a bumper at the front of the transport vehicle in the direction of travel and determine that a collision has occurred when the physical switch is pressed. Collision detection methods other than those described above can also be applied. When the collision detection unit 234 detects a collision, it stops the transport vehicle and records at least one of information on the collision occurrence and the collision location in a recording unit, and notifies the information to the overall control device 4000 and the control device 3000. The attitude detection unit 235 detects the direction (attitude) of the host vehicle based on a magnetic compass, information on the rotation speed of the left and right drive wheels, or wheel steering information.

[0069] The charge amount detection unit 236 detects the charge amount of the battery that is the power source for the transport vehicle. When the charge amount detected by the charge amount detection unit 236 falls below a predetermined value, the unit determines that charging is necessary, records the detection information of the decrease in charge amount in the recording unit, and notifies the information to the overall control device 4000 and the control device 3000. Furthermore, when it is detected that the charge amount is below a predetermined value, in addition to the above processing, the unit may automatically move to a charging spot and charge the vehicle. Note that the predetermined value used by the charge amount detection unit 236 to determine that charging is necessary may be a value set in advance based on at least one of the distance to the destination set for the transport vehicle and the weight of the transported object coupled to the transport vehicle.

[0070] The input unit 240 is configured with a physical switch or a touch panel mounted on the transport vehicle, and allows a user to directly input operation commands, etc. to the transport vehicle. The display unit 250 is configured with, for example, a liquid crystal panel mounted on the transport vehicle, and can display status information of the transport vehicle (various types of detection information by the detection unit 230, the type of driving mode, the operation scenario currently being executed, etc.).

[0071] The control unit 260 includes an operation determination unit 261, a mode switching unit 262, a connection control unit 263, a display control unit 264, a position estimation unit 265, and a travel control unit 266. The operation determination unit 261 determines the operation of the guided vehicle based on the operation scenario of the self-guided vehicle acquired from the operation scenario management unit 4020.

[0072] The mode switching unit 262 switches the travel mode of the transport vehicle between a guided travel mode and an autonomous travel mode based on conditions predetermined by an operation scenario or the like or commands input by the input unit 240. The connection control unit 263 controls the operation of the connection unit 11 to control connection / disconnection with a transported object such as a cart based on conditions predetermined by an operation scenario or the like or commands input by the input unit 240. The display control unit 264 controls the input IF of the input unit 240 and the display unit 250 described above.

[0073] The position estimation unit 265 can estimate the position and attitude of the vehicle at a given time, including the current position and current attitude, within the entire travel area, based on the travel distance detected by the travel distance detection unit 233, the orientation information of the vehicle detected by the attitude detection unit 235, and map information of the entire area recorded in the recording unit 220. Alternatively, the position and attitude of the vehicle within the entire travel area can be estimated based on information on the distance and direction from the vehicle to an object measured by the object position detection unit 12 and map information of the entire area recorded in the recording unit 220. If the map information includes guidelines, the position and attitude relative to the guidelines can also be estimated. Alternatively, if the vehicle is traveling on a guide line formed by a two-dimensional code, the position and attitude of the vehicle within the entire travel area can be estimated based on the identification information of the two-dimensional code and the map information. The position estimation unit 265 can also acquire position information using a GNSS or the like provided in the transport vehicle.

[0074] The position estimation unit 265 can estimate the position of an object based on the estimated vehicle position information and the distance information from the vehicle to the object detected by the object position detection unit 12. It is also possible to estimate the installation position and extension angle of the guide line based on the vehicle position information and attitude information when the guide line detection unit 16 detects the guide line.

[0075] The travel control unit 266 controls the travel of the transport vehicle based on at least one of the determination information by the operation determination unit 261 and the mode switching unit 262. The travel control unit 266 can control the forward movement, backward movement, stopping, turning, and the moving speed and turning speed of the transport vehicle. Specifically, the travel control unit 266 individually controls the right wheel drive unit 281 and the left wheel drive unit 282 of the wheel drive unit 280. The right wheel drive unit 281 and the left wheel drive unit 282 are configured with, for example, motors, and by individually controlling the rotation speed and rotation direction of each drive wheel, it becomes possible to make the transport vehicle travel on a curve with an arbitrary trajectory radius or to turn the transport vehicle on the spot to change direction.

[0076] For example, when the transport vehicle moves along the guideline, the control unit 260 can execute a travel control process to control the travel speed of the transport vehicle based on the difference in distance between the current position of the transport vehicle and the destination position in the extension direction of the guideline. The control unit 260 may also execute a distance estimation process to calculate the difference in distance between the current position of the transport vehicle and the destination position in the extension direction of the guideline based on the current position information and the destination position information of the transport vehicle.

[0077] The distance estimation process can estimate the distance difference between the current position of the transport vehicle and the destination position in the extension direction of the guideline by calculating the difference between the position coordinates as the current position information of the transport vehicle and the position coordinates of the destination position as the destination position information, for example.

[0078] When the transport vehicle advances toward the destination position, a travel control process may be executed based on the distance to the destination position, and when the transport vehicle passes the destination position, a travel control process may be executed to control the speed in the backward direction based on the distance in the same way as when the transport vehicle advances. In this case, even if the transport vehicle passes the destination position, the transport vehicle can reach the destination position while retreating with high accuracy and efficiency in the same way as when the transport vehicle advances.

[0079] The control unit 260 may perform an angle estimation process to estimate the angle of the guideline relative to the extension direction of the guideline based on information from a sensor installed on the guideline, a relative position estimation process to estimate the relative position of a specific point on the guideline and the guideline in a direction perpendicular to the extension direction of the guideline based on information from a sensor installed on the guideline, and control the orientation of the guideline based on the angle and relative position of the guideline. For example, in the case of an image recognition method in which a camera reads a guideline using a two-dimensional code or barcode, position information may be generated based on information from the detected code in addition to a guideline detection signal, and relative angle information between the guideline and the guideline may be generated by further analyzing image information from the code. The control unit 260 controls the travel of the guideline so that the angle (orientation) of the guideline ultimately matches the extension direction of the guideline (or the angle difference is within a predetermined value (e.g., 1°, 3°, 5°, etc.) or less) and so that the deviation between the guideline and the guideline in a direction perpendicular to the extension direction of the guideline is within a predetermined value. For example, when it is determined that the deviation between the guideline and the transport vehicle in a direction perpendicular to the guideline exceeds a predetermined value, the direction (angle) of the transport vehicle can be controlled to face the guideline and move forward or backward so that the transport vehicle approaches the guideline. Also, when the deviation between the guideline and the transport vehicle in a direction perpendicular to the guideline is equal to or smaller than a predetermined value, the drive control can be controlled so that the guideline and the transport vehicle are oriented in the same direction.

[0080] In the distance estimation process, the control unit 260 may calculate the distance from the current position to the destination position based on the difference between the current position acquired from the position estimation unit and the destination position acquired from the storage unit. Alternatively, the control unit 260 may perform image recognition of a two-dimensional code provided on the floor or wall and acquire information on the distance (the distance from the current position to the destination position) associated with the two-dimensional code.

[0081] The control unit 260 may execute a driving control process based on speed information acquired by a speed sensor of the transport vehicle. The type of speed sensor is not particularly limited, and any sensor, such as a sensor detecting the number of rotations or rotation speed of the drive wheels, or a camera, may be used as the speed sensor. The control unit 260 detects the speed of the transport vehicle at predetermined intervals, determines whether the detected speed matches the target speed, and performs driving control while repeatedly adjusting the speed. That is, the control unit 260 determines whether the difference between the actual speed and the target speed is equal to or less than a predetermined value (e.g., a predetermined threshold value). If the difference is equal to or less than the predetermined value, the control unit 260 maintains control. If the difference is greater than the predetermined value, the control unit 260 decelerates or accelerates the transport vehicle to approach the target speed. By repeating this speed adjustment process, deviations from the target speed can be suppressed (reduced).

[0082] The control unit 260 can repeatedly execute the distance estimation process at predetermined regular intervals. Similarly, the control unit 260 may execute the process of estimating the position and orientation of the virtual detection unit relative to the guideline at regular intervals, or calculate the difference. This can further improve the accuracy when the virtual detection unit moves backward while positioned on the guideline.

[0083] The control unit 260 may acquire information such as the current position, the distance to the destination position, and / or the target speed at that point, associated with the two-dimensional code by scanning the two-dimensional code with a sensor (camera). For example, if information on the target speed is associated with the two-dimensional code, the guided vehicle can acquire the information on the target speed from the two-dimensional code and perform the above-mentioned speed control.

[0084] In the driving control method of this embodiment, when a predetermined condition is met, the control unit 260 switches from the normal operation mode to a virtual sensor use mode in which the guided vehicle operates so that the virtual detection unit is positioned on the guideline (S101), as shown in FIG. 17 . The predetermined condition may be, for example, a case where the guided vehicle moves backward, but is not limited to this. It may also be when a user input requesting switching is received, or when switching instruction information previously associated with a two-dimensional code read by a camera (sensor) is recognized. The normal operation mode may be a mode in which the guideline is detected by the line detection unit 16 while the guided vehicle moves forward along the guideline, but it may also be another mode, such as an autonomous driving mode.

[0085] Then, the control unit 260 (position and orientation acquisition unit) estimates the relative position and relative angle θ of the line detection unit 16 with respect to the guideline. For example, when the line detection unit 16 is located on the guideline, the distance from the guideline to the line detection unit 16 is 0 (zero).

[0086] The control unit estimates the guideline's relative position of the virtual detection unit with respect to the guideline based on the position information and posture information of the transport vehicle with respect to the guideline and the relative position information of the virtual detection unit with respect to the specific location (S102). The control unit estimates the distance D from the guideline to a specific location (such as the center) of the virtual detection unit 116 based on, for example, the distance (relative position) from the guideline to the line detection unit 16 and the relative angle θ, and the distance L1 from the line detection unit 16 to the virtual detection unit 116, which are stored in advance in a storage unit. The distance D can be calculated using the formula D = L1 × sin θ. If the line detection unit 16 is not located on the guideline, the distance D can be calculated by adding or subtracting the distance from the guideline to the line detection unit 16 (depending on the direction as viewed from the guideline) from the above L1 × sin θ.

[0087] The control unit controls the operation of the guided vehicle based on the estimated position of the virtual detection unit relative to the guideline (S103). For example, the guided vehicle may be rotated until the virtual detection unit is positioned on the guideline, or the guided vehicle may be rotated gradually while moving backward to bring the virtual detection unit closer to the guideline. The control unit 260 repeats the processes of S102 and S103 above, and when it detects that the guided vehicle has reached the destination position, it stops the guided vehicle, and the movement process to the destination position is completed.

[0088] The control unit can control the drive unit so that the distance D is a predetermined specific value (e.g., 5 mm or less, 1 mm or less, 0.5 mm or less, 0 mm, etc.), just as in the case of moving forward while reading the guideline with the line detection unit 16. For example, the left and right drive wheels can be rotated in opposite directions or at different rotation speeds, thereby turning the guideline in a direction that causes the virtual detection unit 116 to approach the guideline, thereby making it possible to make the distance D equal to or less than the predetermined specific value. In this case, the guided vehicle may move forward or backward.

[0089] The control unit repeatedly acquires the relative position of the virtual detection unit with respect to the guideline at predetermined intervals, and if the position of the virtual detection unit deviates from the guideline, controls the drive unit so that the virtual detection unit is positioned on the guideline, and the transport vehicle moves to the destination position while backing up. Note that the relative position of the virtual detection unit with respect to the guideline may be acquired not only when backing up but also when forwarding, and the drive unit may be controlled so that the virtual detection unit is positioned on the guideline.

[0090] The control unit 260 may execute a process of calculating the distance from the current position of the transport vehicle to the destination position based on the difference between the current position acquired from the position estimation unit 265 and the destination position acquired from the storage unit. Alternatively, the distance d may be acquired by associating information on the distance d with a two-dimensional code laid on the floor and reading the code with the transport vehicle.

[0091] The control unit 260 may control the traveling speed of the transport vehicle based on speed information acquired by a speed sensor of the transport vehicle. For example, the control unit 260 compares the target speed determined based on the distance d with the current speed of the transport vehicle, and controls the transport vehicle to accelerate if the current speed is slower than the target speed, and controls the transport vehicle to decelerate if the current speed is faster than the target speed.

[0092] The control unit 260 may execute processes to calculate the distance to the destination position, determine the target speed, and control the speed at predetermined fixed intervals. The fixed interval may be, for example, 0.01 seconds, 0.02 seconds, 0.05 seconds, 0.1 seconds, 1 second, etc., and may be stored in advance in the storage unit. The control unit 260 may execute processes to calculate the distance d at shorter intervals as the distance d decreases (i.e., as the vehicle approaches the destination), rather than at fixed intervals. On the other hand, the control unit 260 may execute processes to calculate the distance d at shorter intervals as the distance d increases. Similar to the process of calculating the distance d, the control unit 260 may acquire or estimate its own position and acquire or estimate its speed at regular or irregular intervals.

[0093] The control unit 260 may calculate an appropriate torque value for the motor that drives the drive wheels based on the traveling speed v. For example, the control unit 260 may calculate a torque value corresponding to the traveling speed v based on a relational expression between the traveling speed v and the motor torque value that is stored in advance in the storage unit. By controlling the motor based on this appropriate torque value, it is possible to further improve stopping accuracy.

[0094] The control unit 260 may acquire the current position by scanning a two-dimensional code placed on the road surface. This allows for quick acquisition of current position information in a simple manner. When the control unit detects that the guided vehicle has passed the destination position based on the current position information, it may also control the travel so that the guided vehicle returns to the destination position. As shown in FIG. 7, the control unit 260 can control the speed of the guided vehicle when it is moving backward to the destination position in the same way as when it is moving forward. Furthermore, when moving backward to the destination position, the control may be different from that when it is moving forward.

[0095] In addition, the transport vehicle may detect its attitude (angle) relative to the extension direction of the travel path (e.g., relative to the extension direction of the guide line) simultaneously with the speed control along the guideline. If the transport vehicle deviates from the travel path direction by a predetermined value (e.g., 1°, 5°, etc.) or more, it may perform attitude control (turn) to bring its attitude closer to the travel path direction. By checking and correcting the angle deviation in this way, the accuracy of the stopping position can be further improved. Furthermore, such attitude detection may be performed repeatedly at predetermined intervals (a predetermined fixed period or a non-fixed fixed period). Furthermore, the control unit may detect the traveling direction (front direction of the transport vehicle) using, for example, an attitude sensor on the transport vehicle. Furthermore, the control unit may detect the extension direction of the guideline using a detection unit, or data on the position and extension direction of the guideline may be stored in advance in a map in a storage unit.

[0096] Although the preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the technical scope of the present disclosure is not limited to such examples. It is clear that a person skilled in the art of the present disclosure can conceive of various modified or altered examples within the scope of the technical idea described in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0097] The devices described herein may be implemented as stand-alone devices, or may be implemented as multiple devices (e.g., cloud servers) partially or entirely connected via a network. For example, the control unit 260 and the recording unit 220 of the transport vehicle may be implemented as different servers connected to each other via a network. In addition, in the transport system described herein, the controller 3000, the overall control device 4000, and the input / output device 5000 are configured as separate pieces of hardware connected via a network. However, some or all of the functions of the controller 3000, the overall control device 4000, and the input / output device 5000 may be implemented in the transport vehicle 10.

[0098] The series of processes performed by the device described herein may be implemented using software, hardware, or a combination of software and hardware. A computer program for implementing each function of the control unit 260 according to this embodiment may be created and installed on a PC or the like. A computer-readable recording medium storing such a computer program may also be provided. Examples of the recording medium include a magnetic disk, an optical disk, a magneto-optical disk, and a flash memory. The computer program may also be distributed, for example, via a network, without using a recording medium.

[0099] Furthermore, the processes described herein using flowchart diagrams do not necessarily have to be performed in the order shown. Some process steps may be performed in parallel. Additional process steps may be employed, and some process steps may be omitted.

[0100] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that will be apparent to those skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0101] The following configurations also fall within the technical scope of the present disclosure. (Item 1) A travel control system for a guided vehicle capable of moving along a real or virtual guideline, comprising: a control unit that controls the operation of the guided vehicle by controlling a drive unit of the guided vehicle; a position and attitude acquisition unit that acquires current position information of a specific location on the guided vehicle relative to the guideline and attitude information of the guided vehicle relative to the guideline; and a storage unit that stores in advance position information of a virtual detection unit set at a location different from the specific location of the guided vehicle relative to the specific location, wherein the control unit estimates a guideline relative position of the virtual detection unit with respect to the guideline based on the position information and attitude information of the guided vehicle with respect to the guideline and the position information of the virtual detection unit relative to the specific location, and controls the operation of the guided vehicle based on the estimated guideline relative position of the virtual detection unit. (Item 2) The travel control system according to item 1, wherein the control unit acquires a relative difference between the position of the guideline and the position of the virtual detection unit when estimating the guideline relative position of the virtual detection unit with respect to the guideline. (Item 3) The travel control system according to item 1, wherein the transport vehicle includes a guide detection unit that is disposed at the specific location and detects a real guideline, and the position and attitude acquisition unit estimates position information of the specific location on the transport vehicle relative to the guideline and attitude information of the transport vehicle relative to the guideline based on detection information from the guide detection unit. (Item 4) The travel control system according to item 1, wherein the storage unit pre-stores map data corresponding to real space and position data of a virtual guideline set on the map data, and the position and attitude acquisition unit estimates position information of the specific location on the transport vehicle relative to the guideline and attitude information of the transport vehicle relative to the guideline based on the position data of the virtual guideline on the map data and current position information and attitude information of the transport vehicle. (Item 5) The travel control system according to item 1, wherein the virtual detection unit is set at a position behind the specific location on the transport vehicle.(Item 6) The control unit determines whether the virtual detection unit is located on the guideline when the guided vehicle moves backward, and if the virtual detection unit is located on the guideline, controls the operation of the guided vehicle so that the virtual detection unit moves along the guideline. If the virtual detection unit is not located on the guideline, controls the operation of the guided vehicle so that the virtual detection unit approaches the guideline. (Item 7) The control unit is a driving control system according to item 1, wherein the drive unit has a pair of left and right drive wheels. (Item 8) The control unit is a driving control system according to item 7, wherein the specific location is located forward of the pair of left and right drive wheels. (Item 9) The control unit is a driving control system according to item 7, wherein the virtual detection unit is located rearward of the pair of left and right drive wheels. (Item 10) The control unit is a driving control system according to item 1, wherein the control unit estimates the position of the virtual detection unit relative to the guideline at predetermined regular intervals. (Item 11) The travel control system according to item 1 or 2, wherein the current position of the transported vehicle is acquired by scanning a two-dimensional code serving as the guideline installed on a road surface, a wall surface, or a ceiling surface. (Item 12) The travel control system according to item 1 or 2, wherein the virtual detection unit is set at a predetermined position on an object to be transported coupled to the transported vehicle, and the control unit estimates the position of the virtual detection unit based on position information and posture information of the object to be transported relative to the transported vehicle. (Item 13) The travel control system according to item 12, wherein the transported vehicle is provided with an object to be transported detection unit that detects the posture of the object to be transported. (Item 14) The travel control system according to item 1 or 2, wherein the control unit selects one of a plurality of pieces of position information of the virtual detection unit stored in advance based on whether an object to be transported is coupled to the transported vehicle.(Item 15) A travel control method for controlling travel of a transport vehicle that can move along a real or virtual guideline by a travel control system, wherein the travel control system comprises: a control unit that controls the operation of the transport vehicle by controlling a drive unit of the transport vehicle; a position and attitude acquisition unit that acquires relative position information of a specific location of the transport vehicle with respect to the guideline and attitude information of the transport vehicle with respect to the guideline; and a storage unit that stores in advance relative position information of a virtual detection unit set at a position different from the specific location of the transport vehicle with respect to the specific location, wherein the control unit estimates a guideline relative position of the virtual detection unit with respect to the guideline based on the position information and attitude information of the transport vehicle with respect to the guideline and the relative position information of the virtual detection unit with respect to the specific location, and controls the operation of the transport vehicle based on the estimated guideline relative position of the virtual detection unit.

[0102] DESCRIPTION OF SYMBOLS 10 Transport vehicle, 11 Connection unit, 12 Object position detection unit, 13 Drive wheel, 14 Non-drive wheel, 16 Guide line detection unit, 17 Magnetic sensor, 116 Virtual detection unit 130 Operation area, 131 Guide line, 132 Travel mode switching position, 210 Communication unit, 220 Recording unit, 230 Detection unit, 240 Input unit, 250 Display unit, 260 Control unit, 280 Wheel drive unit, 2000 Cart, 2010 Connection receiving unit, 3000 Control device, 4000 Overall control device, 5000 Input / output device, 6000 Communication network, 7000 External system

Claims

1. A travel control system for a transport vehicle that can move along a real or virtual guideline, comprising: a control unit that controls the operation of the transport vehicle by controlling the drive unit of the transport vehicle; a position and attitude acquisition unit that acquires relative position information of a specific location on the transport vehicle with respect to the guideline and attitude information of the transport vehicle with respect to the guideline; and a memory unit that stores in advance relative position information of a virtual detection unit set at a location different from the specific location of the transport vehicle with respect to the specific location, wherein the control unit estimates the guideline relative position of the virtual detection unit with respect to the guideline based on the position information and attitude information of the transport vehicle with respect to the guideline and the relative position information of the virtual detection unit with respect to the specific location, and controls the operation of the transport vehicle based on the estimated guideline relative position of the virtual detection unit.

2. The driving control system of claim 1, wherein the control unit, when estimating the guideline position of the virtual detection unit relative to the guideline, obtains the relative difference between the position of the guideline and the position of the virtual detection unit.

3. The travel control system of claim 1, wherein the transport vehicle is provided with a guide detection unit that is placed at the specific location and detects an actual guideline, and the position and attitude acquisition unit estimates relative position information of the specific location on the transport vehicle with respect to the guideline and attitude information of the transport vehicle with respect to the guideline based on the detection information of the guide detection unit.

4. The driving control system of claim 1, wherein the memory unit pre-stores map data corresponding to real space and position data of virtual guidelines set on the map data, and the position and attitude acquisition unit estimates relative position information of a specific location on the transport vehicle with respect to the guideline and attitude information of the transport vehicle with respect to the guideline based on the position data of the virtual guideline on the map data and current position information and attitude information of the transport vehicle.

5. The travel control system according to claim 1, wherein the virtual detection unit is set at a position behind the specific location of the transport vehicle.

6. The travel control system of claim 1, wherein the control unit determines whether the virtual detection unit is located on the guideline when the transported vehicle retreats, and if the virtual detection unit is located on the guideline, controls the operation of the transported vehicle so that the virtual detection unit moves along the guideline, and if the virtual detection unit is not located on the guideline, controls the operation of the transported vehicle so that the virtual detection unit approaches the guideline.

7. The cruise control system according to claim 1, wherein the drive unit has a pair of left and right drive wheels.

8. The cruise control system according to claim 7, wherein the specific location is located forward of the pair of left and right drive wheels.

9. The cruise control system according to claim 7, wherein the virtual detection unit is located rearward of the pair of left and right drive wheels.

10. The cruise control system according to claim 1, wherein the control unit estimates the position of the virtual detection unit relative to the guide line at predetermined regular intervals.

11. A travel control system according to claim 1 or 2, wherein the current position of the transport vehicle is acquired by scanning a two-dimensional code serving as the guideline installed on a road surface, a wall surface, or a ceiling surface.

12. A travel control system as described in claim 1 or 2, wherein the virtual detection unit is set at a predetermined position on the object to be transported connected to the transport vehicle, and the control unit estimates the position of the virtual detection unit based on relative position information and attitude information of the object to be transported with respect to the transport vehicle.

13. The travel control system according to claim 12, wherein the transport vehicle is provided with a transport object detection unit that detects the posture of the transport object.

14. A travel control system as described in claim 1 or 2, wherein the control unit selects one of the position information of a plurality of virtual detection units stored in advance based on whether or not an object to be transported is connected to the transport vehicle.

15. A travel control method for controlling the travel of a transport vehicle that can move along a real or virtual guideline using a travel control system, wherein the travel control system comprises: a control unit that controls the operation of the transport vehicle by controlling a drive unit of the transport vehicle; a position and attitude acquisition unit that acquires relative position information of a specific location on the transport vehicle with respect to the guideline and attitude information of the transport vehicle with respect to the guideline; and a memory unit that stores in advance relative position information of a virtual detection unit set at a location different from the specific location of the transport vehicle with respect to the specific location, wherein the control unit estimates the guideline relative position of the virtual detection unit with respect to the guideline based on the position information and attitude information of the transport vehicle with respect to the guideline and the relative position information of the virtual detection unit with respect to the specific location, and controls the operation of the transport vehicle based on the estimated guideline relative position of the virtual detection unit.

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