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

Abstract

To provide a travel control system of transport vehicles capable of improving both of stop accuracy and travel efficiency, and travel control method of the transport vehicles.SOLUTION: The present disclosure provides a control system of transport vehicles for determining whether a distance d from a current position to a target position is a prescribed value or less, the control system of the transport vehicle including a control part which, when it is determined that the distance d is the prescribed value or less, controls a traveling speed of the transport vehicle such that a relation among the distance d, the traveling speed v and a constant k satisfies an expression [A]: v=sqrt(2*k*d).SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In recent years, the use of autonomous automated guided vehicles has been put to practical use for transporting luggage within facilities such as factories and warehouses. For example, there are known guided vehicles that run along predetermined guidelines laid out within a facility, that run autonomously without guidelines, or that run in a combination of these ways. Patent Document 1 proposes a technology for running a guided vehicle to a destination by setting a travel speed for each section of the travel route. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-053837 A Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 discloses that when a transport vehicle travels along a line, the transport vehicle travels at a set speed of either 1st to 4th gears or creep speed. However, there is room for improvement in terms of achieving both improved stopping accuracy and improved travel efficiency.

[0005] Therefore, the present disclosure has been made in consideration of at least one of the above problems, and its purpose is to provide a transport vehicle travel control system and a transport vehicle travel control method that can achieve both improved stopping accuracy and improved travel efficiency. [Means for solving the problem]

[0006] According to the present disclosure, there is provided a travel control system for a transport vehicle, comprising: Determine whether the distance d from the current position to the destination position is equal to or less than a predetermined value; There is provided a transport vehicle driving control system, characterized in that it includes a control unit that controls the traveling speed of the transport vehicle when it is determined that the distance d is equal to or less than a predetermined value so that the relationship between the distance d, the traveling speed v, and the constant k satisfies equation [A]. v = sqrt(2*k*d) [A]

[0007] According to the present disclosure, there is provided a method for controlling travel of a transport vehicle, comprising: The control unit determines whether or not a distance d from the current position to the destination position is equal to or less than a predetermined value; There is provided a method for controlling the running of a transport vehicle, characterized in that when it is determined that the distance d is equal to or less than a predetermined value, the running speed of the transport vehicle is controlled so that the relationship between the distance d, the running speed v, and the constant k satisfies equation [A]. v = sqrt(2*k*d) [A] Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a transport vehicle travel control system and a transport vehicle travel control method that can achieve both improved stopping accuracy and improved travel efficiency. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view showing an example of a hardware configuration of a transport vehicle according to the present embodiment. [Diagram 2] FIG. 2 is a bottom view showing an example of a hardware configuration of the transport vehicle according to the embodiment. [Diagram 3] FIG. 2 is a diagram illustrating an example of a hardware configuration when a transport vehicle and a towing cart according to the present embodiment are coupled together. [Figure 4] FIG. 11 is a diagram illustrating another example of a hardware configuration when the transport vehicle and the towing cart according to the present embodiment are coupled together. [Diagram 5] FIG. 2 is a diagram showing a configuration example of a motion area according to the present embodiment; [Figure 6]13 is a diagram showing the positional relationship between the guide line and the transport vehicle when the guide line detection unit detects the two-dimensional code that constitutes the guide line. FIG. [Figure 7] 13 is a bottom view showing the positional relationship between the guide line and the transport vehicle when the guide line detection unit detects the magnetic tape that constitutes the guide line. FIG. [Figure 8] FIG. 1 is a diagram showing an example of an overall configuration diagram of a conveying system according to an embodiment of the present invention; [Figure 9] FIG. 2 is a configuration diagram of an overall control device according to the present embodiment. [Figure 10] FIG. 2 is a diagram showing a functional configuration of a transport vehicle according to the present embodiment. [Figure 11] 10 is a diagram showing an example of the travel speed of a transport vehicle in this embodiment based on the travel distance. FIG. [Figure 12] 10 is a diagram showing an example of the travel speed of a transport vehicle based on time in this embodiment. FIG. [Figure 13] FIG. 11 is a diagram showing an example of the travel speed of a transport vehicle based on the travel distance as a comparative example. [Figure 14] FIG. 11 is a diagram showing an example of the travel speed of a transport vehicle based on time as a comparative example. [Figure 15] FIG. 2 is a diagram showing a control flow of a control system in the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0011] In logistics warehouses and manufacturing plants, it is required to stop the transported objects such as transport vehicles, carts, and pallets at a predetermined position and orientation in a predetermined manner in order to coordinate with on-site work. For example, it is required to transport the transported objects so that the workers can pick up the luggage placed on the transported objects without moving by stopping the cart at a coordinated position with the belt conveyor or by pulling up next to the worker's work position. In order to coordinate with the belt conveyor as described above or to pull up next to the worker's work position, a highly accurate transport operation is required. In addition, simply slowing down the speed to improve the accuracy of the stopping position reduces the transport efficiency. In addition, when transporting a relatively heavy transported object, a large inertial force is applied to the transport vehicle, making it difficult to manage the speed, and it is also difficult to stop the vehicle at the intended position.

[0012] The hardware configuration of the transport vehicle and the towed dolly will be described with reference to Figs. 1 to 4. Fig. 1 is a perspective view showing an example of the hardware configuration of the transport vehicle according to this embodiment. The transport vehicle in this example is an unmanned transport vehicle, but can also be applied to various vehicles on which people can ride. Arrow 15 in Fig. 1 indicates the traveling direction of the transport vehicle. As shown in Fig. 1, the transport vehicle includes a coupling unit 11 for switching between a coupled state and a non-coupled state with the dolly, an object position detection unit 12 for detecting objects around the transport vehicle, drive wheels 13, and non-driven wheels 14.

[0013] Moreover, a connecting section 11 and an object position detection section 12 are mounted on the upper surface side of the transport vehicle. The connecting section 11 is, for example, composed of an actuator, and is configured such that when connecting to a dolly, the actuator is extended upward to connect to a connection receiving section (not shown) on the dolly side, and when disconnecting, the actuator is retracted to disconnect the connecting section from the connection receiving section on the dolly side. Moreover, the connecting section 11 is disposed at four positions surrounding the drive wheels 13 of the transport vehicle on a plane, and can be connected to the dolly at five positions. In this embodiment, an example having four connecting sections will be described, but the number of connecting sections does not necessarily have to be five, and any number of one or more can be selected.

[0014] 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 irradiating a laser light and measuring the time it takes for the laser 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, 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, an example has been shown in which the object position detection unit 12 is disposed on the top surface of the transport vehicle at the front in the traveling direction, but instead, it may be disposed on the front side in the traveling direction. Also, it may be disposed not only at the front but also at the rear side or both left and right sides in the traveling direction.

[0015] The object position detection unit 12 may be configured to detect objects in a 360-degree periphery of the transport vehicle, but is configured to be able to detect objects at least ahead in the travel direction 15 of the transport vehicle.

[0016] FIG. 2 is a bottom view showing an example of the hardware configuration of the 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 with respect to the travel direction 15 of the transport vehicle, and non-driven wheels 14 are provided in front of and behind each of the drive wheels 13. The drive wheels 13 are wheels that 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. In addition, the control unit can control the rotation speed and rotation direction of each drive wheel individually, so that the transport vehicle can run in a curve or turn the transport vehicle on the spot. The non-driven wheels 14 are wheels that are not driven and passively rotate as the transport vehicle moves with the drive wheels 13. The non-driven wheels 14 have, for example, a fork that fixes the wheel and the axle, and the fork is composed of a rotating caster that is rotatably connected to the bottom member of the transport vehicle. Therefore, the wheel rotation direction of the non-driven wheels 14 changes passively according to the travel direction and rotation operation of the transport vehicle. Figure 2 illustrates an example of the hardware configuration of a transport vehicle with two driven wheels and four non-driven wheels at the four corners, but 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 the four-wheel configuration.

[0017] A guide line detector 16 for detecting the guide line is provided on the bottom of the transport vehicle. The guide line detector 16 is preferably provided ahead of the drive wheels 13 in the travel direction of the transport vehicle. This makes it easier for the transport vehicle to travel along the guide line when traveling at a curved guide line, and also allows the transport vehicle and the towing cart to receive information from the guide line as soon as possible when traveling, thereby enabling them to quickly execute processing such as stopping. The guide line detector uses a sensor according to the type of guidance method as described above. When the electromagnetic induction method is used as the guidance method, a pickup coil is used as the sensor for the guide line detector. When the magnetic induction method is used, a magnetic sensor is used. When the image recognition method is used, a camera is used.

[0018] 3 shows an example of the hardware configuration when the transport vehicle and towing dolly according to this embodiment are coupled, specifically, showing an example in which the transport vehicle 10 is coupled to the dolly while slipping under the dolly to be towed. At this time, a cone-shaped coupling receiver is disposed on the bottom of the dolly at a position corresponding to the cone-shaped coupling part 11, and the dolly can be coupled by extending the coupling part 11 upward, and the coupling part 11 can be released from the dolly.

[0019] FIG. 4 shows another example of the hardware configuration when the transport vehicle and the towing dolly according to the present embodiment are coupled together. In the example shown in FIG. 4, the transport vehicle is coupled to the dolly while being positioned beside the dolly 2000. The dolly has a coupling receiving part 2010 that couples with at least a part of the coupling part 11 of the transport vehicle, and can be coupled to the dolly by extending the coupling part 11 upward, and can be released from the dolly by contracting the coupling part 11. In FIG. 3 and FIG. 4, an example is shown in which the coupling part 11, which is composed of an actuator or the like on the upper surface of the transport vehicle, is extended and contracted in the vertical direction to couple and release the coupling with the dolly, but the coupling method between the transport vehicle and the dolly is not limited to this, and other coupling methods may be used. In addition, the transported object coupled to the transport vehicle is not limited to the dolly, and may be, for example, a pallet or a cabinet without wheels. When transporting a pallet or a cabinet, the transport vehicle slips under the pallet or cabinet and is coupled in a state of lifting the pallet or cabinet.

[0020] 5 is a diagram showing a configuration example of the operation area 130 according to the present embodiment. As shown in FIG. 3, a guide line 131 is laid in the operation area 130, and when a guided vehicle traveling in an autonomous traveling mode detects the guide line 131 at a preset traveling mode switching position 132, the traveling control mode is switched from the autonomous traveling mode to the guided traveling mode. Conversely, when a guided vehicle traveling in the guided traveling mode on the guide line enters the preset traveling mode switching position 132, the traveling control mode is switched from the guided traveling mode to the autonomous traveling mode. In order to guide a guided vehicle to a position close to a shelf or a belt conveyor on which luggage is stored, or a work position of a worker, a track formed by the guide line 131 is laid at a position close to the shelf or work position via multiple branch points.

[0021] The guided vehicle 10 traveling in an autonomous travel area where no guide line is laid in the autonomous travel mode changes its travel mode to the guided travel mode in which it follows the guide line on the condition that it enters the travel mode switching position 132 and detects the guide line 131. On the other hand, when the guided vehicle traveling in the guided travel mode on the guide line enters the 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.

[0022] As the induction lines 111 and 131 shown in Fig. 5, induction lines of various induction methods that have been used conventionally can be applied, as described later. Specifically, for example, an electromagnetic induction method in which a pickup coil on the carrier side detects a magnetic field generated by passing a weak alternating current through a metal wire installed as an induction line, a magnetic induction method in which a magnetic sensor on the carrier side reads a magnetic tape laid on the floor as an induction line, or an image recognition method in which a camera on the carrier side takes an image of a code (such as a barcode or a two-dimensional code) laid on the floor as an induction line and processes the image can be applied.

[0023] 6 shows the positional relationship between the guide line and the transport vehicle when the two-dimensional code constituting 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 having code information printed on a two-dimensional plane as shown in the two-dimensional code 1000, in a line in the direction of laying the guide line. When the guide line detection unit 16 detects the two-dimensional code, it acquires the position information of the two-dimensional code based on the code information acquired from the two-dimensional code.

[0024] FIG. 7 shows the positional relationship between the guide line and the carrier when the magnetic tape constituting the guide line is detected by the guide line detection unit 16. The guide line detection unit 16 shown in FIG. 13 is configured to have a plurality of magnetic sensors 17 for detecting the magnetic tape arranged horizontally toward the traveling direction of the carrier. Each of the magnetic sensors 17 provided in the guide line detection unit 16 outputs a detection signal indicating whether or not the magnetic tape is detected. In the case shown in FIG. 22, the three magnetic sensors 17A located in the center of the guide line detection unit 16 detect the magnetic tape, and the two magnetic sensors 17B on each side of the guide line detection unit 16 do not detect the magnetic tape.

[0025] <Conveyor system configuration> Next, the configuration of the transport system of this embodiment will be described. Figure 8 is a diagram showing an example of the overall configuration of the transport system according to this embodiment. The transport system 1000 includes a plurality of transport vehicles (10a, 10b), a dolly 2000 which is a transported object, a control device 3000 which can display the state of the transport vehicles or input commands to the transport vehicles, a general control device 4000 which manages information required for the operation of the transport vehicles, an input / output device 5000 which displays information of the general control device and inputs information to the general control device, and a communication network 6000 which communicably connects the plurality of transport vehicles (10a, 10b), the control device 3000, and the general control device 4000.

[0026] 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 facility 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 acquiring information on the operational progress of the manufacturing work from the manufacturing management system, the transport volume and transport route by the transport vehicle can be dynamically adjusted according to the progress of the manufacturing work.

[0027] As another example, in the case where the conveyance system 1000 is introduced into a logistics warehouse and conveys the incoming goods from an entrance to a storage warehouse when the goods are brought into the warehouse by truck or the like, and conveys the goods to be shipped from the storage warehouse to an exit when the goods are shipped from the warehouse, the conveyance system 1000 performs inter-system cooperation with a logistics management system as an external system 7000. In this case, by acquiring information related to the incoming goods and the outgoing goods from the logistics management system, the transportation amount and transportation route by the conveyance vehicle can be changed.

[0028] 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 communicatively 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 the other transport vehicles 10. The transport vehicle 10 is also electrically connected to the cart 2000 or communicatively connected via short-range communication means, and is configured to be able to receive information on the connection state and identification information of the cart from the cart.

[0029] The control device 3000 has a function of displaying status information of each transport vehicle and a function of inputting commands to a specified transport vehicle. For example, the status information of the transport vehicle displayed on the control device includes identification information of each transport vehicle, position (coordinates, position on a map), speed, direction, travel history, information on the charge level of a battery mounted on the transport vehicle and serving as the power source for the transport vehicle, and identification information of transported objects such as a dolly transported by the transport vehicle. Examples of commands input to the transport vehicle include command information on the destination (destination position) of the transport vehicle, operation commands for coupling and uncoupling with the dolly, commands to start the transport vehicle, commands to stop the transport vehicle, commands to return to the charging station, and the like.

[0030] 9 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 transport vehicles operated in a facility area, an operation scenario management unit 4020 that manages operation scenarios of the multiple transport vehicles, a map management unit 4030 that generates and updates a map of the work area based on detection information of the transport vehicles including detection information of the guide lines acquired by the guide line detection unit of the transport vehicles, an abnormality determination unit 4040 that determines abnormalities of the guide lines and the transport vehicles based on the detection information of the transport vehicles, and a communication unit 4050 that communicates with an external input / output device 5000 and a communication network 6000.

[0031] The status information of the transport vehicles recorded by the status information recording unit 4010 includes, for example, obstacle detection positions detected by the multiple transport vehicles during operation, guide line detection positions, history information of the travel positions of the transport vehicles, and further, information on the battery charge amount, identification information of the dolly connected to the multiple transport vehicles, operation modes (guided travel mode or autonomous travel mode) of the multiple transport vehicles, various other detection information detected by the detection unit 230 of the transport 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 destination of each of the multiple transport vehicles, the contents of multiple operations to be performed until reaching the destination, the operation sequence of the multiple operations, and switching conditions for the multiple operations.

[0032] The map management unit 4030 generates a map including the position information of obstacles and guide lines in the working area based on the obstacle detection position detected by the guided vehicle, the guide line detection position, and the history information of the travel position of the guided vehicle. Furthermore, the map management unit 4030 updates the position information of the guide lines registered in the map based on the information of the detection position of the guide lines accumulated by one or more guided vehicles.

[0033] The abnormality determination unit 4040 determines abnormalities in the guide lines and the transport vehicle based on the position information of the guide lines registered in the map information and the detection information of the transport vehicle including the detection position information of the guide lines detected by the transport vehicle. Details of the control flow for determining abnormalities in the guide lines and the vehicle by the abnormality determination unit 4040 will be described later.

[0034] The input / output device 5000 displays information recorded in the state information recording unit 4010 of the overall control device 4000, map information (including map update information), and the determination result by the abnormality determination unit, and can add or update a new operation scenario by inputting an operation scenario 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, operation contents for entering the guided travel area 110 and reaching the working area A, operation switching conditions, and the like.

[0035] <Functions of the transport vehicle> The functions of the transport vehicle will be described with reference to Fig. 10. Fig. 10 is a diagram showing the functional configuration of the transport vehicle according to this embodiment. The transport vehicle 10 includes a communication unit 210 that communicates with a dolly 2000 outside the transport vehicle and a communication network 6000, a recording unit 220 (including a storage unit), a detection unit 230 equipped with various sensors described later, a coupling unit 11 for coupling with the dolly, a wheel driving unit 280 that drives the wheels, an input unit 240, a display unit 250, and a control unit 260 that controls the operations of the wheel driving unit 280, etc.

[0036] 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 can store information such as the destination position, movement route, and movement history of the transport vehicle. 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, and the like.

[0037] 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 irradiating a laser beam and measuring the time it takes for the laser beam to bounce back after hitting the object, 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 photographed image. The control unit can estimate information on 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 including a GNSS or the like that detects the current position of the transport vehicle, and a speed sensor that detects the speed of the transport vehicle.

[0038] As described above, the guide line detection unit 16 uses a sensor according to the type of guide 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. When the guide line detection unit is located directly above the guide line, it detects the guide line and outputs a detection signal. In addition to the detection signal of the guide line, 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 the information of the detected code, and further, by analyzing the image information of the code, relative angle information between the guide line and the carrier can be generated.

[0039] 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 detection information of the number of rotations and the information of 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). As an alternative, it is also possible to apply a means for detecting the travel speed of the transport vehicle using a millimeter wave sensor that irradiates a floor surface with millimeter waves and detects reflected waves, and estimating the travel distance by integrating the travel speed. Also, any method for measuring the travel distance or acquiring the travel speed other than the above-mentioned methods can be applied.

[0040] The collision detection unit 234 has a function of detecting that the transport vehicle collides with an object or a person. Specifically, it is possible to 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 also possible to apply a means of providing a physical switch together with a bumper at the front of the transport vehicle in the traveling direction, and determining that a collision has occurred when the physical switch is pressed. In addition, a collision detection method other than the above can be applied. When the collision detection unit 234 detects a collision, it stops the transport vehicle, records at least one of the collision occurrence information and the collision occurrence position information in the recording unit, and notifies the information to the general control device 4000 and the control device 3000. The attitude detection unit 235 detects the direction (attitude) of the vehicle based on a magnetic compass, information on the rotation speed of the left and right drive wheels, or steering information of the wheels.

[0041] The charge amount detection unit 236 detects the charge amount of the battery, which is the power source of the transport vehicle. When the charge amount detected by the charge amount detection unit 236 becomes equal to or less than a predetermined value, it 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 general control device 4000 and the control device 3000. Furthermore, when it is detected that the charge amount is equal to or less than a predetermined value, in addition to the above processing, it may be configured to automatically move to a charging spot and charge. The predetermined value for 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.

[0042] The input unit 240 is composed of a physical switch or a touch panel mounted on the transport vehicle, and allows the user to directly input operation commands, etc. to the transport vehicle. The display unit 250 is composed of, 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 currently running operation scenario, etc.).

[0043] 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.

[0044] 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 a command 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 a command 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.

[0045] The position estimation unit 265 can estimate the position at a predetermined time including the current position of the vehicle in the entire travel area based on the travel distance detected by the travel distance detection unit 233, the information on the direction of the vehicle detected by the attitude detection unit 235, and the map information of the entire area recorded in the recording unit 220. Alternatively, it is also possible to estimate the position of the vehicle in the entire travel area based on the information on the distance and direction from the vehicle to an object measured by the object position detection unit 12 and the map information of the entire area recorded in the recording unit 220. Alternatively, when the vehicle is traveling on a guide line formed by a two-dimensional code, it is also possible to estimate the position of the vehicle in the entire travel area based on the identification information of the two-dimensional code and the map information. The position estimation unit 265 can also acquire position information by a GNSS or the like provided in the carrier vehicle.

[0046] The position estimation unit 265 can estimate the position where the object exists 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. In addition, based on the vehicle position information when the guide line detection unit 16 detects the guide line, it estimates the installation position of the guide line.

[0047] 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 driving unit 281 and the left wheel driving unit 282 of the wheel driving unit 280. The right wheel driving unit 281 and the left wheel driving unit 282 are composed of, for example, a motor, and by individually controlling the rotation speed and rotation direction of each drive wheel, it becomes possible to make the transport vehicle travel in a curve with an arbitrary trajectory radius or to rotate the transport vehicle to change its direction.

[0048] The control unit 260 determines whether the distance d from the current position to the destination position is equal to or less than a predetermined value, and when it determines that the distance d is equal to or less than the predetermined value, it can control the travel speed of the transport vehicle so that the relationship between the distance d, the travel speed v, and the constant k satisfies the formula [A]. That is, by applying the numerical value of the distance d and the preset constant k to the formula [A], the target travel speed v at that time point is determined, and the control unit can control the drive wheels (the motor in this example) to achieve that speed v. v = sqrt(2*k*d) [A]

[0049] Here, the predetermined value from the current position to the destination position for determining whether or not to apply formula [A] may be any numerical value, such as 10 cm, 50 cm, 1 m, 10 m, 20 m, etc., and is set in advance and stored in the memory unit.

[0050] In the travel control method of this embodiment, the control unit 260 calculates a distance d to the destination position during the process of moving to the destination position (S101), for example, as shown in Fig. 15. Note that while the distance to the destination position is equal to or greater than a predetermined distance, the transportation vehicle is controlled to travel at a maximum speed (vmax) among allowable speeds in order to increase transportation efficiency.

[0051] The control unit 260 judges whether the distance d is equal to or smaller than a predetermined value (e.g., 10 m) (S102). If the distance d exceeds the predetermined value, the current speed (vmax) is maintained, and if the distance d is equal to or smaller than the predetermined value, the control unit 260 calculates a target speed according to the distance d based on the above formula [A] (S103).

[0052] The control unit 260 then controls the drive wheels to perform running control so as to achieve the speed calculated in S103 (S104).

[0053] The control unit 260 repeats the above steps S101 to S104 until the target position is reached. This allows the speed to be increased until the target position is approached (the distance d becomes equal to or less than a predetermined value), and once the target position is approached, appropriate speed management allows for stable running and improved stopping accuracy. In other words, it is possible to achieve both improved stopping accuracy of the transport vehicle and improved running efficiency.

[0054] Here, Fig. 11 is a diagram showing an example of the moving speed of the transport vehicle in this embodiment based on the moving distance, Fig. 12 is a diagram showing an example of the moving speed of the transport vehicle based on the time, Fig. 13 is a diagram showing an example of the moving speed of the transport vehicle as a comparative example based on the moving distance, and Fig. 14 is a diagram showing an example of the moving speed of the transport vehicle of Fig. 13 based on the time.

[0055] For example, when trying to reduce the speed linearly according to the distance x as shown in Fig. 13, the speed according to the time t becomes nonlinear as shown in Fig. 14, and there is a risk that the traveling becomes unstable as the target position is approached. In particular, when a heavy object is being transported, it is difficult to move stably at a low speed.

[0056] On the other hand, according to this embodiment, for example, as shown in FIG. 12, the degree of speed reduction according to time t becomes linear, so that driving is stable even when approaching the destination position, and further, as shown in FIG. 11, the driving distance at low speed is also shortened, so that the travel time to the destination position is also shortened.

[0057] The control unit 260 may execute a process of calculating the distance d 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.

[0058] The control unit 260 may control the travel 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 smaller than the target speed, and controls the transport vehicle to decelerate if the current speed is larger than the target speed.

[0059] The control unit 260 may execute a process of calculating the distance d at every predetermined fixed period. The fixed period may be, for example, 0.01 seconds, 0.02 seconds, 0.05 seconds, 0.1 seconds, 1 second, etc., and may be stored in the storage unit in advance. The control unit 260 may execute a process of calculating the distance d at a shorter period as the distance d becomes smaller (i.e., closer to the destination) without being limited to a fixed period. On the other hand, the control unit 260 may execute a process of calculating the distance d at a shorter period as the distance d becomes larger. The control unit 260 can acquire or estimate its own position and acquire or estimate its speed at every fixed or non-fixed predetermined period, similar to the process of calculating the distance d.

[0060] 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 torque value corresponding to the traveling speed v may be calculated 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 the appropriate torque value, it is possible to further improve the stopping accuracy.

[0061] The control unit 260 may acquire the current position by scanning a two-dimensional code placed on the road surface. This allows the current position information to be acquired quickly and easily. When the control unit detects that the carrier vehicle has passed the destination position based on the current position information, the control unit can also control the travel of the carrier vehicle to return to the destination position.

[0062] In the above embodiment, the control mode is changed when the distance d to the destination position is greater than a predetermined value, and from the point when the distance d becomes equal to or less than the predetermined value to the destination position, and the travel of the transport vehicle is controlled so that the travel speed satisfies the formula [A]. However, the control mode may be further switched before the transport vehicle reaches the destination position. For example, when the distance d to the destination position becomes equal to or less than a first value (the above-mentioned predetermined value), the travel speed may be controlled in a first mode so as to satisfy the formula [A], and then, when the distance d becomes equal to or less than a second value smaller than the first value, the control mode of the transport vehicle may be controlled in a second mode. That is, the control unit may switch the control mode of the transport vehicle in two stages according to the distance d.

[0063] In the second mode, the moving speed may be a predetermined constant speed, or may be a speed that gradually decreases according to the distance d at a rate different from that in the first mode. When the speed is gradually decreased in the second mode, the speed may be decreased as a linear function (linearly) or as a quadratic function with the distance to the destination (travel distance x) as the horizontal axis.

[0064] In the second mode, the attitude (angle) of the transport vehicle with respect to the extension direction of the travel path (for example, with respect to the extension direction of the guide line) may be detected, and if the transport vehicle deviates from the travel path direction by a predetermined value (for example, 1°, 5°, etc.) or more, the attitude may be controlled (turned) so that the attitude approaches the travel path direction. In this way, the accuracy of the stop position can be further improved by checking and correcting the angle deviation. In addition, such detection of the attitude may be repeated every predetermined period (a predetermined fixed period, or a non-fixed fixed period). In addition, the control unit can detect the traveling direction (front direction of the transport vehicle) by, for example, an attitude sensor of the transport vehicle. In addition, the control unit may detect the extension direction of the guideline by the detection unit, or data on the position and extension direction of the guideline may be stored in advance in a map of the storage unit.

[0065] Although the preferred embodiment of the present disclosure has been described in detail above with reference to the attached drawings, the technical scope of the present disclosure is not limited to such examples. It is clear that a person having ordinary knowledge in the technical field of the present disclosure can conceive of various modified or amended examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present disclosure.

[0066] The devices described in this specification may be realized as a single device, or may be realized by a plurality of 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 realized by different servers connected to each other via a network. In addition, in the transport system described in this specification, an example has been described in which the controller 3000, the overall control device 4000, and the input / output device 5000 are configured as separate hardware connected via a network, but 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.

[0067] The series of processes performed by the device described in this specification may be realized using any of software, hardware, and a combination of software and hardware. A computer program for realizing each function of the control unit 260 according to this embodiment may be created and implemented in a PC or the like. A computer-readable recording medium in which such a computer program is stored may also be provided. The recording medium may be, for example, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, or the like. The above computer program may also be distributed, for example, via a network, without using a recording medium.

[0068] In addition, 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.

[0069] In addition, the effects described in this specification are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that are apparent to a person skilled in the art from the description of this specification, in addition to or in place of the above effects.

[0070] Note that the following configurations also fall within the technical scope of the present disclosure. (Item 1) A travel control system for a transport vehicle, Determine whether the distance d from the current position to the destination position is equal to or less than a predetermined value; A travel control system for a transport vehicle, comprising a control unit that controls the travel speed of the transport vehicle when it is determined that the distance d is equal to or less than a predetermined value so that the relationship between the distance d, the travel speed v, and a constant k satisfies formula [A]. v = sqrt(2*k*d) [A] (Item 2) 2. The cruise control system according to claim 1, wherein the control unit executes a process of calculating the distance d based on a difference between the current position acquired from a position estimation unit and the destination position acquired from a memory unit. (Item 3) 3. The travel control system according to item 1 or 2, wherein the control unit controls the travel speed of the transport vehicle based on speed information acquired by a speed sensor of the transport vehicle. (Item 4) 3. The cruise control system according to item 1 or 2, wherein the control unit executes a process of calculating the distance d at predetermined regular intervals. (Item 5) 3. The driving control system according to item 1 or 2, wherein the control unit calculates an appropriate torque value of a motor that drives a driving wheel based on the driving speed v. (Item 6) 3. The cruise control system according to claim 1, wherein the current position is acquired by scanning a two-dimensional code installed on a road surface. (Item 7) A method for controlling travel of a transport vehicle, comprising: The control unit determines whether or not a distance d from the current position to the destination position is equal to or less than a predetermined value; A method for controlling the travel of a transport vehicle, characterized in that, when it is determined that the distance d is equal to or less than a predetermined value, the travel speed of the transport vehicle is controlled so that the relationship between the distance d, the travel speed v, and a constant k satisfies equation [A]. v = sqrt(2*k*d) [A] [Explanation of symbols]

[0071] 10 transport vehicle, 11 coupling section, 12 object position detection section, 13 drive wheel, 14 non-drive wheel, 16 guide line detection section, 17 magnetic sensor, 130 operating area, 131 guide line, 132 driving mode switching position, 210 communication section, 220 recording section, 230 detection section, 240 input section, 250 display section, 260 control section, 280 wheel drive section, 2000 cart, 2010 coupling receiving section, 3000 control unit, 4000 overall control device, 5000 input / output device, 6000 communication network, 7000 external system

Claims

1. A travel control system for a transport vehicle, determining whether a distance d from the current position to the destination position is equal to or smaller than a predetermined value; A transport vehicle driving control system characterized by having a control unit that controls the traveling speed of the transport vehicle when it is determined that the distance d is equal to or less than a predetermined value so that the relationship between the distance d, the traveling speed v, and the constant k satisfies equation [A]. v = sqrt(2*k*d) [A]

2. The cruise control system according to claim 1 , wherein the control unit executes a process of calculating the distance d based on a difference between the current position acquired from a position estimation unit and the destination position acquired from a storage unit.

3. The travel control system according to claim 1 , wherein the control unit controls a travel speed of the transport vehicle based on speed information acquired by a speed sensor of the transport vehicle.

4. The cruise control system according to claim 1 , wherein the control unit executes a process of calculating the distance d at predetermined regular intervals.

5. The driving control system according to claim 1 , wherein the control unit calculates an appropriate torque value of a motor that drives a driving wheel based on the driving speed v.

6. 3. The cruise control system according to claim 1, wherein the current position is acquired by scanning a two-dimensional code placed on a road surface.

7. A method for controlling travel of a transport vehicle, comprising: The control unit determines whether or not a distance d from the current position to the destination position is equal to or less than a predetermined value; A method for controlling the running of a transport vehicle, characterized in that, when it is determined that the distance d is equal to or less than a predetermined value, the running speed of the transport vehicle is controlled so that the relationship between the distance d, the running speed v, and a constant k satisfies equation [A]. v = sqrt(2*k*d) [A]

Images