Transport vehicles and traffic control systems

Abstract

To provide a transportation vehicle which is capable of stopping a vehicle body normally while reducing frequency of maintenance.SOLUTION: A transportation vehicle comprises a storage device which stores map information containing route slope and route limit speed and a vehicle control device which generates target speed on the basis of position, azimuth and travel speed of a vehicle body and the map information. The vehicle control device calculates limit speed for protection which increases according to time course from operation detection of a machine brake device on the basis of travel speed and route slope. The vehicle control device calculates a first distance capable of traveling if route limit speed after course of predetermined maintenance time is set as upper limit value of target speed and calculates a second distance capable of traveling if limit speed for protection is set as upper limit value of the target speed and functions smaller one among the limit speed for protection and the route limit speed as the upper limit value of the target speed if the first distance is smaller than the second distance and outputs maintenance request indication if the first distance is larger than the second distance.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to a transport vehicle and a traffic control system. [Background technology]

[0002] A series hybrid dump truck is known as a transport vehicle capable of autonomous driving, and is equipped with an engine, a generator driven by the engine, an electric motor driven by power from the generator, and wheels driven by the electric motor.

[0003] A series hybrid dump truck is equipped with an electric brake device that reduces the vehicle's speed by using regenerative torque generated by the electric motor as braking force, and a mechanical brake device that reduces the vehicle's speed by using friction as braking force. During normal autonomous driving, deceleration control is performed by the electric brake device. As a result, the mechanical brake device hardly wears out.

[0004] Mechanical brake devices are used to prevent collisions with obstacles and when a stop command is received. After use, mechanical brake devices lose braking performance due to heat generation and wear. For this reason, when a mechanical brake device is used, the transport vehicle's operation is stopped for maintenance of the mechanical brake device. During mechanical brake device maintenance, an investigation is conducted to determine whether braking performance meets the standard values, and if braking performance does not meet the standard values, repairs are carried out.

[0005] In this way, when a mechanical brake device is used in an autonomous transport vehicle, maintenance of the mechanical brake device reduces the operating time of the transport vehicle and reduces work efficiency. Furthermore, if maintenance of the mechanical brake device is performed every time the mechanical brake device is used, maintenance costs increase.

[0006] Patent Document 1 proposes a technology for a device that allows continuous operation without increasing maintenance costs when a mechanical brake device is used. Patent Document 1 discloses an elevator device that includes a car lifting system that uses a hoist to rotate a sheave to raise and lower a car connected to a rope hung on the sheave, an emergency brake that stops the rotation of the sheave through friction, and a system control unit that controls the car lifting system. The emergency brake is a mechanical brake device that stops the rotation of the brake disc by clamping it with a lining. The system control unit includes an emergency brake operation detection unit that detects the operation of the emergency brake, an emergency brake operation speed acquisition unit that acquires the speed of the car immediately before the emergency brake is activated, a lining wear amount calculation unit that calculates the wear amount of the emergency brake lining from the speed acquired by the emergency brake operation speed acquisition unit, and a car operation command unit that commands the operation of the car lifting system based on the calculated wear amount.

[0007] The technology described in Patent Document 1 acquires the speed just before the mechanical brake device is activated and calculates the amount of wear on the lining from the acquired speed. The amount of wear is calculated by adding the increase in wear due to the activation of the mechanical brake device to the amount of wear just before the mechanical brake device is activated. With the technology described in Patent Document 1, if the cumulative amount of wear reaches or exceeds the amount of wear at the elevator's travel limit, elevator operation is suspended. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-178495 Summary of the Invention [Problem to be solved by the invention]

[0009] Patent Document 1 describes a mechanical brake device for an elevator, but does not describe a mechanical brake device for a transport vehicle.

[0010] Transport vehicles such as dump trucks travel not only on flat ground but also on downhill and uphill slopes. The impact on the mechanical brake device differs when the mechanical brake device is activated on flat ground and when the mechanical brake device is activated on a slope. For this reason, there is a demand for a transport vehicle that can normally stop the vehicle body using the mechanical brake device not only on flat ground but also on downhill slopes, thereby reducing the frequency of maintenance.

[0011] An object of the present invention is to provide a transport vehicle that can reduce the frequency of maintenance of a mechanical brake device and that can stop the vehicle body normally using the mechanical brake device. [Means for solving the problem]

[0012] A transport vehicle according to one aspect of the present invention comprises a vehicle body, wheels provided on the vehicle body, a position sensor that acquires the position of the vehicle body, an orientation sensor that acquires the orientation of the vehicle body, a speed sensor that acquires the traveling speed of the vehicle body, a traveling drive device that includes a mechanical brake device and an electric brake device that apply braking force to the wheels and drives the wheels, a storage device that stores map information including a route shape, route gradient, and route speed limit of a traveling route of the vehicle body, and a vehicle control device that generates a control target including a target speed based on the position of the vehicle body, the orientation of the vehicle body, the traveling speed of the vehicle body, and the map information, and controls the traveling drive device so that the traveling speed of the vehicle body becomes the target speed. The vehicle control device calculates a protective speed limit for the mechanical brake device, which increases as time passes since detection of operation of the mechanical brake device, including a state in which the mechanical brake device is activated and then deactivated, based on the traveling speed acquired by the speed sensor and the route gradient included in the map information; calculates a first distance that can be traveled when the route speed limit is set as the upper limit of the target speed after a predetermined maintenance time has elapsed, within a predetermined elapsed time width since detection of operation of the mechanical brake device, including a state in which the mechanical brake device is activated and then deactivated; calculates a second distance that can be traveled when the protective speed limit is set as the upper limit of the target speed, within the predetermined elapsed time width since detection of operation of the mechanical brake device; if the first distance is smaller than the second distance, causes the vehicle body to travel with the smaller of the protective speed limit and the route speed limit as the upper limit of the target speed; and if the first distance is larger than the second distance, outputs a maintenance request instruction while maintaining the vehicle body in a stopped state. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a transport vehicle that can reduce the frequency of maintenance of a mechanical brake device and that can normally stop the vehicle body using the mechanical brake device. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a traffic control system. [Figure 2] FIG. 2 is a diagram showing the configuration of the transport vehicle. [Figure 3] FIG. 3 is a diagram illustrating a hardware configuration of the vehicle control device. [Figure 4] FIG. 4 is a functional block diagram of the vehicle control device according to the first embodiment, showing hardware connected to the vehicle control device and functions of the vehicle control device. [Figure 5] FIG. 5 is a diagram showing the travel route of a transport vehicle traveling within a transport path. [Figure 6] FIG. 6 is a diagram showing an example of a table of map information stored in the map and vehicle information storage unit according to the first embodiment. [Figure 7] FIG. 7 is a diagram showing an example of a table of vehicle information stored in the map and vehicle information storage unit according to the first embodiment. [Figure 8] FIG. 8 is a flowchart showing an example of the flow of a process for calculating the mechanical brake accumulated heat quantity Q executed by the mechanical brake heat quantity calculation unit. [Figure 9A] FIG. 9A is a graph showing an example of a change over time in the mechanical brake accumulated heat quantity Q. [Figure 9B] FIG. 9B is a graph showing an example of the change over time in the cumulative mechanical brake accumulated heat quantity U. [Figure 10] FIG. 10 is a flowchart showing an example of the flow of a speed limit calculation process executed by the speed limit calculation unit. [Figure 11] FIG. 11 is a flowchart showing an example of the flow of the target speed calculation process executed by the control target generating unit. [Figure 12] FIG. 12 is a time chart showing an example of how the speed limit Vc and the target speed Vt change over time. [Figure 13] FIG. 13 is a diagram showing an example of the difference in speed limit depending on whether maintenance has been performed or not. [Figure 14]FIG. 14 is a functional block diagram of a vehicle control device according to the second embodiment. [Figure 15] FIG. 15 is a diagram showing an example of a table of map information stored in the map and vehicle information storage unit according to the second embodiment. [Figure 16] FIG. 16 is a flowchart showing an example of the flow of the stored information updating process executed by the stored information updating device. [Figure 17] FIG. 17 is a graph showing an example of the change over time in the mechanical brake accumulated heat quantity Q depending on the weather. DETAILED DESCRIPTION OF THE INVENTION

[0015]

[0023] An embodiment of the present invention will be described with reference to the drawings. The following description shows specific examples of the contents of the present invention, and the present invention is not limited to these descriptions. Various changes and modifications can be made by those skilled in the art within the scope of the technical ideas disclosed in this specification. Furthermore, in all drawings used to explain the present embodiment, components having the same functions are designated by the same reference numerals, and repeated description thereof may be omitted.

[0016] First Embodiment FIG. 1 is a diagram showing a schematic configuration of a traffic control system 1 according to a first embodiment of the present invention. The traffic control system 1 shown in FIG. 1 includes at least one or more transport vehicles 20A, 20B that transport cargo such as earth and sand or ore at a work site such as a mine, and a control server 31 that controls traffic of the transport vehicles 20A, 20B. The transport vehicles 20A, 20B are also collectively referred to as transport vehicles 20. The transport vehicles 20 travel within a transport path 10 that is determined based on the shape of the work site. The transport vehicles 20 are unmanned vehicles that can travel autonomously without an operator on board. The control server 31 is located in a control station 30 that is provided near the work site or at a location far away from the work site. The control server 31 and the transport vehicles 20 exchange information with each other via a wireless communication line 39.

[0017] The transport vehicle 20 includes a vehicle body 21 on which a vessel (cargo bed) for carrying cargo is provided, and four wheels 22 provided on the vehicle body 21.

[0018] Fig. 2 is a diagram showing the configuration of the transport vehicle 20. As shown in Fig. 2, the transport vehicle 20 includes a travel drive device 120 that drives the wheels 22, and a vehicle control device 100 that controls the travel drive device 120. The travel drive device 120 includes an engine 121, a generator 122 driven by the engine 121, a power control device 123 that controls the power generated by the generator 122 and supplies it to the travel motors 124L, 124R, the travel motors 124L, 124R that drive the wheels 22, a steering device 125 that steers the wheels 22, and brake devices (electric brake devices 126 and mechanical brake devices 127) that apply braking force to the wheels 22.

[0019] The traveling motors 124L, 124R are electric motors for accelerating the vehicle body 21. The power supply to the traveling motors 124L, 124R is controlled by a power control device 123, and the rotation speed of the traveling motors 124L, 124R is controlled.

[0020] The power control device 123 is connected to the vehicle control device 100, and the vehicle control device 100 controls the power control device 123. The vehicle control device 100 controls the steering device 125 and the brake device via the power control device 123.

[0021] The steering device 125 includes a steering motor for changing the steering angle.

[0022] The brake devices include an electric brake device 126 and a mechanical brake device 127. The electric brake device 126 is a regenerative brake device that reduces the traveling speed by using regenerative torque generated by the traveling motors 124L, 124R, which are electric motors, as braking force. The mechanical brake device 127 is a friction-type mechanical brake device that can generate a braking force greater than that of the electric brake device 126. The mechanical brake device 127 is, for example, a disc brake device provided inside the wheel 22, and reduces the traveling speed by using friction force as braking force.

[0023] The electric brake device 126 is used to decelerate and stop the vehicle under normal circumstances. On the other hand, the mechanical brake device 127 is used to decelerate and stop the vehicle in an emergency. An emergency situation may occur when the vehicle control device 100 detects an obstacle around the transport vehicle 20 that may cause a collision, or when the control server 31 transmits an emergency stop signal to the transport vehicle 20. In an emergency, the electric brake device 126 and the mechanical brake device 127 operate in coordination, and a braking force is generated by the coordinated braking. When the brake device is activated in an emergency, a braking force is generated, the vehicle body 21 decelerates, the vehicle body 21 stops, and the stopped state of the vehicle body 21 is maintained thereafter. When the brake device is deactivated, the braking force disappears. With the brake device deactivated, the travel motors 124L, 124R are driven, and the vehicle body 21 starts traveling.

[0024] As shown in FIG. 3, the transport vehicle 20 also includes a sensor device 110 that detects various physical quantities, and a vehicle control device 100 that controls the travel drive device 120 based on signals from the sensor device 110, etc.

[0025] FIG. 3 is a diagram showing the hardware configuration of the vehicle control device 100. As shown in FIG. 3, the vehicle control device 100 is configured with a computer including a processing device 101 such as a central processing unit (CPU), a micro processing unit (MPU), or a digital signal processor (DSP), a non-volatile memory 102 such as a read-only memory (ROM), a flash memory, or a hard disk drive, a volatile memory 103 called a random access memory (RAM), an input interface 104, an output interface 105, and other peripheral circuits. These hardware components work together to run software and realize multiple functions. The vehicle control device 100 may be configured with one computer or multiple computers. The processing device 101 may be an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or the like.

[0026] The nonvolatile memory 102 is a nonvolatile storage medium from which information can be read and written. The nonvolatile memory 102 stores an OS (Operating System), control programs capable of executing various calculations, application programs, thresholds used in various calculations, databases, and the like. In other words, the nonvolatile memory 102 is a storage device (storage medium) from which a program that realizes the functions of this embodiment can be read. The processing device 101 is a device that loads the program stored in the nonvolatile memory 102 into the volatile memory 103 and executes the program, and performs predetermined calculations on data taken in from the input interface 104, the nonvolatile memory 102, and the volatile memory 103 in accordance with the program.

[0027] The input interface 104 converts signals input from the sensor device 110 and the like so that they can be calculated by the processing device 101. The output interface 105 generates an output signal according to the calculation result by the processing device 101, and outputs the signal to the traveling drive device 120, the notification device 130, and the like.

[0028] FIG. 4 is a functional block diagram of the vehicle control device 100, and shows the hardware connected to the vehicle control device 100 and the functions of the vehicle control device 100.

[0029] With reference to Fig. 4, the hardware connected to the vehicle control device 100 will be described. The vehicle control device 100 is connected to a sensor device 110, a travel drive device 120, a notification device 130, and a wireless communication device 131. The wireless communication device 131 is a communication device capable of wireless communication with a wireless base station constituting part of a wireless communication line 39, and has a communication interface including a communication antenna with a sensitivity band of, for example, the 2.1 GHz band. The wireless communication device 131 exchanges information with the control server 31 via the wireless communication line 39. The wireless communication line 131 is a wide area network such as a mobile phone communication network (mobile communication network) deployed by a mobile phone carrier or the like, or the Internet.

[0030] The notification device 130 notifies a maintenance request for the transport vehicle 20 in response to a maintenance request instruction output from the vehicle control device 100. The notification device 130 is, for example, an LED display attached to the exterior of the vehicle body 21, and when a maintenance request instruction is received, lights up an LED of a color corresponding to the maintenance request instruction. The notification device 130 may also be a sound output device (sounding device) that outputs a sound (horn sound) corresponding to the maintenance request instruction when a maintenance request instruction is received.

[0031] The sensor device 110 includes various sensors, such as a load sensor 111, a position sensor 112, a direction sensor 113, a speed sensor 114, a steering angle sensor 115, and a brake temperature sensor .

[0032] The load sensor 111 is used to acquire the load of the transport vehicle 20. The load sensor 111 detects, for example, the load acting on the suspension of the transport vehicle 20 or the pressure of hydraulic oil in a hydraulic cylinder (suspension cylinder), and calculates the load of the transport vehicle 20 based on the detection result.

[0033] The position sensor 112 is for acquiring the position of the vehicle body 21 (vehicle position). The orientation sensor 113 is for acquiring the orientation of the vehicle body 21 (the direction of the transfer vehicle 20). The position sensor 112 and the orientation sensor 113 include, for example, antennas for multiple GNSS (Global Navigation Satellite Systems) (hereinafter referred to as GNSS antennas), and a positioning calculation device that calculates the position of the vehicle body 21 expressed in actual coordinates in a three-dimensional space and the orientation angle, which is the angle from a reference orientation, based on satellite signals (GNSS radio waves) from multiple positioning satellites received by the GNSS antenna. The position of the vehicle body 21 is expressed, for example, by position coordinates of the vehicle body 21 in a geographic coordinate system (global coordinate system).

[0034] The position sensor 112 and the orientation sensor 113 may be configured with a single GNSS antenna and a positioning calculation device. In this case, the orientation sensor 113 calculates the orientation angle from the trajectory of the position of the vehicle body 21. The orientation sensor 113 may also include, for example, an IMU (Inertial Measurement Unit) and a calculation device that calculates the orientation angle from changes over time in angular acceleration information detected by the IMU.

[0035] The speed sensor 114 is for acquiring the traveling speed (vehicle speed) V of the vehicle body 21. The speed sensor 114 is, for example, a wheel speed sensor that detects the rotation speed of the wheels 22. Note that the speed sensor 114 may be a device that calculates the speed from the change over time in the position of the vehicle body 21 calculated by the position sensor 112.

[0036] The steering angle sensor 115 is used to acquire the steering angle of the transfer vehicle 20. The steering angle sensor 115 is, for example, an angle detection device such as an encoder attached to the steering device 125.

[0037] The brake temperature sensor 116 is for acquiring the temperature (hereinafter also referred to as the mechanical brake temperature) of the mechanical brake device 127 of the transport vehicle 20. The brake temperature sensor 116 measures, for example, the ambient temperature of the mechanical brake device 127 as the mechanical brake temperature.

[0038] The vehicle control device 100 controls the operation of the transfer vehicle 20. Fig. 5 is a diagram showing a travel route 11 of the transfer vehicle 20 traveling within the transfer path 10. As shown in Fig. 5, the vehicle control device 100 outputs a travel control command to the travel drive device 120 in order to perform autonomous travel along the travel route 11. The travel control command includes a brake operation amount, an accelerator operation amount, and a steering angle operation amount.

[0039] The travel route 11 is specified by a plurality of nodes 12. Information about the plurality of nodes 12 is stored in the map and vehicle information storage unit 157 (see FIG. 4 ), as will be described later. The travel route 11 is data indicating a curve within the conveyance path 10, and the nodes 12 are data indicating coordinates on the travel route 11. The vehicle control device 100 may cause the conveyance vehicle 20 to travel autonomously so as to minimize the deviation from the travel route 11, or may cause the conveyance vehicle 20 to travel autonomously so as to pass over the nodes 12. In this embodiment, the travel route 11 is a curve that passes through the center of the conveyance path 10. Furthermore, the nodes 12 are arranged at equal intervals on the travel route 11.

[0040] The vehicle control device 100 generates a control target including a target speed Vt based on the position of the vehicle body 21 acquired by the position sensor 112, the orientation of the vehicle body 21 acquired by the orientation sensor 113, the running speed V of the vehicle body 21 acquired by the speed sensor 114, and map information stored in the non-volatile memory 102, and controls the running drive device 120 so that the running speed V of the vehicle body 21 becomes the target speed Vt.

[0041] The functions of the vehicle control device 100 will be described in detail with reference to Fig. 4. As shown in Fig. 4, the vehicle control device 100 has functions as a mechanical brake operation detection unit 151, a speed limit generation unit 152, a control target generation unit 155, an autonomous driving control unit 156, and a map and vehicle information storage unit 157. The function of the map and vehicle information storage unit 157 is realized by the nonvolatile memory 102. The functions of the mechanical brake operation detection unit 151, the speed limit generation unit 152, the control target generation unit 155, and the autonomous driving control unit 156 are realized by the processing device 101 executing programs stored in the nonvolatile memory 102.

[0042] The map and vehicle information storage unit 157 has a map information storage area that stores map information in a table format, and a vehicle information storage area that stores vehicle information in a table format. Various thresholds are also stored in the map and vehicle information storage unit 157. The map information stored in the map and vehicle information storage unit 157 will be described with reference to Fig. 6. Fig. 6 is a diagram showing an example of a table of map information.

[0043] 6, the map information is information on a series of nodes that determine the route shape, route gradient, route speed limit, etc. of the travel route 11 (see FIG. 5) of the vehicle body 21 (host vehicle). Specifically, the map information defines a node ID, node coordinates (X, Y), route speed limit Va, route gradient θ, and road resistance Fr for each node.

[0044] The node ID is identification information of the node, and the node coordinates are position information of the node that determines the route shape of the travel route 11. The node coordinates are, for example, coordinates of a site coordinate system whose coordinate origin is set at the work site. The site coordinate system is a two-dimensional Cartesian coordinate system consisting of X and Y coordinates. Note that the node coordinates may also be coordinates of a geographic coordinate system. Coordinates in the site coordinate system and coordinates in the geographic coordinate system can be converted. The route speed limit Va is set as the upper limit of the travel speed at which the mechanical brake device 127 can normally stop the vehicle body 21, assuming that the mechanical brake device 127 is not in use. In addition, the route speed limit Va is set taking into account at least one of the curvature of the travel route 11 and the route gradient θ. Note that the curvature of the travel route 11 can be calculated as the reciprocal of the radius of a circle having a predetermined number of nodes 12 on its circumference. In addition, the curvature of the travel route 11 may be obtained as the reciprocal of the turning radius of the travel trajectory calculated from the azimuth angle of the vehicle body 21 or the change in the position of the vehicle body 21 over time when the transport vehicle 20 is travelling along the travel route 11 in advance, for example, through a manned travel test.

[0045] The route gradient θ is the inclination of the travel route 11 of the transport vehicle 20 with respect to the horizontal direction. The road resistance Fr is the force acting on the wheels 22 in the direction opposite to the traveling direction of the transport vehicle 20. Note that instead of the road resistance Fr, a resistance coefficient may be included in the map information. The resistance coefficient is a coefficient used to calculate the road resistance. The road resistance is calculated, for example, by multiplying this resistance coefficient by the load applied to the road surface from the wheels 22 (the load applied to the wheels 22 from the road surface).

[0046] The map and vehicle information storage unit 157 shown in Fig. 4 stores in advance map information for sections required for the transport vehicle 20 to travel. The map information stored in the map and vehicle information storage unit 157 is updated by information transmitted from the control server 31. The control server 31 includes a stored information update device 32 that updates information in the nonvolatile memory 102 provided in the transport vehicle 20. The stored information update device 32 transmits map update information that defines exclusive travel routes 11 to each transport vehicle 20 via the wireless communication device 35 so that multiple transport vehicles 20 do not come into contact with each other. The vehicle control device 100 updates the map information stored in the map and vehicle information storage unit 157 based on the map update information received via the wireless communication device 131.

[0047] Note that the map information is not limited to being updated. The predetermined map information may be maintained without being updated based on information from the control server 31. In this case, the control server 31 transmits a deceleration command or a stop command to a predetermined transport vehicle 20 based on the position of each transport vehicle 20 in order to avoid contact between the multiple transport vehicles 20.

[0048] The vehicle information stored in the map and vehicle information storage unit 157 will be described with reference to Fig. 7. Fig. 7 is a diagram showing an example of a table of vehicle information. As shown in Fig. 7, the vehicle information includes a mechanical brake accumulated heat quantity Q, an accumulated mechanical brake accumulated heat quantity U which is the accumulated value of the mechanical brake accumulated heat quantity Q, and an accumulated heat quantity calculation time T which is the time when the mechanical brake accumulated heat quantity Q and the accumulated mechanical brake accumulated heat quantity U are calculated, and is updated by the mechanical brake heat quantity calculation unit 153 described below.

[0049] 4 detects the operation of the mechanical brake device 127 when the rate of decrease of the traveling speed V acquired by the speed sensor 114 changes from a state below a predetermined decrease rate threshold to equal to or greater than the decrease rate threshold. Note that the mechanical brake operation detection unit 151 may also detect that the mechanical brake device 127 has been activated when the rate of increase of the brake temperature acquired by the brake temperature sensor 116 becomes equal to or greater than a predetermined threshold.

[0050] The speed limit generation unit 152 has a mechanical brake heat quantity calculation unit 153 and a speed limit calculation unit 154. When the mechanical brake operation detection unit 151 detects operation of the mechanical brake device 127, the mechanical brake heat quantity calculation unit 153 calculates the accumulated heat quantity Q of the mechanical brake device 127 (hereinafter also referred to as mechanical brake accumulated heat quantity) based on the traveling speed V of the vehicle body 21 acquired by the speed sensor 114. The mechanical brake accumulated heat quantity Q is the amount of heat accumulated in the mechanical brake device 127 due to operation of the mechanical brake device 127. The mechanical brake heat quantity calculation unit 153 associates the calculated mechanical brake accumulated heat quantity Q with an accumulated heat quantity calculation time T, which is the time when the mechanical brake accumulated heat quantity Q was calculated, and stores them in the map and vehicle information storage unit 157.

[0051] The mechanical brake heat quantity calculation unit 153 adds the calculated mechanical brake accumulated heat quantity Q (more specifically, the heat generation quantity Qa, which will be described later) to the accumulated mechanical brake accumulated heat quantity U stored in the map and vehicle information storage unit 157, and stores the result as a new accumulated mechanical brake accumulated heat quantity U in the map and vehicle information storage unit 157.

[0052] The mechanical brake heat quantity calculation unit 153 calculates the mechanical brake accumulated heat quantity Q accumulated by the operation of the mechanical brake device 127, and then calculates the heat dissipation quantity Qb from the mechanical brake device 127, and reduces the mechanical brake accumulated heat quantity Q by the calculated heat dissipation quantity Qb. At predetermined time intervals, the heat dissipation quantity Qb within the predetermined time is subtracted from the mechanical brake accumulated heat quantity Q, thereby calculating the mechanical brake accumulated heat quantity Q that decreases over time.

[0053] The speed limit calculation unit 154 calculates the protective speed limit Vb based on the mechanical brake accumulated heat quantity Q calculated by the mechanical brake heat quantity calculation unit 153. The protective speed limit Vb decreases as the mechanical brake accumulated heat quantity Q increases. The mechanical brake accumulated heat quantity Q increases when operation of the mechanical brake device 127 is detected, and then gradually decreases (see FIG. 9A). For this reason, the protective speed limit Vb has a characteristic of increasing as time passes from the detection of operation of the mechanical brake device 127, including the state when the mechanical brake device 127 is activated and then deactivated.

[0054] The control target generation unit 155 generates control targets including a target speed Vt and a target steering angle based on map information including the protective speed limit Vb calculated by the speed limit calculation unit 154, the route speed limit Va, and vehicle information. The autonomous driving control unit 156 generates a control command based on the control target generated by the control target generation unit 155, the traveling speed V acquired by the speed sensor 114, and the steering angle acquired by the steering angle sensor 115. The autonomous driving control unit 156 outputs the generated control command to the traveling drive device 120. As a result, each unit of the traveling drive device 120 is controlled, and the vehicle body 21 travels along the traveling route 11. Note that detailed functions of the mechanical brake heat amount calculation unit 153, the speed limit calculation unit 154, and the control target generation unit 155 will be described later.

[0055] The processing procedure for calculating the mechanical brake accumulated heat quantity Q will be described with reference to Fig. 8. Fig. 8 is a flowchart showing an example of the flow of the calculation processing for the mechanical brake accumulated heat quantity Q executed by the mechanical brake heat quantity calculation unit 153. The processing shown in the flowchart of Fig. 8 is started, for example, when the vehicle control device 100 is started, and is repeatedly executed at a predetermined control period (calculation period).

[0056] As shown in Fig. 8, in step S100, the mechanical brake heat quantity calculation unit 153 acquires map information and vehicle information from the map and vehicle information storage unit 157, and the process proceeds to step S105. In step S105, the mechanical brake heat quantity calculation unit 153 determines whether or not operation of the mechanical brake device 127 has been detected by the mechanical brake operation detection unit 151. If it is determined in step S105 that operation of the mechanical brake device 127 has been detected, the process proceeds to step S110. If it is determined in step S105 that operation of the mechanical brake device 127 has not been detected, the process proceeds to step S130.

[0057] In step S110, the mechanical brake heat quantity calculation unit 153 acquires the load weight W acquired by the load weight sensor 111 and the traveling speed V acquired by the speed sensor 114, and the process proceeds to step S115.

[0058] In step S115, the mechanical brake heat quantity calculation unit 153 calculates the amount of heat (hereinafter also referred to as the heat generation amount) Qa generated by the operation of the mechanical brake device 127. The mechanical brake heat quantity calculation unit 153 calculates the heat generation amount Qa based on the following formula (1), assuming that the kinetic energy of the transport vehicle 20 is converted into heat.

[0059]

number

[0060] M is the weight of the transport vehicle 20 when it is unladen (hereinafter also referred to as vehicle weight), and is stored in advance in the map and vehicle information storage unit 157. W is the load amount acquired in step S110, and V is the traveling speed acquired in step S110.

[0061] Once the heat generation amount Qa is calculated in step S115, the process proceeds to step S120. In step S120, the mechanical brake heat quantity calculation unit 153 adds the heat generation amount Qa to the mechanical brake accumulated heat quantity Q, and stores the result (Q+Qa) as the new mechanical brake accumulated heat quantity Q in the map and vehicle information storage unit 157. As a result, the mechanical brake accumulated heat quantity Q in the vehicle information in the map and vehicle information storage unit 157 is updated.

[0062] Furthermore, in step S120, the mechanical braking heat quantity calculation unit 153 adds the heat generation amount Qa to the cumulative mechanical braking accumulated heat quantity U, and stores the result (U+Qa) as the new cumulative mechanical braking accumulated heat quantity U in the map and vehicle information storage unit 157. As a result, the cumulative mechanical braking accumulated heat quantity U in the vehicle information in the map and vehicle information storage unit 157 is updated.

[0063] Furthermore, in step S120, the mechanical brake heat quantity calculation unit 153 updates this time as the accumulated heat quantity calculation time T in the vehicle information in the map and vehicle information storage unit 157. In this way, in step S120, the mechanical brake heat quantity calculation unit 153 updates the vehicle information (T, Q, U) in the map and vehicle information storage unit 157 based on the heat quantity Qa calculated in step S115.

[0064] In step S130, the mechanical brake heat quantity calculation unit 153 calculates the amount of heat Qb (hereinafter also referred to as heat radiation amount) released from the mechanical brake device 127. The mechanical brake device 127 generates heat when activated, and then radiations the heat at a predetermined rate over time. The mechanical brake heat quantity calculation unit 153 calculates the heat radiation amount Qb using the heat radiation amount qb per unit time determined in advance by experiments or the like, according to the following formula (2):

[0065]

number

[0066] qb is the amount of heat dissipation per unit time, and is stored in advance in the map and vehicle information storage unit 157. tb is the time elapsed since the previous calculation of the mechanical brake accumulated heat quantity Q. For example, tb is the time elapsed since the accumulated heat quantity calculation time T in the immediately previous control cycle, and corresponds to the control cycle in this flowchart.

[0067] Once the heat radiation amount Qb is calculated in step S130, the process proceeds to step S135. In step S135, the mechanical brake heat amount calculation unit 153 subtracts the heat radiation amount Qb from the mechanical brake accumulated heat amount Q, and stores the result (Q-Qb) as the new mechanical brake accumulated heat amount Q in the map and vehicle information storage unit 157. As a result, the mechanical brake accumulated heat amount Q in the vehicle information in the map and vehicle information storage unit 157 is updated.

[0068] Furthermore, in step S135, the mechanical brake heat quantity calculation unit 153 updates this time as the accumulated heat quantity calculation time T in the vehicle information in the map and vehicle information storage unit 157. In this way, in step S135, the mechanical brake heat quantity calculation unit 153 updates the vehicle information (T, Q) in the map and vehicle information storage unit 157 based on the heat release quantity Qb calculated in step S130.

[0069] When the update process in step S120 or step S135 is completed, the process shown in the flowchart of FIG. 8 ends.

[0070] 9A and 9B, an example of the change over time in the mechanical brake accumulated heat quantity Q and the cumulative mechanical brake accumulated heat quantity U calculated by the mechanical brake heat quantity calculation unit 153 will be described. In the graph of Fig. 9A, the horizontal axis represents time, and the vertical axis represents the mechanical brake accumulated heat quantity Q. In the graph of Fig. 9B, the horizontal axis represents time, and the vertical axis represents the cumulative mechanical brake accumulated heat quantity U.

[0071] As shown in Figures 9A and 9B, at time ta1, when the mechanical brake device 127 is activated, the mechanical brake accumulated heat quantity Q and the cumulative mechanical brake accumulated heat quantity U increase by the heat generation amount Qa. Thereafter, the mechanical brake accumulated heat quantity Q gradually decreases due to heat dissipation. At time ta2, when the mechanical brake device 127 is activated again, the mechanical brake accumulated heat quantity Q and the cumulative mechanical brake accumulated heat quantity U increase by the heat generation amount Qa. Thereafter, the mechanical brake accumulated heat quantity Q gradually decreases due to heat dissipation.

[0072] The processing procedure for calculating the speed limit by the speed limit calculation unit 154 will be described with reference to Fig. 10. Fig. 10 is a flowchart showing an example of the flow of the speed limit calculation processing executed by the speed limit calculation unit 154. The processing shown in the flowchart in Fig. 10 is started, for example, when the vehicle control device 100 is started, and is repeatedly executed at a predetermined control period (calculation period).

[0073] As shown in FIG. 10, in step S140, the speed limit calculation unit 154 acquires map information and vehicle information from the map and vehicle information storage unit 157, and the process proceeds to step S143.

[0074] In step S143, the speed limit calculation unit 154 determines whether the mechanical brake accumulated heat quantity Q included in the vehicle information acquired in step S140 is greater than the mechanical brake activation limit heat quantity Qmax. The mechanical brake activation limit heat quantity Qmax is a threshold value determined based on the limit value at which the mechanical brake device 127 is not damaged during operation, and is stored in advance in the map and vehicle information storage unit 157. If it is determined in step S143 that the mechanical brake accumulated heat quantity Q is equal to or less than the mechanical brake activation limit heat quantity Qmax, the process proceeds to step S146. If it is determined in step S143 that the mechanical brake accumulated heat quantity Q is greater than the mechanical brake activation limit heat quantity Qmax, the process proceeds to step S170.

[0075] In step S146, the speed limit calculation unit 154 determines whether the cumulative mechanical brake accumulated heat quantity U included in the vehicle information acquired in step S140 is greater than the cumulative mechanical brake activation limit heat quantity Umax. The cumulative mechanical brake activation limit heat quantity Umax is a threshold value determined based on the limit value at which the mechanical brake device 127 is not damaged during operation, and is stored in advance in the map / vehicle information storage unit 157. If it is determined in step S146 that the cumulative mechanical brake accumulated heat quantity U is equal to or less than the cumulative mechanical brake activation limit heat quantity Umax, the process proceeds to step S149. If it is determined in step S146 that the cumulative mechanical brake accumulated heat quantity U is greater than the cumulative mechanical brake activation limit heat quantity Umax, the process proceeds to step S170.

[0076] In step S149, the speed limit calculation unit 154 acquires the position (current position) P of the vehicle body 21 from the position sensor 112, the traveling speed V from the speed sensor 114, and the load weight W from the load weight sensor 111, and the process proceeds to step S152.

[0077] In step S152, the speed limit calculation unit 154 acquires the route gradient θ and road surface resistance Fr of the position (current position) P of the vehicle body 21 from the map and vehicle information storage unit 157, and calculates the braking distance L when the mechanical brake device 127 is activated using the following equation (3). The braking distance L is the distance that the transport vehicle 20 travels from when the mechanical brake device 127 is activated until it comes to a stop (V=0).

[0078]

number

[0079] R is the deceleration force (braking force) that can be exerted by the mechanical brake device 127, and is a force in the direction opposite to the traveling direction of the vehicle body 21. The deceleration force R can be determined based on the measurement results of a deceleration force that can be exerted on flat ground that is measured in advance. In this case, the deceleration force R is a constant value that is stored in advance in the map and vehicle information storage unit 157. Note that the deceleration force R may be corrected based on the mechanical brake temperature acquired by the brake temperature sensor 116. In this case, the corrected deceleration force R is calculated by reducing the reference value of the deceleration force (deceleration force before correction) stored in the map and vehicle information storage unit 157 in inverse proportion to the mechanical brake temperature.

[0080] G is a thrust force (gradient resistance) generated by the route gradient θ. Note that G is a force in the direction of travel if the road is downhill, but a force in the opposite direction to the direction of travel if the road is uphill. The thrust force G is calculated from the route gradient θ, the vehicle weight M, the load W, and the gravitational acceleration g (G = (M + W) × g × sin θ), assuming that the route gradient θ of the current position continues ahead of the transport vehicle 20. Note that the speed limit calculation unit 154 may calculate the thrust force G(l), which changes depending on the travel distance l, using the route gradient θ(l) acquired from map information based on the travel distance l.

[0081] A fixed value is set in advance for each node for road resistance Fr based on the soil quality of the mine, etc. M is the vehicle weight, which is stored in advance in the map and vehicle information storage unit 157. W is the load weight, which is acquired by the load weight sensor 111.

[0082] When the braking distance L when the mechanical brake device 127 is activated is calculated in step S152, the process proceeds to step S155. In step S155, the speed limit calculation unit 154 calculates the amount of change ΔN in potential energy. The speed limit calculation unit 154 calculates the elevation difference h from the current position to the predicted stop position based on the braking distance L from the start of activation of the mechanical brake device 127 to the stop and the route gradient θ of the map information. The elevation difference h is calculated from the route gradient θ and the braking distance L (h = L × sin θ) assuming that the route gradient θ of the current position continues ahead of the transfer vehicle 20. Note that the speed limit calculation unit 154 may calculate the elevation difference h using the route gradient θ(l) according to the moving distance l from the current position to the predicted stop position. The speed limit calculation unit 154 calculates the amount of change in potential energy ΔN based on the calculated altitude difference h, the vehicle weight M, the load W, and the gravitational acceleration g (ΔN=(M+W)×g×h).

[0083] Once the change in potential energy ΔN is calculated in step S155, the process proceeds to step S158. In step S158, the speed limit calculation unit 154 calculates an allowable kinetic energy Ea at which the mechanical brake device 127 can operate normally until the vehicle comes to a stop. The speed limit calculation unit 154 calculates a first value Q1 (=Qmax-ΔN-Q) by subtracting the change in potential energy ΔN and the mechanical brake accumulated heat quantity Q from the mechanical brake activation limit heat quantity Qmax, and a second value Q2 (=Umax-ΔN-U) by subtracting the change in potential energy ΔN and the accumulated mechanical brake accumulated heat quantity U from the accumulated mechanical brake activation limit heat quantity Umax. The speed limit calculation unit 154 compares the first value Q1 with the second value Q2 and calculates the smaller of the first value Q1 and the second value Q2 as the allowable kinetic energy Ea (Ea=Min(Q1, Q2)).

[0084] Once the allowable kinetic energy Ea is calculated in step S158, the process proceeds to step S161. In step S161, the speed limit calculation unit 154 calculates a speed at which the mechanical brake device 127 can operate normally until the vehicle stops as a protective speed limit (speed at which the vehicle can stop) Vb, based on the allowable kinetic energy Ea, the vehicle weight M, and the load W. The protective speed limit Vb is calculated using the following equation (4).

[0085]

number

[0086] Once the protection speed limit Vb is calculated in step S161, the process proceeds to step S164. In step S164, the speed limit calculation unit 154 compares the route speed limit Va included in the map information acquired in step S140 with the protection speed limit Vb calculated in step S158, and sets the smaller one as the speed limit Vc.

[0087] If an affirmative decision is made in step S143 or step S146, the process proceeds to step S170. In step S170, the speed limit calculation unit 154 sets the speed limit Vc to 0 (Vc=0), and the process proceeds to step S175.

[0088] In step S175, the speed limit calculation unit 154 outputs a maintenance request instruction to the notification device 130. The notification device 130 notifies the maintenance request. When the process of step S164 or step S175 ends, the process shown in the flowchart in FIG. 10 ends.

[0089] When the notification device 130 notifies a maintenance request, a maintenance worker performs maintenance on the mechanical brake device 127. In the maintenance of the mechanical brake device 127, it is checked whether the braking performance satisfies a standard value, and if the braking performance does not satisfy the standard value, repairs are performed.

[0090] When the operation of the mechanical brake device 127 is detected, the speed limit generator 152 calculates in advance the speed limit Vb for nodes 12 within a predetermined range on the travel route 11 ahead of the vehicle body 21 from the predicted stopping position. The predetermined range includes a range in which travel is possible within a predetermined elapsed time width, which will be described later.

[0091] 11 to 13, the contents of the calculation process of the target speed Vt by the control target generator 155 will be described. The calculation process procedure of the target speed by the control target generator 155 will be described with reference to Fig. 11. Fig. 11 is a flowchart showing an example of the flow of the target speed calculation process executed by the control target generator 155. The process shown in the flowchart in Fig. 11 is started, for example, when the vehicle control device 100 is started, and is repeatedly executed at a predetermined control period (calculation period).

[0092] 11, in step S180, the control target generator 155 determines whether or not operation of the mechanical brake device 127 has been detected by the mechanical brake operation detector 151. If it is determined in step S180 that operation of the mechanical brake device 127 has not been detected, the process proceeds to step S185.

[0093] In step S185, the control target generator 155 calculates the target speed Vt based on the speed limit Vc. If the speed limit Vc increases, the control target generator 155 calculates the target speed Vt to follow the increase in the speed limit Vc. If the speed limit Vc decreases, the control target generator 155 calculates the target speed Vt so that the actual traveling speed V does not exceed the speed limit Vc.

[0094] FIG. 12 is a time chart showing an example of time change of the speed limit Vc and the target speed Vt. In the time chart of FIG. 12, the horizontal axis represents time, and the vertical axis represents the speed limit Vc and the target speed Vt. For example, as shown in FIG. 12, when the speed limit Vc (= Va) set at a forward position (node) a predetermined distance away from the current position of the transfer vehicle 20 is smaller than the current traveling speed V (= Vc1), the control target generation unit 155 calculates the target speed Vt so that deceleration starts in advance. The target speed Vt is calculated based on the deceleration that the electric brake device 126 can exert. The deceleration is the amount of change (slope) of the speed per unit time.

[0095] The control target generator 155 calculates the deceleration when only the electric brake device 126 is used, based on the route gradient θ included in the map information and the traveling speed V acquired by the speed sensor 114.

[0096] 12, the target speed Vt starts to decrease from time tb1, which is before time tb2 when the speed limit Vc starts to decrease from Vc1 to Vc2. In this way, the control target generator 155 decreases the target speed Vt based on the calculated deceleration at a position closer to the vehicle body 21 than the position where the route speed limit Va decreases. This makes it possible to prevent the traveling speed V from exceeding the speed limit Vc.

[0097] The speed limit Vc is set to Vc2 at time tb3. The deceleration corresponds to Vc2-Vc1 / (tb3-tb2). Thereafter, when the activation condition for the mechanical brake device 127 is satisfied at time tb4, the speed limit Vc and the target speed Vt are set to 0 (zero), and the mechanical brake device 127 and the electric brake device 126 are activated. As a result, the actual traveling speed V (not shown) suddenly decreases, and the vehicle body 21 stops (V=0). The activation condition for the mechanical brake device 127 is satisfied, for example, when an obstacle that may cause a collision is detected around the transfer vehicle 20. The activation condition for the mechanical brake device 127 is also satisfied when an emergency stop signal is transmitted from the control server 31 to the transfer vehicle 20. At time tb5, when a travel start signal for the transfer vehicle 20 is transmitted from the control server 31, the transfer vehicle 20 starts traveling. Since the target speed Vt increases in response to an increase in the speed limit Vc, the traveling speed V of the transfer vehicle 20 gradually increases.

[0098] 11, if it is determined in step S180 that operation of the mechanical braking device 127 has been detected, the process proceeds to step S190. In step S190, the control target generator 155 calculates a first distance La that can be traveled when the route speed limit Va is set as the upper limit of the target speed after a predetermined maintenance time tm has elapsed, within a predetermined elapsed time range Δt from when operation of the mechanical braking device 127 was detected. Note that the predetermined elapsed time range Δt is an elapsed time range that includes a state in which the mechanical braking device 127 was activated and then deactivated. Once the first distance La has been calculated, the process proceeds to step S192.

[0099] In step S192, the control target generator 155 calculates a second distance Lb that can be traveled when the protective speed limit Vb is set as the upper limit of the target speed Vt within the predetermined elapsed time period Δt after the operation of the mechanical brake device 127 is detected. Once the second distance Lb is calculated, the process proceeds to step S194.

[0100] Fig. 13 is a diagram showing an example of the difference in speed limit depending on whether maintenance has been performed. As shown in Fig. 13, when the activation condition for the mechanical brake device 127 is met at time tc1, the speed limit Vc is set to 0 (zero), and the mechanical brake device 127 and the electric brake device 126 are activated. As a result, the actual traveling speed V (not shown) suddenly decreases, and the car body 21 stops at time tc2 (V=0).

[0101] The control target generation unit 155 calculates a first distance La (corresponding to the area of ​​the hatched area in the figure) which is the travel distance when traveling at the route speed limit Va from time tc3 after the maintenance time tm has elapsed since the vehicle body 21 stopped at time tc2 due to the activation of the mechanical braking device 127, within a predetermined elapsed time range Δt after the detection of the activation of the mechanical braking device 127. Note that FIG. 13 shows an example in which the route speed limit Va increases continuously from 0 (zero) at a predetermined slope, but the route speed limit Va may also increase discontinuously from 0. The maintenance time tm is determined in advance through experiments or the like and stored in the map and vehicle information storage unit 157. In the example shown in FIG. 13, the start of the maintenance time tm is set to the stopping time tc2, but the start of the maintenance time tm may also be set to the time tc1 when the activation of the mechanical braking device 127 is detected.

[0102] The control target generation unit 155 calculates a second distance Lb (corresponding to the area of ​​the hatched area in the figure), which is the travel distance when traveling at the protective speed limit Vb within a predetermined elapsed time Δt after detecting the operation of the mechanical brake device 127. Note that it may be assumed that the transport vehicle 20 stops at time tc2 and immediately resumes traveling, or that it resumes traveling after a predetermined time has elapsed since time tc2. The mechanical brake accumulated heat quantity Q gradually decreases over time after the operation of the mechanical brake device 127. Therefore, the protective speed limit Vb gradually increases over time.

[0103] The predetermined elapsed time width Δt is preferably set to a value equal to or greater than the time from time tc1 when the operation of the mechanical brake device 127 is detected to time tc4 when the protective speed limit Vb reaches the route speed limit Va. The predetermined elapsed time width (fixed value) Δt is determined in advance through experiments or the like, and is stored in the map and vehicle information storage unit 157.

[0104] The predetermined elapsed time width Δt is not limited to a fixed value. For example, the control target generating unit 155 may calculate the predetermined elapsed time width Δt based on the traveling speed V at the time when the mechanical brake device 127 starts to operate. In this case, a data table associating the traveling speed V with the elapsed time width Δt is stored in the map and vehicle information storage unit 157. This data table defines a characteristic in which the elapsed time width Δt increases as the traveling speed V increases.

[0105] 11, in step S194, the control target generator 155 determines whether the first distance La calculated in step S190 is equal to or greater than the second distance Lb calculated in step S192. If it is determined in step S194 that the first distance La is equal to or greater than the second distance Lb, the process proceeds to step S196. If it is determined in step S194 that the first distance La is smaller than the second distance Lb, the process proceeds to step S185.

[0106] In step S196, the control target generator 155 sets the target speed Vt to 0 (Vt=0), and the process proceeds to step S198. In step S198, the control target generator 155 outputs a maintenance request instruction to the notification device 130. The notification device 130 notifies the maintenance request. When the process of step S185 or step S198 ends, the process shown in the flowchart in FIG. 11 ends.

[0107] If the distance that can be traveled by the predetermined time tc4 when traveling is resumed after maintenance of the mechanical brake device 127 (first distance La) is greater than the distance that can be traveled by the predetermined time tc4 when traveling is resumed without maintenance of the mechanical brake device 127 (second distance Lb), performing maintenance of the mechanical brake device 127 will result in a higher average speed and improved productivity. Therefore, in this embodiment, if the first distance La is greater than the second distance Lb, the vehicle control device 100 outputs a maintenance request instruction to the notification device 130 while maintaining the stopped state of the vehicle body 21.

[0108] When the first distance La is smaller than the second distance Lb, the average speed is higher and productivity is improved by not performing maintenance on the mechanical brake device 127. Therefore, in this embodiment, when the first distance La is smaller than the second distance Lb, the vehicle control device 100 causes the vehicle body 21 to travel with the smaller of the protective speed limit Vb and the route speed limit Va as the upper limit value of the target speed Vt.

[0109] As described above, the vehicle control device 100 according to this embodiment calculates the mechanical brake accumulated heat quantity Q when braking performance of the mechanical brake device 127 deteriorates due to heat generation and wear during use. The vehicle control device 100 calculates the kinetic energy Ea (allowable kinetic energy) required to stop the transport vehicle 20 while the mechanical brake device 127 is operating normally, based on the potential energy that increases or decreases when the transport vehicle 20 is stopped, calculated from the road surface resistance Fr ahead of the transport vehicle 20, the route gradient θ, and the load W, the mechanical brake accumulated heat quantity Q, and the mechanical brake activation limit heat quantity Qmax. The vehicle control device 100 calculates the protective speed limit Vb based on the allowable kinetic energy Ea. By continuing operation of the transport vehicle 20 at or below the protective speed limit Vb, the vehicle control device 100 can prevent a reduction in operating time due to maintenance of the mechanical brake device 127. Furthermore, if the travel distance after a predetermined time based on the route speed limit Va after maintenance is performed is longer than the travel distance after a predetermined time based on the protective speed limit Vb, the vehicle control device 100 requests maintenance, thereby improving the average speed and preventing a decrease in productivity.

[0110] According to the above-described embodiment, the following advantageous effects are achieved.

[0111] (1) The transport vehicle 20 includes a body 21, wheels 22 provided on the body 21, a position sensor 112 that acquires the position of the body 21, a direction sensor 113 that acquires the direction of the body 21, and a speed sensor 114 that acquires the traveling speed (vehicle speed) V of the body 21. The transport vehicle 20 includes a mechanical brake device 127 and an electric brake device 126 that apply braking force to the wheels 22, and is equipped with a travel drive device 120 that drives the wheels 22. The transport vehicle 20 includes a non-volatile memory (storage device) 102 that stores map information including node coordinates that represent the route shape of the travel route 11 of the body 21, a route gradient θ, and a route speed limit Va. The transport vehicle 20 is equipped with a vehicle control device 100 that generates a control target including a target speed Vt based on the position of the vehicle body 21, the orientation of the vehicle body 21, the running speed V of the vehicle body 21, and map information, and controls the running drive device 120 so that the running speed V of the vehicle body 21 becomes the target speed Vt.

[0112] The vehicle control device 100 calculates a protective speed limit Vb for the mechanical braking device 127, which increases as time passes since detection of operation of the mechanical braking device 127, including states in which the mechanical braking device 127 is activated and then deactivated, based on the traveling speed V acquired by the speed sensor 114 and the route gradient θ included in the map information. The vehicle control device 100 calculates a first distance La that can be traveled when the route speed limit Va is set as the upper limit of the target speed Vt after a predetermined maintenance time tm has elapsed, within a predetermined elapsed time Δt from detection of operation of the mechanical braking device 127, including states in which the mechanical braking device 127 is activated and then deactivated. The vehicle control device 100 calculates a second distance Lb that can be traveled when the protective speed limit Vb is set as the upper limit of the target speed Vt, within the predetermined elapsed time Δt from detection of operation of the mechanical braking device 127. When the first distance La is smaller than the second distance Lb, the vehicle control device 100 causes the vehicle body 21 to travel with the smaller of the protective speed limit Vb and the route speed limit Va as the upper limit value of the target speed Vt. On the other hand, when the first distance La is larger than the second distance Lb, the vehicle control device 100 outputs a maintenance request instruction while maintaining the vehicle body 21 in a stopped state.

[0113] In this configuration, when the first distance La is smaller than the second distance Lb, the vehicle continues traveling without performing maintenance, thereby preventing downtime due to maintenance (maintenance time tm). In this case, the protective speed limit Vb, which is the upper limit of the target speed Vt, has a characteristic that increases as time passes after the detection of the operation of the mechanical brake device 127. With this characteristic, the traveling speed V is kept low when the temperature is high just after the mechanical brake device 127 has been activated, so that even if the mechanical brake device 127 is activated again while traveling, the vehicle body 21 can be stopped normally.

[0114] Furthermore, when the first distance La is greater than the second distance Lb, the vehicle control device 100 outputs a maintenance request instruction to the notification device 130. This allows maintenance to be performed at a stage before an abnormality occurs in the mechanical brake device 127.

[0115] As described above, according to this embodiment, it is possible to reduce the frequency of maintenance of the mechanical brake device 127, and it is possible to provide a transport vehicle 20 that can stop the vehicle body 21 normally using the mechanical brake device 127.

[0116] (2) The transport vehicle 20 is equipped with a load sensor 111 that acquires the load weight of the transport vehicle 20. The vehicle control device 100 calculates the protective speed limit Vb by taking into account the load weight W acquired by the load sensor 111 (see FIGS. 8 and 10). With this configuration, an appropriate protective speed limit Vb can be calculated in accordance with changes in the load weight W.

[0117] (3) The map information includes the road resistance Fr of the travel route 11. The vehicle control device 100 calculates the protective speed limit Vb taking into account the road resistance Fr (see FIG. 10). With this configuration, it is possible to calculate an appropriate protective speed limit Vb in accordance with changes in the road resistance Fr.

[0118] (4) The transport vehicle 20 is equipped with an alarm device 130 that issues an alarm of a maintenance request for the transport vehicle 20 in response to a maintenance request instruction. When the vehicle control device 100 detects the operation of the mechanical brake device 127, it calculates a mechanical brake accumulated heat quantity Q, which is the amount of heat accumulated in the mechanical brake device 127 due to the operation of the mechanical brake device 127. When the calculated mechanical brake accumulated heat quantity Q exceeds a predetermined value (mechanical brake operation limit heat quantity) Qmax, the vehicle control device 100 outputs a maintenance request instruction to the alarm device 130 (Yes in S143, S170, S175 in FIG. 10 ).

[0119] Furthermore, when the vehicle control device 100 detects the operation of the mechanical brake device 127, it calculates a cumulative mechanical brake accumulated heat amount U, which is the cumulative value of the heat amount accumulated in the mechanical brake device 127 due to the operation of the mechanical brake device 127 (cumulative value of the heat generation amount Qa). When the calculated cumulative mechanical brake accumulated heat amount U exceeds a predetermined value (cumulative mechanical brake operation limit heat amount) Umax, the vehicle control device 100 outputs a maintenance request instruction to the notification device 130 (Yes in S146, S170, S175 in FIG. 10).

[0120] According to this configuration, after the vehicle has stopped due to the operation of the mechanical brake device 127, it is possible to prevent the vehicle from starting to travel while the mechanical brake device 127 is close to its operating limit.

[0121] Second Embodiment A traffic control system 1A according to a second embodiment of the present invention will be described with reference to Figures 14 to 17. Note that components that are the same as or equivalent to those described in the first embodiment are given the same reference numerals, and differences will be mainly described.

[0122] 14 is a functional block diagram of a vehicle control device 100A according to the second embodiment. As shown in FIG. 14, the traffic control system 1A according to the second embodiment includes two or more transport vehicles 20 and a control server 31A that performs traffic control of the transport vehicles 20.

[0123] In the first embodiment, an example was described in which the road resistance Fr of each node is a fixed value. In contrast, the vehicle control device 100A according to the second embodiment updates the road resistance Fr included in the map information based on an actual measurement value. For example, the vehicle control device 100A estimates the road resistance Fr from the ratio between the wheel speed and the traveling speed V during traveling, and updates the road resistance Fr included in the map information.

[0124] The method for updating the road resistance Fr is not limited to this. For example, the vehicle control device 100A calculates the road resistance Fr based on the traveling speed V acquired by the speed sensor 114 when operation of the mechanical braking device 127 is detected, the position P (brake application position) of the vehicle body 21 acquired by the position sensor 112 when operation of the mechanical braking device 127 is detected, the position P (stop position) of the vehicle body 21 acquired by the position sensor 112 when the vehicle body 21 is stopped by operation of the mechanical braking device 127, and the route gradient θ of the traveling route 11 from the brake application position to the stop position. Then, the vehicle control device 100A updates the road resistance Fr in the map information using the calculated road resistance Fr. The vehicle control device 100A determines that the vehicle body 21 has stopped when the traveling speed V acquired by the speed sensor 114 becomes 0 (zero).

[0125] This configuration improves the accuracy of the road surface resistance Fr in the map information, thereby improving the accuracy of the protective speed limit Vb.

[0126] When the vehicle control device 100A detects the operation of the mechanical brake device 127, it calculates the mechanical brake accumulated heat quantity Q based on the traveling speed V acquired by the speed sensor 114. The vehicle control device 100A transmits the calculated mechanical brake accumulated heat quantity Q and the accumulated heat quantity calculation time T to the control server 31A.

[0127] The transport vehicle 20 transmits a travel record (including map information and vehicle information) that is information recorded during travel to the control server 31A. The control server 31A collects the travel records of a plurality of transport vehicles 20. The control server 31A aggregates the road surface resistance Fr acquired from a plurality of transport vehicles 20 and updates the map information of each transport vehicle 20. This allows the transport vehicle 20A to acquire the latest road surface resistance Fr of a node on the travel route 11 that the transport vehicle 20A has not traveled on but the transport vehicle 20B has traveled on, for example.

[0128] The control server 31A also acquires weather information and determines the amount of heat dissipation per unit time qb based on the acquired weather information. The control server 31A acquires the mechanical brake accumulated heat Q calculated by the vehicle control device 100A of a predetermined transport vehicle 20A and the time T at which the mechanical brake accumulated heat Q was calculated (accumulated heat calculation time). The control server 31A calculates the elapsed time ΔT from the accumulated heat calculation time T, and calculates a corrected accumulated heat Q' by correcting the accumulated heat Q of the mechanical brake device 127 based on the elapsed time ΔT and the amount of heat dissipation per unit time qb. The control server 31A transmits the corrected accumulated heat Q' to the vehicle control device 100A of the transport vehicle 20A. The vehicle control device 100A of the transport vehicle 20A calculates the protective speed limit Vb based on the corrected accumulated heat Q'. That is, the vehicle control device 100A replaces the mechanical brake accumulated heat quantity Q included in the vehicle information stored in the map and vehicle information storage unit 157A with the corrected accumulated heat quantity Q' to calculate the protective speed limit Vb.

[0129] According to the second embodiment, the vehicle control device 100A can calculate the protective speed limit Vb with higher accuracy by using the road resistance Fr and the corrected accumulated heat quantity Q' acquired from the control server 31A. The traffic control system 1A according to the second embodiment will be described in detail below.

[0130] The control server 31A includes a storage information update device 32A and a weather information acquisition device 34A. The hardware configurations of the storage information update device 32A and the weather information acquisition device 34A are the same as the hardware configuration of the vehicle control device 100 shown in FIG. 3. That is, the storage information update device 32A and the weather information acquisition device 34A are each configured as a computer equipped with a processing device, a non-volatile memory (storage device), a volatile memory (storage device), an input / output interface, and other peripheral circuits. The storage information update device 32A and the weather information acquisition device 34A each perform program calculations, read and write information to a working area in the volatile memory, and temporarily store programs to perform predetermined functions. Note that the storage information update device 32A and the weather information acquisition device 34A may be configured as a single computer.

[0131] Fig. 15 is a diagram showing an example of a table of map information stored in the map and vehicle information storage unit 157A according to the second embodiment. As shown in Fig. 15, the map information stored in the map and vehicle information storage unit 157A includes the road resistance update time t in addition to the information described in the first embodiment.

[0132] 14 acquires weather information including the weather and temperature, and outputs it to the stored information update device 32A. The stored information update device 32A updates the road surface resistance Fr in the map information, and the mechanical brake accumulated heat Q and accumulated heat calculation time T in the vehicle information.

[0133] The processing procedure of the memory information update device 32A will be described with reference to Fig. 16. Fig. 16 is a flowchart showing an example of the flow of memory information update processing executed by the memory information update device 32A. The memory information update device 32A repeatedly executes the processing shown in the flowchart of Fig. 16 at a predetermined control period.

[0134] As shown in FIG. 16, in step S205, the stored information update device 32A acquires weather information from the weather information acquisition device 34A, and the process proceeds to step S210.

[0135] In step S210, the stored information update device 32A sets a variable k to 1, and the process proceeds to step S215. The variable k is a number for identifying a predetermined transfer vehicle 20 from among the multiple transfer vehicles 20.

[0136] In step S215, the storage information update device 32A acquires the mechanical brake accumulated heat Q and accumulated heat calculation time T contained in the vehicle information from the map and vehicle information storage unit 157A via the wireless communication device 35 from the kth transport vehicle 20, and proceeds to step S220.

[0137] In step S220, the stored information updating device 32A sets the amount of heat dissipation per unit time qb based on the weather information, and the process proceeds to step S225.

[0138] The memory information update device 32A has a weather table in which, for example, weather information (sunny, cloudy) is associated with the heat dissipation amount qb. The weather table defines a sunny heat dissipation amount qb1, which is the heat dissipation amount qb when it is sunny, and a cloudy heat dissipation amount qb2, which is the heat dissipation amount qb when it is cloudy. The memory information update device 32A refers to the weather table and sets the heat dissipation amount qb based on the weather included in the weather information acquired in step S205.

[0139] The amount of heat dissipation per unit time qb may be set to a value corresponding to the temperature. In this case, the stored information update device 32A compares the temperature with a predetermined temperature threshold and sets the amount of heat dissipation qb according to the comparison result.

[0140] FIG. 17 is a graph showing an example of how the mechanical brake accumulated heat quantity Q changes over time depending on the weather. As shown in FIG. 17, when the weather is sunny or the temperature is high, the temperature difference between the mechanical brake device 127 and the outside air is small, and it takes time for the mechanical brake accumulated heat quantity Q to decrease. For this reason, when the weather is sunny or the temperature is high, a smaller value of the heat release quantity qb is set compared to when it is cloudy or the temperature is low. When it is cloudy or the temperature is low, the temperature difference between the mechanical brake device 127 and the outside air is large, and the mechanical brake accumulated heat quantity Q decreases more quickly compared to when it is sunny or the temperature is high. For this reason, when it is cloudy or the temperature is low, a larger value of the heat release quantity qb is set compared to when it is sunny or the temperature is high.

[0141] As shown in FIG. 16, in step S225, the stored information updating device 32A calculates the elapsed time td from the accumulated heat amount calculation time T to the current time, and proceeds to step S230.

[0142] In step S230, the memory information update device 32A calculates the mechanical brake accumulated heat quantity Q at the current time based on the heat dissipation quantity per unit time qb and the elapsed time td. The memory information update device 32A calculates the heat dissipation quantity Qb from the previous calculation of the accumulated heat quantity to the current time (Qb = qb × td), and calculates the current mechanical brake accumulated heat quantity Q by subtracting the heat dissipation quantity Qb from the mechanical brake accumulated heat quantity Q.

[0143] When the current mechanical brake accumulated heat quantity Q is calculated in step S230, the process proceeds to step S235. In step S235, the stored information update device 32A updates the mechanical brake accumulated heat quantity Q included in the vehicle information of the k-th transport vehicle 20 in the nonvolatile memory 102 via the wireless communication device 35, and the process proceeds to step S240.

[0144] In step S240, the stored information updating device 32A adds 1 to the variable k, and the process proceeds to step S245.

[0145] In step S245, the stored information update device 32A determines whether the variable k is greater than the number of controlled transport vehicles 20. If it is determined in step S245 that the variable k is equal to or less than the number of transport vehicles 20, the process proceeds to step S215. If it is determined in step S245 that the variable k is greater than the number of transport vehicles 20, the process proceeds to step S250.

[0146] In step S250, the stored information update device 32A acquires the road resistance Fr for each node from the map information of all the transport vehicles 20, and transmits the latest value of the road resistance Fr of each node to all the transport vehicles 20. Each transport vehicle 20 replaces the road resistance Fr included in the map information stored in the map / vehicle information storage unit 157A with the received latest road resistance Fr. In other words, the transport vehicle 20 updates the map information based on the information from the control server 31A. When the update process of the road resistance Fr of the map information is completed in step S250, the process shown in the flowchart of FIG. 16 ends.

[0147] According to this embodiment, the vehicle control device 100A can obtain the latest road resistance Fr estimated from the driving records of not only the vehicle itself but also other vehicles. Furthermore, the vehicle control device 100A can obtain the mechanical brake accumulated heat quantity Q calculated based on the heat dissipation quantity qb that takes meteorological information into consideration. Therefore, the vehicle control device 100A can calculate the protective speed limit Vb with higher accuracy. As a result, the vehicle body 21 can be stopped normally with higher reliability.

[0148] The following modified examples are also within the scope of the present invention, and it is possible to combine the configuration shown in the modified example with the configuration described in the above embodiment, to combine the configurations described in the different embodiments above, or to combine the configurations described in the different modified examples below.

[0149] <Variation 1> In the first embodiment, an example has been described in which the transport vehicle 20 is provided with a load sensor 111, and the vehicle control device 100 calculates the protective speed limit Vb based on the load W and the traveling speed V. However, the present invention is not limited to this.

[0150] <Variation 1-1> The vehicle control device 100 may calculate the protective speed limit Vb without using the load weight W acquired by the load weight sensor 111. In this case, it is preferable that the vehicle weight M is the vehicle weight taking into account the maximum load weight, rather than the vehicle weight when unladen.

[0151] <Variation 1-2> The vehicle control device 100 may calculate the protective speed limit Vb without taking into account the road surface resistance Fr included in the map information.

[0152] <Variation 2> The method of calculating the mechanical brake accumulated heat quantity Q is not limited to the method described in the above embodiment.

[0153] <Variation 2-1> The amount of heat generated Qa of the mechanical brake device 127 and the amount of temperature change (temperature rise) of the mechanical brake device 127 due to heat generation are proportional to each other. Therefore, when the vehicle control device 100 detects the operation of the mechanical brake device 127, the vehicle control device 100 may calculate the amount of heat generated Qa based on the change in temperature of the mechanical brake device 127 acquired by the brake temperature sensor 116. The vehicle control device 100 calculates the amount of mechanical brake accumulated heat Q accumulated in the mechanical brake device 127 based on the calculated amount of heat generated Qa.

[0154] As described above, in this modification, the vehicle control device 100 calculates the mechanical brake accumulated heat quantity Q based on the temperature of the mechanical brake device 127, and calculates the protective speed limit Vb based on the mechanical brake accumulated heat quantity Q. According to this configuration, the mechanical brake accumulated heat quantity Q can be calculated with higher accuracy.

[0155] <Variation 2-2> The mechanical brake heat quantity calculation unit 153 may calculate the heat quantity Qa by the following formula (5) in consideration of the amount of change ΔN in potential energy from when the mechanical brake device 127 starts operating until the vehicle stops.

[0156]

number

[0157] The amount of change ΔN in potential energy is calculated based on the braking distance L from the start of operation of the mechanical brake device 127 to the vehicle stopping, the route gradient θ from the map information, the load W, and the vehicle weight M. In the above embodiment, the braking distance L is calculated using equation (3), but it may also be calculated as an integral value of the traveling speed V or as a fluctuation amount of the vehicle position.

[0158] In this way, when the vehicle control device 100 according to this modified example detects the operation of the mechanical brake device 127, it calculates the mechanical brake accumulated heat quantity Q based on the route gradient θ and the traveling speed V acquired by the speed sensor 114. Furthermore, the vehicle control device 100 calculates the protective speed limit Vb based on the calculated mechanical brake accumulated heat quantity Q. According to this configuration, when the transport vehicle 20 travels on a downhill slope, for example, it is possible to more accurately calculate the protective speed limit Vb.

[0159] <Variation 2-3> The heat generation amount Qa may be stored in advance as a fixed value in the map and vehicle information storage unit 157. In this case, the heat generation amount Qa is determined from the measurement results of the heat generation amount generated by one operation of the mechanical brake device 127 through an experiment or the like.

[0160] <Variation 2-4> Alternatively, the mechanical brake heat quantity calculation unit 153 may calculate the heat quantity Qa by the following formula (6) using the heat quantity qa per unit time determined in advance by an experiment or the like.

[0161]

number

[0162] qa is the amount of heat generated per unit time, and is stored in advance in the map and vehicle information storage unit 157. te is the elapsed time from when the mechanical brake device 127 starts to operate until the vehicle comes to a stop.

[0163] <Variation 3> In the first embodiment, an example has been described in which the cumulative mechanical brake accumulated heat quantity U of the mechanical brake device 127 is compared with the cumulative mechanical brake actuation limit heat quantity Umax in step S146 in Fig. 10, and whether or not the mechanical brake device 127 has reached its actuation limit (wear limit) is determined based on the comparison result. However, instead of the processing of step S146 in Fig. 10, the cumulative mechanical brake wear amount may be compared with the cumulative mechanical brake limit wear amount, and whether or not the mechanical brake device 127 has reached its actuation limit (wear limit) may be determined based on the comparison result.

[0164] There is a certain relationship between the cumulative mechanical brake wear amount and the cumulative mechanical brake accumulated heat amount. The speed limit calculation unit 154 converts the cumulative mechanical brake accumulated heat amount into the cumulative mechanical brake wear amount. Furthermore, the speed limit calculation unit 154 determines whether the cumulative mechanical brake wear amount is greater than the cumulative mechanical brake activation limit wear amount. The cumulative mechanical brake activation limit wear amount is a threshold value determined based on the limit value at which the mechanical brake device 127 is not damaged during operation, and is stored in advance in the map / vehicle information storage unit 157. If the speed limit calculation unit 154 determines in step S146 that the cumulative mechanical brake wear amount is equal to or less than the cumulative mechanical brake activation limit wear amount, the process proceeds to step S149. If the speed limit calculation unit 154 determines in step S146 that the cumulative mechanical brake wear amount is greater than the cumulative mechanical brake activation limit wear amount, the process proceeds to step S170.

[0165] According to such a modification, it is possible to achieve the same effects as those of the above embodiment.

[0166] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments. [Explanation of symbols]

[0167] 1, 1A...traffic control system, 10...transport route, 11...travel route, 12...node, 20...transport vehicle, 21...vehicle body, 22...wheel, 30...control station, 31, 31A...control server, 32, 32A...storage information update device, 34A...weather information acquisition device, 35...wireless communication device, 100, 100A...vehicle control device, 101...processing device, 102...non-volatile memory (storage device), volatile memory (storage device), 110...sensor device, 111...load sensor, 112...position sensor, 113...direction sensor, 114...speed sensor, 115...steering angle sensor, 116...brake temperature sensor, 120...travel drive device, 121...engine, 122...generator, 123...power control device, 124L, 124R...travel motor, 125...steering device, 126...electric brake device, 127...mechanical brake device, 130...alarm device, 131...wireless communication device, 151...mechanical brake operation detection unit, 152...speed limit generation unit, 153...mechanical brake heat amount calculation unit , 154...Speed ​​limit calculation unit, 155...Control target generation unit, 156...Autonomous driving control unit, 157, 157A...Map and vehicle information storage unit, Ea...Allowable kinetic energy, Fr...Road resistance, g...Gravitational acceleration, G...Thrust, h...Elevation difference, L...Braking distance, La...First distance, Lb...Second distance, M...Vehicle weight, Q...Mechanical brake accumulated heat, qa...Heat amount per unit time, Qa...Heat amount, qb...Heat dissipation amount per unit time, Qb...Heat dissipation amount, qb1...Heat dissipation amount on sunny days, qb2...Cloud Heat dissipation during daytime driving, Qmax...limit heat quantity for mechanical brake activation (predetermined value), R...deceleration force, t...road surface resistance update time, T...accumulated heat calculation time, tm...maintenance time, U...cumulative accumulated heat quantity for mechanical brake, Umax...cumulative limit heat quantity for mechanical brake activation (predetermined value), V...traveling speed (vehicle speed), Va...route speed limit, Vb...protective speed limit (speed at which the vehicle can stop), Vc...speed limit, Vt...target speed, W...load capacity, ΔN...change in potential energy, Δt...elapsed time width, θ...route gradient

Claims

1. The car body and a wheel provided on the vehicle body; a position sensor for acquiring the position of the vehicle body; a direction sensor for acquiring the direction of the vehicle body; a speed sensor for acquiring a traveling speed of the vehicle body; a travel drive device that drives the wheels and includes a mechanical brake device and an electric brake device that apply braking force to the wheels; a storage device for storing map information including a route shape, a route gradient, and a route speed limit of the travel route of the vehicle; a vehicle control device that generates a control target including a target speed based on a position of the vehicle body, an orientation of the vehicle body, a traveling speed of the vehicle body, and the map information, and controls the traveling drive device so that the traveling speed of the vehicle body becomes the target speed, The vehicle control device includes: calculates a protective speed limit for the mechanical brake device, which increases as time passes from when operation of the mechanical brake device is detected, including when the mechanical brake device is activated and then deactivated, based on the traveling speed acquired by the speed sensor and the route gradient included in the map information; calculates a first distance that can be traveled when the route speed limit is set as an upper limit value of the target speed after a predetermined maintenance time has elapsed, within a predetermined elapsed time period after detection of operation of the mechanical brake device, the predetermined elapsed time period including a state in which the mechanical brake device is activated and then deactivated; calculating a second distance that can be traveled when the protective speed limit is set as an upper limit value of the target speed during the predetermined elapsed time period after detecting the operation of the mechanical brake device; When the first distance is shorter than the second distance, the vehicle is caused to travel with the smaller of the protection speed limit and the route speed limit as an upper limit value of the target speed; If the first distance is greater than the second distance, a maintenance request instruction is output while the vehicle body is kept stopped. A transport vehicle characterized by:

2. The transport vehicle according to claim 1, a load sensor for acquiring a load of the transport vehicle; The vehicle control device calculates the protective speed limit taking into account the load amount acquired by the load amount sensor. A transport vehicle characterized by:

3. The transport vehicle according to claim 1, The map information further includes a road surface resistance of the travel route, The vehicle control device calculates the protective speed limit taking the road surface resistance into account. A transport vehicle characterized by:

4. The transport vehicle according to claim 1, The vehicle control device includes: When the operation of the mechanical brake device is detected, the accumulated heat amount of the mechanical brake device is calculated based on the route gradient and the traveling speed acquired by the speed sensor; The protective speed limit is calculated based on the accumulated heat amount. A transport vehicle characterized by:

5. The transport vehicle according to claim 1, a brake temperature sensor for acquiring a temperature of the mechanical brake device; The vehicle control device includes: When the operation of the mechanical brake device is detected, the amount of accumulated heat of the mechanical brake device is calculated based on the temperature of the mechanical brake device acquired by the brake temperature sensor; The protective speed limit is calculated based on the accumulated heat amount. A transport vehicle characterized by:

6. The transport vehicle according to claim 1, a notification device that notifies a maintenance request for the transport vehicle in response to the maintenance request instruction; The vehicle control device includes: When the operation of the mechanical brake device is detected, a cumulative value of the accumulated heat amount of the mechanical brake device is calculated; When the calculated cumulative value of the accumulated heat amount exceeds a predetermined value, the maintenance request instruction is output to the notification device. A transport vehicle characterized by:

7. The transport vehicle according to claim 1, The vehicle control device includes: calculating a deceleration rate when only the electric brake device is used based on the route gradient included in the map information and the traveling speed acquired by the speed sensor; The target speed is reduced at a position closer to the vehicle body than the position at which the route speed limit is reduced based on the calculated deceleration. A transport vehicle characterized by:

8. The transport vehicle according to claim 3, The vehicle control device includes: calculating the road surface resistance based on the traveling speed acquired by the speed sensor when operation of the mechanical brake device is detected, the position of the vehicle body acquired by the position sensor when operation of the mechanical brake device is detected, the position of the vehicle body acquired by the position sensor when the vehicle body is stopped by operation of the mechanical brake device, and the route gradient; The road surface resistance of the map information is updated based on the calculated road surface resistance. A transport vehicle characterized by:

9. A traffic control system including the transport vehicle according to claim 1 and a control server that performs traffic control of the transport vehicle, The vehicle control device includes: When the operation of the mechanical brake device is detected, the accumulated heat amount of the mechanical brake device is calculated based on the traveling speed acquired by the speed sensor; transmitting the calculated accumulated heat amount of the mechanical brake device and the time when the accumulated heat amount was calculated to the control server; The control server Get weather information, determining a heat dissipation amount per unit time based on the acquired weather information; calculating a corrected accumulated heat quantity by correcting the accumulated heat quantity based on the elapsed time from the time when the accumulated heat quantity was calculated and the heat radiation quantity per unit time; transmitting the corrected accumulated heat quantity to the vehicle control device of the transport vehicle; The vehicle control device calculates the protective speed limit based on the corrected accumulated heat amount. A traffic control system characterized by:

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