Control system for a transport vehicle

Abstract

The present application provides a control system for a transport vehicle that can suppress a reduction in the travel speed of the transport vehicle while suppressing skidding of the transport vehicle. One embodiment of the present application is a control system that causes a transport vehicle (100) to travel based on a control target that includes a target path. The control system generates the control target based on map information, a load amount, and a skid index, wherein the map information includes information on a travel road (WP) traveled by the transport vehicle (100) and information on a plurality of travel sections (TS) obtained by dividing the travel road (WP), the load amount is a load amount of the transport vehicle (100) in each travel section (TS), and the skid index indicates the degree of difficulty of skidding of the travel road (WP) in each travel section (TS). The control system expands the turning radius of a turning path included in the target path of the travel section (TS) when the skid index of at least one travel section (TS) is below a prescribed threshold.

Description

TECHNICAL FIELD

[0001] The present application relates to a control system for a carrying vehicle. BACKGROUND

[0002] An invention related to a system for managing operation of a mine machine has been known from the past (see Patent Literature 1 below). The operation management system for the mine machine generates speed limit information that changes a speed limit when the mine machine travels on a travel road corresponding to travel road information, based on the travel road information and position information (the document, paragraph 0007, claim 1, abstract, etc.). Further, the travel road information includes at least information related to a water amount of the travel road on which the mine machine operating in a mine travels. In addition, the position information is information about a position of the travel road corresponding to the travel road information.

[0003] According to the operation management system for the mine machine, it is possible to suppress the slip of the mine machine traveling on the travel road in the mine, to prevent the deterioration of the fuel consumption of the mine machine, and to suppress the wear of the wheel (the document, paragraph 0023, etc.).

[0004] PRIOR ART DOCUMENT

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2013-196051 SUMMARY

[0007] In the above-described conventional operation management system for the mine machine, the mine machine such as a dump truck successively calculates its own position by a vehicle-mounted position information detection device, and compares geographical information of the travel road included in the operation information and the self vehicle position information. Further, the mine machine travels at a travel speed (speed limit) set with respect to each travel road so as not to deviate from the travel road (the document, paragraph 0054, etc.). Therefore, when the water amount of the travel road increases to a state where the slip is easy, there is a concern that the travel speed of the mine machine will be unnecessarily reduced.

[0008] The present application provides a control system for a carrying vehicle that can suppress a reduction in travel speed of the carrying vehicle while suppressing the slip of the carrying vehicle.

[0009] One embodiment of the present application is a control system of a transport vehicle that causes the transport vehicle to travel based on a control target including a target path, which is generated based on map information, a load amount of the transport vehicle, and a slip index, wherein the map information includes information of a travel road on which the transport vehicle travels and information of a plurality of travel sections into which the travel road is divided, the load amount is a load amount of the transport vehicle in each of the travel sections, and the slip index indicates a slip easiness of the travel road in each of the travel sections, and the control system causes a turn radius of a turn path included in the target path of at least one of the travel sections to be larger than a turn radius of a turn path included in the target path of the travel section in a case where the slip index of the travel section is less than a predetermined threshold value.

[0010] Effects of Invention

[0011] According to the above one embodiment of the present application, it is possible to provide a control system of a transport vehicle that can suppress a reduction in travel speed of the transport vehicle while suppressing a slip of the transport vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0012] FIG. 1 is a schematic diagram illustrating an embodiment of the control system of the transport vehicle of the present application.

[0013] FIG. 2 is a functional block diagram of the transport vehicle illustrated in FIG. 1

[0014] FIG. 3 is a flowchart illustrating a flow of a control target generation process performed by the control system illustrated in FIG. 1

[0015] FIG. 4 is a plan view of a part of a travel road on which the transport vehicle illustrated in FIG. 1

[0016] FIG. 5 is a flowchart of a process of updating the subsequent travel section illustrated in FIG. 3

[0017] FIG. 6 is a diagram illustrating an example of a method of dividing a subsequent travel section into a plurality of sub-sections.

[0018] FIG. 7 is a block diagram illustrating a modified example of the control system illustrated in FIG. 1 DETAILED DESCRIPTION

[0019] Hereinafter, an embodiment of the control system of the transport vehicle of the present application will be described with reference to the accompanying drawings. FIG. 1 ​​​​​is a schematic diagram of the control system 1 of the present embodiment. FIG. 2 is FIG. 1 is a functional block diagram of the haulage vehicle 100.

[0020] The control system 1 of the present embodiment controls one or more haulage vehicles 100 traveling in unpaved travel roads WP in work sites such as mines and construction sites of open-pit mining, for example. The control system 1 controls an unmanned haulage vehicle 100 having no operator or driver, for example, to travel autonomously. The control system 1 is composed of the control device 110 and the communication device 120 mounted on the haulage vehicle 100, for example.

[0021] FIG. 1 In the example shown, the haulage vehicle 100 is a dump truck that hauls earth and sand, ore, and the like. In addition, the control object of the control system 1 is not limited to the dump truck or other haulage vehicles 100 such as wheel loaders and hydraulic excavators, and can be other work machines such as a motor grader, for example. As shown in FIG. 2 The haulage vehicle 100 has the control device 110, the communication device 120, the position sensor 130, the speed sensor 140, the acceleration sensor 150, the load amount sensor 160, the drive system 170, and the actuator 180, for example.

[0022] The control device 110 has a slip index estimation section 111, a storage section 112, a control target generation section 113, a control command generation section 114, and an input / output section 115, for example. Although not shown, the control device 110 can be composed of a microcontroller and firmware including one or more processing devices such as a CPU and one or more storage devices such as a ROM and a RAM, for example. FIG. 2 The sections of the control device 110 shown represent the functions of the control device 110 implemented by execution of a program stored in the storage device by the processing device, for example.

[0023] The communication device 120 is a wireless communicator that is connected to the control device 110 via the input / output section 115 and communicates with the outside via a wireless communication circuit RL, for example. More specifically, the communication device 120 communicates with the communication device 120 of another haulage vehicle 100 having the same configuration as the haulage vehicle 100 shown, for example. FIG. 2 The communication device 120 is a wireless communicator that is connected to the control device 110 via the input / output section 115 and communicates with the outside via a wireless communication circuit RL, for example. More specifically, the communication device 120 communicates with the communication device 120 of another haulage vehicle 100 having the same configuration as the haulage vehicle 100 shown, for example.

[0024] The position sensor 130 is connected to the control device 110 via the input / output section 115, for example, and acquires position information of the haulage vehicle 100 and outputs it to the control device 110. The position sensor 130 can be composed of a receiver of a Global Navigation Satellite System (GNSS) mounted on each haulage vehicle 100, for example.

[0025] The speed sensor 140 is connected to the control device 110 via the input-output section 115, for example, detects the speed of the carrying vehicle 100, and outputs to the control device 110. The speed sensor 140 can be constituted by a wheel speed sensor, for example. In addition, the speed sensor 140 can also calculate the speed of the carrying vehicle 100 based on the temporal change in the position information of the carrying vehicle 100 acquired by the position sensor 130.

[0026] The acceleration sensor 150 is connected to the control device 110 via the input-output section 115, for example, detects the acceleration of the carrying vehicle 100, and outputs to the control device 110. The acceleration sensor 150 can be constituted by an inertial measurement unit (IMU), for example. In addition, the acceleration sensor 150 can also calculate the acceleration of the carrying vehicle 100 based on the temporal change in the position information of the carrying vehicle 100 acquired by the position sensor 130.

[0027] The load amount sensor 160 is connected to the control device 110 via the input-output section 115, for example, detects the weight of the load, that is, the load amount, loaded in the carrying vehicle 100, and outputs to the control device 110. The load amount sensor 160 detects the load amount of the carrying vehicle 100 by measuring the load acting on the suspension device of the carrying vehicle 100 and the pressure of the working oil in the hydraulic cylinder, for example.

[0028] The drive system 170 is connected to the control device 110 via the input-output section 115, for example, generates a driving force for causing the carrying vehicle 100 to travel based on the control command input from the control device 110. The drive system 170 includes an engine, a generator, a travel motor or a hydraulic motor, a wheel or a track, and the like mounted on the carrying vehicle 100, for example.

[0029] The actuator 180 is connected to the control device 110 via the input-output section 115, for example, performs driving support of the carrying vehicle 100 or causes the carrying vehicle 100 to travel autonomously based on the control command input from the control device 110. The actuator 180 includes a brake operation actuator, an accelerator operation actuator, a steering actuator, and the like, for example.

[0030] The operation of the control system 1 of the present embodiment will be described below with reference to the flowchart of Fig. 1. FIG. 3 to FIG. 6

[0031] FIG. 3 is a flowchart showing the flow of control target generation processing performed by the control system 1 of the present embodiment. The control system 1 generates a control target including a target path in the control device 110 of each carrying vehicle 100 by executing each processing shown in FIG. 3 FIG. 2 ​​The control device 110 mounted on each of the transport vehicles 100 executes the following processing P1: the map information MI stored in the storage section 112 is acquired by the control target generation section 113.

[0032] FIG. 4 is a plan view showing a part of a travel road WP on which the transport vehicle 100 travels. The map information MI stored in the storage section 112 of the control device 110 includes, for example, information of the travel road WP on which the transport vehicle 100 travels, and information of a plurality of travel sections TS obtained by dividing the travel road WP. The travel road WP is, for example, an unpaved road for the transport vehicle 100 to travel in a work site such as an open-pit mine and an engineering site.

[0033] In the travel road WP, for example, a travel path TR of the transport vehicle 100 is defined. The travel path TR is, for example, an imaginary line that passes through the center or the vicinity thereof in the width direction of the travel road WP and extends along the travel road WP, and includes a curved turning path CR and a straight straight path SR. In addition, the travel path TR has a plurality of nodes ND. The nodes ND are, for example, imaginary points arranged at equal intervals on the travel path TR.

[0034] The turning path CR and the straight path SR included in the travel path TR can be classified, for example, on the basis of a threshold value of a curvature set in advance and a curvature of the travel path TR. In this case, in the travel path TR, a portion in which the curvature is equal to or greater than the threshold value is classified as the turning path CR, and a portion in which the curvature is less than the threshold value is classified as the straight path SR.

[0035] The turning path CR and the straight path SR included in the travel path TR can be classified, for example, on the basis of a threshold value of a lateral acceleration set in advance and a lateral acceleration acting on the transport vehicle 100 traveling along the travel path TR. In this case, in the travel path TR, a portion in which the lateral acceleration acting on the transport vehicle 100 is equal to or greater than the threshold value is classified as the turning path CR, and a portion in which the lateral acceleration is less than the threshold value is classified as the straight path SR.

[0036] The travel road WP is divided, for example, into a plurality of travel sections TS. The travel road WP is divided, for example, in such a manner that each of the travel sections TS includes a plurality of nodes ND. In this case, each of the travel sections TS includes at least one of the turning path CR and the straight path SR. In addition, the travel road WP can also be divided into a travel section TS including only the turning path CR and a travel section TS including only the straight path SR. Table 1 below shows an example of the map information MI stored in the storage section 112 of the control device 110 mounted on each of the transport vehicles 100.

[0037]

Table 1

[0038] Node ID Travel section ID Node information Limit speed Turn identification 1 1 (X1, Y1, D1) V1 0 2 1 (X2, Y2, D2) V2 1 3 2 (X3, Y3, D3) V3 1 … … … … … n m (Xn, Yn, Dn) Vn 0 or 1 … … … … …

[0039] As shown in Table 1, the map information MI includes, for example, a travel section ID, node information, a limit speed, and a turn identification for each node ID. The node ID is an identification number given to each node ND. The travel section ID is, for example, an identification number given to each travel section TS. Further, N and m of Table 1 each represent an arbitrary natural number. The node information is, for example, a position coordinate of each node ND. The limit speed is, for example, determined based on a curvature of a travel path TR within each travel section TS. The turn identification is "0" in a case where the node ND is located on a straight path SR and is "1" in a case where the node ND is located on a curved path CR.

[0040] The control system 1 executes, in the processing P1 shown in Fig. 1, the processing P2 of acquiring the position information of each of the conveyance vehicles 100 and the processing P3 of acquiring the speed of each of the conveyance vehicles 100. FIG. 3 The control system 1 acquires, in the processing P1 shown in Fig. 1, the map information MI shown in Table 1 from the storage section 112 of the control device 110 mounted on each of the conveyance vehicles 100. Then, the control system 1 executes the processing P2 of acquiring the position information of each of the conveyance vehicles 100 and the processing P3 of acquiring the speed of each of the conveyance vehicles 100. FIG. 2 The control system 1 acquires, in the processing P1 shown in Fig. 1, the map information MI shown in Table 1 from the storage section 112 of the control device 110 mounted on each of the conveyance vehicles 100. Then, the control system 1 executes the processing P2 of acquiring the position information of each of the conveyance vehicles 100 and the processing P3 of acquiring the speed of each of the conveyance vehicles 100.

[0041] Specifically, in the processing P2, the control device 110 of each of the conveyance vehicles 100 acquires the position information of the conveyance vehicle 100 from the position sensor 130 mounted on the conveyance vehicle 100. Further, in the processing P3, the control device 110 of each of the conveyance vehicles 100 acquires the speed of the conveyance vehicle 100 from the speed sensor 140 mounted on the conveyance vehicle 100.

[0042] Then, the control system 1 executes the processing P4 of determining the travel section TS in which each of the conveyance vehicles 100 is currently traveling. Specifically, in the processing P4, the control target generation section 113 of each of the conveyance vehicles 100 determines the travel section ID based on the map information MI and the position information of the conveyance vehicle 100 acquired in the previous processing P1 and P2, thereby determining the travel section TS in which the conveyance vehicle 100 is currently traveling.

[0043] Then, the control system 1 executes the processing P5 of determining the subsequent travel section of each of the conveyance vehicles 100. Specifically, in the processing P5, the control target generation section 113 of each of the conveyance vehicles 100 determines the travel section ID of the travel section TS in which the conveyance vehicle 100 will travel next based on the map information MI, the speed, and the travel section TS in which the conveyance vehicle 100 is currently traveling, which are acquired in the previous processing P1, P3, and P4.

[0044] Thus, the control target generating section 113 can determine the travel section TS, i.e., the subsequent travel section, in which the truck 100 will travel subsequently. The subsequent travel section becomes the object for which the control target generating section 113 generates the control target. In the process P5, the control target generating section 113 of each truck 100 determines, for example, an area composed of one or more subsequent travel sections in which the truck 100 will enter within a prescribed time.

[0045] Then, the control system 1 executes the process P6 of judging whether the subsequent travel section includes the turning path CR. Specifically, in the process P6, the control system 1 acquires the map information MI of the subsequent travel section from the storage section 112, for example, by the control target generating section 113 of each truck 100, and judges whether the turning path CR is contained in the travel section TS in which each truck 100 will travel subsequently.

[0046] More specifically, in the process P6, the control target generating section 113 judges whether the subsequent travel section, i.e., the travel section TS, includes the node ND whose turning identification is "1", for example, based on the acquired map information MI.

[0047] In the process P6, the control target generating section 113 judges that the subsequent travel section does not include the turning path CR (NO) in the case where the subsequent travel section, i.e., the travel section TS, does not contain the node ND whose turning identification is "1", that is, judges that the subsequent travel section is the straight path SR. In this case, the control target generating section 113 does not execute the process P7 of updating the subsequent travel section, and executes the process P8 of generating the control target based on the map information MI of the subsequent travel section. The process P8 will be described later.

[0048] On the other hand, in the process P6, the control target generating section 113 judges that the subsequent travel section includes the turning path CR (YES) in the case where the subsequent travel section, i.e., the travel section TS, contains the node ND whose turning identification is "1", and executes the process P7 of updating the subsequent travel section.

[0049] FIG. 5 is FIG. 3 The flowchart of the process P7 of updating the subsequent travel section is shown in FIG. 9. If the process P7 is started, the control target generating section 113 first executes the process P701 of calculating an initial value of the target speed of the subsequent travel section. In the process P701, the control target generating section 113 calculates the average value of the limit speeds of the plurality of nodes ND contained in the subsequent travel section, i.e., the travel section TS in which the truck 100 will travel subsequently, based on the map information MI, and sets the average value as the initial value of the target speed.

[0050] Then, the control target generation unit 113 performs the following process P702: for example, it obtains the load of the transport vehicle 100 from the load sensor 160 via the input / output unit 115, that is, the weight of the load loaded in the transport vehicle 100.

[0051] Then, the control device 110 of each transport vehicle 100 executes a process P703, for example, to obtain the state of the travel path WP. In this process P703, the slippage index estimation unit 111 of the control device 110 estimates, for example, the coefficient of friction between the contact part of the transport vehicle 100's wheels or tracks and the travel path WP, and the moisture content of the travel path WP, based on the state of the travel path WP. Here, the slippage index estimation unit 111 estimates at least one of the coefficient of friction and the moisture content by, for example, any of the following methods.

[0052] The coefficient of friction between the ground contact point of the transport vehicle 100 and the travel path WP affects the magnitude of the force exerted on the ground contact point of the transport vehicle 100 by the travel path WP, thereby altering the motion of the transport vehicle 100. Therefore, this coefficient of friction can be obtained, for example, from the speed sensor 140, acceleration sensor 150, and load sensor 160, respectively, and estimated based on the equation of motion using the weight, speed, and acceleration of the transport vehicle 100, including its load.

[0053] Furthermore, the moisture content of the travel path WP affects the coefficient of friction between the ground contact area of ​​the transport vehicle 100 and the travel path WP. That is, when the moisture content of the travel path WP increases, the travel path WP becomes muddy, and the coefficient of friction between the ground contact area of ​​the transport vehicle 100 and the travel path WP decreases. Therefore, the moisture content of the travel path WP, like the coefficient of friction, can be estimated based on the equation of motion using the weight, speed, and acceleration of the transport vehicle 100, including its load capacity.

[0054] Furthermore, the moisture content of the driving road WP can be estimated, for example, by obtaining meteorological information via the communication device 120, and estimating it based on the precipitation and humidity contained in that meteorological information. Additionally, the moisture content of the driving road WP can also be estimated, for example, by obtaining the amount of water sprayed onto the driving road WP via the communication device 120, and estimating it based on that amount of water sprayed. According to these methods, even if the transport vehicle 100 does not have sensors such as the speed sensor 140, acceleration sensor 150, and load sensor 160, the moisture content of the driving road WP can still be estimated.

[0055] Then, the control device 110 of each of the transport vehicles 100, for example, executes the process P704 of estimating the slip index SI. The slip index SI is an index indicating the degree of slip of the transport vehicle 100 running on the travel road WP. The smaller the slip index SI, the more likely the transport vehicle 100 running on the travel road WP slips, and the larger the slip index SI, the less likely the slip. In this process P704, the control device 110, for example, estimates the slip index SI of the plurality of nodes ND based on the state of the travel road WP acquired by the previous process P703 by the slip index estimation section 111.

[0056] More specifically, the slip index estimation section 111, in the process P704, for example, sets the coefficient of friction μ between the ground-contact portion of the transport vehicle 100 and the travel road WP acquired by the previous process P703 as the slip index SI. In this case, the slip index SI has a positive correlation with the coefficient of friction μ of the travel road WP. In addition, the slip index estimation section 111, in the process P704, for example, calculates the reciprocal of the water amount of the travel road WP acquired by the previous process P703 as the slip index SI. In this case, the slip index SI has a negative correlation with the water amount of the travel road WP.

[0057] As shown in Table 2 below, the slip index estimation section 111, for example, stores the slip index SI set or calculated by the process P704 together with the time of the setting or calculation in the storage section 112 for each node ID corresponding to the plurality of nodes ND.

[0058]

Table 2

[0059] Node ID Slip index Time 1 μ1 T1 2 μ2 T2 3 μ3 T3 … … … n μn Tn … … …

[0060] In addition, the plurality of transport vehicles 100 share the latest slip index SI stored in the storage section 112 of each of the control devices 110. The slip index estimation section 111, for example, acquires the slip index SI of the latest time for each node ID from the control device 110 of the other transport vehicle 100 via the input and output section 115 and the communication device 120. The slip index estimation section 111 stores the slip index SI of the latest time acquired from the other transport vehicle 100 in the storage section 112 together with the time.

[0061] Then, the control device 110 of each of the transport vehicles 100, for example, executes the process P705 of dividing the travel section to be run. In this process P705, the control device 110, for example, acquires the slip index SI corresponding to each node ID of the plurality of nodes ND included in the travel section TS to be run from the storage section 112 by the control target generation section 113. Further, the control target generation section 113 divides the travel section TS to be run into a plurality of sub-sections based on the slip index SI of each node ID acquired.

[0062] FIG. 6 This is a diagram illustrating an example of a method that divides a subsequent driving interval into multiple sub-intervals based on the slip index SI for each node ID. FIG. 6 In the diagram shown, the horizontal axis represents the node IDs of multiple nodes ND, and the vertical axis represents the slippage index SI. Furthermore, the continuous intervals of nodes ND with slippage index SI less than the threshold μt are designated as "easy slippage sub-intervals TSs", and the continuous intervals of nodes ND with slippage index SI greater than the threshold μt are designated as "difficult slippage sub-intervals TSg", thereby dividing the subsequent driving interval, i.e., the driving interval TS, into multiple sub-intervals.

[0063] The threshold μt of the slippage index SI can, for example, use a preset value. Alternatively, the threshold μt of the slippage index SI can be determined, for example, to simultaneously satisfy the following first and second conditions: The first condition is, for example, to minimize the sum of the deviation or standard deviation of the slippage index SI in the easy-slipping sub-interval TSs and the deviation or standard deviation of the slippage index SI in the difficult-slipping sub-interval TSg. The second condition is to maximize the difference between the average value of the slippage index SI of the entire easy-slipping sub-interval TSs and the average value of the slippage index SI of the entire difficult-slipping sub-interval TSg.

[0064] Then, the control device 110 of each transport vehicle 100 executes, for example, process P706: calculating the entry position and entry orientation of the transport vehicle 100 into the first sub-section TSg it enters within the subsequent travel interval. Here, as FIG. 4 As shown, the control target generation unit 113 of the control device 110 obtains, for example, the coordinates of the first node ND of the travel interval TS in which the transport vehicle 100 subsequently travels, as the entry position AP for entering the first sub-interval TSg. Furthermore, the control target generation unit 113 calculates, for example, the entry direction AD from the last node ND of the travel interval TS in which the transport vehicle 100 is currently traveling, to the entry position AP of the subsequent travel interval, i.e., node ND, as the entry direction for entering the first sub-interval TSg.

[0065] Then, in each transport vehicle 100, the control target generation unit 113 of the control device 110 performs, for example, the process P707 of setting the index, i.e., variable k, of multiple sub-intervals TSg to 1 (k=1). Then, the control target generation unit 113 performs the process P708: calculating the radius of curvature of the travel path TR that the transport vehicle 100 can follow in the first (kth) sub-interval TSg, that is, the following turning radius Ra.

[0066] In this process P708, the target generation unit 113 calculates the followable turning radius Ra of the k-th sub-intervals TSg and TSs of the subsequent travel interval based on the target speed, load, and slippage index SI calculated by the previous processes P701, P702, and P704. More specifically, for example, the maximum lateral acceleration a of the transport vehicle 100 during travel is calculated based on the average of the slippage index SI of the multiple nodes ND contained in the first sub-interval TSg of the subsequent travel interval and the weight of the transport vehicle 100 including the load. Then, the followable turning radius Ra is calculated using the maximum lateral acceleration a and the target speed V based on the following equation (1).

[0067] Ra = V 2 / a···(1)

[0068] Then, the control target generation unit 113 performs the following process P709: calculating the maximum value of the radius of curvature of the travel path TR in which the transport vehicle 100 can travel within the travel road WP in the first (kth) sub-interval TSg, that is, the maximum permissible turning radius Rmax. The control target generation unit 113 calculates the maximum permissible turning radius Rmax, for example, in the following order.

[0069] First, such as FIG. 4 As shown, the line L1, which passes through the entry position (node ​​ND) and is perpendicular to the entry orientation AD, is calculated from the first sub-section TSg of the subsequent travel interval. The radius Cmax of the arc is calculated such that the arc centered on this line L1 and on the inside of the turn of the transport vehicle 100 is tangent to the outer boundary of the curve of the travel road WP. The radius of this arc Cmax is calculated and used as the maximum permissible turning radius Rmax of the first sub-section TSg.

[0070] Then, the control target generation unit 113 performs the following process P710: determining whether the followable turning radius Ra in the first (kth) sub-interval TSg is below the maximum permissible turning radius Rmax. In this process P710, for example, when the control target generation unit 113 determines that the followable turning radius Ra is below the maximum permissible turning radius Rmax, it performs the process P711: determining whether the variable k is equal to the total number N of the sub-intervals TSs and TSg in the subsequent driving interval.

[0071] In process P711, if the control target generation unit 113 determines that variable k is not equal to the total number N of sub-intervals TSs and TSg of the subsequent travel interval (no), it executes the next process P712. In process P712, the control target generation unit 113 calculates the entry position AP and entry orientation AD of the transport vehicle 100 entering the subsequent sub-interval, that is, entering the second (k+1)th sub-interval TSs after the transport vehicle 100 travels.

[0072] In this process, as shown on page 712... FIG. 4 As shown, the control target generation unit 113, for example, obtains a straight line L1 that passes through node ND of the entry position AP of the first (k) sub-interval TSg and is perpendicular to the entry orientation AD of the sub-interval TSg. Furthermore, the control target generation unit 113 obtains an arc Ca with node ND of the entry position AP of the first (k) sub-interval TSg as its endpoint, having a center on the straight line L1, and having a radius equal to the followable turning radius Ra of the first (k) sub-interval TSg.

[0073] Furthermore, the control target generation unit 113 obtains a straight line L2 that has a central angle θ between itself and the straight line L1, and passes through the center of the arc Ca and the first node ND of the second (k+1)th sub-interval TSs. The control target generation unit 113 then calculates the intersection point between the straight line L2 and the arc Ca as the entry position AP of the second (k+1)th sub-interval TSs, and calculates the tangent direction of the arc Ca in the entry position AP as the entry orientation AD of the second (k+1)th sub-interval TSs.

[0074] Then, the target generation unit 113 executes the process P713 of setting the variable k to k = k + 1 and accumulating, and similarly executes the processes P708 to P710 for the subsequent sub-intervals, namely the second (k+1) sub-interval TSs and the first (k) sub-interval TSg.

[0075] Furthermore, in process P710, if the target generation unit 113 determines that the followable turning radius Ra is greater than the maximum permissible turning radius Rmax, or if the followable turning radius Ra is not less than the maximum permissible turning radius Rmax (no), it executes process P714 to reduce the target speed. In this process P714, the target generation unit 113 reduces the target speed, for example, according to a preset ratio.

[0076] In addition, in processing P714, the target generation unit 113 may, for example, use the maximum permissible turning radius Rmax and the maximum lateral acceleration a to calculate the reduced target speed V based on the following equation (2).

[0077] V = (a·Rmax) 1 / 2 ···(2)

[0078] The process P714 of reducing the target speed V is executed on the basis of the result of the process P710 in a case where it is judged that the followable turning radius Ra is not below the maximum allowable turning radius Rmax (NO). Therefore, the target speed V calculated by the process P714 is smaller than the target speed V at the time when the followable turning radius Ra is calculated by the process P708. The control target generating portion 113 returns to the process P707 after the end of the process P714. Thus, the control target generating portion 113 uses the new target speed V to execute the processes after the process P708 again with respect to the first to Nth subintervals TSg, TSs of the subsequent travel interval.

[0079] The control target generating portion 113 judges that the variable k is equal to N (YES) in the process P711 if the processes after the process P708 are completed with respect to all of the N subintervals TSg, TSs of the subsequent travel interval, and executes a process P715 of generating the path information of the subsequent travel interval. In the process P715, the control target generating portion 113 generates the path information of the subsequent travel interval including the followable turning radius Ra and the target speed V with respect to all of the first to Nth subintervals TSg, TSs of the subsequent travel interval.

[0080] The followable turning radius Ra and the target speed V with respect to all of the subintervals TSg, TSs included in the path information of the subsequent travel interval are calculated on the basis of the slip index SI of each subinterval TSg, TSs as described above. Therefore, the control target generating portion 113 makes the turning radius of the turning path CR included in the target path larger in the easy-to-slip subinterval TSs in which the slip index SI is less than the prescribed threshold value μt than in the difficult-to-slip subinterval TSg in which the slip index SI is equal to or more than the prescribed threshold value μt within the travel interval TS. Therefore, the transfer vehicle 100 traveling on the basis of the path information of the subsequent travel interval is able to pass through the subsequent travel interval at the maximum speed at which slipping is prevented.

[0081] If the maximum target speed at which the transfer vehicle 100 prevents slipping is set as the maximum target speed, the followable turning radius Ra of each subinterval TSg, TSs at a target speed smaller than the maximum target speed can be calculated as shown below. The target speed smaller than the maximum target speed can be calculated on the basis of the maximum lateral acceleration a at which the transfer vehicle 100 traveling within each subinterval TSg, TSs does not slip. Further, the maximum lateral acceleration a in each subinterval TSg, TSs is determined, for example, on the basis of the weight of the transfer vehicle 100 including the load amount and the average value of the slip index SI in each subinterval TSg, TSs.

[0082] The smaller the target speed is, the smaller the followable turn radius Ra can be. Therefore, the minimum target speed can be set so that the transfer vehicle 100 traveling along the followable turn radius Ra touches the boundary of the inner side of the curve of the travel road WP and does not exceed the boundary of the inner side of the curve of the travel road WP. The control target generation section 113, for example, calculates the path information including the combination of the target speed and the followable turn radius Ra in the range from the minimum target speed to the maximum target speed.

[0083] The control target generation section 113, for example, calculates the length of the travel path TR of each of the sub-sections TSg, TSs of the subsequent travel section based on the calculated path information of the subsequent travel section and the map information MI acquired from the storage section 112 and sets it as the length of the circular arc. Also, the control target generation section 113, for example, calculates the passing time of each of the sub-sections TSg, TSs based on the calculated length of the travel path TR of each of the sub-sections TSg, TSs and the target speed and totals it, thereby calculating the passing time of the subsequent travel section.

[0084] As described above, the path information of the subsequent travel section calculated by the control target generation section 113 in the process P715 can be the path information through which the transfer vehicle 100 passes in the shortest time from the subsequent travel section, or the path information through which the transfer vehicle 100 passes in the set passing time longer than the shortest time. That is, the control target generation section 113 can generate a control target that causes the transfer vehicle 100 to pass through the travel section TS in the shortest time corresponding to the slip index SI. In addition, the control target generation section 113 can also generate a control target that causes the transfer vehicle 100 to pass through the travel section TS in the set time.

[0085] Then, the control target generation section 113 performs a process P716 of updating the map information MI of the subsequent travel section based on the map information MI and the path information of the subsequent travel section. The control target generation section 113, for example, calculates circular arcs with respect to each of the sub-sections TSg, TSs of the subsequent travel section and updates the travel path TR with a path in which these circular arcs are connected. The control target generation section 113 updates the position information of the node ND based on the updated travel path and updates the map information MI of the subsequent travel section based on the updated position information of the node ND.

[0086] The arcs used in updating the driving path TR for each sub-section TSg and TSs can be calculated, for example, as described below. The arc is calculated as follows: taking the entry position AP leading to each sub-section TSg and TSs as its endpoint, lying on a straight line perpendicular to the entry orientation AD leading to each sub-section TSg and TSs, having a center on the inside of the curve of the driving road WP, ​​and having a radius equal to the followable turning radius Ra of each sub-section TSg and TSs. Each arc of each sub-section TSg and TSs has a central angle θ between the first node ND of that sub-section TSg and TSs and the first node ND of the subsequent sub-section TSg and TSs.

[0087] That concludes the above. FIG. 5 The update shown is followed by processing of the driving section P7. Then, the control target generation unit 113 executes... FIG. 3 The process of generating control targets is shown on page P8.

[0088] In processing P8, the control target generation unit 113 generates, for example, a control target that uses the average of the restricted speeds of the nodes ND contained in the subsequent travel interval as the target speed, and includes the travel path TR or the position information of the nodes ND as the target path.

[0089] Furthermore, if the subsequent travel section includes a node ND marked with a turn symbol "1", that is, if the subsequent travel section includes a turning path CR, the control target generation unit 113 can generate a control target in process P8, for example, as described below. The control target generation unit 113 generates a control target including a target speed that has a speed distribution that decelerates the transport vehicle 100 before it enters the turning path CR and accelerates it after it exits the turning path CR. This allows for stable speed of the transport vehicle 100 traveling on the turning path CR, suppresses acceleration in the forward and backward directions of the transport vehicle 100 during the turn, and makes it easier to control the transport vehicle 100.

[0090] That concludes the above. FIG. 3 The control target generation process is shown. Then, FIG. 2 The control command generation unit 114 shown generates control commands for enabling the transport vehicle 100 to drive autonomously or for providing driving support to the transport vehicle 100 based on the control targets generated by the control target generation unit 113, through the control target generation process described above. The control commands may include, for example, at least one of the following: brake pedal operation amount, accelerator pedal operation amount, and steering angle operation amount of the actuator 180.

[0091] The function of the control system 1 of the transport vehicle in this embodiment will be explained below.

[0092] The carrying vehicle 100, for example, does not carry an operator and a driver, travels in accordance with a target path such as a travel path TR imparted, or stops when a travel trajectory in which the carrying vehicle 100 actually travels deviates from the target path by a fixed distance or more, judging as a path departure. The stop of the carrying vehicle 100 results in reduction of operating time, becoming a factor of reduction of productivity. In an off-road such as a travel road WP of a mine, state deterioration is easily caused by mud and the like, and the followability of the travel trajectory in which the carrying vehicle 100 actually travels with respect to the target path is reduced according to the deterioration of the state of the travel road WP. Therefore, in a case where the state of the travel road WP is deteriorated by watering and the like, there is a concern that the number of times of departure of the carrying vehicle 100 from the target path increases.

[0093] In contrast, the control system 1 of the carrying vehicle of the present embodiment causes the carrying vehicle 100 to travel based on a control target including a target path as described above. The control system 1 generates the control target based on map information MI including information of a travel road WP in which the carrying vehicle 100 travels and information of a plurality of travel sections TS obtained by dividing the travel road WP, a load amount of the carrying vehicle 100 in each travel section TS, and a slip index SI indicating a slip easiness of the travel road WP in each travel section TS. Further, the control system 1 expands a turning radius of a turning path CR included in the target path of at least one travel section TS in which the slip index SI is less than a prescribed threshold value μt, compared to a case where the slip index SI is the prescribed threshold value μt or more.

[0094] According to such a configuration, the control system 1 of the carrying vehicle according to the present embodiment can suppress reduction of a travel speed of the carrying vehicle 100 while suppressing slip of the carrying vehicle 100. In more detail, the control system 1 can determine a travel section TS in which slip is easy based on the slip index SI when generating the control target of the carrying vehicle 100 based on the map information MI, the load amount of the carrying vehicle 100, and the slip index SI. Further, the control system 1 expands the turning radius of the turning path CR included in the target path of the travel section TS in which slip is easy, thereby being able to reduce lateral acceleration acting on the carrying vehicle 100, and being able to suppress reduction of the travel speed of the carrying vehicle 100 while suppressing slip. Therefore, the carrying vehicle 100 is prevented from departing from the travel path TR, and it is possible to improve work efficiency of the carrying vehicle 100.

[0095] Further, in the control system 1 of the carrying vehicle of the present embodiment, the slip index SI has a positive correlation with a friction coefficient μ of the travel road WP. According to this configuration, in a case where the slip index SI is less than the threshold value μt, it is possible to judge that the travel road WP is in a state in which slip is easy.

[0096] In addition, in the control system 1 of the transport vehicle according to the present embodiment, the slip index SI has a negative correlation with the water amount of the travel road WP. According to this configuration, the slip easiness of the travel road WP can be determined based on the water amount of the travel road WP, and the control system 1 can be simplified without using a special sensor.

[0097] In addition, in the control system 1 of the transport vehicle according to the present embodiment, the control target further includes a target speed corresponding to the target path. In addition, the control system 1 can generate a control target that causes the transport vehicle 100 to pass through the travel section in the shortest time corresponding to the slip index SI. According to this configuration, the speed reduction of the transport vehicle 100 can be effectively suppressed.

[0098] In addition, in the control system 1 of the transport vehicle according to the present embodiment, the control target is generated so that the transport vehicle 100 passes through the travel section TS within a set time. According to this configuration, the speed of the transport vehicle 100 can be prevented from unnecessarily increasing, and the transport vehicle 100 can be more safely traveled.

[0099] In addition, in the control system 1 according to the present embodiment, the control target can include a speed target that causes the transport vehicle 100 to decelerate before the transport vehicle 100 enters the turning path CR and to accelerate after the transport vehicle 100 exits the turning path CR. According to this configuration, the transport vehicle 100 can be more stably traveled.

[0100] In addition, in the control system 1 of the transport vehicle according to the present embodiment, the control system 1 further includes a position sensor 130 that acquires position information of the transport vehicle 100, a load amount sensor 160 that acquires a load amount of the transport vehicle 100, a speed sensor 140 that acquires a speed of the transport vehicle 100, and an acceleration sensor 150 that acquires an acceleration of the transport vehicle 100. In addition, the control system 1 estimates the slip index SI corresponding to the position information based on the load amount, the speed, and the acceleration corresponding to the position information of the transport vehicle 100. According to this configuration, the estimation accuracy of the slip index SI corresponding to the position information of the travel road WP can be improved, and the slip of the transport vehicle 100 can be more reliably suppressed.

[0101] In addition, in the control system 1 of the transport vehicle according to the present embodiment, the slip index SI estimated based on the position information, the load amount, the speed, and the acceleration is shared among the plurality of transport vehicles 100. According to this configuration, the plurality of transport vehicles 100 can generate a control target using the latest slip index of the travel road WP, and the speed reduction of the transport vehicle 100 can be more reliably prevented, and the slip of the transport vehicle 100 can be more reliably prevented.

[0102] FIG. 7is a block diagram showing a modification of the control system 1 of the truck shown in the above-described embodiment. In this modification, the control system 1 further has a control tower 200 that receives the slip index SI from each truck 100 and sends a control target to the plurality of trucks 100, on the basis of the above-described configuration. In this modification, the control tower 200 has a communication device 210 and a control target generation section 220. The control target generation section 220 can be configured by a computer such as a microcontroller, for example, similarly to the control device 110 of the truck 100.

[0103] The control tower 200 performs a control control that exclusively allocates one truck 100 to each travel section TS, for example, in order to avoid interference among a plurality of unmanned trucks 100 without a riding operator and a driver. The control control sets the travel path TR in which the truck 100 exists to a closed state, for example, as disclosed in Japanese Patent No. 6368259, thereby prohibiting entry of other trucks 100, and can avoid interference of the trucks 100.

[0104] The control tower 200 receives the slip index SI from each truck 100 via the wireless communication circuit RL through the communication device 210. The control tower 200 generates a control target based on the slip index SI through the control target generation section 220 and sends the generated control target to the control device 110 of each truck 100. In addition, in this modification, the control target generation section 113 can be omitted from the control device 110 of the truck 100.

[0105] The control target generation section 220 of the control tower 200 can use a computer that can perform a high-load calculation, which is higher than the control device 110 whose power and space are limited for mounting on the truck 100. Therefore, it is possible to generate a control target that can travel in the shortest time based on the state of the travel road WP, with the plurality of trucks 100 as the target, using all the travel paths TR that can be obtained based on the loading place and the unloading place of the truck 100. Thus, it is possible to generate a control target from the start to the stop of the plurality of trucks 100, thereby predicting the position of each truck 100 with respect to time and performing a control control that avoids interference of the predicted trucks 100.

[0106] According to this modification, the control target generation section 220 of the control tower 200 generates a control target of the plurality of trucks 100 based on the loading place and the unloading place of the truck 100. Also, it is possible to make the plurality of trucks 100 travel safely in the shortest time based on the state of the travel road WP, that is, the slip index SI.

[0107] The above describes in detail the embodiment of the control system of the transport vehicle of the present application using the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like made within the scope of the gist of the present application are also included in the present application.

[0108] Explanation of Reference Signs

[0109] 1 Control system

[0110] 100 Transport vehicle

[0111] 130 Position sensor

[0112] 140 Speed sensor

[0113] 150 Acceleration sensor

[0114] 160 Load amount sensor

[0115] 200 Control tower

[0116] CR Turning path

[0117] MI Map information

[0118] SI Slip index

[0119] TS Travel section

[0120] WP Travel road

[0121] μ Friction coefficient

[0122] μt Threshold value

Claims

1. A control system for a transport vehicle, which enables the transport vehicle to travel based on a control objective including a target path and a target speed corresponding to the target path, characterized in that, The system acquires map information, including information about the road the transport vehicle is traveling on and information about multiple travel sections obtained by dividing the road, as well as the location information and speed of the transport vehicle. It then determines the travel section the transport vehicle is currently traveling in and the subsequent travel section the transport vehicle will subsequently travel in. If, based on the map information, it is determined that the subsequent driving section includes a turning path, the average of the speed limits of multiple nodes within the subsequent driving section is calculated based on the map information and used as the initial value of the target speed. Obtain the loading capacity of the transport vehicle and the slippage index, which represents the slippage difficulty of each of the multiple nodes. The subsequent driving section is divided into multiple sub-sections based on the slippage index of each node. Calculate the entry position and entry direction of the transport vehicle as it first enters the sub-region within the multiple sub-regions. The following turning radius of the transport vehicle within each of the sub-sections is calculated based on the target speed, the load capacity, and the slippage index. The maximum permissible turning radius within each sub-section is calculated based on the entry position and the entry orientation. If the followable turning radius is greater than the maximum permissible turning radius in any of the sub-intervals, the target speed is reduced and the followable turning radius is recalculated. A control target, including the followable turning radius and the target speed, is then generated for all sub-intervals in the subsequent driving interval. Therefore, if the slippage index of at least one sub-section of at least one of the driving sections is less than a predetermined threshold, the turning radius of the turning path contained in the target path of that driving section is increased compared to the case where the slippage index is above the predetermined threshold.

2. The control system for the transport vehicle according to claim 1, characterized in that, The slippage index is positively correlated with the friction coefficient of the road surface.

3. The control system for the transport vehicle according to claim 1, characterized in that, The slippage index is negatively correlated with the moisture content of the road surface.

4. The control system for the transport vehicle according to claim 1, characterized in that, The control system generates the control objective that enables the transport vehicle to pass through the travel zone in the shortest time corresponding to the slippage index.

5. The control system for the transport vehicle according to claim 4, characterized in that, Generate the control target that causes the transport vehicle to pass through the travel zone within a set time.

6. The control system for the transport vehicle according to claim 1, characterized in that, The control objectives include a speed objective of slowing down the transport vehicle before it enters the turning path and accelerating it after it exits the turning path.

7. The control system for the transport vehicle according to claim 1, characterized in that, It also includes: a position sensor for acquiring the position information of the transport vehicle; a load sensor for acquiring the load amount of the transport vehicle; a speed sensor for acquiring the speed of the transport vehicle; and an acceleration sensor for acquiring the acceleration of the transport vehicle. The slippage index corresponding to the location information is estimated based on the load, speed, and acceleration corresponding to the location information.

8. The control system for the transport vehicle according to claim 7, characterized in that, The multiple transport vehicles share the slippage index estimated based on the location information, the load, the speed, and the acceleration.

9. The control system for the transport vehicle according to claim 8, characterized in that, It also has a control console that receives the slippage index from each of the transport vehicles and sends the control target to the multiple transport vehicles.

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