Transportation vehicle and control system

Abstract

To provide a transportation vehicle and a control system, which can grasp the state of a travel road surface with a simple method.SOLUTION: A dump truck 1 includes: a traveling electric motor 17 which drives rear wheels 15; a steering device 20 which steers front wheels 16; an inverter 18 which detects an operation amount of the traveling electric motor 17; a steering angle sensor 22 which detects an operation amount of the steering device 20; and a control device 25 which calculates an operation amount of the traveling electric motor 17 for performing autonomous travel in accordance with a target route and target speed and the steering device 20 and performs travel control on the basis of the calculated operation amount. The control device 25 has a reference operation amount estimation section 27 for estimating a reference operation amount to be an operation amount of the steering device 20 when a travel road surface is in a reference state, an operation amount comparison section 28 for comparing the reference operation amount estimated by the reference operation amount estimation section 27 with the calculated operation amount of the steering device 20, and a road surface state determination section 29 for determining whether the travel road surface is more slippery than the reference state on the basis of a comparison result of the operation amount comparison section 28 and outputting the determination result.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Dump trucks, which are one type of transport vehicle, transport ore, etc., in mines, for example. To explain in detail, the dump truck loads ore, etc., at a loading site, travels along a transport path, and discharges the ore, etc., at a dump site. After that, the dump truck travels along the transport path to return to the loading site. The dump truck repeats this operation many times.

[0003] Patent Document 1 discloses a control device that transmits instructions regarding autonomous driving of a dump truck. The control device transmits a target route and a target speed to the dump truck. A control device mounted on the dump truck calculates the operation amount of the drive device and the steering device for autonomous driving according to the target route and the target speed, and performs driving control based on the calculated operation amount. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-157923 A Summary of the Invention [Problem to be solved by the invention]

[0005] For example, the transport volume per unit time is used as an index representing the work efficiency of the transport vehicle. According to this index, if the speed of the transport vehicle is increased, the work efficiency of the transport vehicle is improved. However, the speed of the transport vehicle is limited from the viewpoint of traveling safety. In particular, if the traveling road surface becomes slippery due to the influence of weather, the speed limit of the transport vehicle needs to be lowered. Therefore, in order to increase the work efficiency of the transport vehicle while ensuring the traveling safety of the transport vehicle, it is desirable to set the target speed of the transport vehicle after understanding the condition of the traveling road surface.

[0006] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a transport vehicle and a control system that are capable of grasping the condition of the road surface on which the vehicle is traveling in a simple manner. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, a representative aspect of the present invention is a transport vehicle equipped with a drive unit for driving the rear wheels, a steering unit for steering the front wheels, a detector for detecting the operation amounts of the drive unit and the steering unit, and a control unit for calculating the operation amounts of the drive unit and the steering unit for autonomous driving according to a target route and a target speed, and performing driving control based on the calculated operation amount, wherein the control unit has a reference operation amount estimation unit for estimating a reference operation amount which is the operation amount of at least one of the drive unit and the steering unit when the road surface being traveled is in a reference state, an operation amount comparison unit for comparing the reference operation amount estimated by the reference operation amount estimation unit with an operation amount of at least one of the drive unit and the steering unit which corresponds to the estimated reference operation amount and which has been calculated or detected by the detector, and a road surface condition determination unit for determining whether the road surface being traveled is more slippery than the reference state based on the comparison result of the operation amount comparison unit, and outputting the determination result. Effect of the Invention

[0008] According to the present invention, the condition of the road surface on which a vehicle is traveling can be grasped in a simple manner. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a configuration of a control system according to a first embodiment of the present invention. [Diagram 2] 1 is a side view illustrating a structure of a dump truck according to a first embodiment of the present invention. [Diagram 3] 1 is a block diagram showing equipment mounted on a dump truck in a first embodiment of the present invention. FIG. [Figure 4]FIG. 3 is a diagram showing a relationship between the steering angle of the front wheels of the dump truck and the lateral force of the front wheels in the first embodiment of the present invention. [Diagram 5] 5 is a flowchart showing a road surface condition determination process of the control device for the dump truck in the first embodiment of the present invention. [Figure 6] 10 is a flowchart showing a road surface condition determination process of a control device for a dump truck in a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A first embodiment of the present invention will be described with reference to the drawings.

[0011] Fig. 1 is a schematic diagram showing the configuration of a control system in this embodiment. Fig. 2 is a side view showing the structure of a dump truck in this embodiment. Fig. 3 is a block diagram showing equipment mounted on the dump truck in this embodiment.

[0012] The control system of this embodiment includes a plurality of dump trucks 1 that transport ore or the like in a mine, for example, and a control device 3 that can communicate with the plurality of dump trucks 1 via a communication device 2.

[0013] The control device 3 is a computer, and has, as functional configurations, a road surface condition storage unit 4, a target route setting unit 5, and a target speed setting unit 6. The control device 3 transmits to each dump truck 1 the target route (e.g., map data) set by the target route setting unit 5 and the target speed set by the target speed setting unit 6 (in detail, the target speed set for the entire target route, or a plurality of target speeds set for each of a plurality of sections into which the target route is divided).

[0014] The dump truck 1 includes a vehicle body frame 11, a loading platform 13 rotatably supported on the vehicle body frame 11 via a support shaft 12, a hoist cylinder 14 for rotating the loading platform 13, a plurality of rear wheels 15 attached to the rear side of the vehicle body frame 11, and a plurality of front wheels 16 attached to the front side of the vehicle body frame 11. The loading platform 13 carries ore, etc. Also, the loading platform 13 rotates about the support shaft 12 to discharge the ore, etc.

[0015] The dump truck 1 includes a traveling electric motor 17 that drives the rear wheels 15, an inverter 18 that detects and controls an operation amount (more specifically, braking / driving torque) of the traveling electric motor 17, and a speed sensor 19 that detects the speed of the dump truck 1. The inverter 18 detects and controls the braking / driving torque of the traveling electric motor 17 by detecting and controlling the power supplied to the traveling electric motor 17. The speed sensor 19 detects the speed of the dump truck 1 from the rotation speed of the rear wheels 15, for example.

[0016] The dump truck 1 includes a steering device 20 that steers the front wheels 16, a steering electric motor 21 that drives the steering device 20, and a steering angle sensor 22 that detects the amount of operation of the steering device 20 (specifically, the steering angle of the front wheels 16). Although not shown in detail, the steering device 20 is composed of, for example, a steering hydraulic cylinder that varies the steering angle of the front wheels 16, a steering control valve that controls the flow of pressure oil from a hydraulic pump to the steering hydraulic cylinder, and a shaft that is rotated by the steering electric motor 21 and operates the steering control valve.

[0017] The dump truck 1 includes a position measuring device 23 that measures the position and orientation of the vehicle itself. The position measuring device 23 measures the position and orientation of the vehicle itself based on signals from a plurality of satellites, for example.

[0018] The dump truck 1 includes a control device 25 capable of communicating with the control device 3 via a communication device 24. Although not shown in detail, the control device 25 includes a processor that executes processing according to a program, a memory that stores programs and data, etc. The control device 25 includes a travel control unit 26 as a functional configuration.

[0019] The travel control unit 26 of the control device 25 calculates the operation amount (more specifically, steering angle and braking / driving torque) of the steering device 20 and the traveling electric motor 17 for performing autonomous traveling according to the target route and the target speed received from the control device 3, and performs travel control based on the calculated operation amount. To explain in detail, the travel control unit 26 of the control device 25 calculates the steering angle of the steering device 20 based on the target route and the position and orientation measured by the position measurement device 23, and controls the steering device 20 via the steering electric motor 21 based on the calculated steering angle and the steering angle detected by the steering angle sensor 22. The travel control unit 26 of the control device 25 calculates the braking / driving torque (more specifically, positive driving torque or negative braking torque) of the traveling electric motor 17 based on the target speed and the speed measured by the speed sensor 19, and controls the traveling electric motor 17 via the inverter 18 based on the calculated braking / driving torque. In detail, the driving electric motor 17 is controlled to be driven in accordance with the calculated driving torque, or the driving electric motor 17 is controlled to be regeneratively driven in accordance with the calculated braking torque (in other words, the driving electric motor 17 is operated as a generator, and braking torque is generated by the rotational resistance).

[0020] A feature of this embodiment is that the control device 25 has a function of determining the condition of the road surface on which the dump truck 1 travels, based on the steering angle calculated by the travel control unit 26 (or the steering angle detected by the steering angle sensor 22 (detector)). This function will be explained using Fig. 4(a) and Fig. 4(b). Fig. 4(a) is a diagram showing the steering angle and lateral force of the front wheels in this embodiment, and Fig. 4(b) is a diagram showing the relationship between the steering angle of the front wheels and the lateral force of the front wheels.

[0021] 4(a), the steering angle θ of the front wheels 16 is the angle (slip angle) between the traveling direction A of the dump truck 1 and the rotation direction B of the front wheels 16. A lateral force F of the front wheels 16 is generated in response to the steering angle θ of the front wheels 16, and a rotational moment is generated by the lateral force F of the front wheels 16 (more specifically, its component FL in the lateral direction of the vehicle body), causing the dump truck 1 to turn.

[0022] As shown in Fig. 4(b), when the steering angle θ of the front wheels 16 is small, the lateral force F of the front wheels 16 is generated in approximately proportion thereto, and when the steering angle θ of the front wheels 16 is large, the lateral force F of the front wheels 16 becomes saturated. The lateral force F of the front wheels 16 changes according to the state of the road surface on which the vehicle is traveling. When the road surface is in a reference state, the lateral force F of the front wheels 16 changes as shown by the solid line in Fig. 4(b), and when the road surface is more slippery than the reference state, the lateral force F of the front wheels 16 changes as shown by the dashed line in Fig. 4(b).

[0023] For example, assume that a lateral force F1 of the front wheels 16 is required to turn the dump truck 1, and consider the steering angle of the front wheels 16 to obtain this. When the road surface is in a reference state, the steering angle of the front wheels 16 is θ1, but when the road surface is more slippery than the reference state, the steering angle of the front wheels 16 is θ2 (where θ2>θ1). Therefore, it is possible to determine the state of the road surface based on the steering angle θ of the front wheels 16.

[0024] Returning to FIG. 3 described above, the control device 25 further includes a reference operation amount estimating section 27, an operation amount comparing section 28, and a road surface condition determining section 29 as functional components.

[0025] The reference operation amount estimating unit 27 of the control device 25 estimates a reference steering angle of the steering device 20 as a reference operation amount which is an operation amount when the traveling road surface is in a reference state. The reference operation amount estimating unit 27 calculates the reference steering angle based on the traveling conditions (more specifically, the vehicle speed, the road surface gradient, the route curvature, etc.) every time the dump truck 1 moves.

[0026] Alternatively, the reference operation amount estimation unit 27 may acquire and store in advance the relationship between the position of the dump truck 1 and the reference steering angle, and read out the reference steering angle corresponding to the position measured by the position measurement device 23. That is, for example, in response to a command from the control device 3, it is recognized that the traveling road surface is in a reference state, and in that case, the steering angle calculated by the traveling control unit 26 or the steering angle detected by the steering angle sensor 22 is set as the reference steering angle, and is stored in advance in association with the position measured by the position measurement device 23. Then, the reference steering angle stored in advance may be read out according to the position measured by the position measurement device 23.

[0027] An operation amount comparison unit 28 of the control device 25 compares the steering angle calculated by the cruise control unit 26 (or the steering angle detected by the steering angle sensor 22) with the reference steering angle estimated by the reference operation amount estimation unit 27. The steering angle calculated by the cruise control unit 26 may be a value averaged over time.

[0028] The road surface condition determination unit 29 of the control device 25 determines whether the road surface is more slippery than the reference state based on the comparison result of the operation amount comparison unit 28. That is, when the steering angle calculated by the driving control unit 26 (or the steering angle detected by the steering angle sensor 22) is larger than the reference steering angle, it determines that the road surface is more slippery than the reference state, and when the steering angle calculated by the driving control unit 26 (or the steering angle detected by the steering angle sensor 22) is smaller than the reference steering angle, it determines that the road surface is in the reference state. Note that the road surface may be determined to be more slippery than the reference state when the steering angle calculated by the driving control unit 26 (or the steering angle detected by the steering angle sensor 22) continues to be larger than the reference steering angle for a certain period of time.

[0029] Next, the road surface condition determination process of the control device 25 of the dump truck 1 in this embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing the road surface condition determination process of the control device of the dump truck in this embodiment.

[0030] In step S1, the control device 25 of the dump truck 1 acquires the position of the vehicle measured by the position measuring device 23.

[0031] Then, the process proceeds to step S2, where the operation amount comparison unit 28 of the control device 25 of the dump truck 1 compares the steering angle calculated by the traveling control unit 26 (or the steering angle detected by the steering angle sensor 22) with the reference steering angle estimated by the reference operation amount estimation unit 27. The road surface condition determination unit 29 of the control device 25 of the dump truck 1 determines whether the traveling road surface is more slippery than the reference state based on the comparison result of the operation amount comparison unit 28.

[0032] Then, the process proceeds to step S3, where the road surface condition determination unit 29 of the control device 25 of the dump truck 1 outputs the state of the traveling road surface determined in step S2 in association with the position acquired in step S1. That is, the control device 25 of the dump truck 1 transmits the determined state of the traveling road surface to the control device 3 in association with the position.

[0033] The road surface condition storage unit 4 of the control device 3 stores the state of the traveling road surface and its position received from the dump truck 1. The target route setting unit 5 and target speed setting unit 6 of the control device 3 set a target route and target speed for each dump truck 1 based on the state of the traveling road surface and its position stored in the road surface condition storage unit 4. In other words, for positions of the traveling road surface that are more slippery than the reference state, the target speed is set lower, or the target route is set to avoid those positions.

[0034] As described above, in this embodiment, the state of the traveling road surface can be grasped by using information obtained by the autonomous traveling control of the dump truck 1. Therefore, the state of the traveling road surface can be grasped by a simple method without requiring a dedicated sensor for measuring the state of the traveling road surface.

[0035] A second embodiment of the present invention will be described below. In this embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0036] In this embodiment, the control device 25 has a function of determining the state of the road surface on which the dump truck 1 travels based on the control driving torque (specifically, positive driving torque or negative braking torque) calculated by the travel control unit 26. In explaining this function, for example, assume the acceleration required for the dump truck 1 and consider the driving torque required to obtain this acceleration. When the driving road surface is in the reference state (in other words, the slip ratio of the wheels is low), the driving torque is D1, but when the driving road surface is more slippery than the reference state (in other words, the slip ratio of the wheels is high), the driving torque is D2 (where D2 > D1). Also, for example, assume the deceleration required for the dump truck 1 and consider the braking torque required to obtain this deceleration. When the driving road surface is in the reference state (in other words, the slip ratio of the wheels is low), the braking torque is B1, but when the driving road surface is more slippery than the reference state (in other words, the slip ratio of the wheels is high), the driving torque is B2 (where B2 < B1). Therefore, it is possible to determine the state of the driving road surface based on the control driving torque.

[0037] The reference operation amount estimation unit 27 of the control device 25 stores the reference control driving torque (specifically, positive reference driving torque and negative reference braking torque) of the traveling electric motor 17 as the reference operation amount, which is the operation amount when the traveling road surface is in the reference state. The reference operation amount estimation unit 27 calculates the reference control driving torque based on the traveling conditions every time the dump truck 1 moves.

[0038] Alternatively, the reference operation amount estimation unit 27 may, for example, acquire and store in advance the relationship between the position of the dump truck 1 and the reference control driving torque, and read out the reference control driving torque corresponding to the position measured by the position measuring device 23. That is, based on the command from the control device 3, it is recognized that the traveling road surface is in the reference state, and the control driving torque calculated by the travel control unit 26 in that case is used as the reference control driving torque and stored in advance in association with the position measured by the position measuring device 23. Then, the reference control driving torque stored in advance may be read out according to the position measured by the position measuring device 23.

[0039] The operation amount comparison unit 28 of the control device 25 compares the braking / driving torque calculated by the driving control unit 26 with the reference braking / driving torque estimated by the reference operation amount estimation unit 27. The braking / driving torque calculated by the driving control unit 26 may be a time-series averaged value.

[0040] The road surface condition determination unit 29 of the control device 25 determines whether the road surface is more slippery than the reference state based on the comparison result of the operation amount comparison unit 28. That is, when the driving torque calculated by the driving control unit 26 is larger than the reference driving torque, the road surface is determined to be more slippery than the reference state, and when the driving torque calculated by the driving control unit 26 is smaller than the reference driving torque, the road surface is determined to be in the reference state. When the braking torque calculated by the driving control unit 26 is smaller than the reference braking torque, the road surface is determined to be in the reference state. When the braking torque calculated by the driving control unit 26 is larger than the reference braking torque, the road surface is determined to be in the reference state. Note that the road surface may be determined to be more slippery than the reference state when the driving torque calculated by the driving control unit 26 is larger than the reference driving torque for a certain period of time. The road surface may be determined to be more slippery than the reference state when the braking torque calculated by the driving control unit 26 is smaller than the reference braking torque for a certain period of time.

[0041] Next, the road surface condition determination process of the control device 25 of the dump truck 1 in this embodiment will be described with reference to Fig. 6. Fig. 6 is a flowchart showing the road surface condition determination process of the control device of the dump truck in this embodiment.

[0042] In step S1, the control device 25 of the dump truck 1 acquires the position of the vehicle measured by the position measuring device 23.

[0043] Thereafter, the process proceeds to step S4, where the operation amount comparison unit 28 of the control device 25 of the dump truck 1 compares the braking / driving torque calculated by the traveling control unit 26 with the reference braking / driving torque estimated by the reference operation amount estimation unit 27. The road surface condition determination unit 29 of the control device 25 of the dump truck 1 determines whether the traveling road surface is more slippery than the reference condition, based on the comparison result of the operation amount comparison unit 28.

[0044] Then, the process proceeds to step S3, where the road surface condition determination unit 29 of the control device 25 of the dump truck 1 outputs the state of the traveling road surface determined in step S4 in association with the position acquired in step S1. That is, the control device 25 of the dump truck 1 transmits the determined state of the traveling road surface to the control device 3 in association with the position.

[0045] As described above, in this embodiment, the state of the traveling road surface can be grasped by using information obtained by the autonomous traveling control of the dump truck 1. Therefore, the state of the traveling road surface can be grasped by a simple method without requiring a dedicated sensor for measuring the state of the traveling road surface.

[0046] In the first embodiment, the control device 25 determines whether the road surface is more slippery than the reference state based on the comparison result between the steering angle of the steering device 20 and the reference steering angle, and in the second embodiment, the control device 25 determines whether the road surface is more slippery than the reference state based on the comparison result between the braking / driving torque of the traveling electric motor 17 (drive device) and the reference braking / driving torque, but the present invention is not limited to this. The control device 25 may determine whether the road surface is more slippery than the reference state based on the comparison result between the steering angle of the steering device 20 and the reference steering angle, and may determine whether the road surface is more slippery than the reference state based on the comparison result between the braking / driving torque of the traveling electric motor 17 and the reference braking / driving torque. Then, based on the comparison result between the steering angle of the steering device 20 and the reference steering angle, it may be determined that the road surface is more slippery than the reference state, or based on the comparison result between the braking / driving torque of the traveling electric motor 17 and the reference braking / driving torque, it may be determined that the road surface is more slippery than the reference state.

[0047] In addition, in the first and second embodiments, the control device 25 has been described as determining whether the road surface is more slippery than the reference state based on the comparison result between the operation amount and the reference operation amount, but the slipperiness of the road surface may be further evaluated depending on the magnitude of the difference between the operation amount and the reference operation amount.

[0048] In the first and second embodiments, the dump truck 1 has been described as having a regenerative brake (i.e., the control device 25 regeneratively controls the traveling electric motor 17 in accordance with the calculated braking torque), but this is not limiting. The dump truck 1 may have a hydraulic brake. In other words, the control device 25 may drive and control the hydraulic brake in accordance with the calculated braking torque.

[0049] In the first and second embodiments, the dump truck 1 has only the function of autonomously traveling according to the target route and the target speed received from the control device 3, but is not limited to this. In addition to the above-mentioned functions, the dump truck 1 may have a function of traveling by the driver's operation, and one of the functions may be selectable.

[0050] In the first and second embodiments, the transport vehicle to which the present invention is applied is described as a dump truck, but the present invention is not limited to this. The present invention may be applied to transport vehicles other than dump trucks. [Explanation of symbols]

[0051] 1. Dump truck 3 Control device 15 Rear wheel 16 Front wheel 17 Electric motor for driving (drive unit) 18 Inverter (detector) 20 Steering Gear 22 Steering angle sensor (detector) 25 Control device 27 Standard manipulated variable estimator 28 Manipulated amount comparison section 29 Road surface condition determination unit

Claims

1. A drive unit that drives the rear wheels, a steering unit that steers the front wheels, a detector for detecting an operation amount of the drive device and the steering device; A transport vehicle including a control device that calculates operation amounts of the drive device and the steering device for autonomous driving according to a target route and a target speed, and performs driving control based on the calculated operation amounts, The control device includes: a reference operation amount estimating unit that estimates a reference operation amount which is an operation amount of at least one of the drive device and the steering device when a traveling road surface is in a reference state; an operation amount comparison unit that compares the reference operation amount estimated by the reference operation amount estimation unit with an operation amount of at least one of the drive device and the steering device, the operation amount corresponding to the estimated reference operation amount and calculated or detected by the detector; a road surface condition determination unit that determines whether the road surface is more slippery than the reference condition based on a comparison result of the operation amount comparison unit, and outputs the determination result.

2. 2. The transport vehicle according to claim 1, the reference operation amount estimating unit estimates a reference steering angle of the steering device as a reference operation amount; The transport vehicle, wherein the operation amount comparison unit compares the steering angle of the steering device calculated or detected by the detector with the reference steering angle estimated by the reference operation amount estimation unit.

3. 2. The transport vehicle according to claim 1, The reference operation amount estimating unit estimates a reference braking / driving torque of the drive device as a reference operation amount, The transport vehicle, wherein the operation amount comparison unit compares the calculated braking / driving torque of the drive device with the reference braking / driving torque estimated by the reference operation amount estimation unit.

4. 2. The transport vehicle according to claim 1, The transport vehicle, wherein the reference operation amount estimating unit calculates the reference operation amount based on a traveling condition.

5. 2. The transport vehicle according to claim 1, The transport vehicle, wherein the reference operation amount estimating unit stores the operation amount calculated or detected by a detector when the traveling road surface is in the reference state as a reference operation amount.

6. A control device that transmits a target route and a target speed; and a transport vehicle equipped with a control device that receives the target route and the target speed, calculates operation amounts for a drive device and a steering device for autonomous driving according to the target route and the target speed, and controls the drive device and the steering device based on the calculated operation amounts to perform driving control. The control device of the transport vehicle includes: a reference operation amount estimating unit that estimates a reference operation amount, which is the operation amount of at least one of the drive device and the steering device when a traveling road surface is in a reference state; an operation amount comparison unit that compares the reference operation amount estimated by the reference operation amount estimation unit with an operation amount of at least one of the drive device and the steering device, the operation amount corresponding to the estimated reference operation amount and calculated or detected by a detector of the transport vehicle; a road surface condition determination unit that determines whether the road surface is more slippery than the reference condition based on the comparison result of the operation amount comparison unit, and outputs the determination result; The control device includes: A control system, comprising: a control unit for controlling a vehicle speed based on a result of a determination made by the road surface condition determining unit;

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