Hydraulic braking system and method for unmanned mining dump truck

Abstract

The invention discloses a hydraulic braking system and method for an unmanned mining dump truck. The hydraulic braking system comprises a service brake valve set and a parking brake valve set. The service brake valve group comprises a first hydraulic proportional pressure reducing valve, a second hydraulic proportional pressure reducing valve, a first shuttle valve and a first pressure sensor; the first hydraulic proportional pressure reducing valve and the second hydraulic proportional pressure reducing valve are connected in parallel; oil outlets of the first hydraulic proportional pressure reducing valve and the second hydraulic proportional pressure reducing valve are communicated with an oil inlet of a first shuttle valve; an oil outlet of the first shuttle valve is connected with a first pressure sensor; the parking brake valve group comprises an electromagnetic directional valve, a redundant electromagnetic directional valve and a pressure switch; the electromagnetic directional valve is a normally closed valve, and the redundant electromagnetic directional valve is a normally open valve; the electromagnetic directional valve and the redundant electromagnetic directional valve are connected in series, the electromagnetic directional valve is connected with an oil inlet pipeline, the redundant electromagnetic directional valve is connected with an oil outlet pipeline and a parking brake caliper, and a pressure switch is arranged on the oil outlet pipeline.

Description

Technical Field

[0001] This invention belongs to the field of unmanned mining dump trucks, specifically relating to a hydraulic braking system and method for an unmanned mining dump truck. Background Technology

[0002] Due to limitations in their axle structure, air-brake mining dump trucks are currently limited to models with a total load capacity of 100 tons or less. Mining dump trucks with a load capacity of over 100 tons require hydraulic brakes to meet the overall braking requirements. Hydraulic brakes can meet the braking needs of mining dump trucks with a load capacity of over 30 tons. With the increasing demand for driverless mining dump trucks, the need for hydraulic braking systems suitable for driverless operation has arisen.

[0003] The unmanned hydraulic braking system is the core of the safe operation of unmanned mining dump trucks. It must not only meet the reliability, rapid response and precise control capabilities of unmanned vehicles to cope with complex working conditions and harsh environments, but also achieve digitalization and intelligence, so as to empower smart mines with "digital hydraulics".

[0004] Currently, the braking systems of most unmanned mining dump trucks are improvements on the existing hydraulic braking systems of manually driven mining dump trucks, designed to respond to deceleration and parking commands issued by the unmanned driving control system under unmanned driving conditions. Specifically, see patent CN116901917 A, which discloses a commercial vehicle drive-by-wire redundant braking system and its control method. This patent's control system adds a drive-by-wire redundant braking unit to the existing braking control system. Specifically, the vehicle braking control system of this patent ultimately consists of a newly added electromagnetic proportional valve that forms redundancy with the mechanical valve in the same braking circuit as the conventional brake valve. The redundant braking unit is connected to the conventional brake valve via a shuttle valve, serving as a pilot air source to control the front axle single-channel bridge control module and the rear axle dual-channel bridge control module respectively. The problems with this braking control system are: 1. The two air outlets of the redundant braking unit are connected to the air inlet of the shuttle valve. 1. The mechanical brake valve assembly has two air outlets connected to the air inlets of two shuttle valves. The front axle single-channel bridge control module and the rear axle dual-channel bridge control module are connected to the air outlets of the two shuttle valves. This makes the piping complex and inconvenient for maintenance. 2. Redundancy between the redundant valve assembly and the conventional valve assembly results in poor system stability: The air-controlled shuttle valve has poor sealing stability. When the redundant braking unit is working, there is a high probability that high-pressure gas will enter the conventional brake valve through the shuttle valve. This can easily cause the redundant braking unit to be connected to the air outlet of the conventional brake valve. At this time, the air outlet and exhaust port of the conventional brake valve are connected, so it is impossible to establish pilot pressure, thus failing to control the bridge control module and causing redundancy failure.

[0005] Regarding the release of the parking brake on unmanned mining dump trucks, existing technology requires replacing the original hydraulic pilot handle control with an electronic parking switch, and replacing the hydraulic pilot-controlled parking valve with a hydraulic solenoid directional valve, enabling simultaneous manual and electronic parking functions. However, considering the safety of mining dump trucks, the entire vehicle must be in an effective parking state during unloading. In unmanned driving systems, the parking signal is linked to the lifting signal; if the unmanned driving control system does not receive a valid parking signal, it cannot issue a lifting command. If the parking solenoid valve becomes stuck or there is an electrical malfunction, the unmanned mining dump truck cannot be lifted, thus affecting the effective operation of the vehicle. Summary of the Invention

[0006] In order to solve the technical problems existing in the prior art, the present invention proposes a hydraulic braking system and control method for an unmanned mining dump truck.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a hydraulic braking system for an unmanned mining dump truck, including a service brake valve group and a parking brake valve group; The service brake valve assembly includes a first hydraulic proportional pressure reducing valve, a second hydraulic proportional pressure reducing valve, a first shuttle valve, and a first pressure sensor; the first hydraulic proportional pressure reducing valve and the second hydraulic proportional pressure reducing valve are connected in parallel; the oil outlets of the first hydraulic proportional pressure reducing valve and the second hydraulic proportional pressure reducing valve are connected to the oil inlet of the first shuttle valve, and the oil outlet of the first shuttle valve is connected to the first pressure sensor. The parking brake valve assembly includes a solenoid directional valve, a redundant solenoid directional valve, and a pressure switch; the solenoid directional valve is a normally closed valve, and the redundant solenoid directional valve is a normally open valve; the solenoid directional valve and the redundant solenoid directional valve are connected in series, the solenoid directional valve is connected to the oil inlet pipe, and the redundant solenoid directional valve is connected to the oil outlet pipe and the parking brake caliper, and a pressure switch is installed on the oil outlet pipe.

[0008] As a further technical solution, the service brake valve group and the pedal valve are connected in parallel and connected through a second shuttle valve.

[0009] As a further technical solution, the oil inlets of the service brake valve group, pedal valve, and parking brake valve group are connected to the same filling valve.

[0010] As a further technical solution, a vehicle accumulator and a pressure sensor are installed on the connecting pipeline between the filling valve and the service brake valve assembly.

[0011] As a further technical solution, a parking accumulator is installed on the connecting pipeline between the filling valve and the parking brake valve assembly.

[0012] As a further technical solution, a vehicle accumulator and a pressure sensor are installed on the connecting pipeline between the filling valve and the pedal valve.

[0013] As a further technical solution, the parking brake valve assembly is further connected in series with a pressure reducing valve at the front end of the electromagnetic directional valve.

[0014] As a further technical solution, the redundant electromagnetic directional valve and the second hydraulic proportional pressure reducing valve are both connected to the alarm system of the mining dump truck. After the redundant electromagnetic directional valve and the second hydraulic proportional pressure reducing valve are started, the alarm system of the mining dump truck is triggered.

[0015] As a further technical solution, the hydraulic braking system of the unmanned mining dump truck includes a hydraulic pump, which is connected to a filter and then to the filling valve.

[0016] Secondly, based on the aforementioned hydraulic braking system for unmanned mining dump trucks, the present invention also provides a control method, as detailed below: When the mining dump truck enters braking mode under unmanned driving conditions, the control system issues a deceleration command. The first pressure sensor collects the output pressure of the first hydraulic proportional pressure reducing valve in real time. If the difference between the collected pressure value and the set value exceeds the set range, it is determined that the first hydraulic proportional pressure reducing valve has failed. The control system then sends a braking signal to the second hydraulic proportional pressure reducing valve, which outputs braking pressure to ensure the reliability of braking performance. If the difference between the collected pressure value and the set value is within the set range, it is determined that the first hydraulic proportional pressure reducing valve is effective, and the second hydraulic proportional pressure reducing valve does not start. When the mining dump truck enters the parking release mode under unmanned driving conditions, the control system issues a parking release command, and the electromagnetic reversing valve is energized and opened to realize parking. If the electromagnetic reversing valve malfunctions during parking, the pressure switch receives a high-pressure signal and sends a signal to the overall control system. The vehicle control system then controls the redundant electromagnetic reversing valve to open and depressurize.

[0017] The beneficial effects of this invention are as follows: The mining dump truck proposed in this invention adds a redundant braking system directly to the pedal-type manual braking system. This braking system includes a first hydraulic proportional pressure reducing valve and a second hydraulic proportional pressure reducing valve, which are redundant with each other. That is, two proportional pressure reducing valves with equal functions (main brake + redundant brake) are connected via a hydraulic shuttle valve to ensure the reliability of the unmanned driving braking performance. Simultaneously, in the parking release system of this invention, a redundant electromagnetic directional valve is added. This ensures that if the parking solenoid valve becomes stuck when it is not energized, the pressure switch receives a high-pressure signal and sends a signal to the overall control system. The vehicle control system then controls the redundant electromagnetic directional valve to open, releasing pressure and keeping the dump truck in a parked state without affecting its normal lifting function, thus ensuring the reliability of the parking function. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the hydraulic braking system for the unmanned mining dump truck proposed in this invention; Figure 2 This is a schematic diagram of the service brake valve assembly in the hydraulic braking system proposed in this invention; Figure 3 This is a schematic diagram of the parking brake valve assembly in the hydraulic braking system proposed in this invention; In the diagram: 1 Hydraulic pump, 2 Filter, 3 Filling valve, 4 Service brake valve assembly, 5 Service accumulator, 6 Second pressure sensor, 7 Pedal valve, 8 Second shuttle valve, 9 Service brake caliper, 10 Relay valve, 11 Parking brake caliper, 12 Parking brake valve assembly, 13 Parking accumulator; 41 First hydraulic proportional pressure reducing valve, 42 Second hydraulic proportional pressure reducing valve, 43 First shuttle valve, 44 First pressure sensor; 121 Solenoid directional valve, 122 Pressure reducing valve, 123 Redundant solenoid directional valve, 124 Pressure switch, 125 Third pressure sensor; Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0019] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. To address the technical problems existing in the prior art, this invention proposes a hydraulic braking system and control method for an unmanned mining dump truck. Specifically, the hydraulic braking system of the unmanned mining dump truck mainly consists of a hydraulic pump 1, a filter 2, a filling valve 3, a service brake valve assembly 4, a service accumulator 5, a second pressure sensor 6, a pedal valve 7, a second shuttle valve 8, a service brake caliper 9, a relay valve 10, a parking brake caliper 11, a parking brake valve assembly 12, and a parking accumulator 13. The hydraulic pump 1 is connected to the filter 2 through a pipeline, and the filter 2 is connected to the filling valve 3. The filling valve 3 is connected to the service brake valve assembly 4, the pedal valve 7, a second shuttle valve 8, a service brake caliper 9, a relay valve 10, a parking brake caliper 11, a parking brake valve assembly 12, and a parking accumulator 13. The pedal valve 7 and the parking brake valve assembly 12 are connected. The pedal valve 7 and the service brake valve assembly 4 are connected in parallel via a second shuttle valve 8. The second shuttle valve 8 is connected to a relay valve 10, which in turn is connected to the parking brake caliper 9 on the vehicle. The parking brake valve assembly 12 is connected to the parking brake caliper 11. A service accumulator 5 and a second pressure sensor 6 are installed on the oil line connecting the filling valve 3 and the service brake valve assembly 4. A parking accumulator 13 is also installed on the connecting pipe between the filling valve 3 and the parking brake valve assembly 12. A service accumulator 5 and a second pressure sensor 6 are installed on the connecting pipe between the filling valve 3 and the pedal valve 7. The functions and specific structures of each component are explained below: Hydraulic pump 1 provides power to the hydraulic braking system. When the vehicle is driven by an engine, hydraulic pump 1 is driven by the engine. When the vehicle is driven by a new energy source, it is driven by an electric motor, forming an oil pump motor unit. It is used in conjunction with filling valve 3. The vehicle controller controls the start and stop of the oil pump motor unit according to the system pressure, realizing the automatic start and stop function of the oil pump motor unit and achieving energy saving effect.

[0020] Filter 2 is a high-pressure filter with a built-in clogging pressure alarm switch. When the filter impurities exceed the standard and cause the pressure alarm switch to sound, the whole vehicle will trigger a fault indication and the high-pressure filter element needs to be replaced.

[0021] The filling valve 3 is a dual-way filling valve, which can provide two oil sources with the same pressure and flow rate for the hydraulic service brake system, and also provide parking oil source for the hydraulic parking brake system; Two vehicle accumulators 5 are respectively connected to the two outlets of the dual-circuit filling valve 3. The vehicle accumulators 5 provide emergency oil supply for the vehicle braking system and eliminate pressure shocks in the braking system.

[0022] The two second pressure sensors 6 respectively feed back the pressure of the two hydraulic braking circuits to the vehicle controller.

[0023] The aforementioned pedal valve 7, service brake valve group 4, and shuttle valve 8 constitute the switching control logic for manned and unmanned driving, making the manned driving braking circuit and the unmanned driving braking circuit form a parallel structure. Specifically, the pedal valve 7 has two circuits, one of which connects to the outlet of the service brake valve group 4 and the two inlets of a shuttle valve; the other circuit connects to the outlet of the service brake valve group 4 and the two inlets of another shuttle valve, making the pedal valve 7 and service brake valve group 4 form a parallel system. The external control ports of the two relay valves 10 are respectively connected to the outlets of the two second shuttle valves 8. The opening of the relay valves 10 is controlled by the second shuttle valves 8, thereby controlling the flow of pressure oil between the relay valves 10 and the service brake caliper 9.

[0024] The parking accumulator 13 is connected to the long-term oil filling port to provide an emergency oil source for the parking brake system and eliminate pressure shocks in the parking brake system.

[0025] Furthermore, since the mining dump truck follows the "safety first" principle during unmanned operation, the hydraulic proportional pressure reducing valve has a "slide valve" structure. If the hydraulic braking system is not maintained in a timely manner, impurities in the hydraulic oil can cause occasional jamming of the proportional pressure reducing valve, leading to brake failure and compromising vehicle safety. Therefore, in this embodiment, while the first hydraulic proportional pressure reducing valve 41 meets the vehicle's performance requirements, a second hydraulic proportional pressure reducing valve 42 should be added for redundancy to improve the safety and reliability of the unmanned mining dump truck. Specifically, the service brake valve group 4 includes two sets of functionally identical first hydraulic proportional pressure reducing valves 41 and second hydraulic proportional pressure reducing valves 42; it also includes a first shuttle valve 43 and a first pressure sensor 44, which together form the control logic for the main brake and redundant brake. In this embodiment, the first hydraulic proportional pressure reducing valve 1-1 is used as the main brake valve, and the second hydraulic proportional pressure reducing valve 1-2 is used as the redundant brake valve for further explanation. See [link to documentation] for details. Figure 2 ; The inlet P and outlet T of the first hydraulic proportional pressure reducing valve 41 and the second hydraulic proportional pressure reducing valve 42 are connected through the internal oil passage of the valve block, realizing the "parallel" connection of the first hydraulic proportional pressure reducing valve 41 and the second hydraulic proportional pressure reducing valve 42; the outlet A of the first hydraulic proportional pressure reducing valve 41 and the second hydraulic proportional pressure reducing valve 42 are connected to the two inlet holes of the first shuttle valve 43 through the internal oil passage of the valve block, and the first pressure sensor 44 is connected to the outlet pipe of the first shuttle valve 43; when the mining dump truck is driving under unmanned driving conditions, the output pressure of the proportional valve corresponding to the deceleration command issued by the unmanned driving system is compared with the pressure fed back by the first pressure sensor 44. If the difference exceeds the set range, it is determined that the main brake valve (first hydraulic proportional pressure reducing valve 41) has failed, and at the same time, a braking signal is sent to the redundant brake valve (second hydraulic proportional pressure reducing valve 42). The redundant brake valve (second hydraulic proportional pressure reducing valve 42) outputs braking pressure to ensure the reliability of braking performance; the pressure sensor 44 collects the pressure at the outlet of the shuttle valve and sends it to the vehicle controller.

[0026] In this invention, two hydraulic proportional pressure reducing valves with the same function are redundant. That is, when one hydraulic proportional pressure reducing valve acts as the main braking valve, the other hydraulic proportional pressure reducing valve acts as a redundant braking valve. The service brake valve group 4 integrates the main braking and redundant braking functions, eliminating the need to connect to the main braking valve group in the existing dump truck. During the entire unmanned braking process, the first hydraulic proportional pressure reducing valve 41 simultaneously provides redundant braking pressure output to the front axle and the middle and rear axles. The second hydraulic proportional pressure reducing valve 42 does not work under normal circumstances. When the first hydraulic proportional pressure reducing valve 41 fails to brake due to jamming or other malfunctions, the second hydraulic proportional pressure reducing valve 42 immediately starts to provide redundant braking pressure output to the front axle and the middle and rear axles.

[0027] The first hydraulic proportional pressure reducing valve 41 and the second hydraulic proportional pressure reducing valve 42 can output different pressures according to the magnitude of the current signal, thereby realizing the linear output of the hydraulic braking force of the axle through the hydraulic proportional pressure reducing valves.

[0028] Furthermore, such as Figure 3 As shown, the parking brake valve assembly 12 in this embodiment includes an electromagnetic directional valve 121, a pressure reducing valve 122, a redundant electromagnetic directional valve 123, a pressure switch 124, and a pressure sensor 125. The electromagnetic directional valve 121, pressure reducing valve 122, redundant electromagnetic directional valve 123, pressure switch 124, and pressure sensor 125 constitute the control logic for the main parking brake and the redundant parking brake. Specifically, the pressure switch 124 provides a parking signal, feeding back the real-time parking status to the vehicle; the pressure sensor 125 detects the pressure in the real-time parking oil circuit. After the parking oil enters the valve block, it first passes through pressure reducing valve 2 to ensure that the pressure entering the parking solenoid valve is constant.

[0029] The P port of the solenoid directional valve 121 is connected to the filling valve 3 via a pipeline, and oil pressure is provided through the filling valve 3; the A port of the solenoid directional valve 121 is connected to the P port of the redundant solenoid directional valve 123; the T ports of both the solenoid directional valve 121 and the redundant solenoid directional valve 123 are connected to the return oil tank; the A port of the redundant solenoid directional valve 123 is connected to the parking brake caliper pipeline, wherein the T port is connected to the return oil tank separately and is not allowed to be combined with other return oil pipelines to ensure the reliability of valve operation.

[0030] The aforementioned parking brake caliper functions as a "fuel cut-off brake." When the solenoid directional valve 121 is not energized, its P port is closed, while its A port and T port are connected, essentially functioning as a normally closed valve. When the redundant solenoid directional valve 123 is not energized, its P port and A port are connected. Figure 2 This is a normally open valve, so when the vehicle is without power, there is no pressure in the parking brake caliper and it is in the "parking state"; When the vehicle needs to be released from parking, the solenoid directional valve 121 is energized and opens. Pressurized oil enters the redundant solenoid directional valve 123 through the P port of the solenoid directional valve 121 and then to the parking brake caliper. The parking brake caliper receives the set pressure, putting the vehicle in the "released parking state". During this process, the redundant solenoid directional valve 123 is not energized and remains in the unobstructed state. When the vehicle needs to be parked, the solenoid directional valve 121 needs to be de-energized. If there is jamming or loss of electrical signal at this time, and the pressure switch 124 does not receive a low-pressure signal, the vehicle control system controls the redundant solenoid directional valve 123 to open and depressurize, so that the dump truck is always parked and does not affect the normal lifting function of the dump truck. Once the redundant solenoid directional valve 123 is activated, it triggers the vehicle parking brake fault alarm. The back-end staff can make an assessment based on the actual situation and decide whether the faulty vehicle should continue to operate or be returned to the station for repair.

[0031] Pressure sensor 125 monitors the pressure in the oil circuit in real time. If the pressure in the oil circuit is greater or less than the set pressure value, it indicates that the solenoid directional valve 121 has not opened properly after being energized or that the redundant solenoid directional valve has malfunctioned. This triggers a vehicle parking brake fault alarm. The back-end staff can make an assessment based on the actual situation and decide whether the faulty vehicle should continue to operate or be returned to the station for repair.

[0032] To ensure vehicle safety, in autonomous driving mode, pressing the pedal valve automatically switches to manual driving mode, implementing a "manual priority" function. In manual driving mode, the service brake is controlled by the brake pedal, consistent with traditional vehicles; the parking brake is controlled by an electronic switch, replacing the traditional parking lever. In autonomous driving mode, when the vehicle starts from a standstill, it automatically enters parking mode; after sending an accelerator signal, the vehicle controller sends a signal to release the parking brake. In autonomous driving mode, the vehicle's tilt sensor can detect whether the vehicle is parked on a slope; if so, it automatically maintains braking force to prevent the vehicle from rolling, thus implementing a hill start assist function. In autonomous driving mode, when the control system detects an emergency, it automatically issues a maximum braking force command to all braking modules to ensure the shortest possible stopping distance, thus achieving emergency braking functionality.

[0033] During autonomous driving, the vehicle autonomous driving domain controller sends a deceleration command to the vehicle controller according to actual needs. The vehicle controller sends a current signal to the proportional pressure reducing valve in the service brake valve group according to the deceleration value. The proportional pressure reducing valve opens to a certain degree to deliver braking pressure to the service brake caliper, and the vehicle begins to brake.

[0034] Meanwhile, the pressure sensor in the service brake valve assembly feeds back the braking pressure to the vehicle controller. The vehicle controller compares the difference between the preset pressure and the feedback braking pressure. If the difference exceeds the set range, it determines that the main brake valve has failed and sends a braking signal to the redundant brake valve. The redundant brake valve outputs braking pressure to ensure the reliability of braking performance. After the redundant brake valve is activated, it triggers a vehicle service brake fault alarm. The back-end staff can make an assessment based on the actual situation and decide whether the faulty vehicle should continue to operate or be returned to the station for repair.

[0035] In this embodiment, the highly integrated service brake valve assembly and parking brake valve assembly are a single integrated valve assembly, which can reduce the amount of pipeline used and effectively reduce the possibility of hydraulic pipeline leakage.

[0036] In this embodiment, the automatic start-stop function of the motor pump in the new energy unmanned mining truck has a significant effect on reducing the energy consumption of the entire vehicle.

[0037] The high-pressure filter in this embodiment features a clogging alarm function, enabling intelligent detection of the hydraulic oil cleanliness in the hydraulic braking system. This allows for replacement of the filter element based on regular schedules, instead of replacement only upon alarm activation, effectively extending the hydraulic oil replacement cycle and reducing overall vehicle maintenance costs.

[0038] The driverless mining truck in this embodiment also has a ramp assist function: in driverless mode, the vehicle tilt sensor can detect whether it is stopped on a ramp. If it is on a ramp, it automatically maintains braking force to prevent the vehicle from sliding. The unmanned mining truck in this embodiment also has an emergency braking function: in unmanned driving mode, when the control system detects an emergency, the system automatically issues a maximum braking force command to ensure the shortest possible stop.

[0039] The unmanned mining truck in this embodiment also has the function of adding an accumulator to each braking branch to reduce the impact on the hydraulic system: when the hydraulic braking system is turned on and off, the sudden rise and fall of the system pressure can cause the pipeline and components to be subjected to a certain pressure impact, and the accumulator can absorb the impact.

[0040] In this embodiment, the driverless mining truck also features an accumulator added to each braking branch to replenish the oil supply, thereby improving the response speed of the braking system. The unmanned mining truck in this embodiment also has an accumulator added to each braking branch as an emergency power source: providing emergency braking force when the main pump fails.

Claims

1. A hydraulic braking system for an unmanned mining dump truck, comprising a service brake valve assembly and a parking brake valve assembly; characterized in that: The service brake valve assembly includes a first hydraulic proportional pressure reducing valve, a second hydraulic proportional pressure reducing valve, a first shuttle valve, and a first pressure sensor; the first hydraulic proportional pressure reducing valve and the second hydraulic proportional pressure reducing valve are connected in parallel; the oil outlets of the first hydraulic proportional pressure reducing valve and the second hydraulic proportional pressure reducing valve are connected to the oil inlet of the first shuttle valve, and the oil outlet of the first shuttle valve is connected to the first pressure sensor. The parking brake valve assembly includes a solenoid directional valve, a redundant solenoid directional valve, and a pressure switch; the solenoid directional valve is a normally closed valve, and the redundant solenoid directional valve is a normally open valve; the solenoid directional valve and the redundant solenoid directional valve are connected in series, the solenoid directional valve is connected to the oil inlet pipe, and the redundant solenoid directional valve is connected to the oil outlet pipe and the parking brake caliper, and a pressure switch is installed on the oil outlet pipe.

2. The hydraulic braking system for the unmanned mining dump truck as described in claim 1, characterized in that, The aforementioned service brake valve assembly is connected in parallel with the pedal valve and is connected through a second shuttle valve.

3. The hydraulic braking system for the unmanned mining dump truck as described in claim 1, characterized in that, The oil inlets of the service brake valve assembly, pedal valve, and parking brake valve assembly are connected to the same filling valve.

4. The hydraulic braking system for the unmanned mining dump truck as described in claim 3, characterized in that, A vehicle accumulator and a pressure sensor are installed on the connecting pipeline between the filling valve and the service brake valve assembly.

5. The hydraulic braking system for an unmanned mining dump truck as described in claim 3, characterized in that, A parking accumulator is installed on the connecting pipeline between the filling valve and the parking brake valve assembly.

6. The hydraulic braking system for an unmanned mining dump truck as described in claim 3, characterized in that, A vehicle accumulator and a pressure sensor are installed on the connecting pipe between the filling valve and the pedal valve.

7. The hydraulic braking system for an unmanned mining dump truck as described in claim 1, characterized in that, The parking brake valve assembly also has a pressure reducing valve connected in series at the front end of the solenoid directional valve.

8. The hydraulic braking system for an unmanned mining dump truck as described in claim 1, characterized in that, The redundant electromagnetic directional valve and the second hydraulic proportional pressure reducing valve are both connected to the alarm system of the mining dump truck. When the redundant electromagnetic directional valve and the second hydraulic proportional pressure reducing valve are activated, they trigger the alarm system of the mining dump truck.

9. The hydraulic braking system for an unmanned mining dump truck as described in claim 1, characterized in that, The hydraulic braking system of the unmanned mining dump truck includes a hydraulic pump, which is connected to a filter and then to a filling valve.

10. A control method for the hydraulic braking system of an unmanned mining dump truck according to any one of claims 1-9, characterized in that: When the mining dump truck enters braking mode under unmanned driving conditions, the control system issues a deceleration command. The first pressure sensor collects the output pressure of the first hydraulic proportional pressure reducing valve in real time. If the difference between the collected pressure value and the set value exceeds the set range, it is determined that the first hydraulic proportional pressure reducing valve has failed. The control system then sends a braking signal to the second hydraulic proportional pressure reducing valve, which outputs braking pressure to ensure the reliability of braking performance. If the difference between the collected pressure value and the set value is within the set range, it is determined that the first hydraulic proportional pressure reducing valve is effective, and the second hydraulic proportional pressure reducing valve does not start. When the mining dump truck enters the parking release mode under unmanned driving conditions, the control system issues a parking release command, and the electromagnetic reversing valve is energized and opened to realize parking. If the electromagnetic reversing valve malfunctions during parking, the pressure switch receives a high-pressure signal and sends a signal to the overall control system. The vehicle control system then controls the redundant electromagnetic reversing valve to open and depressurize.

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