Hydrostatic bulldozer hydraulic braking system and control method

Abstract

The hydraulic braking system of the static hydraulic bulldozer and the control method comprise a hydraulic source, a main oil supply branch, a standby oil supply branch, a brake oil circuit, a brake, a brake pressure sensor, a standby pressure sensor and a controller; the main oil supply branch and the standby oil supply branch are communicated with the hydraulic source; the main oil supply branch and the standby oil supply branch are also communicated with the brake oil circuit; the brake oil circuit is communicated with the brake; the brake pressure sensor is used for acquiring the oil pressure in the brake oil circuit; the standby pressure sensor is used for acquiring the oil pressure in the standby oil supply branch; the controller is used for controlling the standby oil supply branch to be connected when the oil pressure in the brake oil circuit is lower than a set oil pressure boundary value and lasts for a set time; then, the reason for the excessively low oil pressure in the brake oil circuit is determined according to the oil pressure in the brake oil circuit and the oil pressure in the standby oil supply branch. The reliable operation of the bulldozer braking system is ensured, and the reason for the monitored excessively low brake pressure can be located.

Description

Technical Field

[0001] This invention relates to the field of bulldozer braking control technology, and in particular to a hydrostatic bulldozer hydraulic braking system and control method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] The hydrostatic bulldozer's braking system is a continuously closed braking system, meaning the system is in a braking state when there is no pressure in the brake. Under the set braking pressure, the brake opens, releasing the machine, after which it can move normally. If the bulldozer operates with a braking pressure lower than the set value, the brake friction pads will wear, leading to braking failure.

[0004] In actual use, sensors are added to the brake clutch line to monitor the brake pressure. However, due to the harsh working conditions of bulldozers, the sensors are prone to failure and cannot fully and accurately reflect the brake system pressure. The accuracy of intelligent diagnosis is not high, and the failure rate is still relatively high. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a hydrostatic bulldozer hydraulic braking system and control method, which can accurately determine the cause of excessively low monitored braking pressure and implement corresponding control measures to ensure reliable operation of the braking system.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In the first aspect, a hydrostatic bulldozer hydraulic braking system is proposed, including: a hydraulic source, a main oil supply branch, a backup oil supply branch, a braking oil circuit, a brake, a braking pressure sensor, a backup pressure sensor, and a controller. Both the main oil supply branch and the backup oil supply branch are connected to the hydraulic power source; both the main oil supply branch and the backup oil supply branch are also connected to the brake oil circuit; the brake oil circuit is connected to the brake. Brake pressure sensor is used to obtain the oil pressure in the brake fluid circuit; A backup pressure sensor is used to obtain the oil pressure in the backup oil supply branch; The controller is used to activate the backup oil supply branch when the oil pressure in the brake oil circuit is lower than the set oil pressure threshold value and remains so for a set time. Then, it determines the cause of the low oil pressure in the brake oil circuit based on the oil pressure in the brake oil circuit and the oil pressure in the backup oil supply branch.

[0007] Furthermore, the controller is used to determine that the low oil pressure in the brake circuit is caused by a blockage in the main oil supply branch when both the oil pressure in the brake circuit and the oil pressure in the backup oil supply branch are higher than the set oil pressure threshold; when the oil pressure in the brake circuit is lower than the set oil pressure threshold, but the oil pressure in the backup oil supply branch is higher than the set oil pressure threshold, the controller determines that the low oil pressure in the brake circuit is caused by a damaged brake pressure sensor; and when both the oil pressure in the brake circuit and the oil pressure in the backup oil supply branch are lower than the set oil pressure threshold, the controller determines that the low oil pressure in the brake circuit is caused by low brake pressure.

[0008] Furthermore, the controller is also used to activate the active braking protection strategy when the reason for the low oil pressure in the brake oil circuit is determined to be the low braking pressure of the brake.

[0009] Furthermore, the controller is also used to control the vehicle's gear position not to exceed a set gear when the oil pressure in the backup fuel supply branch is lower than a set oil pressure threshold and higher than a first oil pressure threshold, and the duration exceeds a set time threshold, after the active braking protection strategy is activated; to control the engine speed to drop to idle speed when the oil pressure in the backup fuel supply branch is lower than the first oil pressure threshold and higher than a second oil pressure threshold, and the duration exceeds a set time threshold; and to control the bulldozer to brake and stop when the oil pressure in the backup fuel supply branch is lower than the second oil pressure threshold, and the duration exceeds a set time threshold.

[0010] Furthermore, solenoid valves are installed in both the main fuel supply branch and the backup fuel supply branch. The controller controls the connection or disconnection of the main fuel supply branch and the backup fuel supply branch by controlling the opening and closing of the solenoid valves.

[0011] Furthermore, the controller and display device are connected in communication. The controller is used to generate alarm information based on the cause of low oil pressure in the brake fluid circuit; The display device is used to display alarm information.

[0012] Furthermore, the hydraulic source includes a hydraulic pump and a hydraulic oil tank; one end of the hydraulic pump is connected to the hydraulic oil tank, and the other end of the hydraulic pump is connected to the oil supply pipe, which is connected to both the main oil supply branch and the backup oil supply branch.

[0013] Furthermore, an overflow valve is installed on the oil supply line.

[0014] Secondly, a control method for the hydraulic braking system of a hydrostatic bulldozer is proposed, including: When the brake is supplied with oil only through the main oil supply branch, the oil pressure in the brake oil circuit is obtained; When the oil pressure in the brake oil circuit is lower than the set oil pressure threshold and remains so for a set time, the backup oil supply branch is activated. Obtain the oil pressure in the backup oil supply branch; Determine the cause of low brake fluid pressure based on the oil pressure in the brake fluid circuit and the oil pressure in the backup oil supply branch.

[0015] Thirdly, a computer device is proposed, the device comprising: A processor, adapted to execute computer programs; A computer-readable storage medium storing a computer program, which, when executed by the processor, implements a control method for a hydrostatic bulldozer hydraulic braking system as proposed in the second aspect.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention proposes a hydrostatic bulldozer hydraulic braking system and control method. The system has two brake oil supply lines: a main oil supply line and a backup oil supply line. When the bulldozer is fault-free, the main oil supply line supplies oil to the brake. The oil pressure in the brake oil circuit, obtained by a brake pressure sensor, represents the braking pressure. When the oil pressure in the brake oil circuit is lower than a set oil pressure threshold and remains below it for a set time, it indicates that the monitored braking pressure is too low. At this time, the backup oil supply line is connected to supplement the brake with oil to ensure reliable brake operation. Furthermore, the cause of the low brake oil pressure can be determined based on the oil pressure in the brake oil circuit and the oil pressure in the backup oil supply line.

[0017] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0019] Figure 1 This is a schematic diagram of a hydrostatic bulldozer hydraulic braking system proposed in an embodiment of the present invention; Figure 2 This is a control logic diagram of a hydrostatic bulldozer hydraulic braking system proposed in an embodiment of the present invention.

[0020] The components include: 1. Hydraulic oil tank, 2. Hydraulic pump, 3. Filter, 4. Solenoid valve, 5. Solenoid valve, 6. Backup pressure sensor, 7. Shuttle valve, 8. Brake pressure sensor, 9. Controller, 10. Instrument, 11. Brake, 12. Relief valve. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0023] 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 exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. 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.

[0024] In this invention, terms such as "fixed connection," "connected," and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this invention based on the specific circumstances, and they should not be construed as limitations on the invention.

[0025] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0026] To ensure the reliable operation of the bulldozer's braking system and accurately pinpoint the cause of excessively low braking pressure, this invention proposes a hydrostatic bulldozer hydraulic braking system, such as... Figure 1 , Figure 2 As shown, it includes: a hydraulic power source, a main oil supply branch, a backup oil supply branch, a brake oil circuit, a brake 11, a brake pressure sensor 8, a backup pressure sensor 6, and a controller 9. Both the main oil supply branch and the backup oil supply branch are connected to the hydraulic power source; both the main oil supply branch and the backup oil supply branch are also connected to the brake oil circuit; the brake oil circuit is connected to the brake 11; Brake pressure sensor 8 is used to obtain the oil pressure in the brake fluid circuit; Backup pressure sensor 6 is used to obtain the oil pressure in the backup oil supply branch; The controller 9 is used to control the backup oil supply branch to be turned on when the oil pressure in the brake oil circuit is lower than the set oil pressure threshold value and continues for a set time; then, based on the oil pressure in the brake oil circuit and the oil pressure in the backup oil supply branch, the reason for the low oil pressure in the brake oil circuit is determined.

[0027] The hydraulic source includes a hydraulic pump 2 and a hydraulic oil tank 1; one end of the hydraulic pump 2 is connected to the hydraulic oil tank 1, and the other end of the hydraulic pump 2 is connected to the oil supply pipe, which is connected to both the main oil supply branch and the backup oil supply branch.

[0028] An overflow valve 12 is installed on the oil supply pipe to ensure the stability of the hydraulic oil pressure output by the hydraulic source.

[0029] In addition, a filter 3 is installed on the oil supply pipe. The hydraulic oil in the oil supply pipe is filtered by the filter 3 before entering the main oil supply branch and the backup oil supply branch, ensuring that there are no impurities in the hydraulic oil in each branch.

[0030] Solenoid valves are installed in both the main fuel supply branch and the backup fuel supply branch. The controller controls the connection or disconnection of the main fuel supply branch and the backup fuel supply branch by controlling the opening and closing of the solenoid valves.

[0031] Specifically, one end of the main oil supply branch and one end of the backup oil supply branch are connected to the oil supply pipe, and the other end of the main oil supply branch and the other end of the backup oil supply branch are connected to the shuttle valve 7. The shuttle valve 7 is also connected to the brake oil circuit.

[0032] Among them, shuttle valve 7 is a three-way valve, with the main oil supply branch, the backup oil supply branch and the brake oil line connected to the three valve ports of shuttle valve 7 respectively.

[0033] like Figure 1 As shown, a solenoid valve 4 is installed in the main oil supply branch. When the solenoid valve 4 is energized, the main oil supply branch is connected. When the solenoid valve 4 is de-energized, the main oil supply branch is not connected. A solenoid valve 5 is installed in the backup oil supply branch. When the solenoid valve 5 is energized, the backup oil supply branch is connected. When the solenoid valve 5 is de-energized, the backup oil supply branch is not connected.

[0034] In this embodiment of the invention, after the backup fuel supply branch is connected, the controller further determines the cause of the low fuel pressure in the brake circuit based on the fuel pressure in the brake circuit and the fuel pressure in the backup fuel supply branch. Specifically: The controller is used to determine that the low oil pressure in the brake circuit is caused by a blockage in the main oil supply branch when both the oil pressure P1 in the brake circuit and the oil pressure P2 in the backup oil supply branch are higher than the set oil pressure threshold P0; when the oil pressure P1 in the brake circuit is lower than the set oil pressure threshold P0, while the oil pressure P2 in the backup oil supply branch is higher than the set oil pressure threshold P0, the low oil pressure in the brake circuit is caused by a damaged brake pressure sensor; when both the oil pressure P1 in the brake circuit and the oil pressure P2 in the backup oil supply branch are lower than the set oil pressure threshold P0, the low oil pressure in the brake circuit is caused by low brake pressure.

[0035] Specifically, the sticking problem in the main oil supply branch refers to the sticking problem of solenoid valve 4 in the main oil supply branch.

[0036] The controller is also used to activate the active brake protection strategy when the reason for low oil pressure in the brake circuit is determined to be low brake pressure.

[0037] The controller is also used to control the vehicle's gear position not to exceed a set gear when the oil pressure P2 in the backup fuel supply branch is lower than the set oil pressure threshold P0 and higher than the first oil pressure threshold P3 for a duration exceeding a set time threshold after the active braking protection strategy is activated; to control the engine speed to drop to idle speed when the oil pressure P2 in the backup fuel supply branch is lower than the first oil pressure threshold P3 and higher than the second oil pressure threshold P4 for a duration exceeding a set time threshold; and to control the bulldozer to brake and stop when the oil pressure P2 in the backup fuel supply branch is lower than the second oil pressure threshold P4 for a duration exceeding a set time threshold.

[0038] The first oil pressure threshold P3 is preferably 0.85P0; the second oil pressure threshold P4 is preferably 0.75P0. The gear setting is 4 gears.

[0039] By controlling the control current of the travel pump to not exceed I01, the output flow of the travel pump is limited to be lower than the set flow; and the travel motor is controlled to work at the maximum current, limiting the vehicle's gears to no more than 4.

[0040] When the vehicle is brought to a stop, the travel pump control current is first reduced to 0, and the brake solenoid valve is de-energized, thereby stopping the bulldozer from operation and actively protecting the brakes.

[0041] The controller in this embodiment of the invention is also communicatively connected to the display device; The controller is used to generate alarm information based on the cause of low oil pressure in the brake fluid circuit; The display device is used to display alarm information.

[0042] The display device can be instrument 10, which displays the alarm information.

[0043] Specifically, when the low oil pressure in the brake fluid circuit is caused by a blockage in the main oil supply branch, the generated alarm message is "Solenoid valve 4 is stuck, the backup braking system has been activated"; when the low oil pressure in the brake fluid circuit is caused by a damaged brake pressure sensor 8, the generated alarm message is "Brake pressure sensor 8 is damaged, please replace it in time"; when the low oil pressure in the brake fluid circuit is caused by a low brake pressure, the generated alarm message is "Low brake pressure, active brake protection measures will be activated soon".

[0044] The working process of a hydrostatic bulldozer hydraulic braking system proposed in this embodiment of the invention is as follows: Figure 2 As shown, it includes: During normal operation, solenoid valve 4 is energized and solenoid valve 5 is de-energized, connecting the main oil supply branch and disconnecting the standby oil supply branch. The hydraulic pump 2 outputs oil that passes sequentially through filter 3, solenoid valve 4, and shuttle valve 7 before entering brake 11. Brake pressure sensor 8 detects the oil pressure in the brake circuit, which is the brake pressure. The detected brake pressure value is input to controller 11 and displayed on instrument 10.

[0045] The brake pressure sensor 8 inputs the brake pressure value of the controller and compares it with the set oil pressure threshold P0 in real time. When the brake pressure value detected by the brake pressure sensor 8 is lower than the set oil pressure threshold P0, and after a duration of t, the solenoid valve 5 is energized and the backup oil supply branch is connected.

[0046] The pressure values ​​detected by the backup pressure sensor 6 and the brake pressure sensor 8 are simultaneously input to the controller. The two input pressures are compared with the set oil pressure threshold P0. If the input values ​​of both sensors are higher than the set oil pressure threshold P0, the instrument displays the alarm message "Solenoid valve 4 is stuck, backup oil supply branch has been activated".

[0047] If the input value of the backup pressure sensor 6 is higher than the set oil pressure threshold P0, and the input value of the brake pressure sensor 8 is lower than the set oil pressure threshold P0, the instrument will display the alarm message "Brake pressure sensor 8 is damaged, please replace it in time," and the solenoid valve 5 will continue to be energized until the entire machine shuts down.

[0048] If the input values ​​of both sensors are lower than the set oil pressure threshold P0, the instrument will display the alarm message "Low brake pressure, active brake protection measures will be activated soon".

[0049] Active Braking Protection: When both solenoid valves 4 and 5 are energized, the instrument displays the alarm message "Low brake pressure, active braking protection measures will be activated soon" t1. Active braking protection then begins, controlled based on the input value of the backup pressure sensor 6. When the oil pressure detected by the backup pressure sensor 6 is within the range of (0.85-1)P0 and remains within this range for t1, the controller outputs a command to ensure the travel pump control current does not exceed I01, and the travel motor operates at its maximum current, thereby controlling the vehicle's gear position to not exceed 4. When the oil pressure detected by the backup pressure sensor 6 is within the range of (0.75-1)P0 and remains within this range for t1, the engine speed is reduced to idle speed to limit power. When the oil pressure detected by the backup pressure sensor 6 is below 0.75P0 and remains below this range for t1s, rapid braking is initiated from the engine idle speed, reducing the travel pump control current to zero, de-energizing the brake solenoid valve, stopping the bulldozer, and actively protecting the brakes.

[0050] This invention proposes a hydrostatic bulldozer hydraulic braking system. When the main oil supply line supplies oil to the brakes, resulting in excessively low braking pressure, a backup oil supply line is activated. By comparing the input values ​​of both the brake pressure sensor and the backup pressure sensor with set values, the system intelligently determines the cause of the low braking pressure and implements corresponding control measures to ensure reliable operation of the braking system. Once the braking pressure is indeed lower than the set oil pressure threshold, the braking system actively reduces the operating speed based on the overall machine operating status, and if necessary, forces a shutdown, providing active protection and safeguarding the brakes. This system offers the following advantages: (1) It can determine the authenticity of the brake pressure warning and accurately give the cause of the fault and suggestions.

[0051] (2) If the brake pressure fails, the backup oil supply branch will be automatically started to supply oil to the brake, which will not affect the normal operation of the whole machine and ensure the stable and reliable operation of the brake.

[0052] (3) After both the main fuel supply branch and the backup fuel supply branch fail, the braking system is actively protected by controlling components such as gear position and engine to maximize the safety of the brake.

[0053] This invention also proposes a control method for a hydrostatic bulldozer hydraulic braking system, comprising: When the brake is supplied with oil only through the main oil supply branch, the oil pressure in the brake oil circuit is obtained; When the oil pressure in the brake oil circuit is lower than the set oil pressure threshold and remains so for a set time, the backup oil supply branch is activated. Obtain the oil pressure in the backup oil supply branch; Determine the cause of low brake fluid pressure based on the oil pressure in the brake fluid circuit and the oil pressure in the backup oil supply branch.

[0054] It should be noted that the control method of the hydrostatic bulldozer hydraulic braking system provided in the above embodiment and the embodiment of the hydrostatic bulldozer hydraulic braking system belong to the same concept. The specific implementation process can be found in the system embodiment, and will not be repeated here.

[0055] The present invention also discloses a computer device, the device comprising: A processor, adapted to execute computer programs; A computer-readable storage medium storing a computer program, which, when executed by the processor, implements a control method for a hydrostatic bulldozer hydraulic braking system disclosed in an embodiment of the present invention.

[0056] The computer device can be a portable mobile terminal, such as a smartphone, tablet, laptop, or desktop computer. Typically, a computer device includes a processor and memory.

[0057] A processor may include one or more processing cores, such as a core processor or a core processor. The processor may be implemented using at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), or PLA (Programmable Logic Array). The processor may also include a main processor and coprocessors. The main processor, also known as a CPU (Central Processing Unit), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, the processor may integrate a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content required to be displayed on the screen. In some embodiments, the processor may also include an AI (Artificial Intelligence) processor, which is used to handle computational operations related to machine learning.

[0058] The memory may include one or more computer-readable storage media, which may be non-transitory. The memory may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In some embodiments, the non-transitory computer-readable storage media in the memory are used to store at least one computer program, which is executed by a processor to implement the intelligent vehicle control method provided in the method embodiments of this application.

[0059] In some embodiments, the computer device may also optionally include: a peripheral device interface and at least one peripheral device. The processor, memory, and peripheral device interface can be connected via a bus or signal line. Each peripheral device can be connected to the peripheral device interface via a bus, signal line, or circuit board. Specifically, the peripheral device includes at least one of: radio frequency circuitry, a display screen, a camera assembly, audio circuitry, and a power supply.

[0060] Peripheral device interfaces can be used to connect at least one I / O (Input / Output) related peripheral device to the processor and memory. In some embodiments, the processor, memory, and peripheral device interface are integrated on the same chip or circuit board; in some other embodiments, any one or two of the processor, memory, and peripheral device interface can be implemented on separate chips or circuit boards, which is not limited in this embodiment.

[0061] Radio frequency (RF) circuits are used to receive and transmit RF signals, also known as electromagnetic signals. RF circuits communicate with communication networks and other communication devices via electromagnetic signals. RF circuits convert electrical signals into electromagnetic signals for transmission, or convert received electromagnetic signals back into electrical signals. In some embodiments, the RF circuit includes: an antenna system, an RF transceiver, one or more amplifiers, a tuner, an oscillator, a digital signal processor, a codec chipset, a user identity module card, etc. The RF circuit can communicate with other terminals through at least one wireless communication protocol. These wireless communication protocols include, but are not limited to: the World Wide Web, metropolitan area networks, intranets, various generations of mobile communication networks (2G, 3G, 4G, and 5G), wireless local area networks, and / or WiFi (Wireless Fidelity) networks. In some embodiments, the RF circuit may also include circuitry related to NFC (Near Field Communication), which is not limited in this application.

[0062] The present invention also discloses a computer-readable storage medium storing a computer program adapted for loading by a processor and executing a control method for a hydrostatic bulldozer hydraulic braking system disclosed in an embodiment of the present invention.

[0063] The present invention also discloses a computer program product, which includes a computer program. When the computer program is executed by a processor, it implements a control method for a hydrostatic bulldozer hydraulic braking system disclosed in the embodiments of the present invention.

[0064] The method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor. The software modules can reside in readily available storage media in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are omitted here.

[0065] Those skilled in the art will recognize that the units and algorithm steps described in conjunction with the embodiments herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0066] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A hydrostatic bulldozer hydraulic braking system, characterized in that, include: Hydraulic power source, main oil supply branch, backup oil supply branch, brake oil circuit, brake, brake pressure sensor, backup pressure sensor and controller; Both the main oil supply branch and the backup oil supply branch are connected to the hydraulic power source; both the main oil supply branch and the backup oil supply branch are also connected to the brake oil circuit; the brake oil circuit is connected to the brake. Brake pressure sensor is used to obtain the oil pressure in the brake fluid circuit; A backup pressure sensor is used to obtain the oil pressure in the backup oil supply branch; The controller is used to activate the backup oil supply branch when the oil pressure in the brake oil circuit is lower than the set oil pressure threshold value and remains so for a set time. Then, it determines the cause of the low oil pressure in the brake oil circuit based on the oil pressure in the brake oil circuit and the oil pressure in the backup oil supply branch.

2. The hydrostatic bulldozer hydraulic braking system as described in claim 1, characterized in that, The controller is used to determine that the low oil pressure in the brake circuit is caused by a blockage in the main oil supply branch when both the oil pressure in the brake circuit and the oil pressure in the backup oil supply branch are higher than the set oil pressure threshold; when the oil pressure in the brake circuit is lower than the set oil pressure threshold, but the oil pressure in the backup oil supply branch is higher than the set oil pressure threshold, the controller determines that the low oil pressure in the brake circuit is caused by a damaged brake pressure sensor; when both the oil pressure in the brake circuit and the oil pressure in the backup oil supply branch are lower than the set oil pressure threshold, the controller determines that the low oil pressure in the brake circuit is caused by low brake pressure.

3. The hydrostatic bulldozer hydraulic braking system as described in claim 2, characterized in that, The controller is also used to activate the active brake protection strategy when the reason for low oil pressure in the brake circuit is determined to be low brake pressure.

4. The hydrostatic bulldozer hydraulic braking system as described in claim 3, characterized in that, The controller is also used to control the vehicle's gear position not to exceed a set gear when the oil pressure in the backup fuel supply branch is lower than a set oil pressure threshold and higher than a first oil pressure threshold, and the duration exceeds a set time threshold, after the active braking protection strategy is activated; to control the engine speed to drop to idle speed when the oil pressure in the backup fuel supply branch is lower than the first oil pressure threshold and higher than a second oil pressure threshold, and the duration exceeds a set time threshold; and to control the bulldozer to brake and stop when the oil pressure in the backup fuel supply branch is lower than the second oil pressure threshold, and the duration exceeds a set time threshold.

5. The hydrostatic bulldozer hydraulic braking system as described in claim 1, characterized in that, Solenoid valves are installed in both the main fuel supply branch and the backup fuel supply branch. The controller controls the connection or disconnection of the main fuel supply branch and the backup fuel supply branch by controlling the opening and closing of the solenoid valves.

6. The hydrostatic bulldozer hydraulic braking system as described in claim 1, characterized in that, The controller and display device are connected in communication. The controller is used to generate alarm information based on the cause of low oil pressure in the brake fluid circuit; The display device is used to display alarm information.

7. The hydrostatic bulldozer hydraulic braking system as described in claim 1, characterized in that, The hydraulic power source includes a hydraulic pump and a hydraulic oil tank; one end of the hydraulic pump is connected to the hydraulic oil tank, and the other end of the hydraulic pump is connected to the oil supply pipe, which is connected to both the main oil supply branch and the backup oil supply branch.

8. The hydrostatic bulldozer hydraulic braking system as described in claim 7, characterized in that, An overflow valve is installed on the oil supply line.

9. A control method for a hydrostatic bulldozer hydraulic braking system as described in any one of claims 1-8, characterized in that, include: When the brake is supplied with oil only through the main oil supply branch, the oil pressure in the brake oil circuit is obtained; When the oil pressure in the brake oil circuit is lower than the set oil pressure threshold and remains so for a set time, the backup oil supply branch is activated. Obtain the oil pressure in the backup oil supply branch; Determine the cause of low brake fluid pressure based on the oil pressure in the brake fluid circuit and the oil pressure in the backup oil supply branch.

10. An electronic device, characterized in that, The device includes: A processor, adapted to execute computer programs; A computer-readable storage medium storing a computer program, which, when executed by the processor, implements the control method for a hydrostatic bulldozer hydraulic braking system as described in claim 9.

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