Mechanical backup self-checking method, controller and electronic hydraulic brake system

Abstract

The present invention proposes a mechanical backup self-check method, controller and electronic hydraulic brake system, which belongs to the field of vehicle braking. The method includes: controlling the CSV valve to close, and controlling the PSV valve and the SSV valve to open; when the brake pedal is detected to be displaced for the first time, controlling the electric cylinder to build pressure, and obtaining the first pressure building data of the brake pedal and the second pressure building data of the electric cylinder in real time; after determining that the blocking expectation is met according to the first pressure building data and the second pressure building data, when the brake pedal is detected to return to the zero position, controlling the CSV valve to open in sequence, and obtaining the third hydraulic value on the electric cylinder side in real time; if it is determined that the pressure relief expectation is met according to the change characteristics of the third hydraulic value, it is determined that the mechanical backup of the electronic hydraulic brake system is effective. In this way, the mechanical backup function is verified comprehensively and systematically, effectively ensuring that the mechanical backup function of the electronic hydraulic brake system operates well when it is switched to the working mode, and significantly improving the overall safety.

Description

Technical Field

[0001] The present invention relates to the field of vehicle braking, and in particular to a mechanical backup self-checking method, a controller and an electronic hydraulic braking system. Background Art

[0002] The integrated electronic hydraulic brake system is an advanced automotive braking technology that integrates the servo-electric booster with the master cylinder to achieve precise control of the brake pressure. The integrated electronic hydraulic brake system is particularly widely used in the automotive field, especially in hybrid and pure electric models. It can improve the vehicle's range and power performance by recycling the braking energy. In addition, in the field of public transportation and logistics, the integrated electronic hydraulic brake system can reduce the vehicle's braking interval and improve road traffic efficiency.

[0003] The integrated electronic hydraulic brake system generally includes a main brake circuit, an oil pot module, a mechanical brake circuit and a wheel end module. The main brake circuit and the mechanical brake circuit are connected to the oil pot module and the wheel end module respectively. The main brake circuit and the mechanical brake circuit can use the oil provided by the oil pot module to generate hydraulic pressure and transmit it to the wheel end module to control the vehicle braking. Among them, the wheel end module includes a first wheel group and a second wheel group, and the main brake circuit includes an electric cylinder and two PSV valves. The electric cylinder is connected to the first wheel group through the first PSV valve, and the electric cylinder is connected to the second wheel group through the second PSV valve. The mechanical brake circuit includes a brake pedal, a master cylinder and two CSV valves. The brake pedal is connected to the master cylinder. The master cylinder is connected between the first PSV valve and the first wheel group through the first CSV valve. The master cylinder is connected between the second PSV valve and the second wheel group through the second CSV valve, and the master cylinder is also connected to the oil pot through the SSV valve.

[0004] The main brake circuit realizes the mechanical backup function of the integrated electronic hydraulic brake system. Its main purpose is to ensure that the vehicle still has basic braking ability when the electronic control part fails. When the mechanical backup function fails or fails, the braking distance of the vehicle will increase significantly, resulting in a decrease in braking performance, which may lead to safety hazards such as the vehicle being unable to stop in time and causing accidents.

[0005] Therefore, there is an urgent need for a mechanical backup self-check solution for the integrated electronic hydraulic brake system to check whether the mechanical backup function can work normally before the vehicle is powered on and enters the driving state, so as to timely detect failures and improve safety. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a mechanical backup self-check method, a controller and an electronic hydraulic brake system, so as to automatically check whether the mechanical backup function fails before the integrated electronic hydraulic brake system is powered on and enters the working mode, thereby ensuring safety.

[0007] In order to achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows:

[0008] In a first aspect, the present invention provides a mechanical backup self-check method, which is applied to a controller of an electronic hydraulic brake system, wherein the controller is respectively connected to an electric cylinder, a PSV valve, a CSV valve, and an SSV valve of the electronic hydraulic brake system, and the method comprises:

[0009] Controlling the CSV valve to close, and controlling the PSV valve and the SSV valve to open;

[0010] When the first displacement of the brake pedal is detected, the electric cylinder is controlled to build pressure, and first pressure building data of the brake pedal and second pressure building data of the electric cylinder are acquired in real time;

[0011] judging whether the blocking expectation is achieved according to the first pressure building data and the second pressure building data;

[0012] If yes, then when it is detected that the brake pedal returns to zero position, the CSV valves are controlled to open sequentially, and the third hydraulic pressure value on the electric cylinder side is acquired in real time;

[0013] judging whether the pressure relief expectation is reached according to the change characteristics of the third hydraulic pressure value;

[0014] If the pressure relief expectation is reached, it is determined that the mechanical backup of the electronic hydraulic brake system is effective.

[0015] Optionally, the first pressure-building data includes a pedal displacement value of the brake pedal and a first hydraulic pressure value of the master cylinder, and the second pressure-building data includes a piston displacement value and a second hydraulic pressure value of the electric cylinder;

[0016] The step of judging whether the blocking expectation is achieved according to the first pressure building data and the second pressure building data comprises:

[0017] Fitting the change relationship between the pedal displacement value and the first hydraulic pressure value to obtain a first curve;

[0018] Fitting the variation relationship between the piston displacement value and the second hydraulic pressure value to obtain a second curve;

[0019] Determining whether the first curve and the second curve both conform to their corresponding expected curves;

[0020] If yes, it is determined that the blocking expectation is achieved.

[0021] Optionally, a first pressure sensor is provided between the electric cylinder and one of the PSVs, and an input end of the controller is connected to an output end of the first pressure sensor;

[0022] The step of controlling the CSV valves to open sequentially and acquiring the third hydraulic pressure value of the electric cylinder side in real time includes:

[0023] controlling the first CSV valve to open, and sampling the first pressure sensor to obtain a third hydraulic pressure value;

[0024] When the third hydraulic value is less than the target pressure, the second CSV valve is controlled to open, and the first pressure sensor is continuously sampled to obtain the third hydraulic value; wherein the target pressure is the target value of the electric cylinder pressure build-up.

[0025] Optionally, the step of judging whether the pressure relief expectation is reached according to the change characteristics of the third hydraulic pressure value includes:

[0026] The time when the second CSV valve is opened is used as the segmentation time;

[0027] constructing a first hydraulic pressure curve according to the third hydraulic pressure value obtained before the segmentation time, and obtaining a first slope of the first hydraulic pressure curve;

[0028] constructing a second hydraulic pressure curve according to the third hydraulic pressure value obtained after the segmentation time, and obtaining a second slope of the second hydraulic pressure curve;

[0029] determining whether the first slope is less than the second slope;

[0030] If so, it is determined that the pressure relief expectation has been achieved;

[0031] If not, it is determined that the pressure relief expectation has not been achieved.

[0032] Optionally, after the step of determining whether the mechanical backup of the electronic hydraulic brake system is effective, the method further comprises:

[0033] A return-to-zero instruction is sent to the electric cylinder to instruct the electric cylinder to control the piston to move to the zero position, and when it is detected that the piston returns to the zero position, the CSV valve is controlled to close.

[0034] Optionally, after the step of determining whether the blocking expectation is achieved, the method further includes:

[0035] If the blocking expectation is not achieved, a fault alarm message is generated, and the CSV valve is controlled to be turned on and the PSV valve is controlled to be closed to maintain the mechanical backup braking state.

[0036] Optionally, after the step of judging whether the pressure relief expectation is reached according to the change characteristics of the third hydraulic pressure value, the method further comprises:

[0037] If the pressure relief expectation is not achieved, a fault alarm message is generated, and the PSV valve is controlled to close to prohibit entering the driving state.

[0038] Optionally, the step of controlling the electric cylinder to build up pressure includes:

[0039] The electric cylinder is controlled to build pressure according to the target pressure, wherein the target pressure is greater than the hydraulic pressure built up when the brake pedal is displaced.

[0040] In a second aspect, the present invention provides a controller, comprising a processor and a memory, wherein the memory stores a computer program executable by the processor, and the processor can execute the computer program to implement the mechanical backup self-check method as described in the first aspect.

[0041] In a third aspect, the present invention provides an electronic hydraulic braking system, comprising a controller as described in the second aspect, as well as a main braking circuit, an oil tank module, a mechanical braking circuit and a wheel end module, wherein the main braking circuit and the mechanical braking circuit are respectively connected to the oil tank module and the wheel end module.

[0042] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the mechanical backup self-check method as described in the first aspect.

[0043] The mechanical backup self-check method, controller and electronic hydraulic brake system provided by the embodiment of the present invention include: controlling the CSV valve to close, and controlling the PSV valve and the SSV valve to open; when the brake pedal is detected to be displaced for the first time, controlling the electric cylinder to build pressure, and obtaining the first pressure building data of the brake pedal and the second pressure building data of the electric cylinder in real time; after determining that the blocking expectation is met according to the first pressure building data and the second pressure building data, when the brake pedal is detected to return to zero position, controlling the CSV valve to open in sequence, and obtaining the third hydraulic value on the electric cylinder side in real time; according to the change characteristics of the third hydraulic value, determining that the pressure relief expectation is met, if so, determining that the mechanical backup of the electronic hydraulic brake system is effective. In this way, first detect whether the blocking of the mechanical brake circuit is normal, and then check whether the pressure relief of the mechanical brake circuit is normal after detecting that the blocking is normal, so as to comprehensively and systematically verify the effectiveness and reliability of the mechanical backup function. Therefore, through precise effectiveness detection, it is effectively ensured that the mechanical backup function of the electronic hydraulic brake system operates well when it is switched to the working mode, which significantly improves the overall safety.

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0046] Figure 1 A schematic structural diagram of an electronic hydraulic brake system provided by an embodiment of the present invention is shown.

[0047] Figure 2 A schematic structural diagram of an electronic device provided by an embodiment of the present invention is shown.

[0048] Figure 3 One of the flow charts of the mechanical backup self-check method provided by the embodiment of the present invention is shown.

[0049] Figure 4 Shows Figure 3 Schematic diagram of the process flow of some sub-steps of step 13.

[0050] Figure 5 Shows Figure 3 Schematic diagram of the process flow of some sub-steps of step 14.

[0051] Figure 6 Shows Figure 3 Schematic diagram of the process flow of some sub-steps of step 15.

[0052] Figure 7 The second flowchart of the mechanical backup self-checking method provided by the embodiment of the present invention is shown.

[0053] Figure 8 A block diagram of a mechanical backup self-checking device provided by an embodiment of the present invention is shown.

[0054] Explanation of the reference numerals: 10 - electronic hydraulic braking system; 110 - controller; 120 - main braking circuit; 1201 - electric cylinder; 130 - oil tank module; 140 - mechanical braking circuit; 1401 - brake pedal; 1402 - master cylinder; 150 - wheel end module; 1501 - wheel; 1502 - boost valve; 1503 - pressure reducing valve; 160 - first pressure sensor; 170 - second pressure sensor; 180 - stroke sensor; 190 - simulation chamber; 20 - electronic device; 210 - memory; 220 - processor; 230 - communication module; 30 - mechanical backup self-test device; 310 - circuit control module; 320 - pressure building sampling module; 330 - first discrimination module; 340 - pressure relief control module; 350 - second discrimination module; 360 - result acquisition module. DETAILED DESCRIPTION

[0055] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0056] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0057] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0058] The mechanical backup self-checking method provided by the embodiment of the present invention can be applied to Figure 1 In the electronic hydraulic brake system 10 shown, the electronic hydraulic brake system 10 includes a controller 110, a main brake circuit 120, an oil tank module 130, a mechanical brake circuit 140 and a wheel end module 150. The main brake circuit 120 and the mechanical brake circuit 140 are respectively connected to the oil tank module 130 and the wheel end module 150. The main brake circuit 120 and the mechanical brake circuit 140 can use the oil provided by the oil tank module 130 to generate hydraulic pressure and transmit it to the wheel end module 150 to control vehicle braking.

[0059] Among them, the wheel-end module 150 includes a first wheel group and a second wheel group, the main brake circuit 120 includes an electric cylinder 1201 and two PSV valves, the pressure building chamber of the electric cylinder 1201 is connected to three oil circuits, one of which is connected to the oil pot module 130, the pressure building chamber of the electric cylinder 1201 is connected to the first wheel group through the second oil circuit and the first PSV valve on the oil circuit, and the pressure building chamber of the electric cylinder 1201 is connected to the second wheel group through the third oil circuit and the second PSV valve on the oil circuit.

[0060] The mechanical brake circuit 140 includes a brake pedal 1401, a master cylinder 1402 and two CSV valves. The pressure-building brake pedal 1401 is connected to the master cylinder 1402. The master cylinder 1402 includes a first brake cylinder and a second brake cylinder. The first brake cylinder is connected to three oil circuits, wherein the first oil circuit is connected to the oil pot module 130. The first brake cylinder is connected to the first PSV valve and the first wheel group through the second oil circuit and the first CSV valve on the oil circuit. The first brake cylinder is connected to the oil pot module 130 through the third oil circuit and the SSV valve on the oil circuit. The second brake cylinder is connected to two oil circuits, wherein the first oil circuit is connected to the oil pot module 130. The second brake cylinder is connected to the second PSV valve and the second wheel group through the second oil circuit and the second CSV valve on the oil circuit.

[0061] In addition, the electronic hydraulic brake system 10 can also include a stroke sensor 180, a first pressure sensor 160 and a second pressure sensor 170. The stroke sensor 180 is arranged on the brake pedal 1401, the first pressure sensor 160 is arranged on the oil circuit between the pressure building chamber and the second PSV valve, and the second pressure sensor 170 is arranged on the oil circuit between the second brake cylinder and the second CSV valve.

[0062] In this embodiment, various solenoid valves such as CSV valves, PSV valves, and SSV valves are isolation valves on the oil circuit. The controller 110 can communicate with the motor of the electric cylinder 1201, the CSV valve, the PSV valve, the SSV valve, the stroke sensor 180, the first pressure sensor 160, the second pressure sensor 170, and the isolation valves of other modules and devices that need to be electrically controlled through the bus to control the working state of the motor and the conduction and disconnection of each isolation valve.

[0063] In the energized state, the PSV valve (i.e. Figure 1 PSV1 and PSV2 in the power supply are connected to the SSV, that is, they are in the open state, and the CSV valve is disconnected, that is, they are in the closed state. Conversely, in the power-off state, the PSV valve (that is, Figure 1 The PSV1 and PSV2 in the valve are disconnected from the SSV valve and are in a closed state, while the CSV valve is connected and is in an open state.

[0064] Since the pressure building chamber is connected to the oil tank module 130 through the oil circuit, when the main brake circuit 120 responds to the braking request, the two PSV valves are in the on state, and in the process of the piston moving to the bottom of the pressure building chamber, the pressure building chamber generates hydraulic pressure by extracting oil from the oil tank module 130. Then, the pressure building chamber transmits the generated hydraulic pressure to the first wheel group and the second wheel group through the two PSV valves respectively, so as to realize the braking demand of the vehicle where the voltage midnight brake system is located.

[0065] When the vehicle in which the midnight voltage brake system is located generates a mechanical braking demand, the two CSV valves are de-energized and in an on state, and the pressure-building chamber and the first wheel group and the second wheel group are in a closed state. When the brake pedal 1401 is pressed, the master cylinder 1402 draws oil from the oil tank module 130 to generate hydraulic pressure, and then transmits the hydraulic pressure to the first wheel group and the second wheel group through the two CSV valves to achieve vehicle braking.

[0066] The first wheel group and the second wheel group each include two wheels 1501, and each wheel 1501 is equipped with a boost valve 1502 and a pressure reducing valve 1503. For example, the wheel 1501 numbered 1F is equipped with a boost valve 1502 numbered IV1F and a pressure reducing valve 1503 numbered OV1F, the wheel 1501 numbered 2F is equipped with a boost valve 1502 numbered IV2F and a pressure reducing valve 1503 numbered OV2F, the wheel 1501 numbered 1R is equipped with a boost valve 1502 numbered IV1R and a pressure reducing valve 1503 numbered OV1R, and the wheel 1501 numbered 2R is equipped with a boost valve 1502 numbered IV2R and a pressure reducing valve 1503 numbered OV2R.

[0067] The main function of the boost valve 1502 is to increase the pressure in the wheel cylinder of the wheel 1501. When the driver needs more braking force, the controller 110 will send a signal to the boost valve 1502 to open it, allowing high-pressure brake fluid (i.e., oil) to flow into the wheel cylinder of the wheel 1501, thereby increasing the braking force. The function of the pressure reducing valve 1503 is to reduce the pressure in the wheel cylinder of the brake wheel 1501. When the ABS (anti-lock braking system) is working, if it is detected that the wheel 1501 is about to lock, the pressure reducing valve will open, allowing the high-pressure brake fluid in the wheel cylinder of the wheel 1501 to flow back to the oil tank module 130, thereby reducing the braking force, preventing the wheel 1501 from locking, and maintaining the vehicle's controllability and stability.

[0068] The electronic hydraulic brake system 10 also includes a simulation chamber 190, an SSV valve (which may be a solenoid valve) and a TSV valve. The simulation chamber 190 is arranged between the SSV valve and the oil pot module 130. When the mechanical brake circuit 140 is working, the SSV valve is closed, and when the main brake circuit 120 is working, the SSV valve is turned on. The TSV valve is arranged between the oil pot module 130 and the master cylinder 1402, and is mainly responsible for controlling the on-off between the oil pot module 130 and the master cylinder 1402. Here, the controller 110 is also used to implement the mechanical backup self-test method provided in an embodiment of the present invention. It should be noted that the controller 110 may be a driving computer, a vehicle-mounted terminal, etc. of the vehicle in which the electronic hydraulic brake system 10 is located, or it may be the control device of the electronic hydraulic brake system 10 itself.

[0069] Please refer to Figure 2, is a block diagram of an electronic device 20, which may be Figure 1 The controller 110 in the electronic hydraulic brake system 10 shown. The electronic device 20 includes a memory 210, a processor 220 and a communication module 230. The memory 210, the processor 220 and the communication module 230 are electrically connected to each other directly or indirectly to achieve data transmission or interaction. For example, these components can be electrically connected to each other through one or more communication buses or signal lines.

[0070] The memory 210 is used to store programs or data, and can be, but not limited to, a random access memory 210, a read-only memory 210, a programmable read-only memory 210, an erasable read-only memory 210, an electrically erasable read-only memory 210, and the like.

[0071] The processor 220 is used to read / write data or programs stored in the memory 210 and execute corresponding functions. For example, Figure 1 In the electronic hydraulic brake system 10 shown, the processor 220 in the controller 110 executes the computer program stored in the memory 210 to implement the mechanical backup self-check method provided in the embodiment of the present invention.

[0072] The communication module 230 is used to establish a communication connection between the electronic device 20 and other communication terminals, sensors and solenoid valves through wireless communication such as the Internet, WiFi, Bluetooth, or communication data lines such as buses, and is used to send and receive data. Figure 1 In the electronic hydraulic brake system 10 shown, the controller 110 can receive detection data from various sensors through the communication module 230, and send control signals to the CSV valve, PSV valve, SSV valve, etc.

[0073] It should be understood that Figure 2 The structure shown is only a schematic diagram of the structure of the electronic device 20. The electronic device 20 may also include Figure 2 More or fewer components as shown, or with Figure 2 Different configurations are shown. Figure 2 Each component shown in the figure can be implemented by hardware, software or a combination thereof.

[0074] Please refer to Figure 3 The mechanical backup self-check method provided by the embodiment of the present invention includes steps 11 to 16. Figure 1 In the electronic hydraulic brake system 10 shown, the controller 110 can Figure 2 The structure shown in , through the processor 220 executing the stored computer program, performs the above steps 11 to 16 to implement the mechanical backup self-check method.

[0075] Step 11, control the CSV valve to close, and control the PSV valve and the SSV valve to open.

[0076] Step 12, when the first displacement of the brake pedal is detected, the electric cylinder is controlled to build pressure, and the first pressure building data of the brake pedal and the second pressure building data of the electric cylinder are obtained in real time.

[0077] Step 13: determine whether the blocking expectation is achieved based on the first pressure building data and the second pressure building data. If so, proceed to step 14.

[0078] Step 14, when it is detected that the brake pedal returns to zero position, the CSV valves are controlled to open in sequence, and the third hydraulic pressure value on the electric cylinder side is obtained in real time.

[0079] Step 15: determine whether the pressure relief expectation is reached according to the change characteristics of the third hydraulic pressure value. If yes, proceed to step 16.

[0080] Step 16, determining whether the mechanical backup of the electronic hydraulic brake system is effective.

[0081] Among them, the blocking expectation characterizes the pressure building characteristics of the brake pedal and the pressure building characteristics of the electric cylinder when the blocking function of the CSV valve is fault-free, the opening functions of the PSV valve and the SSV valve are fault-free, the displacement pressure building function of the brake pedal is fault-free, and the pressure building function of the electric cylinder is fault-free.

[0082] The pressure relief expectation characterizes the change characteristics of the hydraulic pressure value on the electric cylinder side when the PSV valve and SSV valve open without fault, and the CSV valve opens without fault to relieve pressure.

[0083] For example, in combination Figure 1 In the electronic hydraulic brake system 10 shown, when the electronic hydraulic brake system 10 is powered on and triggered to enter the mechanical backup self-test, the controller 110 outputs high level control signals to the CSV valve, PSV valve and SSV valve respectively to control the CSV valve to close and the PSV valve and SSV valve to open. At this time, the ideal state is that the oil circuits between the electric cylinder 1201 and the first wheel group and the second wheel group are both in a flow state, and the oil circuits between the master cylinder 1402 and the first wheel group and the second wheel group are both in a blocked state.

[0084] In this state, the controller 110 can receive the displacement sampling value transmitted by the stroke sensor 180 on the brake pedal 1401 in real time. When the first displacement sampling value is not 0 (i.e., the brake pedal 1401 is displaced for the first time), the controller 110 controls the electric cylinder 1201 to build pressure, and obtains the first pressure building data of the brake pedal 1401 and the second pressure building data of the electric cylinder 1201 in real time. Thus, the controller 110 determines whether the blocking expectation is currently achieved based on the first pressure building data and the second pressure building data. If so, it means that the blocking function of the CSV valve on the mechanical brake circuit 140 is normal, and the pressure building function of the master cylinder 1402 is also normal. In this case, when the displacement sampling value transmitted by the stroke sensor 180 returns to 0 (i.e., the brake pedal 1401 returns to zero), the controller 110 outputs low-level control signals to the two CSV valves in turn to control the CSV valves to open in turn, and obtains the third hydraulic value on the electric cylinder 1201 side in real time through the first pressure sensor 160.

[0085] It should be noted that when the CSV valve is in the open state, if the brake pedal 1401 is released and returns to the zero position, the oil in the mechanical brake circuit 140 will return to the oil pot module 130 through the oil circuit connected to the oil pot module 130 to relieve pressure. At the same time, since the PSV valve is also in the open state, the oil in the main brake circuit 120 will also return to the oil circuit through the oil circuit between the pressure building chamber and the oil pot module 130 to relieve pressure.

[0086] Therefore, the controller 110 can determine whether the expected pressure relief is achieved based on the changing characteristics of the third hydraulic value. If so, it means that the conduction function of the CSV valve on the mechanical brake circuit 140 is normal and the pressure relief of the mechanical brake circuit 140 is normal, and thus it can be determined that the mechanical backup of the electronic hydraulic brake system 10 is effective.

[0087] The above mechanical backup self-check method first detects whether the mechanical brake circuit is blocked normally through steps 11 to 16. After the blocking is detected to be normal, the pressure relief of the mechanical brake circuit is checked to verify the effectiveness and reliability of the mechanical backup function in a comprehensive and systematic manner. Thus, through precise effectiveness detection, it is effectively ensured that the mechanical backup function of the electronic hydraulic brake system operates well when it is switched to the working mode, which significantly improves the overall safety.

[0088] Among them, the method of controlling the electric cylinder to build pressure in step 12 can be flexibly selected. For example, the electric cylinder can establish the same hydraulic pressure in multiple mechanical backup self-tests, or the electric cylinder can establish different hydraulic pressures in multiple mechanical backup self-tests. The implementation method can be flexibly set.

[0089] In order to assist in detecting the blocking of the SCV valve in the mechanical brake circuit, the pressure building function of the master cylinder, the oil flow function of the PSV valve in the main brake circuit, and the pressure building capacity of the electric cylinder, and to assist in detecting the pressure relief function of the subsequent mechanical brake circuit, when controlling the pressure building of the electric cylinder in step 12, the pressure building of the electric cylinder can be controlled according to the target pressure.

[0090] The target pressure is a preset value obtained by fitting based on a large amount of historical data or calibration test data, or it can be a value set by technicians based on experience. The target pressure is always greater than the hydraulic pressure established when the brake pedal is displaced. Since the PSV valve is in an open state, the hydraulic pressure established during the pressure building process of the electric cylinder will provide braking force to the wheel-end module. Finally, the braking force of the wheel-end module and the hydraulic pressure at the location where the first pressure sensor is set are maintained at the target pressure.

[0091] For example, if the target pressure is 40 bar, then the final braking force of the wheel-end module and the hydraulic pressure at the location where the first pressure sensor is set are both 40 bar.

[0092] In this way, the wheel-end module 150 obtains the target pressure as the braking force by building up pressure through the electric cylinder 1201, and the braking force is greater than the braking force provided by the pressure built up by the master cylinder 1402 when the brake pedal 1401 is stepped on. Therefore, when the CSV valve opens to release pressure, the pressure of the wheel-end module 150 is greater than the pressure provided by the mechanical brake circuit 140. The hydraulic pressure of the mechanical brake circuit 140 does not need to reach the wheel-end module 150 first, and can be quickly and immediately released, thereby shortening the pressure release time, and then shortening the pressure release detection time, thereby improving the speed and efficiency of the mechanical backup self-inspection.

[0093] In addition, the data contents of the first pressure building data and the second pressure building data obtained in step 12 can be flexibly set, for example, they can only include hydraulic pressure values, or they can include hydraulic pressure values ​​and other data. The above data content setting is only an example, and in actual applications, it can be adaptively adjusted according to the detection target.

[0094] In order to detect the blocking function of the CSV valve and the pressure-building function of the electric cylinder and the pressure-building function of the master cylinder in steps 11 to 13, the first pressure-building data may include the pedal displacement value of the brake pedal and the first hydraulic value of the master cylinder, and the second pressure-building data may include the piston displacement value and the second hydraulic value of the electric cylinder. On this basis, the implementation method of step 13 can be flexibly selected. For example, it can be to judge whether each data item reaches its corresponding expected value separately, or it can be to use a pre-trained neural network model to process the first pressure-building data and the second pressure-building data to generate a judgment result. In this embodiment, there is no limitation on the implementation method of step 13.

[0095] In order to more accurately detect the blocking function of the CSV valve in the mechanical brake circuit, the pressure-building function of the master cylinder, and the pressure-building function of the electric cylinder in the main brake circuit when the CSV valve is closed and the PSV valve and SSV valve are opened, the concept of judging based on the relationship between the displacement and the hydraulic value is introduced in step 13. For example, referring to Figure 4 , step 13 may include steps 131 to 135.

[0096] Step 131 , fitting the changing relationship between the pedal displacement value and the first hydraulic pressure value to obtain a first curve.

[0097] Here, combined Figure 1 In the electronic hydraulic brake system 10 shown, the first hydraulic pressure value is collected by the second pressure sensor 170, and there are multiple first hydraulic pressure values, which cover the master cylinder hydraulic pressure values ​​corresponding to each specific time point from the start of the movement of the brake pedal 1401 to the stage of stable displacement. Similarly, there are multiple pedal displacement values, which are collected by the travel sensor 180 set on the brake pedal 1401, and the multiple pedal displacement values ​​cover the brake pedal displacement corresponding to each specific time point from the start of the movement of the brake pedal 1401 to the stage of stable displacement.

[0098] Therefore, any method that can fit the data relationship, such as linear regression, polynomial regression, decision tree, random forest, neural network, etc., can be used to fit the relationship between the pedal displacement value as the independent variable and the first hydraulic value as the dependent variable to obtain the first curve. Conversely, the first hydraulic value can also be used as the independent variable and the pedal displacement value as the dependent variable to fit the relationship between the two to obtain the first curve (i.e., the relationship formula).

[0099] Step 132: Fit the variation relationship between the piston displacement value and the second hydraulic pressure value to obtain a second curve.

[0100] Similar to the above 132, there are multiple second hydraulic pressure values, which are collected by the first pressure sensor 160. The multiple second hydraulic pressure values ​​cover the hydraulic pressure values ​​corresponding to each specific time point from the stage when the electric cylinder 1201 starts to build pressure until the target pressure is reached. Similarly, there are multiple piston displacement values, which are collected by the stroke sensor 180 set on the piston or the photoelectric sensor, encoder, etc. connected to the motor. The multiple piston displacement values ​​correspond to the brake pedal displacement at each specific time point from the stage when the electric cylinder 1201 starts to build pressure until the target pressure is reached.

[0101] Therefore, any method that can fit the data relationship, such as linear regression, polynomial regression, decision tree, random forest, neural network, etc., can be used to fit the relationship between the piston displacement value as the independent variable and the second hydraulic pressure value as the dependent variable to obtain the second curve. Conversely, the second hydraulic pressure value can also be used as the independent variable and the piston displacement value as the dependent variable to fit the relationship between the two to obtain the second curve (i.e., the relationship formula).

[0102] Step 133, determine whether the first curve and the second curve are both consistent with their corresponding expected curves. If yes, execute step 134, if no, execute step 135.

[0103] Step 134, determining whether the blocking expectation has been achieved.

[0104] Step 135, determining that the blocking expectation is not achieved.

[0105] It should be understood that the expected curve is pre-set, and only when the first curve and the second curve both conform to their corresponding expected curves, does it mean that the sealing function of the CSV valve is normal, the pressure building function of the master cylinder 1402 is normal, and the pressure building function of the electric cylinder 1201 is normal, that is, the pressure building and sealing functions of the mechanical backup are normal. Otherwise, at least one of the sealing function of the CSV valve, the pressure building function of the master cylinder 1402, and the pressure building function of the electric cylinder 1201 is faulty.

[0106] Through the above steps 131 to 132 , the effectiveness of the CSV valve blocking function of the mechanical backup, the main cylinder pressure building function and the electric cylinder pressure building function can be determined more accurately and reliably.

[0107] After it is determined through the above steps 131 to 132 that the blocking expectation is achieved, the controller obtains in real time the displacement sampling value of the travel sensor arranged on the brake pedal (i.e., the pedal displacement value). When the displacement sampling value indicates that the brake pedal returns to the zero position, step 14 is executed, i.e., the CSV valves are controlled to open in sequence, and the sampling value of the first pressure sensor (the sensor is arranged in the oil circuit between the second PSV valve) at this time is used as the third hydraulic value.

[0108] The CSV valve is opened, that is, the CSV valve is powered off (or outputs a low level, etc.) to make the CSV valve conductive. Also, the method of controlling the CSV valves to open in sequence can be flexibly set, for example, it can be opened at a preset time interval, or the opening time of each CSV valve can be determined according to the change of a certain data detected, and the specific implementation method is not limited.

[0109] It should be noted that since the brake pedal 1401 has returned to zero position, when the CSV valve is opened, if the conduction function of the CSV valve is normal, the oil in the corresponding oil circuit (including the oil in the main brake circuit 120 and the oil in the mechanical brake circuit 140) will flow back to the oil pot module 130 through the oil circuit between the master cylinder 1402 and the oil pot module 130, and the oil circuit between the wheel end module 150 and the oil pot module 130, thereby completing the pressure relief.

[0110] In order to quickly detect the conduction / opening function of each CSV valve, the idea of ​​opening the CSV valves in sequence according to the change of the third hydraulic value is introduced in step 14, referring to Figure 5 , step 14 may include steps 141 to 143.

[0111] Step 141, control the first CSV valve to open, and sample the first pressure sensor to obtain a third hydraulic pressure value.

[0112] Here, before the first CSV valve is opened, the hydraulic pressure of the oil circuit where the first pressure sensor is located is equal to the target pressure, which is the target pressure value of the electric cylinder in step 12.

[0113] Step 143: when the third hydraulic pressure value is less than the target pressure, the second CSV valve is controlled to open, and the first pressure sensor is continuously sampled to obtain the third hydraulic pressure value.

[0114] The target pressure is the target value of the electric cylinder pressure build-up.

[0115] It should be noted that, when the pressure relief function (i.e., conduction function) of the first CSV valve is normal, after the first CSV valve is controlled to open, the oil in the oil circuit corresponding to the CSV valve (including the oil circuit between the connected brake cylinder and the oil pot module, and the oil circuit between the pressure building chamber and the oil pot module) begins to flow back to the oil pot module, i.e., pressure relief begins. However, since the hydraulic pressure value previously established in the pressure building chamber is the target pressure, which is greater than the hydraulic pressure established by the brake cylinder at the CSV valve (i.e., the hydraulic pressure established by the master cylinder), after a period of pressure relief that may be long or short, the third hydraulic pressure value must begin to be less than the target pressure. At this point, it means that the pressure relief function of the first CSV valve is normal.

[0116] On the contrary, if the pressure relief function (i.e., conduction function) of the first CSV valve fails, the pressure cannot be relieved after the first CSV valve is controlled to open.

[0117] Therefore, in step 143, when the third hydraulic value is less than the target pressure, it means that the pressure relief of the first CSV valve is preliminarily confirmed to be normal, and the second CSV valve is controlled to open, and the first pressure sensor is continuously sampled to obtain subsequent changes in the third hydraulic value.

[0118] Therefore, in step 15, it is possible to determine whether the conduction of each CSV valve is effective and whether the pressure relief function of the mechanical backup is effective according to the change characteristics of the third hydraulic pressure value.

[0119] The change characteristic of the third hydraulic pressure value may be a change speed or a change difference, and the measurement method thereof is not limited.

[0120] In order to accurately determine the effectiveness of conduction and pressure relief of each CSV valve, the idea of ​​calculating the variation characteristics of the third hydraulic pressure value in sections according to the opening time of the second CSV valve is introduced in step 15. Figure 6 , step 15 may include steps 151 to 156.

[0121] Step 151, taking the moment when the second CSV valve opens as the segmentation moment.

[0122] Here, when the first CSV valve is opened, the first pressure sensor starts to collect the third hydraulic pressure value at a specific time period, and when the segmentation time is reached, the third hydraulic pressure value is slightly smaller than the target pressure for the first time.

[0123] Step 152: construct a first hydraulic pressure curve according to the third hydraulic pressure value obtained before the segmentation time, and obtain a first slope of the first hydraulic pressure curve.

[0124] Step 153: construct a second hydraulic pressure curve according to the third hydraulic pressure value obtained after the segmentation time, and obtain a second slope of the second hydraulic pressure curve.

[0125] Step 154, determining whether the first slope is smaller than the second slope.

[0126] If yes, execute step 155 , if no, execute step 156 .

[0127] Step 155, determining that the pressure relief expectation has been reached.

[0128] Step 156, determining that the pressure relief expectation has not been achieved.

[0129] Here, the first hydraulic pressure curve and the second hydraulic pressure curve can be fitted by taking the third hydraulic pressure value as the dependent variable and the time when the third hydraulic pressure value is collected as the independent variable, using any method that can fit the data relationship, such as linear regression, polynomial regression, decision tree, random forest, neural network, etc. Conversely, the third hydraulic pressure value can be taken as the independent variable and the time when the third hydraulic pressure value is collected as the dependent variable, and the fitting can be obtained.

[0130] When the first slope is less than the second efficiency, it means that the pressure relief speed after the segmentation moment is faster than before the segmentation moment, which means that the pressure relief function of the second CSV valve is effective and the pressure relief expectation is achieved at this time. Otherwise, the pressure relief function of the second CSV valve fails.

[0131] Through the above steps 151 to 156 , it is possible to more accurately determine whether the conduction and pressure relief function of each CSV valve is effective.

[0132] After executing the above steps 151 to 156, if the expected pressure relief is achieved, it means that the pressure building function of the master cylinder 1402, the blocking function of the CSV valve, and the conduction and pressure relief function of the CSV valve are all effective. At this time, step 16 can determine that the mechanical backup of the electronic hydraulic brake system 10 is effective.

[0133] When it is determined that the mechanical backup of the electronic hydraulic brake system 10 is effective, in order to quickly reset it to ensure that it is not affected after entering the working mode, and at the same time improve the self-checking speed and efficiency. Figure 7 The mechanical backup self-check method provided in the embodiment of the present invention further includes step 17, in which the electronic hydraulic brake system 10 is reset to ensure that it is not affected after entering the working mode.

[0134] Step 17, sending a return to zero command to the electric cylinder to instruct the electric cylinder to control the piston to move to the zero position, and when it is detected that the piston returns to the zero position, controlling the CSV valve to close.

[0135] Through the above step 17, the electric cylinder piston is first returned to zero, and then the CSV valve is closed, so that the oil circuit space where the electric cylinder is located during the return to zero process is not closed, so as to reduce the resistance when the piston moves, increase the return to zero speed, and thus shorten the self-test time and improve efficiency.

[0136] In order to avoid the occurrence of safety accidents when the vehicle with the electronic hydraulic brake system enters the driving state in the case of failure of the mechanical backup function, the safety is improved. When a fault is introduced in the mechanical backup self-check method provided in the embodiment of the present invention, the fault is reported and the vehicle is prohibited from driving. Please continue to refer to Figure 7 , may further include step 18 and step 19, when it is determined in step 13 that the blocking expectation is not achieved, step 18 is executed, and when it is determined in step 15 that the pressure relief expectation is not achieved, step 19 is executed.

[0137] Step 18, generating fault alarm information, and controlling the CSV valve to be turned on, and the PSV valve to be turned off, so as to maintain the mechanical backup braking state.

[0138] When it is determined that the blocking expectation is not achieved, the main brake circuit 120 is disconnected by closing the PSV valve to prohibit the main brake circuit 120 from providing braking force, and only the mechanical brake circuit 140 is allowed to provide braking force.

[0139] Step 19, generating fault alarm information and controlling the PSV valve to close to prohibit entering the driving state.

[0140] Similar to the above step 18, since the CSV valve has been opened in step 14, when it is determined that the pressure relief function has failed, the main brake circuit 120 is disconnected by closing the PSV valve to prohibit the main brake circuit 120 from providing braking force, and only allow the mechanical brake circuit 140 to provide braking force.

[0141] Through the above steps 18 and 19, when the failure of the mechanical backup is detected, the main brake circuit is prohibited from providing braking force to prohibit the vehicle from traveling, thereby greatly improving safety.

[0142] Based on the same concept as the above mechanical backup self-check method, refer to Figure 8 The embodiment of the present invention also provides a mechanical backup self-checking device 30, which can be applied to Figure 1 The controller 110 in the electronic hydraulic brake system 10 shown includes a circuit control module 310 , a pressure building sampling module 320 , a first determination module 330 , a pressure relief control module 340 , a second determination module 350 and a result acquisition module 360 ​​.

[0143] The loop control module 310 is used to control the CSV valve to close, and control the PSV valve and the SSV valve to open.

[0144] The pressure building sampling module 320 is used to control the electric cylinder to build pressure when the first displacement of the brake pedal is detected, and to obtain the first pressure building data of the brake pedal and the second pressure building data of the electric cylinder in real time.

[0145] The first pressure building module is used to determine whether the blocking expectation is achieved according to the first pressure building data and the second pressure building data.

[0146] The pressure relief control module 340 is used to control the CSV valves to open in sequence and obtain the third hydraulic value on the electric cylinder side in real time if it is determined that the blocking expectation is achieved and the brake pedal 1401 is detected to return to the zero position.

[0147] The second determination module 350 is used to determine whether the pressure relief expectation is reached according to the change characteristics of the third hydraulic pressure value.

[0148] The result acquisition module 360 ​​is used to determine that the mechanical backup of the electronic hydraulic brake system is effective if the pressure relief expectation is achieved.

[0149] The mechanical backup self-checking device 30 detects whether the mechanical brake circuit is blocked normally through the synergistic effect of the circuit control module 310, the pressure building sampling module 320, the first discrimination module 330, the pressure relief control module 340, the second discrimination module 350 and the result acquisition module 360. After the blocking is detected to be normal, the pressure relief of the mechanical brake circuit is checked to verify the efficiency and reliability of the mechanical backup function in a comprehensive and systematic manner. Thus, through precise effectiveness detection, it can effectively ensure that the mechanical backup function of the electronic hydraulic brake system operates well when it is switched to the working mode, significantly improving the overall safety level.

[0150] For the specific implementation and effect of the mechanical backup self-checking device 30, please refer to the description of the implementation of the mechanical backup self-checking method above, such as, for the specific implementation and effect of the loop control module 310, please refer to the description of the relevant content of step 11 above, for the specific implementation and effect of the pressure building sampling module 320, please refer to the description of the relevant content of step 12 above, for the specific implementation and effect of the first discrimination module 330, please refer to the description of the relevant content of step 13 above, for the specific implementation and effect of the pressure relief control module 340, please refer to the description of the relevant content of step 14 above, for the specific implementation and effect of the second discrimination module 350, please refer to the description of the relevant content of step 15 above, for the specific implementation and effect of the result acquisition module 360, please refer to the description of the relevant content of step 16 above, and will not be repeated here.

[0151] In addition, each module in the mechanical backup self-checking device 30 can be implemented in whole or in part by software, hardware, or a combination thereof. Each module can be embedded in or independent of the processor 220 in the electronic device 20 in the form of hardware, or can be stored in the memory 210 of the electronic device 20 in the form of software, so that the processor 220 can call and execute the operations corresponding to each module to implement the mechanical backup self-checking method provided above.

[0152] Based on the same inventive concept as the above-mentioned mechanical backup self-check method, an embodiment of the present invention also provides a controller 110, including a processor 220 and a memory 210, the memory 210 stores a computer program that can be executed by the processor 220, and the processor 220 can execute the computer program to implement the mechanical backup self-check method proposed in the embodiment of the present invention.

[0153] The embodiment of the present invention further provides a storage medium on which a computer program is stored. When the computer program is executed by the processor 220, the mechanical backup self-check method proposed in the embodiment of the present invention is implemented.

[0154] In addition, an embodiment of the present invention further provides a computer program product, which includes computer instructions, wherein when the computer instructions are executed by the processor 220, the mechanical backup self-check method proposed in the embodiment of the present invention is implemented.

[0155] Based on the same concept as the mechanical backup self-check method, refer to Figure 1 The embodiment of the present invention further provides an electronic hydraulic brake system 10, including a controller 110, a main brake circuit 120, an oil tank module 130, a mechanical brake circuit 140 and a wheel end module 150, wherein the main brake circuit 120 and the mechanical brake circuit 140 are respectively connected to the oil tank module 130 and the wheel end module 150.

[0156] The controller 110 is used to execute the mechanical backup self-check method provided above.

[0157] Here, the electronic hydraulic brake system 10 may be an integrated electronic hydraulic brake system, and may be a brake system for a transportation vehicle such as an electric vehicle or a hybrid vehicle.

[0158] In summary, the mechanical backup self-check method, controller and electronic hydraulic brake system provided by the embodiments of the present invention have at least the following beneficial effects:

[0159] 1. Comprehensively and systematically verify the effectiveness and reliability of the mechanical backup function to ensure that the mechanical backup function of the electronic hydraulic brake system operates well when it switches to working mode, significantly improving the overall safety level;

[0160] (ii) By assisting the electric cylinder in building up pressure, the time required for mechanical backup self-inspection is shortened and the inspection efficiency is improved.

[0161] In several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0162] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0163] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk or an optical disk.

[0164] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A mechanical backup self-checking method, characterized in that: A controller applied to an electronic hydraulic brake system, wherein the controller is respectively connected to an electric cylinder, a PSV valve, a CSV valve and an SSV valve of the electronic hydraulic brake system, and the method comprises: Controlling the CSV valve to close, and controlling the PSV valve and the SSV valve to open; When the first displacement of the brake pedal is detected, the electric cylinder is controlled to build pressure, and first pressure building data of the brake pedal and second pressure building data of the electric cylinder are acquired in real time; judging whether the blocking expectation is achieved according to the first pressure building data and the second pressure building data; If yes, then when it is detected that the brake pedal returns to zero position, the CSV valves are controlled to open sequentially, and the third hydraulic pressure value on the electric cylinder side is acquired in real time; judging whether the pressure relief expectation is reached according to the change characteristics of the third hydraulic pressure value; If the pressure relief expectation is reached, it is determined that the mechanical backup of the electronic hydraulic brake system is effective; The first pressure building data includes a pedal displacement value of the brake pedal and a first hydraulic pressure value of the master cylinder, and the second pressure building data includes a piston displacement value and a second hydraulic pressure value of the electric cylinder; The step of judging whether the blocking expectation is achieved according to the first pressure building data and the second pressure building data comprises: Fitting the change relationship between the pedal displacement value and the first hydraulic pressure value to obtain a first curve; Fitting the variation relationship between the piston displacement value and the second hydraulic pressure value to obtain a second curve; Determining whether the first curve and the second curve both conform to their corresponding expected curves; If so, it is determined that the blocking expectation is achieved; A first pressure sensor is provided between the electric cylinder and one of the PSV valves, and an input end of the controller is connected to an output end of the first pressure sensor; The step of controlling the CSV valves to open sequentially and acquiring the third hydraulic pressure value of the electric cylinder side in real time includes: controlling the first CSV valve to open, and sampling the first pressure sensor to obtain a third hydraulic pressure value; When the third hydraulic pressure value is less than the target pressure, the second CSV valve is controlled to open, and the first pressure sensor is continuously sampled to obtain a third hydraulic pressure value; wherein the target pressure is the target value of the electric cylinder pressure build-up; The step of judging whether the pressure relief expectation is reached according to the change characteristics of the third hydraulic pressure value comprises: The time when the second CSV valve is opened is used as the segmentation time; constructing a first hydraulic pressure curve according to the third hydraulic pressure value obtained before the segmentation time, and obtaining a first slope of the first hydraulic pressure curve; constructing a second hydraulic pressure curve according to the third hydraulic pressure value obtained after the segmentation time, and obtaining a second slope of the second hydraulic pressure curve; determining whether the first slope is less than the second slope; If so, it is determined that the pressure relief expectation has been achieved; If not, it is determined that the pressure relief expectation has not been achieved.

2. The mechanical backup self-checking method according to claim 1, characterized in that: After the step of determining that the mechanical backup of the electronic hydraulic brake system is effective, the method further includes: A return-to-zero instruction is sent to the electric cylinder to instruct the electric cylinder to control the piston to move to the zero position, and when it is detected that the piston returns to the zero position, the CSV valve is controlled to close.

3. The mechanical backup self-checking method according to claim 1, characterized in that: After the step of determining whether the blocking expectation is achieved, the method further includes: If the blocking expectation is not achieved, a fault alarm message is generated, and the CSV valve is controlled to be turned on and the PSV valve is controlled to be closed to maintain the mechanical backup braking state.

4. The mechanical backup self-checking method according to claim 1, characterized in that: After the step of judging whether the pressure relief expectation is reached according to the change characteristics of the third hydraulic pressure value, the method further includes: If the pressure relief expectation is not achieved, a fault alarm message is generated, and the PSV valve is controlled to close to prohibit entering the driving state.

5. The mechanical backup self-checking method according to claim 1, characterized in that: The step of controlling the electric cylinder to build up pressure includes: The electric cylinder is controlled to build pressure according to the target pressure, wherein the target pressure is greater than the hydraulic pressure built up when the brake pedal is displaced.

6. A controller, characterized in that: The invention comprises a processor and a memory, wherein the memory stores a computer program executable by the processor, and the processor can execute the computer program to implement the mechanical backup self-check method according to any one of claims 1 to 5.

7. An electronic hydraulic brake system, characterized in that: It comprises a controller as claimed in claim 6, as well as a main brake circuit, an oil tank module, a mechanical brake circuit and a wheel end module, wherein the main brake circuit and the mechanical brake circuit are respectively connected to the oil tank module and the wheel end module.

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