An emergency brake control system based on wet brake reverse oil circuit

Abstract

The present application belongs to the technical field of vehicle brake control, and relates to an emergency brake control system based on a wet brake reverse oil circuit, comprising: a monitoring architecture generation module that acquires standby control oil and vehicle state data; a failure state switching module that releases pilot pressure oil by using differential pressure to drive a reversing valve when pressure loss occurs; a brake gap prefill module that guides pilot pressure oil to eliminate mechanical clearance and make a lock valve standby; a fault fingerprint verification module that matches pressure drop characteristic data and generates an electric control trigger signal; a high-pressure source unlocking module that releases high-pressure brake oil in an accumulator according to the signal to open the lock valve; a brake strategy generation module that calculates a target pressure curve and generates a matched control signal; and a pressure feedback modulation module that controls a regulating valve to dynamically adjust to output a target brake oil pressure. The present application solves the technical problems of existing emergency brake schemes, such as slow response and lack of vehicle dynamic stability cooperative control, under the working condition of main hydraulic system failure.

Description

Technical Field

[0001] This invention belongs to the technical field of vehicle braking control, and relates to an emergency braking control system based on the reverse hydraulic circuit of a wet brake. Background Technology

[0002] The reliability of a vehicle's braking system plays a crucial role in ensuring driving safety. Hydraulic braking systems, characterized by smooth transmission and rapid response, are widely used in wet brake systems. The operation of this type of system depends on the sealing of the hydraulic lines and the structural integrity of the master cylinder. When malfunctions occur, such as a ruptured hydraulic line, a loose joint, or internal leakage in the master brake cylinder, the system's operating pressure will drop rapidly, potentially causing the vehicle to lose its normal braking ability. This situation can easily lead to significant safety hazards under conditions such as high-speed driving or heavy-load downhill driving.

[0003] To address the risk of main braking system failure, existing emergency or backup braking solutions primarily include dual-circuit braking systems, accumulator-based backup systems, and mechanical parking brakes. Dual-circuit braking systems divide the brake lines into two independent circuits, providing partial braking force through the other circuit in the event of a single circuit failure. Accumulator-based backup systems release high-pressure fluid stored in the accumulator via an electronically controlled valve to actuate the brakes upon detecting a loss of pressure in the main system. Mechanical parking brakes provide a means for the driver to manually apply braking force in emergencies. These solutions offer a degree of braking redundancy for the vehicle.

[0004] Existing emergency braking solutions have limitations when dealing with significant pressure loss in the main system. Dual-circuit braking systems are prone to simultaneous failure of both circuits when common components such as the master cylinder or main hydraulic line are damaged. Accumulator-based systems rely on electronic sensor signals for triggering logic, resulting in delays in signal recognition and decision-making. Furthermore, their braking force application lacks a refined adjustment mechanism, making them prone to wheel lock-up and vehicle skidding on low-traction surfaces. Mechanical parking brakes suffer from slow response times and limited braking torque, and similarly lack anti-lock braking adjustment capabilities, making them ill-suited for emergency braking demands during dynamic driving. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides an emergency braking control system based on the reverse hydraulic circuit of a wet brake.

[0006] An emergency braking control system based on a wet brake reversal hydraulic circuit includes: The monitoring architecture generation module is used to obtain backup control fluid with preset pressure from the return pipeline and to obtain vehicle status data including the main brake oil circuit pressure in real time. The failure state switching module is used to monitor the main brake oil circuit pressure. When it is determined that a main brake system pressure loss fault has occurred, it uses the pressure difference formed between the main brake oil circuit after pressure loss and the backup control oil to drive the pressure difference reversing valve to switch and release the backup control oil as pilot pressure oil. The brake clearance pre-filling module is used to guide pilot pressure oil into the brake actuator to push the internal brake piston to eliminate mechanical clearance; at the same time, it diverts part of the pilot pressure oil to the control end of the lock-up valve, so that the lock-up valve remains physically closed and ready to be activated. The fault fingerprint verification module is used to extract the pressure drop characteristic data when a fault occurs, match and verify it with the built-in fault feature library, and generate an electronic control trigger signal after the verification is successful. The high-pressure source unlocking module is used to pressurize the local oil in the control terminal of the lock valve according to the electronic control trigger signal to open the lock valve and release the high-pressure brake fluid accumulated in the high-pressure accumulator. The braking strategy generation module is used to calculate the target braking pressure curve based on vehicle status data and generate a target control signal that matches the curve. The pressure feedback modulation module is used to send the target control signal to the regulating valve to dynamically adjust the flow and pressure of the high-pressure brake fluid and output the target brake fluid pressure to the brake to complete emergency braking.

[0007] In a further embodiment of the present invention, the monitoring architecture generation module is configured to perform the following steps: By obtaining reflux liquid through a pressure-stabilizing and flow-controlling element integrated into the reflux pipeline bypass, a standby control oil with a constant pressure base value is prepared. The backup control fluid and the main brake fluid pressure are applied to the two ends of the differential pressure directional valve core respectively. Under normal operating conditions, the high pressure of the main brake fluid circuit locks the valve core in the position that isolates the backup channel. The vehicle attitude yaw matrix of the current timestamp node is obtained in parallel and packaged with the main brake oil pressure to generate timestamped vehicle state data.

[0008] In a further embodiment of the present invention, the failure state switching module is configured to perform the following steps: Capture the descent gradient value and frequency domain distortion parameter characteristics of the main brake oil circuit pressure in the vehicle status data. When the descent gradient value exceeds the preset failure judgment threshold and the high frequency component in the frequency domain exceeds the limit, verify that the main brake system pressure loss fault has occurred. After a pressure loss fault occurs, the residual pressure force on the valve core end face caused by the main brake oil circuit pressure drops sharply. When the residual pressure force is less than the resultant force of the opposing backup control oil pressure and the return spring thrust, the valve core of the driving differential pressure reversing valve moves to the reverse position. After the valve core moves to the reverse position, it cuts off the main brake oil circuit and connects the backup channel, releasing the backup control oil to form pilot pressure oil for directional delivery.

[0009] In a further embodiment of the present invention, the brake gap pre-filling module is configured to perform the following steps: The pilot pressure oil is guided into the piston end chamber of the brake actuator; The pressure of the pilot oil is used to push the brake piston forward, fill the inherent mechanical gap between the friction components, and generate a pre-braking contact force to eliminate braking shock. A portion of the pilot pressure oil is separated and allowed to enter the pilot control chamber of the lock-up valve. Since the pressure value of the pilot pressure oil is lower than the opening threshold of the built-in spring of the lock-up valve, the valve core remains blocked and in a standby state.

[0010] A further embodiment of the present invention, after the step of generating the pre-braking clamping force, further includes the following steps: The sensor collects data on the volume displacement generated by the brake piston when filling the inherent mechanical gap, as well as the back pressure data when the friction assembly returns. A brake soft-fit correlation stiffness model is constructed by integrating volume displacement data and back pressure data, and then updated to the vehicle state data for underlying benchmark refresh.

[0011] In a further embodiment of the present invention, the fault fingerprint verification module is configured to perform the following steps: By using a bandpass filter to filter out the low-pressure fluctuation signal caused by turbulence in the pressure drop characteristic data, the feature vector of the pressure decay curve is extracted. Substitute the feature vector into the preset algorithm model, and compare it with the built-in fault feature library of pipeline rupture modes using the weighted Euclidean distance. When the distance is less than the preset matching threshold, set an authorized trigger flag. Based on the trigger flag and the built-in exception compensation mapping, an electronically controlled trigger signal with a specific pulse width and voltage amplitude is compiled and generated.

[0012] In a further embodiment of the present invention, the high-voltage source unlocking module is configured to perform the following steps: The electronically controlled trigger signal is fed into the booster solenoid valve to excite the winding and drive the electromagnetic moving iron core to close the oil drain channel and act as a booster plunger to push into the blind path chamber. After the drain channel is closed, the pilot pressure oil remaining in the front blind path is compressed by the volume of the electromagnetic moving iron core, which induces local electromagnetic work to increase the pressure, and obtains a local over-limit hydraulic pressure that is greater than the opening threshold of the built-in spring of the lock valve. By utilizing local over-limit hydraulic pressure to overcome spring resistance, the valve core of the lock-up valve is forced to complete the opening operation, opening the outlet of the energy storage chamber and thus releasing the high-pressure brake fluid.

[0013] In a further embodiment of the present invention, the braking strategy generation module is configured to perform the following steps: The dynamic linear velocity slip ratio of each wheel is calculated based on the wheel speed sensor data, and is used as the wheel slip ratio. By extracting yaw rate and lateral acceleration from vehicle state data, vehicle yaw stability parameters that measure the magnitude of vehicle sideslip drift are separated through matrix calculation. By combining wheel slip ratio and vehicle yaw stability parameters, multi-condition nonlinear constraint fitting calculations are performed to solve the target braking pressure curve that prevents wheel lock-up and vehicle instability, and then converted into the corresponding target control signal through pulse width modulation coding.

[0014] In a further embodiment of the present invention, the regulating valve is a proportional regulating valve connected in series in the high-pressure oil circuit, the target control signal is a target PWM control signal, and the pressure feedback modulation module is configured to perform the following steps: The target PWM control signal is continuously applied to both ends of the induction coil of the proportional control valve to control the valve core opening. The high-frequency orbital displacement of the valve core dynamically shears and adjusts the flow area of ​​the high-pressure brake fluid entering the fluid flow pipeline, filters out pressure peaks, and reshapes the output smooth target brake fluid pressure. The target brake oil pressure is continuously applied to the brake, and anti-lock slip correction is performed based on vehicle status data during the final friction locking interference process.

[0015] A further aspect of the present invention includes the following steps after emergency braking is completed: Collect residual pressure information in the pipeline during the pressure balance and stable shutdown phase, as well as the brake piston reset stroke coordinates transmitted from the end caliper; The current residual pressure information is compared with the discrete data that has deviated from the reset stroke coordinate. This discrete data is stored as the residual pressure correction baseline and used to compensate for the initial pressure threshold of the next emergency braking control command.

[0016] In summary, the present invention has the following beneficial technical effects: 1. This invention achieves primary circuit switching based on a hydrodynamic mechanism by constructing a backup control fluid based on a hydraulic return pipeline and utilizing the pressure difference formed between the main braking circuit and the backup control fluid when the main braking circuit loses pressure to drive a differential pressure reversing valve. This design reduces the reliance on signal detection and command processing of the electronic control unit in the initial stage of emergency response, shortens the initial reversing response time of the emergency braking system in the event of a failure, and helps to quickly activate the backup channel after the main braking system loses pressure.

[0017] 2. This invention employs a two-stage emergency braking mechanism. After the oil circuit switches, pilot pressure oil is first guided into the brake actuator to push the piston, thereby filling the inherent mechanical gap between the friction pairs and generating a pre-braking clamping force. After the pre-filling action is completed, the brake fluid in the high-pressure accumulator is released via an electronic control signal. This two-stage control logic mitigates the fluid shock generated when high-pressure fluid directly acts on the braking mechanism with mechanical gaps, improves the smoothness of emergency braking intervention, and helps reduce mechanical shock damage to braking components and the resulting vehicle vibration.

[0018] 3. During the release of high-pressure braking energy, this invention calculates the target braking pressure curve by real-time acquisition of wheel slip data and vehicle yaw attitude data, and generates a corresponding PWM control signal to drive the proportional regulating valve in the high-pressure oil circuit. This closed-loop regulation mechanism can dynamically control the flow and pressure of the high-pressure brake fluid, ensuring that the hydraulic pressure output to the brake conforms to the target curve change, thereby providing the vehicle with the ability to coordinate anti-lock braking adjustment and vehicle stability control under emergency braking conditions.

[0019] 4. This invention introduces a fault fingerprint verification mechanism before triggering the high-pressure source unlocking. It extracts pressure drop characteristic data during the main system's pressure loss process and compares it with a built-in pipeline rupture fault feature database. A trigger flag is set only after a successful match. This verification step helps the system distinguish between transient abnormal signals caused by road bumps or sensor interference and actual physical damage to the oil circuit, improving the accuracy of the system's main brake pressure loss fault determination and reducing the probability of false triggering of the emergency braking procedure. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings are used to provide a further understanding of the present invention.

[0021] Figure 1 This is a schematic diagram of the framework in the embodiments of this application.

[0022] Figure 2 This is a flowchart illustrating an embodiment of this application.

[0023] Figure 3 This is a schematic diagram of the characteristic curve for determining the main oil circuit pressure loss fault in the embodiments of this application.

[0024] Figure 4 This is a schematic diagram of the two-stage emergency braking pressure response curve in an embodiment of this application. Detailed Implementation

[0025] The following is in conjunction with the appendix Figures 1-4 A preferred description of the present invention is provided below.

[0026] See attached document Figures 1-4 This invention proposes an emergency braking control system based on the reverse hydraulic circuit of a wet brake, comprising the following modules: The monitoring architecture generation module is used to obtain backup control fluid with preset pressure from the return pipeline and to obtain vehicle status data including the main brake oil circuit pressure in real time. The failure state switching module is used to monitor the main brake oil circuit pressure. When it is determined that a main brake system pressure loss fault has occurred, it uses the pressure difference formed between the main brake oil circuit after pressure loss and the backup control oil to drive the pressure difference reversing valve to switch and release the backup control oil as pilot pressure oil. The brake clearance pre-filling module is used to guide pilot pressure oil into the brake actuator to push the internal brake piston to eliminate mechanical clearance; at the same time, it diverts part of the pilot pressure oil to the control end of the lock-up valve, so that the lock-up valve remains physically closed and ready to be activated. The fault fingerprint verification module is used to extract the pressure drop characteristic data when a fault occurs, match and verify it with the built-in fault feature library, and generate an electronic control trigger signal after the verification is successful. The high-pressure source unlocking module is used to pressurize the local oil in the control terminal of the lock valve according to the electronic control trigger signal to open the lock valve and release the high-pressure brake fluid accumulated in the high-pressure accumulator. The braking strategy generation module is used to calculate the target braking pressure curve based on vehicle status data and generate a target control signal that matches the curve. The pressure feedback modulation module is used to send the target control signal to the regulating valve to dynamically adjust the flow and pressure of the high-pressure brake fluid and output the target brake fluid pressure to the brake to complete emergency braking.

[0027] In one embodiment of the present invention, the monitoring architecture generation module is used to perform the following steps: By obtaining reflux liquid through a pressure-stabilizing and flow-controlling element integrated into the reflux pipeline bypass, a standby control oil with a constant pressure base value is prepared. The backup control fluid and the main brake fluid pressure are applied to the two ends of the differential pressure directional valve core respectively. Under normal operating conditions, the high pressure of the main brake fluid circuit locks the valve core in the position that isolates the backup channel. The vehicle attitude yaw matrix of the current timestamp node is obtained in parallel and packaged with the main brake oil pressure to generate timestamped vehicle state data.

[0028] Specifically, a backup control fluid is established based on the hydraulic system's return line by using pressure-stabilizing and flow-controlling elements integrated into the vehicle's hydraulic system. It should be noted that the backup control fluid is a constant low-pressure hydraulic potential energy zone formed by adding a bypass booster and pressure stabilizing device to the low-pressure return manifold of the vehicle's wet braking system. Its pressure value is set and stably maintained at a specific standby pressure. In this embodiment, The preferred value range is between 0.3MPa and 0.5MPa. The setting of this value is based on the following: its lower limit must be sufficient to overcome the inertia of the valve and the liquid in subsequent steps, ensuring that it can serve as an effective trigger signal source after the main system loses pressure; its upper limit must ensure that the pressure does not generate a thrust on the brake piston sufficient to overcome the return spring force, thereby avoiding unnecessary braking drag during normal driving.

[0029] The pressure-regulating and flow-controlling element is specifically a bypass assembly consisting of a miniature gear pump, a relief valve, and a miniature accumulator, which draws oil from the low-pressure return main. Hydraulic oil is drawn from the interface, pressurized by a micro gear pump, and then supplied at a set pressure. The overflow valve limits the pressure, forming a fluid field with a stable pressure base value. Excess oil returns to the main oil tank through the overflow valve. This fluid field is injected into and maintained in a modified brake return line through a check valve, thereby completing the preparation of the initial state of hydraulic potential energy.

[0030] The control system will adjust the pressure of the backup control oil. Together with the main brake oil pressure transmitted from the main system pipeline under normal operation The pressure is applied in opposite directions to the two pressure control ports of the differential pressure directional valve. It should be understood that the differential pressure directional valve is a differential pressure-driven spool valve used to directly convert the passively monitored pressure signal difference into the macroscopic physical displacement of the valve core. This converter is essentially a differential pressure-driven two-position spool valve, with the two ends of the main valve core connected to these two pressure fields respectively.

[0031] Under normal operating conditions, due to Much larger The pressure difference between the two forces will push the main valve core to its anti-reverse limit position and keep it locked. In this position, the valve body structure completely isolates the port of the backup hydraulic passage, forming a normal closed-loop blocking function. At the same time, the vehicle's electronic control unit, through its built-in firmware driver, acquires real-time scalar values ​​measured by the pressure sensor installed in the main brake fluid circuit at a preset sampling frequency. Among them, the main brake oil circuit pressure This refers to the real-time hydraulic pressure generated by the main brake pump and used to drive the operational brakes. Its value is a lower system pressure held value in the non-braking state, rising as needed during braking. Additionally, high-frequency pickup refers to the sampling frequency of the pressure sensor signals by the electronic control unit, typically set to 20kHz. This frequency is based on the analysis of the transient pressure change characteristics of the hydraulic system, ensuring the capture of millisecond-level pressure collapse events and high-frequency fluid distortion noise.

[0032] At the same time, the vehicle's electronic control unit also receives the vehicle attitude yaw matrix transmitted from the vehicle's angular momentum module. Here, the vehicle attitude yaw matrix... This data is acquired in real-time from the onboard inertial measurement unit (IMU), typically represented as a 3×3 rotation matrix describing the rotational relationship between the vehicle's coordinate system and the navigation coordinate system. It includes attitude information such as yaw, pitch, and roll, with yaw rate being a key parameter for assessing vehicle stability. The electronic control unit (ECU) integrates these heterogeneous real-time data streams and aligns them with timestamps to generate a structured dataset, representing the vehicle's real-time dynamic state data. Vehicle status data It is a data structure dynamically constructed in the memory of the electronic control unit, and its form is a collection of heterogeneous data tuples: This collection encapsulates items at the same timestamp. The main oil circuit pressure scalar value and the vehicle attitude matrix provide a unified, real-time updated input data source for the entire emergency braking control logic, and provide an immediate benchmark for failure judgment in subsequent steps.

[0033] In one example of the present invention, it is assumed that at a certain moment... The vehicle is in normal driving condition and is not braking. At this time, the integrated pressure regulating and flow controlling element has established a pressure of [pressure value missing] in the designated return oil line section. The backup control fluid. Meanwhile, the main braking system lines maintain a baseline filling pressure, therefore the pressure sensor mounted on it measures the main braking fluid pressure. for These two pressure values ​​are simultaneously applied to both ends of the differential pressure directional valve spool. Because... Much larger The valve core is securely locked at the anti-reverse end, closing the backup passage. At the same time... The electronic control unit's firmware driver reads a pressure sensor reading of 1.5 MPa and receives the vehicle attitude yaw matrix from the inertial measurement unit via the CAN bus. This matrix shows a yaw rate of 0.01 rad / s, indicating a minor heading adjustment. The electronic control unit then timestamps the current data. The main oil circuit pressure value of 1.5MPa and the vehicle attitude yaw matrix containing yaw rate information are packaged together to form a vehicle state data instance, which is stored in the loop data buffer as a baseline snapshot of the vehicle's dynamic stability state at that moment.

[0034] In one embodiment of the present invention, the failure state switching module is used to perform the following steps: Capture the descent gradient value and frequency domain distortion parameter characteristics of the main brake oil circuit pressure in the vehicle status data. When the descent gradient value exceeds the preset failure judgment threshold and the high frequency component in the frequency domain exceeds the limit, verify that the main brake system pressure loss fault has occurred. After a pressure loss fault occurs, the residual pressure force on the valve core end face caused by the main brake oil circuit pressure drops sharply. When the residual pressure force is less than the resultant force of the opposing backup control oil pressure and the return spring thrust, the valve core of the driving differential pressure reversing valve moves to the reverse position. After the valve core moves to the reverse position, it cuts off the main brake oil circuit and connects the backup channel, releasing the backup control oil to form pilot pressure oil for directional delivery.

[0035] The system continuously monitors the operating status of the main brake fluid circuit using vehicle status data. In the event of a sudden event such as a main hydraulic line rupture or pump failure, the electronic control unit (ECU) will capture the high-frequency descent gradient and envelope frequency domain distortion parameters exhibited by the main brake fluid circuit pressure. Specifically, the ECU analyzes the continuously acquired real-time scalar values ​​of the main brake fluid circuit pressure. Perform a difference operation to calculate its rate of change over time, i.e., the pressure gradient. As shown in the following formula: In the formula, the high-frequency descent gradient is... This is a physical quantity characterizing the rate of pressure collapse in the main brake hydraulic circuit, measured in MPa / s. If this gradient value exceeds a preset failure threshold within a short period... The corresponding failure determination gradient threshold It is a negative value, usually calibrated based on simulation and experimental data of oil pipe rupture scenarios of different diameters, preferably between -80MPa / s and -150MPa / s, to distinguish between normal braking pressure relief and pipeline leakage failure. Furthermore, through... Fast Fourier Transform analysis of the signal revealed a significant increase in high-frequency noise components in its spectrum, exceeding the frequency domain characteristic envelope under normal operating conditions. Here, the envelope frequency domain distortion parameter is a characteristic quantity obtained by analyzing the energy distribution of the pressure signal spectrum. When the pipeline ruptures, the fluid changes from laminar to turbulent flow, generating broadband noise, which leads to an abnormal increase in the high-frequency energy of the signal spectrum. This parameter quantifies the degree of this distortion.

[0036] When the above situation is detected, the control system verifies a main braking system pressure loss fault caused by an irreversible pump failure or oil pipe rupture. It should be understood that the main braking system pressure loss fault is a logic flag; this flag is only set to true when the absolute value of the pressure gradient and the frequency domain distortion parameter simultaneously exceed their respective thresholds. This effectively avoids misjudgments caused by momentary sensor interference or severe vibrations. After this state is confirmed, the differential pressure directional valve performs a microsecond-level hydrodynamic self-cutoff switching action. This is because the main braking system pressure loss fault causes a pressure drop in the main braking oil circuit acting on one end of the main valve core. The residual pressure rapidly decays to near ambient pressure. This creates a physical window environment. In this invention, the fluid dynamic self-cut-off switching action refers to a purely mechanical hydraulic response process, specifically: when the main oil circuit loses pressure, causing the left end of the main valve core to experience a decrease in force, without the intervention of electronic sensor signals, the mechanical thrust of the hydraulic pressure combined with the reset spring established by the backup control oil at the right end of the main valve core is instantaneously greater than the residual pressure resistance at the left end, thereby directly pushing the main valve core to generate mechanical displacement, closing the main oil circuit interface and opening the backup oil circuit interface.

[0037] At this time, the original high voltage The other end of the force system being suppressed is the stable pressure provided by the backup control fluid. And the mechanical thrust released by the rear spring installed inside the differential pressure directional valve. The rear spring is a pre-compressed helical spring installed on the low-pressure side of the main valve core. Its function is to provide an initial, hydraulically independent driving force when the main system pressure collapses, ensuring that the valve core can overcome static friction to initiate the reversing process. The two together form a resultant force. The resultant force overcomes the reverse residual pressure, and its condition for action can be expressed as: in The effective force-bearing area of ​​the main valve core, This represents the static frictional resistance to the movement of the valve core.

[0038] Driven by this force, the main valve core is pushed away from its normal position and moved to the reverse position. This physical displacement simultaneously achieves two actions: disconnecting the connection port with the damaged main brake oil line and instantly opening the previously isolated downstream emergency interface passage. With the establishment of this emergency interface passage, the hydraulic oil previously stored in the backup control fluid is released instantly, forming a pilot pressure oil with a clear pressure front, which propagates downstream along the backup pipeline.

[0039] It is worth mentioning that the pilot pressure oil has a pressure close to The hydraulic flow is not used for direct braking, but rather as a rapidly transmitted physical signal to trigger subsequent emergency braking and pre-fill the brake gap.

[0040] In a specific example of the present invention, at time The vehicle experienced a sudden main brake line rupture while in motion. The electronic control unit detected a sudden drop in main brake fluid pressure from the normal value of 1.5 MPa to 0.1 MPa within 5 ms. This 0.1 MPa represents the instantaneous residual gauge pressure within the ruptured system line due to flow resistance. (See [link to relevant documentation]). Figure 3 The system calculates the pressure gradient based on this. The absolute value of this 280 MPa / s is far greater than the system's set failure threshold of 100 MPa / s. Simultaneously, spectral analysis of the pressure signal shows that the high-frequency noise energy exceeds the limit, leading the system to determine that it has entered a main braking system pressure loss fault state. In this state, the pressure acting on the main valve core of the differential pressure directional valve reverses. Assume the effective force-bearing area of ​​the valve core... It is 1.5cm 2 Rear-mounted spring thrust The static friction resistance is 15N. The resultant force driving the valve core to reverse is 10N. for The residual resistance in the opposite direction is... Because 75N > 25N, the main valve core is pushed by the powerful combined force, instantly completing the reversal. This action cuts off the main oil circuit at 0.1MPa and simultaneously opens the emergency passage, allowing the hydraulic oil in the backup control oil at 0.4MPa to be released, forming a pilot pressure oil with a pressure front of 0.4MPa, which then flows into the downstream backup pipeline.

[0041] In one embodiment of the present invention, the brake gap pre-filling module is used to perform the following steps: The pilot pressure oil is guided into the piston end chamber of the brake actuator; The pressure of the pilot oil is used to push the brake piston forward, fill the inherent mechanical gap between the friction components, and generate a pre-braking contact force to eliminate braking shock. A portion of the pilot pressure oil is separated and allowed to enter the pilot control chamber of the lock-up valve. Since the pressure value of the pilot pressure oil is lower than the opening threshold of the built-in spring of the lock-up valve, the valve core remains blocked and in a standby state. The sensor collects data on the volume displacement generated by the brake piston when filling the inherent mechanical gap, as well as the back pressure data when the friction assembly returns. A brake soft-fit correlation stiffness model is constructed by integrating volume displacement data and back pressure data, and then updated to the vehicle state data for underlying benchmark refresh.

[0042] Pilot pressure oil flows through a backup channel connected by a differential pressure directional valve to fill multiple two-stage brake actuators distributed at the wheel ends of different axles. A two-stage brake actuator is a composite brake actuator unit integrating a brake piston, a high-pressure accumulator, and a multi-stage control valve system, designed to achieve two-stage pressure application during emergency braking.

[0043] Pilot hydraulic oil propagates at the speed of sound in the fluid medium, rapidly flowing back into the actuator through the main inlet and filling the braking end chamber inside. Upon entering the chamber, the initial hydraulic potential energy of the pilot hydraulic oil, i.e., its pressure... Acting on the brake piston, it generates an initial thrust. This thrust is sufficient to overcome the piston's return spring force and sealing friction resistance, propelling the piston body within the chamber until it completely fills the inherent minute mechanical gap between the brake friction plate and the brake disc, which is caused by manufacturing tolerances and wear. This generates a shock-free pre-braking contact force by establishing a soft-touch physical association between system components. In this invention, the soft-touch physical association refers to a physical standby state where pilot pressure oil pushes the brake piston to move, causing the brake friction pads to just contact the brake disc and eliminate the mechanical gap between them, typically 0.1~0.5mm. However, the brake line pressure generated at this point is insufficient to produce an effective braking torque to decelerate the wheels.

[0044] In this embodiment, the pre-braking clamping force It is the pressure of the pilot pressure oil The effective area directly acting on the brake piston The initial contact force generated is calculated using the following formula: The purpose of this force is not to generate effective braking torque, but rather to preemptively eliminate all transmission backlashes, ensuring the friction pads adhere to the brake disc and creating conditions for smooth intervention of subsequent high-pressure braking. After generating the aforementioned pre-braking contact force, the control system collects data on the volumetric displacement of the brake piston as it fills the inherent mechanical backlashes, as well as the back pressure data during the return stroke of the friction components, using sensors that typically include, but are not limited to, piston displacement sensors or flow meters. Subsequently, the system integrates the volumetric displacement data and back pressure data, employs an algorithm to construct a brake soft-fit correlation stiffness model, and updates this model to the vehicle state data for underlying benchmark updates, thereby providing adaptive dynamic parameters for precise control of subsequent emergency pressure.

[0045] In one embodiment of the present invention, a brake soft-fit correlation stiffness model is constructed by fusing volume displacement data and back pressure data, specifically through the following linear or polynomial fitting equations: The system continuously collects the increase in hydraulic oil volume displacement during the piston clearance elimination process. Corresponding pipeline back pressure increment System stiffness If the nonlinear deformation of the sealing ring is taken into account, the stiffness model is further modified as follows: The coefficients a, b, and c are obtained in real time by fitting the currently collected displacement and back pressure data using the least squares method. This model reflects the actual elastic characteristics of the current brake and is used to guide the initial injection rate of high-pressure oil during subsequent PWM control.

[0046] In one embodiment of the present invention, the underlying reference refresh refers to the vehicle electronic control unit writing the calculated initial brake engagement bias data, such as the initial piston displacement and basic back pressure value, into a non-volatile memory, overwriting the factory default zero-point calibration value. During the next emergency braking operation, the control program will use this overwritten bias data as a starting point to calculate the PWM duty cycle, thereby eliminating the accumulated error caused by mechanical wear.

[0047] While performing the above actions, a flow channel branching off from the main inlet bypass guides the pilot pressure oil to the pilot control chamber of the independently structured lock-up valve.

[0048] Among them, the shut-off valve is a mechanical normally closed valve, and the preload of its internal spring is precisely calibrated to set a specific opening pressure, namely the spring force dead point threshold. The setting of this threshold must meet certain conditions. The typical setting range is 0.6 MPa to 0.8 MPa. This value is set based on ensuring the standby pressure. While ensuring that high-voltage release is never accidentally triggered, the threshold must not be too high, so that it can be easily exceeded in subsequent steps with a small electronic boost command.

[0049] Due to the pressure of the pilot pressure oil The pressure applied to the end face of the control plunger of the locking valve is lower than the opening pressure threshold of the preset spring force inside the locking valve, i.e., the spring force dead point threshold. Therefore, insufficient thrust cannot be generated to compress the spring and move the valve core. As a result, the valve core of the locking valve remains in its normally closed position, the high-pressure energy storage channel remains isolated, and the locking valve remains physically closed and ready to engage. It should be understood that this physically closed ready state refers to an intermediate state in which the braking system has entered, in which the brake clearance has been eliminated, but the high-pressure braking energy source is still locked by the physical valve, and the entire system is in a safe-ready state.

[0050] For example, pilot pressure oil at 0.4 MPa travels along a backup line to a two-stage brake actuator at a wheel. The effective area of ​​the brake piston inside... 25cm 2The inherent mechanical gap between the friction pads and the brake disc is 0.6 mm. The resistance of the piston return spring in the fully engaged position is approximately 500 N, and the static friction of the sealing structure is approximately 200 N. After the pressure wave enters the brake chamber, it generates a thrust on the piston. .Should The thrust drives the piston to move 0.6 mm, causing the friction pads to fully engage with the brake disc, thus generating a pre-braking contact force of 300 N. Simultaneously, this 0.4 MPa pressure wave is diverted to the control port of the locking valve. Assume the spring force dead point threshold of this locking valve... The pressure is set to 0.7 MPa. Because the pressure acting on the control plunger of the locking valve (0.4 MPa) is lower than its opening threshold of 0.7 MPa, the valve cannot be opened, and the valve core remains in the normally closed position. Therefore, the system enters a physically closed standby state, meaning the brake pads are engaged, but the energy release channel of the high-voltage accumulator stored inside the actuator is physically locked.

[0051] In one embodiment of the present invention, the fault fingerprint verification module is configured to perform the following steps: By using a bandpass filter to filter out the low-pressure fluctuation signal caused by turbulence in the pressure drop characteristic data, the feature vector of the pressure decay curve is extracted. Substitute the feature vector into the preset algorithm model, and compare it with the built-in fault feature library of pipeline rupture modes using the weighted Euclidean distance. When the distance is less than the preset matching threshold, set an authorized trigger flag. Based on the trigger flag and the built-in exception compensation mapping, an electronically controlled trigger signal with a specific pulse width and voltage amplitude is compiled and generated.

[0052] Specifically, after confirming that the shut-off valve remains physically closed and ready to engage, the system initiates a retrieval and analysis of data recorded within the main control unit to determine the authenticity and irreversibility of the fault. The electronic control unit first extracts a complete dataset from the memory buffer recording main braking system pressure loss faults. This dataset contains high-frequency sampling points throughout the pressure range from normal to critical.

[0053] To filter out the low-pressure fluctuations that may occur under normal operating conditions such as vehicle travel on rough roads, the control algorithm uses a bandpass filter to preprocess the original pressure signal, filtering out interference signals that do not match the frequency characteristics of actual pipeline ruptures. Next, the algorithm extracts a curve fingerprint representing the pressure extreme value slip from the filtered signal, namely the feature vector of the pressure decay curve. This feature vector is a multi-dimensional feature vector. Each component is a parameter that quantifies the dynamic characteristics of the stress collapse process, such as... For total pressure drop, For duration, this fingerprint is a feature vector generated by calculating several key quantitative indicators of the pressure collapse phase, including but not limited to the total pressure drop magnitude, the time to reach the lowest pressure, the nonlinear curvature of the pressure drop curve, and the maximum negative gradient value. It is used to transform transient pressure changes into comparable mathematical objects to identify whether the current event is genuine physical damage, rather than sensor transient artifacts caused by strong electromagnetic fields.

[0054] Subsequently, the system performs dimensionless normalization on the feature vectors of the extracted real-time pressure decay curves, and then matches them with the system's built-in, fixed pipeline rupture fault feature library. It should be noted that the pipeline rupture fault feature library is a database stored in the non-volatile memory of the electronic control unit, containing multiple sets of standard fingerprint vectors. Each group corresponds to a specific failure mode obtained through extensive experiments or simulations. This feature library pre-stores various known pipeline leakage failure modes, such as standard fingerprint vectors corresponding to different degrees of pipe rupture or pump jamming. The comparison process uses a weighted Euclidean distance algorithm, calculated as follows: In the formula, It is the first The weight coefficients of each feature reflect the importance of different features in fault diagnosis. These weight coefficients are obtained offline through expert experience or machine learning algorithms. If the calculated distance... Less than the preset matching threshold If the current actual fault event is determined to highly match a certain damage mode in the database, the system will establish an irreversible failure trigger flag. It should be understood that the irreversible failure trigger flag is a specific bit in the electronic control unit's memory, and its change from 0 to 1 is the only hardware-level authorization signal to grant access to subsequent high-voltage braking procedures. Setting this flag will wake up and grant the localized electronic control compensation subroutine firmware the highest running privileges.

[0055] Regarding the calculation of feature weight coefficients, those skilled in the art can use pre-trained lightweight neural networks, such as BP neural networks, with the input layer being the total pressure drop and the maximum negative gradient, two hidden layers, and the output layer being the matching probability weights for various fault modes. As an alternative or preferred implementation, the weight coefficients can also be directly retrieved from a two-dimensional lookup mapping table formed by extensive benchtop testing. For example, when the ambient temperature is below 0°C and the pressure drop gradient is extremely rapid (e.g., absolute value > 200 MPa / s), the total pressure drop feature is assigned a weight of 0.6, and the duration feature a weight of 0.4; under normal temperature conditions, they are assigned equal weights of 0.5 and 0.5 respectively. A built-in database is formed based on these rules for program calls.

[0056] The localized electronic control compensation subroutine firmware is a dedicated, isolated, and protected emergency code that remains dormant under normal operating conditions to prevent accidental invocation. Once activated, this firmware retrieves the corresponding anomaly compensation mapping from a pre-defined lookup table based on the matched specific damage mode and instantly compiles and generates an electronic control trigger signal with a specific pulse width and voltage amplitude. This instruction manifests as a boost control pulse signal, a series of electrical signals with specific voltage amplitude, pulse width, and frequency. Its design goal is to precisely inject energy into the small-volume control oil chamber in a very short time in the next stage, and this energy is sent to the drive pin of the boost solenoid valve integrated within the two-stage brake actuator. The boost solenoid valve is a high-response solenoid valve used to achieve rapid local boosting within the pilot control blind channel of the locking valve. The system uses this to construct an electronic control trigger signal to overcome and break the physically pending unlocking conditions. The electronic control trigger signal describes the functional attributes of this electrical signal sequence, indicating its output in the electronic control field, with the aim of triggering a phase transition or state transition in the fluid dynamics field.

[0057] For example, the system has entered a physically pending unlock condition. At this point, the electronic control unit begins analyzing the pressure collapse data that led to this state. It extracts a four-dimensional feature vector from the recorded 5ms process data of the pressure dropping from 1.5 MPa to 0.1 MPa as the feature vector of the pressure decay curve, for example... The fourth parameter is a coefficient describing the nonlinearity of the curve. The system's built-in pipeline rupture fault feature database contains a record corresponding to the rupture of main oil pipe No. 2, and its standard fingerprint is... Assuming all feature weights All values ​​are 1, and the feature data has been normalized. The calculated weighted Euclidean distance is... The value is 0.08. This is the system-set matching threshold. The value is 0.15. Since 0.08 < 0.15, the match is successful. The electronic control unit immediately sets the irreversible failure trigger flag to 1. This flag change wakes up the localized electronic control compensation subroutine firmware. Based on the matched No. 2 main oil pipe rupture mode, the firmware retrieves the corresponding instruction parameters of 5V voltage and 20ms pulse width from the lookup table and immediately compiles and generates a single-pulse voltage signal. This 5V, 20ms electrical pulse is sent to the pin of the booster solenoid valve, constituting the electronic control trigger signal, preparing to break the 0.7MPa spring force dead point threshold in the next step.

[0058] In one embodiment of the present invention, the high-voltage source unlocking module is used to perform the following steps: The electronically controlled trigger signal is fed into the booster solenoid valve to excite the winding and drive the electromagnetic moving iron core to close the oil drain channel and act as a booster plunger to push into the blind path chamber. After the drain channel is closed, the pilot pressure oil remaining in the front blind path is compressed by the volume of the electromagnetic moving iron core, which induces local electromagnetic work to increase the pressure, and obtains a local over-limit hydraulic pressure that is greater than the opening threshold of the built-in spring of the lock valve. By utilizing local over-limit hydraulic pressure to overcome spring resistance, the valve core of the lock-up valve is forced to complete the opening operation, opening the outlet of the energy storage chamber and thus releasing the high-pressure brake fluid.

[0059] Specifically, a potential pulse with specific parameters is input to the control winding of the booster solenoid valve integrated within the two-stage brake actuator. It should be noted that the booster solenoid valve is a normally open miniature solenoid valve, which provides a small bypass drain channel when not energized to ensure that the pressure within the pilot control blind channel remains stable. It also prevents pressure drift caused by factors such as temperature changes. The valve closes after power is applied, achieving a sealed pressurization.

[0060] The input of an electrical signal energizes the solenoid valve winding, rapidly creating an enhanced magnetic field within it and triggering an excitation and engagement action. This magnetic force acts on the moving and stationary iron cores within the valve, overcoming the resistance of their return springs and driving the moving iron core to move at high speed, instantly closing the drain channel that previously connected the pilot control blind passage at the front end of the locking valve to the low-pressure return oil chamber. After closing the channel, the moving iron core, driven by the residual electromagnetic stroke, acts as a miniature booster plunger, further forcibly pushing into the closed pilot control blind passage, thus forcibly compressing the hydraulic oil that was originally stagnant in the blind passage.

[0061] By using electromagnetic work to input energy into the closed fluid, the local oil pressure in the pilot control chamber rises rapidly. This physical phase change process creates local over-limit hydraulic pressure that exceeds the predetermined constant load value of the safety opening spring. It should be understood that local over-limit hydraulic pressure... This is the final result of localized pressurization, and its value satisfies... This pressure is typically achieved within milliseconds after the solenoid valve actuates. The formation of this pressure is a result of the pure coupling of fluid mechanics and electromagnetism, enabling the actuation of a macroscopic mechanical valve with minimal electrical power. This localized over-limit hydraulic pressure... The force applied directly to the end face of the control plunger of the shut-off valve has exceeded the valve's preset spring force dead point threshold. .

[0062] Under this pressure-driven overcoming of spring resistance, the spring of the locking valve is forcibly compressed, and the valve core is pushed, realizing a single opening operation of the valve body. The opening operation of the locking valve refers to a one-time non-proportional switching action completed by the valve core under hydraulic pressure, from fully closed to fully open. Its characteristics are speed and decisiveness, minimizing throttling losses and response delays of the high-pressure oil. This reversing action instantly connects the core passage previously blocked by the valve, directly linking the outlet of the energy storage chamber with the piston chamber of the brake actuator. With the opening of the core passage, the energy previously stored in the energy storage chamber, i.e., the high-pressure micro accumulator, a pressure vessel pre-filled with high-pressure hydraulic oil by a system hydraulic pump or a dedicated filling device and then sealed, has its internal pressure... The pressure is much higher than the normal operating pressure of the system, typically reaching 15MPa to 20MPa, to ensure that sufficient emergency braking torque can be provided under any operating conditions. The hydraulic oil is pre-loaded and maintained at extremely high pressure, and then released to form high-pressure brake fluid carrying huge energy. High-pressure brake fluid is a dynamic description of the hydraulic oil that bursts out from the high-pressure accumulator, emphasizing its transient characteristics of high pressure, fast flow rate and short action time. This fluid rushes rapidly to the brake piston, ready to perform the final powerful braking.

[0063] For example, the 5V, 20ms electronic trigger signal from the electronic control unit is applied to the booster solenoid valve. The booster solenoid valve coil is energized, the moving iron core actuates, closing the return oil micro-orifice of the pilot control tactile chute, and under the continuous push of its own electromagnetic force, it acts as a plunger to compress the closed micro-cavity. At this time, the volume of hydraulic oil in the tactile chute is forcibly compressed, causing the internal pressure to rapidly rise from a baseline of 0.4MPa. After approximately 15ms of boosting, the internal pressure is raised to its peak value, forming a localized over-limit hydraulic pressure. The pressure of 1.0 MPa applied to the control end of the shut-off valve significantly exceeds the valve's 0.7 MPa spring force dead point threshold. Therefore, the shut-off valve spring is compressed, the valve core is pushed open, and the high-pressure passage is instantly opened. High-pressure hydraulic oil stored in the energy storage chamber at 16 MPa is immediately and rapidly released through the opened valve port, forming high-pressure brake fluid. This powerful 16 MPa flow rushes towards the brake piston, which has already been in contact with the brake disc in the previous step, preparing to apply braking force. At this point, the system has completed the entire process of converting an electrical signal into the release of high-pressure fluid.

[0064] In one embodiment of the present invention, the braking strategy generation module is configured to perform the following steps: The dynamic linear velocity slip ratio of each wheel is calculated based on the wheel speed sensor data, and is used as the wheel slip ratio. By extracting yaw rate and lateral acceleration from vehicle state data, vehicle yaw stability parameters that measure the magnitude of vehicle sideslip drift are separated through matrix calculation. By combining wheel slip ratio and vehicle yaw stability parameters, multi-condition nonlinear constraint fitting calculations are performed to solve the target braking pressure curve that prevents wheel lock-up and vehicle instability, and then converted into the corresponding target control signal through pulse width modulation coding.

[0065] The control system retrieves and integrates real-time speed measurements from wheel speed sensors located on both sides of each independent axle via the vehicle's bus network. It then measures the linear velocity of the two wheels on the same axle. and And take into account the vehicle speed for processing. Typically, the speed is taken from the non-driving wheel speed or estimated via GPS / IMU. The system calculates the dynamic linear velocity slip ratio of each wheel in real time using the following formula. : It should be noted that wheel slip ratio It is a key indicator for evaluating the utilization of longitudinal force by the tire. On dry asphalt roads, its optimal value is usually between 15% and 20%. Exceeding this range, the braking force drops sharply. By calculating and comparing the deviation of the slip ratio of different wheels and monitoring its changing trend, the system can accurately extract the wheel slip ratio, which describes the boundary of the vehicle end grip capability. It should be understood that what is extracted here is the tire rotation slip edge trend factor, which is a comprehensive description of the wheel slip ratio. It includes not only the current slip ratio value but also the rate of change of the slip ratio, i.e., slip acceleration, to predict whether the wheel is about to lock up.

[0066] At the same time, the system reads the yaw displacement parameters, mainly the yaw rate, in real time from the data structure associated with the vehicle status data, provided by the inertial measurement unit. By performing an algorithmic matrix multiplication of this parameter with the vehicle's geometric model and mass distribution parameters, the system further obtains vehicle yaw stability parameters that describe the tendency or amplitude of inertial tail-swing caused by uneven braking force or lateral force.

[0067] Among them, vehicle yaw stability parameters are a collective term for the vehicle's lateral dynamic indicators, which include yaw rate. lateral acceleration The equal-component state vector comprehensively reflects the vehicle's driving stability.

[0068] Subsequently, the control algorithm uses wheel slip ratio and vehicle yaw stability parameters as dual-condition input variables, namely the real-time slip ratio of each wheel. and yaw rate The system performs fitting calculations using a pre-established multidimensional lookup table or a real-time solved nonlinear dynamic model. The goal of the calculation is to find a safe braking pressure control strategy that fully utilizes the available adhesion between the tire and the ground while ensuring the vehicle does not experience excessive yaw or sideslip—this is the target braking pressure calculation model. In this embodiment, this strategy is also associated with the dynamic optimal brake curve curvature value, which is a geometrical representation of the target braking pressure calculation model. It characterizes the ideal rate of brake pressure increase at any given time; a large curvature indicates that the pressure can increase rapidly, while a small curvature indicates that a gradual increase is needed to prevent instability. The output of this equation is a time-varying sequence of target pressure values. .

[0069] The system uses a pulse width modulation (PWM) encoder to reconstruct and convert this continuously changing target pressure value sequence into a target control signal that carries the target PWM duty cycle in real time. The target PWM control signal is a series of alternating high and low level square waves. The ratio of the high-level duration within one cycle to the entire cycle is the duty cycle. By rapidly adjusting the duty cycle, linear analog-level control of the downstream actuator can be achieved. The duty cycle of this digital stream... With target pressure value A proportional or specific functional relationship is established to precisely control the hydraulic force ultimately applied to the brake in the next step.

[0070] For example, the control unit begins closed-loop regulation simultaneously with the formation of high-pressure brake fluid. Assume that at a certain instant... The system measures the vehicle's reference speed. The speed of the left front wheel is 20 m / s. The speed of the right front wheel is 17 m / s. The speed is 17.5 m / s. The system calculates the slip ratio of the left front wheel. Right front wheel slip ratio At the same time, the IMU reports the current yaw rate. The slip ratio is 0.2 rad / s, indicating a slight tendency for the vehicle to drift to the left. The system inputs these two slip ratios and yaw rates into the control algorithm. Based on the preset control law, the algorithm determines that: the current slip ratio of the left wheel is close to the optimal adhesion point, requiring cautious pressure increase; the right wheel still has some margin; and there is yaw that needs to be suppressed. After comprehensive judgment, the target braking pressure calculation model outputs the target braking pressures for the left and right wheels at this moment. and The PWM encoder then converts these two target pressure values ​​into two independent target PWM control signals. Assuming the PWM frequency is 2kHz and the duty cycle is linearly related to the pressure (0-100% corresponds to 0-20MPa), the duty cycles of the two generated PWM signals at that moment are respectively... and These two digital signals will be sent to the final pressure regulating valve of their respective wheels.

[0071] In one embodiment of the present invention, the pressure feedback modulation module is configured to perform the following steps: The target PWM control signal is continuously applied to both ends of the induction coil of the proportional control valve to control the valve core opening. The high-frequency orbital displacement of the valve core dynamically shears and adjusts the flow area of ​​the high-pressure brake fluid entering the fluid flow pipeline, filters out pressure peaks, and reshapes the output smooth target brake fluid pressure. The target brake fluid pressure is continuously applied to the brakes, and anti-lock slip correction is performed based on vehicle status data during the final frictional engagement process.

[0072] The system sends the target PWM control signal to the induction coil assembly of the two-stage high-frequency proportional control valve connected in series with each wheel brake. It should be noted that the two-stage high-frequency proportional control valve is an electro-hydraulic proportional valve capable of responding to high-frequency PWM signals; its response frequency must match the PWM signal frequency, typically within a certain range. The above measures are taken to ensure that the fluid regulation is smooth enough and to avoid pressure pulsations.

[0073] The digital signal stream drives the magnetic circuit strength within the induction coil assembly to pulsate at the same frequency, thereby inducing a non-steady, high-frequency start-stop jitter displacement change at the microscopic level in its electronically controlled spindle valve. A secondary high-frequency proportional control valve is installed in the hydraulic passage from the energy storage chamber to the brake piston cavity, its core function being to act as the final flow regulation gate. By inducing this microscopic non-steady start-stop jitter displacement change, the system causes the valve core to not remain stably between the two stroke endpoints, but rather to undergo high-frequency micro-vibrations near the equilibrium position. This mechanism achieves continuous adjustment of the flow area through the time-stroke integral effect of the vibration, thereby intercepting and shearing the high-pressure brake fluid pouring from the pipeline with extremely high speed and precision.

[0074] Specifically, when the duty cycle of the target PWM control signal is high, the valve core opening time is longer than the closing time, allowing more high-pressure fluid to pass through; conversely, when the duty cycle is low, the opposite is true. In this way, the regulating valve dynamically adjusts the flow of hydraulic oil in each PWM cycle by smoothing out peaks and filling valleys according to the frequency and duty cycle changes of the pulse signal, thus performing a fine and smooth reduction of the overall fluid pressure.

[0075] The regulating valve outputs a target brake fluid pressure that has undergone smoothing, reduction, and reshaping. This target brake fluid pressure is the final hydraulic flow that directly acts on the brake. Its nonlinear correction is reflected in the fact that its pressure increase and change are not nonlinear, but rather the result of complex nonlinear adjustments based on the vehicle's real-time dynamics. The pressure curve of this thrust flow precisely matches the target brake pressure calculation model calculated in the previous steps. This precisely modulated fluid flow is ultimately injected into and compensated for in the brake chamber of the brake. The brake is the rotating component in the wet brake assembly that ultimately contacts the friction pads and generates braking torque. Under hydraulic action, the piston squeezes the friction pads to generate the final braking torque.

[0076] The entire process is a closed-loop feedback system. The system continuously monitors the wheel slip ratio and vehicle attitude, and performs anti-lock slip correction, so that the braking pressure always hovers dynamically at the edge of the limit grip margin. Ultimately, under the target criterion of maintaining the vehicle's center of gravity from overturning, this target criterion is a combination of multiple safety constraints, including but not limited to the wheel slip ratio not exceeding the threshold, the vehicle's yaw rate and roll angle being within the stable domain, and the braking deceleration not exceeding the structural bearing limit. This achieves a system-level pressure balance stabilization and control action. It should be understood that the pressure balance stabilization and control action refers to the final stable braking state of the vehicle. At this time, the braking force of each wheel, the ground adhesion force, and the vehicle's inertial force reach a dynamic balance, and the vehicle stops smoothly without sideslip or rotation, thus achieving a smooth and efficient anti-lock emergency braking stop.

[0077] For example, a target PWM control signal with a duty cycle of 31% for the left front wheel is sent to its corresponding secondary high-frequency proportional control valve. The valve spool of this control valve undergoes high-speed jitter displacement driven by the high-frequency PWM signal. Within one PWM cycle, its opening time accounts for 31%, and its closing time accounts for 69%. Through this rapid switching action, it controls the incoming... The high-pressure brake fluid is modulated to achieve an average output pressure of 6.2 MPa. This target brake fluid pressure of 6.2 MPa is injected into the brake chamber of the left front wheel, acting on the brake disc and friction pads to generate braking force precisely matched to the current wheel grip limit, stabilizing its slip ratio at around 15%. See [link to relevant documentation]. Figure 4 Similarly, the regulating valve on the right front wheel outputs a 6.8MPa fluid flow based on a 34% duty cycle. In each subsequent millisecond-level time step, the control system repeats this sensing-calculation-control cycle, continuously adjusting the PWM duty cycle to ensure the braking force applied to each wheel is always dynamically optimal. Ultimately, the vehicle comes to a safe and smooth stop with maximum deceleration without any wheel lock-up or loss of control.

[0078] In one embodiment of the present invention, after the aforementioned anti-lock braking emergency braking is completed and the vehicle is in a stable, pressure-balanced stopped state, the system will perform adaptive calibration correction. During this stage, sensors are responsible for collecting residual pressure information in the pipeline and the brake piston reset stroke coordinates transmitted from the end caliper. Then, the electronic control unit compares the current residual pressure information with discrete data showing a deviation from the reset stroke coordinates, and stores this discrete data as a residual pressure correction baseline in the internal memory of the system control unit. This data is used for subsequent adaptive learning corrections to dynamically compensate for mechanical wear and spring fatigue aging, ensuring long-term response accuracy and reliability.

[0079] Each of the modules can be implemented in whole or in part through software, hardware, or a combination thereof. It supports hardware embedded in or independent of the processor in the computer device, and also supports software stored in the memory of the computer device, so that the processor can call and execute the operations corresponding to each of the above modules.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. An emergency braking control system based on a wet brake reversal hydraulic circuit, characterized in that, include: The monitoring architecture generation module is used to obtain backup control fluid with preset pressure from the return pipeline and to obtain vehicle status data including the main brake oil circuit pressure in real time. The failure state switching module is used to monitor the main brake oil circuit pressure. When it is determined that a main brake system pressure loss fault has occurred, it uses the pressure difference formed between the main brake oil circuit after pressure loss and the backup control oil to drive the pressure difference reversing valve to switch and release the backup control oil as pilot pressure oil. The brake clearance pre-filling module is used to guide pilot pressure oil into the brake actuator to push the internal brake piston to eliminate mechanical clearance; at the same time, it diverts part of the pilot pressure oil to the control end of the lock-up valve, so that the lock-up valve remains physically closed and ready to be activated. The fault fingerprint verification module is used to extract the pressure drop characteristic data when a fault occurs, match and verify it with the built-in fault feature library, and generate an electronic control trigger signal after the verification is successful. The high-pressure source unlocking module is used to pressurize the local oil in the control terminal of the lock valve according to the electronic control trigger signal to open the lock valve and release the high-pressure brake fluid accumulated in the high-pressure accumulator. The braking strategy generation module is used to calculate the target braking pressure curve based on vehicle status data and generate a target control signal that matches the curve. The pressure feedback modulation module is used to send the target control signal to the regulating valve to dynamically adjust the flow and pressure of the high-pressure brake fluid and output the target brake fluid pressure to the brake to complete emergency braking.

2. An emergency braking control system based on a wet brake reversal hydraulic circuit according to claim 1, characterized in that, The monitoring architecture generation module is configured to perform the following steps: By obtaining reflux liquid through a pressure-stabilizing and flow-controlling element integrated into the reflux pipeline bypass, a standby control oil with a constant pressure base value is prepared. The backup control fluid and the main brake fluid pressure are applied to the two ends of the differential pressure directional valve core respectively. Under normal operating conditions, the high pressure of the main brake fluid circuit locks the valve core in the position that isolates the backup channel. The vehicle attitude yaw matrix of the current timestamp node is obtained in parallel and packaged with the main brake oil pressure to generate timestamped vehicle state data.

3. An emergency braking control system based on a wet brake reversal hydraulic circuit according to claim 1, characterized in that, The failure state switching module is configured to perform the following steps: Capture the descent gradient value and frequency domain distortion parameter characteristics of the main brake oil circuit pressure in the vehicle status data. When the descent gradient value exceeds the preset failure judgment threshold and the high frequency component in the frequency domain exceeds the limit, verify that the main brake system pressure loss fault has occurred. After a pressure loss fault occurs, the residual pressure force on the valve core end face caused by the main brake oil circuit pressure drops sharply. When the residual pressure force is less than the resultant force of the opposing backup control oil pressure and the return spring thrust, the valve core of the driving differential pressure reversing valve moves to the reverse position. After the valve core moves to the reverse position, it cuts off the main brake oil circuit and connects the backup channel, releasing the backup control oil to form pilot pressure oil for directional delivery.

4. An emergency braking control system based on a wet brake reversal hydraulic circuit according to claim 1, characterized in that, The brake clearance pre-filling module is configured to perform the following steps: The pilot pressure oil is guided into the piston end chamber of the brake actuator; The pressure of the pilot oil is used to push the brake piston forward, fill the inherent mechanical gap between the friction components, and generate a pre-braking contact force to eliminate braking shock. A portion of the pilot pressure oil is separated and allowed to enter the pilot control chamber of the lock-up valve. Since the pressure value of the pilot pressure oil is lower than the opening threshold of the built-in spring of the lock-up valve, the valve core remains blocked and in a standby state.

5. An emergency braking control system based on a wet brake reversal hydraulic circuit according to claim 4, characterized in that, After the step of generating the pre-braking clamping force, the following steps are also included: The sensor collects data on the volume displacement generated by the brake piston when filling the inherent mechanical gap, as well as the back pressure data when the friction assembly returns. A brake soft-fit correlation stiffness model is constructed by integrating volume displacement data and back pressure data, and then updated to the vehicle state data for underlying benchmark refresh.

6. An emergency braking control system based on a wet brake reversal hydraulic circuit according to claim 1, characterized in that, The fault fingerprint verification module is configured to perform the following steps: By using a bandpass filter to filter out the low-pressure fluctuation signal caused by turbulence in the pressure drop characteristic data, the feature vector of the pressure decay curve is extracted. Substitute the feature vector into the preset algorithm model, and compare it with the built-in fault feature library of pipeline rupture modes using the weighted Euclidean distance. When the distance is less than the preset matching threshold, set an authorized trigger flag. Based on the trigger flag and the built-in exception compensation mapping, an electronically controlled trigger signal with a specific pulse width and voltage amplitude is compiled and generated.

7. An emergency braking control system based on a wet brake reversal hydraulic circuit according to claim 1, characterized in that, The high-voltage source unlocking module is configured to perform the following steps: The electronically controlled trigger signal is fed into the booster solenoid valve to excite the winding and drive the electromagnetic moving iron core to close the oil drain channel and act as a booster plunger to push into the blind path chamber. After the drain channel is closed, the pilot pressure oil remaining in the front blind path is compressed by the volume of the electromagnetic moving iron core, which induces local electromagnetic work to increase the pressure, and obtains a local over-limit hydraulic pressure that is greater than the opening threshold of the built-in spring of the lock valve. By utilizing local over-limit hydraulic pressure to overcome spring resistance, the valve core of the lock-up valve is forced to complete the opening operation, opening the outlet of the energy storage chamber and thus releasing the high-pressure brake fluid.

8. An emergency braking control system based on a wet brake reversal hydraulic circuit according to claim 1, characterized in that, The braking strategy generation module is configured to perform the following steps: The dynamic linear velocity slip ratio of each wheel is calculated based on the wheel speed sensor data, and is used as the wheel slip ratio. By extracting yaw rate and lateral acceleration from vehicle state data, vehicle yaw stability parameters that measure the magnitude of vehicle sideslip drift are separated through matrix calculation. By combining wheel slip ratio and vehicle yaw stability parameters, multi-condition nonlinear constraint fitting calculations are performed to solve the target braking pressure curve that prevents wheel lock-up and vehicle instability, and then converted into the corresponding target control signal through pulse width modulation coding.

9. An emergency braking control system based on a wet brake reversal hydraulic circuit according to claim 1, characterized in that, The regulating valve is a proportional regulating valve connected in series in the high-pressure oil circuit, the target control signal is the target PWM control signal, and the pressure feedback modulation module is configured to perform the following steps: The target PWM control signal is continuously applied to both ends of the induction coil of the proportional control valve to control the valve core opening. The high-frequency orbital displacement of the valve core dynamically shears and adjusts the flow area of ​​the high-pressure brake fluid entering the fluid flow pipeline, filters out pressure peaks, and reshapes the output smooth target brake fluid pressure. The target brake oil pressure is continuously applied to the brake, and anti-lock slip correction is performed based on vehicle status data during the final friction locking interference process.

10. An emergency braking control system based on a wet brake reversal hydraulic circuit according to claim 9, characterized in that, After completing emergency braking, the following steps are included: Collect residual pressure information in the pipeline during the pressure balance and stable shutdown phase, as well as the brake piston reset stroke coordinates transmitted from the end caliper; The current residual pressure information is compared with the discrete data that has deviated from the reset stroke coordinate. This discrete data is stored as the residual pressure correction baseline and used to compensate for the initial pressure threshold of the next emergency braking control command.

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