Brake-by-wire smooth transition control method and system

Abstract

The invention provides a brake-by-wire smooth transition control method and system. A brake-by-wire smooth transition control method comprises the following steps that the working mode of a brake system is judged based on state information of the brake system; when the system is not normally powered on or has a fault, a mechanical backup mode is selected; when the system is normally powered on, has no fault and is not in a pedal stepping-down power-on state, a normal drive-by-wire mode is selected; when the system is normally powered on, has no fault and is in a pedal stepping power-on state, a working mode of the braking system is selected based on a comparison result of the manual cylinder pressure and a first preset pressure threshold value; wherein when the manual cylinder pressure is larger than a first preset pressure threshold value, a special power-on mode is selected, and when the manual cylinder pressure is not larger than the first preset pressure threshold value, a normal drive-by-wire mode is selected; and the state of the valve group in the hydraulic loop is controlled to realize smooth transition control of the braking system. The driving experience is improved, and the safety is improved.

Description

Technical Field

[0001] The present invention relates to a wire control braking control method and system, and particularly to a wire control braking smooth transition control method and system, belonging to the technical field of wire control braking. Background Art

[0002] With the development of automotive electronic technology, wire control braking systems have gradually become an important configuration for modern vehicles. The fully decoupled wire control braking system can achieve more flexible braking control by completely separating the pedal input from the execution circuit, providing necessary underlying support for advanced driver assistance systems and autonomous driving technologies. However, during the system mode switching process (especially in scenarios such as power-on switching and fault switching), when stepping on the pedal to power on, the sudden sinking of the pedal due to the braking hydraulic balance problem seriously affects the driver experience; the braking force is discontinuous during the switching between different braking modes, which may lead to sudden changes in the braking effect; the uncertainty of system parameters increases during mode switching, making it difficult to ensure control accuracy; the safety guarantee problem during the coordination of the electronic parking brake and the service braking system; these problems not only affect driving comfort but may also pose safety risks in specific scenarios (such as hill start). Summary of the Invention

[0003] Based on the above background, the purpose of the present invention is to provide a wire control braking smooth transition control method to achieve smooth transition between various modes of the fully decoupled wire control braking system, improve the driving experience and enhance safety.

[0004] Another object of the present invention is to provide a wire control braking smooth transition control system.

[0005] To achieve the above object of the invention, the present invention provides the following technical solutions:

[0006] A wire control braking smooth transition control method, the method comprising the following steps:

[0007] Obtain braking system state information, where the braking system state information includes system power state, system fault state, brake pedal operation state, and master cylinder pressure state;

[0008] Based on the braking system state information, judge the working mode of the braking system, where the braking system working mode includes normal wire control mode, special power-on mode, and mechanical backup mode;

[0009] When the system is not powered on normally or there is a fault, select the mechanical backup mode;

[0010] When the system is powered on normally, there is no fault, and it is not in the state of stepping on the pedal to power on, select the normal wire control mode;

[0011] When the system is powered on normally, there is no fault, and it is in the power-on state with the pedal depressed, select the braking system operating mode based on the comparison result between the master cylinder pressure and the first preset pressure threshold; among them, when the master cylinder pressure is greater than the first preset pressure threshold, select the special power-on mode, and when the master cylinder pressure is not greater than the first preset pressure threshold, select the normal by-wire mode;

[0012] Based on the selected braking system operating mode, control the state of the valve group in the hydraulic circuit to achieve smooth transition control of the braking system.

[0013] Preferably, the control steps in the normal by-wire mode include:

[0014] Control the isolation valve corresponding to the master cylinder hydraulic circuit to change to the closed state;

[0015] Control the isolation valves corresponding to the simulator cylinder hydraulic circuit and the servo cylinder hydraulic circuit to change to the open state;

[0016] Establish the mapping relationship between the brake pedal stroke and the target braking pressure;

[0017] Control the servo actuator to output the braking force corresponding to the target braking pressure.

[0018] Preferably, the control steps in the special power-on mode include:

[0019] Keep the isolation valve corresponding to the simulator cylinder hydraulic circuit in the closed state;

[0020] Control the isolation valve corresponding to the master cylinder hydraulic circuit to change to the closed state;

[0021] Generate a dual-source target pressure value, which includes a first target pressure value generated based on the brake pedal stroke information and a second target pressure value generated based on the master cylinder pressure information;

[0022] Select the larger of the first target pressure value and the second target pressure value as the final target braking pressure;

[0023] Control the servo actuator to output the braking force corresponding to the final target braking pressure.

[0024] Preferably, the control steps in the mechanical backup mode include:

[0025] Keep the isolation valve corresponding to the master cylinder hydraulic circuit in the open state;

[0026] Keep the isolation valves corresponding to the simulator cylinder hydraulic circuit and the servo cylinder hydraulic circuit in the closed state;

[0027] Connect the master cylinder and the wheel cylinder hydraulic circuit directly.

[0028] Preferably, the wire-controlled braking smooth transition control method further includes the following steps:

[0029] Under the special power-on mode, monitor the change of the master cylinder pressure;

[0030] When the master cylinder pressure drops below the second preset pressure threshold, switch the braking system from the special power-on mode to the normal wire-controlled mode;

[0031] Wherein, the second preset pressure threshold is less than the first preset pressure threshold.

[0032] Preferably, the wire-controlled braking smooth transition control method further includes the following steps:

[0033] Perform validity detection on signals of multiple pressure sensors including the master cylinder pressure sensor and the electronic stability control system pressure sensor;

[0034] When the signal of the master cylinder pressure sensor is invalid, the system enters the mechanical backup mode;

[0035] When the signal of the electronic stability control system pressure sensor is invalid, set its measured value to zero;

[0036] When the signals of both pressure sensors are valid, compare and analyze the measured values of the two pressure sensors;

[0037] When the difference between the measured values of the two pressure sensors exceeds the preset difference threshold and the measured value of the master cylinder pressure sensor is less than the measured value of the electronic stability control system pressure sensor, the system enters the mechanical backup mode.

[0038] Preferably, the wire-controlled braking smooth transition control method further includes the following steps:

[0039] Monitor the state of the electronic parking brake system and its historical state changes;

[0040] When the electronic parking brake system is in the pulled-up state and its state has not changed after power-on, the system enters the mechanical backup mode;

[0041] When the electronic parking brake system is in the released state or its state has changed, judge the system working mode according to other state information.

[0042] Preferably, the wire-controlled braking smooth transition control method further includes the following steps:

[0043] Under the special power-on mode, monitor the vehicle motion state parameters in real time;

[0044] When it is detected that the vehicle has a tendency to roll backward, gradually increase the target braking pressure according to a preset increment;

[0045] After the vehicle rollback state is eliminated, if the increased target braking pressure exceeds the maximum pressure limit value before the vehicle rollback, the target braking pressure is gradually reduced to within this limit value in accordance with a preset decrement.

[0046] When the master cylinder pressure meets the conditions, smoothly transition from the special power-on mode to the normal by-wire mode.

[0047] A by-wire braking smooth transition control system, comprising:

[0048] A state monitoring module for obtaining braking system state information, where the braking system state information includes system power state, system fault state, brake pedal operation state, and master cylinder pressure state;

[0049] A mode determination module for determining the braking system operating mode based on the braking system state information, where the braking system operating mode includes a normal by-wire mode, a special power-on mode, and a mechanical backup mode;

[0050] A transition control module for controlling the state of the valve group in the hydraulic circuit based on the selected braking system operating mode to achieve smooth transition control between different modes of the braking system;

[0051] A target pressure generation module for generating a final target braking pressure based on brake pedal stroke information and master cylinder pressure information in the special power-on mode;

[0052] A vehicle rollback protection module for monitoring the vehicle motion state and dynamically adjusting the target braking pressure when a vehicle rollback trend is detected in the special power-on mode.

[0053] Preferably, the by-wire braking smooth transition control system further includes:

[0054] A hydraulic regulation module, where the hydraulic regulation module includes a master cylinder, an analog cylinder, a servo cylinder, and corresponding isolation valve groups;

[0055] A sensor module, where the sensor module includes a stroke sensor for detecting the brake pedal stroke and a pressure sensor for detecting the master cylinder pressure;

[0056] An execution control module, where the execution control module includes a servo motor for driving the servo cylinder and its transmission system.

[0057] Compared with the prior art, the present invention has the following advantages:

[0058] A wire-controlled braking smooth transition control method and system of the present invention achieve smooth and imperceptible transition between different braking modes on the premise of ensuring braking safety, effectively solve the problem of pedal sinking when stepping on the pedal to power on, and at the same time take into account the safety guarantee requirements in special scenarios, improving the performance and user experience of the fully decoupled wire-controlled braking system. Description of the Drawings

[0059] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to the provided drawings.

[0060] Figure 1 It is a schematic structural diagram of a fully decoupled wire-controlled braking system in an embodiment of the present invention;

[0061] Figure 2 It is a schematic flow diagram of the wire-controlled braking smooth transition control method of the present invention;

[0062] In the figure: 1. Braking pedal; 2. Mechanical push rod; 3. Stroke sensor; 4. Liquid storage tank; 5. Master cylinder; 6. Master cylinder pressure sensor; 7. Master cylinder circuit isolation valve; 8. Simulated cylinder circuit isolation valve; 9. Simulated cylinder; 10. Servo cylinder circuit isolation valve; 11. Servo cylinder pressure sensor; 12. Servo cylinder block; 13. Servo cylinder piston; 14. Ball screw drive mechanism; 15. Servo motor. Detailed Embodiments

[0063] The following will further specifically illustrate the technical solutions of the present invention through specific embodiments in combination with the drawings. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any formal modification and / or change made to the present invention will fall within the protection scope of the present invention.

[0064] In the present invention, unless otherwise specified, all parts and percentages are in weight units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments are conventional methods in the art unless otherwise specified. The components or equipment in the following embodiments are general standard parts or components known to those skilled in the art unless otherwise specified, and their structures and principles can all be known by those skilled in the art through technical manuals or through conventional experimental methods.

[0065] The following will make a detailed description of the embodiments of the present invention in conjunction with the accompanying drawings. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, one or more embodiments can also be implemented by those skilled in the art without these specific details.

[0066] An embodiment of the present invention discloses a method for smooth transition control of a wire-controlled brake, which is applied to a fully decoupled wire-controlled brake system as Figure 1 shown. The fully decoupled wire-controlled brake system includes a brake pedal 1, a mechanical push rod 2, a stroke sensor 3, a liquid storage tank 4, a master cylinder 5 (including a first piston, a second piston and corresponding springs), a master cylinder pressure sensor 6, a master cylinder circuit isolation valve 7, a simulation cylinder circuit isolation valve 8, a simulation cylinder 9, a servo cylinder circuit isolation valve 10, a servo cylinder pressure sensor 11, a servo cylinder block 12, a servo cylinder piston 13, a ball screw drive mechanism 14 and a servo motor 15. Among them, the master cylinder circuit isolation valve 7 is a normally open valve, and the simulation cylinder circuit isolation valve 8 and the servo cylinder circuit isolation valve 10 are both normally closed valves.

[0067] The method for smooth transition control of the wire-controlled brake includes the following steps:

[0068] Obtain the braking system status information, which includes the system power status, the system fault status, the brake pedal operation status and the master cylinder pressure status;

[0069] Based on the braking system status information, judge the working mode of the braking system, and the working mode of the braking system includes a normal wire control mode, a special power-on mode and a mechanical backup mode;

[0070] When the system is not powered on normally or there is a fault, select the mechanical backup mode;

[0071] When the system is powered on normally, there is no fault and it is not in the pedal-pressed power-on state, select the normal wire control mode;

[0072] When the system is powered on normally, there is no fault and it is in the pedal-pressed power-on state, select the working mode of the braking system based on the comparison result between the master cylinder pressure and the first preset pressure threshold; wherein, when the master cylinder pressure is greater than the first preset pressure threshold, select the special power-on mode, and when the master cylinder pressure is not greater than the first preset pressure threshold, select the normal wire control mode;

[0073] Based on the selected working mode of the braking system, control the state of the valve group in the hydraulic circuit to achieve smooth transition control of the braking system.

[0074] As Figure 2 shown, the method for smooth transition control of the wire-controlled brake specifically includes the following steps.

[0075] Step S100: Detect whether the by - wire braking system is powered on normally.

[0076] If the by - wire braking system is not powered on normally, execute step S110; if the by - wire braking system is powered on normally, execute step S120.

[0077] Step S110: Enter the mechanical backup braking mode.

[0078] In the mechanical backup braking mode, control the manual cylinder circuit isolation valve 7 to remain open, and control the simulation cylinder circuit isolation valve 8 and the servo cylinder circuit isolation valve 10 to remain closed. At this time, when the brake pedal 1 is depressed, the mechanical push rod 2 is pushed to move leftward at the same time, and the piston in the manual cylinder 5 moves leftward, and the brake fluid in the two piston chambers of the manual cylinder is hermetically compressed. Since the manual cylinder circuit isolation valve 7 is in the open state, the braking circuits from the two piston chambers of the manual cylinder 5 to the electronic stability control system (ESC) and the wheel ends are connected. When the brake pedal 1 is depressed to build pressure, the pressure in the connected braking circuits is normally established, and the pressure is greater than 0, while the pressure in the circuit after the simulation cylinder circuit isolation valve 8 to the simulation cylinder 9 is 0, and the pressure before the servo cylinder circuit isolation valve 10 and in the servo cylinder is also 0.

[0079] Step S120: Detect whether there is a fault in the by - wire braking system.

[0080] In this embodiment, by detecting whether there are faults in the servo motor 15, the manual cylinder circuit isolation valve 7, and the servo cylinder circuit isolation valve 10, it is determined whether there is a fault in the by - wire braking system. If there are no faults in the servo motor 15, the manual cylinder circuit isolation valve 7, and the servo cylinder circuit isolation valve 10, it is determined that there is no fault in the by - wire braking system; if there is at least one fault in the servo motor 15, the manual cylinder circuit isolation valve 7, and the servo cylinder circuit isolation valve 10, it is determined that there is a fault in the by - wire braking system.

[0081] If there is a fault in the by - wire braking system, execute step S110; if there is no fault in the by - wire braking system, execute step S130.

[0082] Step S130: Detect whether the by - wire braking system is in the brake - pedal - powered - on state.

[0083] The brake - pedal - powered - on state means that at the moment of power - on, it is detected that the brake pedal 1 is in the depressed state, that is, at the moment of power - on, the controller recognizes that the brake pedal 1 is depressed. And as long as it is recognized as the brake - pedal - powered - on state at the moment of power - on of the by - wire braking system, if the exit condition is not met all the time, the system is still considered to be in the brake - pedal - powered - on state. When the by - wire braking system is in the brake - pedal - powered - on state, the brake - pedal - powered - on state is exited only when it is detected that the brake pedal is fully released.

[0084] If the wire control braking system is not in the power-on state by stepping on the pedal, step S140 is executed; if the wire control braking system is in the power-on state by stepping on the pedal, step S150 is executed.

[0085] Step S140: Enter the normal wire control braking mode.

[0086] After entering the normal wire control braking mode, all solenoid valves are energized and actuated, that is, the manual cylinder circuit isolation valve 7 is controlled to change from the open state to the closed state, and the simulation cylinder circuit isolation valve 8 and the servo cylinder circuit isolation valve 10 are controlled to change from the closed state to the open state. The pressures in the manual cylinder 5 and the simulation cylinder 9 can be measured by the manual cylinder pressure sensor 6, and the pressures in the servo cylinder block 12, the hydraulic circuits before and after the servo cylinder circuit isolation valve 10, the electronic stability control system, and the wheel ends can be measured by the servo cylinder pressure sensor 11.

[0087] Step S150: Determine whether the pressure in the manual cylinder at the moment of power-on is greater than the first pressure threshold.

[0088] There is a relationship between the pressure in the manual cylinder at the moment of stepping on the pedal to power on and the changes in the pedal force, the mechanical push rod stroke, the manual cylinder pressure, and the mechanical push rod stroke. When stepping on the pedal to power on, the greater the pressure in the manual cylinder, the more obvious the pedal sinks. In this embodiment, the first pressure threshold is set as P1. When the pressure in the manual cylinder is greater than P1, a significant pedal sinking feeling will occur when the simulation cylinder is balanced, and special measures need to be taken.

[0089] If the pressure in the manual cylinder is less than or equal to the first pressure threshold, step S140 is executed; if the pressure in the manual cylinder is greater than the first pressure threshold, step S160 is executed.

[0090] Step S160: Enter the braking mode of stepping on the pedal to power on.

[0091] In the braking mode of stepping on the pedal to power on, the simulation cylinder circuit isolation valve 8 is controlled to remain in the closed state, and the manual cylinder circuit isolation valve 7 is controlled to change from the open state to the closed state after being energized. In this way, the brake fluid in the manual cylinder 5 to the circuits after the simulation cylinder circuit isolation valve 8 and after the manual cylinder circuit isolation valve 7 will be blocked, thereby avoiding the sudden sinking of the pedal when stepping on the brake pedal deeply to power on.

[0092] Step S170: Determine the target braking pressure and control the braking output.

[0093] In the braking mode of stepping on the pedal to power on, the following operations are performed:

[0094] Determine the first target braking pressure according to the stroke of the mechanical push rod 2;

[0095] Determine the second target braking pressure according to the pressure detected by the manual cylinder pressure sensor 6;

[0096] Select the larger value between the first target braking pressure and the second target braking pressure as the target braking pressure;

[0097] Based on the target braking pressure, control the servo motor 15 to output the corresponding braking force.

[0098] Although the closing of the master cylinder circuit isolation valve 7 and the simulation cylinder circuit isolation valve 8 will cause the brake pedal 1 to no longer be depressed, but at this time if the driver continues to increase the force of depressing the brake pedal 1, the measured value of the master cylinder pressure sensor 6 will further increase. Taking this increase in value as the control basis, increase the target pressure of the braking system to generate a greater braking pressure at the wheel ends to meet the braking requirements.

[0099] Step S180: In the on - pedal electric braking mode, detect the pressure in the master cylinder. If the pressure in the master cylinder is less than the second pressure threshold, enter the normal line control braking mode, where the first pressure threshold is greater than the second pressure threshold.

[0100] In this embodiment, set the second pressure threshold as P2, which is less than the first pressure threshold P1. This design avoids the system from frequently switching modes near the threshold by introducing a hysteresis characteristic. When the driver slightly releases the brake pedal 1 and the pressure in the master cylinder drops below P2, the system will switch from the on - pedal electric braking mode to the normal line control braking mode.

[0101] Step S190: In the on - pedal electric braking mode, detect whether vehicle creep occurs.

[0102] In this embodiment, by monitoring the vehicle speed, acceleration, and slope information, determine whether vehicle creep occurs. If it is detected that vehicle creep occurs, the system will increase the target braking pressure according to the set increase gradient based on the creep state, where the increased target braking pressure is not greater than the maximum allowable working pressure of the line control braking system.

[0103] After detecting the stop of vehicle creep, if the increased target braking pressure is greater than the maximum braking pressure limit value in the vehicle stationary state before creep, then decrease the increased target braking pressure to the maximum braking pressure limit value according to the set decrease gradient, and enter the normal line control braking mode when the pressure in the master cylinder is less than the second pressure threshold.

[0104] Step S200: Detect whether the line control braking system is powered off.

[0105] If it is detected that the line control braking system is not powered off, return to step S120; if it is detected that the line control braking system is powered off, the process ends.

[0106] This embodiment further provides a signal verification mechanism in the pedal - depressed power - on state. Before determining whether the pressure in the master cylinder is greater than the first pressure threshold at the moment of power - on, the method further includes the following steps:

[0107] If the electronic brake - by - wire system is in the pedal - depressed power - on state, signal verification is performed on the pressure sensor of the electronic stability control system itself to determine whether the first pressure measurement value is valid; signal verification is performed on the master cylinder pressure sensor to determine whether the second pressure measurement value is valid.

[0108] If the first pressure measurement value is invalid, the first pressure measurement value is set to 0; if the second pressure measurement value is invalid, the mechanical backup braking mode is entered.

[0109] If both the first pressure measurement value and the second pressure measurement value are valid, by comparing the first pressure measurement value and the second pressure measurement value, it is determined whether there is an abnormality in the pressure within the electronic brake - by - wire system:

[0110] If the absolute value of the difference between the first pressure measurement value and the second pressure measurement value is less than or equal to the pressure difference threshold, it is determined that there is no abnormality in the pressure within the electronic brake - by - wire system;

[0111] If the difference between the first pressure measurement value and the second pressure measurement value is greater than the pressure difference threshold, it is determined that there is an abnormality in the pressure within the electronic brake - by - wire system;

[0112] If the difference between the second pressure measurement value and the first pressure measurement value is greater than the pressure difference threshold, it is determined that there is no abnormality in the pressure within the electronic brake - by - wire system.

[0113] If there is no abnormality in the pressure within the electronic brake - by - wire system, the step of determining whether the pressure in the master cylinder is greater than the first pressure threshold at the moment of power - on is executed; if there is an abnormality in the pressure within the electronic brake - by - wire system, the mechanical backup braking mode is entered.

[0114] This embodiment further provides a control strategy considering the state of the electronic parking brake system. Before detecting whether the electronic brake - by - wire system is in the pedal - depressed power - on state, the method further includes the following steps:

[0115] In the case where the vehicle is equipped with an electronic parking brake system, it is detected whether the electronic parking brake system is in the pulled - up state and whether the state of the electronic parking brake system has not changed after power - on.

[0116] If the electronic parking brake system is in the non - pulled - up state, or the electronic parking brake system is in the pulled - up state and its state has changed, the step of detecting whether the electronic brake - by - wire system is in the pedal - depressed power - on state is executed.

[0117] If the electronic parking brake system is in the pulled-up state and its state has never switched, enter the mechanical backup braking mode.

[0118] For a vehicle equipped with an electronic parking brake system, when the vehicle is powered on with the brake pedal depressed, if the electronic parking brake system is in the pulled-up state and its state has never switched, the logic of the mechanical backup braking mode can be maintained. In this way, the problem of sudden pedal sinking can be avoided, and the vehicle rollback caused by insufficient braking pressure that may occur can be avoided.

[0119] This method selects the mode based on the judgment of the master cylinder pressure threshold, making full use of the characteristics of the hydraulic system. When the master cylinder pressure exceeds the first pressure threshold, by keeping the isolation valve of the simulation cylinder circuit closed and closing the isolation valve of the master cylinder circuit, the hydraulic flow path between the master cylinder and the simulation cylinder is effectively blocked, fundamentally avoiding the pedal sinking phenomenon during the hydraulic balance process. Secondly, by introducing a dual-target pressure generation mechanism (based on the mechanical push rod stroke and the master cylinder pressure) and adopting the maximum value strategy, it is ensured that sufficient braking force can be provided in any case to guarantee driving safety. In addition, different pressure thresholds are designed for mode entry and exit judgment (the first pressure threshold is greater than the second pressure threshold), and the hysteresis characteristic is cleverly utilized to prevent the system from frequently switching modes near the threshold.

[0120] The following remarkable effects are achieved by the method provided in the present invention. The pedal sinking phenomenon when the pedal is depressed to power on is effectively eliminated, making the operation feeling of the brake pedal more natural and coherent, and greatly improving the driver experience. For special working conditions such as hill start, through the vehicle rollback detection and anti-rollback control strategy, the system can intelligently increase the braking pressure to cope with the vehicle rollback risk and smoothly reduce the pressure after the risk is eliminated, ensuring both safety and a good driving experience. Through measures such as multi-sensor signal verification, abnormal judgment mechanism, and the status check of the electronic parking brake system, the system can handle various abnormal situations and timely switch to a safe backup mode, effectively preventing braking risks caused by sensor abnormalities, system failures, etc.

[0121] An embodiment of the present invention also discloses a wire-controlled brake smooth transition control system, including:

[0122] A status monitoring module, configured to obtain the braking system status information, where the braking system status information includes the system power status, system fault status, brake pedal operation status, and master cylinder pressure status;

[0123] A mode judgment module, configured to judge the working mode of the braking system based on the braking system status information, where the working mode of the braking system includes a normal wire control mode, a special power-on mode, and a mechanical backup mode;

[0124] A transition control module, configured to control the state of a valve group in a hydraulic circuit based on the selected operating mode of the braking system to achieve smooth transition control between different modes of the braking system;

[0125] A target pressure generation module, configured to generate a final target braking pressure based on the brake pedal travel information and the master cylinder pressure information in a special power-on mode;

[0126] A rollback protection module, configured to monitor the vehicle motion state and dynamically adjust the target braking pressure when a rollback trend is detected in a special power-on mode;

[0127] A hydraulic regulation module, which includes a master cylinder, an analog cylinder, a servo cylinder, and corresponding isolation valve groups;

[0128] A sensor module, which includes a travel sensor for detecting the brake pedal travel and a pressure sensor for detecting the master cylinder pressure;

[0129] An execution control module, which includes a servo motor for driving the servo cylinder and its transmission system.

[0130] In this article, specific examples are used to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A wire control braking smooth transition control method, characterized in that: The method includes the following steps: Obtain the braking system status information, where the braking system status information includes the system power status, system fault status, brake pedal operation status, and master cylinder pressure status; Based on the braking system status information, determine the braking system working mode, where the braking system working mode includes the normal by-wire mode, special power-on mode, and mechanical backup mode; When the system fails to power on normally or there is a fault, select the mechanical backup mode; When the system powers on normally, there is no fault, and it is not in the pedal-depressed power-on state, select the normal by-wire mode; When the system powers on normally, there is no fault, and it is in the pedal-depressed power-on state, select the braking system working mode based on the comparison result between the master cylinder pressure and the first preset pressure threshold; where when the master cylinder pressure is greater than the first preset pressure threshold, select the special power-on mode, and when the master cylinder pressure is not greater than the first preset pressure threshold, select the normal by-wire mode; Based on the selected braking system working mode, control the valve group status in the hydraulic circuit to achieve smooth transition control of the braking system.

2. The smooth transition control method for a wire brake according to claim 1, characterized in that: The control steps in the normal by-wire mode include: Control the isolation valve corresponding to the master cylinder hydraulic circuit to change to the closed state; Control the isolation valves corresponding to the simulation cylinder hydraulic circuit and the servo cylinder hydraulic circuit to change to the open state; Establish a mapping relationship between the brake pedal stroke and the target braking pressure; Control the servo actuator to output the braking force corresponding to the target braking pressure.

3. A wire-controlled braking smooth transition control method according to claim 1, characterized in that: The control steps in the special power-on mode include: Keep the isolation valve corresponding to the simulation cylinder hydraulic circuit in the closed state; Control the isolation valve corresponding to the master cylinder hydraulic circuit to change to the closed state; Generate a dual-source target pressure value, where the dual-source target pressure value includes a first target pressure value generated based on the brake pedal stroke information and a second target pressure value generated based on the master cylinder pressure information; Select the larger of the first target pressure value and the second target pressure value as the final target braking pressure; Control the servo actuator to output the braking force corresponding to the final target braking pressure.

4. A wire brake smooth transition control method according to claim 1, characterized in that: The control steps in the mechanical backup mode include: Keep the isolation valve corresponding to the master cylinder hydraulic circuit in the open state; Keep the isolation valves corresponding to the simulation cylinder hydraulic circuit and the servo cylinder hydraulic circuit in the closed state; Directly connect the master cylinder and the wheel cylinder hydraulic circuit.

5. A wire-controlled braking smooth transition control method according to claim 1, characterized in that: The by-wire braking smooth transition control method further includes the following steps: In the special power-on mode, monitor the change in the master cylinder pressure; When the master cylinder pressure drops below the second preset pressure threshold, switch the braking system from the special power-on mode to the normal by-wire mode; Wherein, the second preset pressure threshold is less than the first preset pressure threshold.

6. A wire-controlled braking smooth transition control method according to claim 1, characterized in that: The by-wire braking smooth transition control method further includes the following steps: Perform validity detection on the signals of multiple pressure sensors including the master cylinder pressure sensor and the electronic stability control system pressure sensor; When the signal of the master cylinder pressure sensor is invalid, the system enters the mechanical backup mode; When the signal of the electronic stability control system pressure sensor is invalid, set its measured value to zero; When the signals of both pressure sensors are valid, compare and analyze the measured values of the two pressure sensors; When the difference between the measured values of the two pressure sensors exceeds a preset difference threshold and the measured value of the master cylinder pressure sensor is less than the measured value of the electronic stability control system pressure sensor, the system enters the mechanical backup mode.

7. A wire-controlled braking smooth transition control method according to claim 1, characterized in that: The electro-hydraulic braking smooth transition control method further includes the following steps: Monitor the state of the electronic parking brake system and its historical state changes; When the electronic parking brake system is in the pulled-up state and its state has not changed after power-on, the system enters the mechanical backup mode; When the electronic parking brake system is in the released state or its state has changed, judge the working mode of the system according to other state information.

8. A wire brake smooth transition control method according to claim 1, characterized in that: The electro-hydraulic braking smooth transition control method further includes the following steps: Under the special power-on mode, continuously monitor the vehicle motion state parameters; When it is detected that the vehicle has a tendency to roll back, gradually increase the target braking pressure in accordance with a preset increment; After the roll-back state is eliminated, if the increased target braking pressure exceeds the maximum pressure limit value before the roll-back, gradually decrease the target braking pressure in accordance with a preset decrement to within the limit value; When the master cylinder pressure meets the conditions, smoothly transition from the special power-on mode to the normal electro-hydraulic control mode.

9. A wire-controlled braking smooth transition control system adopting the wire-controlled braking smooth transition control method as described in any one of claims 1-8, characterized in that: The system includes: A state monitoring module for obtaining the braking system state information, where the braking system state information includes the system power state, system fault state, brake pedal operation state, and master cylinder pressure state; A mode judgment module for judging the working mode of the braking system based on the braking system state information, where the braking system working mode includes the normal electro-hydraulic control mode, special power-on mode, and mechanical backup mode; A transition control module for controlling the state of the valve group in the hydraulic circuit based on the selected braking system working mode to achieve smooth transition control between different modes of the braking system; A target pressure generation module for generating the final target braking pressure based on the brake pedal stroke information and master cylinder pressure information under the special power-on mode; A roll-back protection module for monitoring the vehicle motion state and dynamically adjusting the target braking pressure when a roll-back tendency is detected under the special power-on mode.

10. A wire-controlled braking smooth transition control system according to claim 9, characterized in that: The system further includes: A hydraulic regulation module, where the hydraulic regulation module includes a master cylinder, an analog cylinder, a servo cylinder, and corresponding isolation valve groups; A sensor module, where the sensor module includes a stroke sensor for detecting the brake pedal stroke and a pressure sensor for detecting the master cylinder pressure; An execution control module, where the execution control module includes a servo motor for driving the servo cylinder and its transmission system.

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