Fully decoupled brake-by-wire method and system

Abstract

The present application relates to a wire-controlled braking method and system, which is applied to the field of wire-controlled braking technology. The method includes: when the system is normally powered on, setting the motor homing completion mark to incomplete, detecting whether there is a fault, and if not, detecting whether it is in the pedal-powered state; if so, entering the pedal-powered braking mode; if not, detecting whether there is a braking request and whether the mechanical zero point has been detected; regardless of whether there is a braking request, if the detection is completed, entering the normal wire-controlled braking mode; if there is a braking request and the detection is not completed, entering the wire-controlled braking mode with incomplete homing, and interrupting the execution of the servo cylinder piston mechanical zero point detection. If there is no braking request and the detection is not completed, the servo cylinder piston mechanical zero point detection is executed, and when the detection is completed, the motor homing completion mark is set to completed. If the system is not powered off, returning to detect whether there is a fault; if powered off, ending. Prioritizing the output of braking force and successfully completing the power-on homing.

Description

Technical Field

[0001] The present application relates to the technical field of wire-controlled braking, and in particular to a fully decoupled wire-controlled braking method and system. Background Art

[0002] Vehicles equipped with a brake-by-wire system without an additional travel sensor must calculate the servo cylinder piston position based on the rotor angle. Therefore, mechanical zeroing (homing) of the servo cylinder piston position is required each time the brake-by-wire system is powered on. This ensures accurate implementation of functions such as soft limit protection based on the mechanical zero point.

[0003] In related art, when a brake-by-wire system is powered on, it performs zeroing directly. Even when the brake pedal is pressed, zeroing is performed before the corresponding brake-by-wire braking is performed. Alternatively, when the brake pedal is pressed, zeroing and motor control are not performed, and the mechanical backup braking mode is directly used. Zeroing is not performed until the brake pedal is released.

[0004] However, when brake pressure output is required at the moment of pedaling and powering on, there may be a situation where the change has not been completed. Normal brake-by-wire mode will not be entered until the change is completed, which will cause a delay in brake pressure output. In addition, when the brake pedal is pressed and the normal brake-by-wire mode is directly entered, the pedal may suddenly sink, which is a poor experience. The deeper the brake pedal is pressed, the more obvious it is. Alternatively, if the mechanical backup braking mode is always used during the power-on phase of the brake pedal, when the PV (pressure-volume) characteristics of the vehicle's brake system are poor, there may be a problem of insufficient brake pressure output, affecting vehicle safety. Summary of the Invention

[0005] In order to solve the above technical problems, the present application provides a fully decoupled wire-controlled braking method, system and storage medium.

[0006] According to a first aspect of the present application, a fully decoupled brake-by-wire method is provided, comprising:

[0007] Check whether the brake-by-wire system is powered on normally;

[0008] If the wire control brake system is not powered on normally, the system enters the mechanical backup brake mode;

[0009] If the brake-by-wire system is powered on normally, setting the motor homing completion flag to incomplete, and detecting whether the brake-by-wire system has a fault;

[0010] If there is a fault in the brake-by-wire system, a mechanical backup braking mode is entered;

[0011] If there is no fault in the brake-by-wire system, detecting whether the brake-by-wire system is in a pedal-on state;

[0012] If the brake-by-wire system is in a pedal-on power-up state, entering a pedal-on power-up braking mode;

[0013] In the pedal-powered braking mode, the analog cylinder circuit isolation valve is controlled to remain in a closed state, and the manual cylinder circuit isolation valve is controlled to change from an open state to a closed state after power is applied. A first target brake pressure is determined according to the stroke of the mechanical push rod; a second target brake pressure is determined according to the pressure detected by the manual cylinder pressure sensor, and the larger value of the first target brake pressure and the second target brake pressure is selected as the target brake pressure, and the brake pressure is output;

[0014] If the brake-by-wire system is not in a pedal-powered state, detecting whether there is a braking request;

[0015] If there is a braking request, judging whether the mechanical zero point of the servo cylinder piston has been detected according to the motor completion home mark;

[0016] If there is a braking request and the motor has completed the homing mark, it is determined that the mechanical zero point of the servo cylinder piston has been detected, the normal wire control braking mode is entered, and the braking request is responded to by outputting a braking pressure corresponding to the braking request;

[0017] If there is a braking request and the motor homing completion mark is incomplete, it is determined that the mechanical zero point detection of the servo cylinder piston is incomplete, the homing is not completed, the wire control braking mode is entered, the process of executing the mechanical zero point detection of the servo cylinder piston is interrupted, and the braking request is responded to, and the braking pressure corresponding to the braking request is output;

[0018] If there is no braking request, judging whether the mechanical zero point of the servo cylinder piston has been detected according to the motor completion homing mark;

[0019] If there is no braking request and the motor has completed the homing mark, it is determined that the mechanical zero point of the servo cylinder piston has been detected and the normal wire control braking mode is entered;

[0020] If there is no braking request and the motor homing completion mark is not completed, it is determined that the mechanical zero point detection of the servo cylinder piston is not completed, the process of the servo cylinder piston mechanical zero point detection is executed, and when the mechanical zero point detection of the servo cylinder piston is completed, the motor homing completion mark is set to completed;

[0021] detecting whether the brake-by-wire system is powered off;

[0022] If it is detected that the brake-by-wire system is not powered off, returning to the step of detecting whether the brake-by-wire system has a fault;

[0023] If it is detected that the brake-by-wire system is powered off, the process ends.

[0024] Optionally, the method further includes:

[0025] During the process of pushing the servo cylinder piston forward to build pressure, if the servo cylinder piston is pushed to the top and the target braking pressure is not reached, the servo cylinder circuit isolation valve is closed, the servo motor is driven to reverse and drive the ball screw transmission mechanism to rotate, thereby driving the servo cylinder piston back to replenish fluid; after the servo cylinder piston retreats the preset stroke and then pushes forward until the preset conditions are met, the servo cylinder circuit isolation valve is opened and the servo cylinder piston continues to be pushed forward to reach the target braking pressure through relay pressure building.

[0026] Optionally, the method further includes:

[0027] In the pedal-operated electric braking mode, the brake-by-wire system is detected to see whether it satisfies a preset exit condition. If it is detected that the brake-by-wire system satisfies the preset exit condition, the brake-by-wire mode with uncompleted change is entered; if it is detected that the brake-by-wire system does not satisfy the preset exit condition, the brake-by-wire mode is maintained.

[0028] Optionally, detecting whether the brake-by-wire system satisfies a preset exit condition includes:

[0029] Detect whether the stroke of the mechanical push rod is less than the preset stroke value;

[0030] If the stroke of the mechanical push rod is less than the preset stroke value, it is determined that the wire control brake system meets the preset exit condition;

[0031] If the stroke of the mechanical push rod is greater than or equal to the preset stroke value, it is determined that the wire control brake system does not meet the preset exit condition; or,

[0032] Check whether the pressure of the manual cylinder is less than the preset pressure value;

[0033] If the pressure of the manual cylinder is less than a preset pressure value, it is determined that the brake-by-wire system meets a preset exit condition;

[0034] If the pressure of the manual cylinder is greater than or equal to the preset pressure value, it is determined that the brake-by-wire system does not meet the preset exit condition.

[0035] Optionally, detecting whether the brake-by-wire system is in a pedal-powered state includes:

[0036] If it is detected at the moment of power-on that the brake pedal is depressed, it is determined that the brake-by-wire system is in a pedal-depressed power-on state;

[0037] When the brake-by-wire system is in a pedal-on state, the brake-by-wire system exits the pedal-on state only after detecting that the brake pedal is fully released.

[0038] If it is detected at the moment of power-on that the brake pedal is not depressed, it is determined that the brake-by-wire system is not in the pedal-depressed power-on state.

[0039] Optionally, after entering the mechanical backup braking mode, the method further includes:

[0040] Control the manual cylinder circuit isolation valve to remain in the open state, and control the simulation cylinder circuit isolation valve and the servo cylinder circuit isolation valve to remain in the closed state, so that the two piston chambers of the manual cylinder are connected to the electronic body stability system and the wheel-side braking circuit. When the brake pedal is stepped on to build up pressure, the connected brake circuit pressure is built up normally, and the pressure is greater than 0. The circuit pressure from the simulation cylinder circuit isolation valve to the simulation cylinder is 0, and the pressure after the servo cylinder circuit isolation valve and in the servo cylinder is also 0.

[0041] Optionally, after entering the normal brake-by-wire mode, the method further includes:

[0042] The manual cylinder circuit isolation valve is controlled to change from an open state to a closed state, and the simulation cylinder circuit isolation valve and the servo cylinder circuit isolation valve are controlled to change from a closed state to an open state, and the pressure in the manual cylinder and the simulation cylinder is measured by the manual cylinder pressure sensor, and the pressure in the servo cylinder body, the front and rear hydraulic circuits of the servo cylinder circuit isolation valve, the electronic body stability system and the wheel side are measured by the servo cylinder pressure sensor.

[0043] According to a second aspect of the present application, a fully decoupled brake-by-wire system is provided, comprising: a controller, a brake pedal, a mechanical push rod, a travel sensor, a fluid reservoir, a manual cylinder including a piston and a spring, a manual cylinder pressure sensor, a manual cylinder circuit isolation valve, a simulation cylinder circuit isolation valve, a simulation cylinder, a servo cylinder circuit isolation valve, a servo cylinder pressure sensor, a servo cylinder body, a servo cylinder piston, a ball screw transmission mechanism, and a servo motor;

[0044] The controller is used to detect whether the wire control brake system is powered on normally; if the wire control brake system is not powered on normally, it enters the mechanical backup braking mode; if the wire control brake system is powered on normally, the motor completion homing mark is set to incomplete, and the wire control brake system is detected to have a fault; if the wire control brake system has a fault, it enters the mechanical backup braking mode; if the wire control brake system has no fault, it detects whether the wire control brake system is in the pedal power-on state; if the wire control brake system is in the pedal power-on state, it enters the pedal power-on braking mode; in the pedal power-on braking mode, the analog cylinder circuit isolation valve is controlled to remain in the closed state, and the manual cylinder circuit isolation valve is controlled to change from the open state to the closed state after power is supplied, and the first target braking pressure is determined according to the stroke of the mechanical push rod; the second target braking pressure is determined according to the pressure detected by the manual cylinder pressure sensor, the larger value of the first target braking pressure and the second target braking pressure is selected as the target braking pressure, and the braking pressure is output; and,

[0045] If the wire control braking system is not in the pedal-powered state, it detects whether there is a braking request; if there is a braking request, it determines whether the mechanical zero point of the servo cylinder piston has been detected based on the motor completion homing mark; if there is a braking request and the motor completion homing mark is completed, it is determined that the mechanical zero point of the servo cylinder piston has been detected, and the normal wire control braking mode is entered, and the braking request is responded to and the braking pressure corresponding to the braking request is output; if there is a braking request and the motor completion homing mark is not completed, it is determined that the mechanical zero point of the servo cylinder piston has not been detected, and the wire control braking mode with incomplete homing is entered, and the execution of the servo cylinder piston mechanical zero point detection is interrupted. process, and responds to the braking request and outputs the braking pressure corresponding to the braking request; if there is no braking request, judging whether the mechanical zero point of the servo cylinder piston has been detected based on the motor completion homing mark; if there is no braking request and the motor completion homing mark is completed, determining that the mechanical zero point of the servo cylinder piston has been detected, and entering the normal wire control braking mode; if there is no braking request and the motor completion homing mark is not completed, determining that the mechanical zero point of the servo cylinder piston has not been detected, executing the process of mechanical zero point detection of the servo cylinder piston, and when the mechanical zero point of the servo cylinder piston is detected, setting the motor completion homing mark to completed; and,

[0046] Detect whether the brake-by-wire system is powered off; if it is detected that the brake-by-wire system is not powered off, return to the step of detecting whether the brake-by-wire system is faulty; if it is detected that the brake-by-wire system is powered off, the process ends.

[0047] Optionally, the controller is also used to detect whether the target braking pressure is reached when the servo cylinder piston is pushed to the top during the process of pushing the servo cylinder piston forward to build pressure. If the servo cylinder piston is pushed to the top and the target braking pressure is not reached, the servo cylinder circuit isolation valve is closed, and the servo motor is driven to reverse and drive the ball screw transmission mechanism to rotate, thereby driving the servo cylinder piston back to replenish fluid; after the servo cylinder piston retreats a preset stroke and then pushes forward until the preset conditions are met, the servo cylinder circuit isolation valve is opened, and the servo cylinder piston continues to be pushed forward to achieve the target braking pressure through relay pressure building.

[0048] Optionally, the controller is also used to detect whether the wire control braking system meets the preset exit conditions in the pedal-on electric braking mode. If it is detected that the wire control braking system meets the preset exit conditions, the wire control braking mode with unfinished change is entered; if it is detected that the wire control braking system does not meet the preset exit conditions, the wire control braking mode continues to remain in the pedal-on electric braking mode.

[0049] Optionally, the controller is specifically configured to detect whether the brake-by-wire system meets a preset exit condition through the following steps:

[0050] Detect whether the stroke of the mechanical push rod is less than the preset stroke value;

[0051] If the stroke of the mechanical push rod is less than the preset stroke value, it is determined that the wire control brake system meets the preset exit condition;

[0052] If the stroke of the mechanical push rod is greater than or equal to the preset stroke value, it is determined that the wire control brake system does not meet the preset exit condition; or,

[0053] Check whether the pressure of the manual cylinder is less than the preset pressure value;

[0054] If the pressure of the manual cylinder is less than a preset pressure value, it is determined that the brake-by-wire system meets a preset exit condition;

[0055] If the pressure of the manual cylinder is greater than or equal to the preset pressure value, it is determined that the brake-by-wire system does not meet the preset exit condition.

[0056] Optionally, the controller is specifically configured to detect whether the brake-by-wire system is in a pedal-powered state by performing the following steps:

[0057] If it is detected at the moment of power-on that the brake pedal is depressed, it is determined that the brake-by-wire system is in a pedal-depressed power-on state;

[0058] When the brake-by-wire system is in a pedal-on state, the brake-by-wire system exits the pedal-on state only after detecting that the brake pedal is fully released.

[0059] If it is detected at the moment of power-on that the brake pedal is not depressed, it is determined that the brake-by-wire system is not in the pedal-depressed power-on state.

[0060] Optionally, the controller is also used to control the manual cylinder circuit isolation valve to remain open and control the simulation cylinder circuit isolation valve and the servo cylinder circuit isolation valve to remain closed after entering the mechanical backup braking mode, so that the two piston chambers of the manual cylinder are connected to the electronic body stability system and the wheel-side braking circuit. When the brake pedal is stepped on to build pressure, the connected braking circuit pressure is established normally, and the pressure is greater than 0. The circuit pressure from the simulation cylinder circuit isolation valve to the simulation cylinder is 0, and the pressure after the servo cylinder circuit isolation valve and in the servo cylinder is also 0.

[0061] Optionally, the controller is also used to control the manual cylinder circuit isolation valve to change from an open state to a closed state, and control the simulation cylinder circuit isolation valve and the servo cylinder circuit isolation valve to change from a closed state to an open state after entering the normal wire control braking mode, and measure the pressure in the manual cylinder and the simulation cylinder through the manual cylinder pressure sensor, and measure the pressure in the servo cylinder body, the front and rear hydraulic circuits of the servo cylinder circuit isolation valve, the electronic body stability system and the wheel side through the servo cylinder pressure sensor.

[0062] According to a third aspect of the present application, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the method described in the first aspect is implemented.

[0063] According to a fourth aspect of the present application, a computer program product is provided. When the computer program product is run on a computer, the computer is caused to execute the method described in the first aspect.

[0064] The technical solution provided by the embodiments of the present application has the following advantages compared with the prior art:

[0065] After detecting that the brake-by-wire system is powered on normally and has no faults, if the brake-by-wire system is in the pedal-powered state, the system enters the pedal-powered braking mode. If the brake-by-wire system is not in the pedal-powered state, the system checks for a braking request. If a braking request is received and homing has not yet been completed, the brake-by-wire operation with incomplete homing is prioritized, directly building pressure in the servo cylinder based on the braking target and responding to the braking request by delivering sufficient braking force. If a braking request is received and homing has been completed, the system enters the normal brake-by-wire mode and responds to the braking request by delivering sufficient braking force. If there is no braking request and homing has not yet been completed, homing continues, looping through the process until homing is complete. If there is no braking request and homing has been completed, the system enters the normal brake-by-wire mode. In this embodiment of the present application, if a braking request is received during the homing process, the braking request is prioritized, the homing operation is abandoned, and homing will not be performed until the brake request is released. Furthermore, if the homing process is interrupted, repeated homing attempts are made without a braking request until homing is successful. It can be seen that the present application prioritizes ensuring sufficient braking force output while being able to successfully complete power-on change. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0067] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0068] Figure 1 A schematic diagram of a fully decoupled brake-by-wire system in an embodiment of the present application;

[0069] Figure 2 A flow chart of a fully decoupled brake-by-wire method in an embodiment of the present application;

[0070] Figure 3A A schematic diagram of a fully decoupled brake-by-wire system in mechanical backup braking mode;

[0071] Figure 3B A schematic diagram of a fully decoupled brake-by-wire system in normal brake-by-wire mode;

[0072] Figure 4 This is another flow chart of the fully decoupled brake-by-wire method in the embodiment of the present application;

[0073] Figure 5Schematic diagram of the structure of a fully decoupled wire-controlled brake system in an embodiment of the present application. DETAILED DESCRIPTION

[0074] In order to more clearly understand the above-mentioned objectives, features and advantages of the present application, the scheme of the present application will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0075] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application can also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present application, not all of the embodiments.

[0076] The brake-by-wire system of the embodiment of the present application is a fully decoupled brake-by-wire system (DBS, Decoupled Brake System). Because of the isolation of the solenoid valve, it can achieve a fully decoupled state, that is, the pedal feel will not be affected by the execution circuit at all, and the pedal depression depth and the final output hydraulic pressure can be completely decoupled in the corresponding relationship. Therefore, it is convenient to perform many complex and intelligent control logics.

[0077] See also Figure 1 , Figure 1 This is a schematic diagram of the principle of a fully decoupled, wire-controlled brake system in an embodiment of the present application. The wire-controlled brake system includes: a brake pedal 1, a mechanical push rod 2, a travel sensor 3, a fluid reservoir 4, a first piston and spring 5 in the manual cylinder, a second piston and spring 6 in the manual cylinder, a manual cylinder pressure sensor 7, a manual cylinder circuit isolation valve 8, a manual cylinder circuit isolation valve 9, a simulation cylinder circuit isolation valve 10, a simulation cylinder 11, a servo cylinder circuit isolation valve 12, a servo cylinder circuit isolation valve 13, a servo cylinder pressure sensor 14, a servo cylinder body 15, a servo cylinder piston 16, a ball screw drive mechanism 17, and a servo motor 18. The remaining components are the brake fluid circuit and the associated filter and one-way valve. The circuit is filled with brake fluid, and the fluid level in the fluid reservoir 4 is between the minimum and maximum positions. The manual cylinder circuit isolation valves 8 and 9 are both normally open valves, while the simulation cylinder circuit isolation valves 10, the servo cylinder circuit isolation valves 12, and the servo cylinder circuit isolation valves 13 are all normally closed valves.

[0078] Figure 1 In the car, the Electronic Stability Control (ESC) connects to the two circuits of the DBS and to the four wheel brakes. The symbols FL, FR, RL, and RR in the figure represent the four wheel brakes, respectively.

[0079] See also Figure 2 , Figure 2This is a flow chart of a fully decoupled brake-by-wire method according to an embodiment of the present application, which may include the following steps:

[0080] Step S202 , detecting whether the brake-by-wire system is powered on normally.

[0081] If the brake-by-wire system is not powered on normally, step S204 is executed; if the brake-by-wire system is powered on normally, step S206 is executed.

[0082] Step S204: Entering the mechanical backup braking mode.

[0083] In mechanical backup braking mode, no control strategy is involved. If the brake-by-wire system is not powered on properly, manual cylinder circuit isolation valves 8 and 9 are controlled to remain open, while analog cylinder circuit isolation valves 10, servo cylinder circuit isolation valves 12, and servo cylinder circuit isolation valves 13 are controlled to remain closed.

[0084] Combine Figure 3A In the mechanical backup braking mode, the brake pedal 1 is depressed, pushing the mechanical push rod 2 to the left. At this time, the piston in the manual cylinder moves to the left, and the piston spring is compressed. After the piston in the manual cylinder moves to the left, it passes the brake fluid circuit inlet of the two piston chambers in the manual cylinder. The brake fluid in the two piston chambers of the manual cylinder is sealed and compressed, and the further the piston is pushed to the left, the higher the pressure in the sealed circuit. At this time, since the manual cylinder circuit isolation valve 8 and the manual cylinder circuit isolation valve 9 are in the open state, the two piston chambers of the manual cylinder are connected to the electronic stability control system and the wheel side brake circuit. When the brake pedal is depressed to build pressure, the pressure of the connected brake circuit is built up normally, and the pressure is greater than 0. The circuit pressure from the simulation cylinder circuit isolation valve to the simulation cylinder is 0, and the pressure after the servo cylinder circuit isolation valve and in the servo cylinder is also 0.

[0085] Step S2062, setting the motor homing completion flag to incomplete.

[0086] The Motor Home Completion Flag indicates whether the servo cylinder piston's mechanical zero point has been detected. If the Motor Home Completion Flag is "Incomplete," it indicates that the servo cylinder piston's mechanical zero point has not been detected. If the Motor Home Completion Flag is "Completed," it indicates that the servo cylinder piston's mechanical zero point has been detected. Each time the Brake-by-Wire system is powered on normally, the Motor Home Completion Flag is set to "Incomplete" because homing has not yet been performed.

[0087] Step S2064: Check whether there is any fault in the brake-by-wire system.

[0088] In this embodiment of the present application, a fault in the brake-by-wire system can be determined by detecting whether the servo motor, the manual cylinder circuit isolation valve, and the servo cylinder circuit isolation valve are faulty. If none of the servo motor, the manual cylinder circuit isolation valve, and the servo cylinder circuit isolation valve are faulty, the brake-by-wire system is determined to be faulty. If at least one of the servo motor, the manual cylinder circuit isolation valve, and the servo cylinder circuit isolation valve is faulty, the brake-by-wire system is determined to be faulty.

[0089] If there is a fault in the wire control braking system, step S204 is executed. At this time, the motor and all solenoid valves (manual cylinder circuit isolation valve 8, manual cylinder circuit isolation valve 9, simulation cylinder circuit isolation valve 10, servo cylinder circuit isolation valve 12 and servo cylinder circuit isolation valve 13) are not controlled; if there is no fault in the wire control braking system, step S208 is executed.

[0090] Step S208 , detecting whether the brake-by-wire system is in a pedal-powered state.

[0091] After powering on by pressing the brake pedal, as long as the driver has not completely released the brake pedal, the brake-by-wire system is considered to be in the pedal-on state. That is, if the brake pedal is detected as being pressed at the moment of powering on, i.e., the controller recognizes that the brake pedal is pressed at the moment of powering on, the brake-by-wire system is determined to be in the pedal-on state. Conversely, if the brake pedal is detected as not being pressed at the moment of powering on, i.e., the controller recognizes that the brake pedal is not pressed at the moment of powering on, the brake-by-wire system is determined to be not in the pedal-on state.

[0092] Once the brake-by-wire system is recognized as being in the pedal-on state, if the exit conditions are not met, the system remains in the pedal-on state. If the brake-by-wire system is in the pedal-on state, it will exit the pedal-on state only when the brake pedal is fully released.

[0093] If the brake-by-wire system is in the pedal-down power-on state, step S210 is executed; if the brake-by-wire system is not in the pedal-down power-on state, step S212 is executed.

[0094] Step S210: Entering the pedal-powered braking mode.

[0095] In pedal-powered braking mode, the analog cylinder circuit isolation valve remains closed, while the manual cylinder circuit isolation valve switches from open to closed upon power-up. A first target brake pressure is determined based on the stroke of the mechanical pushrod. A second target brake pressure is determined based on the pressure detected by the manual cylinder pressure sensor. The larger of the first and second target brake pressures is selected as the target brake pressure and output. Specifically, when a target brake pressure is set, the controller activates the motor, which, through the transmission mechanism, drives the servo cylinder piston to compress the brake fluid, establishing the corresponding brake pressure.

[0096] In this mode, the manual cylinder circuit isolation valve 8 and the manual cylinder circuit isolation valve 9 are closed at the moment the brake pedal is powered on, and the simulation cylinder circuit isolation valve 10 is kept closed. In this way, the brake fluid in the manual cylinder will be isolated from the circuits after the simulation cylinder circuit isolation valve 10 and after the manual cylinder circuit isolation valve 8 and the manual cylinder circuit isolation valve 9, thereby preventing the pedal from suddenly sinking when the brake pedal is powered on when it is deeply depressed.

[0097] Although the brake pedal cannot be depressed any further after the manual cylinder circuit isolation valve 8, the manual cylinder circuit isolation valve 9 and the simulation cylinder circuit isolation valve 10 are closed, if the force of pressing the brake pedal 1 is further increased, the measurement value of the manual cylinder pressure sensor 7 will increase further. The increase in this value will be used as a control basis to increase the target pressure of the braking system, thereby generating a greater braking pressure at the wheel side to meet the braking requirements.

[0098] Step S212: Detect whether there is a braking request.

[0099] If there is a braking request, step S214 is executed; if there is no braking request, step S220 is executed.

[0100] Step S214: judging whether the mechanical zero point of the servo cylinder piston has been detected based on the motor completing the zero mark.

[0101] If there is a braking request and the motor completion homing mark is completed, step S216 is executed; if there is a braking request and the motor completion homing mark is not completed, step S218 is executed.

[0102] Step S216 , determining that the mechanical zero point of the servo cylinder piston has been detected, entering the normal wire control brake mode, and responding to the braking request to output the braking pressure corresponding to the braking request.

[0103] Combine Figure 3BAfter entering the normal wire control braking mode, all solenoid valves are energized and activated, that is, the manual cylinder circuit isolation valve is controlled to change from an open state to a closed state, and the simulation cylinder circuit isolation valve and the servo cylinder circuit isolation valve are controlled to change from a closed state to an open state. The pressure in the manual cylinder and the simulation cylinder can be measured by the manual cylinder pressure sensor, and the pressure in the servo cylinder body, the hydraulic circuits before and after the servo cylinder circuit isolation valve, the electronic stability control system and the wheel side can be measured by the servo cylinder pressure sensor.

[0104] When the brake pedal is depressed, human-generated hydraulic pressure builds up before the manual cylinder circuit isolation valves 8 and 9. At this point, the pressure measured by the manual cylinder pressure sensor 7 represents the pressure in the manual cylinder and the simulated cylinder. Furthermore, the pressure generated by the servo motor 18 driving the ball screw drive mechanism 17 forward to compress the brake fluid in the servo cylinder piston 16 builds up in the fluid circuit after the manual cylinder circuit isolation valves 8 and 9. At this point, the pressure measured by the servo cylinder pressure sensor 14 represents the pressure in the hydraulic circuits before and after the servo cylinder body 15, the servo cylinder circuit isolation valves 12 and 13, and the pressure in the ESC and wheel side.

[0105] Step S218, determining that the mechanical zero point detection of the servo cylinder piston is not completed, entering the wire control brake mode with incomplete homing, interrupting the process of executing the mechanical zero point detection of the servo cylinder piston, responding to the braking request, and outputting the braking pressure corresponding to the braking request.

[0106] The control strategy for responding to braking requests in the incomplete homing brake-by-wire mode and the normal homing brake-by-wire mode is the same. The difference is that the motor corresponding to the normal homing brake-by-wire mode is marked as completed, and when there is a braking request, relevant control is executed to achieve corresponding braking pressure output. When there is no braking request, it continues to stay in this mode and wait for the execution of relevant control when there is a braking request. The motor corresponding to the incomplete homing brake-by-wire mode is marked as incomplete, and when there is a braking request, relevant control is executed to achieve corresponding braking pressure output. When there is no braking request, it exits this mode and waits for an opportunity to perform homing.

[0107] Step S220: Determine whether the mechanical zero point of the servo cylinder piston has been detected based on the motor completing the zero mark.

[0108] If there is no braking request and the motor completion homing mark is completed, step S222 is executed; if there is no braking request and the motor completion homing mark is not completed, step S224 is executed.

[0109] Step S222: Determine whether the mechanical zero point of the servo cylinder piston has been detected and enter the normal wire control brake mode.

[0110] Step S224, determining that the mechanical zero point of the servo cylinder piston has not been detected, executing the process of mechanical zero point detection of the servo cylinder piston, and when the mechanical zero point of the servo cylinder piston is detected, setting the motor homing completion mark to completed.

[0111] In the embodiment of the present application, if there is a braking request, the braking request is responded to first and the change action is abandoned. If there is no braking request, change is performed. The process of executing the mechanical zero point detection of the servo cylinder piston in step S224 can be executed multiple times through a loop process to finally complete the change.

[0112] Step S226 , detecting whether the brake-by-wire system is powered off.

[0113] If it is detected that the brake-by-wire system is not powered off, the process returns to step S2064; if it is detected that the brake-by-wire system is powered off, the process ends.

[0114] The brake-by-wire method of an embodiment of the present application, after detecting that the brake-by-wire system is powered on normally and has no faults, enters the pedal-powered braking mode if the brake-by-wire system is detected to be in the pedal-powered state. If the brake-by-wire system is detected to be not in the pedal-powered state, it detects whether there is a braking request. If there is a braking request and homing has not been completed, the brake-by-wire method prioritizing the uncompleted homing is executed, directly building pressure in the servo cylinder according to the braking target, and responding to the braking request by outputting sufficient braking force. If there is a braking request and homing has been completed, the method enters the normal brake-by-wire mode and responds to the braking request by outputting sufficient braking force. If there is no braking request and power-on homing has not been completed, homing continues, executing a loop until homing is completed. If there is no braking request and homing is completed, the method enters the normal brake-by-wire mode. In this embodiment of the present application, if a braking request is received during the homing process, the braking request is prioritized, the homing operation is abandoned, and homing is not performed until the braking request is released. Furthermore, if the homing process is interrupted, repeated homing attempts are made without a braking request until homing is successful. It can be seen that the present application prioritizes ensuring sufficient braking force output while being able to successfully complete power-on change.

[0115] Optionally, during the process of pushing the servo cylinder piston forward to build pressure, if the servo cylinder piston is pushed to the top and the target braking pressure is not reached, the servo cylinder circuit isolation valve is closed, the servo motor is driven to reverse and drive the ball screw transmission mechanism to rotate, thereby driving the servo cylinder piston back to replenish fluid; after the servo cylinder piston retreats a preset stroke and then pushes forward until the preset conditions are met, the servo cylinder circuit isolation valve is opened, and the servo cylinder piston continues to be pushed forward to reach the target braking pressure through relay pressure building, thereby ensuring sufficient braking force output.

[0116] In the pedal-operated braking mode, when the brake pedal is slightly released but not completely released, the vehicle may slip on a slope due to the reduction in the target pressure of the braking system. At this time, it is necessary to continue to press the pedal to increase the target braking force. However, because it is in the pedal-operated braking mode, the brake pedal cannot be continued to be pressed after it has been released to the point where it is not completely released, which may cause a poor experience.

[0117] In some embodiments, in order to avoid this problem, in the pedal-powered braking mode, if the preset exit condition (i.e., the condition for entering the normal brake-by-wire mode) is not met, the highest target braking pressure in this mode is always maintained (this highest target braking pressure will be subject to a maximum value limit, i.e., not exceeding the maximum braking pressure limit value in place) until the preset exit condition is met and the target braking pressure is released to 0. Subsequent braking enters the normal brake-by-wire mode, and the highest target pressure maintenance logic of the pedal-powered braking mode is no longer executed.

[0118] See also Figure 4 , Figure 4 This is another flow chart of the fully decoupled wire control brake method in the embodiment of the present application. Figure 2 Based on the embodiment, the following steps may also be included:

[0119] Step S2111: In the pedal-operated electric braking mode, detecting whether the brake-by-wire system meets a preset exit condition.

[0120] If it is detected that the wire control brake system meets the preset exit condition, step S2112 is executed; if it is detected that the wire control brake system does not meet the preset exit condition, it continues to remain in the pedal-on electric braking mode and step S226 is executed.

[0121] Step S2112, entering the brake-by-wire mode with unfinished change.

[0122] It is understandable that when the brake-by-wire system is in the pedaling power-on brake mode, it must not complete the power-on change. Therefore, when exiting the pedaling power-on brake mode, the brake-by-wire mode with incomplete change is entered to continue to perform change.

[0123] Alternatively, the stroke of the mechanical push rod may be detected to determine whether it is less than a preset stroke value; if so, the brake-by-wire system is determined to have satisfied a preset exit condition; if the stroke of the mechanical push rod is greater than or equal to the preset stroke value, the brake-by-wire system is determined to have not satisfied the preset exit condition. Alternatively, the pressure of the manual cylinder may be detected to determine whether it is less than a preset pressure value; if so, the brake-by-wire system is determined to have satisfied the preset exit condition; if the pressure of the manual cylinder is greater than or equal to the preset pressure value, the brake-by-wire system is determined to have not satisfied the preset exit condition.

[0124] By adopting the above method, it is possible to avoid the problem of poor experience caused by the inability to continue pressing the brake pedal after the brake pedal is released to a point where it is not completely released in the pedal-operated electric braking mode.

[0125] It should be noted that although the steps of the method of the present application are described in a specific order in the drawings, this does not require or imply that the steps must be performed in this specific order, or that all steps must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps.

[0126] The present application also provides a fully decoupled wire-controlled brake system. Figure 5 The fully decoupled brake-by-wire system 500 includes a controller 502, a brake pedal 504, a mechanical push rod 506, a travel sensor 508, a fluid reservoir 510, a manual cylinder 512 including a piston and a spring, a manual cylinder pressure sensor 514, a manual cylinder circuit isolation valve 516, a simulation cylinder circuit isolation valve 518, a simulation cylinder 520, a servo cylinder circuit isolation valve 522, a servo cylinder pressure sensor 524, a servo cylinder body 526, a servo cylinder piston 528, a ball screw transmission mechanism 530, and a servo motor 532.

[0127] Controller 502 is used to detect whether the wire control brake system is powered on normally; if the wire control brake system is not powered on normally, it enters the mechanical backup braking mode; if the wire control brake system is powered on normally, the motor completion homing mark is set to incomplete, and the wire control brake system is detected to have a fault; if the wire control brake system has a fault, it enters the mechanical backup braking mode; if the wire control brake system has no fault, it detects whether the wire control brake system is in the pedal power-on state; if the wire control brake system is in the pedal power-on state, it enters the pedal power-on braking mode; in the pedal power-on braking mode, the analog cylinder circuit isolation valve is controlled to remain in the closed state, and the manual cylinder circuit isolation valve is controlled to change from the open state to the closed state after power is supplied, and the first target braking pressure is determined according to the stroke of the mechanical push rod; the second target braking pressure is determined according to the pressure detected by the manual cylinder pressure sensor, the larger value of the first target braking pressure and the second target braking pressure is selected as the target braking pressure, and the braking pressure is output; and,

[0128] If the wire control brake system is not in the pedal power-on state, it detects whether there is a braking request; if there is a braking request, it determines whether the mechanical zero point of the servo cylinder piston has been detected based on the motor completion homing mark; if there is a braking request and the motor completion homing mark is completed, it is determined that the mechanical zero point of the servo cylinder piston has been detected, and the system enters the normal wire control brake mode, responds to the braking request, and outputs the braking pressure corresponding to the braking request; if there is a braking request and the motor completion homing mark is not completed, it is determined that the mechanical zero point of the servo cylinder piston has not been detected, and the system enters the wire control brake mode with incomplete homing, and the execution of the servo cylinder piston mechanical zero point detection is interrupted. process, and responds to the braking request and outputs the braking pressure corresponding to the braking request; if there is no braking request, it is determined whether the mechanical zero point of the servo cylinder piston has been detected according to the motor completion home mark; if there is no braking request and the motor completion home mark is completed, it is determined that the mechanical zero point of the servo cylinder piston has been detected and the normal wire control braking mode is entered; if there is no braking request and the motor completion home mark is not completed, it is determined that the mechanical zero point of the servo cylinder piston has not been detected, and the process of mechanical zero point detection of the servo cylinder piston is executed, and when the mechanical zero point of the servo cylinder piston is detected, the motor completion home mark is set to completed; and,

[0129] Check whether the brake-by-wire system is powered off; if it is detected that the brake-by-wire system is not powered off, return to the step of checking whether the brake-by-wire system is faulty; if it is detected that the brake-by-wire system is powered off, the process ends.

[0130] Optionally, the controller 502 is also used to detect whether the target braking pressure is reached when the servo cylinder piston is pushed to the top during the process of pushing the servo cylinder piston forward to build pressure. If the servo cylinder piston is pushed to the top and the target braking pressure is not reached, the servo cylinder circuit isolation valve is closed, the servo motor is driven to reverse and drive the ball screw transmission mechanism to rotate, and then the servo cylinder piston is driven back to replenish fluid; after the servo cylinder piston retreats a preset stroke and then pushes forward until the preset conditions are met, the servo cylinder circuit isolation valve is opened, and the servo cylinder piston continues to be pushed forward to achieve the target braking pressure through relay pressure building.

[0131] Optionally, the controller 502 is also used to detect whether the wire control brake system meets the preset exit conditions in the pedal-on electric braking mode. If it is detected that the wire control brake system meets the preset exit conditions, the wire control brake mode with unfinished change is entered; if it is detected that the wire control brake system does not meet the preset exit conditions, the brake mode continues to remain in the pedal-on electric braking mode.

[0132] Optionally, the controller 502 is specifically configured to detect whether the brake-by-wire system meets a preset exit condition through the following steps:

[0133] Detect whether the stroke of the mechanical push rod is less than the preset stroke value;

[0134] If the stroke of the mechanical push rod is less than the preset stroke value, it is determined that the brake-by-wire system meets the preset exit condition;

[0135] If the stroke of the mechanical push rod is greater than or equal to the preset stroke value, it is determined that the brake-by-wire system does not meet the preset exit condition; or,

[0136] Check whether the pressure of the manual cylinder is less than the preset pressure value;

[0137] If the pressure of the manual cylinder is less than the preset pressure value, it is determined that the brake-by-wire system meets the preset exit condition;

[0138] If the pressure of the manual cylinder is greater than or equal to the preset pressure value, it is determined that the brake-by-wire system does not meet the preset exit condition.

[0139] Optionally, the controller 502 is specifically configured to detect whether the brake-by-wire system is in a pedal-powered state by performing the following steps:

[0140] If the brake pedal is detected to be depressed at the moment of power-on, it is determined that the brake-by-wire system is in the pedal-on state;

[0141] When the brake-by-wire system is in the pedal-on state, it will exit the pedal-on state only when it detects that the brake pedal is fully released;

[0142] If it is detected at the moment of power-on that the brake pedal is not depressed, it is determined that the brake-by-wire system is not in the pedal-depressed power-on state.

[0143] Optionally, the controller 502 is also used to control the manual cylinder circuit isolation valve to remain open and control the simulation cylinder circuit isolation valve and the servo cylinder circuit isolation valve to remain closed after entering the mechanical backup braking mode, so that the two piston chambers of the manual cylinder are connected to the electronic body stability system and the wheel-side braking circuit. When the brake pedal is stepped on to build up pressure, the connected braking circuit pressure is established normally, and the pressure is greater than 0. The circuit pressure from the simulation cylinder circuit isolation valve to the simulation cylinder is 0, and the pressure after the servo cylinder circuit isolation valve and in the servo cylinder is also 0.

[0144] Optionally, the controller 502 is also used to control the manual cylinder circuit isolation valve to change from an open state to a closed state, and control the simulation cylinder circuit isolation valve and the servo cylinder circuit isolation valve to change from a closed state to an open state after entering the normal wire control braking mode, and measure the pressure in the manual cylinder and the simulation cylinder through the manual cylinder pressure sensor, and measure the pressure in the servo cylinder body, the front and rear hydraulic circuits of the servo cylinder circuit isolation valve, the electronic body stability system and the wheel side through the servo cylinder pressure sensor.

[0145] The specific details of each module or unit in the above system have been described in detail in the corresponding method, so they will not be repeated here.

[0146] It should be noted that, although several modules or units of the device for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiment of the application, the features and functions of two or more modules or units described above can be concretized in one module or unit. On the contrary, the features and functions of one module or unit described above can be further divided into multiple modules or units to be concretized.

[0147] In an embodiment of the present application, a computer-readable storage medium is further provided, on which a computer program is stored. When the computer program is executed by a processor, the above-mentioned wire control braking method is implemented.

[0148] It should be noted that the computer-readable storage medium shown in this application can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or component, or any combination thereof. More specific examples of computer-readable storage media can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, device or device. The program code contained on the computer-readable storage medium can be transmitted using any appropriate medium, including but not limited to: wireless, wire, optical cable, radio frequency, etc., or any suitable combination thereof.

[0149] In an embodiment of the present application, a computer program product is further provided. When the computer program product is run on a computer, the computer is caused to execute the above-mentioned brake-by-wire method.

[0150] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0151] The foregoing description is intended only to provide specific embodiments of the present application, which will enable those skilled in the art to understand and implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments described herein, but is intended to be construed in the broadest manner consistent with the principles and novel features disclosed herein.

Claims

1. A fully decoupled wire control brake method, characterized in that: include: Check whether the brake-by-wire system is powered on normally; If the wire control brake system is not powered on normally, the system enters the mechanical backup brake mode; If the brake-by-wire system is powered on normally, setting the motor homing completion flag to incomplete, and detecting whether the brake-by-wire system has a fault; If there is a fault in the brake-by-wire system, a mechanical backup braking mode is entered; If there is no fault in the brake-by-wire system, detecting whether the brake-by-wire system is in a pedal-on state; If the brake-by-wire system is in a pedal-on power-up state, entering a pedal-on power-up braking mode; In the pedal-powered braking mode, the analog cylinder circuit isolation valve is controlled to remain in a closed state, and the manual cylinder circuit isolation valve is controlled to change from an open state to a closed state after power is applied. A first target brake pressure is determined according to the stroke of the mechanical push rod; a second target brake pressure is determined according to the pressure detected by the manual cylinder pressure sensor, and the larger value of the first target brake pressure and the second target brake pressure is selected as the target brake pressure, and the brake pressure is output; If the brake-by-wire system is not in a pedal-powered state, detecting whether there is a braking request; If there is a braking request, the motor will complete the zero mark to determine whether the mechanical zero point of the servo cylinder piston has been detected; If there is a braking request and the motor has completed the homing mark, it is determined that the mechanical zero point of the servo cylinder piston has been detected, the normal wire control braking mode is entered, and the braking request is responded to by outputting a braking pressure corresponding to the braking request; If there is a braking request and the motor homing completion mark is incomplete, it is determined that the mechanical zero point detection of the servo cylinder piston is incomplete, the homing is not completed, the wire control braking mode of the incomplete homing is entered, the process of executing the mechanical zero point detection of the servo cylinder piston is interrupted, and the braking request is responded to by outputting the braking pressure corresponding to the braking request; If there is no braking request, judging whether the mechanical zero point of the servo cylinder piston has been detected according to the motor completion homing mark; If there is no braking request and the motor has completed the homing mark, it is determined that the mechanical zero point of the servo cylinder piston has been detected and the normal wire control braking mode is entered; If there is no braking request and the motor homing completion mark is not completed, it is determined that the mechanical zero point detection of the servo cylinder piston is not completed, the process of the servo cylinder piston mechanical zero point detection is executed, and when the mechanical zero point detection of the servo cylinder piston is completed, the motor homing completion mark is set to completed; detecting whether the brake-by-wire system is powered off; If it is detected that the brake-by-wire system is not powered off, returning to the step of detecting whether the brake-by-wire system has a fault; If it is detected that the brake-by-wire system is powered off, the process ends.

2. The method according to claim 1, characterized in that The method further comprises: During the process of pushing the servo cylinder piston forward to build pressure, if the servo cylinder piston is pushed to the top and the target braking pressure is not reached, the servo cylinder circuit isolation valve is closed, the servo motor is driven to reverse and drive the ball screw transmission mechanism to rotate, thereby driving the servo cylinder piston back to replenish fluid; after the servo cylinder piston retreats the preset stroke and then pushes forward until the preset conditions are met, the servo cylinder circuit isolation valve is opened and the servo cylinder piston continues to be pushed forward to reach the target braking pressure through relay pressure building.

3. The method according to claim 1, characterized in that The method further comprises: In the pedal-operated power-on braking mode, detecting whether the brake-by-wire system satisfies a preset exit condition, and if it is detected that the brake-by-wire system satisfies the preset exit condition, entering a brake-by-wire mode with unfinished change; If it is detected that the brake-by-wire system does not meet the preset exit condition, the brake-by-wire system continues to be in the pedal-on electric braking mode.

4. The method according to claim 3, characterized in that The detecting whether the brake-by-wire system satisfies a preset exit condition includes: Detect whether the stroke of the mechanical push rod is less than the preset stroke value; If the stroke of the mechanical push rod is less than the preset stroke value, it is determined that the wire control brake system meets the preset exit condition; If the stroke of the mechanical push rod is greater than or equal to the preset stroke value, it is determined that the wire control brake system does not meet the preset exit condition; or, Check whether the pressure of the manual cylinder is less than the preset pressure value; If the pressure of the manual cylinder is less than a preset pressure value, it is determined that the brake-by-wire system meets a preset exit condition; If the pressure of the manual cylinder is greater than or equal to the preset pressure value, it is determined that the brake-by-wire system does not meet the preset exit condition.

5. The method according to claim 1, wherein The detecting whether the brake-by-wire system is in a pedal-powered state includes: If it is detected at the moment of power-on that the brake pedal is depressed, it is determined that the brake-by-wire system is in a pedal-depressed power-on state; When the brake-by-wire system is in a pedal-on state, the brake-by-wire system exits the pedal-on state only after detecting that the brake pedal is fully released. If it is detected at the moment of power-on that the brake pedal is not depressed, it is determined that the brake-by-wire system is not in the pedal-depressed power-on state.

6. The method according to claim 1, wherein After entering the mechanical backup braking mode, the method further includes: Control the manual cylinder circuit isolation valve to remain in the open state, and control the simulation cylinder circuit isolation valve and the servo cylinder circuit isolation valve to remain in the closed state, so that the two piston chambers of the manual cylinder are connected to the electronic body stability system and the wheel-side braking circuit. When the brake pedal is stepped on to build up pressure, the connected brake circuit pressure is built up normally, and the pressure is greater than 0. The circuit pressure from the simulation cylinder circuit isolation valve to the simulation cylinder is 0, and the pressure after the servo cylinder circuit isolation valve and in the servo cylinder is also 0.

7. The method according to claim 1, characterized in that After entering the normal brake-by-wire mode, the method further includes: The manual cylinder circuit isolation valve is controlled to change from an open state to a closed state, and the simulation cylinder circuit isolation valve and the servo cylinder circuit isolation valve are controlled to change from a closed state to an open state. The pressure in the manual cylinder and the simulation cylinder is measured by the manual cylinder pressure sensor, and the pressure in the servo cylinder body, the hydraulic circuits before and after the servo cylinder circuit isolation valve, the electronic body stability system and the wheel side are measured by the servo cylinder pressure sensor.

8. A fully decoupled brake-by-wire system, characterized in that: include: Controller, brake pedal, mechanical push rod, travel sensor, fluid reservoir, manual cylinder including piston and spring, manual cylinder pressure sensor, manual cylinder circuit isolation valve, simulation cylinder circuit isolation valve, simulation cylinder, servo cylinder circuit isolation valve, servo cylinder pressure sensor, servo cylinder body, servo cylinder piston, ball screw transmission mechanism and servo motor; The controller is configured to detect whether the brake-by-wire system is powered on normally; if the brake-by-wire system is not powered on normally, enter a mechanical backup braking mode; if the brake-by-wire system is powered on normally, set a motor homing completion flag to incomplete and detect whether the brake-by-wire system has a fault; If the brake-by-wire system has a fault, the system enters a mechanical backup braking mode; if the brake-by-wire system does not have a fault, the system detects whether the brake-by-wire system is in a pedal-powered state; If the brake-by-wire system is in the pedal-powered state, it enters the pedal-powered braking mode; in the pedal-powered braking mode, the analog cylinder circuit isolation valve is controlled to remain in the closed state, and the manual cylinder circuit isolation valve is controlled to change from the open state to the closed state after power is applied, and a first target brake pressure is determined according to the stroke of the mechanical push rod; a second target brake pressure is determined according to the pressure detected by the manual cylinder pressure sensor, and the larger value of the first target brake pressure and the second target brake pressure is selected as the target brake pressure, and the brake pressure is output; and, If the wire control brake system is not in the pedal-powered state, it detects whether there is a braking request; if there is a braking request, it determines whether the mechanical zero point of the servo cylinder piston has been detected based on the motor completion homing mark; if there is a braking request and the motor completion homing mark is completed, it is determined that the mechanical zero point of the servo cylinder piston has been detected, and the normal wire control brake mode is entered; if there is a braking request and the motor completion homing mark is not completed, it is determined that the mechanical zero point of the servo cylinder piston has not been detected, the process of executing the servo cylinder piston mechanical zero point detection is interrupted, and the wire control brake mode with unfinished homing is entered, and the braking request is responded to. and outputs a braking pressure corresponding to the braking request; if there is no braking request, judging whether the mechanical zero point of the servo cylinder piston has been detected according to the motor completion homing mark; if there is no braking request and the motor completion homing mark is completed, determining that the mechanical zero point of the servo cylinder piston has been detected, and entering the normal wire control braking mode; if there is no braking request and the motor completion homing mark is not completed, determining that the mechanical zero point of the servo cylinder piston has not been detected, executing the process of mechanical zero point detection of the servo cylinder piston, and when the mechanical zero point of the servo cylinder piston is detected, setting the motor completion homing mark to completed; as well as, Detect whether the brake-by-wire system is powered off; if it is detected that the brake-by-wire system is not powered off, return to the step of detecting whether the brake-by-wire system is faulty; if it is detected that the brake-by-wire system is powered off, the process ends.

9. The system according to claim 8, characterized in that The controller is also used to detect whether the target braking pressure is reached when the servo cylinder piston is pushed to the top during the process of pushing the servo cylinder piston forward to build pressure. If the servo cylinder piston is pushed to the top and the target braking pressure is not reached, the servo cylinder circuit isolation valve is closed, the servo motor is driven to reverse and drive the ball screw transmission mechanism to rotate, and then the servo cylinder piston is driven back to replenish fluid; after the servo cylinder piston retreats a preset stroke and then pushes forward until the preset conditions are met, the servo cylinder circuit isolation valve is opened, and the servo cylinder piston is pushed forward again to achieve the target braking pressure through relay pressure building.

10. The system according to claim 8, wherein: The controller is further configured to detect whether the brake-by-wire system satisfies a preset exit condition in the pedal-on electric braking mode; if it is detected that the brake-by-wire system satisfies the preset exit condition, the controller enters a brake-by-wire mode with uncompleted change; and if it is detected that the brake-by-wire system does not satisfy the preset exit condition, the controller continues to remain in the pedal-on electric braking mode.

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