Main-cylinder pressure processing method and apparatus, and redundant braking system and vehicle

Abstract

A main-cylinder pressure processing method and apparatus, and a redundant braking system and a vehicle, which are applied to the technical field of brake-by-wire. The method comprises: when a vehicle is in a first braking state, acquiring a pressure change rate in an ABS of the vehicle, and controlling, on the basis of the pressure change rate in the ABS, the vehicle to enter a correction state from the first braking state; when the vehicle is in the correction state, acquiring wheel information, insufficient braking information, overbraking information and characteristic information of the vehicle as whole vehicle information of the vehicle, and obtaining a main-cylinder estimation pressure of the vehicle on the basis of the whole vehicle information; performing detection on a main-cylinder pressure of the vehicle at a current moment on the basis of a failure condition; and when it is detected that the main-cylinder pressure meets the failure condition, replacing the main-cylinder pressure with the main-cylinder estimation pressure and outputting the main-cylinder estimation pressure. The method realizes accurate estimation and correction of a main-cylinder pressure in a hydraulic system of a vehicle, thereby effectively improving the precision of the main-cylinder pressure, and thus ensuring the functional safety of a brake-by-wire system.

Description

Master cylinder pressure handling methods, devices, redundant braking systems, and vehicles Technical Field

[0001] This invention relates to the field of brake-by-wire technology, and in particular to master cylinder pressure handling methods, devices, redundant braking systems, and vehicles. Background Technology

[0002] Brake-by-wire (BBW) is an emerging automotive braking technology that eliminates the direct mechanical connection between the brake pedal and the brake system. Instead, it uses electronic sensors to detect the driver's braking intentions, which are then processed by the Electronic Control Unit (ECU) to ultimately control the braking force output by the brake actuator. Therefore, the core of BBW is accurately identifying the driver's braking intentions, and the master cylinder pressure signal from the hydraulic system is one of the key signals for this identification.

[0003] The master cylinder pressure signal in a hydraulic system is typically based on the feedback signal from the master cylinder pressure sensor. However, due to environmental factors such as humidity and temperature, master cylinder pressure sensor failure is unavoidable. Once the master cylinder pressure sensor fails, the brake-by-wire system will be unable to obtain an accurate master cylinder pressure signal, thus affecting the functional safety of the brake-by-wire system.

[0004] In response to this issue, related technologies estimate the master cylinder pressure based on the relationship between the master cylinder piston displacement and the master cylinder pressure when the master cylinder pressure sensor fails. This estimated pressure is then output as a master cylinder pressure signal to address the problem of master cylinder pressure sensor failure detection. However, master cylinder pressure is often affected by various factors such as wheel characteristics, vehicle speed characteristics, pump pressure build-up, and braking force. Current technologies only consider the master cylinder's movement when estimating master cylinder pressure, lacking consideration of other key factors, thus requiring improvement in the accuracy of master cylinder pressure estimation.

[0005] Summary of the Invention

[0006] The purpose of this invention is to at least partially solve one of the technical problems existing in the prior art.

[0007] Therefore, the purpose of this invention is to provide a master cylinder pressure handling method, apparatus, redundant braking system, and vehicle.

[0008] To achieve the above-mentioned technical objectives, the technical solutions adopted in the embodiments of the present invention include:

[0009] On one hand, embodiments of the present invention provide a method for handling master cylinder pressure, including the following steps:

[0010] When the vehicle is in the first braking state, the pressure change rate inside the vehicle's anti-lock braking system is acquired, and the vehicle is controlled to enter the correction state from the first braking state based on the pressure change rate inside the anti-lock braking system; wherein, the first braking state is used to characterize the state of the vehicle when the anti-lock braking system is activated and the electronic brake-force distribution system is deactivated, and the pressure change rate is used to characterize the amount of pressure change inside the anti-lock braking system per unit time.

[0011] When the vehicle is in the correction state, the wheel information, under-braking information, over-braking information and characteristic information of the vehicle are acquired as the vehicle information, and the estimated pressure of the master cylinder of the vehicle is obtained based on the vehicle information.

[0012] Based on the failure condition, the master cylinder pressure of the vehicle at the current moment is detected; wherein, the failure condition includes either the master cylinder pressure being invalid or the master cylinder pressure exceeding a preset value range when the master cylinder pressure is valid;

[0013] When the master cylinder pressure is detected to meet the failure condition, the master cylinder pressure is replaced with the estimated master cylinder pressure and output.

[0014] On the other hand, embodiments of the present invention provide a master cylinder pressure processing device, including:

[0015] The state machine control module is used to acquire the pressure change rate inside the anti-lock braking system of the vehicle when the vehicle is in the first braking state, and control the vehicle to enter the correction state from the first braking state according to the pressure change rate inside the anti-lock braking system; wherein, the first braking state is used to characterize the state of the vehicle when the anti-lock braking system is activated and the electronic brake-force distribution system is deactivated, and the pressure change rate is used to characterize the amount of pressure change inside the anti-lock braking system per unit time.

[0016] The pressure estimation module is used to acquire the vehicle's wheel information, under-braking information, over-braking information and characteristic information as the vehicle's overall information when the vehicle is in the correction state, and to obtain the estimated pressure of the vehicle's master cylinder based on the overall vehicle information.

[0017] The detection module is used to detect the master cylinder pressure of the vehicle at the current moment according to the failure condition; and when the master cylinder pressure is detected to meet the failure condition, to replace the master cylinder pressure with the estimated master cylinder pressure and output it; wherein the failure condition includes either the master cylinder pressure being invalid or the master cylinder pressure exceeding a preset numerical range when the master cylinder pressure is valid.

[0018] On another front, embodiments of the present invention provide a redundant braking system that processes the pressure of the master cylinder using the master cylinder pressure processing method described above.

[0019] In another aspect, embodiments of the present invention provide a vehicle including the aforementioned master cylinder pressure processing device and / or the aforementioned electronic device.

[0020] The beneficial effects of this invention are as follows: It provides a master cylinder pressure processing method, device, redundant braking system, and vehicle. First, when the vehicle is in the first braking state, the pressure change rate inside the vehicle's anti-lock braking system (ABS) is acquired, and based on the pressure change rate inside the ABS, the vehicle is controlled to enter the correction state from the first braking state. Then, when the vehicle is in the correction state, wheel information, under-braking information, over-braking information, and characteristic information are acquired as the vehicle's overall information, and the estimated master cylinder pressure is obtained based on the overall vehicle information. Next, the master cylinder pressure at the current moment is detected according to the failure condition. Finally, when the master cylinder pressure is detected to meet the failure condition, the estimated master cylinder pressure is replaced with the actual master cylinder pressure and output. In the event of master cylinder pressure sensor failure, this invention accurately estimates and corrects the master cylinder pressure in the vehicle's hydraulic system by utilizing the vehicle state machine and various factors such as wheel characteristics, vehicle speed characteristics, pump pressure build-up, and braking force, effectively improving the accuracy of the master cylinder pressure and thus ensuring the functional safety of the brake-by-wire system. Attached Figure Description

[0021] Figure 1 is a flowchart of the master cylinder pressure processing method provided by the present invention;

[0022] Figure 2 is a schematic diagram of the vehicle state machine provided by the present invention;

[0023] Figure 3 is a flowchart of the switching from the first braking state to the correction state provided by the present invention;

[0024] Figure 4 is a flowchart of switching from the first braking state to the second braking state provided by the present invention;

[0025] Figure 5 is a flowchart of switching from the second braking state to the first braking state provided by the present invention;

[0026] Figure 6 is a flowchart of entering the initial state provided by the present invention;

[0027] Figure 7 is a flowchart of the switching from the initial state to the second braking state provided by the present invention;

[0028] Figure 8 is a flowchart of the switching from the initial state to the correction state provided by the present invention;

[0029] Figure 9 is a flowchart of estimating the pressure of the master cylinder provided by the present invention;

[0030] Figure 10 is another flowchart for estimating the pressure of the master cylinder provided by the present invention;

[0031] Figure 11 is a structural diagram of the main cylinder pressure processing device provided by the present invention;

[0032] Figure 12 is a schematic diagram of the principle of processing master cylinder pressure provided by the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0034] The present application will be further described below with reference to the accompanying drawings and specific embodiments. The described embodiments should not be considered as limitations on the present application, and all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present application.

[0035] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0037] First, the nouns and terms used in this invention will be explained:

[0038] ABS: Antilock Brake System.

[0039] EBD: Electronic Brakeforce Distribution.

[0040] Under-braking condition: The braking condition of a vehicle when the overall vehicle deceleration is less than the driver's braking deceleration.

[0041] Over-braking condition: The braking condition of a vehicle when the deceleration of the entire vehicle is greater than the braking deceleration of the driver.

[0042] Front axle engine drag torque: In non-driving conditions, the resistance torque generated by the engine located at the front of the vehicle on the rotating shaft due to internal friction and hydraulic resistance.

[0043] Rear axle engine drag torque: In non-drive mode, the resistance torque generated by the engine located at the rear of the vehicle on the rotating shaft due to internal friction and hydraulic resistance.

[0044] Wheel valve strategy: The strategies and mechanisms used in a vehicle's braking system to control the braking force of the wheels.

[0045] Pump pressure building action: In the vehicle's hydraulic system, the pump draws hydraulic oil from the tank and pressurizes it through the pipelines and valves in the hydraulic system to build up and maintain the pressure level required by the hydraulic system.

[0046] Pump half-open: During the pump pressure building process, the pump is in a working state when its displacement reaches a certain intermediate value.

[0047] Pump fully open: The operating state of the pump at its maximum displacement during the pump pressure building process.

[0048] Pump operation rate of change: The frequency of pump pressure build-up during the pump's pressure build-up process.

[0049] Braking force deviation value: The braking force deviation value when the vehicle is stopped.

[0050] Counting time: The duration of the vehicle's braking operation.

[0051] The present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments.

[0052] Brake-by-wire is an emerging automotive braking technology that eliminates the direct mechanical connection between the brake pedal and the brake system. Instead, it uses electronic sensors to detect the driver's braking intentions, processes these signals through an electronic control unit, and ultimately controls the brake actuator to output braking force. Therefore, the core of brake-by-wire is accurately recognizing the driver's braking intentions, and the master cylinder pressure signal from the hydraulic system is one of the key signals for identifying these intentions.

[0053] The master cylinder pressure signal in a hydraulic system is typically based on the feedback signal from the master cylinder pressure sensor. However, due to environmental factors such as humidity and temperature, master cylinder pressure sensor failure is unavoidable. Once the master cylinder pressure sensor fails, the brake-by-wire system will be unable to obtain an accurate master cylinder pressure signal, thus affecting the functional safety of the brake-by-wire system.

[0054] In response to this issue, related technologies estimate the master cylinder pressure based on the relationship between the master cylinder piston displacement and the master cylinder pressure when the master cylinder pressure sensor fails. This estimated pressure is then output as a master cylinder pressure signal to address the problem of master cylinder pressure sensor failure detection. However, master cylinder pressure is often affected by various factors such as wheel characteristics, vehicle speed characteristics, pump pressure build-up, and braking force. Current technologies only consider the master cylinder's movement when estimating master cylinder pressure, lacking consideration of other key factors, thus requiring improvement in the accuracy of master cylinder pressure estimation.

[0055] In view of this, the present invention provides a master cylinder pressure processing method, device, redundant braking system, and vehicle, which aims to accurately estimate and correct the master cylinder pressure in the vehicle's hydraulic system by utilizing the vehicle state machine and various factors such as the vehicle's wheel characteristics, overall vehicle speed characteristics, pump pressure build-up action, and braking force when the master cylinder pressure sensor fails. This effectively improves the accuracy of the master cylinder pressure and thus ensures the functional safety of the brake-by-wire system.

[0056] First, the implementation steps of the master cylinder pressure treatment method provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0057] The master cylinder pressure processing method provided by this invention can be applied to terminals, servers, or software running on either terminal or server. Terminals can be tablets, laptops, desktop computers, etc., but are not limited to these. Servers can be independent physical servers, server clusters or distributed systems composed of multiple physical servers, or cloud servers providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, content delivery networks, and big data and artificial intelligence platforms. Furthermore, a server can also be a node server in a blockchain network, but is not limited to these. Blockchain is a new application model of computer technologies such as distributed data storage, peer-to-peer transmission, consensus mechanisms, and encryption algorithms.

[0058] Referring to Figures 1 and 2, Figure 1 is a flowchart of the master cylinder pressure processing method provided by the present invention, and Figure 2 is a schematic diagram of the vehicle state machine provided by the present invention. The master cylinder pressure processing method provided by the present invention mainly includes the following steps S101-S104.

[0059] S101, when the vehicle is in the first braking state, the pressure change rate inside the vehicle's anti-lock braking system is obtained, and the vehicle is controlled to enter the correction state from the first braking state based on the pressure change rate inside the anti-lock braking system.

[0060] It should be noted that the first braking state refers to the vehicle's state when ABS is activated and EBD is deactivated; the correction state refers to the vehicle's state when the pressure change rate inside the ABS exceeds a preset threshold, provided that ABS is activated and EBD is deactivated. Specifically, deactivating EBD means that the EBD function controlling the vehicle is in an inactive state, while activating ABS means that the ABS function controlling the vehicle is in an active state.

[0061] It is understandable that the pressure change rate inside ABS refers to the amount of pressure change inside ABS per unit time.

[0062] In this step, when the vehicle activates ABS and deactivates EBD, the vehicle enters the first braking state. After entering the first braking state, the pressure change within the vehicle's ABS system is acquired per unit time, and based on this pressure change, it is determined whether the vehicle meets the conditions for entering the correction state. When the vehicle meets the conditions for entering the correction state, the vehicle is controlled to switch from the first braking state to the correction state.

[0063] S102, when the vehicle is in the correction state, the vehicle's wheel information, under-braking information, over-braking information and characteristic information are acquired as the vehicle's overall information, and the estimated pressure of the vehicle's master cylinder is obtained based on the overall vehicle information.

[0064] It should be noted that wheel information refers to wheel characteristic parameters, which may include, but are not limited to, the vehicle's front axle engine drag torque, rear axle engine drag torque, overall vehicle target pressure, vehicle speed, wheel speed signal quality, wheel control mode, wheel valve strategy, and wheel target braking torque.

[0065] Under-braking information refers to the characteristic parameters of a vehicle under under-braking conditions. It may include, but is not limited to, the under-braking status setpoint and under-braking ratio coefficient, as well as the vehicle's overall acceleration, rate of change of overall acceleration, master cylinder pressure, master cylinder pressure correction value, pump action rate of change, and braking force deviation value under under-braking conditions.

[0066] Over-braking information refers to the characteristic parameters of a vehicle under over-braking conditions. It may include, but is not limited to, the master cylinder pressure, master cylinder pressure correction value, master cylinder pressure change rate, vehicle speed, pump action change rate, and counting time under over-braking conditions.

[0067] Characteristic information refers to the overall vehicle characteristic parameters, which may include, but are not limited to, the vehicle's overall acceleration, overall deceleration, average deceleration proportional coefficient, and hydraulic system characteristic parameters.

[0068] Understandably, both under-braking and over-braking conditions fall under the category of vehicle braking force conditions.

[0069] In this step, after controlling the vehicle to enter the correction state from the first braking state, the vehicle's wheel information, under-braking information, over-braking information and characteristic information are acquired as the vehicle's overall information. Based on this information, the master cylinder pressure is estimated and corrected to obtain the estimated value of the vehicle's master cylinder pressure, i.e., the estimated master cylinder pressure.

[0070] S103, based on the failure condition, detect the main cylinder pressure of the vehicle at the current moment.

[0071] It should be noted that the failure condition is mainly used to detect whether the master cylinder pressure sensor has failed, and it mainly includes any one of the following sub-conditions (1)-(2):

[0072] (1) The master cylinder pressure is ineffective;

[0073] (2) When the master cylinder pressure is effective, the master cylinder pressure exceeds the preset value range.

[0074] For the above sub-condition (1), when the master cylinder pressure is invalid, it means that the hydraulic system is not equipped with a master cylinder pressure sensor, or the hydraulic system is equipped with a master cylinder pressure sensor but the master cylinder pressure sensor cannot detect the master cylinder pressure due to a malfunction. In this case, it is determined that the master cylinder pressure sensor is invalid.

[0075] For the above sub-condition (2), when the main cylinder pressure is valid, if the main cylinder pressure exceeds the preset value range, it indicates that the hydraulic system is equipped with a main cylinder pressure sensor but the main cylinder pressure sensor has not collected the correct main cylinder pressure. At this time, it is determined that the main cylinder pressure sensor is faulty.

[0076] Optionally, the preset numerical range can be set according to the actual situation, and the present invention does not impose specific limitations on it.

[0077] In this step, the master cylinder pressure of the vehicle at the current moment is detected by using failure conditions, in order to determine whether the master cylinder pressure sensor has failed.

[0078] S104: When the main cylinder pressure is detected to meet the failure condition, the main cylinder pressure is replaced with the estimated main cylinder pressure and output.

[0079] In this step, if the main cylinder pressure of the vehicle at the current moment meets any of the sub-conditions (1)-(2) mentioned above, it indicates that the main cylinder pressure sensor has failed. At this time, the main cylinder pressure of the vehicle at the current moment is replaced with the estimated main cylinder pressure, and the replaced main cylinder pressure is output to ensure the accuracy of the main cylinder pressure.

[0080] In some embodiments of the present invention, referring to FIG1, after detecting the master cylinder pressure of the vehicle at the current moment according to the failure condition in step S103, the method further includes the following step S105.

[0081] S105: When the main cylinder pressure is detected to be insufficient to meet the failure condition, output the main cylinder pressure of the vehicle at the current moment.

[0082] In this step, if the main cylinder pressure of the vehicle at the current moment does not meet the sub-conditions (1)-(2) mentioned above, it means that the main cylinder pressure sensor has not failed. At this time, the main cylinder pressure detected by the main cylinder pressure sensor at the current moment is obtained and output.

[0083] In this invention, the pressure change rate inside the ABS is first used to control the vehicle state machine so that the vehicle enters the correction state from the first braking state. Then, considering various factors such as the vehicle's wheel characteristics, overall vehicle speed characteristics, pump pressure build-up action, and braking force, the master cylinder pressure in the vehicle's hydraulic system is accurately estimated and corrected. After that, the failure condition is used to determine whether the master cylinder pressure sensor has failed. If the master cylinder pressure sensor fails, the estimated master cylinder pressure (i.e., the estimated master cylinder pressure) is output, thereby ensuring the accuracy of the master cylinder pressure and guaranteeing the functional safety of the brake-by-wire system.

[0084] The implementation process of the vehicle state machine provided by the present invention will be further described below with reference to the accompanying drawings.

[0085] In some embodiments of the present invention, referring to FIG3, in step S101, the process of controlling the vehicle to enter the correction state from the first braking state according to the pressure change rate inside the anti-lock braking system may include, but is not limited to, the following steps S1011-1013.

[0086] S1011, compare the pressure change rate inside the anti-lock braking system with the first threshold, that is, determine whether the pressure change rate inside the ABS is greater than or equal to the first threshold; if yes, proceed to step S1012; if no, proceed to step S1013.

[0087] Optionally, the first threshold can be set according to the actual situation, and the present invention does not impose specific limitations on it.

[0088] In this step, the pressure change rate inside the ABS is compared with the first threshold, that is, it is determined whether the pressure change rate inside the ABS is greater than or equal to the first threshold. The purpose is to detect whether the pressure inside the ABS increases sharply within a certain period of time.

[0089] S1012, controls the vehicle to enter the correction state from the first braking state.

[0090] Specifically, when the pressure inside the ABS increases sharply within a certain period, the frequency of the pressure signal from the master cylinder pressure sensor also increases sharply. This leads to a significant error in the master cylinder pressure detected by the sensor. Therefore, it is necessary to control the vehicle to enter a correction state to correct the master cylinder pressure value detected by the sensor under these conditions. In this step, when the detected pressure change rate inside the ABS is greater than or equal to a first threshold, it indicates a sharp increase in pressure within the ABS within a certain period. At this point, the vehicle is switched from the first braking state to the correction state to correct the master cylinder pressure value.

[0091] S1013 controls the vehicle to maintain the first braking state, obtains the current master cylinder pressure of the vehicle and outputs it.

[0092] Specifically, under normal pressure increases within the ABS system over a certain period, the frequency of the pressure signal from the master cylinder pressure sensor will not increase sharply, and the error in the master cylinder pressure detected by the sensor is also small. Therefore, it is not necessary to correct the master cylinder pressure value detected by the sensor under these circumstances. In this step, when the detected pressure change rate within the ABS is less than the first threshold, it indicates that the pressure within the ABS system is increasing normally over a certain period. At this time, the vehicle is controlled to maintain the first braking state, and the master cylinder pressure detected by the master cylinder pressure sensor at the current moment is acquired and output.

[0093] In some embodiments of the present invention, referring to Figures 2 and 4, the master cylinder pressure processing method provided by the present invention may further include the following steps S201-S204.

[0094] S201, when the vehicle is in the first braking state, a first switching request is obtained, and the vehicle is controlled to switch from the first braking state to the second braking state according to the first switching request.

[0095] It should be noted that the first switching request is used to control the vehicle to switch from the first braking state to the second braking state. The second braking state represents the vehicle's state when ABS is off and EBD is on. Off ABS means the ABS function is inactive, and on EBD means the EBD function is active.

[0096] In this step, when the vehicle is in the first braking state, a first switching request is obtained, and the ABS is turned off and the EBD is turned on according to the first switching request, so that the vehicle can enter the second braking state from the first braking state.

[0097] Optionally, the first switching request is triggered by information such as the roughness of the road surface on which the vehicle is traveling, the engine drag torque of the front axle and the engine drag torque of the rear axle, the braking force (i.e., whether it is under-braking or over-braking), the vehicle acceleration, the activation status of the TCS (Traction Control System), the vehicle reference speed, the activation status of braking-related electronic devices, the acceleration of the wheels when the vehicle is fully loaded, wheel height jump information, wheel minimum acceleration, wheel hydraulic mode, wheel control mode, and wheel speed signal quality. The triggering of the first switching request is prior art, and this invention will not elaborate on it further.

[0098] S202, when the vehicle is in the second braking state, obtain the master cylinder pressure of the vehicle at the current moment, and detect the estimated master cylinder pressure, that is, detect whether there is an estimated master cylinder pressure; if yes, proceed to step S203; if no, proceed to step S204.

[0099] In this step, when the vehicle disables ABS and enables EBD, the vehicle will transition from the first braking state to the second braking state. After entering the second braking state, the master cylinder pressure detected by the master cylinder pressure sensor at the current moment is acquired, and the existence of an estimated master cylinder pressure is also detected. The aim is to obtain a more accurate master cylinder pressure based on the master cylinder pressure detected by the master cylinder pressure sensor at the current moment and the estimated master cylinder pressure obtained in the correction state.

[0100] S203, select the minimum value between the estimated master cylinder pressure and the current master cylinder pressure of the vehicle as the first update value, replace the current master cylinder pressure of the vehicle with the first update value and output it.

[0101] In this step, if the vehicle has entered a correction state before entering the second braking state, there is an estimated master cylinder pressure. When the estimated master cylinder pressure is detected, the minimum value between the estimated master cylinder pressure and the master cylinder pressure detected by the master cylinder pressure sensor at the current moment is selected as the first update value. Then, the value of the master cylinder pressure detected by the master cylinder pressure sensor at the current moment is replaced with the first update value and output, thereby improving the accuracy of the master cylinder pressure.

[0102] S204 directly outputs the main cylinder pressure of the vehicle at the current moment.

[0103] In this step, when it is detected that there is no master cylinder estimated pressure, the master cylinder pressure detected by the master cylinder pressure sensor at the current moment is directly output.

[0104] In some embodiments of the present invention, referring to Figures 2 and 5, the master cylinder pressure processing method provided by the present invention may further include the following steps S301-S302.

[0105] S301, when the vehicle is in the second braking state, obtain the second switching request.

[0106] S302, according to the second switching request, control the vehicle to switch from the second braking state to the first braking state.

[0107] It should be noted that the second switching request is used to control the vehicle to switch from the second braking state to the first braking state.

[0108] In the above steps, when the vehicle is in the second braking state, a second switching request is obtained, and EBD is deactivated and ABS is activated according to the second switching request, thereby causing the vehicle to enter the first braking state from the second braking state. It should be understood that after the vehicle enters the first braking state, step S101 can be performed.

[0109] Optionally, the second switching request can be triggered by the roughness of the road surface on which the vehicle is traveling, as well as information such as the front axle engine drag torque, rear axle engine drag torque, braking force, vehicle acceleration, TCS activation status, vehicle reference speed, activation status of braking-related electronic devices, wheel acceleration when the vehicle is fully loaded, wheel height jump information, wheel minimum acceleration, wheel hydraulic mode, wheel control mode, and wheel speed signal quality. The triggering of the second switching request is prior art, and this invention will not elaborate on it further.

[0110] In some embodiments of the present invention, referring to Figures 2 and 6, the master cylinder pressure processing method provided by the present invention may further include the following steps S401-S403.

[0111] S401: When the vehicle is in the first braking state, the second braking state, or the correction state, detect the pedal braking signal, that is, detect whether there is a pedal braking signal; if yes, proceed to S402; if no, proceed to S403.

[0112] In this step, if the driver presses the brake pedal, a pedal braking signal is present, and the vehicle is braking. At this time, the vehicle is in any of the following states: first braking state, second braking state, or correction state. If the driver does not press the brake pedal, there is no pedal braking signal, the vehicle stops braking, and the vehicle is in its initial state. Based on this, when the vehicle is in any of the following states: first braking state, second braking state, or correction state, the presence of a pedal braking signal is detected to determine whether to control the vehicle to exit any of the following states: first braking state, second braking state, or correction state.

[0113] S402, control the vehicle to maintain the first braking state, the second braking state, or the correction state, and return to step S401 to detect the pedal brake signal.

[0114] In this step, when the vehicle is in any of the first braking state, the second braking state, or the correction state, the detection of the pedal braking signal indicates that the driver is still pressing the brake pedal and the vehicle is braking. At this time, the vehicle is controlled to maintain the first braking state, the second braking state, or the correction state, and the process returns to step S401 to achieve cyclic detection.

[0115] S403 controls the vehicle to exit from the first braking state, the second braking state, or the correction state back to the initial state.

[0116] It should be noted that the initial state is used to characterize the vehicle's state when ABS and EBD are turned off.

[0117] In this step, when the vehicle is in any of the first braking state, second braking state, or correction state, if no pedal braking signal is detected, it means that the driver has released the brake pedal, the vehicle has stopped braking, and the vehicle is then controlled to exit the first braking state, second braking state, or correction state and enter the initial state.

[0118] In some embodiments of the present invention, referring to Figures 2 and 7, the master cylinder pressure processing method provided by the present invention may further include the following steps S501-S502.

[0119] S501 acquires and detects the rear axle pressure of the vehicle when it is in its initial state.

[0120] It should be noted that the rear axle pressure of a vehicle refers to the vertically downward pressure borne by the rear axle of the vehicle.

[0121] In this step, if the vehicle is in any of the first braking state, second braking state, or correction state and no pedal braking signal is detected, the vehicle will exit to the initial state. When the vehicle is in the initial state, the rear axle pressure of the vehicle is acquired and detected, specifically whether the rear axle pressure is less than a second threshold, in order to determine whether to control the vehicle to exit the initial state and enter the second braking state.

[0122] S502, when the rear axle pressure is detected to be less than the second threshold, the vehicle is controlled to maintain the initial state and return to the step of acquiring and detecting the rear axle pressure of the vehicle until the rear axle pressure is detected to be greater than or equal to the second threshold, then the vehicle is controlled to enter the second braking state from the initial state.

[0123] Optionally, the second threshold can be set according to the actual situation, and the present invention does not impose specific limitations on it.

[0124] For example, the second threshold is 20 bar.

[0125] In this step, when the detected rear axle pressure is less than the second threshold, it indicates that rear wheel lock-up and fishtailing will not occur in the future. At this time, the vehicle is kept in its initial state, and the process returns to step S501 to obtain and detect the rear axle pressure, thus performing a cyclical judgment. Conversely, when the detected rear axle pressure is greater than or equal to the second threshold, it indicates that rear wheel lock-up and fishtailing will occur in the future. At this time, the vehicle is controlled to activate EBD, causing it to transition from the initial state to the second braking state. While the vehicle is in the second braking state, the EBD function is activated, maintaining pressure on the rear wheels and increasing pressure on the front wheels, effectively preventing rear wheel lock-up and fishtailing.

[0126] In some embodiments of the present invention, referring to Figures 2 and 8, the master cylinder pressure processing method provided by the present invention may further include the following steps S601-S603.

[0127] S601, When the vehicle is in the initial state, check whether the master cylinder pressure sensor of the vehicle is initialized; if not, proceed to step S602; if yes, proceed to step S603.

[0128] In this step, if the vehicle is in any of the following states—first braking state, second braking state, or correction state—and no pedal braking signal is detected, the vehicle will exit to the initial state. When the vehicle is in the initial state, the initialization of the master cylinder pressure sensor is checked to determine whether the vehicle should exit the initial state and enter the correction state.

[0129] S602, control the vehicle to maintain the initial state, and return to step S601 to check whether the vehicle's master cylinder pressure sensor has been initialized.

[0130] In this step, the initialization process ensures that the master cylinder pressure sensor correctly detects, processes, and outputs signals. Initialization is performed on the master cylinder pressure sensor in the initial state. If the vehicle's master cylinder pressure sensor is detected as not initialized, it indicates that the sensor may be unable to perform its intended function due to incomplete initialization. In this case, the vehicle is kept in its initial state to continue initializing the master cylinder pressure sensor. Simultaneously, the system returns to step S601 to check whether the vehicle's master cylinder pressure sensor has been initialized, thus implementing a cyclical judgment.

[0131] S603 controls the vehicle to transition from its initial state to its corrective state.

[0132] In this step, when the initialization of the vehicle's master cylinder pressure sensor is detected, it indicates that the initialization of the master cylinder pressure sensor has been completed. At this time, the vehicle is controlled to exit the initial state and enter the correction state, so as to correct the master cylinder pressure detected by the master cylinder pressure sensor, thereby further improving the accuracy of the master cylinder pressure.

[0133] The principle of the vehicle state machine provided by the present invention will be explained below with reference to the accompanying drawings.

[0134] Referring to Figure 2, the vehicle state machine is equipped with a first braking state, a second braking state, a correction state, and an initial state. Specifically, the first braking state refers to the vehicle's state when ABS is activated and EBD is deactivated; in the first braking state, the vehicle is braking and the ABS function is activated. The second braking state refers to the vehicle's state when EBD is activated and ABS is deactivated; in the second braking state, the vehicle is braking and the EBD function is activated. The correction state refers to the vehicle's state when the pressure change rate inside the ABS exceeds a preset threshold, with ABS activated and EBD deactivated; in the correction state, the vehicle is braking and the ABS function is activated, and the master cylinder pressure is estimated and corrected. The initial state refers to the vehicle's state when ABS and EBD are deactivated; in the initial state, the vehicle has finished braking and the ABS and EBD functions are not activated.

[0135] It should be noted that the first braking state and the second braking state can be switched between each other, the second braking state and the initial state can be switched between each other, and the correction state and the initial state can also be switched between each other.

[0136] It is important to note that the first braking state can be switched to the correction state or the initial state, but the correction state or the initial state cannot return to the first braking state. In addition, the second braking state cannot be directly switched to the correction state. If it is necessary to switch from the second braking state to the correction state, the second braking state must first be switched to the initial state or the first braking state, and then the correction state must be entered from the initial state or the first braking state.

[0137] In this invention, the state transitions and triggering conditions between the first braking state, the second braking state, the correction state, and the initial state are as follows:

[0138] ① Switching from the first braking state to the correction state: The trigger condition is that the pressure change rate inside the ABS is detected to be greater than or equal to a first threshold, that is, the pressure inside the ABS increases sharply within a certain period of time; the output execution is to control the vehicle to continue to activate the ABS, that is, to continue to activate the ABS function, and to control the vehicle to switch from the first braking state to the correction state. In the correction state, the master cylinder pressure is estimated and corrected based on the vehicle's wheel information, under-braking information, over-braking information, and characteristic information as the vehicle's overall information.

[0139] ② Switching from the first braking state to the initial state: The trigger condition is that no pedal braking signal is detected, that is, the driver releases the brake pedal and the vehicle stops braking; the output execution is to control the vehicle to turn off ABS, that is, to deactivate the ABS function and control the vehicle to switch from the first braking state to the initial state.

[0140] ③ Switching from the first braking state to the second braking state: The trigger condition is obtaining the first switching request; the output execution is to control the vehicle to turn off ABS and enable EBD, that is, to deactivate the ABS function and activate the EBD function, and control the vehicle to switch from the first braking state to the second braking state.

[0141] ④ Switching from the second braking state to the first braking state: The trigger condition is obtaining a second switching request; the output execution is to control the vehicle to turn off EBD and enable ABS, that is, to deactivate the EBD function and activate the ABS function, and control the vehicle to switch from the second braking state to the first braking state.

[0142] ⑤ Switching from the second braking state to the initial state: The trigger condition is that no pedal braking signal is detected, that is, the driver releases the brake pedal and the vehicle ends braking; the output execution is to control the vehicle to turn off EBD, that is, to deactivate the EBD function and control the vehicle to switch from the second braking state to the initial state.

[0143] ⑥ Switching from the correction state to the initial state: The trigger condition is that no pedal braking signal is detected, that is, the driver releases the brake pedal and the vehicle stops braking; the output execution is to control the vehicle to turn off ABS, that is, to deactivate the ABS function and control the vehicle to switch from the first braking state to the initial state.

[0144] ⑦ Switch from the initial state to the second braking state: The trigger condition is that the rear axle pressure is detected to be greater than or equal to the second threshold, that is, the phenomenon of rear wheel lock-up and fishtailing will occur in the future time period; the output execution is to control the vehicle to enable EBD, that is, to activate the EBD function and control the vehicle to switch from the initial state to the second braking state.

[0145] ⑧ Switching from initial state to correction state: The trigger condition is the detection of the vehicle's master cylinder pressure sensor initialization; the output execution is to control the vehicle to enable ABS, that is, to activate the ABS function and control the vehicle to switch from the initial state to the correction state. In the correction state, the master cylinder pressure is estimated and corrected based on the vehicle's wheel information, under-braking information, over-braking information, and characteristic information as the vehicle's overall information.

[0146] The process of estimating and correcting the master cylinder pressure in the corrected state will be further described below with reference to the accompanying drawings.

[0147] In some embodiments of the present invention, the process of obtaining vehicle wheel information, under-braking information, over-braking information and characteristic information in step S102 may include, but is not limited to, the following steps S1021-S1024.

[0148] S1021, acquire the vehicle's front axle engine drag torque, rear axle engine drag torque, vehicle target pressure, vehicle speed, wheel speed signal quality, wheel control mode, wheel valve strategy, and wheel target braking torque as the vehicle's wheel information.

[0149] S1022, acquire the vehicle's overall acceleration, overall deceleration, average deceleration proportional coefficient, and hydraulic system characteristic parameters as the vehicle's characteristic information.

[0150] It should be noted that the characteristic parameters of the hydraulic system may include, but are not limited to, the pump action correction pressure, the sensed pressure, and the actual pressure of the hydraulic system. Among them, the pump action correction pressure is used to characterize the pressure value of the master cylinder when the pump is half open or fully open, the sensed pressure is used to characterize the pressure value of the master cylinder detected by the pressure sensor, and the actual pressure is used to characterize the actual pressure value of the master cylinder.

[0151] S1023, obtain the under-braking status set symbol and under-braking ratio coefficient of the vehicle, as well as the vehicle acceleration, vehicle acceleration change rate, master cylinder pressure, master cylinder pressure correction value, pump action change rate and braking force deviation value under under-braking conditions as under-braking information.

[0152] S1024, acquire the master cylinder pressure, master cylinder pressure correction value, master cylinder pressure change rate, vehicle speed, pump action change rate and counting time as over-braking information when the vehicle is under over-braking conditions.

[0153] It should be understood that steps S1021-S1024 can be executed in parallel (i.e., steps S1021-S1024 are executed simultaneously) or in sequence (i.e., steps S1021-S1024 are executed sequentially). This invention does not specifically limit the execution of these steps.

[0154] In some embodiments of the present invention, referring to FIG9, in step S102, the process of obtaining the estimated pressure of the vehicle's master cylinder based on the vehicle information may include, but is not limited to, the following steps S1025-S1027.

[0155] S1025 determines the first wheel enabling information based on the wheel speed signal quality, wheel control mode, wheel valve strategy, front axle engine drag torque, rear axle engine drag torque, and vehicle speed.

[0156] It should be noted that the first wheel enabling information includes either all four wheels being fault-free or at least one wheel having a fault.

[0157] In this step, wheel speed signal quality, wheel control mode, wheel valve strategy, front axle engine drag torque, rear axle engine drag torque, and vehicle speed are used to detect whether each wheel is in a normal state. When all wheels are detected to be in a normal state, it indicates that there are no faults in the wheel rims of all four wheels, and the first wheel enabling information is determined to be that all four wheels are fault-free. Conversely, when at least one wheel is detected to be in a abnormal state, it indicates that there is a fault in the wheel rim of at least one wheel, and the first wheel enabling information is determined to be that there is a fault in at least one wheel. The wheel rim refers to the wheel components, typically including the tire, rim, and hub.

[0158] S1026, determine the second wheel enabling information based on the vehicle target pressure and the wheel target braking torque.

[0159] It should be noted that the second wheel enabling information includes either detected braking torque or no detected braking torque. The braking torque can be the braking force generated by the driver pressing the brake pedal, or it can be an external braking force; this invention does not specifically limit its application.

[0160] In this step, the presence of braking torque is detected using the target pressure of the entire vehicle and the target braking torque of each wheel. When braking torque is detected, it means that braking torque is being applied to the wheel ends of all four wheels, and the second wheel enable signal is determined to indicate that braking torque has been detected. Conversely, when no braking torque is detected, it means that no braking torque is being applied to the wheel end of any of the wheels, and the second wheel enable signal is determined to indicate that braking torque has not been detected.

[0161] It should be understood that steps S1025 and S1026 can be executed in parallel (i.e., steps S1025 and S1026 are executed simultaneously) or sequentially (i.e., step S1025 is executed first, followed by step S1026, or step S1026 is executed first, followed by step S1025).

[0162] S1027, when the first wheel enabling information is that all four wheels are fault-free and the second wheel enabling information is that braking torque is detected, the estimated pressure of the vehicle's master cylinder is obtained based on the under-braking information, over-braking information and characteristic information.

[0163] In this step, if and only if the first wheel enabling information is that all four wheels are fault-free and the second wheel enabling information is that braking torque is detected, the master cylinder pressure is estimated and corrected using the insufficient braking information, over-braking information and characteristic information, thereby obtaining the estimated value of the vehicle's master cylinder pressure, i.e., the estimated master cylinder pressure.

[0164] In some embodiments of the present invention, referring to FIG10, in step S1027, the process of obtaining the estimated pressure of the vehicle's master cylinder based on the under-braking information, over-braking information and characteristic information may include, but is not limited to, the following steps S01-S09.

[0165] S01, initialize the master cylinder correction pressure, the master cylinder pressure correction value under over-braking conditions, and the under-braking state locator to zero.

[0166] In this step, before estimating and correcting the master cylinder pressure, the master cylinder correction pressure, the master cylinder pressure correction value under over-braking conditions, and the under-braking state setpoint are initialized to ensure the accuracy of related calculations in subsequent steps. Specifically, the master cylinder correction pressure, the master cylinder pressure correction value under over-braking conditions, and the under-braking state setpoint are set to 0.

[0167] S02, when the vehicle acceleration is greater than or equal to the vehicle acceleration under under-braking conditions, select the maximum value between zero and the master cylinder pressure under under-braking conditions as the second update value, and replace the master cylinder pressure under under-braking conditions with the second update value.

[0168] In this step, it is determined whether the overall vehicle acceleration is greater than or equal to the overall vehicle acceleration under under-braking conditions. This aims to determine if there is a difference between the overall vehicle acceleration and the overall vehicle acceleration under under-braking conditions. When the overall vehicle acceleration is greater than or equal to the overall vehicle acceleration under under-braking conditions, it indicates that there is a difference between the overall vehicle acceleration and the overall vehicle acceleration under under-braking conditions. In this case, it is necessary to determine the master cylinder pressure under under-braking conditions.

[0169] Specifically, when the master cylinder pressure sensor is functioning correctly and the master cylinder pressure under under-braking conditions is non-negative, the master cylinder pressure under under-braking conditions is considered normal. However, when the master cylinder pressure sensor fails and / or the master cylinder pressure under under-braking conditions is negative, the master cylinder pressure under under-braking conditions is considered invalid, where the invalid value is less than 0. It should be understood that an invalid master cylinder pressure under under-braking conditions will affect the calculations of subsequent steps. Therefore, this step selects the maximum value between 0 and the master cylinder pressure under under-braking conditions as the second update value, and sets the master cylinder pressure under under-braking conditions equal to the second update value. This ensures that when the master cylinder pressure under under-braking conditions is invalid, it is assigned a value of 0, and when it is normal, it remains at a normal value, thus ensuring the normal operation of subsequent steps.

[0170] More specifically, the above calculation process is shown in the following formula: F1 = max(0, f1);

[0171] In the formula, F1 represents the second updated value, f1 represents the master cylinder pressure under insufficient braking conditions before the update, and max(·) represents the operation of taking the maximum value.

[0172] After determining the master cylinder pressure under insufficient braking conditions, it is determined whether the vehicle deceleration is greater than or equal to the driver's braking deceleration, in order to detect whether the vehicle sends commands related to insufficient braking conditions.

[0173] S03, when the vehicle deceleration is greater than or equal to the driver's braking deceleration, calculate the third update value based on the under-braking ratio coefficient, the deviation value of the vehicle deceleration, the average deceleration ratio coefficient, and the master cylinder pressure and master cylinder pressure correction value under the under-braking condition, and replace the master cylinder pressure correction value under the under-braking condition with the third update value.

[0174] In this step, when the vehicle deceleration is greater than or equal to the driver's braking deceleration, it indicates that the vehicle can reach the preset deceleration when the driver presses the brake pedal, and the vehicle has not sent any commands related to under-braking conditions. At this time, based on the under-braking ratio coefficient, the deviation value of the vehicle deceleration, the average deceleration ratio coefficient, and the master cylinder pressure and master cylinder pressure correction value under under-braking conditions, a third update value is calculated, and the master cylinder pressure correction value under under-braking conditions is set equal to the third update value, thereby determining the master cylinder pressure correction value under under-braking conditions. After determining the master cylinder pressure correction value under under-braking conditions, it is determined whether the rate of change of vehicle acceleration under under-braking conditions is greater than 0, and whether the actual pressure is less than the difference between the sensed pressure and the braking force deviation value, in order to determine whether to retain the master cylinder pressure correction value under under-braking conditions.

[0175] Furthermore, the calculation process for the third update value may include, but is not limited to, the following steps.

[0176] First, the product of the master cylinder pressure under under-braking conditions and the under-braking ratio coefficient is calculated as the first product, and the product of the deviation value of the vehicle deceleration and the average deceleration ratio coefficient is calculated as the second product. Then, the difference between the master cylinder pressure correction value under under-braking conditions and the first product is calculated as the first value. Finally, the sum of the first value and the second product is calculated as the third update value.

[0177] Furthermore, after calculating the third updated value, the master cylinder pressure correction value under insufficient braking conditions is set equal to the third updated value. The above calculation process satisfies the following formula:

[0178] In the formula, This indicates the third updated value. This represents the master cylinder pressure correction value under under-braking conditions before the update. F1 represents the master cylinder pressure under under-braking conditions, and 'a' represents the under-braking proportional coefficient. 'b' represents the deviation in deceleration, and 'b' represents the proportionality coefficient of the average deceleration.

[0179] S04. When the rate of change of vehicle acceleration under insufficient braking conditions is greater than zero and / or the actual pressure is less than the difference between the sensing pressure and the braking force deviation value, the road surface on which the vehicle is traveling is identified.

[0180] In this step, when the vehicle meets at least one of sub-conditions (3)-(4), the master cylinder pressure correction value calculated in the previous step under the under-braking condition is retained, and the road surface on which the vehicle is traveling is identified, in order to detect whether the vehicle is traveling on a rough road surface, so as to combine road surface factors to determine the estimated value of the master cylinder pressure. Among them, sub-condition (3) means that the rate of change of the vehicle acceleration under the under-braking condition is greater than zero, and sub-condition (4) means that the actual pressure is less than the difference between the sensing pressure and the braking force deviation value.

[0181] S05, when it is identified that the road surface on which the vehicle is traveling is a non-rough road surface, and the vehicle speed under over-braking conditions is greater than the pump action change rate under over-braking conditions and / or the vehicle acceleration change rate under under-braking conditions is less than the pump action change rate under under-braking conditions, the peak value of the vehicle's master cylinder pressure at the current moment is detected.

[0182] In this step, when it is detected that the road surface on which the vehicle is traveling is not rough, it is determined whether the vehicle speed under over-braking conditions is greater than the pump action change rate under over-braking conditions, and whether the vehicle acceleration change rate under under-braking conditions is less than the pump action change rate under under-braking conditions. The purpose is to compare the performance of the vehicle with that of the pump to determine whether there is a difference between the performance of the vehicle and the performance of the pump. When the vehicle meets at least one of the sub-conditions (5)-(6), it indicates that there is a difference between the performance of the vehicle and the performance of the pump, and the pump may perform a pressure build-up action. At this time, it is detected whether the master cylinder pressure has a peak value, in order to further detect whether the pump performs a pressure build-up action, so as to combine the factors of the pump pressure build-up action to determine the estimated value of the master cylinder pressure. Among them, sub-condition (5) means that the vehicle speed under over-braking conditions is greater than the pump action change rate under over-braking conditions, and sub-condition (6) means that the vehicle acceleration change rate under under-braking conditions is less than the pump action change rate under under-braking conditions.

[0183] S06, when no peak value of the vehicle's master cylinder pressure is detected at the current moment, calculate the fourth update value based on the master cylinder correction pressure, pump action correction pressure, master cylinder pressure correction value under over-braking conditions and master cylinder pressure correction value under under-braking conditions, and replace the master cylinder correction pressure with the fourth update value.

[0184] In this step, if the peak value of the master cylinder pressure at the current moment is not detected, it means that the pump has not performed a pressure build-up action. At this time, the fourth update value is calculated based on the master cylinder correction pressure, the pump action correction pressure, the master cylinder pressure correction value under over-braking conditions, and the master cylinder pressure correction value under under-braking conditions. The master cylinder correction pressure is then set to equal the fourth update value to determine the master cylinder correction pressure.

[0185] Furthermore, the calculation process for the fourth update value may include, but is not limited to, the following steps.

[0186] First, the maximum value between the master cylinder pressure correction value under over-braking conditions and the pump action correction pressure is selected as the second value; then, the minimum value between the master cylinder pressure correction value under 0 and under-braking conditions is selected as the third value; finally, the sum of the master cylinder correction pressure, the second value, and the third value is calculated as the fourth update value.

[0187] Furthermore, after calculating the fourth update value, the master cylinder correction pressure is set to equal the fourth update value. The above calculation process is shown in the following formula:

[0188] In the formula, This indicates the fourth updated value. This indicates the master cylinder correction pressure before the update. This indicates the master cylinder pressure correction value under over-braking conditions. This indicates the pressure correction for pump operation, and min(·) indicates the operation of taking the minimum value.

[0189] S07, calculate the difference between the master cylinder correction pressure at the current moment and the master cylinder correction pressure at the previous moment as the deviation value of the master cylinder correction pressure, and according to the zeroing condition, detect the deviation value of the master cylinder correction pressure, the master cylinder pressure correction value under the under-braking condition, and the counting time under the over-braking condition.

[0190] It should be noted that the zeroing conditions may include, but are not limited to, a master cylinder pressure correction value greater than 0 under under-braking conditions, a counting time equal to 0 under over-braking conditions, and a master cylinder correction pressure deviation value equal to 0.

[0191] In this step, after calculating the master cylinder correction pressure, firstly, the difference between the master cylinder correction pressure at the current moment and the master cylinder correction pressure at the previous moment is calculated, and this difference is used as the deviation value of the master cylinder correction pressure; then, it is determined whether the deviation value of the master cylinder correction pressure, the master cylinder pressure correction value under under-braking conditions, and the counting time under over-braking conditions meet the zeroing condition, in order to determine whether to retain the calculated master cylinder correction pressure.

[0192] S08, when the deviation value of the master cylinder correction pressure, the master cylinder pressure correction value under insufficient braking condition, and the counting time under over-braking condition all fail to meet the zeroing condition, update the master cylinder correction pressure, obtain the updated master cylinder correction pressure, and acquire the initial value of the master cylinder correction pressure.

[0193] In this step, if the deviation value of the master cylinder correction pressure, the master cylinder pressure correction value under under-braking conditions, and the counting time under over-braking conditions all fail to meet the zeroing condition (i.e., the master cylinder pressure correction value under under-braking conditions is less than or equal to 0, the counting time under over-braking conditions is not equal to 0, and the deviation value of the master cylinder correction pressure is not equal to 0), then the master cylinder correction pressure calculated in the previous step is retained, and the master cylinder correction pressure is updated to obtain the updated master cylinder correction pressure. Next, the initial value of the master cylinder correction pressure is obtained to determine whether the initial value is greater than the master cylinder pressure correction value under under-braking conditions, thereby determining whether the vehicle is under-braking.

[0194] Furthermore, the update process for master cylinder correction pressure may include, but is not limited to, the following steps.

[0195] First, select the maximum value between zero and the master cylinder correction pressure as the fourth value; then, calculate the sum of the fourth value and the master cylinder correction pressure as the updated master cylinder correction pressure.

[0196] Furthermore, the update process for the master cylinder correction pressure is shown in the following formula:

[0197] In the formula, F represents the updated master cylinder correction pressure.

[0198] S09, when the initial value of the master cylinder correction pressure is greater than the master cylinder pressure correction value under the under-braking condition, update the under-braking state set symbol and output it, and at the same time output the updated master cylinder correction pressure as the master cylinder estimated pressure.

[0199] In this step, when the initial value of the master cylinder correction pressure is greater than the master cylinder pressure correction value under under-braking conditions, it is determined that the vehicle is under-braking. At this time, the value of the under-braking set symbol is modified to 1 and output, and the updated master cylinder correction pressure obtained in the previous step is output as the master cylinder estimated pressure.

[0200] Secondly, the implementation of the master cylinder pressure processing device provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0201] Referring to Figure 11, which is a structural diagram of a master cylinder pressure processing device provided by the present invention, the device mainly includes:

[0202] The state machine control module 100 is used to acquire the pressure change rate inside the vehicle's anti-lock braking system when the vehicle is in the first braking state, and control the vehicle to enter the correction state from the first braking state according to the pressure change rate inside the anti-lock braking system.

[0203] The pressure estimation module 200 is used to acquire the vehicle's wheel information, under-braking information, over-braking information and characteristic information as the vehicle's overall information when the vehicle is in a correction state, and to obtain the estimated pressure of the vehicle's master cylinder based on the overall vehicle information.

[0204] The detection module 300 is used to detect the master cylinder pressure of the vehicle at the current moment according to the failure condition; and when the master cylinder pressure is detected to meet the failure condition, the master cylinder pressure is replaced with the estimated master cylinder pressure and output.

[0205] The content of the above method embodiments is applicable to the device embodiments. The specific functions implemented by the device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0206] In addition, the present invention also provides a redundant braking system, which processes the pressure of the master cylinder using the master cylinder pressure processing method described above.

[0207] Similarly, the content of the above method embodiments is applicable to this system embodiment. The specific functions implemented in this system embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0208] Finally, the present invention also provides a vehicle including the master cylinder pressure handling device and / or the electronic device described above.

[0209] Understandably, the vehicle can be a private car, such as a sedan, sport utility vehicle (SUV), multi-purpose vehicle (MPV), or pickup truck, or a commercial vehicle, such as a van, bus, small truck, or large trailer, or a gasoline vehicle or a new energy vehicle such as a hybrid or pure electric vehicle.

[0210] Similarly, the content of the above method embodiments is applicable to this vehicle embodiment. The specific functions implemented in this vehicle embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0211] The implementation principles of the master cylinder pressure processing method, device, redundant braking system, and vehicle provided by this invention will be explained below.

[0212] Referring to Figure 2, the vehicle state machine is equipped with a first braking state, a second braking state, a correction state, and an initial state. Specifically, the first braking state refers to the vehicle's state when ABS is activated and EBD is deactivated; in the first braking state, the vehicle is braking and the ABS function is activated. The second braking state refers to the vehicle's state when EBD is activated and ABS is deactivated; in the second braking state, the vehicle is braking and the EBD function is activated. The correction state refers to the vehicle's state when the pressure change rate inside the ABS exceeds a preset threshold, with ABS activated and EBD deactivated; in the correction state, the vehicle is braking and the ABS function is activated, and the master cylinder pressure is estimated and corrected. The initial state refers to the vehicle's state when ABS and EBD are deactivated; in the initial state, the vehicle has finished braking and the ABS and EBD functions are not activated.

[0213] Based on this, referring to Figure 12, the implementation principle of the present invention for processing the pressure of the master cylinder of the hydraulic system is as follows:

[0214] S1: Detect the vehicle's current state. If the vehicle is in the first braking state, proceed to step S2; if the vehicle is in the second braking state, proceed to step S3; if the vehicle is in the initial state, proceed to step S4; if the vehicle is in the correction state, proceed to step S5.

[0215] S2: Detect whether the pressure change rate inside the ABS is greater than or equal to the first threshold, detect whether the first switching request is obtained, and detect whether braking has ended;

[0216] If a first switching request is detected, control the vehicle to switch from the first braking state to the second braking state, and proceed to step S3;

[0217] If braking is detected to have ended, control the vehicle to return from the first braking state to the initial state and proceed to step S4.

[0218] If the pressure change rate inside the ABS is greater than or equal to the first threshold, control the vehicle to enter the correction state from the first braking state and proceed to step S5.

[0219] If no first switching request is detected, and the pressure change rate inside the ABS is less than the first threshold, and the braking has not ended, the master cylinder pressure detected by the master cylinder pressure sensor is output.

[0220] S3: Detect whether a second handover request has been received, and detect whether braking has ended;

[0221] If a second switching request is detected, control the vehicle to switch from the second braking state to the first braking state, and proceed to step S2;

[0222] If braking is detected to have ended, control the vehicle to return from the second braking state to the initial state and proceed to step S4.

[0223] If no second switching request is detected and braking has not ended, determine whether there is master cylinder estimated pressure; if yes, select the minimum value between the master cylinder pressure detected by the master cylinder pressure sensor and the master cylinder estimated pressure as the output value of master cylinder pressure; if no, output the master cylinder pressure detected by the master cylinder pressure sensor.

[0224] S4: Detect whether the master cylinder pressure sensor is initialized and whether the rear axle pressure of the vehicle is greater than or equal to the second threshold.

[0225] If the rear axle pressure of the vehicle is greater than or equal to the second threshold, control the vehicle to enter the second braking state from the initial state and proceed to step S3;

[0226] If the master cylinder pressure sensor is initialized, control the vehicle to enter the correction state from the initial state and proceed to step S5.

[0227] S5: Based on the vehicle's wheel information, characteristic information, under-braking information, and over-braking information, obtain the estimated pressure of the vehicle's master cylinder.

[0228] Specifically, firstly, the system acquires the vehicle's front axle engine drag torque, rear axle engine drag torque, overall vehicle target pressure, vehicle speed, wheel speed signal quality, wheel control mode, wheel valve strategy, and wheel target braking torque. Using the wheel speed signal quality, wheel control mode, wheel valve strategy, front axle engine drag torque, rear axle engine drag torque, and vehicle speed, it checks whether each wheel is fault-free. Simultaneously, it uses the overall vehicle target pressure and wheel target braking torque to detect the presence of braking torque. Only when all four wheels are fault-free and braking torque is detected, the master cylinder pressure is estimated and corrected using under-braking information, over-braking information, and characteristic information.

[0229] While acquiring wheel information, the system also acquires vehicle acceleration, deceleration, average deceleration ratio, and hydraulic system characteristic parameters as vehicle characteristic information. It acquires under-braking status indicators and under-braking ratios, as well as vehicle acceleration, rate of change of acceleration, master cylinder pressure, master cylinder pressure correction value, pump action rate of change, and braking force deviation under under-braking conditions as under-braking information. Furthermore, it acquires master cylinder pressure, master cylinder pressure correction value, master cylinder pressure rate of change, vehicle speed, pump action rate of change, and counting time under over-braking conditions as over-braking information. All of this information will be used in the estimation and correction of master cylinder pressure.

[0230] Then, the master cylinder pressure is estimated and corrected, and the specific process is as follows:

[0231] Set the master cylinder correction pressure, the master cylinder pressure correction value under over-braking conditions, and the under-braking state locator to 0, and determine whether the vehicle acceleration is greater than or equal to the vehicle acceleration under under-braking conditions.

[0232] If the vehicle acceleration is greater than or equal to the vehicle acceleration under under-braking conditions, the second update value is determined by the formula F1 = max(0, f1), and the master cylinder pressure under under-braking conditions is set to equal the second update value. In this formula, F1 represents the second update value, f1 represents the master cylinder pressure under under-braking conditions before the update, and max(·) represents the operation of taking the maximum value.

[0233] If the vehicle deceleration is greater than or equal to the driver's braking deceleration, the formula can be used to determine the deceleration. Determine the third update value, setting the master cylinder pressure correction value under insufficient braking conditions equal to the third update value. In this formula... This indicates the third updated value. This represents the master cylinder pressure correction value under under-braking conditions before the update. F1 represents the master cylinder pressure under under-braking conditions, and 'a' represents the under-braking proportional coefficient. 'b' represents the deviation in deceleration, and 'b' represents the average deceleration proportionality coefficient. Then, determine whether the following conditions are met for the rate of change of vehicle acceleration under under-braking conditions, actual pressure, road surface traveled by the vehicle, vehicle speed under over-braking conditions, and the rate of change of vehicle acceleration under under-braking conditions:

[0234] The vehicle acceleration change rate under under-braking conditions is greater than zero and / or the actual pressure is less than the difference between the sensed pressure and the braking force deviation; the road surface the vehicle is traveling on is not rough; the vehicle speed under over-braking conditions is greater than the pump action change rate under over-braking conditions and / or the vehicle acceleration change rate under under-braking conditions is less than the pump action change rate under under-braking conditions; no peak value of the vehicle's master cylinder pressure at the current moment was detected.

[0235] If the rate of change of vehicle acceleration under under-braking conditions, actual pressure, road surface, vehicle speed under over-braking conditions, and rate of change of vehicle acceleration under under-braking conditions all satisfy the above conditions, then the formula can be used to apply the formula. To determine the fourth update value, set the master cylinder correction pressure equal to the fourth update value in this formula. This indicates the fourth updated value. This indicates the master cylinder correction pressure before the update. This indicates the master cylinder pressure correction value under over-braking conditions. This represents the pump's pressure correction, and min(·) indicates the operation of taking the minimum value. Then, the difference between the current master cylinder correction pressure and the previous master cylinder correction pressure is calculated as the deviation value of the master cylinder correction pressure. Finally, it is determined whether the deviation value of the master cylinder correction pressure, the master cylinder pressure correction value under under-braking conditions, and the counting time under over-braking conditions satisfy the following conditions:

[0236] The master cylinder pressure correction value is greater than 0 under insufficient braking conditions; the counting time is equal to 0 under over-braking conditions; and the deviation value of the master cylinder correction pressure is equal to 0.

[0237] If the deviation value of the master cylinder correction pressure, the master cylinder pressure correction value under insufficient braking conditions, and the counting time under over-braking conditions all fail to meet the above conditions, then the formula is used. Update the master cylinder correction pressure to obtain the updated master cylinder correction pressure F. Then, obtain the initial value of the master cylinder correction pressure and determine whether the initial value of the master cylinder correction pressure is greater than the master cylinder pressure correction value under insufficient braking conditions.

[0238] If the initial value of the master cylinder correction pressure is greater than the master cylinder pressure correction value under under-braking conditions, it is determined that the vehicle is under-braking. At this time, the value of the under-braking set symbol is modified to 1 and output, and the updated master cylinder correction pressure obtained in the previous steps is output as the master cylinder estimated pressure.

[0239] Finally, check if the master cylinder pressure sensor is faulty; if so, replace the current master cylinder pressure with the estimated master cylinder pressure and output the replaced master cylinder pressure; if not, output the master cylinder pressure detected by the master cylinder pressure sensor at the current moment.

[0240] Specifically, it determines whether the current master cylinder pressure of the vehicle is invalid or valid but exceeds a preset value range. If either the current master cylinder pressure is invalid or valid but exceeds the preset value range, the master cylinder pressure sensor is determined to be faulty, and the current master cylinder pressure is replaced with the estimated master cylinder pressure, which is then output. Otherwise, the master cylinder pressure sensor is determined to be valid, and the master cylinder pressure detected by the sensor is directly output.

[0241] In summary, this invention utilizes the vehicle state machine and various factors such as vehicle wheel characteristics, overall vehicle speed characteristics, pump pressure build-up, and braking force to accurately estimate and correct the master cylinder pressure in the vehicle's hydraulic system. This not only effectively improves the accuracy of the master cylinder pressure but also ensures the output of the master cylinder pressure value even if the master cylinder pressure sensor fails, guaranteeing the functional execution of the brake-by-wire system. Especially in redundant braking systems, it achieves better redundant braking effects, further enhancing driving safety.

[0242] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0243] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. A master cylinder pressure processing method characterized by, Includes the following steps: When the vehicle is in the first braking state, the pressure change rate inside the vehicle's anti-lock braking system is acquired, and the vehicle is controlled to enter the correction state from the first braking state based on the pressure change rate inside the anti-lock braking system; wherein, the first braking state is used to characterize the state of the vehicle when the anti-lock braking system is activated and the electronic brake-force distribution system is deactivated, and the pressure change rate is used to characterize the amount of pressure change inside the anti-lock braking system per unit time. When the vehicle is in the correction state, the wheel information, under-braking information, over-braking information and characteristic information of the vehicle are acquired as the whole vehicle information, and the estimated pressure of the master cylinder of the vehicle is obtained based on the whole vehicle information. Based on the failure condition, the master cylinder pressure of the vehicle at the current moment is detected; wherein, the failure condition includes either the master cylinder pressure being invalid or the master cylinder pressure exceeding a preset value range when the master cylinder pressure is valid; When the master cylinder pressure is detected to meet the failure condition, the master cylinder pressure is replaced with the estimated master cylinder pressure and output.

2. The master cylinder pressure processing method according to claim 1, characterized by, The step of controlling the vehicle to enter the corrective state from the first braking state based on the pressure change rate inside the anti-lock braking system includes: Compare the rate of pressure change inside the anti-lock braking system with a first threshold; When the rate of pressure change inside the anti-lock braking system is greater than or equal to a first threshold, the vehicle is controlled to enter the correction state from the first braking state. When the pressure change rate inside the anti-lock braking system is less than a first threshold, the vehicle is controlled to maintain the first braking state, and the master cylinder pressure of the vehicle at the current moment is obtained and output.

3. The master cylinder pressure processing method according to claim 1, characterized by, The method further includes the following steps: When the master cylinder pressure is detected to be not in compliance with the failure condition, the master cylinder pressure of the vehicle at the current moment is output.

4. The master cylinder pressure processing method according to claim 1, characterized by, The method further includes the following steps: When the vehicle is in the first braking state, a first switching request is obtained; According to the first switching request, the vehicle is controlled to enter a second braking state from the first braking state; wherein, the second braking state is used to characterize the state of the vehicle when the anti-lock braking system is turned off and the electronic brake force distribution system is turned on; When the vehicle is in the second braking state, the master cylinder pressure of the vehicle at the current moment is obtained, and the estimated pressure of the master cylinder is detected; When the estimated master cylinder pressure is detected, the minimum value between the estimated master cylinder pressure and the current master cylinder pressure of the vehicle is selected as the first update value, and the current master cylinder pressure of the vehicle is replaced with the first update value and output. If the estimated master cylinder pressure is not detected, the current master cylinder pressure of the vehicle is directly output.

5. The master cylinder pressure processing method according to claim 4, characterized by, The method further includes the following steps: When the vehicle is in the second braking state, a second switching request is obtained; According to the second switching request, the vehicle is controlled to switch from the second braking state to the first braking state.

6. The master cylinder pressure processing method according to claim 4, characterized by, The method further includes the following steps: When the vehicle is in the first braking state, the second braking state, or the correction state, the pedal braking signal is detected; When the pedal braking signal is detected, the vehicle is controlled to maintain the first braking state, the second braking state, or the correction state, and returns to the step of detecting the pedal braking signal until the pedal braking signal is no longer detected. Then, the vehicle is controlled to exit from the first braking state, the second braking state, or the correction state to the initial state. The initial state is used to characterize the state of the vehicle when the anti-lock braking system and the electronic brake force distribution system are turned off.

7. The master cylinder pressure processing method according to claim 6, characterized by, The method further includes the following steps: When the vehicle is in the initial state, the rear axle pressure of the vehicle is acquired and detected; When the rear axle pressure is detected to be less than the second threshold, the vehicle is controlled to maintain the initial state and return to the step of acquiring and detecting the rear axle pressure of the vehicle until the rear axle pressure is detected to be greater than or equal to the second threshold, at which point the vehicle is controlled to enter the second braking state from the initial state.

8. The master cylinder pressure processing method according to claim 6, characterized by, The method further includes the following steps: When the vehicle is in the initial state, it is detected whether the master cylinder pressure sensor of the vehicle is initialized; When it is detected that the master cylinder pressure sensor of the vehicle is not initialized, the vehicle is controlled to maintain the initial state and return to the step of detecting whether the master cylinder pressure sensor of the vehicle is initialized, until the master cylinder pressure sensor of the vehicle is detected to be initialized, and the vehicle is controlled to enter the correction state from the initial state.

9. The master cylinder pressure processing method according to claim 1, characterized by, The acquisition of the vehicle's wheel information, under-braking information, over-braking information, and characteristic information includes: The front axle engine drag torque, rear axle engine drag torque, vehicle target pressure, vehicle speed, wheel speed signal quality, wheel control mode, wheel valve strategy, and wheel target braking torque of the vehicle are acquired as wheel information of the vehicle. The vehicle's overall acceleration, overall deceleration, average deceleration proportional coefficient, and hydraulic system characteristic parameters are obtained as the vehicle's characteristic information. The hydraulic system characteristic parameters include the pump action correction pressure, the sensing pressure, and the actual pressure of the hydraulic system. The pump action correction pressure is used to characterize the pressure value of the master cylinder when the pump in the hydraulic system is half open or fully open. The sensing pressure is used to characterize the pressure value of the master cylinder detected by the pressure sensor. The actual pressure is used to characterize the actual pressure value of the master cylinder. The under-braking status set symbol and under-braking ratio coefficient of the vehicle, as well as the vehicle acceleration, vehicle acceleration change rate, master cylinder pressure, master cylinder pressure correction value, pump action change rate and braking force deviation value under the under-braking condition are obtained as the under-braking information. The under-braking condition is used to characterize the braking condition of the vehicle when the deceleration of the whole vehicle is less than the braking deceleration of the driver; the pump action change rate is used to characterize the pressure build-up frequency of the pump in the hydraulic system; and the braking force deviation value is used to characterize the braking force deviation value when the vehicle is stopped. The master cylinder pressure, master cylinder pressure correction value, master cylinder pressure change rate, vehicle speed, pump action change rate, and counting time under over-braking conditions are obtained as the over-braking information. The over-braking condition is used to characterize the braking condition of the vehicle when the deceleration of the whole vehicle is greater than the braking deceleration of the driver, and the counting time is used to characterize the duration of the over-braking condition.

10. The master cylinder pressure processing method according to claim 9, characterized by, The step of obtaining the estimated pressure of the main cylinder of the vehicle based on the vehicle information includes: The first wheel enabling information is determined based on the wheel speed signal quality, the wheel control mode, the wheel valve strategy, the front axle engine drag torque, the rear axle engine drag torque, and the vehicle speed. The second wheel enabling information is determined based on the target pressure of the whole vehicle and the target braking torque of the wheel; When the first wheel enabling information indicates that all four wheels are fault-free and the second wheel enabling information indicates that braking torque is detected, the estimated pressure of the vehicle's master cylinder is obtained based on the under-braking information, the over-braking information, and the characteristic information.

11. The master cylinder pressure processing method according to claim 10, characterized by, The step of obtaining the estimated master cylinder pressure of the vehicle based on the under-braking information, the over-braking information, and the characteristic information includes: Initialize the master cylinder correction pressure, the master cylinder pressure correction value under over-braking conditions, and the under-braking state locator to zero; When the vehicle acceleration is greater than or equal to the vehicle acceleration under under-braking conditions, the maximum value between zero and the master cylinder pressure under under-braking conditions is selected as the second update value, and the master cylinder pressure under under-braking conditions is replaced with the second update value. When the vehicle deceleration is greater than or equal to the driver's braking deceleration, a third update value is calculated based on the under-braking ratio coefficient, the deviation value of the vehicle deceleration, the average deceleration ratio coefficient, the master cylinder pressure under the under-braking condition, and the master cylinder pressure correction value, and the master cylinder pressure correction value under the under-braking condition is replaced with the third update value. When the rate of change of vehicle acceleration under insufficient braking conditions is greater than zero and / or the actual pressure is less than the difference between the sensed pressure and the braking force deviation value, the road surface on which the vehicle is traveling is identified. When it is identified that the road surface on which the vehicle is traveling is a non-rough road surface, and the vehicle speed under over-braking conditions is greater than the pump action change rate under over-braking conditions and / or the vehicle acceleration change rate under under-braking conditions is less than the pump action change rate under under-braking conditions, the peak value of the master cylinder pressure of the vehicle at the current moment is detected. When no peak value of the master cylinder pressure of the vehicle at the current moment is detected, a fourth update value is calculated based on the master cylinder correction pressure, the pump action correction pressure, the master cylinder pressure correction value under over-braking conditions and the master cylinder pressure correction value under under-braking conditions, and the master cylinder correction pressure is replaced with the fourth update value. The difference between the master cylinder correction pressure at the current moment and the master cylinder correction pressure at the previous moment is calculated as the deviation value of the master cylinder correction pressure. Based on the zeroing condition, the deviation value of the master cylinder correction pressure, the master cylinder pressure correction value under under-braking conditions, and the counting time under over-braking conditions are detected. The zeroing condition includes the master cylinder pressure correction value under under-braking conditions being greater than zero, the counting time under over-braking conditions being equal to zero, and the deviation value of the master cylinder correction pressure being equal to zero. When the deviation value of the master cylinder correction pressure, the master cylinder pressure correction value under insufficient braking condition, and the counting time under over-braking condition are all found to be inconsistent with the zeroing condition, the master cylinder correction pressure is updated to obtain the updated master cylinder correction pressure, and the initial value of the master cylinder correction pressure is obtained. When the initial value of the master cylinder correction pressure is greater than the master cylinder pressure correction value under under-braking conditions, the under-braking state set symbol is updated and output, and the updated master cylinder correction pressure is output as the estimated master cylinder pressure.

12. The master cylinder pressure processing method according to claim 11, characterized by, The calculation of the third update value based on the underbraking ratio coefficient, the deviation value of the vehicle deceleration, the average deceleration ratio coefficient, and the master cylinder pressure and master cylinder pressure correction value under underbraking conditions includes: The product of the master cylinder pressure under the under-braking condition and the under-braking proportional coefficient is calculated as the first product; The product of the deviation value of the vehicle deceleration and the average deceleration proportionality coefficient is calculated as the second product; The difference between the master cylinder pressure correction value under insufficient braking condition and the first product is used as the first value; The sum of the product of the first value and the second value is calculated as the third updated value.

13. The master cylinder pressure processing method according to claim 11, characterized by, The calculation of the fourth update value based on the master cylinder correction pressure, the pump operation correction pressure, the master cylinder pressure correction value under over-braking conditions, and the master cylinder pressure correction value under under-braking conditions includes: The maximum value between the master cylinder pressure correction value under over-braking conditions and the pump action correction pressure is selected as the second value; The minimum value among the master cylinder pressure correction values ​​under zero and under-braking conditions is selected as the third value; The sum of the master cylinder correction pressure, the second value, and the third value is calculated as the fourth update value.

14. The master cylinder pressure processing method according to claim 11, characterized by, The step of updating the master cylinder correction pressure to obtain the updated master cylinder correction pressure includes: The maximum value between zero and the master cylinder correction pressure is selected as the fourth value; The sum of the fourth value and the master cylinder correction pressure is calculated as the updated master cylinder correction pressure.

15. Master cylinder pressure processing device, characterized in that include: The state machine control module is used to acquire the pressure change rate inside the anti-lock braking system of the vehicle when the vehicle is in the first braking state, and control the vehicle to enter the correction state from the first braking state according to the pressure change rate inside the anti-lock braking system; wherein, the first braking state is used to characterize the state of the vehicle when the anti-lock braking system is activated and the electronic brake-force distribution system is deactivated, and the pressure change rate is used to characterize the amount of pressure change inside the anti-lock braking system per unit time. The pressure estimation module is used to acquire the vehicle's wheel information, under-braking information, over-braking information and characteristic information as the vehicle's overall information when the vehicle is in the correction state, and to obtain the estimated pressure of the vehicle's master cylinder based on the overall vehicle information. The detection module is used to detect the master cylinder pressure of the vehicle at the current moment according to the failure condition; and when the master cylinder pressure is detected to meet the failure condition, to replace the master cylinder pressure with the estimated master cylinder pressure and output it; wherein the failure condition includes either the master cylinder pressure being invalid or the master cylinder pressure exceeding a preset numerical range when the master cylinder pressure is valid.

16. A redundant brake system characterized by, The pressure of the master cylinder is processed by the master cylinder pressure processing method as described in any one of claims 1-14.

17. A vehicle characterized by comprising: Includes the master cylinder pressure handling device as described in claim 15 and / or a redundant braking system as described in claim 16.

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