Pressure control method and system for automobile brake-by-wire system

Abstract

The invention relates to a pressure control method and system for an automobile brake-by-wire system and relates to the technical field of brake-by-wire systems, and the method comprises the steps that temperature data, humidity data and pollution degree data of hydraulic oil are collected in real time and recorded as hydraulic oil characteristic data; pressure sensors are arranged at an outlet of a hydraulic source and first to fourth brake wheel cylinders to obtain real-time pressure data in the braking process; the control assembly receives actual opening data collected by the pedal travel sensor and determines target hydraulic pressure; inputting the temperature data, the humidity data and the pollution degree data which are acquired in real time into a pre-constructed relation model; comparing the collected real-time pressure data with the target hydraulic pressure to obtain an actual pressure difference value; a pressure compensation command is generated in the control component based on the pressure deviation and the actual pressure difference.

Description

Technical Field

[0001] The present application relates to the technical field of brake-by-wire systems, and in particular to a pressure control method and system for a brake-by-wire system of an automobile. Background Art

[0002] The automobile braking system is the direct device for realizing automobile braking control and plays a vital role in automobile stability and safety.

[0003] Patent publication number CN114750733A discloses a wire control brake system and control method for an automobile, wherein the system includes: a brake assembly, the brake assembly includes a hydraulic source with a motor, a fluid storage tank and correspondingly arranged first to fourth brake wheel cylinders; a brake pedal; a pedal travel sensor for collecting the actual opening of the brake pedal; at least one pressure sensor for collecting the actual braking pressure of at least one of the first to fourth brake wheel cylinders; a control assembly for identifying the driver's current braking intention from the actual opening, determining the target hydraulic pressure based on the current braking intention, and controlling the brake assembly to perform the corresponding braking action according to the target hydraulic pressure, and driving the pressure regulating valve to correct the braking action based on the actual braking pressure.

[0004] Hydraulic oil is the key medium for transmitting pressure in the braking system. Changes in its temperature, humidity and contamination level will significantly affect the pressure transmission effect. However, this point is not taken into consideration in the technical solution of the above-mentioned patent. How to solve this problem is a technical challenge that technical personnel in this field need to overcome. Summary of the invention

[0005] In order to at least partially solve the above technical problems, the present application provides a pressure control method and system for an automobile wire control brake system.

[0006] In a first aspect, the present application provides a pressure control method for an automobile brake-by-wire system that adopts the following technical solution.

[0007] A pressure control method for a vehicle brake-by-wire system, comprising: Collect temperature data, humidity data and contamination degree data of hydraulic oil in real time and record them as hydraulic oil characteristic data; Pressure sensors are arranged at the hydraulic source outlet and the first to fourth brake wheel cylinders to obtain real-time pressure data during braking; The control component receives actual opening data collected by the pedal travel sensor and determines a target hydraulic pressure; Input the real-time collected temperature data, humidity data, and pollution degree data into a pre-built relationship model; the relationship model predicts the pressure deviation caused by the change of hydraulic oil characteristics based on the input hydraulic oil characteristic data; Compare the collected real-time pressure data with the target hydraulic pressure to obtain the actual pressure difference; Based on the pressure deviation and the actual pressure difference, a pressure compensation instruction is generated in the control component to adjust the target hydraulic pressure to obtain a corrected target hydraulic pressure; When the control component issues an action command to control the brake component, the pressure value in the action command is compensated and corrected based on the corrected target hydraulic pressure; the brake component acts according to the corrected action command to make the actual output pressure closer to the initially determined target hydraulic pressure.

[0008] By adopting the above technical solution, the command pressure value is compensated and corrected based on the corrected target hydraulic pressure, so that the actual pressure output by the brake component is closer to the initially determined target hydraulic pressure; the stability and reliability of the braking system are improved, the brake pressure deviation caused by changes in hydraulic oil characteristics and other factors is reduced, and the braking performance and driving safety of the entire vehicle are improved.

[0009] Optionally, when the control component receives the actual opening data collected by the pedal travel sensor, it also determines the target hydraulic pressure in combination with the real-time driving speed, acceleration, and slope information of the vehicle, specifically including: The control component obtains in real time the actual opening value of the brake pedal collected by the pedal travel sensor, the real-time driving speed collected by the vehicle speed sensor, the real-time acceleration collected by the acceleration sensor, and the slope of the road where the vehicle is located measured by the slope sensor; Determine the domains for the actual brake pedal opening value, real-time driving speed, real-time acceleration and slope respectively, and divide the fuzzy subsets on each domain; According to the preset membership function, the membership of the actual brake pedal opening value, the real-time driving speed, the real-time acceleration and the slope to the respective fuzzy subsets is calculated respectively; Reasoning is performed based on the membership of the input variables and the fuzzy rule base, and the premise membership of each rule is obtained by taking the minimum operation, and the fuzzy subset of the output variable target hydraulic pressure and its membership are determined; Based on the reasoning results of all rules, the fuzzy set of target hydraulic pressure is obtained; The fuzzy set of target hydraulic pressures is converted into a target hydraulic pressure value.

[0010] Optionally, based on the pressure deviation and the actual pressure difference, a pressure compensation instruction is generated in the control component, including: The total error is obtained by combining the pressure deviation caused by the change in hydraulic oil characteristics and the actual pressure difference obtained by comparing the collected real-time pressure data with the target hydraulic pressure; Calculating the proportional term, the integral term and the differential term; adding the proportional term, the integral term and the differential term to obtain a first control output of the PID controller, wherein the first control output is the initial value of the pressure compensation instruction; The control component determines the current braking condition according to the real-time driving status of the vehicle and the working condition of the braking system; Under emergency braking conditions, increase the proportional coefficient, reduce the integral coefficient and increase the differential coefficient to speed up the system response, avoid overshoot caused by integral saturation and suppress system oscillation; Under slow braking conditions, reduce the proportional coefficient and increase the integral coefficient to avoid excessive braking and eliminate steady-state errors; According to the judged braking conditions and the corresponding parameter adjustment strategy, the values ​​of the proportional coefficient, the integral coefficient and the differential coefficient are updated in real time; The proportional term, the integral term and the differential term are recalculated using the adjusted PID parameters, and a second control output is obtained, which is the final pressure compensation instruction.

[0011] Optionally, the method further includes: Set the maximum adjustment range; The corrected target hydraulic pressure is compared with the maximum adjustment range: if the corrected target hydraulic pressure exceeds the maximum adjustment range, the control component triggers the alarm system to warn the driver through sound, light or instrument panel prompt.

[0012] Optionally, the method further includes: The control component records the vehicle's usage time and mileage in real time; During each braking process, the actual brake pedal opening value, real-time driving speed, real-time acceleration, slope, and the corresponding target hydraulic pressure value and actual brake output pressure value are recorded; Setting a usage time threshold and a mileage threshold; when the usage time of the vehicle exceeds the time threshold or the mileage exceeds the mileage threshold, the adjustment mechanism of the fuzzy rule base is triggered; When the adjustment condition is triggered, the braking effect indicators of several recorded braking processes are statistically analyzed to calculate the average braking distance and average braking deceleration; The average braking effect index is compared with the preset ideal braking effect index; if the average braking distance is greater than the ideal braking distance, it is considered that the braking effect is poor and the fuzzy rule base needs to be adjusted; According to the specific working conditions where the braking effect is not good, determine the working condition range where the fuzzy rules need to be corrected; For fuzzy rules within the determined working condition range, the fuzzy subset of the target hydraulic pressure in the rule conclusion is adjusted according to the direction and size of the deviation between the braking effect and the ideal effect.

[0013] Optionally, real-time data collection of hydraulic oil temperature, humidity and contamination data is available, including: Use temperature sensors to collect the temperature of the hydraulic oil in real time; Use capacitive humidity sensor to obtain the humidity data of hydraulic oil; An optical particle counter is used to detect the contamination degree of hydraulic oil.

[0014] Optionally, the pre-built relationship model is a prediction model based on a neural network, and the relationship model uses the temperature, humidity and contamination degree of the hydraulic oil as an input layer and the pressure deviation as an output layer.

[0015] Optionally, the method for constructing the relationship model includes: Constructing a generator network; the generator network is used to predict future pressure deviations based on historical hydraulic oil characteristic data; the generator network includes a feature extraction convolution layer, an upsampling layer, a residual block and a jump connection module; the feature extraction convolution layer is used to extract key features from historical hydraulic oil characteristic data to help the network understand the potential patterns and laws in the data; the upsampling layer is used to increase the time step so that the pressure deviation at a future time point can be predicted; the residual block is used to alleviate the gradient vanishing problem; the jump connection module is used to maintain the information transmission of low-level features during the upsampling process; Constructing a discriminator network; the discriminator network is mainly used to evaluate whether the pressure deviation prediction value of the generator network is consistent with the actual pressure deviation condition; the discriminator network comprises: a feature extraction convolution layer and a fully connected layer; the feature extraction convolution layer is used to extract features from the prediction results of the generator to analyze the feature patterns of the prediction results; the fully connected layer is used to evaluate whether the pressure deviation prediction is consistent with the actual pressure deviation and give a discriminant result; Construct a loss function module; the loss function module is used to quantify the difference between the generated pressure deviation prediction and the actual pressure deviation status; the loss function module includes: a content loss module and an adversarial loss module; the content loss module is used to measure the difference between the generated pressure deviation prediction and the actual pressure deviation status, so as to encourage the generator to generate a prediction closer to the actual value; the adversarial loss module is used to encourage the generator to generate a prediction closer to the actual pressure deviation status, and improve the performance of the generator through adversarial training with the discriminator.

[0016] In a second aspect, the present application provides a pressure control system for an automobile brake-by-wire system that adopts the following technical solution.

[0017] A pressure control system for an automobile brake-by-wire system, characterized by comprising: The first processing module is used to collect temperature data, humidity data and pollution degree data of the hydraulic oil in real time and record them as hydraulic oil characteristic data; The second processing module is used to: set pressure sensors at the hydraulic source outlet and the first to fourth brake wheel cylinders to obtain real-time pressure data during braking; The third processing module is used to: the control component receives the actual opening data collected by the pedal travel sensor and determines the target hydraulic pressure; The fourth processing module is used to: input the real-time collected temperature data, humidity data, and pollution degree data into a pre-built relationship model; the relationship model predicts the pressure deviation caused by the change of hydraulic oil characteristics according to the input hydraulic oil characteristic data; A fifth processing module is used to compare the collected real-time pressure data with the target hydraulic pressure to obtain an actual pressure difference; a sixth processing module, configured to: generate a pressure compensation instruction in the control component based on the pressure deviation and the actual pressure difference, and adjust the target hydraulic pressure to obtain a corrected target hydraulic pressure; The seventh processing module is used to: when the control component issues an action instruction to control the brake component, use the corrected target hydraulic pressure as a reference to compensate and correct the pressure value in the action instruction; the brake component acts according to the corrected action instruction to make the actual output pressure closer to the initially determined target hydraulic pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a flow chart of a pressure control method for a vehicle brake-by-wire system according to an embodiment of the present application; Figure 2 This is a system block diagram of a pressure control method for an automobile brake-by-wire system according to an embodiment of the present application; In the figure, 201 is a first processing module; 202 is a second processing module; 203 is a third processing module; 204 is a fourth processing module; 205 is a fifth processing module; 206 is a sixth processing module; and 207 is a seventh processing module. DETAILED DESCRIPTION

[0019] The following is combined with Figure 1-2 The present application is further described with specific embodiments: The present application embodiment discloses a pressure control method for a vehicle brake-by-wire system, comprising the following steps: Step 101: collect temperature data, humidity data and pollution degree data of hydraulic oil in real time, and record them as hydraulic oil characteristic data.

[0020] Step 102: Pressure sensors are provided at the hydraulic source outlet and the first to fourth brake wheel cylinders to obtain real-time pressure data during the braking process.

[0021] Step 103: The control component receives actual opening data collected by the pedal travel sensor and determines a target hydraulic pressure.

[0022] Step 104: input the real-time collected temperature data, humidity data, and pollution degree data into a pre-built relationship model; the relationship model predicts the pressure deviation caused by the change of hydraulic oil characteristics based on the input hydraulic oil characteristic data.

[0023] Step 105: Compare the collected real-time pressure data with the target hydraulic pressure to obtain an actual pressure difference.

[0024] Step 106: Based on the pressure deviation and the actual pressure difference, a pressure compensation instruction is generated in the control component, and the target hydraulic pressure is adjusted to obtain a corrected target hydraulic pressure.

[0025] Step 107, when the control component issues an action command to control the brake component, the corrected target hydraulic pressure is used as a reference to compensate and correct the pressure value in the action command; the brake component acts according to the corrected action command to make the actual output pressure closer to the initially determined target hydraulic pressure.

[0026] Specifically, by collecting the temperature, humidity and contamination degree data of the hydraulic oil in real time as the hydraulic oil characteristic data, and obtaining the real-time pressure data at the hydraulic source outlet and each brake wheel cylinder, the control component determines the target hydraulic pressure according to the actual opening data collected by the pedal stroke sensor; the hydraulic oil characteristic data is input into a pre-constructed relationship model, and the relationship model predicts the pressure deviation caused by the change of the hydraulic oil characteristics based on the relationship between the hydraulic oil characteristics and the pressure deviation; the actual pressure difference is obtained by comparing the real-time pressure data with the target hydraulic pressure; based on these two key data, the control component generates a pressure compensation instruction, adjusts the target hydraulic pressure, and obtains the corrected target hydraulic pressure; when issuing a control brake component action instruction, the command pressure value is compensated and corrected based on the corrected target hydraulic pressure, so that the actual pressure output by the brake component is closer to the initially determined target hydraulic pressure; the stability and reliability of the braking system are improved, the brake pressure deviation caused by the change of hydraulic oil characteristics and other factors is reduced, and the braking performance and driving safety of the whole vehicle are improved.

[0027] As a specific implementation method for a pressure control method of a vehicle brake-by-wire system, when a control component receives actual opening data collected by a pedal travel sensor and also determines a target hydraulic pressure in combination with the vehicle's real-time driving speed, acceleration, and slope information, specifically including: The control component obtains in real time the actual opening value of the brake pedal collected by the pedal travel sensor, the real-time driving speed collected by the vehicle speed sensor, the real-time acceleration collected by the acceleration sensor, and the slope of the road where the vehicle is located measured by the slope sensor; Determine the domains for the actual brake pedal opening value, real-time driving speed, real-time acceleration and slope respectively, and divide the fuzzy subsets on each domain; According to the preset membership function, the membership of the actual brake pedal opening value, the real-time driving speed, the real-time acceleration and the slope to the respective fuzzy subsets is calculated respectively; Reasoning is performed based on the membership of the input variables and the fuzzy rule base, and the premise membership of each rule is obtained by taking the minimum operation, and the fuzzy subset of the output variable target hydraulic pressure and its membership are determined; Based on the reasoning results of all rules, the fuzzy set of target hydraulic pressure is obtained; The fuzzy set of target hydraulic pressures is converted into a target hydraulic pressure value.

[0028] Specifically, in the automobile wire control brake system, when determining the target hydraulic pressure, the control component not only relies on the actual opening data collected by the pedal travel sensor, but also comprehensively considers the vehicle's real-time driving speed, acceleration, road slope and other information; determines the domain for each data and divides the fuzzy subset; then calculates the membership of each data to the corresponding fuzzy subset based on the preset membership function, quantifies the degree of belonging of each data in different categories; reasoning is performed on the membership of the input variable combined with the fuzzy rule base, and the fuzzy subset and its membership of the target hydraulic pressure are determined by taking the minimum operation; based on the reasoning results of all rules, the fuzzy set of the target hydraulic pressure is obtained, and various possible situations are comprehensively considered to form a target hydraulic pressure set covering multiple possibilities. The fuzzy set is converted into a target hydraulic pressure value, and the fuzzy result is converted into an accurate value that can be actually applied to the control of the braking system. The automobile wire control brake system can determine the target hydraulic pressure more accurately and intelligently according to the actual driving conditions of the vehicle and the driver's intention.

[0029] As a specific implementation of a pressure control method for a brake-by-wire system of an automobile, a pressure compensation instruction is generated in a control component based on a pressure deviation and an actual pressure difference, including: The total error is obtained by combining the pressure deviation caused by the change in hydraulic oil characteristics and the actual pressure difference obtained by comparing the collected real-time pressure data with the target hydraulic pressure; Calculating the proportional term, the integral term and the differential term; adding the proportional term, the integral term and the differential term to obtain a first control output of the PID controller, wherein the first control output is the initial value of the pressure compensation instruction; The control component determines the current braking condition according to the real-time driving status of the vehicle and the working condition of the braking system; Under emergency braking conditions, increase the proportional coefficient, reduce the integral coefficient and increase the differential coefficient to speed up the system response, avoid overshoot caused by integral saturation and suppress system oscillation; Under slow braking conditions, reduce the proportional coefficient and increase the integral coefficient to avoid excessive braking and eliminate steady-state errors; According to the judged braking conditions and the corresponding parameter adjustment strategy, the values ​​of the proportional coefficient, the integral coefficient and the differential coefficient are updated in real time; The proportional term, the integral term and the differential term are recalculated using the adjusted PID parameters, and a second control output is obtained, which is the final pressure compensation instruction.

[0030] Specifically, the total error is obtained by combining the pressure deviation caused by the change in hydraulic oil characteristics with the actual pressure difference obtained by comparing the real-time pressure and the target hydraulic pressure; based on this total error, the PID control algorithm is used to calculate and add the proportional term, integral term and differential term to obtain the initial value of the pressure compensation command. The PID algorithm can adjust the control output in a proportional, integral and differential manner according to the error situation, and preliminarily provide a compensation command that adapts to the pressure deviation. The control component determines the current braking condition based on the real-time driving state of the vehicle and the working condition of the braking system; under emergency braking conditions, increasing the proportional coefficient allows the system to respond quickly to the pressure deviation and speed up the response speed, reducing the integral coefficient to avoid the overshoot problem caused by integral saturation, and increasing the differential coefficient to suppress system oscillation, ensuring that the braking pressure can quickly and stably reach the expected level in an emergency, ensuring the braking effect and driving safety; and under slow braking conditions, reducing the proportional coefficient prevents excessive braking, and increasing the integral coefficient effectively eliminates steady-state errors, making the braking process smoother and more comfortable. According to different braking conditions, the PID parameters are updated in real time, so that the PID control algorithm can closely fit the actual braking needs of the vehicle and realize dynamic optimization of parameters. Finally, the final pressure compensation command is recalculated using the adjusted PID parameters to improve the adaptability of the braking system.

[0031] As a specific implementation of a pressure control method for a vehicle brake-by-wire system, the method further includes: Set the maximum adjustment range; The corrected target hydraulic pressure is compared with the maximum adjustment range: if the corrected target hydraulic pressure exceeds the maximum adjustment range, the control component triggers the alarm system to warn the driver through sound, light or instrument panel prompt.

[0032] As one implementation of a pressure control method for a brake-by-wire system of an automobile, the method further includes: The control component records the vehicle's usage time and mileage in real time; During each braking process, the actual brake pedal opening value, real-time driving speed, real-time acceleration, slope, and the corresponding target hydraulic pressure value and actual brake output pressure value are recorded; Setting a usage time threshold and a mileage threshold; when the usage time of the vehicle exceeds the time threshold or the mileage exceeds the mileage threshold, the adjustment mechanism of the fuzzy rule base is triggered; When the adjustment condition is triggered, the braking effect indicators of several recorded braking processes are statistically analyzed to calculate the average braking distance and average braking deceleration; The average braking effect index is compared with the preset ideal braking effect index; if the average braking distance is greater than the ideal braking distance, it is considered that the braking effect is poor and the fuzzy rule base needs to be adjusted; According to the specific working conditions where the braking effect is not good, determine the working condition range where the fuzzy rules need to be corrected; For fuzzy rules within the determined working condition range, the fuzzy subset of the target hydraulic pressure in the rule conclusion is adjusted according to the direction and size of the deviation between the braking effect and the ideal effect.

[0033] Specifically, during the operation of the automobile's wire control brake system, the control component records in real time the vehicle's usage time and mileage, as well as key data during each braking process, such as the actual brake pedal opening value, real-time driving speed, real-time acceleration, slope, target hydraulic pressure value and actual brake output pressure value; sets a usage time threshold and a mileage threshold. When the vehicle's usage time exceeds the time threshold or the mileage exceeds the mileage threshold, the adjustment mechanism of the fuzzy rule base is triggered. Based on the fact that after a vehicle has been used for a long time, its brake system components may experience wear and performance changes, etc., the system can adapt to changes in vehicle performance by triggering adjustments in a timely manner. After the adjustment conditions are triggered, the braking effect indicators of several recorded braking processes, such as the average braking distance and the average braking deceleration, are statistically analyzed; the average braking effect indicator is compared with the preset ideal braking effect indicator. If the average braking distance is greater than the ideal braking distance, the braking effect is judged to be poor, and the adjustment of the fuzzy rule base is initiated; according to the specific working conditions where the braking effect is poor, the working condition range of the fuzzy rules to be corrected is determined to ensure the pertinence of the adjustment and avoid blindly modifying the rules; the fuzzy rules within the working condition range are determined, and the fuzzy subset of the target hydraulic pressure in the rule conclusion is adjusted according to the direction and size of the deviation between the braking effect and the ideal effect. In this way, the system can dynamically optimize the fuzzy rule base according to the changes in the actual braking performance of the vehicle, so that the braking system can always maintain a relatively ideal braking effect during the long-term use of the vehicle.

[0034] As one implementation of a pressure control method for a vehicle brake-by-wire system, real-time acquisition of temperature data, humidity data, and contamination degree data of hydraulic oil includes: Use temperature sensors to collect the temperature of the hydraulic oil in real time; Use capacitive humidity sensor to obtain the humidity data of hydraulic oil; An optical particle counter is used to detect the contamination degree of hydraulic oil.

[0035] As one implementation of a pressure control method for a brake-by-wire system of an automobile, the method for constructing the relationship model includes: Constructing a generator network; the generator network is used to predict future pressure deviations based on historical hydraulic oil characteristic data; the generator network includes a feature extraction convolution layer, an upsampling layer, a residual block and a jump connection module; the feature extraction convolution layer is used to extract key features from historical hydraulic oil characteristic data to help the network understand the potential patterns and laws in the data; the upsampling layer is used to increase the time step so that the pressure deviation at a future time point can be predicted; the residual block is used to alleviate the gradient vanishing problem; the jump connection module is used to maintain the information transmission of low-level features during the upsampling process; Construct a discriminator network; the discriminator network is mainly used to evaluate whether the pressure deviation prediction value of the generator network is consistent with the actual pressure deviation condition; the discriminator network includes: a feature extraction convolution layer and a fully connected layer; the feature extraction convolution layer is used to extract features from the prediction results of the generator to analyze the feature patterns of the prediction results; the fully connected layer is used to evaluate whether the pressure deviation prediction is consistent with the actual pressure deviation and give a discriminant result; Construct a loss function module; the loss function module is used to quantify the difference between the generated pressure deviation prediction and the actual pressure deviation status; the loss function module includes: a content loss module and an adversarial loss module; the content loss module is used to measure the difference between the generated pressure deviation prediction and the actual pressure deviation status, so as to encourage the generator to generate a prediction closer to the actual value; the adversarial loss module is used to encourage the generator to generate a prediction closer to the actual pressure deviation status, and improve the performance of the generator through adversarial training with the discriminator.

[0036] The present application also provides a pressure control system for an automobile wire control brake system, comprising: The first processing module 201 is used to collect temperature data, humidity data and pollution degree data of hydraulic oil in real time, and record them as hydraulic oil characteristic data; The second processing module 202 is used to: set pressure sensors at the hydraulic source outlet and the first to fourth brake wheel cylinders to obtain real-time pressure data during braking; The third processing module 203 is used to: the control component receives the actual opening data collected by the pedal travel sensor and determines the target hydraulic pressure; The fourth processing module 204 is used to: input the real-time collected temperature data, humidity data, and pollution degree data into a pre-built relationship model; the relationship model predicts the pressure deviation caused by the change of hydraulic oil characteristics according to the input hydraulic oil characteristic data; The fifth processing module 205 is used to compare the collected real-time pressure data with the target hydraulic pressure to obtain an actual pressure difference; The sixth processing module 206 is used to: generate a pressure compensation instruction in the control component based on the pressure deviation and the actual pressure difference, and adjust the target hydraulic pressure to obtain a corrected target hydraulic pressure; The seventh processing module 207 is used to: when the control component issues an action instruction to control the brake component, use the corrected target hydraulic pressure as a reference to compensate and correct the pressure value in the action instruction; the brake component acts according to the corrected action instruction to make the actual output pressure closer to the initially determined target hydraulic pressure.

[0037] It should be noted that the above embodiments are only used to illustrate the present application and are not intended to limit the technical solutions described in the present application. Although the present application has been described in detail in this specification with reference to the above embodiments, a person of ordinary skill in the art should understand that a person of ordinary skill in the art can still modify or make equivalent substitutions to the present application, and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present application should be included in the scope of the claims of the present application.

Claims

1. A pressure control method for a vehicle brake-by-wire system, characterized in that: include: Collect temperature data, humidity data and contamination degree data of hydraulic oil in real time and record them as hydraulic oil characteristic data; Pressure sensors are arranged at the hydraulic source outlet and the first to fourth brake wheel cylinders to obtain real-time pressure data during braking; The control component receives actual opening data collected by the pedal travel sensor and determines a target hydraulic pressure; Input the real-time collected temperature data, humidity data, and pollution degree data into the pre-built relational model; The relationship model predicts the pressure deviation caused by the change of hydraulic oil characteristics according to the input hydraulic oil characteristic data; Compare the collected real-time pressure data with the target hydraulic pressure to obtain the actual pressure difference; Based on the pressure deviation and the actual pressure difference, a pressure compensation instruction is generated in the control component to adjust the target hydraulic pressure to obtain a corrected target hydraulic pressure; When the control component issues an action command to control the brake component, the pressure value in the action command is compensated and corrected based on the corrected target hydraulic pressure; the brake component acts according to the corrected action command to make the actual output pressure closer to the initially determined target hydraulic pressure.

2. A pressure control method for a vehicle brake-by-wire system according to claim 1, characterized in that: When the control component receives the actual opening data collected by the pedal travel sensor, it also determines the target hydraulic pressure in combination with the vehicle's real-time driving speed, acceleration, and slope information, including: The control component obtains in real time the actual opening value of the brake pedal collected by the pedal travel sensor, the real-time driving speed collected by the vehicle speed sensor, the real-time acceleration collected by the acceleration sensor, and the slope of the road where the vehicle is located measured by the slope sensor; Determine the domains for the actual brake pedal opening value, real-time driving speed, real-time acceleration and slope respectively, and divide the fuzzy subsets on each domain; According to the preset membership function, the membership of the actual brake pedal opening value, the real-time driving speed, the real-time acceleration and the slope to the respective fuzzy subsets is calculated respectively; Reasoning is performed based on the membership of the input variables and the fuzzy rule base, and the premise membership of each rule is obtained by taking the minimum operation, and the fuzzy subset of the output variable target hydraulic pressure and its membership are determined; Based on the reasoning results of all rules, the fuzzy set of target hydraulic pressure is obtained; The fuzzy set of target hydraulic pressures is converted into a target hydraulic pressure value.

3. A pressure control method for a vehicle brake-by-wire system according to claim 2, characterized in that: Based on the pressure deviation and the actual pressure difference, a pressure compensation command is generated in the control component, including: The total error is obtained by combining the pressure deviation caused by the change in hydraulic oil characteristics and the actual pressure difference obtained by comparing the collected real-time pressure data with the target hydraulic pressure; Calculating the proportional term, the integral term and the differential term; adding the proportional term, the integral term and the differential term to obtain a first control output of the PID controller, wherein the first control output is the initial value of the pressure compensation instruction; The control component determines the current braking condition according to the real-time driving status of the vehicle and the working condition of the braking system; Under emergency braking conditions, increase the proportional coefficient, reduce the integral coefficient and increase the differential coefficient to speed up the system response, avoid overshoot caused by integral saturation and suppress system oscillation; Under slow braking conditions, reduce the proportional coefficient and increase the integral coefficient to avoid excessive braking and eliminate steady-state errors; According to the judged braking conditions and the corresponding parameter adjustment strategy, the values ​​of the proportional coefficient, the integral coefficient and the differential coefficient are updated in real time; The proportional term, the integral term and the differential term are recalculated using the adjusted PID parameters, and a second control output is obtained, which is the final pressure compensation instruction.

4. The pressure control method for a vehicle brake-by-wire system according to claim 3, characterized in that: The method further comprises: Set the maximum adjustment range; The corrected target hydraulic pressure is compared with the maximum adjustment range: if the corrected target hydraulic pressure exceeds the maximum adjustment range, the control component triggers the alarm system to warn the driver through sound, light or instrument panel prompt.

5. The pressure control method for a vehicle brake-by-wire system according to claim 4, characterized in that: The method further comprises: The control component records the vehicle's usage time and mileage in real time; During each braking process, the actual brake pedal opening value, real-time driving speed, real-time acceleration, slope, and the corresponding target hydraulic pressure value and actual brake output pressure value are recorded; Setting a usage time threshold and a mileage threshold; when the usage time of the vehicle exceeds the time threshold or the mileage exceeds the mileage threshold, the adjustment mechanism of the fuzzy rule base is triggered; When the adjustment condition is triggered, the braking effect indicators of several recorded braking processes are statistically analyzed to calculate the average braking distance and average braking deceleration; The average braking effect index is compared with the preset ideal braking effect index; if the average braking distance is greater than the ideal braking distance, it is considered that the braking effect is poor and the fuzzy rule base needs to be adjusted; According to the specific working conditions where the braking effect is not good, determine the working condition range where the fuzzy rules need to be corrected; For fuzzy rules within the determined working condition range, the fuzzy subset of the target hydraulic pressure in the rule conclusion is adjusted according to the direction and size of the deviation between the braking effect and the ideal effect.

6. The pressure control method for a vehicle brake-by-wire system according to claim 5, characterized in that: Real-time collection of hydraulic oil temperature data, humidity data and contamination data, including: Use temperature sensors to collect the temperature of hydraulic oil in real time; Use capacitive humidity sensor to obtain the humidity data of hydraulic oil; An optical particle counter is used to detect the contamination degree of hydraulic oil.

7. The pressure control method for a vehicle brake-by-wire system according to claim 6, characterized in that: The pre-built relationship model is a prediction model based on a neural network, and the relationship model uses the temperature, humidity and contamination degree of the hydraulic oil as an input layer and the pressure deviation as an output layer.

8. The pressure control method for a vehicle brake-by-wire system according to claim 7, characterized in that: The method for constructing the relationship model includes: Constructing a generator network; the generator network is used to predict future pressure deviations based on historical hydraulic oil characteristic data; the generator network includes a feature extraction convolution layer, an upsampling layer, a residual block and a jump connection module; the feature extraction convolution layer is used to extract key features from historical hydraulic oil characteristic data to help the network understand the potential patterns and laws in the data; the upsampling layer is used to increase the time step so that the pressure deviation at a future time point can be predicted; the residual block is used to alleviate the gradient vanishing problem; the jump connection module is used to maintain the information transmission of low-level features during the upsampling process; Constructing a discriminator network; the discriminator network is mainly used to evaluate whether the pressure deviation prediction value of the generator network is consistent with the actual pressure deviation condition; the discriminator network comprises: a feature extraction convolution layer and a fully connected layer; the feature extraction convolution layer is used to extract features from the prediction results of the generator to analyze the feature patterns of the prediction results; the fully connected layer is used to evaluate whether the pressure deviation prediction is consistent with the actual pressure deviation and give a discriminant result; Construct a loss function module; the loss function module is used to quantify the difference between the generated pressure deviation prediction and the actual pressure deviation status; the loss function module includes: a content loss module and an adversarial loss module; the content loss module is used to measure the difference between the generated pressure deviation prediction and the actual pressure deviation status, so as to encourage the generator to generate a prediction closer to the actual value; the adversarial loss module is used to encourage the generator to generate a prediction closer to the actual pressure deviation status, and improve the performance of the generator through adversarial training with the discriminator.

9. A pressure control system for an automobile brake-by-wire system, characterized in that: include: The first processing module is used to collect temperature data, humidity data and pollution degree data of the hydraulic oil in real time and record them as hydraulic oil characteristic data; The second processing module is used to: set pressure sensors at the hydraulic source outlet and the first to fourth brake wheel cylinders to obtain real-time pressure data during braking; The third processing module is used to: the control component receives the actual opening data collected by the pedal travel sensor and determines the target hydraulic pressure; The fourth processing module is used to: input the real-time collected temperature data, humidity data, and pollution degree data into a pre-built relationship model; The relationship model predicts the pressure deviation caused by the change of hydraulic oil characteristics according to the input hydraulic oil characteristic data; A fifth processing module is used to compare the collected real-time pressure data with the target hydraulic pressure to obtain an actual pressure difference; a sixth processing module, configured to: generate a pressure compensation instruction in the control component based on the pressure deviation and the actual pressure difference, and adjust the target hydraulic pressure to obtain a corrected target hydraulic pressure; The seventh processing module is used to: when the control component issues an action instruction to control the brake component, use the corrected target hydraulic pressure as a reference to compensate and correct the pressure value in the action instruction; the brake component acts according to the corrected action instruction to make the actual output pressure closer to the initially determined target hydraulic pressure.

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