Commercial vehicle pressure control system and control method

Abstract

The invention relates to the technical field of commercial vehicle brake control systems, in particular to a commercial vehicle pressure control system and method. The control method comprises the steps that after a system is powered on, a control unit conducts self-inspection, and pre-calibrated system parameters are loaded from a nonvolatile memory; collecting system parameters and preprocessing the system parameters; acquiring a target instruction in real time and judging a pressure state in combination with system parameters; constructing a duty ratio analysis model based on the pressure state, the target instruction and the system parameters to determine a target duty ratio; and determining the opening time of the electromagnetic valve according to the target duty ratio and formulating a driving strategy. According to the method, a complete and closed-loop technical scheme from signal preprocessing, intelligent state judgment, accurate duty ratio calculation to final segmented intelligent driving is constructed, so that accurate control over the pressure system of the commercial vehicle is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of commercial vehicle brake control system, and particularly relates to a commercial vehicle pressure control system and a control method. BACKGROUND

[0002] Commercial vehicles, as the core carriers of modern logistics and transportation, the performance of their brake systems is directly related to road traffic safety, transportation efficiency and operating costs. With the rapid development of electronic information technology, traditional pure mechanical or pneumatic brake systems are gradually being replaced by more intelligent and more accurate electronically controlled pneumatic brake systems. Such systems receive driver instructions and vehicle state information through electronic controllers, and accurately modulate brake pressure, which is the basis for realizing vehicle active safety and advanced driving assistance functions. Therefore, developing high-performance and high-reliability electronically controlled pressure control systems and advanced control methods has become a focus and breakthrough direction in the field of commercial vehicle technology, and has important significance for promoting the progress and upgrading of commercial vehicle technology.

[0003] The existing commercial vehicle pressure control system mostly uses traditional PID control or simple on-off control strategy, and has the following defects: first, the system response has a lag, making it difficult to achieve rapid and accurate following of pressure under dynamic brake conditions; second, the control accuracy is limited, which can easily cause pressure overshoot or steady-state error, affecting brake smoothness and safety; third, a single frequency driving mode is used for the solenoid valve, especially during long-time braking, continuous power supply to the coil causes serious heating, which not only has high energy consumption, but also accelerates the aging of the solenoid valve, shortens its service life, and has reliability risks; fourth, the system architecture has high coupling degree and lacks modular design, resulting in poor scalability and difficulty in adapting to upgrades. SUMMARY

[0004] The present application aims to provide a commercial vehicle pressure control system and control method to solve at least one of the problems in the prior art.

[0005] The present application provides the following solutions:

[0006] The present application provides a commercial vehicle pressure control method, comprising:

[0007] After the system is powered on, the control unit performs self-checking and loads pre-calibrated system parameters from the non-volatile memory;

[0008] Collecting system parameters and pre-processing them;

[0009] Real-time acquisition of target instructions and combination with system parameters to determine pressure state;

[0010] Based on the pressure state, target instructions and system parameters, a duty cycle analysis model is constructed to determine the target duty cycle;

[0011] The opening time of the electromagnetic valve is determined according to the target duty ratio, and a driving strategy is formulated.

[0012] Further, the pressure state determination method comprises:

[0013] A signal pressure difference value is determined according to the filtered pressure value and the target brake pressure value;

[0014] When the brake state flag is a brake demand, the pressure state is determined according to the signal pressure difference value, the filtered pressure value and the target brake pressure value;

[0015] When the brake state flag is a non-brake demand, the pressure state is determined according to the brake state flag.

[0016] Further, the absolute difference between the filtered pressure value and the target brake pressure value is taken as the signal pressure difference value;

[0017] When the brake state flag is a brake demand, when the signal pressure difference value is less than or equal to a pressure control dead zone threshold, the pressure state is determined to be a pressure maintaining state; when the signal pressure difference value is greater than the pressure control dead zone threshold, if the target brake pressure value is greater than the filtered pressure value, the pressure state is determined to be an intake pressure increasing state, and if the target brake pressure value is less than the filtered pressure value, the pressure state is determined to be an exhaust pressure decreasing state;

[0018] When the brake state flag is a brake demand, the output of the pressure preparation valve state is a non-working state;

[0019] When the brake state flag is a non-brake demand, if the brake state flag of the last analysis cycle is a brake demand, the current analysis cycle is determined to be a brake release initial stage, the pressure state is determined to be an exhaust pressure decreasing state, and the output of the pressure preparation valve state is a working state; if the brake state flag of the last analysis cycle is a non-brake demand, the current analysis cycle is determined to be a non-control state, the pressure state is determined to be a pressure maintaining state, and the output of the pressure preparation valve state is a non-working state.

[0020] Further, the construction method of the duty ratio analysis model comprises:

[0021] A real-time pressure difference is determined according to the filtered pressure value and the target brake pressure value;

[0022] An analysis direction of the target duty ratio is determined according to the pressure state;

[0023] The target duty ratio is analyzed based on the real-time pressure difference and system parameters.

[0024] Further, the difference between the target brake pressure value and the filtered pressure value is taken as the real-time pressure difference.

[0025] Further, the analysis direction of the target duty cycle is determined according to the pressure state, when the pressure state is the intake pressure-increasing state, the analysis direction of the target duty cycle is set to calculate the target duty cycle of the intake electromagnetic valve, and the duty cycle of the exhaust electromagnetic valve is set to 0, when the pressure state is the exhaust pressure-decreasing state, the analysis direction of the target duty cycle is set to calculate the target duty cycle of the exhaust electromagnetic valve, and the duty cycle of the intake electromagnetic valve is set to 0, when the pressure state is the pressure-maintaining state, the duty cycles of the intake electromagnetic valve and the exhaust electromagnetic valve are both set to 0.

[0026] Further, the target duty cycle is analyzed based on the real-time pressure difference and the system parameters, and the expression of the target duty cycle is TV(k) = TV(k-1) + Kp x [e(k) - e(k-1)] + Ki x e(k) + Kd x [e(k) - 2 x e(k-1) + e(k-2)], wherein TV(k) represents the target duty cycle in the current analysis period, e(k) represents the real-time pressure difference in the current analysis period, Kp represents a proportional coefficient, Ki represents an integral coefficient, and Kd represents a differential coefficient.

[0027] Further, the target duty cycle in the analysis direction of the current target duty cycle is taken as the target duty cycle required for analyzing the electromagnetic valve opening time, and when the pressure state is the pressure-maintaining state, the target duty cycles are both set to 0.

[0028] The electromagnetic valve opening time is analyzed according to the target duty cycle, and the ratio of the target duty cycle to (the basic driving frequency x 100) is taken as the electromagnetic valve opening time.

[0029] Further, the driving strategy is formulated according to the electromagnetic valve opening time and the time threshold parameter, when the electromagnetic valve opening time is less than or equal to the time threshold parameter, the driving strategy is set to generate a PWM signal with the same frequency as the basic driving frequency and the same duty cycle as the target duty cycle, to directly drive the corresponding electromagnetic valve to complete the action, when the electromagnetic valve opening time is greater than the time threshold parameter, the driving strategy is set to, in the time interval of 0 to the time threshold parameter, drive with the basic driving frequency and the duty cycle being the target duty cycle, and in the time interval of the time threshold parameter to the electromagnetic valve opening time, immediately switch the driving frequency to the high-frequency driving frequency and adjust the duty cycle to be the same as the duty cycle parameter.

[0030] On the other hand, the application also provides a commercial vehicle pressure control system, comprising:

[0031] a brake system central controller, which is the highest decision unit, is used for receiving and outputting system parameters and target instructions;

[0032] a state judgment module, which is used for judging the pressure state based on the target instructions and the system parameters;

[0033] A pressure control module is configured to calculate a target duty cycle based on a pressure state, a target instruction and system parameters;

[0034] A valve body driving control module is configured to control a driving frequency of the electromagnetic valve according to the target duty cycle;

[0035] A filtering module is configured to perform software filtering on the system parameters to eliminate noise;

[0036] A bottom layer is a basic software configured to convert an application layer control instruction into a hardware recognizable signal and process a sensor signal;

[0037] A hardware layer includes a sensor signal acquisition filtering circuit and a valve body driving circuit configured to perform signal filtering and PWM signal output;

[0038] A bridge control module is configured to perform pressure control operations.

[0039] Through the above scheme, the following beneficial technical effects are obtained:

[0040] By constructing a complete and closed-loop technical scheme from signal preprocessing, intelligent state judgment, accurate duty cycle calculation to final segmented intelligent driving, multiple pain points in the prior art are comprehensively solved. The overall scheme realizes the collaborative optimization of brake pressure control precision, system response speed and actuator energy efficiency life. The modular design not only improves the maintainability of the system and the adaptability to different vehicle platforms, but also significantly reduces the thermal load of the electromagnetic valve and the system energy consumption under the premise of ensuring brake safety and efficiency through algorithm innovation, thereby prolonging the service life of the key components, reducing the whole life cycle maintenance cost of the vehicle, and having high technical value and economic value. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0042] Figure 1 The flowchart of the commercial vehicle pressure control method of the present embodiment.

[0043] Figure 2 The flowchart of the pressure state judgment method of the present embodiment.

[0044] Figure 3 The flowchart of the construction method of the duty cycle analysis model of the present embodiment.

[0045] Figure 4A structure schematic diagram of a commercial vehicle pressure control system of the embodiment. DETAILED DESCRIPTION

[0046] The commercial vehicle pressure control system and control method disclosed by the present application will be further described in detail below in combination with the accompanying drawings and specific embodiments. It should be noted that the technical features described in the following embodiments or the combination of technical features should not be considered in isolation, and they can be combined with each other to achieve better technical effects. In the drawings of the following embodiments, the same reference numerals appearing in each drawing represent the same features or components and can be applied to different embodiments. Therefore, once a feature is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0047] It should be noted that the structures, proportions, sizes, etc. shown in the drawings attached to the present specification are only used to cooperate with the content disclosed in the specification, so that those skilled in the art can understand and read, and are not used to limit the conditions that the invention can be implemented. Any modification of structure, change of proportion relationship or adjustment of size, which does not affect the effect that the invention can produce and the purpose that the invention can achieve, should fall within the scope of the technical content disclosed by the invention. The scope of the preferred embodiments of the present application includes additional implementations, in which the functions can be performed in a substantially simultaneous manner or in reverse order according to the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0048] Techniques, methods, and equipment known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the authorized specification under appropriate circumstances. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, not as a limitation. Therefore, other examples of exemplary embodiments can have different values.

[0049] In the description of the embodiments of the present application, " / " means or, and "and / or" is used to describe the association relationship of the associated objects, which means that there can be three relationships, such as "A and / or B" means that A and B exist alone, B exists alone, and A and B exist simultaneously. In the description of the embodiments of the present application, "multiple" means two or more embodiments.

[0050] Please refer to Figure 1 The commercial vehicle pressure control method of the embodiment shown, comprising:

[0051] Step S1, after the system is powered on, the control unit performs self-checking and loads the pre-calibrated system parameters from the non-volatile memory, including: drive frequency parameters, time threshold parameters, duty cycle parameters, filtering parameters and pressure control parameters, the drive frequency parameters include the basic drive frequency and the high-frequency drive frequency, the time threshold parameter is the electromagnetic valve opening time threshold, in the embodiment, the time threshold parameter is set to 10ms, which is calibrated based on the electromagnetic characteristics, thermal load capacity and response speed of the electromagnetic valve, the duty cycle parameter is the maintenance duty cycle under high-frequency drive, the filtering parameter is the filtering coefficient of software low-pass filtering, which belongs to (0, 1), and the pressure control parameter includes the pressure control dead zone threshold, the proportional coefficient, the integral coefficient and the differential coefficient of the PID control algorithm.

[0052] Specifically, in step S1 of the embodiment, the self-checking after the system is powered on and the pre-loading of the parameters lay a solid foundation for the stable operation of the entire control system. Its beneficial effects are that it ensures that the system is in the optimal and calibrated working state from the beginning of the start, and avoids control oscillation or failure caused by uncertain or incorrect parameters. By loading the key parameters from the non-volatile memory, the control system can be quickly ready without complex online identification process, significantly improving the startup reliability and consistency of the system. At the same time, this parameterized design provides great convenience for adapting to different vehicle models or brake system configurations, only the stored parameters need to be updated, enhancing the universality and portability of the system.

[0053] Please continue to refer to Figure 1 As shown, the commercial vehicle pressure control method further comprises:

[0054] Step S2, collecting and preprocessing system parameters, the system parameters are collected and processed by the filter module of the hardware layer and the application layer.

[0055] Specifically, in step S2 of the embodiment, the sensor signal collection and filtering circuit in the hardware circuit receives the original voltage signal from the pressure sensor in the bridge control module and performs hardware filtering to preliminarily suppress high-frequency noise. The bottom layer converts the voltage signal filtered by hardware into digital quantity recognizable by the application layer, and the filter module of the application layer performs secondary software filtering on the converted real-time pressure signal.

[0056] Specifically, in step S2 of the embodiment, a first-order lag filter algorithm is used to perform secondary software filtering on the converted real-time pressure signal, and the filtering formula is: Pr(k)=α×Ps(k)+(1-α)×Pr(k-1), where Pr(k) represents the filtered pressure value in the current analysis period, Ps(k) represents the original pressure value collected by the sensor in the current analysis period, and a represents the filtering coefficient.

[0057] Specifically, in the step S2 described in the embodiment, the original signal is preprocessed through the hardware and software double filtering mechanism, which brings significant beneficial effects. It can effectively filter out high-frequency noise and random interference introduced by the sensor itself, line transmission and electromagnetic environment, greatly improving the purity and reliability of the real-time pressure signal. This process ensures that the subsequent state judgment and pressure control decision is made based on high-quality and high-stability input signals, avoiding misjudgment and control inaccuracy caused by signal distortion from the source. In addition, the first-order lag filter algorithm has small calculation amount and low controller resource occupation, which meets the stringent real-time requirements of the system while ensuring the filtering effect, and enhances the robustness of the system under complex working conditions.

[0058] Please continue to refer to Figure 1 The commercial vehicle pressure control method further includes:

[0059] Step S3, real-time acquisition of target instructions and combination of system parameters to judge the pressure state, the target instruction is the target brake pressure value and the brake state flag from the brake system central controller, and the brake state flag includes no brake demand and brake demand.

[0060] Please refer to Figure 2 The pressure state judgment method includes:

[0061] Step S31, determining the signal pressure difference value according to the filtered pressure value and the target brake pressure value.

[0062] Specifically, in the step S31 described in the embodiment, the absolute difference value between the filtered pressure value and the target brake pressure value is taken as the signal pressure difference value.

[0063] Please continue to refer to Figure 2 The pressure state judgment method further includes:

[0064] Step S32, when the brake state flag is brake demand, judging the pressure state according to the signal pressure difference value, the filtered pressure value and the target brake pressure value.

[0065] Specifically, in the step S32 described in the embodiment, when the brake state flag is brake demand, when the signal pressure difference value is less than or equal to the pressure control dead zone threshold, it is determined that the pressure state is the pressure maintaining state; when the signal pressure difference value is greater than the pressure control dead zone threshold, if the target brake pressure value is greater than the filtered pressure value, it is determined that the pressure state is the intake pressure boosting state, and if the target brake pressure value is less than the filtered pressure value, it is determined that the pressure state is the exhaust pressure reducing state.

[0066] Specifically, in step S32, when the braking state flag is a braking demand, the output pressure valve state is a non-working state.

[0067] Specifically, in step S32, when the braking state flag is a braking demand, the output pressure valve state is a working state.

[0068] Please continue to refer to Figure 2 As shown, the pressure state judgment method further comprises:

[0069] In step S33, when the braking state flag is a non-braking demand, the pressure state is determined according to the braking state flag.

[0070] Specifically, in step S32, when the braking state flag is a non-braking demand, if the braking state flag of the previous analysis period is a braking demand, it is determined that the current analysis period is a braking release initial stage, the pressure state is determined to be an exhaust pressure reduction state, and the output pressure valve state is a working state. If the braking state flag of the previous analysis period is a non-braking demand, it is determined that the current analysis period is a non-control state, the pressure state is determined to be a pressure maintaining state, and the output pressure valve state is a non-working state.

[0071] Specifically, in step S32, when the braking state flag first changes from a braking demand to a non-braking demand, the pressure state of the subsequent continuous multiple analysis periods needs to be determined as an exhaust pressure reduction state to realize the delayed closing of the pressure valve. The expected value of the delayed closing duration is the duration for the exhaust electromagnetic valve pressure to decrease from the maximum value to 0. In the analysis, the user can set the value, for example, by collecting the duration for the exhaust electromagnetic valve pressure to decrease from the maximum value to 0 after each braking demand as sample data, and taking the mean value of the sample data as the delayed closing duration to realize the calibration of the delayed closing time.

[0072] Specifically, in step S3, through the comprehensive logical judgment of multiple conditions and multiple states, the accurate analysis of the vehicle braking intention and the current system pressure is realized. The beneficial effects are that the key states such as supercharging, pressure maintaining, pressure reduction, and braking release can be clearly and accurately distinguished, which provides accurate decision basis for the subsequent accurate pressure control. In particular, the special processing of the jump of the braking state flag from "yes" to "no" ensures the complete and smooth release of the brake pressure through the delayed exhaust, avoids the phenomenon of residual pressure leading to drag or incomplete braking, and improves the safety and comfort of braking. This intelligent state machine design enables the system to flexibly cope with various complex driving conditions.

[0073] Please continue to refer toFigure 1 As shown in the figure, the commercial vehicle pressure control method further comprises:

[0074] Step S4, constructing a duty cycle analysis model based on the pressure state, the target instruction and the system parameters to determine the target duty cycle.

[0075] Please refer to Figure 3 As shown in the figure, it is a construction method of the duty cycle analysis model, comprising:

[0076] Step S41, determining a real-time pressure difference according to the filtered pressure value and the target brake pressure value.

[0077] Specifically, in step S41, the difference between the target brake pressure value and the filtered pressure value is taken as the real-time pressure difference.

[0078] Please continue to refer to Figure 3 As shown in the figure, the construction method of the duty cycle analysis model further comprises:

[0079] Step S42, determining the analysis direction of the target duty cycle according to the pressure state.

[0080] Specifically, in step S42, the analysis direction of the target duty cycle is determined according to the pressure state. When the pressure state is the intake pressure boost state, the analysis direction of the target duty cycle is set to calculate the target duty cycle of the intake electromagnetic valve, and the duty cycle of the exhaust electromagnetic valve is set to 0. When the pressure state is the exhaust pressure reduction state, the analysis direction of the target duty cycle is set to calculate the target duty cycle of the exhaust electromagnetic valve, and the duty cycle of the intake electromagnetic valve is set to 0. When the pressure state is the pressure maintaining state, the duty cycles of the intake electromagnetic valve and the exhaust electromagnetic valve are both set to 0.

[0081] Please continue to refer to Figure 3 As shown in the figure, the construction method of the duty cycle analysis model further comprises:

[0082] Step S43, analyzing the target duty cycle based on the real-time pressure difference and the system parameters.

[0083] Specifically, in step S43, the target duty cycle is analyzed based on the real-time pressure difference and the system parameters. The expression of the target duty cycle is: TV(k)=TV(k-1)+Kp×[e(k)-e(k-1)]+Ki×e(k)+Kd×[e(k)-2×e(k-1)+e(k-2)], where TV(k) represents the target duty cycle of the current analysis period, e(k) represents the real-time pressure difference of the current analysis period, Kp represents the proportional coefficient, Ki represents the integral coefficient, and Kd represents the differential coefficient.

[0084] It can be understood that the analysis method of the target duty cycle in the embodiment is not specifically limited, and the target duty cycle can also be analyzed by using a MAP chart query method. The signal pressure difference and the real-time pressure difference are input, the two-dimensional MAP chart pre-calibrated through a bench test is queried, and the target duty cycle is directly output. The method is fast in response and is suitable for steady-state and transient-state working conditions.

[0085] Specifically, in step S4 of the embodiment, the accurate mapping from the pressure deviation to the actuator control quantity is realized by constructing the duty cycle analysis model. The core beneficial effect is to realize high-precision and high-dynamic response control of the brake pressure. Whether the MAP chart query method is used for fast response or the incremental PID algorithm is used to eliminate the static error, the required electromagnetic valve driving duty cycle can be quickly and accurately calculated according to the real-time pressure difference. This dynamic adjustment mechanism enables the system to quickly respond to large pressure demand changes and finely tune when approaching the target pressure, thereby effectively reducing the overshoot and oscillation of the pressure, ensuring the smoothness and stability of the braking process, and significantly improving the braking efficiency.

[0086] Please continue to refer to Figure 1 As shown in the figure, the commercial vehicle pressure control method further comprises:

[0087] Step S5, determining the electromagnetic valve opening time according to the target duty cycle and formulating a driving strategy.

[0088] Specifically, in step S5 of the embodiment, the target duty cycle in the analysis direction of the current target duty cycle is taken as the target duty cycle required for analyzing the electromagnetic valve opening time. If the pressure state is a pressure maintaining state, the target duty cycle is also set to 0.

[0089] Specifically, in step S5 of the embodiment, the electromagnetic valve opening time is analyzed according to the target duty cycle, and the ratio of the target duty cycle to (the basic driving frequency x 100) is taken as the electromagnetic valve opening time. The unit of the electromagnetic valve opening time is converted to milliseconds.

[0090] Specifically, in step S5 of the embodiment, the driving strategy is formulated according to the electromagnetic valve opening time and the time threshold parameter. When the electromagnetic valve opening time is less than or equal to the time threshold parameter, the driving strategy is set as: generating a PWM signal with the same frequency as the basic driving frequency and the same duty cycle as the target duty cycle to directly drive the corresponding electromagnetic valve to complete the action; when the electromagnetic valve opening time is greater than the time threshold parameter, the driving strategy is set as: within the time interval of 0 to the time threshold parameter, the basic driving frequency and the duty cycle of the target duty cycle are used for driving; within the time interval of the time threshold parameter to the electromagnetic valve opening time, the driving frequency is immediately switched to the high-frequency driving frequency, and the duty cycle is adjusted to the same as the duty cycle parameter.

[0091] Specifically, in step S5, the energy consumption and thermal management of the solenoid valve are fundamentally optimized by intelligently switching between the conventional driving strategy and the segmented driving strategy according to the required opening time of the solenoid valve. When a long opening time is required, the segmented strategy of "first strong and then maintain" is adopted, which greatly reduces the average current of the coil in the maintenance phase while ensuring the reliable opening of the valve core and the control of the flow. This design directly brings two great advantages: first, it significantly reduces the continuous heat generation of the solenoid valve, effectively avoiding performance degradation or permanent damage due to overheating; second, the overall energy consumption of the system is reduced, which helps to improve the energy efficiency of the vehicle and prolong the service life of related components.

[0092] Referring to Figure 4 The commercial vehicle pressure control system of the present embodiment includes:

[0093] The brake system central controller is the highest decision unit, which is used to receive and output system parameters and target instructions;

[0094] The state judgment module is used to judge the pressure state based on the target instructions and system parameters;

[0095] The pressure control module is used to calculate the target duty cycle based on the pressure state, target instructions and system parameters;

[0096] The valve body driving control module is used to control the driving frequency of the solenoid valve according to the target duty cycle;

[0097] The filter module is used to perform software filtering on the system parameters to eliminate noise;

[0098] The bottom layer is the basic software, which is used to convert the control instructions of the application layer into hardware recognizable signals and process sensor signals;

[0099] The hardware layer includes sensor signal acquisition and filtering circuit and valve body driving circuit, which is used for signal filtering and PWM signal output;

[0100] The bridge control module is used to perform pressure control operations.

[0101] In the above description, the disclosure of the application is not intended to be limited to the aspects described. Rather, the components can be selectively combined in any number of ways, as operative and optional, within the scope of the intended target protection of the disclosure. In addition, terms like "include," "comprise," and "have" should be construed as inclusive or open-ended, rather than exclusive or closed, unless specifically defined as such. All technical, scientific, or other terms have the meaning as understood by those skilled in the art, unless specifically defined to the contrary. Common terms found in dictionaries are not to be interpreted too ideally or too unrealistically in the context of the relevant technical documents, unless specifically defined as such by the disclosure. Any changes, modifications, made by those of ordinary skill in the art based on the above disclosure are within the scope of protection of the claims.

Claims

1. A pressure control method for commercial vehicles, characterized in that, The commercial vehicle pressure control method includes: After the system is powered on, the control unit performs a self-test and loads pre-calibrated system parameters from non-volatile memory; Collect system parameters and preprocess them; Real-time acquisition of target commands and determination of pressure status based on system parameters; A duty cycle analysis model is constructed based on pressure status, target commands, and system parameters to determine the target duty cycle. The opening time of the solenoid valve is determined based on the target duty cycle, and a driving strategy is formulated.

2. The commercial vehicle pressure control method according to claim 1, characterized in that, Methods for determining pressure status include: The signal pressure difference is determined based on the filtered pressure value and the target braking pressure value. When the braking status indicator indicates that braking is required, the pressure status is determined based on the signal pressure difference, the filtered pressure value, and the target braking pressure value. When the braking status indicator indicates no braking demand, the pressure status is determined based on the braking status indicator.

3. The commercial vehicle pressure control method according to claim 2, characterized in that, The absolute difference between the filtered pressure value and the target braking pressure value is taken as the signal pressure difference. When the braking status indicator indicates that braking is required, if the signal pressure difference is less than or equal to the pressure control dead zone threshold, the pressure status is determined to be a pressure holding state; if the signal pressure difference is greater than the pressure control dead zone threshold, if the target braking pressure value is greater than the filtered pressure value, the pressure status is determined to be an intake boosting state; if the target braking pressure value is less than the filtered pressure value, the pressure status is determined to be an exhaust depressurization state. When the braking status indicator indicates that braking is required, the output backup pressure valve is in a non-operating state. When the braking status indicator is "no braking demand", if the braking status indicator of the previous analysis cycle is "braking demand", then the current analysis cycle is determined to be the initial stage of brake release, the pressure status is determined to be the exhaust pressure reduction state, and the output backup pressure valve status is the working state. If the braking status indicator of the previous analysis cycle is "no braking demand", then the current analysis cycle is determined to be the "no control" state, the pressure status is determined to be the "pressure holding" state, and the output backup pressure valve status is the "non-working" state.

4. The commercial vehicle pressure control method according to claim 1, characterized in that, Methods for constructing duty cycle analysis models include: The real-time pressure difference is determined based on the filtered pressure value and the target braking pressure value. The analytical direction for determining the target duty cycle is based on the pressure status; The target duty cycle is analyzed based on real-time pressure difference and system parameters.

5. The commercial vehicle pressure control method according to claim 4, characterized in that, The difference between the target braking pressure value and the filtered pressure value is used as the real-time pressure difference.

6. The commercial vehicle pressure control method according to claim 5, characterized in that, The analysis direction for determining the target duty cycle is based on the pressure state. When the pressure state is in the intake boosting state, the analysis direction for the target duty cycle is set to calculate the target duty cycle of the intake solenoid valve, and the duty cycle of the exhaust solenoid valve is set to 0. When the pressure state is in the exhaust depressurization state, the analysis direction for the target duty cycle is set to calculate the target duty cycle of the exhaust solenoid valve, and the duty cycle of the intake solenoid valve is set to 0. When the pressure state is in the pressure holding state, the duty cycles of both the intake solenoid valve and the exhaust solenoid valve are set to 0.

7. The commercial vehicle pressure control method according to claim 6, characterized in that, The target duty cycle is analyzed based on the real-time pressure difference and system parameters. The expression for the target duty cycle is: TV(k)=TV(k-1)+Kp×[e(k)-e(k-1)]+Ki×e(k)+Kd×[e(k)-2×e(k-1)+e(k-2)], where TV(k) represents the target duty cycle of the current analysis period, e(k) represents the real-time pressure difference of the current analysis period, Kp represents the proportional coefficient, Ki represents the integral coefficient, and Kd represents the differential coefficient.

8. The commercial vehicle pressure control method according to claim 1, characterized in that, The target duty cycle of the current target duty cycle is used as the target duty cycle required to analyze the opening time of the solenoid valve. If the pressure state is the pressure holding state, the target duty cycle is set to 0. The solenoid valve opening time is analyzed based on the target duty cycle, and the ratio of the target duty cycle to (basic drive frequency × 100) is taken as the solenoid valve opening time.

9. The commercial vehicle pressure control method according to claim 8, characterized in that, A driving strategy is formulated based on the solenoid valve opening time and time threshold parameter. When the solenoid valve opening time is less than or equal to the time threshold parameter, the driving strategy is set as follows: generate a PWM signal with the same frequency as the basic driving frequency and the same duty cycle as the target duty cycle, and directly drive the corresponding solenoid valve to complete the action. When the solenoid valve opening time is greater than the time threshold parameter, the driving strategy is set as follows: within the time interval from 0 to the time threshold parameter, drive with the basic driving frequency and duty cycle as the target duty cycle. Within the time interval from the time threshold parameter to the solenoid valve opening time, immediately switch the driving frequency to a high-frequency driving frequency and adjust the duty cycle to be the same as the duty cycle parameter.

10. A commercial vehicle pressure control system, applied to the commercial vehicle pressure control method as described in any one of claims 1-9, characterized in that, include: The central controller of the braking system is the highest decision-making unit, used to receive and output system parameters and target commands; The status determination module is used to determine the pressure status based on the target command and system parameters; The pressure control module is used to calculate the target duty cycle based on pressure status, target commands, and system parameters; The valve body drive control module is used to control the solenoid valve drive frequency according to the target duty cycle; The filtering module is used to perform software filtering on system parameters to eliminate noise; The bottom layer, which is the basic software, is used to convert application layer control commands into hardware-recognizable signals and process sensor signals; The hardware layer includes sensor signal acquisition and filtering circuits and valve body drive circuits, used for signal filtering and PWM signal output; The bridge control module is used to perform pressure control operations.

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