An EHB low-speed operating brake pressure smooth control method and system

Abstract

The application relates to an EHB low-speed working condition brake pressure smooth control method and system, and belongs to the brake pressure smooth control technical field.The method comprises the following steps: collecting vehicle speed, target brake pressure and piston movement speed in real time; presetting a speed threshold value, a brake pressure threshold value and a movement speed threshold value of a low-speed micro-brake working condition; judging the sizes of the vehicle speed and the speed threshold value, the target brake pressure and the brake pressure threshold value and the piston movement speed and the movement speed threshold value respectively; when the judgment result is that the vehicle speed is smaller than the speed threshold value, the target brake pressure is smaller than the brake pressure threshold value and the piston movement speed is smaller than the movement speed threshold value, it is determined that the vehicle is in the low-speed micro-brake working condition, and segmented gain PID control is triggered; wherein the segmented gain PID control is divided into three segments. Through the segmented gain control, the pressure can be controlled more finely, so that the pressure fluctuation, pressure overshoot and the like are reduced, and the driving comfort is improved.

Description

Technical Field

[0001] This invention belongs to the field of brake pressure stabilization control technology, and particularly relates to a method and system for stabilizing brake pressure under EHB low-speed conditions. Background Technology

[0002] The EHB (Electronic Brake-by-Wire) system uses a motor and lead screw mechanism to drive a piston to achieve active pressure build-up. However, in everyday driving conditions such as low-speed micro-braking and creeping (e.g., following other vehicles in congested city traffic or braking while maneuvering at low speeds), the existing technology has the following significant drawbacks: 1. During low-speed micro-braking, the friction between the piston and the seal ring, as well as the mechanical clearance of the lead screw assembly, can cause the braking pressure to oscillate and vibrate. When this vibration is transmitted to the brake pedal, it produces a noticeable tremor, affecting driving comfort. 2. Traditional PID control uses a fixed gain, which makes it difficult to balance the smoothness and response speed of low-speed micro-braking. Too high a gain can easily lead to pressure jitter, while too low a gain can easily lead to slow pressure response. 3. The existing control scheme does not introduce a targeted self-learning compensation mechanism, which cannot adapt to the frictional changes caused by the wear of components over long-term use. The vibration problem will gradually worsen with the duration of use, and calibration is difficult. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the purpose of the invention is to provide a method and system for smooth control of braking pressure in EHB low-speed conditions. By adopting segmented gain control, the pressure can be controlled more precisely, thereby reducing pressure fluctuations and pressure overshoot, improving driving comfort. By adding a self-learning correction function, the actual pressure during daily operation is collected, and the calculated pressure obtained by the calibration formula is combined to calculate the steady-state deviation. After classification, it is used for correction and compensation after component wear, improving pressure accuracy, enhancing safety and driving experience.

[0004] In a first aspect, the present invention provides a method for smooth control of braking pressure under EHB low-speed conditions, comprising three steps S1 to S3: S1: Real-time acquisition of vehicle speed, target braking pressure, and piston movement speed; preset speed threshold, braking pressure threshold, and movement speed threshold for low-speed micro-braking conditions. S2: Determine the magnitudes of vehicle speed and speed threshold, target braking pressure and braking pressure threshold, and piston movement speed and movement speed threshold, respectively; S3: When the judgment result is that the vehicle speed is less than the speed threshold, the target braking pressure is less than the braking pressure threshold, and the piston movement speed is less than the movement speed threshold, the vehicle is determined to be in a low-speed micro-braking condition, and the piecewise gain PID control is triggered. The piecewise gain PID control is divided into three segments.

[0005] Furthermore, the aforementioned method for smooth control of braking pressure under low-speed EHB conditions also includes: If the judgment results are not met (vehicle speed is less than the speed threshold, target braking pressure is less than the braking pressure threshold, and piston movement speed is less than the movement speed threshold), the vehicle is determined to be in a non-low-speed micro-braking condition, and compensation is performed using calibrated and matched fixed gain parameters.

[0006] Furthermore, in the aforementioned method for smooth braking pressure control under EHB low-speed conditions, the first segment of the piecewise gain PID control includes: When the actual pressure is less than a first preset percentage of the target pressure, conventional PID gain is used.

[0007] Furthermore, in the aforementioned method for smooth braking pressure control under EHB low-speed conditions, the second stage of the piecewise gain PID control includes: When the actual pressure is greater than or equal to the target pressure by a first preset percentage but less than the target pressure by a second preset percentage, switch to low gain.

[0008] Furthermore, in the aforementioned method for smooth braking pressure control under EHB low-speed conditions, the third segment of the piecewise gain PID control includes: When the actual pressure is greater than or equal to the second preset percentage of the target pressure, a small-amplitude PID control dead zone is introduced, while limiting the maximum speed of the motor.

[0009] Furthermore, the aforementioned method for smooth control of braking pressure under EHB low-speed operating conditions also includes four steps, S21 to S24: S21: Under low-speed micro-braking conditions, when the actual pressure reaches the target pressure value, collect the real steady-state pressure and the synchronous piston displacement. S22: Based on the mapping relationship between piston displacement and braking pressure calibrated on the test bench, the estimated displacement pressure at the same time is calculated. S23: Calculate the steady-state deviation between the actual steady-state pressure and the displacement-estimated pressure; S24: Store steady-state deviations according to piston displacement ranges. When entering low-speed micro-braking conditions, automatically call the steady-state deviation of the corresponding piston displacement range to compensate for the target pressure.

[0010] Furthermore, in the aforementioned method for smooth control of braking pressure under EHB low-speed conditions, the steady-state deviation between the actual steady-state pressure and the displacement-estimated pressure is calculated, including: The steady-state deviation is obtained by subtracting the actual steady-state pressure from the displacement-estimated pressure.

[0011] A second aspect of the present invention also proposes an EHB low-speed braking pressure stabilization control system, comprising: The data acquisition module and the preset module are used to acquire vehicle speed, target braking pressure, and piston movement speed in real time, and to preset speed thresholds, braking pressure thresholds, and movement speed thresholds for low-speed micro-braking conditions. Judgment module: used to determine the magnitude of vehicle speed and speed threshold, target braking pressure and braking pressure threshold, and piston movement speed and movement speed threshold respectively; Trigger module: When the judgment result is that the vehicle speed is less than the speed threshold, the target braking pressure is less than the braking pressure threshold, and the piston movement speed is less than the movement speed threshold, the vehicle is determined to be in a low-speed micro-braking condition, and the segmented gain PID control is triggered. The piecewise gain PID control is divided into three segments.

[0012] A third aspect of the present invention also provides an electronic device comprising: a processor and a memory; The processor executes one of the above-mentioned EHB low-speed braking pressure stabilization control methods by calling programs or instructions stored in memory.

[0013] In a fourth aspect, the present invention also provides a computer-readable storage medium storing a program or instructions that cause a computer to execute any of the above-mentioned EHB low-speed braking pressure stabilization control methods.

[0014] The beneficial effects of this invention are as follows: 1) In existing technologies, friction between the piston and the sealing ring and mechanical clearance of the lead screw assembly during low-speed micro-braking can cause oscillations and vibrations in the braking pressure. These vibrations are transmitted to the brake pedal, resulting in a noticeable tremor and affecting driving comfort. Traditional PID control uses a fixed gain, which makes it difficult to balance the smoothness and response speed of low-speed micro-braking. Excessive gain can easily lead to pressure oscillations, while insufficient gain can easily lead to slow pressure response. This invention uses segmented gain control, which can control the pressure more precisely, thereby reducing pressure fluctuations and pressure overshoot, and improving driving comfort.

[0015] 2) The existing control scheme does not introduce a targeted self-learning compensation mechanism, which cannot adapt to the frictional changes caused by the wear of components over a long period of use. The vibration problem will gradually worsen with the duration of use, and the calibration is difficult. By adding a self-learning correction function, the actual pressure during daily operation is collected and the calculated pressure is obtained by combining the calibration formula. The steady-state deviation is calculated and classified, and then used for correction and compensation after component wear, thereby improving pressure accuracy, safety and driving experience. Attached Figure Description

[0016] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. It is obvious that the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings.

[0017] Figure 1 A schematic diagram of an EHB low-speed braking pressure stabilization control method provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of a method for compensating steady-state deviation under low-speed micro-braking conditions provided by an embodiment of the present invention; Figure 3 A schematic diagram of an EHB low-speed braking pressure stabilization control system provided in an embodiment of the present invention; Figure 4 This is a schematic block diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0019] Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts disclosed in this invention.

[0020] In the description of this invention, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "installed," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of methods and systems consistent with some aspects of the invention as detailed in the appended claims.

[0022] This invention proposes a method, system, electronic device, and storage medium for stable braking pressure control under EHB low-speed conditions. By employing segmented gain control, pressure control can be made more precise, thereby reducing pressure fluctuations and pressure overshoot, and improving driving comfort. By adding a self-learning correction function, the actual pressure during daily operation is collected and combined with the calculated pressure obtained from the calibration formula to calculate the steady-state deviation. After classification, the deviation is used for correction and compensation after component wear, thereby improving pressure accuracy, enhancing safety, and improving the driving experience.

[0023] Method Implementation Examples In a first aspect, the present invention proposes a method for stable control of braking pressure under EHB low-speed operating conditions, combined with Figure 1 It includes three steps: S1 to S3. S1: Real-time acquisition of vehicle speed, target braking pressure, and piston movement speed, with preset speed thresholds, braking pressure thresholds, and movement speed thresholds for low-speed micro-braking conditions.

[0024] Specifically, in this embodiment of the invention, the real-time acquisition of vehicle speed, target braking pressure, and piston movement speed is achieved through a controller. The controller presets speed thresholds, braking pressure thresholds, and movement speed thresholds for low-speed micro-braking conditions. For example, the controller acquires a real-time vehicle speed of 14 km / h, a target braking pressure of 20 bar, and a piston movement speed of 10 m / s. The controller presets speed thresholds of 15 km / h, braking pressure thresholds of 30 bar, and movement speed thresholds of 15 m / s for low-speed micro-braking conditions.

[0025] S2: Determine the magnitudes of vehicle speed and speed threshold, target braking pressure and braking pressure threshold, and piston movement speed and movement speed threshold, respectively.

[0026] Specifically, in this embodiment of the invention, the controller determines the magnitude of vehicle speed and speed threshold, target braking pressure and braking pressure threshold, and piston movement speed and movement speed threshold, respectively. For example, the controller determines the magnitude of vehicle speed 14km / h and speed threshold 15km / h, target braking pressure 20bar and braking pressure threshold 30bar, and piston movement speed 10m / s and movement speed threshold 15m / s, respectively.

[0027] S3: When the judgment result is that the vehicle speed is less than the speed threshold, the target braking pressure is less than the braking pressure threshold, and the piston movement speed is less than the movement speed threshold, it is determined that the vehicle is in a low-speed micro-braking condition, and the segmented gain PID control is triggered.

[0028] Specifically, in this embodiment of the invention, when the controller determines that the vehicle speed is less than the speed threshold, the target braking pressure is less than the braking pressure threshold, and the piston movement speed is less than the movement speed threshold, the vehicle is determined to be in a low-speed micro-braking condition, and segmented gain PID control is triggered. For example, when the controller determines that the vehicle speed is 14 km / h less than the speed threshold of 15 km / h, the target braking pressure is 20 bar less than the braking pressure threshold of 30 bar, and the piston movement speed is 10 m / s less than the movement speed threshold of 15 m / s, the vehicle is determined to be in a low-speed micro-braking condition, and segmented gain PID control is triggered.

[0029] The piecewise gain PID control is divided into three segments.

[0030] Specifically, in this embodiment of the invention, the segmented gain PID control is divided into three stages: the initial stage of pressure build-up, the middle stage of pressure build-up, and the final stage of pressure build-up. These stages will be described in detail below with specific numerical values.

[0031] Furthermore, the aforementioned method for smooth control of braking pressure under low-speed EHB conditions also includes: If the judgment results are not met (vehicle speed is less than the speed threshold, target braking pressure is less than the braking pressure threshold, and piston movement speed is less than the movement speed threshold), the vehicle is determined to be in a non-low-speed micro-braking condition, and compensation is performed using calibrated and matched fixed gain parameters.

[0032] Specifically, in this embodiment of the invention, when the controller's judgment result does not meet the requirements of vehicle speed being less than a speed threshold, target braking pressure being less than a braking pressure threshold, and piston movement speed being a movement speed threshold, the vehicle is determined to be in a non-low-speed micro-braking condition, and compensation is performed using calibrated and matched fixed gain parameters. For example: when the controller's judgment result is that the vehicle speed is 16 km / h, which is greater than the speed threshold of 15 km / h, the target braking pressure is 40 bar, which is greater than the braking pressure threshold of 30 bar, and the piston movement speed is 17 m / s, which is greater than the movement speed threshold of 15 m / s, the vehicle is determined to be in a non-low-speed micro-braking condition, and compensation is performed using calibrated and matched fixed gain parameters.

[0033] Furthermore, in the aforementioned method for smooth braking pressure control under EHB low-speed conditions, the first segment of the piecewise gain PID control includes: When the actual pressure is less than a first preset percentage of the target pressure, conventional PID gain is used.

[0034] Specifically, in this embodiment of the invention, the first stage of the segmented gain PID control is the initial pressure build-up stage. When the actual pressure is less than 70% of the target pressure, conventional PID gain is used to ensure the pressure build-up response speed and avoid braking sluggishness. For example, if the driver needs a braking pressure of 30 bar, then in the first stage from 0 to 20 bar, a calibrated conventional gain mode is used to make the motor thrust greater. This mode has a fast pressure build-up speed and can be simply understood as a high-speed mode.

[0035] Furthermore, in the aforementioned method for smooth braking pressure control under EHB low-speed conditions, the second stage of the piecewise gain PID control includes: When the actual pressure is greater than or equal to the target pressure by a first preset percentage but less than the target pressure by a second preset percentage, switch to low gain.

[0036] Specifically, in this embodiment of the invention, the second stage of the segmented gain PID control is the pressure build-up phase. When the actual pressure is greater than or equal to a first preset percentage of the target pressure (70%) and less than a second preset percentage of the target pressure (90%), it automatically switches to a low proportional gain to reduce the sensitivity of PID adjustment, avoid high-frequency correction due to small pressure deviations, and reduce pressure jitter. For example, at this point, the pressure has reached 20 bar, and the next stage is between 20 bar and 28 bar. If the motor continues to push hard, it is easy to overshoot. Therefore, the motor thrust is reduced here and adjusted to a medium speed mode to avoid overshoot.

[0037] Furthermore, in the aforementioned method for smooth braking pressure control under EHB low-speed conditions, the third segment of the piecewise gain PID control includes: When the actual pressure is greater than or equal to the second preset percentage of the target pressure, a small-amplitude PID control dead zone is introduced, while limiting the maximum speed of the motor.

[0038] Specifically, in this embodiment of the invention, the third stage of the segmented gain PID control is the end of the pressure build-up period. When the actual pressure is greater than or equal to the second preset percentage of the target pressure (90%), a small-amplitude PID adjustment dead zone is introduced, and the maximum speed of the motor is limited, so that the piston slowly approaches the target pressure to avoid pressure overshoot and oscillation. For example, at this time, the pressure has reached 28-30 bar, which is very close to the target pressure. The thrust of the second stage medium speed mode is no longer applicable, so it is necessary to continue to reduce the motor thrust to make the piston move slowly and slowly approach the target pressure. This belongs to the low speed mode.

[0039] Furthermore, in the aforementioned EHB low-speed braking pressure stabilization control method, under low-speed micro-braking conditions, when the pressure reaches the target value and is in a steady state, the controller periodically executes a self-learning process to automatically compensate for inherent system deviations, combined with... Figure 2It also includes four steps, S21 to S24: S21: Under low-speed micro-braking conditions, when the actual pressure reaches the target pressure value, the real steady-state pressure and synchronous piston displacement are collected.

[0040] Specifically, in this embodiment of the invention, under low-speed micro-braking conditions, when the actual pressure reaches the target pressure value, the real steady-state pressure P_real fed back by the current pressure sensor is collected, and the piston displacement x is collected simultaneously.

[0041] S22: Based on the mapping relationship between piston displacement and braking pressure calibrated on the test bench, the estimated displacement pressure at the same time is calculated.

[0042] Specifically, in this embodiment of the invention, the estimated displacement pressure P_calc is calculated based on the piston displacement-braking pressure mapping relationship P_base = f(x) calibrated on the test bench.

[0043] S23: Calculate the steady-state deviation between the actual steady-state pressure and the displacement-estimated pressure.

[0044] Specifically, in this embodiment of the invention, the steady-state deviation offset between the actual steady-state pressure P_real and the estimated displacement pressure P_calc is calculated. This steady-state deviation offset is used to compensate for pressure fluctuations caused by component wear and mechanical clearance.

[0045] S24: Store steady-state deviations according to piston displacement ranges. When entering low-speed micro-braking conditions, automatically call the steady-state deviation of the corresponding piston displacement range to compensate for the target pressure.

[0046] Specifically, in this embodiment of the invention, the steady-state deviation offset is classified according to the piston displacement range, such as into three ranges: 0-70%, 71%-90%, and 91%-100%, and stored in the controller's non-volatile memory. When entering the low-speed micro-braking condition, the offset of the corresponding range is automatically called to compensate for the target pressure and suppress pressure fluctuation. Here, offset can be simply understood as a calibration value, used to compensate for the difference after long-term wear. For example, in the 0-70% displacement range, the self-learning result is 2 bar, and the controller will automatically make up for this 2 bar.

[0047] Furthermore, in the aforementioned method for smooth control of braking pressure under EHB low-speed conditions, the steady-state deviation between the actual steady-state pressure and the displacement-estimated pressure is calculated, including: The steady-state deviation is obtained by subtracting the actual steady-state pressure from the displacement-estimated pressure.

[0048] Specifically, in this embodiment of the invention, the steady-state deviation offset, which is the difference between the actual steady-state pressure P_real and the estimated displacement pressure P_calc during the same period, is expressed by the following formula: offset = P_real - P_calc System Implementation Examples In a second aspect, the present invention also proposes an EHB low-speed braking pressure stabilization control system, combined with Figure 3 ,include: Acquisition module 31 and preset module 32 are used to acquire vehicle speed, target braking pressure, and piston movement speed in real time, and to preset speed threshold, braking pressure threshold, and movement speed threshold for low-speed micro-braking conditions.

[0049] Specifically, in this embodiment of the invention, the real-time acquisition of vehicle speed, target braking pressure, and piston movement speed is achieved through the acquisition module 31 in the controller. The speed threshold, braking pressure threshold, and movement speed threshold for low-speed micro-braking conditions are preset in the preset module 32 of the controller. For example, the real-time vehicle speed acquired by the acquisition module 31 of the controller is 14 km / h, the target braking pressure is 20 bar, and the piston movement speed is 10 m / s. The speed threshold, braking pressure threshold, and movement speed threshold of 15 km / h, 30 bar, and 15 m / s for low-speed micro-braking conditions are preset in the preset module 32 of the controller.

[0050] Judgment module 33: used to determine the magnitude of vehicle speed and speed threshold, target braking pressure and braking pressure threshold, and piston movement speed and movement speed threshold respectively.

[0051] The judgment module 33 in the controller judges the magnitude of vehicle speed and speed threshold, target braking pressure and braking pressure threshold, and piston movement speed and movement speed threshold, respectively. For example, the judgment module 33 of the controller judges the magnitude of vehicle speed 14km / h and speed threshold 15km / h, target braking pressure 20bar and braking pressure threshold 30bar, and piston movement speed 10m / s and movement speed threshold 15m / s, respectively.

[0052] Trigger module 34: When the judgment result is that the vehicle speed is less than the speed threshold, the target braking pressure is less than the braking pressure threshold, and the piston movement speed is less than the movement speed threshold, the vehicle is determined to be in a low-speed micro-braking condition, and the segmented gain PID control is triggered.

[0053] Specifically, in this embodiment of the invention, when the judgment result of the controller's judgment module 33 is that the vehicle speed is less than the speed threshold, the target braking pressure is less than the braking pressure threshold, and the piston movement speed is less than the movement speed threshold, it is determined that the vehicle is in a low-speed micro-braking condition, and the trigger module 34 triggers segmented gain PID control; for example: when the judgment result of the controller's judgment module 33 is that the vehicle speed is 14 km / h less than the speed threshold of 15 km / h, the target braking pressure is 20 bar less than the braking pressure threshold of 30 bar, and the piston movement speed is 10 m / s less than the movement speed threshold of 15 m / s, it is determined that the vehicle is in a low-speed micro-braking condition, and the trigger module 34 triggers segmented gain PID control.

[0054] The piecewise gain PID control is divided into three segments.

[0055] Specifically, in this embodiment of the invention, the segmented gain PID control is divided into three stages: the initial stage of pressure build-up, the middle stage of pressure build-up, and the final stage of pressure build-up.

[0056] A third aspect of the present invention also provides an electronic device comprising: a processor and a memory; The processor executes one of the above-mentioned EHB low-speed braking pressure stabilization control methods by calling programs or instructions stored in memory.

[0057] In a fourth aspect, the present invention also provides a computer-readable storage medium storing a program or instructions that cause a computer to execute any of the above-mentioned EHB low-speed braking pressure stabilization control methods.

[0058] Figure 4 This is a schematic block diagram of an electronic device provided in an embodiment of the present invention.

[0059] like Figure 4 As shown, the electronic device includes at least one processor 401, at least one memory 402, and at least one communication interface 403. The various components of the electronic device are coupled together via a bus system 404. The communication interface 403 is used for information transmission with external devices. It is understood that the bus system 404 is used to implement communication between these components. In addition to a data bus, the bus system 404 also includes a power bus, a control bus, and a status signal bus. However, for clarity, ... Figure 4 The general designated all buses as Bus System 404.

[0060] It is understood that the memory 402 in this embodiment can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory.

[0061] In some implementations, memory 402 stores elements such as executable units or data structures, or subsets thereof, or extended sets thereof: operating systems and applications.

[0062] The operating system includes various system programs, such as the framework layer, core library layer, and driver layer, used to implement various basic business functions and handle hardware-based tasks. The application programs include various applications, such as media players and browsers, used to implement various application functions. The program implementing any method in the EHB low-speed braking pressure stabilization control method provided in this embodiment of the invention can be included in the application programs.

[0063] In this embodiment of the invention, the processor 401 executes the steps of various embodiments of the EHB low-speed braking pressure stabilization control method provided by the present invention by calling the program or instructions stored in the memory 402, specifically, the program or instructions stored in the application program.

[0064] S1: Real-time acquisition of vehicle speed, target braking pressure, and piston movement speed; preset speed threshold, braking pressure threshold, and movement speed threshold for low-speed micro-braking conditions. S2: Determine the magnitudes of vehicle speed and speed threshold, target braking pressure and braking pressure threshold, and piston movement speed and movement speed threshold, respectively; S3: When the judgment result is that the vehicle speed is less than the speed threshold, the target braking pressure is less than the braking pressure threshold, and the piston movement speed is less than the movement speed threshold, the vehicle is determined to be in a low-speed micro-braking condition, and the piecewise gain PID control is triggered. The piecewise gain PID control is divided into three segments.

[0065] Any method in the EHB low-speed braking pressure stabilization control method provided in this embodiment of the invention can be applied to, or implemented by, the processor 401. The processor 401 can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of the processor 401 or by instructions in software form. The processor 401 can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor or any conventional processor.

[0066] The steps of any method in the EHB low-speed braking pressure stabilization control method provided in this embodiment of the invention can be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software units in the decoding processor. The software units can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory 402, and processor 401 reads the information in memory 402 and combines it with hardware to complete the steps of the method.

[0067] Those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention and form different embodiments.

[0068] Those skilled in the art will understand that the descriptions of the various embodiments have different focuses, and for parts not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0069] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

[0070] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for stable control of braking pressure under EHB low-speed operating conditions, characterized in that, It includes three steps: S1 to S3. S1: Real-time acquisition of vehicle speed, target braking pressure, and piston movement speed; preset speed threshold, braking pressure threshold, and movement speed threshold for low-speed micro-braking conditions. S2: Determine the magnitudes of the vehicle speed and the speed threshold, the target braking pressure and the braking pressure threshold, and the piston movement speed and the movement speed threshold, respectively; S3: When the judgment result is that the vehicle speed is less than the speed threshold, the target braking pressure is less than the braking pressure threshold, and the piston movement speed is less than the movement speed threshold, the vehicle is determined to be in a low-speed micro-braking condition, and segmented gain PID control is triggered. The piecewise gain PID control is divided into three segments.

2. The method for stable control of braking pressure under EHB low-speed conditions according to claim 1, characterized in that, The method further includes: If the judgment results are not met (the vehicle speed is less than the speed threshold, the target braking pressure is less than the braking pressure threshold, and the piston movement speed is less than the movement speed threshold), the vehicle is determined to be in a non-low-speed micro-braking condition, and compensation is performed using calibrated and matched fixed gain parameters.

3. The method for stable control of braking pressure under EHB low-speed conditions according to claim 1, characterized in that, The first segment in piecewise gain PID control includes: When the actual pressure is less than a first preset percentage of the target pressure, conventional PID gain is used.

4. The method for stable control of braking pressure under EHB low-speed conditions according to claim 1, characterized in that, The second segment in piecewise gain PID control includes: When the actual pressure is greater than or equal to the target pressure by a first preset percentage but less than the target pressure by a second preset percentage, switch to low gain.

5. The method for stable control of braking pressure under EHB low-speed conditions according to claim 1, characterized in that, The third segment in piecewise gain PID control includes: When the actual pressure is greater than or equal to the second preset percentage of the target pressure, a small-amplitude PID control dead zone is introduced, while limiting the maximum speed of the motor.

6. The method for stable control of braking pressure under EHB low-speed conditions according to claim 1, characterized in that, The method further includes four steps, S21 to S24: S21: Under low-speed micro-braking conditions, when the actual pressure reaches the target pressure value, collect the real steady-state pressure and the synchronous piston displacement. S22: Based on the mapping relationship between piston displacement and braking pressure calibrated on the test bench, the estimated displacement pressure at the same time is calculated. S23: Calculate the steady-state deviation between the actual steady-state pressure and the displacement-estimated pressure; S24: Store steady-state deviations according to piston displacement ranges. When entering low-speed micro-braking conditions, automatically call the steady-state deviation of the corresponding piston displacement range to compensate for the target pressure.

7. The method for stable control of braking pressure under EHB low-speed conditions according to claim 6, characterized in that, Calculate the steady-state deviation between the true steady-state pressure and the displacement-estimated pressure, including: The steady-state deviation is obtained by subtracting the actual steady-state pressure from the estimated displacement pressure.

8. An EHB low-speed braking pressure stabilization control system, characterized in that, include: The data acquisition module and the preset module are used to acquire vehicle speed, target braking pressure, and piston movement speed in real time, and to preset speed thresholds, braking pressure thresholds, and movement speed thresholds for low-speed micro-braking conditions. Judgment module: used to determine the magnitudes of the vehicle speed and the speed threshold, the target braking pressure and the braking pressure threshold, and the piston movement speed and the movement speed threshold, respectively; Trigger module: When the judgment result is that the vehicle speed is less than the speed threshold, the target braking pressure is less than the braking pressure threshold, and the piston movement speed is less than the movement speed threshold, the vehicle is determined to be in a low-speed micro-braking condition, and the segmented gain PID control is triggered. The piecewise gain PID control is divided into three segments.

9. An electronic device, characterized in that, include: Processor and memory; The processor executes the EHB low-speed braking pressure stabilization control method as described in any one of claims 1 to 7 by calling the program or instructions stored in the memory.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a program or instructions that cause a computer to execute an EHB low-speed braking pressure stabilization control method as described in any one of claims 1 to 7.

Images