Electronic parking release control method and system based on CAN bus

Abstract

The invention provides an electronic parking release control method and system based on a CAN bus, and belongs to the technical field of automobile control. The method comprises the steps that vehicle information such as current gearbox gear, speed ratio, gradient, vehicle weight, accelerator opening degree, brake, actual engine torque, accessory torque and electronic parking system state is obtained from a CAN bus in real time and used for judging the current working condition of a vehicle, and the expected engine torque needed for successful starting and no sliding of the vehicle under the current working condition is calculated in real time; and when the engine net torque is larger than or equal to the expected engine torque and under the condition that the redundancy mistake proofing condition is met, the electronic parking system is automatically released, and the vehicle is started. The vehicle brake release time can be automatically adjusted according to the vehicle weight, the gradient and the starting gear, and the starting comfort, acceleration and safety are improved.

Description

Technical Field

[0001] This invention belongs to the field of automotive control technology, and more specifically relates to an electronic parking release control method and system based on CAN bus. Background Technology

[0002] Electronic parking brake (EPB) systems, as an alternative to traditional mechanical handbrakes, are now widely used in various passenger and commercial vehicles. They achieve automatic parking and release of the vehicle through electronic control, greatly simplifying driver operation and improving vehicle convenience and safety, and have become a key feature of modern automobiles.

[0003] Currently, the most common electronic parking brake release control strategies in the industry are based on throttle signal triggering. A common approach is to preset different gradient ranges in the system; when the driver depresses the accelerator pedal to a set threshold corresponding to the gradient, the parking brake is immediately released. A more improved strategy determines the release timing by comparing the engine's current output torque with a preset torque threshold.

[0004] However, the aforementioned existing technologies have significant shortcomings in their computational models for determining parking brake release conditions. These methods typically only consider two basic factors: vehicle weight and road gradient, while neglecting many variables that have a crucial impact on vehicle starting dynamics.

[0005] Because the calculation model is overly simplified, the system cannot accurately determine the optimal timing for releasing the parking brake. The direct consequence is that two undesirable conditions can easily occur when the vehicle starts: first, releasing the brake too early or with insufficient driving force causes the vehicle to roll backward, posing a safety hazard; second, releasing the brake too late or with excessive driving force causes the vehicle to suddenly lurch forward, resulting in a jerking motion. These problems severely affect the smoothness and comfort of the ride, and also diminish the safety benefits that the EPB system should provide. Summary of the Invention

[0006] To address the above problems, the present invention aims to provide an electronic parking brake release control method and system based on CAN bus, which can automatically adjust the timing of vehicle brake release according to vehicle weight, slope and starting gear, thereby improving starting comfort, acceleration and safety.

[0007] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, embodiments of this application provide an electronic parking release control method based on a CAN bus, comprising the following steps: S1: Obtain the control status of the electronic parking system in real time from the CAN bus via the EPB controller. If it is in braking state, execute step S2. S2: Obtain brake status information and throttle opening information in real time through the EPB controller; determine whether the brake is released and the throttle opening is not equal to 0; if yes, proceed to step S3; if no, the electronic parking system maintains the braking state. S3: Obtain the slope value and vehicle weight information in real time through the EPB controller, and calculate the expected engine torque; determine whether the slope value is greater than or equal to the preset slope value; if yes, proceed to step S4; if no, proceed to step S5. S4: Calculate the net engine torque based on the actual engine torque and engine accessory torque; determine whether the net engine torque is greater than or equal to the expected engine torque; if yes, proceed to step S5; if no, proceed to step S2. S5: Obtain the current throttle opening information in real time through the EPB controller; determine whether the current throttle opening is greater than or equal to the preset throttle opening value; if yes, proceed to step S6; if no, proceed to step S2. S6: The timer built into the EPB controller keeps track of the time. When the timer is greater than or equal to the preset time interval, the EPB controller controls the electronic parking system to release the vehicle; otherwise, the timer continues to run.

[0008] In one optional implementation, the braking state includes an AutoHold service braking state and a parking braking state.

[0009] In an optional implementation, step S3 includes: The EPB controller stores the preset standard starting torque table, the first torque compensation table, and the second torque compensation table. The current gearbox ratio is obtained through the EPB controller, and the current gear ratio coefficient i is calculated. x ; The compensation value B for the desired starting torque under the current operating conditions is determined by the EPB controller based on the current operating conditions. Using formula T through the EPB controller Q =T B ×i x +B calculates the desired engine torque T required for the vehicle to start. Q Among them, T B The standard starting torque is obtained from the standard starting torque table.

[0010] In an optional implementation, the current speed ratio coefficient i x The calculation process is as follows: Select a starting gear ratio as the standard gear ratio, and let C = standard gear ratio; Get the current gear ratio i d ; Through formula Calculate the current speed ratio coefficient i x .

[0011] In an optional implementation, determining the compensation value B of the desired starting torque required under the current operating conditions via the EPB controller includes: when i x When the gear ratio is equal to the current gearbox ratio, B=0; when i x When the current gear ratio is greater than the current transmission speed ratio, the compensation value B is determined through the first torque compensation table; when i x When the gear ratio is less than the current gearbox ratio, the compensation value B is determined by the second torque compensation table.

[0012] In an optional implementation, determining the compensation value B of the desired starting torque required under the current operating conditions via the EPB controller includes: Get the current gear position D; When D=1, the compensation value B is determined by the first torque compensation table; when D=2, the compensation value B is determined by the second torque compensation table.

[0013] In one optional implementation, the standard starting torque table is a two-dimensional interpolation table of gradient, vehicle weight, and standard starting torque, which is used to determine the corresponding standard starting torque based on real-time gradient and vehicle weight information.

[0014] In an optional implementation, both the first torque compensation table and the second torque compensation table are two-dimensional interpolation tables for gradient, vehicle weight, and compensated starting torque. Both the first torque compensation table and the second torque compensation table are used to determine the corresponding compensated starting torque based on the real-time gradient value and vehicle weight information.

[0015] In an optional implementation, step S3 further includes: When the vehicle weight value obtained in real time through the EPB controller is equal to an invalid value, the EPB controller automatically calculates the actual vehicle weight and presets it as the default vehicle weight value.

[0016] In an optional implementation, calculating the net engine torque based on the actual engine torque and engine accessory torque includes: Engine net torque = actual engine torque - engine accessory torque.

[0017] Secondly, embodiments of this application also provide an electronic parking release control system based on a CAN bus, comprising: The information acquisition module is used to acquire, in real time from the CAN bus, the electronic parking system control status, brake status information, throttle opening information, gradient value, vehicle weight information, actual engine torque, engine accessory torque, current transmission gear, and current transmission ratio via the EPB controller; The calculation module is used to calculate the desired engine torque, calculate the actual vehicle weight, and calculate the net engine torque based on the actual engine torque and engine accessory torque through the EPB controller. The first judgment module is used to determine whether the brake is in the released state and the throttle opening is not equal to 0; The second judgment module is used to determine whether the slope value is greater than or equal to the preset slope value; The third judgment module is used to determine whether the net engine torque is greater than or equal to the expected engine torque. The fourth judgment module is used to determine whether the current throttle opening is greater than or equal to the preset throttle opening value; The electronic parking system release module is used to release the electronic parking system by controlling the EPB controller when the timer built into the EPB controller is greater than or equal to the preset time interval value.

[0018] As can be seen from the above technical solutions, the present invention has the following advantages: The electronic parking brake release control method based on the CAN bus provided in this application precisely controls the release of the electronic parking brake system by calculating in real time the desired engine torque required for successful vehicle start-up without rollback under the current operating conditions. Variables such as different gear ratios of the transmission and engine accessory torques are incorporated into the calculation of the engine net torque and desired torque. Furthermore, through vehicle powertrain calculations or empirical calibration methods, the effects of factors such as the rear axle ratio, engine transmission efficiency, and road friction resistance are considered in the calculation of the desired torque, preventing vehicle rollback on inclines and making vehicle start-up smoother and more comfortable. This method is applicable to vehicles with different configurations and saves costs. In addition, by preset throttle opening values ​​and preset time interval values, safety hazards caused by accidental accelerator pedal touch or erroneous CAN signal transmission leading to incorrect release of the electronic parking brake system are prevented.

[0019] This application ensures that the electronic parking brake system releases only under safe conditions through multiple condition checks. For example, it monitors brake status, throttle opening, gradient, and vehicle weight in real time, and requires the engine's net torque to reach a desired value when the gradient is steep, preventing the vehicle from rolling away unexpectedly on slopes. This rigorous safety logic reduces the risk caused by misoperation or system malfunction, enhancing overall driving safety.

[0020] This application integrates real-time data and dynamically calculates the desired torque, utilizing a standard starting torque table and compensation table to adapt to different driving conditions. For example, torque compensation is adjusted according to the transmission ratio and gear position, enabling the system to intelligently respond to various road conditions and load changes, ensuring smooth starts and improving the system's reliability and adaptability in different environments.

[0021] This application ensures the accuracy of parking release decisions by precisely calculating the desired engine torque and net engine torque, and then making real-time adjustments using two-dimensional interpolation tables (such as standard starting torque tables and compensation tables). This refined control avoids premature or delayed release, optimizes the vehicle start-up process, and improves the system's response speed and efficiency.

[0022] This application automates the parking brake release process, eliminating the need for manual operation of the parking brake. Release is triggered simply through conventional throttle and brake controls. A built-in timer further ensures consistent release timing, reducing driver intervention and making vehicle operation smoother and more intuitive, thus enhancing the overall driving experience.

[0023] This application utilizes the CAN bus to achieve efficient communication between the EPB controller and other vehicle systems, ensuring real-time data exchange and coordinated control. The method fully leverages the advantages of the CAN bus to quickly acquire information such as braking status and throttle opening, enabling rapid decision-making and response, reducing system complexity and cost, and improving the overall reliability of the vehicle system. Attached Figure Description

[0024] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A flowchart illustrating the electronic parking release control method based on CAN bus provided in this application.

[0026] Figure 2 A flowchart illustrating the method for obtaining vehicle weight information provided in this application.

[0027] Figure 3 A flowchart illustrating a method for calculating desired engine torque provided in this application.

[0028] Figure 4 A flowchart illustrating another method for calculating the desired engine torque provided in this application.

[0029] Figure 5A schematic diagram of the electronic parking release control system based on CAN bus provided in this application. Detailed Implementation

[0030] The various embodiments of this disclosure will be described more fully in the following detailed description of the specific steps of the CAN bus-based electronic parking release control method. This disclosure may have various embodiments, and adjustments and changes may be made therein. However, it should be understood that there is no intention to limit the various embodiments of this disclosure to the specific embodiments disclosed herein, but rather this disclosure should be understood to cover all adjustments, equivalents, and / or alternatives falling within the spirit and scope of the various embodiments of this disclosure.

[0031] The core of this invention is to provide an electronic parking brake release control method based on a CAN bus. In related technologies, the calculation model is overly simplified, causing the system to be unable to accurately determine the optimal timing for parking brake release. The direct consequence is that two undesirable conditions easily occur when the vehicle starts: first, release is too early or insufficient driving force causes the vehicle to roll backward, posing a safety hazard; second, release is too late or excessive driving force causes the vehicle to suddenly lurch forward, producing a jerking phenomenon. These problems seriously affect the smoothness and comfort of the ride, and also weaken the safety benefits that the EPB system should provide.

[0032] The electronic parking brake release control method based on the CAN bus provided by this invention integrates multi-dimensional information such as real-time monitoring of brake status, throttle opening, slope, and vehicle weight, and intelligently calculates the desired engine torque to achieve safe and reliable automatic parking brake release, effectively improving driving safety. It utilizes a dynamic adjustment mechanism of a standard torque gauge and a compensation gauge to enhance the system's adaptability to different slopes, loads, and transmission gear conditions, ensuring smooth vehicle start-up and precise control. Simultaneously, this method significantly simplifies driver operation through automated decision-making and execution, improving driving convenience and comfort. Finally, relying on the efficient data interaction of the CAN bus, it achieves coordinated control of the entire vehicle system, improving system response speed and overall reliability.

[0033] In the following, the terms “comprising” or “may include”, which may be used in various embodiments of this disclosure, indicate the presence of the disclosed functions, operations, or elements, and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in various embodiments of this disclosure, the terms “comprising,” “having,” and their cognates are intended only to indicate a particular feature, number, step, operation, element, component, or combination of the foregoing, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing, or the possibility of adding one or more combinations of the foregoing.

[0034] The technical solutions of the embodiments 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, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please see Figure 1 The diagram shown is a flowchart of an electronic parking brake release control method based on a CAN bus in a specific embodiment. The method includes the following steps: S1: Obtain the control status of the electronic parking system in real time from the CAN bus via the EPB controller. If it is in braking state, execute step S2.

[0036] In this application, the core function of the EPB controller is to integrate vehicle status information through the CAN bus and act as an intelligent decision center to dynamically coordinate the release of the parking brake. It calculates or acquires the vehicle weight in real time and accurately calculates the minimum expected torque required for a smooth start based on factors such as gradient and transmission ratio. By continuously comparing the actual available torque of the engine with this expected torque, it only performs the release at the critical point when the power is fully available, thereby eliminating the problems of slippage and jerking during start-up under traditional control strategies and achieving safe and smooth automatic start-up.

[0037] The electronic parking system control state can be either AutoHold service brake state or parking brake state.

[0038] S2: Obtain brake status information and throttle opening information in real time through the EPB controller; determine whether the brake is released and the throttle opening is not equal to 0; if yes, execute step S3; if no, the electronic parking system maintains the braking state.

[0039] S3: Obtain the slope value and vehicle weight information in real time through the EPB controller, and calculate the expected engine torque; determine whether the slope value is greater than or equal to the preset slope value; if yes, proceed to step S4; if no, proceed to step S5.

[0040] S4: Calculate the net engine torque based on the actual engine torque and engine accessory torque; determine whether the net engine torque is greater than or equal to the expected engine torque; if yes, proceed to step S5; if no, proceed to step S2.

[0041] Among them, the net engine torque = actual engine torque - engine accessory torque.

[0042] S5: Obtain the current throttle opening information in real time through the EPB controller; determine whether the current throttle opening is greater than or equal to the preset throttle opening value; if yes, proceed to step S6; if no, proceed to step S2.

[0043] S6: The timer built into the EPB controller keeps track of the time. When the timer is greater than or equal to the preset time interval, the EPB controller controls the electronic parking system to release the vehicle; otherwise, the timer continues to run.

[0044] It should be noted that, in this embodiment, the preset slope value in step S3, the preset throttle opening value in step S5, and the preset time interval value in step S6 can all be set based on actual experience or calibrated from actual working conditions.

[0045] In this embodiment, vehicle status information is integrated in real time via the CAN bus, enabling intelligent and safe release of the electronic parking brake. Based on multiple safety condition assessments, including precise calculations of slope, vehicle weight, and engine torque, it effectively prevents the risk of vehicle rollback, especially during hill starts. Through an intelligent torque compensation mechanism, the system can adapt to different operating conditions to ensure smooth starts. Simultaneously, this automatic release function significantly simplifies driver operation, improves driving convenience and comfort, and ultimately enhances the overall vehicle safety and reliability through coordinated control of various systems.

[0046] In one embodiment of the present invention, based on step S3, the following will provide a possible embodiment and describe its specific implementation in a non-limiting manner.

[0047] refer to Figure 2 As shown, this embodiment discloses a method for obtaining vehicle weight information, which uses an EPB controller to determine specific vehicle weight information through direct acquisition or calculation.

[0048] Specifically: when the vehicle weight value obtained by the EPB controller from the CAN bus is equal to an invalid value, the EPB controller automatically calculates the actual vehicle weight, which becomes the preset default vehicle weight value; when the vehicle weight value obtained by the EPB controller from the CAN bus is not equal to an invalid value, the obtained vehicle weight value is used as the real-time vehicle weight value. In other words, if vehicle weight information cannot be directly obtained, the EPB controller automatically calculates the actual vehicle weight as the obtained vehicle weight information; if vehicle weight information can be directly obtained, that information is used directly.

[0049] The vehicle weight information acquisition method provided in this embodiment effectively ensures that the electronic parking system obtains accurate vehicle weight data under various operating conditions through a dual guarantee mechanism combining direct acquisition and automatic calculation. When the vehicle weight value transmitted via the CAN bus is invalid, the system can automatically calculate the actual vehicle weight as a preset default value. This backup scheme ensures the reliability of key parameter acquisition. This flexible data acquisition strategy not only enhances the system's adaptability to different vehicle models and communication states but also provides a solid data foundation for accurate decision-making in electronic parking control, thereby improving the robustness and practicality of the entire control system.

[0050] In one embodiment of the present invention, based on step S3, the following will provide a possible embodiment and describe its specific implementation in a non-limiting manner.

[0051] refer to Figure 3 As shown in the figure, this embodiment discloses a method for calculating the desired engine torque, which specifically includes the following steps: S301: The EPB controller stores a preset standard starting torque table, a first torque compensation table, and a second torque compensation table. Depending on the different control strategies in step S3 or actual needs, more torque compensation tables can be saved in advance.

[0052] In this sub-step, the standard starting torque table is a two-dimensional interpolation table for gradient, vehicle weight, and standard starting torque. The standard starting torque table is used to determine the corresponding standard starting torque based on real-time gradient and vehicle weight information. The inputs to the standard starting torque table are gradient and vehicle weight, and the output is the standard starting torque. The standard starting torque value can be calculated from the entire vehicle powertrain or obtained through actual calibration.

[0053] In this sub-step, both the first torque compensation table and the second torque compensation table are two-dimensional interpolation tables for gradient, vehicle weight, and compensated starting torque. Both tables are used to determine the corresponding compensated starting torque based on real-time gradient and vehicle weight information. The inputs to both torque compensation tables are gradient and vehicle weight, and the output is the compensated starting torque. The compensated starting torque value can be calculated from the entire vehicle powertrain or obtained through actual calibration.

[0054] S302: Obtain the current gearbox speed ratio through the EPB controller and calculate the current speed ratio coefficient i x .

[0055] Wherein, the current speed ratio coefficient i x The calculation process is as follows: First, select a starting gear ratio as the standard gear ratio, and let C = standard gear ratio; then obtain the current gearbox gear ratio i. d Finally, through the formula Calculate the current speed ratio coefficient i x .

[0056] It should be noted that the standard gear ratio can be either the gear ratio of a commonly used starting gear, or a commonly used value calculated based on actual working conditions.

[0057] S303: The compensation value B of the expected torque required for starting under the current operating conditions is determined by the EPB controller based on the current operating conditions.

[0058] Specifically, when i x When the gear ratio is equal to the current gearbox ratio, B=0; when i x When the current gear ratio is greater than the current transmission speed ratio, the compensation value B is determined through the first torque compensation table; when i x When the gear ratio is less than the current gearbox ratio, the compensation value B is determined by the second torque compensation table.

[0059] S304: Using formula T via EPB controller Q =T B ×i x +B calculates the desired engine torque T required for the vehicle to start. Q Among them, T B The standard starting torque is obtained from the standard starting torque table.

[0060] In this embodiment, by combining a standard starting torque table with multiple sets of torque compensation tables and introducing a dynamic adjustment mechanism for the speed ratio coefficient, precise adaptation to different gradients, vehicle weights, and transmission operating conditions is achieved. This method utilizes a two-dimensional interpolation table to determine the base torque and compensation value based on real-time parameters, then adjusts the speed ratio coefficient proportionally to ultimately synthesize the precise desired torque. This hierarchical calculation strategy significantly improves the accuracy and adaptability of starting torque control, ensuring that the vehicle obtains optimal starting power under various load and gradient conditions, while also enhancing the system's robustness and control precision.

[0061] In one embodiment of the present invention, based on step S3, the following will provide a possible embodiment and describe its specific implementation in a non-limiting manner.

[0062] refer to Figure 4 As shown, this embodiment discloses another method for calculating the desired engine torque, which specifically includes the following steps: S311: Stores preset standard starting torque tables, first torque compensation tables, second torque compensation tables, third torque compensation tables, fourth torque compensation tables, and fifth torque compensation tables via the EPB controller.

[0063] In this sub-step, the standard starting torque table is a two-dimensional interpolation table for gradient, vehicle weight, and standard starting torque. The standard starting torque table is used to determine the corresponding standard starting torque based on real-time gradient and vehicle weight information. The inputs to the standard starting torque table are gradient and vehicle weight, and the output is the standard starting torque. The standard starting torque value can be calculated from the entire vehicle powertrain or obtained through actual calibration.

[0064] In this sub-step, the first, second, third, fourth, and fifth torque compensation tables are all two-dimensional interpolation tables related to gradient, vehicle weight, and compensated starting torque. These tables are used to determine the corresponding compensated starting torque based on real-time gradient and vehicle weight information. The inputs to the five torque compensation tables are gradient and vehicle weight, and the output is the compensated starting torque. The compensated starting torque value can be calculated from the entire vehicle powertrain or obtained through actual calibration.

[0065] S312: Obtain the current gearbox speed ratio through the EPB controller and calculate the current speed ratio coefficient i x .

[0066] Wherein, the current speed ratio coefficient i x The calculation process is as follows: First, select a starting gear ratio as the standard gear ratio, and let C = standard gear ratio; then obtain the current gearbox gear ratio i. d Finally, through the formula Calculate the current speed ratio coefficient i x .

[0067] It should be noted that the standard gear ratio can be either the gear ratio of a commonly used starting gear, or a commonly used value calculated based on actual working conditions.

[0068] S313: The compensation value B of the expected torque required for starting under the current operating conditions is determined by the EPB controller based on the current operating conditions.

[0069] Specifically, the current gearbox gear D is first obtained; when D=1, the compensation value B is determined using the first torque compensation table; when D=2, the compensation value B is determined using the second torque compensation table; when D=3, the compensation value B is determined using the third torque compensation table; when D=4, the compensation value B is determined using the fourth torque compensation table; and when D=-1, the compensation value B is determined using the fifth torque compensation table. This process can cover all possible starting gears.

[0070] S314: Using formula T via the EPB controller Q =T B ×ix +B calculates the desired engine torque T required for the vehicle to start. Q Among them, T B The standard starting torque is obtained from the standard starting torque table.

[0071] In this embodiment, by establishing a complete database including a standard starting torque table and five specialized torque compensation tables, and combining intelligent gearbox gear identification and dynamic calculation of gear ratio coefficients, precise torque control covering all operating conditions is achieved. The system can obtain a basic torque value through two-dimensional interpolation based on real-time slope and vehicle weight parameters, and automatically match the corresponding compensation table to obtain compensation values ​​according to the specific gear, ultimately synthesizing the optimal desired torque through a formula. This multi-table collaborative mechanism based on gear segmentation significantly improves the torque control accuracy under different starting conditions, ensuring that the vehicle receives precisely matched power output when starting in all gears, including reverse, effectively enhancing the system's adaptability and control reliability.

[0072] like Figure 5 As shown, the following are embodiments of the electronic parking release control system based on the CAN bus provided in this disclosure. This system and the electronic parking release control method based on the CAN bus in the above embodiments belong to the same inventive concept. For details not described in detail in the embodiments of the electronic parking release control system based on the CAN bus, please refer to the embodiments of the electronic parking release control method based on the CAN bus described above.

[0073] An electronic parking release control system based on CAN bus includes: an information acquisition module, a calculation module, a first judgment module, a second judgment module, a third judgment module, a fourth judgment module, and an electronic parking system release module.

[0074] The information acquisition module is used to acquire, in real time from the CAN bus, the electronic parking system control status, brake status information, throttle opening information, gradient value, vehicle weight information, actual engine torque, engine accessory torque, current transmission gear, and current transmission ratio via the EPB controller.

[0075] The calculation module is used to calculate the desired engine torque, calculate the actual vehicle weight, and calculate the net engine torque based on the actual engine torque and engine accessory torque through the EPB controller.

[0076] The first judgment module is used to determine whether the brake is released and the throttle opening is not equal to 0.

[0077] The second judgment module is used to determine whether the slope value is greater than or equal to the preset slope value.

[0078] The third judgment module is used to determine whether the net engine torque is greater than or equal to the expected engine torque.

[0079] The fourth judgment module is used to determine whether the current throttle opening is greater than or equal to the preset throttle opening value.

[0080] The electronic parking system release module is used to release the electronic parking system by controlling the EPB controller when the timer built into the EPB controller is greater than or equal to the preset time interval value.

[0081] The electronic parking brake release control system based on the CAN bus provided in this embodiment integrates vehicle status data in real time through the CAN bus, realizing intelligent and safe release of the electronic parking brake. Based on multiple safety condition judgments, the system effectively prevents unexpected vehicle movement under various operating conditions by accurately calculating the matching relationship between slope, vehicle weight, and engine torque. Its intelligent torque adaptive mechanism ensures smooth starts, while automated operation significantly improves driving convenience. Ultimately, through the coordinated control of the entire vehicle system, the safety and reliability of the vehicle are comprehensively enhanced.

[0082] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for electronic parking brake release control based on CAN bus, characterized in that, Includes the following steps: S1: Obtain the control status of the electronic parking system in real time from the CAN bus via the EPB controller. If it is in braking state, execute step S2. S2: Obtain brake status information and throttle opening information in real time through the EPB controller; determine whether the brake is released and the throttle opening is not equal to 0; if yes, proceed to step S3; if no, the electronic parking system maintains the braking state. S3: Obtain the slope value and vehicle weight information in real time through the EPB controller, and calculate the expected engine torque; determine whether the slope value is greater than or equal to the preset slope value; if yes, proceed to step S4; if no, proceed to step S5. S4: Calculate the net engine torque based on the actual engine torque and engine accessory torque; determine whether the net engine torque is greater than or equal to the expected engine torque; if yes, proceed to step S5; if no, proceed to step S2. S5: Obtain the current throttle opening information in real time through the EPB controller; determine whether the current throttle opening is greater than or equal to the preset throttle opening value; if yes, proceed to step S6; if no, proceed to step S2. S6: The timer built into the EPB controller keeps track of the time. When the timer is greater than or equal to the preset time interval, the EPB controller controls the electronic parking system to release the vehicle; otherwise, the timer continues to run.

2. The electronic parking brake release control method based on CAN bus according to claim 1, characterized in that, The braking states include the AutoHold service braking state and the parking braking state.

3. The electronic parking brake release control method based on CAN bus according to claim 1, characterized in that, Step S3 includes: The EPB controller stores the preset standard starting torque table, the first torque compensation table, and the second torque compensation table. The current gearbox ratio is obtained through the EPB controller, and the current gear ratio coefficient i is calculated. x ; The compensation value B for the desired starting torque under the current operating conditions is determined by the EPB controller based on the current operating conditions. Using formula T through the EPB controller Q =T B ×i x +B calculates the desired engine torque T required for the vehicle to start. Q Among them, T B The standard starting torque is obtained from the standard starting torque table.

4. The electronic parking brake release control method based on CAN bus according to claim 3, characterized in that, The current speed ratio coefficient i x The calculation process is as follows: Select a starting gear ratio as the standard gear ratio, and let C = standard gear ratio; Get the current gear ratio i d ; Through formula Calculate the current speed ratio coefficient i x .

5. The electronic parking brake release control method based on CAN bus according to claim 3, characterized in that, The step of determining the compensation value B of the desired starting torque required under the current operating conditions through the EPB controller includes: when i x When i equals the current gearbox ratio, B=0; when i x When the current gear ratio is greater than the current transmission speed ratio, the compensation value B is determined through the first torque compensation table; when i x When the gear ratio is less than the current gearbox ratio, the compensation value B is determined by the second torque compensation table.

6. The electronic parking brake release control method based on CAN bus according to claim 3, characterized in that, The step of determining the compensation value B of the desired starting torque required under the current operating conditions through the EPB controller includes: Get the current gear position D; When D=1, the compensation value B is determined by the first torque compensation table; when D=2, the compensation value B is determined by the second torque compensation table.

7. The electronic parking brake release control method based on CAN bus according to claim 5 or 6, characterized in that, The standard starting torque table is a two-dimensional interpolation table for gradient, vehicle weight, and standard starting torque. The standard starting torque table is used to determine the corresponding standard starting torque based on real-time gradient and vehicle weight information. Both the first torque compensation table and the second torque compensation table are two-dimensional interpolation tables for slope, vehicle weight, and compensated starting torque. Both the first torque compensation table and the second torque compensation table are used to determine the corresponding compensated starting torque based on the real-time slope value and vehicle weight information.

8. The electronic parking brake release control method based on CAN bus according to claim 3, characterized in that, Step S3 further includes: When the vehicle weight value obtained in real time through the EPB controller is equal to an invalid value, the EPB controller automatically calculates the actual vehicle weight and presets it as the default vehicle weight value.

9. The electronic parking brake release control method based on CAN bus according to claim 3, characterized in that, The calculation of the engine net torque based on the actual engine torque and engine accessory torque includes: Engine net torque = actual engine torque - engine accessory torque.

10. An electronic parking release control system based on a CAN bus, characterized in that, The system employs the electronic parking release control method based on CAN bus as described in any one of claims 1 to 9; The system includes: The information acquisition module is used to acquire, in real time from the CAN bus, the electronic parking system control status, brake status information, throttle opening information, gradient value, vehicle weight information, actual engine torque, engine accessory torque, current transmission gear, and current transmission ratio via the EPB controller; The calculation module is used to calculate the desired engine torque, calculate the actual vehicle weight, and calculate the net engine torque based on the actual engine torque and engine accessory torque through the EPB controller. The first judgment module is used to determine whether the brake is in the released state and the throttle opening is not equal to 0; The second judgment module is used to determine whether the slope value is greater than or equal to the preset slope value; The third judgment module is used to determine whether the net engine torque is greater than or equal to the expected engine torque. The fourth judgment module is used to determine whether the current throttle opening is greater than or equal to the preset throttle opening value; The electronic parking system release module is used to release the electronic parking system by controlling the EPB controller when the timer built into the EPB controller is greater than or equal to the preset time interval value.

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