A fuel vehicle braking jerk prevention and control system and a control method thereof

Abstract

The present application belongs to the field of automobile power and control technology, and in particular to a fuel vehicle braking jerk prevention and control system and a control method thereof. The system comprises a vehicle body posture detection module, a vehicle body posture decoupling module, a pedal stroke and acceleration detection module, a vehicle speed monitoring module, a front obstacle detection module, a control decision module, and a communication and execution module. Data interaction is achieved between the modules through a CAN bus, and the respective data is sent to the control decision module. After calculation, the control decision module sends control instructions to the communication and execution module through the CAN bus. The present application introduces a self-learning mechanism, which dynamically optimizes key parameters such as acceleration threshold, pedal stroke threshold, and vehicle speed trigger conditions based on driving history data, so that the control strategy gradually adapts to the operating habits of different drivers, achieving personalized braking smooth control effect.

Description

Technical Field

[0001] This invention relates to the field of automotive power and control technology, specifically to a braking jerking prevention system and control method for fuel-powered vehicles. Background Technology

[0002] Existing gasoline-powered vehicles generally exhibit a noticeable "jerkiness" during deceleration to a standstill, especially at the lower speeds (below 5 km / h). This phenomenon primarily stems from a mismatch between the response of the power transmission system and the braking system. This problem is prevalent in vehicles with automatic transmissions (AT).

[0003] This phenomenon mainly involves the following specific issues:

[0004] (1) The transmission shift logic is lagging, and the vehicle remains in a lower gear at low speed, which causes the engine drag force and braking force to overlap, resulting in an impact.

[0005] (2) At the moment when the vehicle is about to stop (the speed approaches 0), the coefficient of friction between the brake disc and the brake pad changes abruptly from the coefficient of dynamic friction to the coefficient of static friction, resulting in a sudden surge in braking torque, which in turn causes the "nodding" phenomenon due to the excessive rate of change of acceleration.

[0006] (3) Significant differences in driver operation and individual habits lead to instability in the braking process.

[0007] (4) Insufficient system judgment under complex working conditions such as slopes. Existing solutions mostly rely on fixed control mapping and lack adaptive and multi-sensor fusion mechanisms, and cannot effectively adjust to the driving habits of different drivers.

[0008] (5) End braking can cause unnecessary discomfort (motion sickness, physical fatigue, jerking) or even cause items inside the vehicle to fall, resulting in danger.

[0009] In order to achieve personalized smooth control based on different drivers, it is necessary to design an adaptive control system that can perceive multi-dimensional driving signals in real time and has the ability to learn, so as to achieve smoothness and comfort at the end of vehicle braking. Summary of the Invention

[0010] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0011] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0012] A braking jerking prevention system for a fuel-powered vehicle includes a vehicle posture detection module, a vehicle posture decoupling module, a pedal travel and acceleration detection module, a vehicle speed monitoring module, a forward obstacle detection module, a control decision module, and a communication and execution module. The modules interact with each other via a CAN bus and send their respective data to the control decision module. After calculation, the control decision module sends the control commands to the communication and execution module via the CAN bus.

[0013] Vehicle attitude detection module: provides basic data on vehicle dynamics and body attitude, and provides dual safety constraints of acceleration and slope for the control decision module;

[0014] Vehicle attitude decoupling module: used to obtain the comprehensive offset angle θ0 and the vehicle dynamic pitch angle θ body ;

[0015] Pedal travel and acceleration detection module: used to detect brake pedal travel and pedal depress angular velocity;

[0016] Vehicle speed monitoring module: used to acquire vehicle speed information in real time;

[0017] Forward obstacle detection module: Obtains the distance to obstacles ahead using millimeter-wave radar or a camera. ;

[0018] Control Decision Module: The core is the algorithm control logic unit, which integrates signals from various sensors, uses a weighted fusion algorithm to calculate the timing of system intervention, and outputs transmission control commands and braking force adjustment signals; it has a self-learning function, dynamically adjusting parameters based on different users' driving history data to achieve personalized and smooth control;

[0019] Control decision module and communication and execution module: Transmit decision signals to engine control unit and transmission control unit to realize clutch unloading control and braking force adjustment, delay control signals, and realize closed-loop control of the system.

[0020] As a preferred embodiment of the braking jerking prevention system for fuel-powered vehicles described in this invention, the vehicle posture detection module is responsible for detecting lateral acceleration. and the rate of change of acceleration With pitch angle If the lateral acceleration exceeds a threshold, indicating an emergency braking need from the driver, the system cannot intervene to ensure the vehicle brakes with the shortest distance and time. This is achieved through fusion calculations using accelerometer and gyroscope data.

[0021] Let the lateral acceleration threshold be The system's judgment logic is as follows: This is used to determine the safe acceleration threshold.

[0022] At that time, it was determined to be an emergency braking situation, and no coasting intervention was initiated;

[0023] When the intervention conditions are met, prepare to execute clutch unloading control;

[0024] in The self-learning threshold;

[0025] After moving average filtering:

[0026]

[0027] Let the rate of change of lateral acceleration be The system's decision logic is as follows: This is used to determine the threshold for the rate of change of acceleration.

[0028] At that time, it was determined to be an emergency braking, and no coasting intervention was initiated;

[0029] When the intervention conditions are met, prepare to execute clutch unloading control;

[0030] Where J is the self-learning threshold;

[0031] After moving average filtering:

[0032] ;

[0033] The results are temporarily stored and used by the vehicle attitude decoupling module to calculate the actual road slope.

[0034] As a preferred embodiment of the braking jerking prevention system for fuel-powered vehicles described in this invention, the method for obtaining the comprehensive offset angle θ0 is as follows: when the vehicle is stationary on a level road surface or a road surface with a known slope, the pitch angle of the vehicle body attitude detection module is collected over a period of time. IMU And calculate the average value, and then calculate θ0 based on the known road inclination angle;

[0035] When a vehicle is stationary on a level road surface, the road's angle of inclination is zero. Therefore:

[0036] ;

[0037] Where N: the number of pitch angle data collected by the vehicle attitude detection module during the static calibration process; θ IMU (i): Pitch angle of the vehicle attitude detection module at the i-th sampling time; θ0: Comprehensive offset angle formed by IMU installation error, installation reference error and vehicle static attitude deviation;

[0038] When the vehicle is stationary at a known slope angle θ k When the road surface is..., then:

[0039] .

[0040] As a preferred embodiment of the braking jerking prevention system for fuel-powered vehicles described in this invention, the vehicle body dynamic pitch angle θ body The calculation method is as follows: when the vehicle is equipped with front and rear suspension height sensors or vehicle height sensors, the dynamic pitch angle of the vehicle body is directly calculated from the change in front and rear vehicle height.

[0041] ;

[0042] Where: θ body h is the vehicle's dynamic pitch angle. f h represents the current front axle position height. r h represents the current rear axle position height. f0 h represents the front axle position height under static reference conditions of the vehicle. r0 The rear axle height is the vehicle's position height under static reference conditions; L is the vehicle's wheelbase, or the longitudinal distance between the front and rear height measurement reference points; h f h f0 h represents the change in height of the front body relative to a static reference. r h r0 This refers to the change in height of the rear vehicle body relative to a static reference.

[0043] The final road inclination angle is:

[0044] ;

[0045] Obtained by the above method road The system's overall judgment logic is used to determine the vehicle's slope status:

[0046] When going uphill, the system does not intervene, and the driver's own operation is used to brake the vehicle to 0 km / h;

[0047] When going downhill, the system does not intervene, and the driver's own operation is used to brake the vehicle to 0 km / h;

[0048] Only when When the system intervenes, the clutch performs unloading control, completing one smooth control cycle;

[0049] and The initial value of the system is taken as 1°~2°;

[0050] The system adjusts through learning algorithms : so as to ensure that the speed decreases to the regulation index within a short time, and avoid the "vehicle rolling" phenomenon after clutch unloading control.

[0051] As a preferred solution of the brake jolt prevention and control system for fuel vehicles according to the present invention, the brake pedal travel and the pedal stepping angular velocity are detected by a displacement sensor installed on the brake pedal; when the pedal travel > N%, the pedal stepping angular velocity > , the system determines that it is an emergency or forced braking, and taking safety as the first goal, the vehicle is braked to standstill quickly, and clutch unloading control does not intervene; when the travel < N%, the pedal stepping speed < , the system intervenes to execute the clutch unloading control strategy; N is 5%-8%, is 0.1rad / s, and the pedal travel and acceleration detection module is configured to determine whether it is an emergency braking situation.

[0052] As a preferred solution of the brake jolt prevention and control system for fuel vehicles according to the present invention, a Hall sensor is used to acquire vehicle speed information in real time; when the speed is greater than a set threshold , to ensure safety, the vehicle is still in the braking stage, and the braking force is maintained; when the speed is less than the set threshold , the system intervenes in clutch unloading control:

[0053] , normal braking; , the system intervenes in the clutch unloading control logic;

[0054] wherein the initial value is set to 3-5km / h, and is adaptively adjusted according to driving history. For stable judgment, first-order low-pass filtering is adopted for vehicle speed data; the system maintains smooth coasting in a stable stage, and automatically increases the braking force when a significant increase in speed is detected.

[0055] As a preferred solution of the brake jolt prevention and control system for fuel vehicles according to the present invention, when the distance is less than a safety threshold , braking is maintained; when the distance is greater than , the clutch unloading control of the system is allowed.

[0056] As a preferred solution of the brake jolt prevention and control system for fuel vehicles according to the present invention, the execution flow of the control decision module and the communication and execution module is as follows:

[0057] the engine control unit receives the clutch unloading control command and controls the clutch to gradually disengage;

[0058] The transmission control unit coordinates and controls the engine drag torque according to the target deceleration requirement to avoid sudden changes in engine drag torque;

[0059] The body controller feeds forward the hydraulic braking force based on the clutch disengagement state and the estimated engine drag torque. It briefly maintains or appropriately increases the braking pressure at the moment of clutch disengagement to compensate for the decrease in total braking force caused by the disappearance of engine drag torque.

[0060] When the vehicle deceleration returns to a stable state and the vehicle speed approaches 0, the body controller gradually releases the hydraulic braking pressure according to the set slope, so that the vehicle stops smoothly.

[0061] If ABS intervention, hill start conditions, emergency braking, or increased driver braking intent are detected, the system immediately disengages clutch unloading control and restores normal braking control and transmission mode.

[0062] A method for controlling braking jerking in a gasoline-powered vehicle includes:

[0063] System initialization and status monitoring: After the vehicle is powered on and started, the system enters the initialization state. Each sensor module begins to collect the vehicle's attitude, speed, brake pedal travel and distance to obstacles in front in real time. During this stage, the system only monitors and caches data and does not output any control commands to ensure that the original vehicle control system operates completely according to the established logic.

[0064] Safety condition prediction:

[0065] When the system detects that the driver has pressed the brake pedal at any time, and the brake pedal travel and pedal depressing angular velocity exceed the corresponding threshold, or when ABS and ESP are activated, the system immediately starts the safety condition judgment logic. The system stops or does not intervene and resumes the normal braking and transmission logic. This mechanism is independent of the main logic and has the highest priority.

[0066] First, determine the vehicle speed. If the speed is too high, the risk is the greatest. Use the threshold speed as the judgment indicator.

[0067] Acceleration, rate of change of acceleration, road gradient 1. Check if the distance to the obstacle in front exceeds the set threshold. If the value of the corresponding module exceeds the corresponding threshold, it is determined to be a normal braking condition. Normally, the driver controls the braking by foot pedal and the system does not intervene.

[0068] Braking end stage identification process: Under the premise that safety conditions are met, the system continuously monitors the vehicle speed change. When the vehicle speed is lower than the set threshold and the deceleration change is stable, and the brake pedal is in a light pressing or slow release state, the system determines that the vehicle has entered the braking end stage, and the driver's goal is to stop smoothly.

[0069] Clutch unloading control execution: At the end of the braking phase, the system sends a clutch unloading control command to the transmission control unit to gradually separate the power transmission and eliminate the engine drag force. At the same time, the system gradually releases the braking pressure according to the vehicle speed decay curve, allowing the vehicle to coast smoothly with natural deceleration until it stops. Throughout the process, the system monitors the vehicle speed, acceleration and braking status in parallel.

[0070] Real-time safety reversal and abnormal handling: During the braking process, if abnormal increase in vehicle speed, driver use of brake pedal or increased braking, or intervention of ABS or ESP system are detected, the system will immediately terminate clutch unloading control and restore the original braking and transmission logic.

[0071] Parking completion and system reset: When the vehicle speed drops to 0km / h and remains stable, the system exits the active control state, completing a complete braking jerk control process. At the same time, the braking data is stored for subsequent parameter self-learning and optimization adjustment, providing a control strategy that is more in line with driving habits for subsequent braking processes.

[0072] As a preferred embodiment of the braking jerking control method for fuel vehicles described in this invention, the system follows three basic principles during operation: safety priority, end-of-pipe intervention, and minimum control intervention. The system only intervenes to ensure vehicle safety, the driver's braking intention is clear, and the vehicle is in the low-speed braking end stage. At any moment when the system intervenes, if the brake pedal or accelerator pedal is detected to be depressed, the clutch unloading control system stops intervening in a very short time.

[0073] Compared with the prior art, the beneficial effects of the present invention are: significantly reducing the jerkiness at the end of braking and improving ride comfort. The present invention effectively eliminates the instantaneous impact caused by the superposition of engine drag force and braking force by introducing multi-sensor fusion judgment and progressive control strategy at the end of low-speed braking of the vehicle, so that the vehicle can glide to a stop with continuous and smooth deceleration, significantly improving the jerkiness at the end of braking and improving ride comfort.

[0074] This system achieves accurate recognition of driving intentions, enhancing the intelligence of driving. It integrates vehicle acceleration, pedal travel, vehicle speed, tilt angle, and information about the surrounding environment to analyze and judge the driver's braking behavior in real time. It can effectively distinguish between different driving intentions, such as emergency braking and smooth stopping, and intervenes only under appropriate conditions, thus avoiding false triggering and excessive intervention, and improving the system's intelligence level.

[0075] It supports adaptive adjustment of thresholds and other parameters, and can learn from drivers to meet the needs of different driving habits. The system introduces a self-learning mechanism, which can dynamically optimize key parameters such as acceleration threshold, pedal travel threshold, and vehicle speed triggering conditions based on driving history data, so that the control strategy gradually adapts to the operating habits of different drivers and achieves personalized braking smooth control.

[0076] Reduce mechanical shock and energy consumption, and improve the service life of components. By eliminating unnecessary power drag and sudden braking force at the end of the braking process, the instantaneous impact load on the transmission, clutch and braking system is reduced, thereby effectively reducing mechanical wear and energy loss and extending the service life of related components.

[0077] The system has a simple structure and logic, and can be applied to civilian vehicles. This invention is based on existing vehicle sensors and onboard communication networks, requiring no complex modifications to the vehicle's powertrain system. The system has a clear structure, low implementation cost, and is suitable for various fuel-powered vehicle platforms, demonstrating good engineering feasibility and promising prospects for widespread application. Attached Figure Description

[0078] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the 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. Wherein:

[0079] Figure 1 This is a flowchart of the control logic of the present invention. Detailed Implementation

[0080] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0081] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0082] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0083] This invention uses multi-source sensor data fusion and adaptive learning mechanisms to recognize the driver's driving intentions and dynamically adjust the braking strategy at the end of the braking process. During the process of braking the vehicle from low speed to a standstill, it can dynamically adjust the transmission state by recognizing the driving intentions and using algorithms to judge multimodal constraints, thereby preventing the "jerk" phenomenon caused by excessive acceleration change rate (Jerk) at the end of the braking process.

[0084] Specifically, a braking jerking prevention system for gasoline-powered vehicles consists of seven main modules: an Information Measurement Unit (IMU) module, a vehicle attitude decoupling module, a pedal travel and acceleration detection module, a vehicle speed monitoring module, a forward obstacle detection module, a control decision module, and a communication and execution module. These modules interact via a CAN (Controller Area Network) bus, forming a closed-loop control system. They send their respective data (such as attitude angle, speed, and pedal travel information) to the control decision module via the CAN bus. The decision module then calculates the data and sends control commands to the execution module via the CAN bus.

[0085] Vehicle attitude detection module (IMU): The IMU module is responsible for detecting lateral acceleration. and the rate of change of acceleration With pitch angle If the acceleration exceeds a threshold, the driver may require emergency braking. In this case, the system cannot intervene to ensure the vehicle brakes with the shortest distance and time, avoiding accidents. This is achieved through calculations using a fusion of accelerometer and gyroscope readings.

[0086] Let the lateral acceleration threshold be The system's judgment logic is as follows: This is used to determine the safe acceleration threshold.

[0087] At that time, it was determined to be an emergency braking, and no coasting intervention was initiated; When the intervention conditions are met, prepare to execute clutch unloading control.

[0088] in The system uses a self-learning threshold with an initial value of 1.5 m / s². After analyzing different braking cases of drivers, a safe braking acceleration threshold is obtained.

[0089] After moving average filtering:

[0090] ;

[0091] Let the rate of change of lateral acceleration be ( The system's decision logic is as follows: (This is used to determine the threshold for the rate of change of acceleration.)

[0092] At that time, it was determined to be an emergency braking, and no coasting intervention was initiated; When the intervention conditions are met, the system prepares to execute clutch unloading control. Here, J is the self-learning threshold, with an initial system value of 1.5 m / s. 3 .

[0093] After moving average filtering:

[0094] ;

[0095] Pitch angle The results are temporarily stored and used by the attitude decoupling module to calculate the actual road slope.

[0096] In summary, the IMU module provides basic data on vehicle dynamics and body attitude, and provides the decision-making module with dual safety constraints of acceleration and gradient.

[0097] Vehicle attitude decoupling module: Vehicle attitude detection module measured by IMU IMU Mixed road slope road IMU installation error and vehicle static attitude combined offset angle The angles caused by changes in vehicle body posture during acceleration and deceleration. body The changes in vehicle attitude caused by braking, IMU installation errors, and the vehicle's static attitude offset angle may be misinterpreted by the sensors as slope tilt.

[0098] A vehicle attitude decoupling module should be installed so that the system can calculate the IMU's own installation error and the vehicle's static attitude combined offset angle. The angles caused by changes in vehicle body posture during acceleration and deceleration. body Then, the angles are discarded from the total angles measured by the IMU. This allows us to obtain the actual road slope. body To avoid confusion in slope measurement results due to the presence of nodding angles.

[0099] (1) Acquisition of the overall offset angle θ0: The overall offset angle θ0 of the IMU installation and vehicle static attitude can be obtained through static calibration. Specifically, when the vehicle is stationary on a horizontal road or a road with a known slope, the pitch angle of the IMU is collected over a period of time and the average value is calculated. θ0 is then calculated based on the known road tilt angle.

[0100] When a vehicle is stationary on a level road surface, the road's angle of inclination is zero. Therefore:

[0101] ;

[0102] Where: N: the number of IMU pitch angle data collected during the static calibration process; θ IMU (i): IMU pitch angle at the i-th sampling time; θ0: Comprehensive offset angle formed by IMU installation error, installation reference error and vehicle static attitude deviation.

[0103] When the vehicle is stationary at a known slope angle θ k When calibrating a road surface with a known longitudinal inclination angle, then:

[0104] .

[0105] (2) Vehicle body dynamic pitch angle θ body Obtain: Vehicle dynamic pitch angle θ body This angle is used to characterize the pitch change caused by suspension compression, vehicle body nodding, or pitching during acceleration, braking, or forward / backward jerking. This angle is not part of the road slope itself and needs to be removed from the IMU pitch angle.

[0106] When the vehicle is equipped with front and rear suspension height sensors or vehicle height sensors, the dynamic pitch angle of the vehicle can be directly calculated from the change in front and rear vehicle height.

[0107] ;

[0108] Where: θ body h is the vehicle's dynamic pitch angle. f h represents the current front axle position height. r h represents the current rear axle position height. f0 h represents the front axle position height under static reference conditions of the vehicle. r0 The rear axle height is the vehicle's position height under static reference conditions; L is the vehicle's wheelbase, or the longitudinal distance between the front and rear height measurement reference points; h f h f0 h represents the change in height of the front body relative to a static reference. r h r0 This refers to the change in height of the rear vehicle body relative to a static reference.

[0109] When the vehicle brakes and "nods," the front-to-rear height difference changes; similarly, when the vehicle accelerates and pitches up or experiences front-to-rear bumps, this height difference also changes. This formula allows the dynamic pitch angle caused by changes in vehicle attitude to be decoupled from the IMU pitch angle. The final road tilt angle is:

[0110] ;

[0111] Obtained by the above method road(uphill slope angle is taken as positive, downhill slope angle is taken as negative) is used to judge the vehicle gradient state, and the overall judgment logic of the system is:

[0112] (uphill angle threshold), when the vehicle is going uphill, the system does not intervene, and the driver's own operation is used to brake the vehicle to 0km / h;

[0113] , when the vehicle is going downhill, the system does not intervene, and the driver's own operation is used to brake the vehicle to 0km / h.

[0114] Only when , the system intervenes, the clutch performs unloading control, and a smooth control is completed once.

[0115] and take the initial system value of 1°~2°.

[0116] The system adjusts : taking reducing the speed to zero in a short time as the adjustment index, so as to avoid the "vehicle rolling" phenomenon after clutch unloading control. Due to different tire friction, different road conditions, different vehicle loads, wind and other reasons, values will not be completely the same.

[0117] Pedal detection module: a displacement sensor installed on the brake pedal is used to detect the brake pedal travel and pedal stepping angular velocity in real time.

[0118] When the pedal travel > N%, the pedal stepping angular velocity > , the system judges that it is an emergency or forced braking. Taking ensuring safety as the first goal, the vehicle is braked to standstill as quickly as possible, and clutch unloading control does not intervene; when the travel < N%, the pedal stepping speed < the system can intervene to implement the clutch unloading control strategy.

[0119] N is 5%-8%, takes 0.1rad / s, which can be gradually learned, optimized and adjusted according to different driving habits of different drivers later. This module is used to judge whether it is an emergency braking situation.

[0120] Vehicle speed monitoring module: a Hall sensor is used to obtain vehicle speed information in real time. When the speed is greater than the set threshold , to ensure safety, the vehicle is still in the braking phase and maintains the braking force; when the speed is less than the set threshold , the system intervenes in clutch unloading control:

[0121] , normal braking; At this time, the system intervenes in the clutch unloading control logic.

[0122] in The initial speed is set to 3-5 km / h and is adaptively adjusted based on driving history. For stability assessment, the vehicle speed data uses a first-order low-pass filter. The system maintains smooth coasting during steady-state driving and automatically increases braking force when a significant increase in speed is detected (such as inertial acceleration downhill).

[0123] Forward obstacle detection module: Obtains the distance to obstacles ahead using millimeter-wave radar or a camera. When the distance is less than the safety threshold When the distance is greater than 100 km, maintain braking; when the distance is greater than 100 km, maintain braking. At this time, the system clutch unloads control.

[0124] Control Decision Module: The core of this module is the algorithmic control logic unit. It integrates signals from various sensors and uses a weighted fusion algorithm to calculate the system's intervention timing, outputting transmission control commands and braking force adjustment signals. This module has a self-learning function, dynamically adjusting parameters based on different users' driving history data to achieve personalized, smooth control.

[0125] Communication Interface and Control Execution Module: This module transmits decision signals to the Engine Control Unit (TCU) and Transmission Control Unit (ECU) to achieve clutch unloading control and braking force adjustment. Control signal delay enables closed-loop system control.

[0126] The execution process is as follows:

[0127] (1) The TCU receives the clutch unloading control command and controls the clutch to gradually disengage;

[0128] (2) The ECU coordinates and controls the engine drag torque according to the target deceleration requirement to avoid sudden changes in engine drag torque;

[0129] (3) The BCM feeds forward the hydraulic braking force based on the clutch disengagement state and the estimated value of the engine reverse drag torque. It briefly maintains or appropriately increases the braking pressure at the moment of clutch disengagement to compensate for the decrease in total braking force caused by the disappearance of the engine reverse drag torque.

[0130] (4) When the vehicle deceleration returns to a stable state and the vehicle speed approaches 0, the BCM will gradually release the hydraulic braking pressure according to the set slope to bring the vehicle to a smooth stop.

[0131] (5) If ABS intervention, hill start conditions, emergency braking, or increased driver braking intention are detected, the system will immediately disengage clutch unloading control and restore normal braking control and transmission mode.

[0132] The present invention also provides a method for controlling braking jerking in a fuel-powered vehicle, comprising:

[0133] Overall Implementation Principles: This system operates according to three basic principles: safety first, end-of-pipe intervention, and minimal control intervention. The system intervenes only when vehicle safety is ensured, the driver's braking intention is clear, and the driver is in the final stage of low-speed braking, avoiding interference with the normal braking process and driving habits, thereby improving braking smoothness while ensuring safety. At any moment the system intervenes, if the brake or accelerator pedal is detected to be depressed, the clutch unloading control system should cease intervention within a very short time.

[0134] System initialization and status monitoring process: After the vehicle is powered on and started, the system enters the initialization state. Each sensor module begins to collect information such as vehicle attitude, speed, brake pedal travel, and distance to obstacles ahead in real time. During this stage, the system only monitors and buffers data, and does not output any control commands, ensuring that the original vehicle control system operates entirely according to the predetermined logic.

[0135] Safety condition prediction process:

[0136] (1) When the system detects that the driver has pressed the brake pedal at any time, and the brake pedal travel and pedal depressing angular velocity exceed the corresponding threshold, or when ABS (anti-lock braking system) and ESP (anti-slip system) are activated, the system immediately initiates the safety condition judgment logic, stops or does not intervene, and restores the normal braking and transmission logic. This mechanism is independent of the main logic and has the highest priority.

[0137] (2) First, determine the vehicle speed. If the speed is too high, the risk is the greatest, so speed is the primary indicator to be determined. Use the threshold speed as the judgment indicator, see the vehicle speed detection module for details.

[0138] (3) Acceleration, rate of change of acceleration (Jerk), road gradient 1. Check if the distance to the obstacle in front exceeds the set threshold. If the value of the corresponding module exceeds the corresponding threshold, it is determined to be a normal braking condition. Normally, the driver controls the braking by foot pedal and the system does not intervene. See the corresponding module for details.

[0139] End-of-Braking Phase Recognition Process: Under the premise that safety conditions are met, the system continuously monitors changes in vehicle speed. When the vehicle speed is below a set threshold and the deceleration changes smoothly, and the brake pedal is in a lightly pressed or slowly released state, the system determines that the vehicle has entered the end-of-braking phase, and the driver's goal is to stop smoothly.

[0140] Clutch unloading control execution process: At the end of braking, the system sends a clutch unloading control command to the transmission control unit to gradually disengage power transmission and eliminate engine drag. Simultaneously, the system gradually releases braking pressure according to the vehicle speed decay curve, allowing the vehicle to smoothly coast to a stop at natural deceleration. Throughout the entire process, the system monitors vehicle speed, acceleration, and braking status in parallel to ensure stable and reliable control.

[0141] Real-time safety rollback and anomaly handling process: During the braking process, if abnormal increases in vehicle speed are detected, the driver uses the brake pedal or increases braking, or the ABS or ESP system intervenes, the system immediately terminates clutch unloading control, restores the original braking and transmission logic, and prioritizes vehicle safety.

[0142] Parking Completion and System Reset: When the vehicle speed drops to 0 km / h and remains stable, the system exits active control mode, completing a full braking jerk control process. Simultaneously, the braking data is stored for subsequent parameter self-learning and optimization adjustments, providing a control strategy more suited to driving habits for future braking processes.

[0143] Example:

[0144] Example 1: Overall hardware configuration and connection relationship of the system.

[0145] This embodiment provides a braking jerking prevention system for gasoline-powered vehicles, applied to gasoline-powered passenger vehicles equipped with hydraulic automatic transmissions (AT). The system includes a vehicle posture detection module, a vehicle posture decoupling module, a pedal detection module, a vehicle speed monitoring module, a forward obstacle detection module, a control decision module, and a communication interface and control execution module. These modules are interconnected via an onboard CAN bus to form a closed-loop control system.

[0146] (1) Vehicle attitude detection module: A six-axis IMU (three-axis accelerometer and three-axis gyroscope) is used, which is installed near the center of gravity of the vehicle body, with a sampling frequency of 100Hz, and outputs longitudinal deceleration a. t , rate of change of acceleration J t and pitch angle θ IMU The original signal is filtered by an n=10-point moving average, i.e., a t =(1 / n)·Σa i J t =(1 / n)·ΣJ i To suppress random road surface disturbances and sensor noise.

[0147] (2) Pedal detection module: A non-contact angular displacement sensor is installed at the hinge of the brake pedal to output the pedal travel (expressed as a percentage of full travel) and the pedal angular velocity in real time, which is used to determine whether it is an emergency or forced braking.

[0148] (3) Vehicle speed monitoring module: the vehicle speed v is acquired by a Hall sensor arranged on the transmission output shaft or wheel shaft t , and after first-order low-pass filtering, v t =v t -1+β(v raw -v t -1) (β is 0.2) to stabilize the determination of the low-speed section.

[0149] (4) Forward obstacle detection module: a 77GHz millimeter-wave radar (fused with a forward-looking camera when necessary) is used to measure the longitudinal distance a of the forward obstacle.

[0150] (5) Vehicle body attitude decoupling module: one suspension height (vehicle body height) sensor is arranged at each of the front and rear axles, and outputs the front axle height h f and the rear axle height h r , which is used for calculating the dynamic pitch angle of the vehicle body θ body and the real road slope θ road to use.

[0151] (6) Control decision module: the on-board domain controller (MCU) carries the weighted fusion algorithm and the self-learning algorithm, comprehensively calculates the intervention timing based on the signals of each sensor, and outputs the clutch unloading and braking force regulation instructions.

[0152] (7) Communication interface and control execution module: communicates with the transmission control unit (TCU), the engine control unit (ECU / EMS), the body control module and the hydraulic braking unit (BCM / ESC) respectively via the CAN bus; the TCU controls clutch disengagement, the ECU coordinates engine drag torque, and the BCM / ESC regulates hydraulic braking force.

[0153] Example 2: Complete control process for smooth stopping at the end of low-speed braking on a flat road surface.

[0154] This embodiment is combined with the attached Figure 1 describes a typical complete smooth stop control process. Initial conditions: the vehicle is traveling on a flat dry asphalt road at about 25km / h, with no obstacle within 50m ahead. The driver lightly presses the brake pedal, the pedal travel is about 6%, and the pedal pressing angular velocity is about 0.05rad / s.

[0155] Safety condition pre-judgment: data from each sensor — longitudinal deceleration a t ≈1.2m / s² (<M=1.5m / s²); (Jerk)J t ≈0.7m / s³ (<N=1.5m / s³); after attitude decoupling, the road slope θ road ≈0.4° (between θ min =-1.5° and θ max=1.5°); pedal travel 6% (< threshold 7%), pedal angular velocity 0.05 rad / s (< ω T =0.1rad / s); the distance to the obstacle ahead is greater than the safety threshold; ABS / ESP is not activated. The system determines that the intention is a non-emergency, smooth parking maneuver, and the safety conditions are met.

[0156] End-of-braking recognition: The system continuously monitors vehicle speed, and when v t Decay to v T = below 4km / h (i.e., v) t <v T When the deceleration changes smoothly and the pedal is in a light-pressed state, it is determined that the braking end stage has begun.

[0157] Clutch unloading execution (multi-unit coordination): ① Upon receiving the clutch unloading command, the TCU gradually disengages the clutch or releases the torque converter lock-up within approximately 200ms at a preset slope, eliminating the transmission of engine drag torque to the drivetrain; ② The ECU synchronously coordinates and controls the engine counter-drag torque, ensuring a smooth decay of the counter-drag torque and avoiding abrupt changes; ③ Based on the clutch disengagement state and the estimated counter-drag torque, the BCM / ESC performs feedforward compensation on the hydraulic braking force at the moment of clutch disengagement, briefly increasing the braking pressure by approximately 0.2–0.3 MPa to compensate for the decrease in total braking force caused by the disappearance of the counter-drag torque, maintaining continuous deceleration; ④ When the deceleration returns to a stable state and the vehicle speed approaches 0, the BCM gradually releases the hydraulic braking pressure at a set slope (approximately 0.1–0.15 MPa / s), allowing the vehicle to coast to 0 km / h with a near-constant, small deceleration.

[0158] Performance Comparison: Without this control, the instantaneous jet speed at the end of the braking condition can reach 3-5 m / s³ due to the sudden change in the friction coefficient from dynamic friction to static friction and the superposition of engine drag force, resulting in a noticeable "nodding" impact for the occupants. After introducing this control, the maximum jet speed at the end drops to below 1 m / s³, and the vehicle comes to a smooth stop. After stopping, the vehicle speed remains stable at 0 km / h, the system exits active control, and stores the braking data (intervention speed, deceleration curve, pedal characteristics, etc.) for parameter self-learning.

[0159] Example 3: Attitude decoupling and system non-intervention determination under slope conditions.

[0160] Static calibration: When the vehicle is stationary on a level road, the pitch angles of N=200 IMU points are collected and averaged to obtain the comprehensive offset angle θ0=+0.3°, i.e., θ0=(1 / N)·Σθ IMU (i). This offset angle covers both IMU installation error and vehicle static attitude deviation.

[0161] Scenario and Decoupled Calculation: The vehicle brakes at low speed on a longitudinal slope of approximately -3% (downhill). At a certain moment, the IMU measures θ.IMU =-2.3°. The change in front height h is measured by the front and rear suspension height sensors. f -h f0 =-12mm (front drop, braking pitch), rear height change h r -h r0 =+6mm, wheelbase L=2700mm, then the vehicle's dynamic pitch angle is:

[0162] =arctan[(-12-6) / 2700]≈-0.38°.

[0163] The actual road slope after decoupling: θ road =θ IMU -θ0-θ body =-2.3-(+0.3)-(-0.38)≈-2.22°. Since θ road <θ min (-1.5°) The system determines that it is a downhill condition and does not intervene in the clutch unloading control. The driver should brake to 0 km / h to avoid the risk of "rolling" on the slope after the clutch is disengaged.

[0164] Comparison Notes: Without attitude decoupling, the θ generated by braking pitching... body (In this example, approximately -0.38°) will be misclassified as part of the slope, causing θ to be... IMU -θ0≈-2.6°, thus exaggerating the slope estimate and affecting the accuracy of the judgment; this embodiment shows that the true slope can be restored after decoupling, which significantly improves the reliability of the judgment under the slope condition.

[0165] Example 4: Emergency braking and real-time safety reversal in case of abnormalities during the process.

[0166] Scenario A (Emergency Braking Without Intervention): The driver applies the brakes suddenly, the pedal travel reaches 25% (exceeding the upper limit of the threshold), and the pedal depressing angular velocity is 0.6 rad / s (>ω). T =0.1rad / s), longitudinal deceleration reaches 6m / s². 2 (>M), and Jerk exceeds the threshold, ABS is triggered. The system's safety condition prediction logic (highest priority, independent of the main logic) immediately determines it as emergency braking, without intervening in the clutch unloading control throughout the process, to ensure that the vehicle brakes with the shortest distance and time.

[0167] Scenario B (Real-time Reversal During Intervention): The system has entered the clutch unloading phase. If any of the following anomalies is detected during this process, the unloading will be terminated and normal braking and transmission logic will be restored within a very short time (limited by the CAN cycle, usually on the order of milliseconds): Abnormal increase in vehicle speed (such as when downhill inertia causes v) tWhen reversing, if the vehicle speed increases from 3 km / h, the driver re-applies the brake or accelerator pedal, or the distance to the obstacle ahead decreases to below the safe threshold 'a' (e.g., from 30m to 8m), ABS / ESP intervenes. During reversing, the BCM automatically increases braking force based on the vehicle speed recovery trend, always prioritizing vehicle safety.

[0168] Example 5: Adaptive learning process for key thresholds.

[0169] Self-learning mechanism: For each successful smooth parking, the control decision module extracts the feature quantities of that braking action (pre-intervention deceleration, Jerk, intervention speed, parking smoothness, etc.) and uses exponentially weighted moving average (EWMA) to update the threshold online.

[0170] X new =(1-α)·X old +α·X obs ,

[0171] Where X represents the threshold to be updated (e.g., M, N, v). T ω T θ max θ min ), X obs The safety characteristic value observed in this braking test is used. The forgetting factor α is set to 0.05 to 0.1, so that the threshold gradually conforms to the driver's habits while ensuring convergence stability.

[0172] Example: Referring to Table 1, for drivers accustomed to "gentle and early release," the system will trigger the vehicle speed threshold v after approximately 30 braking maneuvers. T The initial speed was adaptively adjusted from 4 km / h to approximately 3.3 km / h, delaying the intervention time to align with its late unloading behavior. For vehicles with excessive braking force, the acceleration threshold M was increased from 1.5 m / s² to approximately 1.9 m / s² to avoid frequent misjudgments of sudden brushing without intervention. max The convergence was achieved using the adjustment criterion that "the vehicle speed can continue to decrease in a short period of time after unloading without slipping"; due to differences in tire adhesion, load, wind resistance, etc., θ max With θ min The final convergence value is usually not perfectly symmetric.

[0173] Table 1: Example of adaptive learning for key thresholds (an individual driver)

[0174]

[0175] The above embodiments demonstrate that the present invention can be implemented without changing the original vehicle power system hardware structure, using only existing sensors and the vehicle CAN communication network. It significantly reduces braking jerking and improves ride comfort while prioritizing safety, and can adaptively optimize according to driving habits, demonstrating good engineering feasibility and application value.

[0176] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A braking jerking prevention system for fuel-powered vehicles, characterized in that, It includes a vehicle posture detection module, a vehicle posture decoupling module, a pedal travel and acceleration detection module, a vehicle speed monitoring module, a forward obstacle detection module, a control decision module, and a communication and execution module. The modules interact with each other via a CAN bus and send their respective data to the control decision module. After calculation, the control decision module sends the control commands to the communication and execution module via the CAN bus. Vehicle attitude detection module: provides basic data on vehicle dynamics and body attitude, and provides dual safety constraints of acceleration and slope for the control decision module; Vehicle attitude decoupling module: used to obtain the comprehensive offset angle θ0 and the vehicle dynamic pitch angle θ body ; Pedal travel and acceleration detection module: used to detect brake pedal travel and pedal depress angular velocity; Vehicle speed monitoring module: used to acquire vehicle speed information in real time; Forward obstacle detection module: Obtains the distance to obstacles ahead using millimeter-wave radar or a camera. ; Control Decision Module: The core is the algorithm control logic unit, which integrates signals from various sensors, uses a weighted fusion algorithm to calculate the timing of system intervention, and outputs transmission control commands and braking force adjustment signals; it has a self-learning function, dynamically adjusting parameters based on different users' driving history data to achieve personalized and smooth control; Control decision module and communication and execution module: Transmit decision signals to engine control unit and transmission control unit to realize clutch unloading control and braking force adjustment, delay control signals, and realize closed-loop control of the system.

2. The braking jerking prevention system for a fuel-powered vehicle according to claim 1, characterized in that, The vehicle posture detection module is responsible for detecting lateral acceleration. and the rate of change of acceleration With pitch angle If the lateral acceleration exceeds a threshold, indicating an emergency braking need from the driver, the system cannot intervene to ensure the vehicle brakes with the shortest distance and time. This is achieved through fusion calculations using accelerometer and gyroscope data. Let the lateral acceleration threshold be The system's judgment logic is as follows: This is used to determine the safe acceleration threshold. At that time, it was determined to be an emergency braking, and no coasting intervention was initiated; When the intervention conditions are met, prepare to execute clutch unloading control; in The self-learning threshold; After moving average filtering: ； Let the rate of change of lateral acceleration be The system's decision logic is as follows: This is used to determine the threshold for the rate of change of acceleration. At that time, it was determined to be an emergency braking, and no coasting intervention was initiated; When the intervention conditions are met, prepare to execute clutch unloading control; Where J is the self-learning threshold; After moving average filtering: ； The results are temporarily stored and used by the vehicle attitude decoupling module to calculate the actual road slope.

3. The braking jerking prevention system for a fuel-powered vehicle according to claim 1, characterized in that, The method for obtaining the comprehensive offset angle θ0 is as follows: when the vehicle is stationary on a level road surface or a road surface with a known slope, the pitch angle of the vehicle attitude detection module is collected over a period of time. IMU And calculate the average value, and then calculate θ0 based on the known road inclination angle; When a vehicle is stationary on a level road surface, the road's angle of inclination is zero. Therefore: ； Where N: the number of pitch angle data collected by the vehicle attitude detection module during the static calibration process; θ IMU (i): Pitch angle of the vehicle attitude detection module at the i-th sampling time; θ0: Comprehensive offset angle formed by IMU installation error, installation reference error and vehicle static attitude deviation; When the vehicle is stationary at a known slope angle θ k When the road surface is..., then: 。 4. The braking jerking prevention system for a fuel-powered vehicle according to claim 1, characterized in that, The vehicle dynamic pitch angle θ body The calculation method is as follows: when the vehicle is equipped with front and rear suspension height sensors or vehicle height sensors, the dynamic pitch angle of the vehicle body is directly calculated from the change in front and rear vehicle height. ； Where: θ body h is the vehicle's dynamic pitch angle. f h represents the current front axle position height. r h represents the current rear axle position height. f0 h represents the front axle position height under static reference conditions of the vehicle. r0 The rear axle height is the vehicle's position height under static reference conditions; L is the vehicle's wheelbase, or the longitudinal distance between the front and rear height measurement reference points; h f h f0 h represents the change in height of the front body relative to a static reference. r h r0 This refers to the change in height of the rear vehicle body relative to a static reference. The final road inclination angle is: ； Obtained by the above method road The system's overall judgment logic is used to determine the vehicle's slope status: When going uphill, the system does not intervene, and the driver's own operation is used to brake the vehicle to 0 km / h; When going downhill, the system does not intervene, and the driver's own operation is used to brake the vehicle to 0 km / h; Only when When the system intervenes, the clutch performs unloading control, completing one smooth control cycle; and The initial value of the system is taken as 1°~2°; The system adjusts through learning algorithms : The adjustment target is to ensure that the speed decreases in a short time, so as to avoid the "rolling" phenomenon after the clutch is unloaded.

5. A braking jerking prevention system for a fuel-powered vehicle according to claim 1, characterized in that, The brake pedal travel and the pedal depression angular velocity are detected by a displacement sensor installed on the brake pedal; when the pedal travel is greater than N%, the pedal depression angular velocity is greater than , the system determines that it is an emergency or forced braking. With ensuring safety as the primary objective, the vehicle is braked quickly to a standstill, and clutch unloading control does not intervene; when the travel is less than N%, the pedal depression speed is less than , the system intervenes to implement the clutch unloading control strategy; N is 5%-8%, is 0.1rad / s, and the pedal travel and acceleration detection module is used to determine whether it is an emergency braking situation.

6. The braking jerking prevention system for a fuel-powered vehicle according to claim 1, characterized in that, A Hall sensor is used to acquire vehicle speed information in real time; when the speed exceeds a set threshold... At that time, to ensure safety, the vehicle remains in the braking phase, maintaining braking force; When the speed is less than the set threshold At this time, the system intervenes in clutch unloading control: Normal braking; The system intervenes in the clutch unloading control logic; in The initial value is set to 3-5 km / h and is adaptively adjusted based on driving history. For stability assessment, the vehicle speed data uses a first-order low-pass filter. The system maintains smooth gliding during the steady phase and automatically increases braking force when a significant increase in speed is detected.

7. The braking jerking prevention system for a fuel-powered vehicle according to claim 1, characterized in that, When the distance is less than the safety threshold When the distance is greater than 100 km, maintain braking; when the distance is greater than 100 km, maintain braking. At this time, the system clutch unloads control.

8. A braking jerking prevention system for a fuel-powered vehicle according to claim 1, characterized in that, The execution flow of the control decision module and the communication and execution module is as follows: The engine control unit receives a clutch unloading control command and controls the clutch to gradually disengage; The transmission control unit coordinates and controls the engine drag torque according to the target deceleration requirement to avoid sudden changes in engine drag torque; The body controller feeds forward the hydraulic braking force based on the clutch disengagement state and the estimated engine drag torque. It briefly maintains or appropriately increases the braking pressure at the moment of clutch disengagement to compensate for the decrease in total braking force caused by the disappearance of engine drag torque. When the vehicle deceleration returns to a stable state and the vehicle speed approaches 0, the body controller gradually releases the hydraulic braking pressure according to the set slope, so that the vehicle stops smoothly. If ABS intervention, hill start conditions, emergency braking, or increased driver braking intent are detected, the system immediately disengages clutch unloading control and restores normal braking control and transmission mode.

9. A method for controlling braking jerking in a fuel-powered vehicle, applied to a braking jerking prevention system for a fuel-powered vehicle as described in any one of claims 1-8, characterized in that, include: System initialization and status monitoring: After the vehicle is powered on and started, the system enters the initialization state. Each sensor module begins to collect the vehicle's attitude, speed, brake pedal travel and distance to obstacles in front in real time. During this stage, the system only monitors and caches data and does not output any control commands to ensure that the original vehicle control system operates completely according to the established logic. Safety condition prediction: When the system detects that the driver has pressed the brake pedal at any time, and the brake pedal travel and pedal depressing angular velocity exceed the corresponding threshold, or when ABS and ESP are activated, the system immediately starts the safety condition judgment logic. The system stops or does not intervene and resumes the normal braking and transmission logic. This mechanism is independent of the main logic and has the highest priority. First, determine the vehicle speed. If the speed is too high, the risk is the greatest. Use the threshold speed as the judgment indicator. Acceleration, rate of change of acceleration, road gradient 1. Check if the distance to the obstacle in front exceeds the set threshold. If the value of the corresponding module exceeds the corresponding threshold, it is determined to be a normal braking condition. Normally, the driver controls the braking by foot pedal and the system does not intervene. Braking end stage identification process: Under the premise that safety conditions are met, the system continuously monitors the vehicle speed change. When the vehicle speed is lower than the set threshold and the deceleration change is stable, and the brake pedal is in a light pressing or slow release state, the system determines that the vehicle has entered the braking end stage, and the driver's goal is to stop smoothly. Clutch unloading control execution: At the end of the braking phase, the system sends a clutch unloading control command to the transmission control unit to gradually separate the power transmission and eliminate the engine drag force. At the same time, the system gradually releases the braking pressure according to the vehicle speed decay curve, allowing the vehicle to coast smoothly with natural deceleration until it stops. Throughout the process, the system monitors the vehicle speed, acceleration and braking status in parallel. Real-time safety reversal and abnormal handling: During the braking process, if abnormal increase in vehicle speed, driver use of brake pedal or increased braking, or intervention of ABS or ESP system are detected, the system will immediately terminate clutch unloading control and restore the original braking and transmission logic. Parking completion and system reset: When the vehicle speed drops to 0km / h and remains stable, the system exits the active control state, completing a complete braking jerk control process. At the same time, the braking data is stored for subsequent parameter self-learning and optimization adjustment, providing a control strategy that is more in line with driving habits for subsequent braking processes.

10. A method for controlling braking jerking in a fuel-powered vehicle according to claim 9, characterized in that, The system follows three basic principles during operation: safety first, end-of-pipe intervention, and minimum control intervention. The system only intervenes when the vehicle is safe to operate, the driver's braking intention is clear, and the vehicle is in the end stage of low-speed braking. At any moment when the system intervenes, if the brake pedal or accelerator pedal is detected to be depressed, the clutch unloading control system stops intervening in a very short time.

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