Brake-by-wire calibration method, device and equipment

Abstract

The present invention relates to the field of vehicle control technology and discloses a brake-by-wire calibration method, device, and apparatus. The method comprises obtaining vehicle gross mass, brake pedal travel data, vehicle speed data, and brake pressure data; performing a difference calculation based on the vehicle speed data to obtain wheel speed difference; combining a brake distribution coefficient model with the gross vehicle mass, vehicle speed data, and wheel speed difference to perform a brake distribution calculation to obtain a brake distribution coefficient; performing a brake torque calculation based on the gross vehicle mass, brake pressure data, and brake distribution coefficient to obtain a brake torque compensation value; performing a brake force correction calculation based on the gross vehicle mass and brake pressure data to obtain a brake force correction value; and performing a PID closed-loop system control calculation based on the brake torque compensation value, the brake force correction value, and brake pedal travel data to obtain a motor torque output value. This method accurately calculates the braking force and output torque, thereby ensuring braking reliability and stability.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control technology, and in particular to a brake-by-wire calibration method, device and equipment. Background Art

[0002] Currently, vehicle braking technology has become a critical component of vehicle control technology to ensure vehicle safety. While traditional hydraulic braking systems are mature and reliable, they have limitations in response speed, braking force control accuracy, and energy recovery. Therefore, brake-by-wire systems have emerged. They control braking through electronic signals, replacing traditional mechanical connections, providing faster response times and more precise braking force control.

[0003] In one existing technology, a brake-by-wire system uses a motor to drive the calipers to achieve braking. A main controller uses the brake pedal travel signal and a pre-set base map to determine the target braking force for the left and right calipers. This system is better suited for active brake energy recovery because it can adjust the braking force provided by the motor based on the braking state to meet actual needs. However, during brake energy recovery, this brake-by-wire system can experience a deviation between the actual motor braking force and the target braking force. Furthermore, when the anti-lock braking system is activated, the braking force of the entire vehicle deviates from the target braking force due to the need to redistribute the braking force to each wheel. Higher brake temperatures reduce the brake friction coefficient, requiring a higher base braking force to achieve the final braking force.

[0004] In summary, the existing technology uses a fixed ratio and fixed offset value method for correction. This method cannot well meet the compensation requirements of each caliper under different brake pedal strokes and different road conditions, cannot ensure the precise control of the braking force, and thus cannot guarantee the reliability and stability of braking. Summary of the Invention

[0005] The present invention provides a brake-by-wire calibration method, device and equipment to solve the problems of low braking reliability and stability.

[0006] In a first aspect, in order to solve the above technical problems, the present invention provides a brake-by-wire calibration method, comprising:

[0007] Obtaining vehicle gross mass, brake pedal travel data, vehicle speed data, and brake pressure data;

[0008] Performing a difference calculation based on the vehicle speed data to obtain a wheel speed difference;

[0009] In combination with a brake distribution coefficient model, a brake distribution calculation is performed according to the total vehicle mass, the vehicle speed data and the wheel speed difference to obtain a brake distribution coefficient;

[0010] Calculating the braking torque according to the vehicle's total mass, the braking pressure data, and the braking distribution coefficient to obtain a braking torque compensation value;

[0011] performing a braking force correction calculation based on the vehicle gross mass and the brake pressure data to obtain a braking force correction value;

[0012] A PID closed-loop system control calculation is performed according to the braking torque compensation value, the braking force correction value and the brake pedal stroke data to obtain a motor torque output value.

[0013] In an optional implementation, obtaining the vehicle's total mass, brake pedal travel data, vehicle speed data, and brake pressure data includes:

[0014] Obtain brake pressure data through a pressure sensor;

[0015] Obtain brake pedal travel data through a brake pedal displacement sensor;

[0016] The vehicle speed data is obtained through the speed sensor.

[0017] In an optional implementation, performing difference calculation based on the vehicle speed data to obtain the wheel speed difference includes:

[0018] The wheel speed difference is calculated using the following formula:

[0019] Δv FL =v FR -v FL

[0020] Δv RL =v RR -v RL

[0021] Among them, v FL is the speed of the left front wheel, v FR is the speed of the right front wheel, v RR is the speed of the right rear wheel, v RL is the speed of the left rear wheel, Δv FL is the front wheel speed difference, Δv RL It is the rear wheel speed difference.

[0022] In an optional embodiment, the braking distribution coefficient model is combined to perform braking distribution calculation according to the total vehicle mass, the vehicle speed data and the wheel speed difference to obtain the braking distribution coefficient, including:

[0023] The brake distribution coefficient is calculated using the following brake distribution coefficient model:

[0024]

[0025] Among them, F front represents the braking distribution coefficient, k is the adaptive factor, v is the vehicle speed, Δv FL is the front wheel speed difference, Δv RL It is the rear wheel speed difference.

[0026] In an optional embodiment, the calculating the braking torque based on the total vehicle mass, the braking pressure data, and the braking distribution coefficient to obtain the braking torque compensation value includes:

[0027] The braking force is calculated by multiplying the braking pressure data by a linear coefficient, wherein the linear coefficient is a preset constant;

[0028] Calculating a total braking torque based on the braking force and the total mass of the vehicle;

[0029] Calculating a braking torque compensation value according to the total braking torque and the braking distribution coefficient;

[0030] The calculation formula of the braking torque compensation value is as follows:

[0031] T motor =T req ·F front +T req ·F rear

[0032]

[0033] Where, T motor is the braking torque compensation value, F front is the front axle brake distribution coefficient, F rear is the rear axle brake distribution coefficient, T req represents the total braking torque, m represents the total mass of the vehicle, g is the acceleration due to gravity, F μ (t) is the braking force and L is the wheelbase length.

[0034] In an optional implementation, performing a braking force correction calculation based on the vehicle gross mass and the brake pressure data to obtain a braking force correction value includes:

[0035] Calculating a road adhesion coefficient based on the brake pressure data and a preset coefficient;

[0036] Calculating a vehicle deceleration based on the vehicle's total mass, the road adhesion coefficient, and the brake pressure data;

[0037] performing a braking force error calculation based on the vehicle deceleration and the brake pressure data to obtain a braking force difference;

[0038] Calculating a braking force correction value based on the braking force difference and the braking pressure data to obtain a braking force correction value;

[0039] The calculation formulas for the road adhesion coefficient, vehicle deceleration, braking force difference, and braking force correction value are as follows:

[0040] μ=a1P+a2

[0041]

[0042] F μ =q·P+ΔF μ

[0043] Where μ is the road adhesion coefficient, a1 is the first preset coefficient, a2 is the second preset coefficient, P is the braking pressure; a is the vehicle deceleration, q is the control coefficient, m is the total vehicle mass, g is the acceleration of gravity; ΔF μ is the braking force difference, k1 is the first preset coefficient, k2 is the second preset coefficient, and v is the vehicle speed; F μ is the braking force correction value.

[0044] In an optional embodiment, performing a PID closed-loop system control calculation based on the braking torque compensation value, the braking force correction value, and the brake pedal travel data to obtain a motor torque output value includes:

[0045] According to the brake pedal stroke data, multiplying it by a constant coefficient to obtain the actual braking force;

[0046] Subtracting the actual braking force from the braking force correction value to obtain a braking error value;

[0047] According to the braking error value and the braking torque compensation value, a PID closed-loop control calculation is performed to obtain the motor torque output value. The calculation formula of the motor torque output value is as follows:

[0048]

[0049] Among them, T motor,adjusted Indicates the motor torque output value, T motor is the braking torque compensation value, e r is the braking error value, K p is the proportional gain coefficient, K i is the integral gain coefficient, K d is the differential gain coefficient.

[0050] In a second aspect, the present invention provides a brake-by-wire calibration device, comprising:

[0051] A data acquisition module is used to acquire vehicle gross mass, brake pedal travel data, vehicle speed data, and brake pressure data;

[0052] A wheel speed difference calculation module, configured to calculate the difference based on the vehicle speed data to obtain the wheel speed difference;

[0053] a distribution coefficient calculation module, configured to perform a brake distribution calculation based on the vehicle's gross mass, the vehicle speed data, and the wheel speed difference in combination with a brake distribution coefficient model to obtain a brake distribution coefficient;

[0054] a braking torque calculation module, configured to calculate the braking torque according to the total vehicle mass, the braking pressure data, and the braking distribution coefficient to obtain a braking torque compensation value;

[0055] a braking force calculation module, configured to perform a braking force correction calculation based on the vehicle's gross mass and the braking pressure data to obtain a braking force correction value;

[0056] The torque output module is used to perform PID closed-loop system control calculation according to the braking torque compensation value, the braking force correction value and the brake pedal stroke data to obtain a motor torque output value.

[0057] In a third aspect, the present invention further provides an electronic device comprising a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor implements any one of the above-mentioned methods for calibrating wire control braking when executing the computer program.

[0058] In a fourth aspect, the present invention further provides a computer-readable storage medium, which includes a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute any one of the above-mentioned wire control braking calibration methods.

[0059] Compared with the prior art, the present invention has the following beneficial effects: the present method discloses a calibration method for wire-controlled braking, comprising obtaining the total vehicle mass, brake pedal travel data, vehicle speed data and brake pressure data; performing a difference calculation based on the vehicle speed data to obtain a wheel speed difference; combining a brake distribution coefficient model, performing a brake distribution calculation based on the total vehicle mass, the vehicle speed data and the wheel speed difference to obtain a brake distribution coefficient; performing a brake torque calculation based on the total vehicle mass, the brake pressure data and the brake distribution coefficient to obtain a brake torque compensation value; performing a brake force correction calculation based on the total vehicle mass and the brake pressure data to obtain a brake force correction value; performing a PID closed-loop system control calculation based on the brake torque compensation value, the brake force correction value and the brake pedal travel data to obtain a motor torque output value.

[0060] The present invention combines the driver's braking intention, i.e., pedal stroke, with precise dynamic factors such as vehicle speed, wheel speed difference, road adhesion coefficient, and brake pressure, so that the system can accurately calculate the required braking force at every moment. In addition, the PID closed-loop control system is adopted to eliminate errors and smoothly adjust the motor torque output, thereby ensuring the accuracy, response speed and stability of vehicle braking. The brake pedal stroke, vehicle speed, wheel speed and other data are acquired in real time through sensors to ensure the accuracy of input data. Utilizing PID control and brake correction mechanisms, the motor output torque can be adjusted in real time to ensure that the braking system can respond quickly and accurately under various working conditions. By comprehensively considering factors such as road adhesion, total vehicle mass, brake pressure, and wheel speed difference, it can handle different driving environments and road conditions and ensure the robustness of the system. By distributing the braking force to the front and rear wheels and adjusting the braking parameters according to actual conditions, it is ensured that even in extreme cases, some wheels will not be over-braked or slipped, thereby ensuring the braking stability and safety of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 is a schematic diagram of a brake-by-wire calibration process provided by the first embodiment of the present method;

[0062] Figure 2 2 is a diagram of a brake-by-wire calibration device provided in the second embodiment of the present method. DETAILED DESCRIPTION

[0063] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0064] Reference Figure 1 A first embodiment of the present invention provides a brake-by-wire calibration method, comprising the following steps:

[0065] S11, acquiring vehicle gross mass, brake pedal travel data, vehicle speed data, and brake pressure data;

[0066] S12, performing difference calculation based on the vehicle speed data to obtain a wheel speed difference;

[0067] S13, combining a braking distribution coefficient model, performing a braking distribution calculation based on the vehicle's gross mass, the vehicle speed data, and the wheel speed difference to obtain a braking distribution coefficient;

[0068] S14, calculating the braking torque according to the total vehicle mass, the braking pressure data, and the braking distribution coefficient to obtain a braking torque compensation value;

[0069] S15, performing a braking force correction calculation based on the vehicle gross mass and the brake pressure data to obtain a braking force correction value;

[0070] S16 , performing PID closed-loop system control calculation according to the braking torque compensation value, the braking force correction value, and the brake pedal stroke data to obtain a motor torque output value.

[0071] In step S11, it is necessary to obtain the vehicle's total mass, brake pedal travel data, vehicle speed data, and brake pressure data, including:

[0072] The brake pressure data is obtained through the pressure sensor; the brake pedal travel data is obtained through the brake pedal displacement sensor; and the vehicle speed data is obtained through the speed sensor.

[0073] It should be noted that gross vehicle mass refers to the weight of the vehicle, including the combined weight of all components, including the body, engine, fuel, passengers, and cargo. The vehicle's gross mass is a key parameter for calculating braking system performance and can be measured using a vehicle electronic weighing system or pressure sensor. Brake pedal travel refers to the distance the pedal moves from the moment the driver depresses the brake pedal to the moment the braking system begins to operate. It reflects the responsiveness of the braking system; excessive travel indicates a problem with the braking system. Brake pedal travel data is acquired using a brake pedal displacement sensor. Brake pressure data refers to the pressure applied to the brakes by the hydraulic or pneumatic pressure within the braking system. It is an important indicator of the braking system's strength and response speed. Higher brake pressure indicates greater braking force.

[0074] In step S12, a difference calculation is performed based on the vehicle speed data to obtain a wheel speed difference.

[0075] In one implementation, the wheel speed difference can be calculated using the following formula:

[0076] Δv FL =v FR -v FL

[0077] Δv RL =v RR -v RL

[0078] Among them, v FL is the speed of the left front wheel, v FR is the speed of the right front wheel, v RR is the speed of the right rear wheel, v RL is the speed of the left rear wheel, ΔvFL is the front wheel speed difference, Δv RL It is the rear wheel speed difference.

[0079] It should be noted that v FL is the speed of the left front wheel, v FR is the speed of the right front wheel, v RR is the speed of the right rear wheel, v RL The speed of the left rear wheel can be obtained using a wheel speed sensor installed on the left front wheel, such as a magnetic encoder or optical encoder. The vehicle's handling and stability depend on the coordination of all four wheels. If the wheel speed difference between the wheels is greater than 3 meters per second, it means that the vehicle has uneven traction or slip. When the wheel speed difference between the left and right rear wheels is greater than 2 meters per second, it can be judged that there is a problem such as sideslip or power imbalance. The rear wheel speed is used to monitor the traction distribution and stability of the rear axle, which is very critical for autonomous driving or stability control systems.

[0080] Wheel speed differential reflects the difference in traction between wheels and is crucial for preventing slip and loss of traction. This traction differential allows the control system to automatically adjust the braking system to ensure vehicle stability. As a key indicator of vehicle dynamic behavior, wheel speed differential can reveal issues such as slippage and stalling during braking, providing early warning or intervention. By analyzing the speed differential between the front and rear wheels, the vehicle can more precisely distribute braking force, ensuring that each wheel functions properly and preventing loss of control, especially in complex driving environments such as slippery roads and emergency braking situations.

[0081] In step S13, a braking distribution coefficient model is combined with a braking distribution coefficient calculation to obtain a braking distribution coefficient according to the total vehicle mass, the vehicle speed data and the wheel speed difference.

[0082] In one implementation, the braking distribution coefficient is calculated using the following braking distribution coefficient model:

[0083]

[0084] Among them, F front represents the braking distribution coefficient, k is the adaptive factor, v is the vehicle speed, Δv FL is the front wheel speed difference, Δv RL It is the rear wheel speed difference.

[0085] It should be noted that F front Indicates the brake distribution coefficient, that is, the proportion of the braking force borne by the front axle to the total braking force. It determines how the braking force is distributed between the front and rear wheels during braking. front It is calculated by the formula based on the front wheel speed difference Δv FL, rear wheel speed difference Δv RL , adaptive factor k and vehicle speed v for dynamic calculation. The calculated F front It will be used to adjust the braking force distribution in the braking system. front , can achieve the optimal distribution of braking force on the front and rear axles, ensuring the braking performance of the vehicle under different working conditions. By precisely adjusting the front axle braking distribution coefficient F front , can effectively balance the traction of the front and rear wheels, and avoid loss of control or uneven braking due to overload or underload of the front or rear axle. For autonomous driving and intelligent braking systems, reasonable F front It is an important factor in improving braking stability, safety, and comfort. This factor mainly reflects the nonlinear effect of speed on braking distribution. At high speeds, the front wheels bear more braking force.

[0086] k is an adaptive factor used to adjust the influence of vehicle speed on brake distribution in the brake distribution coefficient model. It is a preset constant. In the vehicle control system, the adaptive factor can be dynamically adjusted according to different driving environments and road conditions. The value of k is preset based on the vehicle design, experimental data, and the specific characteristics of the braking system. In a dynamic system, k can be adjusted based on real-time feedback, such as wheel speed and brake pressure. The function of k is to adjust the braking force distribution between the front and rear wheels according to the vehicle speed. At higher vehicle speeds, the front wheels need to bear a greater braking load to ensure stability. By adjusting k, the system can be more adaptable to different driving environments and road conditions.

[0087] v is the vehicle's current speed. It reflects the vehicle's state of motion and directly affects how the vehicle's braking system distributes braking force. The faster the vehicle, the longer the required braking distance, so the braking distribution will also be adjusted. The vehicle's speed can be obtained through the vehicle's speed sensors, such as the GPS speedometer and vehicle speed sensor. The vehicle's speed is used as one of the input parameters to influence the calculation of the brake distribution coefficient model. In the brake distribution formula, speed works together with the adaptive factor to adjust the braking force distribution between the front and rear wheels. Vehicle speed is an important factor affecting brake distribution. At high speeds, to avoid braking imbalance, the system will distribute more braking force to the front axle. At low speeds, the system will adjust to a more even braking distribution to improve comfort and control accuracy.

[0088] This model determines the brake distribution coefficient based on the wheel speed difference between the front and rear wheels. The ratio between the front and rear wheel speed differences indicates the difference in stability between the front and rear axles of the vehicle. When the front wheel speed difference is greater than the rear wheel speed difference, the front axle bears more braking force. The model adjusts brake distribution based on vehicle speed. As vehicle speed increases, the braking burden on the front wheels increases, ensuring vehicle stability and control at high speeds. This model dynamically adjusts brake distribution based on the vehicle's current driving state, ensuring optimal braking system performance under various driving conditions.

[0089] In step S14 , a braking torque is calculated based on the total vehicle mass, the braking pressure data, and the braking distribution coefficient to obtain a braking torque compensation value.

[0090] In one implementation, a total braking torque is calculated based on the braking force and the total mass of the vehicle;

[0091] Calculating a braking torque compensation value according to the total braking torque and the braking distribution coefficient;

[0092] The calculation formula of the braking torque compensation value is as follows:

[0093] T motor =T req ·F front +T req ·F rear

[0094]

[0095] Where, T motor is the braking torque compensation value, F front is the front axle brake distribution coefficient, F rear is the rear axle brake distribution coefficient, T req represents the total braking torque, m represents the total mass of the vehicle, g is the acceleration due to gravity, F μ (t) is the braking force and L is the wheelbase length.

[0096] It should be noted that T motor Braking torque compensation is the amount of braking torque the motor needs to output. It is adjusted based on the vehicle's total braking demand and the braking distribution between the front and rear axles to ensure the correct braking force is applied to each wheel. Braking torque compensation is used to adjust the motor's braking force output to ensure proper torque distribution during braking. Braking torque compensation is crucial for smooth and even vehicle deceleration. It ensures that braking force distribution between the front and rear axles meets the vehicle's dynamic requirements, preventing loss of control or vehicle yaw, especially during emergency braking and complex road conditions.

[0097] Frear The rear axle brake distribution coefficient indicates the proportion of braking force to be distributed to the rear axle. The rear axle brake distribution coefficient reflects the rear axle braking demand and is dynamically adjusted based on the vehicle's motion. The rear axle brake distribution coefficient is combined with the total brake torque to calculate the rear axle braking torque and ultimately adjust the motor's braking output. The rear axle brake distribution coefficient helps maintain vehicle stability, especially during sudden braking or skidding situations. Excessive rear axle braking force can cause the rear wheels to lock, while insufficient braking force can result in insufficient vehicle deceleration, compromising safety.

[0098] T req Indicates the total braking torque, which represents the braking requirement of the vehicle in the current driving state. It is determined by factors such as the total mass of the vehicle, braking force, and road adhesion. req This is used to calculate the actual braking torque for each axle, ultimately adjusting the motor's output torque. Total braking torque is the basis for determining the vehicle's overall braking demand. It reflects the vehicle's current deceleration requirements and directly influences the design and control of the braking system. Accurately calculating total braking torque ensures that the braking system can provide sufficient braking force to safely stop the vehicle under all circumstances.

[0099] m is the vehicle's gross mass, which refers to the combined weight of the vehicle and all its loads. This value is provided by the vehicle manufacturer and can also be obtained using a weighing device. Mass is used to calculate the total braking torque, which affects the vehicle's deceleration ability. Greater mass requires greater braking force, making mass a crucial factor in calculating braking torque. Vehicle mass directly impacts braking system design, as heavier vehicles require more braking torque to achieve the same deceleration. Therefore, accurately calculating the vehicle's gross mass is crucial to designing an effective braking system.

[0100] g is the acceleration due to gravity of the Earth, which is 9.81 m / s 2 It is used to calculate the braking torque required by the vehicle. Gravity converts mass into a corresponding gravitational force, as the braking force depends on the vehicle's mass interacting with gravity. It helps ensure that the calculated braking torque matches the actual physical requirements.

[0101] F μ (t) is the braking force, specifically the friction between the vehicle and the road. Ground adhesion is measured using a brake pressure sensor or slip sensor, or estimated based on road conditions. Friction is related to tire adhesion and directly affects braking effectiveness. Friction is the fundamental factor in determining braking efficiency, with higher friction providing greater braking performance. The control system must account for the impact of varying road adhesion on the vehicle's braking force to optimize the braking system's response.

[0102] L is the wheelbase length, which is the distance between the front and rear axles of the vehicle. The wheelbase length is a fixed parameter of the vehicle and can be obtained from the vehicle manual or actual measurement. It is used to calculate the total braking torque, which reflects the torque distribution between the front and rear axles when the vehicle brakes. The length of the wheelbase affects the stability of the vehicle during braking. A longer wheelbase can provide more stable braking performance, while a shorter wheelbase results in a faster response but is more prone to instability. These parameters work together through a formula to accurately calculate the braking requirements of the vehicle under different operating conditions. By calculating the total braking torque and the braking distribution coefficient of the front and rear axles, the braking system can dynamically adjust the braking force of each wheel, thereby achieving more efficient and safer braking effects.

[0103] In step S15 , a braking force correction calculation is performed based on the vehicle gross mass and the brake pressure data to obtain a braking force correction value.

[0104] In one implementation, a road adhesion coefficient is calculated based on the brake pressure data and a preset coefficient;

[0105] Calculating a vehicle deceleration based on the vehicle's total mass, the road adhesion coefficient, and the brake pressure data;

[0106] performing a braking force error calculation based on the vehicle deceleration and the brake pressure data to obtain a braking force difference;

[0107] Calculating a braking force correction value based on the braking force difference and the braking pressure data to obtain a braking force correction value;

[0108] The calculation formulas for the road adhesion coefficient, vehicle deceleration, braking force difference, and braking force correction value are as follows:

[0109] μ=a1P+a2

[0110]

[0111] F μ =q·P+ΔF μ

[0112] Where μ is the road adhesion coefficient, a1 is the first preset coefficient, a2 is the second preset coefficient, P is the braking pressure; a is the vehicle deceleration, q is the control coefficient, m is the total vehicle mass, g is the acceleration of gravity; ΔF μ is the braking force difference, k1 is the first preset coefficient, k2 is the second preset coefficient, and v is the vehicle speed; F μ is the braking force correction value.

[0113] It should be noted that μ is the coefficient of friction between the vehicle's tires and the road surface, indicating the adhesion between the tires and the ground. It is a key factor influencing braking performance, as greater friction results in stronger braking. The road adhesion coefficient is calculated using brake pressure data and a preset coefficient. As a quantitative representation of road adhesion, μ directly affects braking effectiveness. It is used along with vehicle deceleration and other parameters to further calculate vehicle braking performance and corrections. The road adhesion coefficient significantly impacts vehicle braking. A high adhesion coefficient means stronger braking, while a low adhesion coefficient leads to inefficient braking and even loss of vehicle control. Therefore, real-time calculation of the road adhesion coefficient is crucial to ensuring braking safety.

[0114] a is the vehicle's deceleration during braking, determined by the vehicle's gross mass, brake pressure, road adhesion, and other dynamic factors. The degree of vehicle deceleration influences subsequent braking force calculations. It can be used in conjunction with other parameters, such as brake pressure and speed, to calculate brake force corrections to further optimize braking effectiveness. Vehicle deceleration is a key factor influencing braking efficiency and stability. The greater the deceleration, the greater the vehicle's speed reduction per unit time, while the reverse is true, requiring more time to stop. Therefore, accurately calculating vehicle deceleration is crucial for optimizing braking performance.

[0115] ΔF μ Braking force differential represents the deviation between actual braking force and the ideal braking force during braking. This value is used to further calculate the braking force correction value. It helps adjust the braking system's response to correct for braking errors caused by various factors, such as road adhesion variations and sensor errors. Braking force differential measures the difference between actual braking force and target braking force. By optimizing this value, the system can more precisely adjust braking output, thereby improving braking performance and driving safety.

[0116] F μ Is the braking force correction value. The corrected braking force represents the actual braking force applied to the vehicle after taking into account the braking force difference. It is through compensation and correction of the braking force to ensure that the vehicle has appropriate braking performance under different driving conditions. μ This corrected braking force directly impacts the vehicle's deceleration process and ensures a stable braking response under varying road conditions. It is used to adjust control commands to the motor or actuator to optimize braking effectiveness. By calculating the corrected braking force, the system dynamically adjusts the braking system's response to compensate for inconsistent braking force caused by factors such as road adhesion variations and sensor errors. The ultimate goal is to ensure smooth and stable braking under all conditions.

[0117] This model comprehensively considers factors such as friction coefficient and deceleration to help adjust braking system performance in real time, ensuring smooth and efficient braking under various driving conditions. By calculating road adhesion coefficient, deceleration, braking force differential, and correction values, the system dynamically responds to different road surfaces and environmental changes, optimizing braking performance and ensuring driving safety.

[0118] In step S16 , a PID closed-loop system control calculation is performed based on the braking torque compensation value, the braking force correction value, and the brake pedal stroke data to obtain a motor torque output value.

[0119] In one implementation, the actual braking force is obtained by multiplying the brake pedal travel data by a constant coefficient;

[0120] Subtracting the actual braking force from the braking force correction value to obtain a braking error value;

[0121] According to the braking error value and the braking torque compensation value, a PID closed-loop control calculation is performed to obtain the motor torque output value. The calculation formula of the motor torque output value is as follows:

[0122]

[0123] Among them, T motor,adjusted Indicates the motor torque output value, T motor is the braking torque compensation value, e r is the braking error value, K p is the proportional gain coefficient, K i is the integral gain coefficient, K d is the differential gain coefficient.

[0124] It's important to note that in this implementation, PID control is used to dynamically adjust the motor's torque output to precisely control the braking system's behavior. PID control is a feedback control mechanism that uses proportional, integral, and differential components to adjust the braking system by taking into account the current error, the accumulation of past errors, and the rate of change of the error.

[0125] Brake pedal travel data indicates the distance the driver depresses the brake pedal. This data is a direct indicator of the driver's intended braking force. This data is acquired using a displacement sensor mounted on the brake pedal. This sensor, a potentiometer or displacement sensor, detects pedal movement in real time. The brake pedal travel data is multiplied by a constant coefficient to determine the actual braking force. Brake pedal travel is a direct input to the braking operation, directly corresponding to the driver's intended driving intention. Therefore, accurate brake pedal travel data is crucial for precise braking system control.

[0126] The constant coefficient is a preset constant used to adjust the relationship between actual braking force and brake pedal travel. It can be derived from experimental data or empirical models and is used to convert pedal travel into braking force. This coefficient is determined during the design phase and can be adjusted based on vehicle type, braking system characteristics, and driver operating habits. The constant coefficient varies across different braking systems and serves to convert driver input into the braking force required by the control system. Its accuracy directly impacts the accuracy of the braking system's response.

[0127] Actual braking force refers to the braking force applied by the driver via the brake pedal. It is proportional to the brake pedal travel and a constant coefficient. The actual braking force is compared with the braking force correction value to calculate the braking error, which is used as an input in PID control to adjust the motor output. The actual braking force is the driver's control input, indicating the degree of vehicle deceleration desired by the driver. Accurately determining the actual braking force is fundamental to subsequent control steps.

[0128] The braking error is the difference between the actual braking force and the ideal braking force. It indicates the error in the current vehicle deceleration process. The braking error is one of the inputs to PID control. By feedback-regulating the error, the PID controller dynamically adjusts the motor torque output to eliminate the braking error. The braking error directly reflects the performance of the braking system. When the error is greater than 3, it means that the system is not correctly implementing the driver's intention, and PID control can be adjusted to reduce this error.

[0129] The brake torque compensation value is calculated by the control system to adjust the motor output torque to compensate for various dynamic errors in the system. The brake torque compensation value is calculated based on factors such as previous brake distribution and brake pressure. It represents the desired torque output. Combined with the adjustment results of the PID control output, the brake torque compensation value determines the final motor output torque and adjusts the vehicle's braking response. This value ensures precise control of the braking system, especially in dynamic environments, and effectively eliminates external factors that interfere with braking performance.

[0130] A PID controller is a feedback control mechanism that adjusts for errors through proportional, integral, and differential components to ensure the system output reaches the desired target. A PID controller requires three gain parameters: proportional gain, integral gain, and differential gain. These gain parameters are determined through experimentation or tuning. The goal of a PID controller is to minimize braking error by dynamically adjusting motor torque, ensuring that the vehicle's braking system responds accurately and smoothly to driver input. The proportional term addresses the current error, the integral term corrects the accumulated error, and the differential term offsets the changing error trend.

[0131] This control strategy comprehensively considers braking error, brake correction value, and motor torque compensation, combined with PID control to precisely adjust motor output, ensuring stable braking performance under different vehicle operating conditions. Specifically, by providing feedback on braking error, PID control optimizes motor torque output, enabling precise control of the braking process, thereby improving driving safety and smoothing braking response.

[0132] In summary, the present invention discloses a calibration method for wire-controlled braking, comprising obtaining vehicle gross mass, brake pedal travel data, vehicle speed data, and brake pressure data; performing a difference calculation based on the vehicle speed data to obtain a wheel speed difference; and by calculating the wheel speed difference between the front and rear wheels, the method can dynamically adjust the braking distribution between the wheels to ensure that each wheel can achieve the best braking effect. The wheel speed difference reflects the differential movement between the wheels. By accurately calculating the braking distribution coefficient, the system can flexibly distribute the braking force between the front and rear wheels according to the wheel speed difference and changes in vehicle speed. This dynamic braking distribution not only ensures a balanced braking performance, but also prevents over-braking or slipping of a wheel, thereby improving braking stability and safety.

[0133] A preset constant coefficient converts pedal travel into actual braking force, ensuring the driver's intention is correctly mapped to the vehicle's actual braking response. The constant coefficient can be adjusted to suit different vehicles and braking systems for even more precise control.

[0134] In conjunction with the brake distribution coefficient model, brake distribution is calculated based on the vehicle's gross mass, vehicle speed data, and wheel speed difference to obtain the brake distribution coefficient. Braking torque is calculated based on the vehicle's gross mass, brake pressure data, and the brake distribution coefficient to obtain a brake torque compensation value. Braking force correction is calculated based on the vehicle's gross mass and brake pressure data to obtain a brake force correction value. A PID closed-loop system control calculation is performed based on the brake torque compensation value, the brake force correction value, and brake pedal travel data to obtain the motor torque output value. This feedback mechanism continuously adjusts the motor torque, fine-tuning the brake system's response and eliminating errors caused by system delays, nonlinearities, or external factors such as changing road conditions.

[0135] The braking torque compensation value in this method is calculated based on multiple factors, such as braking pressure, braking distribution coefficient, road adhesion coefficient, etc. By considering multiple dynamic factors, the system can more accurately judge and adjust the required braking force. For example, factors such as vehicle deceleration, braking pressure and road adhesion coefficient will affect the braking effect, so the system can dynamically adjust the output according to the real-time situation at every moment. This method can effectively deal with unstable factors that may affect braking performance through real-time feedback mechanism PID control and multi-dimensional correction values. For example, on wet or icy roads, the adhesion coefficient will be significantly reduced. By calculating the road adhesion coefficient and performing braking corrections, the system can adjust the braking strategy to ensure safe and stable braking effects even under adverse driving conditions. This method combines precise dynamic adjustment, real-time feedback and comprehensive calculation of multiple factors to effectively ensure the accuracy, stability and reliability of the braking system.

[0136] Reference Figure 2 A second embodiment of the present invention provides a brake-by-wire calibration device, comprising:

[0137] A data acquisition module is used to acquire vehicle gross mass, brake pedal travel data, vehicle speed data, and brake pressure data;

[0138] A wheel speed difference calculation module, configured to calculate the difference based on the vehicle speed data to obtain the wheel speed difference;

[0139] a distribution coefficient calculation module, configured to perform a brake distribution calculation based on the vehicle's total mass, the vehicle speed data, and the wheel speed difference in combination with a brake distribution coefficient model to obtain a brake distribution coefficient;

[0140] a braking torque calculation module, configured to calculate the braking torque according to the total vehicle mass, the braking pressure data, and the braking distribution coefficient to obtain a braking torque compensation value;

[0141] a braking force calculation module, configured to perform a braking force correction calculation based on the vehicle's gross mass and the braking pressure data to obtain a braking force correction value;

[0142] The torque output module is used to perform PID closed-loop system control calculation according to the braking torque compensation value, the braking force correction value and the brake pedal stroke data to obtain a motor torque output value.

[0143] It should be noted that the brake-by-wire calibration device provided in an embodiment of the present invention is used to execute all the process steps of the brake-by-wire calibration method of the above embodiment. The working principles and beneficial effects of the two correspond one to one, and thus will not be described in detail.

[0144] An embodiment of the present invention further provides an electronic device. The electronic device includes: a processor, a memory, and a computer program stored in the memory and executable on the processor, such as a brake-by-wire calibration program. When the processor executes the computer program, the steps of the above-mentioned brake-by-wire calibration method embodiments are implemented, such as Figure 1 Alternatively, when the processor executes the computer program, the functions of the modules / units in the above-mentioned device embodiments are realized, such as the braking force calculation module.

[0145] Exemplarily, the computer program may be divided into one or more modules / units, which are stored in the memory and executed by the processor to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, and the instruction segments are used to describe the execution process of the computer program in the electronic device.

[0146] The electronic device may be a computing device such as a desktop computer, notebook, PDA, or smart tablet. The electronic device may include, but is not limited to, a processor and memory. Those skilled in the art will appreciate that the aforementioned components are merely examples of electronic devices and do not constitute a limitation of the electronic device. The electronic device may include more or fewer components than those described above, or a combination of certain components, or different components. For example, the electronic device may also include input / output devices, network access devices, buses, and the like.

[0147] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the electronic device, connecting various parts of the entire electronic device using various interfaces and lines.

[0148] The memory can be used to store the computer programs and / or modules, and the processor realizes various functions of the electronic device by running or executing the computer programs and / or modules stored in the memory and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required for a function (such as a sound playback function, an image playback function, etc.); the data storage area can store data created based on the use of the mobile phone (such as audio data, a phone book, etc.). In addition, the memory can include a high-speed random access memory and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage device.

[0149] Wherein, if the module / unit integrated in the electronic device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the process in the above-mentioned embodiment method, and can also be completed by a computer program to instruct the relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, it can implement the steps of each of the above-mentioned method embodiments. Wherein, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0150] It should be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed across multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment. In addition, in the drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art can understand and implement the present invention without inventive effort.

[0151] The specific embodiments described above further illustrate the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A brake-by-wire calibration method, characterized in that: Executed by a computer, including: Obtaining vehicle gross mass, brake pedal travel data, vehicle speed data, and brake pressure data; Performing a difference calculation based on the vehicle speed data to obtain a wheel speed difference; In combination with a brake distribution coefficient model, a brake distribution calculation is performed based on the total vehicle mass, the vehicle speed data, and the wheel speed difference to obtain a brake distribution coefficient; Calculating the braking torque according to the vehicle's total mass, the braking pressure data, and the braking distribution coefficient to obtain a braking torque compensation value; performing a braking force correction calculation based on the vehicle gross mass and the brake pressure data to obtain a braking force correction value; performing a PID closed-loop system control calculation according to the braking torque compensation value, the braking force correction value, and the brake pedal stroke data to obtain a motor torque output value; The step of performing a PID closed-loop system control calculation based on the braking torque compensation value, the braking force correction value, and the brake pedal stroke data to obtain a motor torque output value includes: According to the brake pedal travel data, the actual braking force is obtained by multiplying the brake pedal travel data by a constant coefficient; Subtracting the actual braking force from the braking force correction value to obtain a braking error value; According to the braking error value and the braking torque compensation value, a PID closed-loop control calculation is performed to obtain the motor torque output value. The calculation formula of the motor torque output value is as follows: in, Indicates the motor torque output value, is the braking torque compensation value, is the braking error value, is the proportional gain coefficient, is the integral gain coefficient, is the differential gain coefficient.

2. The brake-by-wire calibration method according to claim 1, characterized in that: The obtaining of the vehicle's gross mass, brake pedal travel data, vehicle speed data, and brake pressure data includes: Obtain brake pressure data through a pressure sensor; Obtain brake pedal travel data through a brake pedal displacement sensor; The vehicle speed data is obtained through the speed sensor.

3. The brake-by-wire calibration method according to claim 1, wherein: The step of performing difference calculation based on the vehicle speed data to obtain the wheel speed difference includes: The wheel speed difference is calculated using the following formula: in, is the speed of the left front wheel, is the speed of the right front wheel, is the speed of the right rear wheel, is the speed of the left rear wheel, is the front wheel speed difference, It is the rear wheel speed difference.

4. The brake-by-wire calibration method according to claim 1, wherein: The combined braking distribution coefficient model performs braking distribution calculation according to the vehicle gross mass, the vehicle speed data, and the wheel speed difference to obtain the braking distribution coefficient, including: The brake distribution coefficient is calculated using the following brake distribution coefficient model: in, represents the brake distribution coefficient, is the adaptive factor, is the vehicle speed, is the front wheel speed difference, It is the rear wheel speed difference.

5. The brake-by-wire calibration method according to claim 1, wherein: The performing a braking force correction calculation based on the vehicle gross mass and the brake pressure data to obtain a braking force correction value includes: Calculating a road adhesion coefficient based on the brake pressure data and a preset coefficient; Calculating a vehicle deceleration based on the vehicle's total mass, the road adhesion coefficient, and the brake pressure data; performing a braking force error calculation based on the vehicle deceleration and the brake pressure data to obtain a braking force difference; Calculating a braking force correction value based on the braking force difference and the braking pressure data to obtain a braking force correction value; The calculation formulas for the road adhesion coefficient, vehicle deceleration, braking force difference, and braking force correction value are as follows: Where, is the road adhesion coefficient, is the first preset coefficient, is the second preset coefficient, is the brake pressure; is the vehicle deceleration, is the control coefficient, is the gross vehicle mass, is the acceleration due to gravity; is the braking force difference, is the first preset coefficient, is the second preset coefficient, is the vehicle speed; is the braking force correction value.

6. A brake-by-wire calibration device, characterized in that: A brake-by-wire calibration method for implementing any one of claims 1 to 5, comprising: A data acquisition module is used to acquire vehicle gross mass, brake pedal travel data, vehicle speed data, and brake pressure data; A wheel speed difference calculation module, configured to calculate the difference based on the vehicle speed data to obtain the wheel speed difference; a distribution coefficient calculation module for performing a brake distribution calculation based on the vehicle's total mass, the vehicle speed data, and the wheel speed difference in combination with a brake distribution coefficient model to obtain a brake distribution coefficient; a braking torque calculation module, configured to calculate the braking torque according to the total vehicle mass, the braking pressure data, and the braking distribution coefficient to obtain a braking torque compensation value; a braking force calculation module, configured to perform a braking force correction calculation based on the vehicle's gross mass and the braking pressure data to obtain a braking force correction value; The torque output module is used to perform PID closed-loop system control calculation according to the braking torque compensation value, the braking force correction value and the brake pedal stroke data to obtain a motor torque output value.

7. An electronic device, characterized in that: The device comprises a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor implements the brake-by-wire calibration method according to any one of claims 1 to 5 when executing the computer program.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium includes a stored computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located is controlled to execute the brake-by-wire calibration method according to any one of claims 1 to 5.

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