Brake-by-wire calibration method, device and equipment

Abstract

The invention relates to the technical field of vehicle control, and discloses a brake-by-wire calibration method, device and equipment, and the method comprises the steps: obtaining the total mass of a vehicle, brake pedal travel data, vehicle speed data and brake pressure data; performing difference calculation according to the vehicle speed data to obtain a wheel speed difference; in combination with a braking distribution coefficient model, performing braking distribution calculation according to the total vehicle mass, the vehicle speed data and the wheel speed difference to obtain a braking distribution coefficient; according to the total mass of the vehicle, the brake pressure data and the brake distribution coefficient, brake torque calculation is conducted, and a brake torque compensation value is obtained; according to the total mass of the vehicle and the brake pressure data, brake force correction calculation is conducted, and a brake force correction value is obtained; according to the brake torque compensation value, the brake force correction value and the brake pedal travel data, PID closed-loop system control calculation is conducted, and a motor torque output value is obtained. According to the method, the braking force and the output torque can be accurately calculated, so that the reliability and the stability of braking are ensured.

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] At present, vehicle braking technology has become a key part of vehicle control technology to ensure vehicle safety. Although the traditional hydraulic braking system is mature and reliable, it has limitations in response speed, braking force control accuracy and energy recovery. Therefore, the wire control brake system came into being. It controls the brakes through electronic signals, replacing the traditional mechanical connection, providing faster response time and more precise braking force control.

[0003] In one prior art, the brake-by-wire system achieves braking by driving the caliper through a motor. The main controller obtains the target braking force of the left and right calipers by looking up the table according to the brake pedal travel signal and the pre-set basic MAP diagram. This system can better adapt to active brake energy recovery because it can adjust the braking force provided by the motor according to the state during braking to meet actual needs. However, when the brake-by-wire system recovers brake energy, there is a deviation between the actual braking force provided by the motor and the target braking force. In addition, when the anti-lock braking system is activated, the braking force of the whole vehicle deviates from the target braking force because the braking force of each wheel needs to be redistributed. When the brake temperature is high, the brake friction coefficient decreases, and a larger basic braking force is required to achieve the final braking force.

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

[0006] In a first aspect, in order to solve the above technical problem, 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 difference calculation according to the vehicle speed data to obtain wheel speed difference;

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

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

[0011] Performing a braking force correction calculation according to the vehicle gross mass and the braking 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 travel data to obtain a motor torque output value.

[0013] In an optional implementation manner, the acquiring of the vehicle gross mass, brake pedal travel data, vehicle speed data and brake pressure data includes:

[0014] Acquire brake pressure data through pressure sensor;

[0015] Acquiring 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 manner, performing difference calculation according to 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 implementation, 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:

[0023] The brake distribution coefficient is calculated by 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 implementation manner, the calculating the braking torque according to 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 according to the braking force and the total mass of the vehicle;

[0029] Calculate 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, and F μ (t) is the braking force and L is the wheelbase length.

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

[0035] Calculating a road adhesion coefficient according to the brake pressure data and a preset coefficient;

[0036] Calculating the vehicle deceleration according to the total mass of the vehicle, the road adhesion coefficient and the brake pressure data;

[0037] Calculating the braking force error according to the vehicle deceleration and the braking pressure data to obtain a braking force difference;

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

[0039] Among them, 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 mass of the vehicle, and 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 implementation, performing PID closed-loop system control calculation according to the braking torque compensation value, the braking force correction value and the brake pedal travel data to obtain the motor torque output value includes:

[0045] According to the brake pedal travel data, multiplying by a constant coefficient, the actual braking force is obtained;

[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 a 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, used to acquire vehicle gross mass, brake pedal travel data, vehicle speed data and brake pressure data;

[0052] A wheel speed difference calculation module, used for performing difference calculation according to the vehicle speed data to obtain the wheel speed difference;

[0053] a distribution coefficient calculation module, used to combine a braking distribution coefficient model, perform braking distribution calculation according to the total mass of the vehicle, the vehicle speed data and the wheel speed difference, and obtain a braking distribution coefficient;

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

[0055] A braking force calculation module, used to perform braking force correction calculation according to the total mass of the vehicle 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 the 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, wherein the computer-readable storage medium 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 calibration methods for wire control braking.

[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 difference calculation according to the vehicle speed data to obtain the wheel speed difference; combining with a brake distribution coefficient model, performing brake distribution calculation according to the total vehicle mass, the vehicle speed data and the wheel speed difference to obtain a brake distribution coefficient; performing brake torque calculation according to the total vehicle mass, the brake pressure data and the brake distribution coefficient to obtain a brake torque compensation value; performing brake force correction calculation according to the total vehicle mass and the brake pressure data to obtain a brake force correction value; performing PID closed-loop system control calculation according to 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 obtained in real time through sensors to ensure the accuracy of input data. Using PID control and brake correction mechanism, 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. Comprehensively considering factors such as road adhesion, vehicle gross mass, brake pressure, wheel speed difference, etc., it can handle different driving environments and road conditions to ensure the robustness of the system. By distributing the braking force of the front and rear wheels and adjusting the braking parameters according to the actual situation, it is ensured that some wheels will not be over-braked or slipped in extreme cases, thereby ensuring the braking stability and safety of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0063] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are 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 according to the vehicle speed data to obtain a wheel speed difference;

[0067] S13, combining a braking distribution coefficient model, performing braking distribution calculation according to the total vehicle 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 mass of the vehicle, the braking pressure data and the braking distribution coefficient to obtain a braking torque compensation value;

[0069] S15, performing a braking force correction calculation according to the vehicle gross mass and the braking 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 travel 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 the gross vehicle mass refers to the weight of the vehicle, including the total weight of all components such as the body, engine, fuel, passengers, cargo, etc. The gross vehicle mass is a key parameter for calculating the performance of the braking system, which can be measured using a vehicle electronic weighing system or a pressure sensor. Brake pedal travel refers to the distance the pedal moves from the time the driver presses the brake pedal to the time the braking system starts working. It can reflect the responsiveness of the braking system. A long travel indicates a problem with the braking system. Brake pedal travel data is obtained through a brake pedal displacement sensor. Brake pressure data refers to the pressure applied to the brake by the hydraulic or pneumatic pressure in the braking system. It is an important indicator for measuring the strength and reaction speed of the braking system. The higher the brake pressure, the stronger the braking force.

[0074] In step S12, a difference calculation is performed based on the vehicle speed data to obtain the 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 It is the wheel speed of the left rear wheel, which can be obtained by the wheel speed sensor installed on the left front wheel, such as magnetic encoder, optical encoder, etc. The vehicle's handling and stability depend on the coordination of the four wheels. If the wheel speed difference between the wheels is greater than 3 meters per second, it means that the vehicle's traction is uneven or slippage has occurred. When the wheel speed difference between the left rear wheel and the right rear wheel is greater than 2m / s, it can be judged that there are problems such as side slip 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 difference reflects the difference in traction between different wheels, which is crucial to preventing wheelslip and wheel loss of traction. Through the difference in traction, the control system can automatically adjust the braking system to ensure the stability of the vehicle. As an important indicator of the dynamic behavior of the vehicle, wheel speed difference can reveal problems such as slippage and stalling of the vehicle during braking, and provide early warning or intervention. By analyzing the wheel speed difference between the front and rear wheels, the vehicle can distribute the braking force more accurately, especially in complex driving environments, such as slippery roads, emergency braking, etc., to ensure that each wheel can work normally and avoid loss of control.

[0081] In step S13, a 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 a braking distribution coefficient.

[0082] In one implementation, the braking distribution coefficient is calculated by 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 braking 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 is 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 , which 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 to improve braking stability, safety and comfort. This factor is mainly used to reflect 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 degree of 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 according to the design of the vehicle, experimental data and specific braking system characteristics. In a dynamic system, k can be adjusted according to wheel speed, brake pressure, etc. through real-time feedback. The role of k is to adjust the braking force distribution between the front and rear wheels according to the speed of the vehicle. When the vehicle speed is high, the front wheels need to bear more 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 current speed of the vehicle. It reflects the state of motion of the vehicle and directly affects how the vehicle's braking system distributes braking force. The faster the vehicle is, the longer the required braking distance is usually, so the braking distribution will also be adjusted. The vehicle speed can be obtained through the vehicle's speed sensor, such as GPS speedometer, vehicle speed sensor, etc. The speed of the vehicle is used as one of the input parameters to affect the calculation of the brake distribution coefficient model. In the brake distribution formula, speed works together with the adaptive factor to adjust the brake force distribution between the front and rear wheels. Vehicle speed is an important factor affecting brake distribution. At high speeds, in order to avoid brake imbalance, the system will distribute more braking force to the front axle. At low speeds, the system will adjust to a more even brake distribution to improve comfort and control accuracy.

[0088] The model determines the brake distribution coefficient by the difference in wheel speed, the difference between the front and rear wheels. The ratio between the front wheel speed difference and the rear wheel speed difference indicates the difference in stability between the front and rear axles of the vehicle. When the wheel speed difference of the front wheels is greater than that of the rear wheels, the front axle will bear more braking force. The model can adjust the brake distribution according to the speed of the vehicle. As the speed of the vehicle increases, the braking burden of the front wheels increases, thereby ensuring the stability and controllability of the vehicle at high speeds. With this model, the vehicle is able to dynamically adjust the brake distribution according to the current driving state, ensuring that the braking system maintains optimal performance under various driving conditions.

[0089] In step S14, the braking torque is calculated according to the total mass of the vehicle, 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] Calculate 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, and F μ (t) is the braking force and L is the wheelbase length.

[0096] It should be noted that T motor It is the braking torque compensation value, which is the braking torque compensation value that the motor needs to output. It can be adjusted according to the total braking demand of the vehicle and the braking distribution of the front and rear axles to ensure that the correct braking force is applied to each wheel. The braking torque compensation value is used to adjust the braking force output of the motor to ensure that the torque distribution during braking is reasonable. The braking torque compensation value is the key to the vehicle's ability to decelerate smoothly and evenly. It ensures that the braking force distribution of the front and rear axles meets the dynamic needs of the vehicle, especially in emergency braking and complex road conditions, to prevent the vehicle from losing control or yaw.

[0097] Frear is the brake distribution coefficient of the rear axle, which indicates the proportion of the braking force that the rear axle should share. The rear axle brake distribution coefficient reflects the demand for rear axle braking and is dynamically adjusted according to the vehicle's motion state. The rear axle brake distribution coefficient is used in conjunction with the total brake torque to calculate the brake torque of the rear axle and ultimately adjust the motor's brake output. The rear axle brake distribution coefficient helps maintain vehicle stability, especially in sudden braking or slipping situations. Excessive rear axle braking force can cause the rear wheels to lock, while too little braking force can result in insufficient vehicle deceleration, affecting safety.

[0098] T req Indicates the total braking torque, which represents the braking demand of the vehicle under the current driving state. It is determined by factors such as the total mass of the vehicle, braking force, and road adhesion. req It is used to calculate the actual braking torque of each axle and finally adjust the output torque of the motor. The total braking torque is the basis for determining the overall braking demand of the vehicle. It reflects the current deceleration demand of the vehicle and directly affects the design and control of the braking system. Accurately calculating the total braking torque can ensure that the braking system can provide sufficient braking force to stop the vehicle safely under any circumstances.

[0099] m is the gross mass of the vehicle, which is the combined weight of the vehicle and all of its loads. It 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 ability to decelerate. The greater the mass, the greater the braking force required, so mass is an important factor in the calculation of braking torque. The mass of the vehicle directly affects the design of the braking system, as heavier vehicles require more braking torque to achieve the same deceleration. Therefore, accurately calculating the gross vehicle mass is critical to designing an effective braking system.

[0100] g is the gravitational acceleration of the earth, which is 9.81 m / s 2 It is used to calculate the braking torque required for the vehicle. The gravitational acceleration converts mass into a corresponding gravitational force, since the braking force depends on the mass of the vehicle acting against the gravitational force. It helps ensure that the calculated braking torque matches the actual physical requirement.

[0101] F μ (t) is the braking force, which refers to the friction between the vehicle and the ground. The ground adhesion is measured by a brake pressure sensor or a slip sensor, or estimated based on the road conditions. Friction is related to the adhesion of the tires and directly affects the braking effect. Friction is the basis for determining braking efficiency, and higher friction can provide stronger braking performance. The control system needs to consider the impact of different road adhesion changes on the vehicle's braking force in order to optimize the response of the braking system.

[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 leads to faster response but is more prone to instability. These parameters work together through a formula to accurately calculate the braking needs of the vehicle under different operating conditions. By calculating the total braking torque and the braking distribution coefficients of the front and rear axles, the braking system can dynamically adjust the braking force of each wheel to achieve a more efficient and safer braking effect.

[0103] In step S15, a braking force correction calculation is performed according to the vehicle gross mass and the braking 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 the vehicle deceleration according to the total mass of the vehicle, the road adhesion coefficient and the brake pressure data;

[0106] Calculating the braking force error according to the vehicle deceleration and the braking pressure data to obtain a braking force difference;

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

[0108] Among them, 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 mass of the vehicle, and 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 friction coefficient between the vehicle tire and the road surface, which indicates the adhesion between the tire and the ground. It is a key factor affecting braking performance, because the greater the friction, the stronger the braking effect. The road adhesion coefficient is calculated using brake pressure data and a preset coefficient. As a quantitative representation of road adhesion, μ directly affects the braking effect. It is used together with the vehicle's deceleration and other parameters to further calculate the vehicle's braking performance and correction value. The road adhesion coefficient has a great impact on vehicle braking. A high adhesion coefficient means a stronger braking effect, while a low adhesion coefficient will lead to inefficient braking and even vehicle loss of control. Therefore, real-time calculation of the road adhesion coefficient is crucial to ensure braking safety.

[0114] a is the deceleration of the vehicle during braking, which is determined by the vehicle's total mass, brake pressure, road adhesion coefficient, and other dynamic factors. The degree of vehicle deceleration will affect the subsequent calculation of the braking force. It can be used with other parameters such as brake pressure and speed to help calculate the brake force correction value to further optimize the braking effect. The vehicle's deceleration is a key factor affecting braking efficiency and vehicle stability. The greater the deceleration, the more the vehicle loses speed per unit time, and vice versa, it takes more time to stop. Therefore, accurate calculation of the vehicle's deceleration is crucial to optimizing braking performance.

[0115] ΔF μ The braking force difference indicates the deviation between the actual braking force and the ideal braking force during braking. The braking force difference is used to further calculate the braking force correction value. It helps adjust the response of the braking system to correct braking errors caused by various reasons, such as changes in road adhesion, sensor errors, etc. The braking force difference is an indicator used to measure the gap between the actual braking force and the target braking force. By optimizing the braking force difference, the system can adjust the braking output more accurately, thereby improving braking performance and driving safety.

[0116] F μ is the braking force correction value. The corrected braking force indicates the braking force actually applied to the vehicle after taking into account the braking force difference. It is to compensate and correct the braking force to ensure that the vehicle has appropriate braking performance under different driving conditions. μ As a corrected braking force, it will directly affect the vehicle's deceleration process and ensure the vehicle's stable braking response under different road conditions. It will be used to adjust the control instructions of the motor or actuator to optimize the braking effect. By calculating the braking force correction value, the system can dynamically adjust the response of the braking system to compensate for the inconsistent braking force caused by various factors, such as changes in road adhesion and sensor errors. The ultimate goal is to ensure that the vehicle can achieve smooth and stable braking under any conditions.

[0117] This model helps adjust the performance of the braking system in real time by taking into account factors such as friction coefficient and deceleration, ensuring that the vehicle can provide smooth and efficient braking under various driving conditions. By calculating the road adhesion coefficient, deceleration, braking force difference and correction value, the system can dynamically respond to different road surfaces and environmental changes, thereby optimizing braking performance and ensuring driving safety.

[0118] In step S16, 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 travel 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 a 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 should be noted that in this implementation, PID control is used to dynamically adjust the torque output of the motor to accurately control the behavior of the braking system. PID control is a feedback control mechanism that uses three parts: proportional, integral, and differential to comprehensively consider the current error, the accumulation of past errors, and the rate of change of the error to adjust the braking system.

[0125] The brake pedal travel data indicates the distance the driver has pressed the brake pedal. This data is a direct indicator of the braking force the driver intends to apply. This data is obtained through a displacement sensor installed on the brake pedal. The sensor is a potentiometer or displacement sensor that can detect the distance the pedal has moved in real time. The brake pedal travel data is multiplied by a constant coefficient to obtain the actual braking force. The brake pedal travel is a direct input to the braking operation, which directly corresponds to the driver's driving intention. Therefore, accurate brake pedal travel data is very important for precise control of the braking system.

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

[0127] The actual braking force is the braking force applied by the driver through the brake pedal. It is proportional to the brake pedal travel and the constant coefficient. The actual braking force is compared with the braking force correction value to calculate the braking error value and used as input in PID control to adjust the motor output. The actual braking force is the driver's control input and indicates the degree to which the driver expects the vehicle to slow down. Accurately obtaining the actual braking force is the basis for subsequent control steps.

[0128] The brake error value is the difference between the actual braking force and the ideal braking force. It represents the error in the current vehicle deceleration process. The brake error value is one of the inputs of PID control. Through feedback adjustment of the error, the PID controller dynamically adjusts the motor torque output to eliminate the brake error. The brake error value directly reflects the performance of the brake system. When the error value is greater than 3, it means that the system fails to correctly execute the driver's intention, and the PID control can be adjusted to reduce this error.

[0129] The brake torque compensation value is calculated by the control system to adjust the torque output by the motor 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. The brake torque compensation value, together with the adjustment result of the PID control output, determines the final output torque of the motor and adjusts the braking response of the vehicle. This value ensures precise control of the brake system, especially in dynamic environments, and can effectively eliminate the interference of external factors on the braking effect.

[0130] The PID controller is a feedback control mechanism that adjusts the error through proportional, integral and differential parts to ensure that the system output reaches the desired target. The PID controller requires setting three gain coefficients: proportional gain, integral gain and differential gain. These gain coefficients are obtained through experiments or adjustments. The goal of the PID controller is to minimize the braking error by dynamically adjusting the motor torque to ensure that the vehicle's braking system can respond accurately and smoothly to the driver's operation. The proportional term solves the current error, the integral term corrects the accumulated error, and the differential term offsets the trend of the error change.

[0131] This control strategy comprehensively considers the braking error, braking correction value and motor torque compensation, and combines PID control to accurately adjust the motor output to ensure stable braking performance of the vehicle under different working conditions. Specifically, through the feedback of the braking error, PID control can optimize the torque output of the motor and achieve fine control of the braking process, thereby improving driving safety and the smoothness of the braking response.

[0132] In summary, the present invention discloses a calibration method for wire control braking, including obtaining the total mass of the vehicle, brake pedal travel data, vehicle speed data and brake pressure data; performing difference calculation based on the vehicle speed data to obtain the wheel speed difference; 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 differentiated movement between the wheels. By accurately calculating the braking distribution coefficient, the system can flexibly distribute the braking force of the front and rear wheels according to the changes in the wheel speed difference and vehicle speed. This dynamic braking distribution can not only ensure the balance of braking performance, but also prevent excessive braking or slipping of a certain wheel, thereby improving braking stability and safety.

[0133] The pedal travel is converted into actual braking force through a preset constant coefficient, ensuring that the driver's intention is correctly mapped to the vehicle's actual braking response. The constant coefficient can be adjusted according to different vehicles and braking systems to achieve more precise control.

[0134] Combined with the brake distribution coefficient model, the brake distribution calculation is performed according to the total vehicle mass, the vehicle speed data and the wheel speed difference to obtain the brake distribution coefficient; the brake torque is calculated according to the total vehicle mass, the brake pressure data and the brake distribution coefficient to obtain the brake torque compensation value; the brake force correction calculation is performed according to the total vehicle mass and the brake pressure data to obtain the brake force correction value; the PID closed-loop system control calculation is performed according to the brake torque compensation value, the brake force correction value and the brake pedal stroke data to obtain the motor torque output value. This feedback mechanism can continuously adjust the motor torque, fine-tune the response of the brake system, and eliminate errors caused by system delays, nonlinearities or external factors such as road conditions.

[0135] The brake torque compensation value in this method is calculated based on multiple factors, such as brake pressure, brake distribution coefficient, road adhesion coefficient, etc. By considering multiple dynamic factors, the system can more accurately determine and adjust the required braking force. For example, factors such as vehicle deceleration, brake 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 slippery or icy roads, the adhesion coefficient will be significantly reduced. By calculating the road adhesion coefficient and performing brake corrections, the system can adjust the braking strategy to ensure safe and stable braking 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, used to acquire vehicle gross mass, brake pedal travel data, vehicle speed data and brake pressure data;

[0138] A wheel speed difference calculation module, used for performing difference calculation according to the vehicle speed data to obtain the wheel speed difference;

[0139] a distribution coefficient calculation module, used to combine a braking distribution coefficient model, perform braking distribution calculation according to the total mass of the vehicle, the vehicle speed data and the wheel speed difference, and obtain a braking distribution coefficient;

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

[0141] A braking force calculation module, used to perform braking force correction calculation according to the total mass of the vehicle 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 the motor torque output value.

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

[0144] The 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 in 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 each module / unit 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, which 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, a notebook, a PDA, and a smart tablet. The electronic device may include, but is not limited to, a processor and a memory. Those skilled in the art will appreciate that the above components are merely examples of electronic devices and do not constitute a limitation on the electronic device. The electronic device may include more or fewer components than the above components, or may combine certain components, or different components. For example, the electronic device may also include input and output devices, network access devices, buses, etc.

[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, and uses various interfaces and lines to connect various parts of the entire electronic device.

[0148] The memory can be used to store the computer program and / or module, and the processor realizes various functions of the electronic device by running or executing the computer program and / or module 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, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area can store data created according to the use of the mobile phone (such as audio data, a phone book, etc.), 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 devices.

[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 such an understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. 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, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), 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 schematic, 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 on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, in the accompanying 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 may understand and implement it without paying any creative effort.

[0151] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

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 difference calculation according to the vehicle speed data to obtain wheel speed difference; In combination with a braking distribution coefficient model, a braking distribution calculation is performed according to the total vehicle mass, the vehicle speed data and the wheel speed difference to obtain a braking distribution coefficient; Calculating the braking torque according to the total mass of the vehicle, the braking pressure data and the braking distribution coefficient to obtain a braking torque compensation value; Performing a braking force correction calculation according to the vehicle gross mass and the braking pressure data to obtain a braking force correction value; 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 travel data to obtain a motor torque output value.

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

3. The calibration method of brake-by-wire control according to claim 1, characterized in that: The step of performing difference calculation according to the vehicle speed data to obtain the wheel speed difference comprises: The wheel speed difference is calculated using the following formula: Δv FL =v FR -v FL Δv RL =v RR -v RL 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.

4. The brake-by-wire calibration method according to claim 1, characterized in that: 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 by the following brake distribution coefficient model: 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.

5. The brake-by-wire calibration method according to claim 1, characterized in that: The step of calculating the braking torque according to the total vehicle mass, the braking pressure data and the braking distribution coefficient to obtain the braking torque compensation value includes: The braking force is calculated by multiplying the braking pressure data by a linear coefficient, wherein the linear coefficient is a preset constant; Calculating a total braking torque according to the braking force and the total mass of the vehicle; Calculate a braking torque compensation value according to the total braking torque and the braking distribution coefficient; The calculation formula of the braking torque compensation value is as follows: T motor =T req ·F front +T req ·F rear 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, and F μ (t) is the braking force and L is the wheelbase length.

6. The brake-by-wire calibration method according to claim 1, characterized in that: The step of performing a braking force correction calculation according to the vehicle gross mass and the braking pressure data to obtain a braking force correction value includes: Calculating a road adhesion coefficient according to the brake pressure data and a preset coefficient; Calculating the vehicle deceleration according to the total mass of the vehicle, the road adhesion coefficient and the brake pressure data; Calculating the braking force error according to the vehicle deceleration and the braking pressure data to obtain a braking force difference; Calculating a braking force correction value according to the braking force difference and the braking pressure data to obtain a braking force correction value; Among them, the calculation formulas for the road adhesion coefficient, vehicle deceleration, braking force difference, and braking force correction value are as follows: μ=a1P+a2 F μ =q·P+ΔF μ 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 mass of the vehicle, and 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.

7. The brake-by-wire calibration method according to claim 1, characterized in that: The step of performing PID closed-loop system control calculation according to the braking torque compensation value, the braking force correction value and the brake pedal travel data to obtain the motor torque output value includes: According to the brake pedal travel data, multiplying by a constant coefficient, the actual braking force is obtained; 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 a motor torque output value. The calculation formula of the motor torque output value is as follows: 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.

8. A brake-by-wire calibration device, characterized in that: include: A data acquisition module, used to acquire vehicle gross mass, brake pedal travel data, vehicle speed data and brake pressure data; A wheel speed difference calculation module, used for performing difference calculation according to the vehicle speed data to obtain the wheel speed difference; a distribution coefficient calculation module, used to combine a braking distribution coefficient model, perform braking distribution calculation according to the total mass of the vehicle, the vehicle speed data and the wheel speed difference, and obtain a braking distribution coefficient; a braking torque calculation module, configured to calculate the braking torque according to the total mass of the vehicle, the braking pressure data and the braking distribution coefficient, and obtain a braking torque compensation value; A braking force calculation module, used to perform braking force correction calculation according to the total mass of the vehicle 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 the motor torque output value.

9. An electronic device, characterized in that: The method 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 linear brake calibration method according to any one of claims 1 to 7 when executing the computer program.

10. 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 linear brake calibration method according to any one of claims 1 to 7.

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