Real-time clamping force zero point confirmation method, device and equipment and readable storage medium

Abstract

According to the real-time clamping force zero point confirmation method, device and equipment and the readable storage medium, in a preset triggering scene, a motor of an EMB actuator is controlled to rotate in the forward clamping direction, motor rotation angle and torque parameters are synchronously collected in real time, and a motor rotation angle-torque curve is generated; according to the characteristic difference of the torque along with the change of the rotation angle before and after contact, selecting a preset calibration torque point on the rotation angle-torque curve, constructing a tangent line through the point, and positioning an intersection point of the tangent line and a motor rotation angle coordinate axis, the intersection point corresponding to a motor rotation angle reference in a contact critical state of a friction block and a brake disc; and the current zero point of the clamping force is obtained after the reference rotation angle is superposed with the comprehensive compensation amount. Accurate capture of a contact critical position is realized through real-time detection of motor rotation angle and torque and curve characteristic analysis, dynamic drift factors are adapted in combination with comprehensive compensation quantity, and zero point real-time updating can be automatically completed in the whole life cycle of the whole vehicle without depending on a fixed calibration value.

Description

Technical Field

[0001] This application relates to the field of intelligent vehicle braking systems, specifically to a method, apparatus, device, and readable storage medium for real-time clamping force zero-point confirmation. Background Technology

[0002] Electromechanical braking (EMB), as the core solution of brake-by-wire technology, generates braking force by driving the brake actuator with an electric motor, completely replacing the fluid transmission structure of traditional hydraulic or pneumatic braking systems.

[0003] In related technologies, within the EMB system, the accurate estimation of clamping force directly determines braking performance and driving safety. The core prerequisite for clamping force estimation is accurately obtaining the "clamping force zero point," which is the critical position (also known as the "contact point") where the brake pads (friction blocks) first contact the brake disc. This zero point is the reference origin for the clamping force estimation model to take effect; all subsequent clamping force calculations must use this position as a reference. The accuracy of the zero point directly determines the upper limit of the clamping force estimation accuracy. If the zero point is confirmed to be inaccurate, even with a highly refined subsequent estimation algorithm, it will lead to distorted braking force control, causing safety hazards such as "soft braking" and "sudden changes in initial braking force."

[0004] However, most solutions use a fixed zero-point value calibrated before leaving the factory, which cannot cope with dynamic zero-point drift. As the vehicle's mileage increases, the deviation between the fixed zero point and the actual contact point will gradually widen, making it difficult to cover the real-time changes of the zero point under long-term complex driving conditions. This ultimately leads to a sharp increase in clamping force estimation error, a decrease in braking force control accuracy, and seriously affects the reliability and safety of the braking system. Summary of the Invention

[0005] This application provides a real-time clamping force zero-point confirmation method, apparatus, device, and readable storage medium, which can solve the technical problem that most solutions in related technologies use a fixed zero-point value calibrated before leaving the factory, which cannot cope with the dynamic drift of the zero point.

[0006] In a first aspect, embodiments of this application provide a method for confirming the zero point of real-time clamping force, the method comprising: Under the preset trigger scenario, the motor of the electromechanical brake actuator is controlled to rotate in the positive clamping direction, and the motor's rotation angle and torque are detected in real time and the motor rotation angle-torque curve is recorded. Select a preset calibration torque point on the motor rotation angle-torque curve, obtain the tangent at that point, and determine the intersection of the tangent with the motor rotation angle coordinate axis; The current clamping force zero point is obtained by superimposing the comprehensive compensation amount on the angle corresponding to the intersection point, thus realizing the update of the clamping force zero point. In conjunction with the first aspect, in one implementation, the step of superimposing a comprehensive compensation amount on the angle corresponding to the intersection point to obtain the current clamping force zero point, thereby updating the clamping force zero point, includes: If the preset trigger scenario is the vehicle power-on start scenario, then the angle corresponding to the intersection point is superimposed with the comprehensive compensation amount corresponding to the ambient temperature, braking system efficiency and initial friction block compression to obtain the clamping force zero point of the first braking after the vehicle is powered on and started, which serves as the benchmark for subsequent braking cycle zero point updates.

[0007] In conjunction with the first aspect, in one embodiment, determining the initial compression of the friction block includes: Based on the vehicle's cumulative mileage, and combined with the pre-calibrated friction block wear-mileage mapping relationship established by bench testing, the cumulative wear of the friction block is calculated. The initial compression amount of the friction block is obtained by subtracting the cumulative wear amount from the initial compression amount corresponding to the initial thickness of the friction block at the factory.

[0008] In conjunction with the first aspect, in one implementation, the step of superimposing a comprehensive compensation amount on the angle corresponding to the intersection point to obtain the current clamping force zero point, thereby updating the clamping force zero point, includes: If the preset trigger scenario is a vehicle driving braking scenario, the clamping force zero point for the next braking is calculated by superimposing the real-time ambient temperature, real-time system rigidity and the comprehensive compensation amount corresponding to the current friction block compression at the intersection point, thus completing the dynamic cyclic update of the clamping force zero point.

[0009] In conjunction with the first aspect, in one implementation, determining the rigidity of the real-time system includes: Substitute the real-time temperature of the brake disc into the pre-calibrated temperature-system rigidity mapping relationship of the bench test to calculate the initial value of the system rigidity at the current temperature. By combining the real-time rotation angle data of the brake motor, the initial value of the system rigidity is corrected based on the preset system rigidity-motor rotation angle compensation function, and finally the real-time system rigidity adapted to the current working conditions is obtained.

[0010] In conjunction with the first aspect, in one embodiment, determining the current compression amount of the friction block includes: Based on the vehicle's cumulative mileage, and combined with the pre-calibrated friction block wear-mileage mapping relationship established by bench testing, the cumulative wear of the friction block is calculated. The cumulative wear of the friction block, the real-time temperature of the brake disc, and the real-time rotation angle data of the current brake motor are substituted into the temperature-friction block compression characteristic mapping relationship pre-calibrated in the bench test to calculate the friction block compression under the current working condition.

[0011] In conjunction with the first aspect, in one implementation, the following steps are also included: Based on the confirmed real-time clamping force zero point, combined with the caliper clamping force stiffness curve pre-written into the system controller, the basic angle corresponding to the position of the stiffness curve is determined according to the target clamping force requested by the system. Then, the preset clamping force estimation model is retrieved to calculate the temperature compensation angle. Based on the confirmed real-time clamping force zero point, base angle, and temperature compensation angle, the total angle that the motor needs to rotate is obtained. When the motor rotates to this total angle, the output clamping force can match the target clamping force required by the system.

[0012] Secondly, embodiments of this application provide a real-time clamping force zero-point confirmation device, the real-time clamping force zero-point confirmation device comprising: The motor control and data acquisition module controls the motor of the electromechanical brake actuator to rotate in the positive clamping direction under a preset trigger scenario, and detects the motor's rotation angle and torque in real time and records the motor's rotation angle-torque curve. The tangent intersection calculation module selects a preset calibration torque point on the motor angle-torque curve, obtains the tangent at that point, and determines the intersection of the tangent with the motor angle coordinate axis. The zero-point compensation update module adds a comprehensive compensation amount to the corner corresponding to the intersection point to obtain the current clamping force zero point, thereby updating the clamping force zero point.

[0013] Thirdly, embodiments of this application provide a real-time clamping force zero-point confirmation device, which includes a processor, a memory, and a real-time clamping force zero-point confirmation program stored in the memory and executable by the processor. When the real-time clamping force zero-point confirmation program is executed by the processor, it implements the steps of the real-time clamping force zero-point confirmation method as described in some of the above embodiments.

[0014] Fourthly, embodiments of this application provide a computer-readable storage medium storing a real-time clamping force zero-point confirmation program, wherein when the real-time clamping force zero-point confirmation program is executed by a processor, it implements the steps of the real-time clamping force zero-point confirmation method as described in some of the above embodiments.

[0015] The beneficial effects of the technical solutions provided in this application include: Under a preset trigger scenario, the motor controlling the EMB actuator rotates in the forward clamping direction. Simultaneously, the motor's angle and torque parameters are collected in real time, generating a motor angle-torque curve. Utilizing the difference in torque variation with angle before and after contact as the friction block approaches the brake disc, a preset calibration torque point is selected on the angle-torque curve. A tangent is constructed at this point, and the intersection of the tangent and the motor angle coordinate axis is located. This intersection point corresponds to the motor angle reference at the critical contact state between the friction block and the brake disc. The current clamping force zero point is obtained by superimposing a comprehensive compensation amount on this reference angle, completing the zero-point update. This method achieves precise capture of the contact critical position through real-time detection of motor angle and torque and curve feature analysis. Combined with comprehensive compensation to adapt to dynamic drift factors, it does not rely on fixed calibration values ​​and can automatically complete real-time zero-point updates throughout the entire vehicle lifecycle, effectively avoiding the problem of widening deviation between the fixed zero point and the actual contact point. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating an embodiment of the real-time clamping force zero-point confirmation method of this application; Figure 2 This is a schematic diagram of the hardware structure of the real-time clamping force zero-point confirmation device involved in the embodiments of this application. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present application.

[0018] Electro-mechanical braking (EMB), as a core solution of brake-by-wire technology, generates braking force by driving a brake actuator with an electric motor, completely replacing the fluid transmission structure of traditional hydraulic or pneumatic braking systems. Its working principle is as follows: After the vehicle's brake controller collects braking requests, it distributes braking torque to all four wheels based on the vehicle's operating status. The commands are then sent to the wheel-end EMB actuators via the CAN communication channel. The actuator's internal electronic control system drives the motor to push the piston, ultimately creating frictional torque between the friction block and the brake disc. The EMB system achieves complete decoupling of the braking system, possessing significant advantages such as compact structure, rapid response, and high execution efficiency. It has become a key core component supporting the development of chassis domain control and advanced intelligent driving technologies.

[0019] In the EMB system, accurate estimation of clamping force directly determines braking performance and driving safety. The core prerequisite for clamping force estimation is accurately obtaining the "clamping force zero point," which is the critical position (also known as the "contact point") where the brake pads (friction blocks) first contact the brake disc. This zero point is the reference origin for the clamping force estimation model to take effect, and all subsequent clamping force calculations must use this position as a reference. The accuracy of the zero point directly determines the upper limit of the clamping force estimation accuracy. If the zero point is confirmed to be inaccurate, even if the subsequent estimation algorithm is perfect, it will lead to distortion of braking force control, causing safety hazards such as "soft braking" and "sudden change in initial braking force."

[0020] However, the zero point of clamping force is not a fixed mechanical position; it will dynamically drift due to various factors during vehicle operation: the wear of brake pads throughout their entire life cycle will continuously change their initial thickness; temperature changes (thermal expansion of friction blocks, cold contraction / thermal expansion of pads) will cause fluctuations in component dimensions; dynamic changes in mechanical clearance and minor deformations of system components will also affect the zero point position.

[0021] The existing clamping force zero-point confirmation schemes in EMB systems have significant limitations: most schemes use a fixed zero-point value calibrated at the factory, which cannot cope with dynamic zero-point drift. As vehicle mileage increases, the deviation between the fixed zero point and the actual contact point gradually widens, making it difficult to cover the real-time changes in the zero point under long-term complex driving conditions (such as continuous braking, switching between high and low temperature environments, and rapid lining wear). This ultimately leads to a sharp increase in clamping force estimation errors, a decrease in braking force control accuracy, and seriously affects the reliability and safety of the braking system.

[0022] Therefore, developing a real-time clamping force zero-point confirmation method that can automatically, in real-time, and accurately detect and update the clamping force zero-point position online throughout the entire vehicle lifecycle, while possessing simple algorithms, strong robustness, and ease of engineering implementation, has become the core breakthrough in solving the clamping force estimation accuracy problem of EMB systems, and has important practical significance for improving the safety and stability of brake-by-wire systems.

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0024] In a first aspect, embodiments of this application provide a method for real-time clamping force zero-point confirmation.

[0025] In one embodiment, reference is made to Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the real-time clamping force zero-point confirmation method of this application. Figure 1 As shown, the real-time clamping force zero-point confirmation method includes: S100: Under a preset trigger scenario, the motor of the electromechanical brake actuator is controlled to rotate in the positive clamping direction, and the motor's rotation angle and torque are detected in real time and the motor rotation angle-torque curve is recorded. S200: Select a preset calibration torque point on the motor rotation angle-torque curve, obtain the tangent at that point, and determine the intersection of the tangent with the motor rotation angle coordinate axis; S300: The angle corresponding to the intersection point is superimposed with the comprehensive compensation amount to obtain the current clamping force zero point, thereby updating the clamping force zero point.

[0026] In this embodiment, under a preset triggering scenario, the motor of the EMB actuator is controlled to rotate in the forward clamping direction. Simultaneously, the motor angle and torque parameters are collected in real time, generating a motor angle-torque curve. Utilizing the difference in torque variation with angle before and after contact as the friction block approaches the brake disc, a preset calibration torque point is selected on the angle-torque curve. A tangent is constructed at this point, and the intersection of the tangent and the motor angle coordinate axis is located. This intersection point corresponds to the motor angle reference at the critical contact state between the friction block and the brake disc. The current clamping force zero point is obtained by superimposing a comprehensive compensation amount on this reference angle, completing the zero point update. This method achieves accurate capture of the contact critical position through real-time detection of motor angle and torque and curve feature analysis. Combined with the comprehensive compensation amount to adapt to dynamic drift factors, it does not rely on fixed calibration values ​​and can automatically complete real-time zero point updates throughout the entire vehicle lifecycle. This effectively avoids the problem of increased deviation between the fixed zero point and the actual contact point, improves the clamping force estimation accuracy to ensure braking force control stability, and the overall process is simple, robust, and easy to integrate into engineering applications.

[0027] The preset calibration torque point refers to a specific motor torque output value that is pre-calibrated through bench testing before the EMB system leaves the factory and stored in the system controller, as well as its unique coordinate point (including torque value and corresponding angle value) on the motor angle-torque curve. The calibration of this torque point needs to be determined based on the mechanical characteristics of the EMB actuator and the contact characteristics between the friction block and the brake disc, within the transition range between the "free stroke stage when the friction block is not in contact with the brake disc" and the "torque increase stage after the friction block contacts the brake disc", so as to ensure that the point can stably reflect the critical transition state of "the friction block is about to contact the brake disc but has not fully contacted it".

[0028] Furthermore, in one embodiment, step S300 includes the following steps: S301: If the preset trigger scenario is the vehicle power-on start scenario, the angle corresponding to the intersection point is superimposed with the ambient temperature, braking system efficiency and the comprehensive compensation amount corresponding to the initial friction block compression to obtain the clamping force zero point of the first braking after the vehicle is powered on and started, which is used as the benchmark for the zero point update of the subsequent braking cycle.

[0029] In this embodiment, when the preset trigger scenario is the vehicle power-on start scenario, after obtaining the angle corresponding to the intersection of the tangent of the preset calibration torque point on the motor angle-torque curve and the motor angle coordinate axis, the angle corresponding to the intersection point is superimposed with the comprehensive compensation amount corresponding to the ambient temperature, braking system efficiency and initial friction block compression to obtain the clamping force zero point required for the first braking process after the vehicle power-on start. The clamping force zero point of the first braking after the vehicle power-on start is configured as the benchmark for the clamping force zero point update operation in subsequent braking cycles.

[0030] Furthermore, in one embodiment, the comprehensive compensation amount is calculated based on the core dynamic factors affecting the zero point of the clamping force throughout the entire life cycle of the EMB system (ambient temperature T, system efficiency η, and friction block compression δ), through coupling the pre-calibrated model with real-time parameters. The specific calculation logic is as follows: First, the ambient temperature compensation term obtains the real-time brake disc temperature T through a temperature sensor, calls the temperature compensation function α(T) pre-stored in the controller (this function is calibrated by bench testing and covers the influence of system rigidity changes and friction block thermal expansion coefficients on the steering angle at different temperatures, such as α(T) = k1 × T + k2, where k1 and k2 are temperature coefficients calibrated by the bench test), and generates the steering angle compensation component Δθ corresponding to the temperature. T =α(T); Secondly, the system efficiency compensation term is based on a pre-calibrated system efficiency model (stored in memory, the correlation between η and T, and the cumulative wear of the friction block measured by bench tests under different temperatures and wear conditions). It calls the efficiency coefficient η corresponding to the current temperature T and the wear state of the friction block recorded in the previous braking cycle in real time to generate the efficiency compensation component Δθ. η =k3×(1-η), where k3 is the efficiency influence coefficient (determined by bench calibration). Finally, the friction block compression compensation term is based on the pre-established friction block compression model δθ=δ(θ+α(T)) (θ is the motor rotation angle of the previous braking cycle), combined with the compression characteristics at the current temperature T, and the real-time friction block compression δ is derived by back-calculating the motor rotation angle and torque curve of the previous braking cycle, thus generating the compression compensation component Δθ. δ =δ×k4, where k4 is the compression-rotation angle conversion coefficient (calibrated by bench test, reflecting the correspondence between the friction block compression and the motor rotation angle); the comprehensive compensation is the coupled superposition of the above three compensation components, i.e., offset(T+η+δ)=Δθ T +Δθ η +Δθ δ The weights and coupling algorithms of each component are calibrated in the full operating range through bench tests. The relevant calibration parameters and models are pre-stored in the system memory. During calculation, the controller calls real-time sensor data (temperature T, previous cycle rotation angle θ) and pre-stored model parameters to automatically complete the compensation calculation.

[0031] Furthermore, in one embodiment, step S301 includes the following steps: S301-1: Based on the vehicle's cumulative mileage and combined with the pre-calibrated friction block wear-mileage mapping relationship from bench tests, the cumulative wear of the friction block is calculated. S301-2: Based on the compression amount corresponding to the initial thickness of the friction block at the factory, subtract the cumulative wear amount to obtain the initial compression amount of the friction block.

[0032] In this embodiment, the friction block wear amount-mileage mapping relationship, which is pre-stored in the system controller and pre-calibrated by bench test, is called. Combined with the cumulative mileage recorded in real time by the vehicle, the cumulative wear amount of the friction block is calculated through the mapping relationship. The compression amount corresponding to the initial thickness of the friction block when it leaves the factory is used as the reference value. The cumulative wear amount of the friction block calculated above is subtracted from the reference value to obtain the initial friction block compression amount used for comprehensive compensation calculation.

[0033] For example, 1. The formula for calculating the cumulative wear of the friction block is:

[0034] in, The cumulative wear of the friction block is measured in mm; L represents the cumulative mileage recorded in real time by the vehicle (in km). This refers to the friction block wear amount-mileage mapping function pre-stored in the system controller and calibrated through bench testing (this function is obtained by fitting through full life cycle wear tests, such as a linear function). or nonlinear function , where k n b n (where n is the wear characteristic coefficient calibrated on the test bench).

[0035] 2. The initial friction block compression is calculated using the following formula:

[0036] in, The initial friction block compression amount (unit: mm) is used for comprehensive compensation calculation. The compression amount corresponding to the initial thickness of the friction block at the factory (unit: mm, is the factory standard amount, determined by the initial physical thickness and pre-compression characteristics of the friction block). The cumulative wear of the friction block calculated in the aforementioned steps.

[0037] Furthermore, in one embodiment, step S300 includes the following steps: S302: If the preset trigger scenario is a vehicle driving braking scenario, the clamping force zero point of the next braking is calculated by superimposing the real-time ambient temperature, real-time system rigidity and the comprehensive compensation amount corresponding to the current friction block compression amount at the intersection point, and the clamping force zero point is dynamically and cyclically updated.

[0038] In this embodiment, when the preset trigger scenario is a vehicle driving braking scenario, after obtaining the angle corresponding to the intersection of the tangent of the preset calibration torque point on the motor angle-torque curve and the motor angle coordinate axis, the angle corresponding to the intersection point is superimposed with the comprehensive compensation amount corresponding to the real-time collected ambient temperature, the real-time calculated system rigidity and the friction block compression amount under the current working condition to obtain the clamping force zero point for the next braking cycle, thereby completing the dynamic cyclic update of the clamping force zero point during vehicle driving.

[0039] Furthermore, in one embodiment, step S302 includes the following steps: S302-1: Substitute the real-time temperature of the brake disc into the pre-calibrated temperature-system rigidity mapping relationship of the bench test to calculate the initial value of the system rigidity at the current temperature; S302-2: Combining the real-time rotation angle data of the current braking motor, the initial value of the system rigidity is corrected based on the preset system rigidity-motor rotation angle compensation function, and finally the real-time system rigidity adapted to the current working condition is obtained.

[0040] In this embodiment, the real-time temperature of the brake disc is collected and substituted into the temperature-system rigidity mapping relationship pre-stored in the system controller and pre-calibrated by bench testing. The initial value of system rigidity under the current temperature condition is calculated through this mapping relationship. Then, combined with the real-time rotation angle data of the motor during the current braking process, the initial value of system rigidity obtained above is corrected according to the system rigidity-motor rotation angle compensation function pre-stored in the system. Finally, the real-time system rigidity adapted to the current braking condition is obtained.

[0041] For example, 1. The formula for calculating the initial value of system stiffness at the current temperature is:

[0042] in, The initial system rigidity value corresponding to the current brake disc temperature (unit: N / mm); T is the brake disc temperature collected in real time by the temperature sensor (unit: °C). The temperature-system stiffness mapping function, pre-stored in the system controller and calibrated through bench testing (this function is obtained by fitting system stiffness data from bench tests under different temperature conditions and can be a linear function), is used. or nonlinear function , where k T b T(where n is the temperature-rigidity coefficient of the test bench).

[0043] 2. The real-time system rigidity calculation formula adapted to the current operating conditions is as follows:

[0044] in, Real-time system stiffness (unit: N / mm) to adapt to the current braking conditions. The initial values ​​of system rigidity calculated in the aforementioned steps; This refers to the motor angle data (unit: ° or rad) collected in real time by the motor angle sensor during the current braking process. The system rigidity-motor angle compensation function is pre-installed in the system (this function is calibrated by bench tests and is used to correct the influence of motor angle changes on system rigidity, such as transmission mechanism deformation, changes in frictional contact state, etc., and its form can be set as follows). ,in (The rotation compensation coefficient calibrated for the test bench).

[0045] Furthermore, in one embodiment, step S302 includes the following steps: S302-3: Based on the vehicle's cumulative mileage and combined with the pre-calibrated friction block wear-mileage mapping relationship from bench tests, the cumulative wear of the friction block is calculated. S302-4: Substitute the cumulative wear of the friction block, the real-time temperature of the brake disc, and the real-time rotation angle data of the current brake motor into the temperature-friction block compression characteristic mapping relationship pre-calibrated in the bench test to calculate the friction block compression under the current working condition.

[0046] In this embodiment, the friction block wear amount-mileage mapping relationship, which is pre-stored in the system controller and pre-calibrated through bench testing, is invoked. Combined with the cumulative mileage recorded in real time by the vehicle, the cumulative wear amount of the friction block is calculated through this mapping relationship. The aforementioned cumulative wear amount of the friction block, the real-time temperature of the brake disc, and the real-time rotation angle data of the motor during the current braking process are substituted into the temperature-friction block compression characteristic mapping relationship, which is pre-stored in the system controller and pre-calibrated through bench testing. The friction block compression amount under the current braking condition is calculated through this mapping relationship.

[0047] For example, 1. The formula for calculating the cumulative wear of the friction block is:

[0048] in, The cumulative wear of the friction block is measured in mm; L represents the cumulative mileage recorded in real time by the vehicle (in km). This refers to the friction block wear amount-mileage mapping function pre-stored in the system controller and calibrated through bench testing (this function is obtained by fitting through full life cycle wear condition bench testing, and can be in the form of a linear function). or nonlinear function , where k w b w , n are the wear characteristic coefficients calibrated on the test bench, used to characterize the wear rate of the friction block under different mileages.

[0049] 2. The formula for calculating the compression of the friction block under the current operating conditions is:

[0050] in, This represents the compression of the friction block under the current braking condition (unit: mm). The cumulative wear of the friction block is calculated in the aforementioned steps; T is the brake disc temperature (unit: °C) collected in real time by a temperature sensor. This refers to the motor angle data (unit: ° or rad) collected in real time by the motor angle sensor during the current braking process. The temperature-friction block compression characteristic multivariate mapping function is pre-stored in the system controller and calibrated by bench test (this function is obtained by fitting the friction block compression data tested on the bench under different temperatures, wear amounts, and motor rotation angles, and is used to couple and correct the friction block thickness change caused by cumulative wear, the friction block thermal expansion / contraction caused by temperature, and the actual compression stroke deviation corresponding to the motor rotation angle, to ensure that the compression calculation is adapted to the current dynamic working conditions).

[0051] Furthermore, in one embodiment, after S300, there is also S400, which includes the following steps: S401: Based on the confirmed real-time clamping force zero point, combined with the caliper clamping force stiffness curve pre-written into the system controller, the basic angle corresponding to the position of the stiffness curve is determined according to the target clamping force requested by the system, and then the preset clamping force estimation model is retrieved to calculate the temperature compensation angle. S402: Based on the confirmed real-time clamping force zero point, base angle and temperature compensation angle, the total angle that the motor needs to rotate is obtained. When the motor rotates to this total angle, the output clamping force can match the target clamping force required by the system.

[0052] In this embodiment, based on the confirmed real-time clamping force zero point, the caliper clamping force stiffness curve pre-written into the system controller is invoked. According to the target clamping force requested by the system, the base angle at the corresponding position is located and determined on the stiffness curve. Then, the clamping force estimation model pre-installed in the system is retrieved, and the temperature compensation angle is calculated through the model. Using the confirmed real-time clamping force zero point as a reference, the base angle and the temperature compensation angle are superimposed to obtain the total angle that the motor needs to rotate. When the motor is controlled to rotate to this total angle, the clamping force output by the motor-driven braking actuator can match the target clamping force required by the system.

[0053] For example, 1. Basic perspective The calculation formula is:

[0054] The stiffness curve corresponds to the basic angle of the target clamping force (unit: ° or rad), representing "the difference in rotation angle from the zero point of clamping force to the theoretical angle corresponding to the target clamping force"; : Pre-stored caliper clamping force stiffness curve function (bench calibration, input is motor rotation angle, output is the corresponding clamping force, i.e.) ); The inverse function of the stiffness curve (input is the target clamping force) The output is the absolute motor rotation angle corresponding to the clamping force. The system requests the target clamping force (in N). : Confirmed real-time clamping force zero point (unit: ° or rad).

[0055] 2. Temperature compensation angle The calculation formula is:

[0056] Temperature compensation angle (unit: ° or rad) is used to correct for changes in system rigidity caused by temperature and the effect of thermal expansion of friction blocks on the rotation angle. The clamping force estimation model incorporates a temperature compensation algorithm (bench calibration, inputs are real-time brake disc temperature T, target clamping force (F_{\text{target}}\) and current system rigidity (K_{\text{sys}}\), output is the compensation angle). T: Real-time temperature of the brake disc (unit: °C, collected by a temperature sensor); Real-time system stiffness under current operating conditions (unit: N / mm, calculated according to step S302).

[0057] 3. Total motor rotation angle Calculation formula

[0058] The total angle that the motor needs to rotate (unit: ° or rad), that is, the absolute angle position that the motor finally needs to reach.

[0059] Secondly, this application also provides a real-time clamping force zero-point confirmation device, which includes: a motor control and data acquisition module, which controls the motor of the electromechanical brake actuator to rotate in the positive clamping direction under a preset triggering scenario, detects the motor's rotation angle and torque in real time and records the motor rotation angle-torque curve; a tangent intersection calculation module, which selects a preset calibration torque point on the motor rotation angle-torque curve, obtains the tangent at that point and determines the intersection point of the tangent with the motor rotation angle coordinate axis; and a zero-point compensation update module, which superimposes a comprehensive compensation amount on the rotation angle corresponding to the intersection point to obtain the current clamping force zero point and realizes the update of the clamping force zero point.

[0060] The functions of each module in the real-time clamping force zero point confirmation device correspond to the steps in the real-time clamping force zero point confirmation method embodiment, and their functions and implementation processes will not be described in detail here.

[0061] Thirdly, embodiments of this application provide a real-time clamping force zero-point confirmation device, which can be a device with data processing capabilities such as a personal computer (PC), a laptop, or a server.

[0062] Reference Figure 2 , Figure 2 This is a schematic diagram of the hardware structure of the real-time clamping force zero-point confirmation device involved in the embodiments of this application. In the embodiments of this application, the real-time clamping force zero-point confirmation device may include a processor, a memory, a communication interface, and a communication bus.

[0063] The communication bus can be of any type and is used to interconnect the processor, memory, and communication interface.

[0064] The communication interface includes input / output (I / O) interfaces, physical interfaces, and logical interfaces for interconnecting internal components of the real-time clamping force zero-point confirmation device, as well as interfaces for interconnecting the real-time clamping force zero-point confirmation device with other devices (such as other computing devices or user equipment). Physical interfaces can be Ethernet interfaces, fiber optic interfaces, ATM interfaces, etc.; user equipment can be displays, keyboards, etc.

[0065] Memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0066] The processor can be a general-purpose processor, which can call the real-time clamping force zero-point confirmation program stored in the memory and execute the real-time clamping force zero-point confirmation method provided in the embodiments of this application. For example, the general-purpose processor can be a central processing unit (CPU). The method executed when the real-time clamping force zero-point confirmation program is called can refer to the various embodiments of the real-time clamping force zero-point confirmation method of this application, and will not be repeated here.

[0067] Those skilled in the art will understand that Figure 2 The hardware structure shown does not constitute a limitation of this application and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0068] Fourthly, embodiments of this application also provide a readable storage medium.

[0069] The present application has a real-time clamping force zero-point confirmation program stored on a readable storage medium, wherein when the real-time clamping force zero-point confirmation program is executed by a processor, the steps of the real-time clamping force zero-point confirmation method as described above are implemented.

[0070] The method implemented when the real-time clamping force zero-point confirmation procedure is executed can be referred to in various embodiments of the real-time clamping force zero-point confirmation method of this application, and will not be repeated here.

[0071] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0072] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0073] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0074] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0075] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0076] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0077] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A real-time clamp force zero point confirmation method, characterized by, The real-time clamping force zero point confirmation method comprises: In a preset triggering scenario, a motor of an electromechanical brake actuator is controlled to rotate in a positive clamping direction, the rotation angle and torque of the motor are detected in real time, and a motor rotation angle-torque curve is recorded; A preset calibration torque point is selected on the motor rotation angle-torque curve, a tangent line of the point is obtained, and an intersection of the tangent line and a motor rotation angle coordinate axis is determined; The rotation angle corresponding to the intersection is added with a comprehensive compensation amount to obtain a current clamping force zero point, and the clamping force zero point is updated.

2. The real-time clamping force zero point confirmation method of claim 1, wherein the rotation angle corresponding to the intersection is added with the comprehensive compensation amount to obtain the current clamping force zero point, and the clamping force zero point is updated, comprising: If the preset triggering scenario is a vehicle power-on starting scenario, the rotation angle corresponding to the intersection is added with a comprehensive compensation amount corresponding to an ambient temperature, a brake system efficiency and an initial friction block compression amount to obtain a clamping force zero point of a first brake after the vehicle is powered on, which is used as a reference for subsequent brake cycle zero point updating.

3. The real-time clamping force zero point confirmation method of claim 2, wherein the determination of the initial friction block compression amount comprises: Based on a cumulative driving mileage of the vehicle, a friction block wear amount-driving mileage mapping relationship pre-calibrated through a bench test is combined to calculate a cumulative wear amount of the friction block; The cumulative wear amount of the friction block is deducted from an initial compression amount corresponding to an initial thickness of the friction block to obtain the initial friction block compression amount.

4. The real-time clamping force zero point confirmation method of claim 1, wherein the rotation angle corresponding to the intersection is added with the comprehensive compensation amount to obtain the current clamping force zero point, and the clamping force zero point is updated, comprising: If the preset triggering scenario is a vehicle driving brake scenario, the rotation angle corresponding to the intersection is added with a comprehensive compensation amount corresponding to a real-time ambient temperature, a real-time system rigidity and a current friction block compression amount to calculate a clamping force zero point of a next brake, and a dynamic cycle updating of the clamping force zero point is completed.

5. The real-time clamping force zero point confirmation method of claim 4, wherein the determination of the real-time system rigidity comprises: A real-time temperature of a brake disc is substituted into a temperature-system rigidity mapping relationship pre-calibrated through a bench test to calculate an initial value of the system rigidity at the current temperature; Real-time rotation angle data of a motor in a current brake is combined to correct the initial value of the system rigidity based on a preset system rigidity-motor rotation angle compensation function, and finally a real-time system rigidity adapted to a current working condition is obtained.

6. The real-time clamping force zero point confirmation method of claim 4, wherein the determination of the current friction block compression amount comprises: Based on a cumulative driving mileage of the vehicle, a friction block wear amount-driving mileage mapping relationship pre-calibrated through a bench test is combined to calculate a cumulative wear amount of the friction block; The cumulative wear amount of the friction block, a real-time temperature of a brake disc, and real-time rotation angle data of a motor in a current brake are substituted into a temperature-friction block compression characteristic mapping relationship pre-calibrated through a bench test to calculate a friction block compression amount in a current working condition. ​ ​ ​ ​ ​ 7. The real-time clamping force zero point confirmation method of claim 1, wherein Further comprising the following steps: Based on the confirmed real-time clamping force zero point, in combination with the caliper clamping force stiffness curve pre-written into the system controller, the basic angle at the corresponding position of the stiffness curve is determined according to the target clamping force requested by the system, and then the preset clamping force estimation model is recalled to calculate the temperature compensation angle; Based on the confirmed real-time clamping force zero point, the basic angle and the temperature compensation angle, the total angle that the motor needs to rotate is obtained, and when the motor rotates to the total angle, the output clamping force can match the target clamping force required by the system.

8. A real-time clamp force zero point verification device, characterized by, The real-time clamping force zero point confirmation device comprises: A motor control and data acquisition module, which controls the motor of the electronic mechanical brake actuator to rotate in the positive clamping direction under a preset trigger scenario, and detects and records the motor rotation angle-torque curve in real time; A tangent intersection calculation module, which selects a preset calibration torque point on the motor rotation angle-torque curve, obtains the tangent line of the point and determines the intersection of the tangent line and the motor rotation angle coordinate axis; A zero point compensation updating module, which adds the rotation angle corresponding to the intersection to the integrated compensation amount to obtain the current clamping force zero point, thereby realizing the updating of the clamping force zero point.

9. A real-time clamp force zero confirmation apparatus, characterized by, The real-time clamping force zero point confirmation device comprises a processor, a memory, and a real-time clamping force zero point confirmation program stored on the memory and executable by the processor, wherein when the real-time clamping force zero point confirmation program is executed by the processor, the steps of the real-time clamping force zero point confirmation method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a real-time clamping force zero point confirmation program, wherein when the real-time clamping force zero point confirmation program is executed by the processor, the steps of the real-time clamping force zero point confirmation method according to any one of claims 1 to 7 are implemented.

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