Brake clamping force calculation method, device and storage medium

Abstract

The application provides a clamping force calculation method and device of a brake and a storage medium. The method comprises the following steps: controlling a motor to drive a caliper to approach and clamp a brake disc and to move away from and release the brake disc; collecting a second torque parameter output by the motor and an angle parameter of the motor in the clamping stage and the releasing stage respectively, and calculating corresponding second clamping force parameters according to a transmission ratio; according to the angle parameter and the second clamping force parameter, coefficients in an initial stiffness curve model corresponding to the clamping stage and the releasing stage are respectively solved, and updated stiffness curve models corresponding to the clamping stage and the releasing stage are obtained; wherein the initial stiffness curve model is: a, b, c and d are coefficients, f is the clamping force, and x is the angle of the motor; and the clamping force of the brake is calculated by using the updated stiffness curve model. The method improves the accuracy of calculating the clamping force.

Description

Technical Field

[0001] This application relates to the field of motor control technology, and more specifically, to a method, apparatus and storage medium for calculating the clamping force of a brake. Background Technology

[0002] When controlling an EMB (Electronic Brake) without a clamping force sensor, the clamping force is currently calculated by combining a preset stiffness curve with motor displacement. However, in practical applications, the stiffness curve is affected by factors such as temperature changes and disc wear, leading to inaccurate clamping force estimates based on displacement. Furthermore, due to the inherent hysteresis characteristics of the friction pads, the EMB exhibits different stiffness curves during clamping and release. Using the same stiffness curve to handle the friction force in both cases will further increase the error.

[0003] To address the aforementioned issues, it is clear that EMB requires a method that can automatically identify the stiffness curve throughout its entire lifecycle. However, without a clamping force sensor, calculating the clamping force using motor torque requires an accurate friction force model. Furthermore, friction force itself has time-varying and nonlinear characteristics, making it difficult to accurately model.

[0004] In other words, there is currently no accurate model for calculating the clamping force of the brake, which can produce accurate calculation results. Summary of the Invention

[0005] The purpose of this application is to provide a method, apparatus, and storage medium for calculating the clamping force of a brake. By calculating the clamping force separately for the clamping and release stages using a stiffness curve model without modeling the friction force, the accuracy of the calculation results can be improved.

[0006] In a first aspect, embodiments of this application provide a method for calculating the clamping force of a brake, wherein the brake includes a motor, a caliper, and a brake disc; the method includes: controlling the motor to drive the caliper to approach and clamp the brake disc and to move away from and release the brake disc; during the clamping and releasing phases, respectively acquiring a second torque parameter output by the motor and a rotation angle parameter of the motor, and calculating the corresponding second clamping force parameter according to the transmission ratio; based on the rotation angle parameter and the second clamping force parameter, respectively obtaining the coefficients in the initial stiffness curve model corresponding to the clamping and releasing phases, to obtain the updated stiffness curve model corresponding to the clamping and releasing phases respectively; wherein, the initial stiffness curve model is:

[0007]

[0008] In the formula, a, b, c, and d are the coefficients, f is the clamping force, and x is the rotation angle of the motor; the clamping force of the brake is calculated using the updated stiffness curve model; wherein, the transmission ratio is obtained in advance through the following steps: pre-controlling the motor to drive the caliper to approach and clamp the brake disc and to move away from and release the brake disc; during the pre-clamping and releasing phases, the first torque parameter and the first clamping force parameter output by the motor are collected respectively; and the formula is used to calculate the clamping force. Calculate and record the transmission ratio corresponding to each set of the first torque parameter and the first clamping force parameter; where ν is the transmission ratio, F cl T is the first clamping force parameter. m This refers to the first torque parameter.

[0009] The above-mentioned method for calculating the clamping force of the brake calculates and records the corresponding transmission ratios for both the clamping and releasing stages without modeling the friction force, and calculates the second clamping force parameter based on the second torque parameter. The coefficients in the initial stiffness curve model are then obtained from the second clamping force parameter and the rotation angle parameter to obtain an updated stiffness curve model used to calculate the clamping force for both the clamping and releasing stages. Using this model to calculate the clamping force results in a more accurate calculation.

[0010] In conjunction with the first aspect, optionally, the step of obtaining the coefficients in the initial stiffness curve models corresponding to the clamping stage and the release stage respectively based on the rotation angle parameter and the second clamping force parameter, and obtaining the updated stiffness curve models corresponding to the clamping stage and the release stage respectively, includes: defining an initial guess coefficient vector. The process involves constructing a residual vector, setting an initial damping factor λ0, and constructing a Jacobian matrix; wherein the residual vector and the Jacobian matrix are respectively:

[0011]

[0012]

[0013] In the formula, a0, b0, c0, and d0 are the initial guess coefficients, r i (β) is the residual vector, f i Let ψ be the second clamping force parameter. i Let i be the rotation angle parameter, i = 0, 1, 2…; solve the equation. We obtain Δβ; where λ is the damping factor, I is a 4th order identity matrix, and Δβ = β i -β i-1 ; and by using an iterative formula to iterate and obtain the coefficient vector, the updated stiffness curve model is obtained; wherein, the iterative formula is:

[0014]

[0015] In the formula, β new Let β be the coefficient vector obtained in the current iteration. old This is the coefficient vector obtained from the previous iteration.

[0016] The above-mentioned method for calculating the clamping force of the brake constructs a parameter vector, a residual vector, and a Jacobian matrix based on an initial stiffness curve model, and then derives the equation based on the residual vector and the Jacobian matrix. The parameter vector change Δp is used to calculate the clamping force. Finally, by iterating through this parameter vector change Δβ a certain number of times, more accurate coefficients a, b, c, and d can be obtained, resulting in an updated stiffness curve model for calculating the clamping force. Because the coefficients obtained through this iterative process are more closely approximating to real-world applications compared to methods that directly use the undetermined coefficients method based on multiple sets of collected parameters, the coefficients obtained make the model more closely resemble real-world scenarios, thus further improving the accuracy of clamping force calculations.

[0017] In conjunction with the first aspect, optionally, the step of iterating using an iterative formula to obtain the coefficient vector includes: calculating the current residual corresponding to the coefficient vector obtained in the current iteration and the previous residual corresponding to the coefficient vector obtained in the previous iteration according to the residual calculation formula; wherein, the residual calculation formula is:

[0018]

[0019]

[0020] In the formula, S old S is the current residual. new The previous residual; judgment If the condition is true, decrease λ and continue iterating; if the condition is false, increase λ and continue iterating.

[0021] The above-mentioned method for calculating the clamping force of the brake dynamically increases and decreases the damping factor according to the increase and decrease of the residual, thereby making the coefficients in the stiffness curve model obtained through iteration closer to the actual application scenario, and thus making the clamping force calculated by using the updated stiffness curve model more accurate.

[0022] In conjunction with the first aspect, optionally, the step of iterating using the iterative formula to obtain the coefficient vector further includes: determining... Whether it holds true; where ϵ is the threshold for the change in the sum of squared residuals; if the determination holds true, then the coefficient vector obtained in the current iteration is determined to be converged, and the updated stiffness curve model is obtained based on the coefficient vector obtained in the current iteration.

[0023] The aforementioned method for calculating the clamping force of the brake calculates the change in the sum of squared residuals corresponding to the parameter vector obtained in the current iteration, and determines whether this change in the sum of squared residuals is less than a threshold. If it is less than a threshold, the parameter vector obtained in the current iteration is considered to have converged. The vector elements in this parameter vector can then be used to update the stiffness curve model, thereby obtaining the final updated stiffness curve model. Ultimately, this further improves the accuracy of the clamping force calculation.

[0024] In conjunction with the first aspect, optionally, the step of iterating using the iterative formula to obtain the coefficient vector further includes: determining... Whether it holds true; where δ is the threshold for the change in parameter; if the determination holds true, then the coefficient vector obtained in the current iteration is determined to be converged, and the updated stiffness curve model is obtained based on the coefficient vector obtained in the current iteration.

[0025] The aforementioned method for calculating the clamping force of the brake determines whether the parameter change in the parameter vector obtained in the current iteration is less than a parameter change threshold. If the threshold is less, the parameter vector obtained in the current iteration is considered converged. The vector elements in this parameter vector can then be used as coefficients a, b, c, and d in the updated stiffness curve model, thereby obtaining the final updated stiffness curve model. Ultimately, this further improves the accuracy of the clamping force calculation.

[0026] In conjunction with the first aspect, optionally, the step of iterating using the iterative formula to obtain the coefficient vector further includes: determining whether the number of iterations exceeds the iteration threshold; if it is determined that the iteration threshold is exceeded, then the currently calculated parameter vector is determined to be invalid.

[0027] The above-mentioned method for calculating the clamping force of the brake, if involving too many iterations, usually indicates problems such as unreasonable initial value selection, inadequate convergence condition settings, or insufficient initial damping factor settings. Therefore, limiting the number of iterations can help identify or eliminate these problems, thereby improving the accuracy of the coefficients in the final model. In other words, this further improves the accuracy of the clamping force calculation.

[0028] In conjunction with the first aspect, optionally, in the process of pre-obtaining the transmission ratio, the pre-controlling of the motor to drive the caliper to approach and clamp the brake disc and to move away from and release the brake disc includes: controlling the motor to generate at least four sine waves at specific rotation intervals, where the sine waves represent the functional relationship between the rotation angle of the motor and time; in the process of pre-obtaining the transmission ratio, in the pre-clamping and releasing phases, respectively acquiring the first torque parameter and the first clamping force parameter output by the motor includes: acquiring the first torque parameter and the first clamping force parameter on at least two of the sine waves at the middle position of the at least four sine waves; and calculating the first average torque parameter and the first average clamping force parameter based on the first torque parameter and the first clamping force parameter; the use of formula Calculate and record the transmission ratio corresponding to each set of the first torque parameter and the first clamping force parameter, including: calculating the transmission ratio using the first average torque parameter and the first average clamping force parameter.

[0029] The aforementioned method for calculating the clamping force of the brake involves collecting first torque and first clamping force parameters from at least two sine waves at the intermediate position, and calculating the first average torque and first average clamping force parameters for each sine function. Finally, the transmission ratio is calculated based on these first average torque and first average clamping force parameters. This improves the accuracy of the transmission ratio calculation, thereby improving the accuracy of the calculation of coefficients a, b, c, and d in the initial stiffness curve model. Ultimately, this further improves the accuracy of the clamping force calculation.

[0030] In conjunction with the first aspect, optionally, during the clamping and releasing phases, the step of acquiring the second torque parameter output by the motor and the rotation angle parameter of the motor, respectively, and calculating the corresponding second clamping force parameter based on the transmission ratio, includes: calculating the amplitude of the motor currently operating as a sine function according to the amplitude calculation formula; wherein, the amplitude calculation formula is:

[0031]

[0032] In the formula, A current Let A be the amplitude of the motor currently operating in a sinusoidal function, sinAmpDeclineRate be the amplitude attenuation rate, posStepCnt be the number of times the motor operates in a sinusoidal function at a specific rotation angle, Sat be the saturation function, and sinAmpMax and sinAmpMin be the maximum and minimum amplitude limits for the sinusoidal motion, respectively. The rotation angle parameters of the motor are calculated according to the rotation angle calculation formula, where the rotation angle calculation formula is:

[0033]

[0034] In the formula, ψ(t) is the rotation angle parameter, t is the time the motor operates in a sinusoidal function, and f is the frequency at which the motor operates in a sinusoidal function. posStepValue is the specific rotation angle that the motor rotates at intervals during its sinusoidal operation.

[0035] The above-mentioned method for calculating the clamping force of the brake is to calculate the amplitude of the motor's sinusoidal motion from the average value or center of gravity, and then use this amplitude in combination with the angle calculation formula to calculate the motor's angle parameters. This method is more accurate than directly collecting the motor's angle parameters and does not require additional sensors such as encoders, thus simplifying the calculation of the clamping force.

[0036] In conjunction with the first aspect, optionally, during the process of obtaining the transmission ratio in advance, the step of calculating the first average torque parameter and the first average clamping force parameter based on the first torque parameter and the first clamping force parameter respectively includes: determining whether the first average clamping force parameter exceeds a first clamping force threshold during the clamping stage; if it is determined that it exceeds the first clamping force threshold, controlling the motor to drive the caliper to retract, so as to enter the release stage where the caliper moves away from and releases the brake disc; determining whether the first average clamping force parameter is less than a second clamping force threshold during the release stage; if it is determined that it is less than the second clamping force threshold, ending the acquisition of the first torque parameter and the first clamping force parameter.

[0037] The above-mentioned method for calculating the clamping force of the brake, by excluding the first average clamping force parameter that exceeds the first clamping force threshold during the clamping stage and the first average clamping force parameter that is less than the second clamping force threshold during the release stage, makes the collected parameters closer to the actual application scenario. Furthermore, the coefficients a, b, c, and d obtained by using parameters that approximate the actual application scenario make the updated stiffness curve model closer to the real scenario, thereby further improving the accuracy of the clamping force calculation.

[0038] In conjunction with the first aspect, optionally, during the process of obtaining the transmission ratio in advance, controlling the motor to drive the caliper to retract to enter the release phase where the caliper moves away from and releases the brake disc includes: controlling the motor to drive the caliper forward a specific distance; and controlling the motor to drive the caliper to retract.

[0039] The aforementioned method for calculating the clamping force of the brake avoids interference from hysteresis effects on the collected data by controlling the motor to continue advancing the caliper a specific distance before the motor drives it to retract. This improves the accuracy of calculating coefficients a, b, c, and d from the collected data. Ultimately, this also further improves the accuracy of calculating the clamping force.

[0040] In conjunction with the first aspect, optionally, the step of calculating the clamping force of the brake using the updated stiffness curve model includes: calculating the clamping force during the clamping stage using a first clamping force calculation formula; wherein, the first clamping force calculation formula is:

[0041]

[0042] In the formula, F 1cl F is the clamping force during the clamping phase. R ψ and φ represent rotational speeds less than -n, respectively. threshold The clamping force and motor rotation angle recorded when the clamping phase is switched to the release state, n threshold F is the preset speed threshold. cl,clamping The clamping force is calculated based on the updated stiffness curve model, where k is the attenuation coefficient and ψ is the current rotation angle of the motor; the clamping force during the release phase is calculated using the second clamping force calculation formula; wherein, the second clamping force calculation formula is:

[0043]

[0044] In the formula, F 2cl F is the clamping force during the release phase. R ψ and n represent rotational speeds greater than n, respectively. threshold In the case where the release state is switched to the clamping stage, the clamping force and motor rotation angle recorded, n threshold F is the preset speed threshold. cl,releasing The clamping force is calculated based on the updated stiffness curve model, k is the attenuation coefficient, and ψ is the current rotation angle of the motor.

[0045] The above method for calculating the clamping force of the brake, F R The parameter ψ acts as a "memory parameter" for switching between the clamping and releasing phases. This "memory parameter" corrects the clamping force calculated from the updated stiffness curve model during the clamping and releasing phases, ensuring continuous change in clamping force and avoiding sudden fluctuations. This further improves the accuracy of clamping force calculation.

[0046] Secondly, embodiments of this application also provide a clamping force calculation device for a brake, wherein the brake includes a motor, a caliper, and a brake disc; the device includes: a control module, used to control the motor to drive the caliper to approach and clamp the brake disc and to move away from and release the brake disc; a data acquisition module, used to acquire the second torque parameter output by the motor and the rotation angle parameter of the motor respectively during the clamping and releasing phases, and calculate the corresponding second clamping force parameter according to the transmission ratio; and a calculation module, used to calculate the coefficients in the initial stiffness curve model corresponding to the clamping and releasing phases respectively based on the rotation angle parameter and the second clamping force parameter, to obtain the updated stiffness curve model corresponding to the clamping and releasing phases respectively; wherein the initial stiffness curve model is:

[0047]

[0048] In the formula, a, b, c, and d are the coefficients, f is the clamping force, and x is the rotation angle of the motor; the calculation module is used to calculate the clamping force of the brake using the updated stiffness curve model; wherein, the acquisition module is also used to obtain the transmission ratio in advance through the following steps: pre-controlling the motor to drive the caliper to approach and clamp the brake disc and to move away from and release the brake disc; in the pre-clamping and releasing phases, respectively acquiring the first torque parameter and the first clamping force parameter output by the motor; and using the formula Calculate and record the transmission ratio corresponding to each set of the first torque parameter and the first clamping force parameter; where ν is the transmission ratio, F cl T is the first clamping force parameter. m This refers to the first torque parameter.

[0049] Thirdly, embodiments of this application also provide a storage medium, the storage medium including a computer-readable storage medium on which a computer program is stored, the computer program being executed by a processor to perform the methods described above.

[0050] The aforementioned storage medium has the same beneficial effects as the clamping force calculation method of the brake provided in the first aspect or any alternative embodiment of the first aspect, which will not be elaborated here. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 A flowchart illustrating the method for calculating the clamping force of the brake provided in this application embodiment;

[0053] Figure 2 A flowchart illustrating the method for pre-obtaining the transmission ratio in the brake clamping force calculation method provided in this application embodiment;

[0054] Figure 3 A detailed flowchart of step S130 in the brake clamping force calculation method provided in the embodiments of this application;

[0055] Figure 4 A first specific flowchart of step S133 in the brake clamping force calculation method provided in the embodiments of this application;

[0056] Figure 5 A second specific flowchart of step S133 in the brake clamping force calculation method provided in the embodiments of this application;

[0057] Figure 6 A third specific flowchart of step S133 in the brake clamping force calculation method provided in the embodiments of this application;

[0058] Figure 7 The fourth specific flowchart of step S133 in the brake clamping force calculation method provided in the embodiments of this application;

[0059] Figure 8 A detailed flowchart of step S120 in the brake clamping force calculation method provided in the embodiments of this application;

[0060] Figure 9 A detailed flowchart of step S222 in the brake clamping force calculation method provided in this application embodiment;

[0061] Figure 10 A functional block diagram of the clamping force calculation device for the brake provided in the embodiments of this application. Detailed Implementation

[0062] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this application.

[0064] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0065] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating the method for calculating the clamping force of a brake according to an embodiment of this application. In the method for calculating the clamping force of a brake according to an embodiment of this application, the brake may include a motor, a caliper, and a brake disc.

[0066] The method may include:

[0067] Step S110: Control the motor to drive the caliper to approach and clamp the brake disc and move away from and release the brake disc.

[0068] In step S110 above, the motor can operate in a sinusoidal manner. That is, at certain intervals of motor rotation angle, the motor performs sinusoidal motion, and when the motor rotation angle changes with time in a sinusoidal manner and generates multiple sine waves (e.g., 5), the motor continues to drive the caliper to move, thereby squeezing the brake disc.

[0069] Step S120: During the clamping and releasing phases, the second torque parameter and the motor rotation angle parameter output by the motor are collected respectively, and the corresponding second clamping force parameter is calculated according to the transmission ratio.

[0070] In step S120 above, the clamping stage is when the motor drives the caliper to move towards the brake disc to clamp it. The releasing stage is when the motor drives the caliper to move away from the brake disc to release it. Based on the collected second torque parameter and the motor's rotation angle parameter, combined with the pre-obtained transmission ratio, the corresponding second clamping force parameter can be calculated. Please refer to [link / reference] for details. Figure 2 , Figure 2 This is a flowchart illustrating the method for pre-obtaining the transmission ratio in the brake clamping force calculation method provided in this application embodiment. The specific steps for obtaining the transmission ratio may include:

[0071] Step S210: Pre-control the motor to drive the caliper to approach and clamp the brake disc and to move away from and release the brake disc.

[0072] In step S210 above, the motor can also operate in a sinusoidal manner, that is, in the same way as described in step S110 above.

[0073] Step S220: During the pre-clamping and release phases, the first torque parameter and the first clamping force parameter output by the motor are collected respectively.

[0074] In step S220 above, the pre-clamping stage is the stage of clamping the brake disc during the pre-controllable movement of the motor-driven caliper toward the brake disc. The release stage is the stage of releasing the brake disc during the pre-controllable movement of the motor-driven caliper away from the brake disc.

[0075] Step S230: Using the formula Calculate and record the transmission ratio corresponding to each set of first torque parameters and first clamping force parameters. Where ν is the transmission ratio, F... cl T is the first clamping force parameter. m This is the first torque parameter.

[0076] In step S230 above, ν is the transmission ratio, and F cl T is the first clamping force parameter. m Let be the first torque parameter. The dynamic equations of the EMB are as follows:

[0077]

[0078] Among them, T m Let J be the motor torque, B be the moment of inertia, ω be the motor speed, and T be the torque. Fc For static friction, F cl ν is the clamping force, ν is the transmission ratio, and μ is the coefficient of friction.

[0079] Record the corrected torque ,but:

[0080] Clamping phase:

[0081]

[0082] Release phase:

[0083]

[0084] Observing the equations, we can see that when the motor moves in both forward and reverse directions locally, the magnitudes of the frictional forces are equal and the directions are opposite. After adding them together, the friction terms cancel each other out. Therefore, we can conclude that:

[0085]

[0086] In the formula, T * m,cl T * m,rlThese are the motor torques for the clamping and releasing phases, respectively. If the clamping and releasing operations are designed as sinusoidal periodic motions, friction can be dynamically offset during continuous motion, allowing for real-time estimation of the clamping force. The essence of this method is to utilize the symmetry of friction in reciprocating motion, eliminating systematic friction errors through torque measurements with opposite phases.

[0087] During the clamping and releasing phases, the calculated transmission ratios typically differ to some extent depending on the different first clamping force parameters and corresponding first torque parameters. Therefore, the transmission ratios corresponding to each set of parameters can be recorded in a table for later reference in calculations.

[0088] Step S130: Based on the rotation angle parameter and the second clamping force parameter, calculate the coefficients in the initial stiffness curve model corresponding to the clamping stage and the release stage respectively, and obtain the updated stiffness curve model corresponding to the clamping stage and the release stage respectively.

[0089] In step S130 above, the initial stiffness curve model is:

[0090]

[0091] In the formula, a, b, c, and d are coefficients, f is the clamping force, and x is the motor rotation angle.

[0092] Step S140: Calculate the clamping force of the brake using the updated stiffness curve model.

[0093] In step S140 above, after collecting multiple sets of rotation parameters, the coefficients a, b, c, and d in the initial stiffness curve model can be obtained by combining these parameters, thereby obtaining the final updated stiffness curve model.

[0094] It is worth mentioning that, in this embodiment, steps S110 to S140 are used to calculate the clamping force of the brake. These steps utilize the transmission ratio, which is obtained in advance through steps S210 to S230. That is, it is not necessary to execute steps S210 to S230 each time the clamping force is calculated using the method described in steps S110 to S140. Instead, after obtaining the transmission ratio in advance through steps S210 to S230 once, this transmission ratio can be used. Steps S110 to S140 are executed multiple times to identify the clamping force.

[0095] In the above implementation process, without modeling the friction force, the corresponding transmission ratios are calculated and recorded for both the clamping and releasing stages, and the second clamping force parameter is calculated based on the second torque parameter. The coefficients in the initial stiffness curve model are obtained from the second clamping force parameter and the rotation angle parameter, resulting in an updated stiffness curve model used to calculate the clamping force for both the clamping and releasing stages. Using this model to calculate the clamping force makes the calculated clamping force more accurate.

[0096] Please refer to Figure 3 , Figure 3 This is a flowchart illustrating step S130 in the brake clamping force calculation method provided in this application embodiment. In some optional embodiments, step S130 may include:

[0097] Step S131: Define the initial guess coefficient vector This involves constructing the residual vector, setting the initial damping factor λ0, and constructing the Jacobian matrix.

[0098] In step S131 above, the residual vector and the Jacobian matrix are respectively:

[0099]

[0100]

[0101] In the formula, a0, b0, c0, and d0 are the initial guess coefficients, r i (β) is the residual vector, f i ψ is the second clamping force parameter. i Let i be the angle parameter, i = 0, 1, 2, ...

[0102] Step S132: Solve the equation Thus, Δβ is obtained.

[0103] In step S132 above, λ is the damping factor, I is a 4th order identity matrix, and Δβ=β i -β i-1 In other words, based on the parameter vector, residual vector, and Jacobian matrix constructed from the initial stiffness curve model, Δβ in the above equation can be obtained. Here, since β is a parameter vector, Δβ represents the change in the parameter vector.

[0104] Step S133: Use the iterative formula to iterate and obtain the coefficient vector to get the updated stiffness curve model.

[0105] In step S133 above, the iterative formula is:

[0106]

[0107] In the formula, β new Let β be the coefficient vector obtained in the current iteration. old This is the coefficient vector obtained from the previous iteration. In other words, the iteration can be performed by calculating the change in the parameter vector obtained by solving the equation. After multiple iterations, the final required parameter vector can be obtained, and the vector elements are the coefficients a, b, c, and d in the initial stiffness curve model that need to be obtained.

[0108] In the above implementation process, parameter vectors, residual vectors, and Jacobian matrices are constructed based on the initial stiffness curve model, and equations are obtained based on the residual vectors and Jacobian matrices. The parameter vector change Δp is used to calculate the clamping force. Finally, by iterating through this parameter vector change Δβ a certain number of times, more accurate coefficients a, b, c, and d can be obtained, resulting in an updated stiffness curve model for calculating the clamping force. Because the coefficients obtained through this iterative process are more closely approximating to real-world applications compared to methods that directly use the undetermined coefficients method based on multiple sets of collected parameters, the coefficients obtained make the model more closely resemble real-world scenarios, thus further improving the accuracy of clamping force calculations.

[0109] Please refer to Figure 4 , Figure 4 This is a first specific flowchart of step S133 in the brake clamping force calculation method provided in this application embodiment. In some optional embodiments, step S133 may include:

[0110] Step S1331: Calculate the current residual corresponding to the coefficient vector obtained in the current iteration and the previous residual corresponding to the coefficient vector obtained in the previous iteration according to the residual calculation formula.

[0111] In step S1331 above, the residual calculation formula is:

[0112]

[0113]

[0114] In the formula, S old For the current residual, S new This is the residual from the previous test.

[0115] Step S1332: Determine Whether it is valid or not.

[0116] If the determination is true, then execute step S1333: decrease λ and continue iterating.

[0117] If the determination is not valid, proceed to step S1334: increase λ and continue iterating.

[0118] In steps S1332 to S1334 above, that is, when the residual decreases, the damping factor λ is decreased; when the residual increases, the damping factor λ is increased.

[0119] In the above implementation process, the damping factor is dynamically increased or decreased according to the increase or decrease of the residual, which further makes the coefficients in the stiffness curve model obtained by iteration closer to the actual application scenario, thereby making the clamping force calculated by using the updated stiffness curve model more accurate.

[0120] Please refer to Figure 5 , Figure 5 This is a second specific flowchart of step S133 in the brake clamping force calculation method provided in this application embodiment. In some optional embodiments, step S133 may further include:

[0121] Step S1335: Determine Whether it is valid or not.

[0122] In step S1335 above, ϵ is the threshold for the change in the sum of squared residuals. This threshold can be determined by those skilled in the art based on the convergence degree of the final structure corresponding to the required model accuracy in practical applications.

[0123] If the determination is true, then proceed to step S1336: determine that the coefficient vector obtained in the current iteration has converged, and obtain the updated stiffness curve model based on the coefficient vector obtained in the current iteration.

[0124] In step S1336 above, that is, the change in the sum of squared residuals is calculated based on the parameter vector obtained in the current iteration. If the change in the sum of squared residuals is less than the threshold of the change in the sum of squared residuals, then the parameter vector obtained in the current iteration can be considered to have converged. The process of calculating the coefficients a, b, c, and d through iteration is completed, thereby obtaining the final updated stiffness curve model.

[0125] In the above implementation process, the change in the sum of squared residuals corresponding to the parameter vector obtained in the current iteration is calculated, and it is determined whether this change in the sum of squared residuals is less than a threshold. If it is determined to be less than a threshold, the parameter vector obtained in the current iteration is considered to have converged. The vector elements in this parameter vector can then be used to update the stiffness curve model, thereby obtaining the final updated stiffness curve model. Ultimately, this further improves the accuracy of the clamping force calculation.

[0126] Please refer to Figure 6 , Figure 6This is a third specific flowchart of step S133 in the brake clamping force calculation method provided in this application embodiment. In some optional embodiments, step S133 may further include:

[0127] Step S1337: Determine Whether it is valid or not.

[0128] In step S1337 above, the threshold for the change in the δ parameter is defined. Those skilled in the art can determine this threshold based on the convergence degree of the final structure corresponding to the required model accuracy in practical applications.

[0129] If the determination is true, then proceed to step S1338: determine that the coefficient vector obtained in the current iteration has converged, and obtain the updated stiffness curve model based on the coefficient vector obtained in the current iteration.

[0130] In other words, if the change in the parameter vector obtained in the current iteration is less than the parameter change threshold, it can also be considered that the parameter vector obtained in the current iteration has converged. The process of calculating the coefficients a, b, c, and d through iteration is completed, and the updated stiffness curve model is finally obtained.

[0131] As an optional implementation, combining the previous example regarding the judgment of the change in the residual sum of squares, if either of the following two conditions is met (first, the change in the residual sum of squares is less than a threshold for the change in the residual sum of squares; second, the change in parameters is less than a threshold for the change in parameters), the parameter vector obtained in the current iteration can be considered convergent. Conversely (i.e., neither condition is met), the parameter vector obtained in the current iteration is considered non-convergent, and further iterations can be performed to bring the final parameter vector to converge, thus obtaining the final updated stiffness curve model.

[0132] In the above implementation process, it is determined whether the parameter change of the parameter vector obtained in the current iteration is less than a parameter change threshold. If it is less than the threshold, the parameter vector obtained in the current iteration is considered to have converged. The vector elements in this parameter vector can then be used as coefficients a, b, c, and d in the updated stiffness curve model, thereby obtaining the final updated stiffness curve model. Ultimately, this further improves the accuracy of the clamping force calculation.

[0133] Please refer to Figure 7 , Figure 7 This is the fourth specific flowchart of step S133 in the brake clamping force calculation method provided in this application embodiment. In some optional embodiments, step S133 may further include:

[0134] Step S1339: Determine whether the number of iterations exceeds the iteration threshold.

[0135] If the iteration threshold is exceeded, then step S1330 is executed: the currently calculated parameter vector is determined to be invalid.

[0136] In steps S1338 and S1339 above, that is, in the process of obtaining the coefficients a, b, c, and d in the model, if the number of iterations is too large, the current result can be determined to be invalid. That is, the current calculation of coefficients a, b, c, and d has failed, and the iterative calculation can be restarted.

[0137] In the above implementation process, if the number of iterations is too high, it usually indicates problems such as unreasonable initial value selection, inadequate convergence condition setting, or unreasonable initial damping factor setting. Therefore, by limiting the number of iterations, these problems can be identified or eliminated, thereby improving the accuracy of the coefficients in the final model. That is, this further improves the accuracy of the clamping force calculation.

[0138] As some optional implementations, in the process of obtaining the transmission ratio in advance, step S210 may include:

[0139] Step S211: Control the motor to generate at least 4 sine waves by running a sine function at specific rotation intervals.

[0140] In step S211 above, the sine wave represents the functional relationship between the motor's rotation angle and time. For example, during the process where the motor operates with a sine function for every 100° rotation, it can be controlled to generate 5 sine waves.

[0141] Accordingly, in the process of obtaining the transmission ratio in advance, step S220 may include:

[0142] Step S221: Collect the first torque parameter and the first clamping force parameter on at least two sine waves at the middle position of at least four sine waves.

[0143] In step S221 above, based on the previous example, the first torque parameter and the first clamping force parameter of the middle three sine waves can be selected from the five sine waves.

[0144] Step S222: Calculate the first average torque parameter and the first average clamping force parameter based on the first torque parameter and the first clamping force parameter, respectively.

[0145] In step S222 above, continuing to combine with the previous example, the average value of the first torque parameter and the first clamping force parameter from every 3 sine waves can be calculated to obtain the first average torque parameter and the first average clamping force parameter.

[0146] Accordingly, in the process of obtaining the transmission ratio in advance, step S230 may include:

[0147] Step S231: Calculate the transmission ratio using the first average torque parameter and the first average clamping force parameter.

[0148] In the above implementation process, the first torque parameter and the first clamping force parameter are collected from at least two sine waves at the intermediate position, and the first average torque parameter and the first average clamping force parameter are calculated for each sine function. Finally, the transmission ratio is calculated based on the first average torque parameter and the first average clamping force parameter. This improves the accuracy of the transmission ratio calculation, thereby improving the calculation accuracy of coefficients a, b, c, and d in the initial stiffness curve model. Ultimately, it further improves the accuracy of the clamping force calculation.

[0149] Please refer to Figure 8 , Figure 8 This is a flowchart illustrating step S120 in the brake clamping force calculation method provided in this application embodiment. In some optional embodiments, step S120 may include:

[0150] Step S121: Calculate the amplitude of the motor currently operating as a sine function according to the amplitude calculation formula.

[0151] In step S121 above, the amplitude calculation formula is as follows:

[0152]

[0153] In the formula, A current Here, A represents the amplitude of the motor's current sinusoidal motion, sinAmpDeclineRate is the replication attenuation rate, and posStepCnt is the number of times the motor performs sinusoidal motion at specific rotation intervals. For example, when the motor drives the caliper to squeeze the brake disc, after rotating 100°, it begins sinusoidal motion, at which point posStepCnt = 1; then, after rotating another 100°, it begins sinusoidal motion again, at which point posStepCnt = 2; and so on, thus determining the specific value of posStepCnt. Sat is the saturation function, and sinAmpMax and sinAmpMin are the maximum and minimum amplitude limits for the sinusoidal motion, respectively.

[0154] Step S122: Calculate the motor's rotation angle parameters according to the rotation angle calculation formula.

[0155] In step S122 above, the formula for calculating the angle is:

[0156]

[0157] In the formula, ψ(t) is the rotation angle parameter, t is the time the motor operates in a sinusoidal function, and f is the frequency at which the motor operates in a sinusoidal function. posStepValue is the specific rotation angle that the motor rotates at intervals during its sinusoidal operation, such as 100° in the example described in step S121 above.

[0158] In the above implementation process, the amplitude of the motor's sinusoidal motion is calculated by the amplitude calculation formula, and the motor's rotation angle parameter is calculated by combining the amplitude with the rotation angle calculation formula. This is more accurate than directly collecting the motor's rotation angle parameter, and does not require additional encoders or other sensors, thus simplifying the calculation of clamping force.

[0159] Please refer to Figure 9 , Figure 9 This is a flowchart illustrating the step S222 of the brake clamping force calculation method provided in this application embodiment, where the transmission ratio is obtained in advance. As some optional implementations, step S222 may include the following steps in the process of obtaining the transmission ratio in advance:

[0160] Step S2221: Determine whether the first average clamping force parameter exceeds the first clamping force threshold during the clamping phase.

[0161] In step S2221 above, the first clamping force threshold can be determined based on the maximum clamping force that the caliper can apply to the brake disc during brake application.

[0162] If the clamping force exceeds the first clamping force threshold, then step S2222 is executed: control the motor to drive the caliper to retract, so as to enter the release stage where the caliper moves away from and releases the brake disc.

[0163] In step S2222 above, if the first average clamping force parameter exceeds the first clamping force threshold, it usually indicates that the parameters collected in this stage have exceeded the actual reference situation, and therefore it is unnecessary to collect the parameters in this stage. Furthermore, in conjunction with the previous embodiments, the value of posStepCnt can be reduced by 1 at this time.

[0164] Step S2223: Determine whether the first average clamping force parameter is less than the second clamping force threshold during the release phase.

[0165] In step S2223 above, the clamping force threshold can also be determined based on the minimum clamping force that the caliper can apply to the brake disc during brake application.

[0166] If the force is determined to be less than the second clamping force threshold, then step S2224 is executed: the acquisition of the first torque parameter and the first clamping force parameter is terminated.

[0167] The principle and specific implementation of step S2224 above can be similar to step S2222 above, and will not be repeated here.

[0168] In the above implementation process, by excluding the first average clamping force parameter that exceeds the first clamping force threshold during the clamping stage and the first average clamping force parameter that is less than the second clamping force threshold during the release stage, the collected parameters are made closer to the actual application scenario. The coefficients a, b, c, and d obtained by the parameters that approximate the actual application scenario make the updated stiffness curve model closer to the real scenario, thereby further improving the accuracy of the clamping force calculation.

[0169] In some alternative implementations, step S1222 may include:

[0170] Step S12221: Control the motor to drive the caliper forward a specific distance.

[0171] In step S12221 above, the motor is controlled to drive the caliper forward a specific distance, and the corresponding motor rotation angle can be 90°, 100°, 110°, etc.

[0172] Step S12222: Control the motor to drive the caliper to retract.

[0173] In step S12222 above, that is, before controlling the motor to drive the caliper to retract, the motor can be controlled to drive the caliper to advance an additional distance.

[0174] In the above implementation process, by controlling the motor to drive the caliper to continue advancing a specific distance before the caliper retracts, the interference of hysteresis on the collected data is avoided. This improves the accuracy of calculating coefficients a, b, c, and d from the collected data. Ultimately, this also further improves the accuracy of calculating the clamping force.

[0175] In some alternative implementations, step S140 may include:

[0176] Step S141: Calculate the clamping force during the clamping stage using the first clamping force calculation formula.

[0177] In step S141 above, the formula for calculating the first clamping force is:

[0178]

[0179] In the formula, F 1cl F is the clamping force during the clamping phase. R ψ and φ represent rotational speeds less than -n, respectively. threshold The clamping force and motor rotation angle recorded when the clamping phase is switched to the release state, n threshold F is the preset speed threshold.cl,clamping The clamping force is calculated based on the updated stiffness curve model, k is the attenuation coefficient, and ψ is the current rotation angle of the motor.

[0180] Step S142: Calculate the clamping force during the release phase using the second clamping force calculation formula.

[0181] In step S142 above, the formula for calculating the second clamping force is:

[0182]

[0183] In the formula, F 2cl To release the clamping force during the release phase, F R ψ and n represent rotational speeds greater than n, respectively. threshold The clamping force and motor rotation angle recorded when the release state is switched to the clamping stage, n threshold F is the preset speed threshold. cl,releasing The clamping force is calculated based on the updated stiffness curve model, k is the attenuation coefficient, and ψ is the current rotation angle of the motor.

[0184] In the above implementation process, F R The parameter ψ acts as a "memory parameter" for switching between the clamping and releasing phases. This "memory parameter" corrects the clamping force calculated from the updated stiffness curve model during the clamping and releasing phases, ensuring continuous change in clamping force and avoiding sudden fluctuations. This further improves the accuracy of clamping force calculation.

[0185] Please refer to Figure 10 , Figure 10 This is a functional block diagram of the clamping force calculation device 900 for a brake provided in an embodiment of this application. This application provides a clamping force calculation device 900 for a brake. The brake may include a motor, a caliper, and a brake disc.

[0186] The device may include a control module 910, an acquisition module 920, an acquisition module 930, and a calculation module 940.

[0187] The control module 910 can be used to control the motor to drive the caliper to approach and clamp the brake disc and to move away from and release the brake disc.

[0188] The acquisition module 920 can be used to acquire the second torque parameter and the motor rotation angle parameter output by the motor during the clamping and releasing phases, respectively, and calculate the corresponding second clamping force parameter based on the transmission ratio.

[0189] The calculation module 930 can be used to calculate the coefficients in the initial stiffness curve model corresponding to the clamping stage and the release stage respectively, based on the rotation angle parameter and the second clamping force parameter, to obtain the updated stiffness curve model corresponding to the clamping stage and the release stage respectively. The initial stiffness curve model is as follows:

[0190]

[0191] In the formula, a, b, c, and d are coefficients, f is the clamping force, and x is the motor rotation angle.

[0192] The calculation module 940 can be used to calculate the clamping force of the brake using the updated stiffness curve model.

[0193] The acquisition module 920 is further used to obtain the transmission ratio in advance through the following steps: pre-controlling the motor to drive the caliper to approach and clamp the brake disc and to move away from and release the brake disc; during the pre-clamping and releasing phases, acquiring the first torque parameter and the first clamping force parameter output by the motor, respectively; and using the formula Calculate and record the transmission ratio corresponding to each set of first torque parameters and first clamping force parameters; where ν is the transmission ratio, F cl T is the first clamping force parameter. m This is the first torque parameter.

[0194] As some optional implementations, in the process of obtaining the coefficients in the initial stiffness curve models corresponding to the clamping and release stages based on the rotation angle parameter and the second clamping force parameter, respectively, and obtaining the updated stiffness curve models corresponding to the clamping and release stages, the calculation module 930 can specifically be used to: define the initial guess coefficient vector. The process involves constructing the residual vector, setting the initial damping factor λ0, and constructing the Jacobian matrix. The residual vector and Jacobian matrix are as follows:

[0195]

[0196]

[0197] In the formula, a0, b0, c0, and d0 are the initial guess coefficients, r i (β) is the residual vector, f i ψ is the second clamping force parameter. i Let i be the rotation angle parameter, i = 0, 1, 2, ... Solve the equation. Thus, Δβ is obtained. In the formula, λ is the damping factor, I is a 4th-order identity matrix, and Δβ = β i -β i-1 The iterative formula is used to calculate the coefficient vector and obtain the updated stiffness curve model. The iterative formula is:

[0198]

[0199] In the formula, β new Let β be the coefficient vector obtained in the current iteration. old This is the coefficient vector obtained from the previous iteration.

[0200] As some optional implementation methods, in the process of iterating using the iterative formula to obtain the coefficient vector, the obtaining module 930 can be more specifically used to: calculate the current residual corresponding to the coefficient vector obtained in the current iteration and the previous residual corresponding to the coefficient vector obtained in the previous iteration, according to the residual calculation formula. The residual calculation formula is as follows:

[0201]

[0202]

[0203] In the formula, S old For the current residual, S new This is the residual from the previous iteration. (Judgment) Check if the condition is true. If it is true, decrease λ and continue iterating. If it is false, increase λ and continue iterating.

[0204] As some alternative implementation methods, in the process of iterating using the iterative formula to obtain the coefficient vector, the obtaining module 930 can be more specifically used to: determine Is the condition met? In the formula, ϵ is the threshold for the change in the sum of squared residuals. If the condition is met, the coefficient vector obtained in the current iteration is considered convergent, and the updated stiffness curve model is obtained based on the coefficient vector obtained in the current iteration.

[0205] As some alternative implementation methods, in the process of iterating using the iterative formula to obtain the coefficient vector, the obtaining module 930 can be more specifically used to: determine Is the condition met? In the formula, δ represents the threshold value for the change in the parameter. If the condition is met, the coefficient vector obtained in the current iteration is considered convergent, and the updated stiffness curve model is obtained based on the coefficient vector obtained in the current iteration.

[0206] As one possible implementation, during the iterative process of obtaining the coefficient vector using the iterative formula, it is determined whether the number of iterations exceeds an iteration threshold. If the iteration threshold is exceeded, the currently calculated parameter vector is deemed invalid.

[0207] As some optional implementations, during the process of obtaining the transmission ratio in advance, when the first torque parameter and the first clamping force parameter output by the motor are collected during the pre-clamping and release phases, the acquisition module 920 can specifically be used to: control the motor to generate at least four sine waves at specific intervals of a sine function. Here, the sine wave represents the functional relationship between the motor's rotation angle and time.

[0208] In the process of obtaining the transmission ratio in advance, correspondingly, when the first torque parameter and the first clamping force parameter output by the motor are collected during the pre-clamping and release phases, the acquisition module 920 can specifically be used to: collect the first torque parameter and the first clamping force parameter on at least two sine waves at the middle position of at least four sine waves; and calculate the first average torque parameter and the first average clamping force parameter based on the first torque parameter and the first clamping force parameter, respectively.

[0209] In the process of obtaining the transmission ratio in advance, correspondingly, when using the formula When calculating and recording the transmission ratio corresponding to each set of first torque parameters and first clamping force parameters, the acquisition module 920 can specifically be used to: calculate the transmission ratio using the first average torque parameters and the first average clamping force parameters.

[0210] As some optional implementations, during the clamping and releasing phases, the second torque parameter output by the motor and the rotation angle parameter of the motor are collected respectively, and the corresponding second clamping force parameter is calculated according to the transmission ratio. Specifically, the acquisition module 920 can also be used to: calculate the amplitude of the motor currently operating as a sine function according to the amplitude calculation formula. The amplitude calculation formula is:

[0211]

[0212] In the formula, A current Let A be the amplitude of the motor currently operating in a sinusoidal function, sinAmpDeclineRate be the replication attenuation rate, posStepCnt be the number of times the motor performs a sinusoidal function operation at a specific rotation angle, Sat be the saturation function, and sinAmpMax and sinAmpMin be the maximum and minimum amplitude limits for the sinusoidal motion, respectively. The motor's rotation angle parameters are calculated using the rotation angle calculation formula:

[0213]

[0214] In the formula, ψ(t) is the rotation angle parameter, t is the time the motor operates in a sinusoidal function, and f is the frequency at which the motor operates in a sinusoidal function. posStepValue is the specific rotation angle that the motor rotates at intervals during its sinusoidal operation.

[0215] As some optional implementations, during the process of obtaining the transmission ratio in advance, when calculating the first average torque parameter and the first average clamping force parameter based on the first torque parameter and the first clamping force parameter, respectively, the acquisition module 920 can specifically be used to: determine whether the first average clamping force parameter exceeds a first clamping force threshold during the clamping phase. If it is determined that it exceeds the first clamping force threshold, control the motor to drive the caliper to retract, so as to enter the release phase where the caliper moves away from and releases the brake disc. Determine whether the first average clamping force parameter is less than a second clamping force threshold during the release phase. If it is determined that it is less than the second clamping force threshold, end the acquisition of the first torque parameter and the first clamping force parameter.

[0216] As some optional implementations, during the process of pre-obtaining the gear ratio, when the control motor drives the caliper to retract to enter the release phase where the caliper moves away from and releases the brake disc, the acquisition module 920 can specifically be used to: control the motor to drive the caliper forward a specific distance, and control the motor to drive the caliper to retract.

[0217] As one of the optional implementation methods, in the process of calculating the clamping force of the brake using the updated stiffness curve model, the calculation module 940 can specifically be used to: calculate the clamping force during the clamping stage using a first clamping force calculation formula. The first clamping force calculation formula is:

[0218]

[0219] In the formula, F 1cl F is the clamping force during the clamping phase. R ψ and φ represent rotational speeds less than -n, respectively. threshold The clamping force and motor rotation angle recorded when the clamping phase is switched to the release state, n threshold F is the preset speed threshold. cl,clamping The clamping force is calculated based on the updated stiffness curve model, where k is the attenuation coefficient and ψ is the current rotation angle of the motor. The clamping force during the release phase is calculated using the second clamping force calculation formula. The second clamping force calculation formula is as follows:

[0220]

[0221] In the formula, F 2cl To release the clamping force during the release phase, F R ψ and n represent rotational speeds greater than n, respectively. threshold The clamping force and motor rotation angle recorded when the release state is switched to the clamping stage, n threshold F is the preset speed threshold. cl,releasingThe clamping force is calculated based on the updated stiffness curve model, k is the attenuation coefficient, and ψ is the current rotation angle of the motor.

[0222] It should be understood that this device corresponds to the above-described embodiment of the brake clamping force calculation method and is capable of performing the various steps involved in the above-described method embodiment. The specific functions of this device can be referred to the description above, and detailed descriptions are appropriately omitted here to avoid repetition. This device may include at least one software functional module that can be stored in memory or embedded in the device's operating system (OS) in the form of software or firmware.

[0223] This application also provides a storage medium, which includes a computer-readable storage medium. A computer program is stored on the computer-readable storage medium, and the computer program is executed by a processor to perform the methods described above.

[0224] The computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0225] It should be understood that the disclosed apparatus and methods can also be implemented in other ways, given the several embodiments provided in this application. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, or they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0226] In addition, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0227] The above description is only an optional implementation of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of this application should be covered within the protection scope of the embodiments of this application.

Claims

1. A method for calculating the clamping force of a brake, characterized in that, in, The brake includes a motor, a caliper, and a brake disc; The method includes: The motor is controlled to drive the caliper to approach and clamp the brake disc and to move away from and release the brake disc. During the clamping and releasing phases, the second torque parameter output by the motor and the rotation angle parameter of the motor are collected respectively, and the corresponding second clamping force parameter is calculated according to the transmission ratio. Based on the rotation angle parameter and the second clamping force parameter, the coefficients in the initial stiffness curve models corresponding to the clamping stage and the release stage are calculated respectively, thus obtaining the updated stiffness curve models corresponding to the clamping stage and the release stage respectively; wherein, the initial stiffness curve model is: ； In the formula, a, b, c, and d are the coefficients, f is the clamping force, and x is the rotation angle of the motor; The clamping force of the brake is calculated using the updated stiffness curve model. The transmission ratio is obtained in advance through the following steps: The motor is pre-controlled to drive the caliper to approach and clamp the brake disc and to move away from and release the brake disc. During the pre-clamping and release phases, the first torque parameter and the first clamping force parameter output by the motor are collected respectively; and Using formula Calculate and record the transmission ratio corresponding to each set of the first torque parameter and the first clamping force parameter; where ν is the transmission ratio, F cl T is the first clamping force parameter. m The first torque parameter; The calculation of the clamping force of the brake using the updated stiffness curve model includes: The clamping force during the clamping stage is calculated using the first clamping force calculation formula; wherein, the first clamping force calculation formula is: ； In the formula, F 1cl F is the clamping force during the clamping phase. R ψ and φ represent rotational speeds less than -n, respectively. threshold The clamping force and motor rotation angle recorded when the clamping phase is switched to the release phase, n threshold F is the preset speed threshold. cl,clamping The clamping force is calculated based on the updated stiffness curve model, k is the attenuation coefficient, and ψ is the current rotation angle of the motor during the clamping stage; The clamping force during the release phase is calculated using the second clamping force calculation formula; wherein, the second clamping force calculation formula is: ； In the formula, F 2cl F is the clamping force during the release phase. R ψ and n represent rotational speeds greater than n, respectively. threshold The clamping force and motor rotation angle recorded when the release phase is switched to the clamping phase, n threshold F is the preset speed threshold. cl,releasing The clamping force is calculated based on the updated stiffness curve model, k is the attenuation coefficient, and ψ is the current rotation angle of the motor during the release phase.

2. The method according to claim 1, characterized in that, The step of calculating the coefficients in the initial stiffness curve models corresponding to the clamping and release stages based on the rotation angle parameter and the second clamping force parameter, respectively, to obtain the updated stiffness curve models corresponding to the clamping and release stages, includes: The process involves constructing a residual vector, setting an initial damping factor λ0, and constructing a Jacobian matrix; wherein the residual vector and the Jacobian matrix are respectively: ； In the formula, a0, b0, c0, and d0 are the initial guess coefficients, r i (β) is the residual vector, f i Let ψ be the second clamping force parameter. i Let i be the rotation angle parameter, i = 0, 1, 2, ...; Solve the equation We obtain Δβ; where λ is the damping factor, I is a 4th order identity matrix, and Δβ = β i -β i-1 ;as well as The updated stiffness curve model is obtained by iteratively calculating the coefficient vector using an iterative formula; wherein the iterative formula is: ； In the formula, β new Let β be the coefficient vector obtained in the current iteration. old This is the coefficient vector obtained from the previous iteration.

3. The method according to claim 2, characterized in that, The step of iterating using an iterative formula to obtain the coefficient vector includes: The current residual corresponding to the coefficient vector obtained in the current iteration and the previous residual corresponding to the coefficient vector obtained in the previous iteration are calculated according to the residual calculation formula; wherein, the residual calculation formula is: ； ； In the formula, S old S is the current residual. new The previous residual; judge Is it valid? If the determination is true, then decrease λ and continue iterating; If the determination is not valid, then increase λ and continue iterating.

4. The method according to claim 3, characterized in that, The step of iterating using an iterative formula to obtain the coefficient vector also includes: judge Does this hold true? In the formula, ϵ is the threshold for the change in the sum of squared residuals. If the determination is true, then the coefficient vector obtained in the current iteration is determined to be converged, and the updated stiffness curve model is obtained based on the coefficient vector obtained in the current iteration.

5. The method according to claim 3, characterized in that, The step of iterating using an iterative formula to obtain the coefficient vector also includes: judge Does this hold true? Where δ is the threshold value for the change in the parameter. If the determination is true, then the coefficient vector obtained in the current iteration is determined to be converged, and the updated stiffness curve model is obtained based on the coefficient vector obtained in the current iteration.

6. The method according to claim 3, characterized in that, The step of iterating using an iterative formula to obtain the coefficient vector also includes: Determine if the number of iterations exceeds the iteration threshold; If the iteration threshold is exceeded, the currently calculated parameter vector is deemed invalid.

7. The method according to claim 1, characterized in that, In the process of pre-obtaining the gear ratio, the pre-control of the motor to drive the caliper to approach and clamp the brake disc and to move away from and release the brake disc includes: The motor is controlled to generate at least four sine waves at specific rotation intervals, operating as a sine function; wherein the sine waves represent the functional relationship between the rotation angle of the motor and time. In the process of obtaining the transmission ratio in advance, the first torque parameter and the first clamping force parameter output by the motor are collected in the pre-clamping and release phases, respectively, including: The first torque parameter and the first clamping force parameter are collected from at least two of the middle sine waves in the row of at least four sine waves; and Based on the first torque parameter and the first clamping force parameter, calculate the first average torque parameter and the first average clamping force parameter respectively; The formula used Calculate and record the transmission ratio corresponding to each set of the first torque parameter and the first clamping force parameter, including: The transmission ratio is calculated using the first average torque parameter and the first average clamping force parameter.

8. The method according to claim 7, characterized in that, During the clamping and releasing phases, the second torque parameter output by the motor and the rotation angle parameter of the motor are collected respectively, and the corresponding second clamping force parameter is calculated based on the transmission ratio, including: The amplitude of the motor currently operating as a sine function is calculated according to the amplitude calculation formula; wherein, the amplitude calculation formula is: ； In the formula, A current The amplitude of the motor currently operating in a sinusoidal function is given by A, the reference sine wave amplitude is given by sinAmpDeclineRate, the amplitude decay rate is given by posStepCnt, the number of times the motor currently operates in a sinusoidal function at a specific rotation angle is given by posStepCnt, Sat is the saturation function, and sinAmpMax and sinAmpMin are the maximum and minimum amplitude limits of the sinusoidal motion, respectively. The rotation angle parameters of the motor are calculated according to the rotation angle calculation formula; wherein, the rotation angle calculation formula is: ； In the formula, ψ(t) is the rotation angle parameter, t is the time the motor operates in a sinusoidal function, and f is the frequency at which the motor operates in a sinusoidal function. posStepValue is the specific rotation angle that the motor rotates at intervals during its sinusoidal operation.

9. The method according to claim 7, characterized in that, In the process of obtaining the transmission ratio in advance, the step of calculating the first average torque parameter and the first average clamping force parameter based on the first torque parameter and the first clamping force parameter respectively includes: Determine whether the first average clamping force parameter exceeds the first clamping force threshold during the clamping phase; If the clamping force exceeds the first clamping force threshold, the motor is controlled to drive the caliper to retract, so as to enter the release phase where the caliper moves away from the brake disc and releases it. Determine whether the first average clamping force parameter is less than the second clamping force threshold during the release phase; If the force is determined to be less than the second clamping force threshold, the acquisition of the first torque parameter and the first clamping force parameter is terminated.

10. The method according to claim 9, characterized in that, During the process of obtaining the gear ratio in advance, controlling the motor to drive the caliper to retract, so as to enter the release phase where the caliper moves away from and releases the brake disc, includes: Control the motor to drive the caliper forward a specific distance; and The motor is controlled to drive the caliper to retract.

11. A device for calculating the clamping force of a brake, characterized in that, in, The brake includes a motor, a caliper, and a brake disc; The device includes: The control module is used to control the motor to drive the caliper to approach and clamp the brake disc and to move away from and release the brake disc; The acquisition module is used to acquire the second torque parameter and the rotation angle parameter of the motor output during the clamping and releasing phases, respectively, and calculate the corresponding second clamping force parameter based on the transmission ratio. The calculation module is used to calculate the coefficients in the initial stiffness curve models corresponding to the clamping stage and the release stage respectively, based on the rotation angle parameter and the second clamping force parameter, to obtain the updated stiffness curve models corresponding to the clamping stage and the release stage respectively; wherein, the initial stiffness curve model is: ； In the formula, a, b, c, and d are the coefficients, f is the clamping force, and x is the rotation angle of the motor; The calculation module is used to calculate the clamping force of the brake using the updated stiffness curve model; The acquisition module is further configured to obtain the transmission ratio in advance through the following steps: pre-controlling the motor to drive the caliper to approach and clamp the brake disc and to move away from and release the brake disc; during the pre-clamping and releasing phases, acquiring the first torque parameter and the first clamping force parameter output by the motor, respectively; and using the formula Calculate and record the transmission ratio corresponding to each set of the first torque parameter and the first clamping force parameter; where ν is the transmission ratio, F cl T is the first clamping force parameter. m The first torque parameter; In the process of calculating the clamping force of the brake using the updated stiffness curve model, the calculation module is specifically used for: The clamping force during the clamping stage is calculated using the first clamping force calculation formula; wherein, the first clamping force calculation formula is: ； In the formula, F 1cl F is the clamping force during the clamping phase. R ψ and φ represent rotational speeds less than -n, respectively. threshold The clamping force and motor rotation angle recorded when the clamping phase is switched to the release phase, n threshold F is the preset speed threshold. cl,clamping The clamping force is calculated based on the updated stiffness curve model, k is the attenuation coefficient, and ψ is the current rotation angle of the motor during the clamping stage; The clamping force during the release phase is calculated using the second clamping force calculation formula; wherein, the second clamping force calculation formula is: ； In the formula, F 2cl F is the clamping force during the release phase. R ψ and n represent rotational speeds greater than n, respectively. threshold The clamping force and motor rotation angle recorded when the release phase is switched to the clamping phase, n threshold F is the preset speed threshold. cl,releasing The clamping force is calculated based on the updated stiffness curve model, k is the attenuation coefficient, and ψ is the current rotation angle of the motor during the release phase.

12. A storage medium, characterized in that, The storage medium includes a computer-readable storage medium; the computer-readable storage medium stores a computer program that, when executed by a processor, performs the method as described in any one of claims 1 to 10.

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