Brake contact point identification method, device, electronic brake and storage medium

Abstract

The present application provides a brake contact point identification method, device, electronic brake, and storage medium. The method includes: when the caliper is separated from the brake disc, controlling the motor to drive the caliper to approach and squeeze the brake disc; collecting the current parameters and the motor's rotation angle parameters of the motor; constructing an initial mathematical model between the current flowing through the motor and the motor's rotation angle; using the recursive least squares parameter identification method and the rotation angle parameters to obtain the model coefficients to obtain an updated mathematical model; and calculating the motor's contact disc angle corresponding to the contact point based on the minimum absolute current value corresponding to the stage of increasing absolute value of the current and the updated mathematical model. This method improves the accuracy of mechanical brake contact point identification by using the recursive least squares parameter identification method to obtain the parameters in the constructed mathematical model.

Description

Technical Field

[0001] The present application relates to the field of motor control, and in particular to a brake contact point identification method, device, electronic brake, and storage medium. Background Art

[0002] During electromechanical brake (EMB) operation, accurate identification of the contact point is a key prerequisite for achieving high-precision clearance control. This is primarily due to two reasons: First, a certain dynamic clearance between the friction pad and the brake disc must be maintained during the brake release phase to avoid brake drag caused by residual clamping force. This requires the system to implement active retraction control after accurately calibrating the contact point. Second, for low-cost solutions without a dedicated clamping force sensor, clamping force estimation is based on the contact point position and a pre-calibrated brake system stiffness curve (F=KΔx, where K is the stiffness coefficient and Δx is the displacement across the contact point). The accuracy of this estimation is directly dependent on the contact point detection error.

[0003] Current solutions for identifying contact points primarily rely on motor drive and current signature detection. Specifically, the motor is first controlled in the clamping direction while the motor current is monitored in real time. Then, when the current exceeds a preset fixed threshold (I_threshold) or the current rate of change (di / dt) exceeds a derivative threshold, the contact point is determined.

[0004] However, these solutions fail to account for the temperature-dependent behavior of mechanical resistance torque (e.g., increased resistance torque due to increased viscosity of low-temperature grease and changes in friction coefficient due to expansion of high-temperature materials). Consequently, the threshold setting deviates from the actual contact point over a wide temperature range, leading to detection errors. Furthermore, the current derivative method (di / dt) requires a noise-sensitive first-order differential operation, and even with filtering, phase delay still exists, which can also lead to detection errors.

[0005] In other words, the accuracy of the results of current solutions for contact point identification is not high enough. Summary of the Invention

[0006] The purpose of the embodiments of the present application is to provide a brake contact point identification method, device, electronic brake and storage medium, which uses the recursive least squares parameter identification method to obtain the parameters in the constructed mathematical model, and uses the mathematical model to calculate the motor angle corresponding to the contact point, thereby improving the accuracy of identifying the mechanical brake contact point.

[0007] In a first aspect, an embodiment of the present application provides a brake contact point identification method, wherein the brake includes a motor, a caliper, and a brake disc; the method includes:

[0008] When the caliper is separated from the brake disc, the motor is controlled to drive the caliper to approach and squeeze the brake disc; the current parameters flowing through the motor and the rotation angle parameters of the motor are collected; and an initial mathematical model between the current flowing through the motor and the rotation angle of the motor is constructed; wherein the initial mathematical model is:

[0009] ;

[0010] Where i k is the kth current parameter after the caliper contacts the brake disc, , a1,…,a n are the coefficients of the initial mathematical model, , x k The kth rotation angle parameter after the caliper contacts the brake disc; the model coefficients are obtained by combining the rotation angle parameters using a recursive least squares parameter identification method to obtain an updated mathematical model; and the contact disc angle of the motor corresponding to the contact point is calculated based on the minimum absolute value of the current value corresponding to the stage in which the absolute value of the current increases and the updated mathematical model.

[0011] The above-mentioned brake contact point identification method collects multiple sets of current parameters and angle parameters after the caliper contacts the brake disc, and combines them with the recursive least squares parameter identification method to obtain the parameters in the constructed mathematical model. Finally, the updated mathematical model is used to calculate the motor angle corresponding to the contact point. Compared with the traditional motor drive-current characteristic detection method, the accuracy of identifying the mechanical brake contact point is improved.

[0012] In combination with the first aspect, optionally, the method of obtaining the model coefficients by using a recursive least squares parameter identification method in combination with the rotation angle parameters to obtain an updated mathematical model includes: defining an initial covariance matrix as: Wherein, P0 is the initial covariance matrix, α is a constant, and I is the n-order unit matrix; based on the initial covariance matrix, the gain matrix calculation formula, the updated model parameter calculation formula, and the updated covariance matrix calculation formula are used to iterate and obtain the model coefficients; wherein, the gain matrix calculation formula is:

[0013] ;

[0014] Where K k is the gain matrix calculated in the kth iteration, P k-1 is the updated covariance matrix calculated in the k-1th iteration, λ is the forgetting factor; the updated model parameter calculation formula is:

[0015] ;

[0016] Where θ k is the model coefficient calculated in the kth iteration, θ k-1 The model coefficients calculated in the k-1th iteration; the updated covariance matrix calculation formula is:

[0017] ;

[0018] Where, P k-2 is the updated covariance matrix calculated in the k-2th iteration, K k-1 is the gain matrix calculated in the k-1th iteration, , x k is the k-1th rotation angle parameter after the caliper contacts the brake disc.

[0019] The above-mentioned brake contact point identification method defines an initial covariance matrix and performs multiple iterations by calculating the gain matrix, the covariance matrix and the estimation of the model parameters, and finally calculates the coefficients in the initial mathematical model, thereby obtaining an updated mathematical model, thereby improving the accuracy of the constructed mathematical model between the motor current and the motor rotation angle, and ultimately further improving the accuracy of identifying the mechanical brake contact point.

[0020] In combination with the first aspect, optionally, the collecting group of current parameters and rotation angle parameters flowing through the motor includes: collecting the current parameters and rotation angle parameters in real time; grouping the current parameters with a fixed time length according to the time corresponding to the current parameters; and calculating the average current parameter of all the current parameters in each group; wherein, i k is the average current parameter of the kth group.

[0021] The above-mentioned brake contact point identification method, by grouping the collected current parameters at intervals of specific time length, calculating the average current parameters of the current parameters in each group, and finally using them to obtain the coefficients in the initial mathematical model, also improves the accuracy of the constructed mathematical model between the motor current and the motor's rotation angle, and ultimately further improves the accuracy of identifying the mechanical brake contact point.

[0022] In combination with the first aspect, optionally, calculating the contact disk angle of the motor corresponding to the contact point based on the minimum absolute value of the current corresponding to the stage in which the absolute value of the current increases and the updated mathematical model includes: determining whether the current parameter satisfies both a first condition and a second condition; wherein the first condition is:

[0023] ;

[0024] The second condition is:

[0025] ;

[0026] Where i is the current parameter, RLS_Threshold1 is the dynamic trigger threshold, i fitted is the fitting current parameter calculated based on the current parameter and the updated mathematical model, and RLS_Threshold2 is the residual tolerance threshold; if it is determined that the first condition and the second condition are met at the same time, RLS_Threshold3 is used as the current parameter in the updated mathematical model to calculate the contact disc angle of the motor corresponding to the contact point; wherein RLS_Threshold3 is the third current threshold.

[0027] This brake contact point identification method determines whether both the dynamic trigger threshold and the residual tolerance threshold conditions are met. If these conditions are met, the third current threshold is used as the effective contact disc current value. This is then used in conjunction with an updated mathematical model to calculate the motor contact disc angle. This eliminates the interference of abnormal data on the calculation results and improves the robustness of the contact disc angle calculation. Ultimately, this method further enhances the accuracy of mechanical brake contact point identification.

[0028] In combination with the first aspect, optionally, RLS_Threshold3 is used as the current parameter in the updated mathematical model to calculate the contact disk angle of the motor corresponding to the contact point, including: judging whether the minimum value of the average value of the absolute current currently calculated is less than the minimum value of the average value of the absolute current calculated last time; if it is judged to be not less than, it is regarded as a current rise, and the number of consecutive rises is recorded; judging whether the number of consecutive rises exceeds a number threshold; if it is judged to exceed, the average value of the motor angle calculated by RLS_Threshold3 is used as the contact disk angle.

[0029] The above-mentioned brake contact point identification method, by successively comparing the calculated average current values, determines that the calculated current average value is in a continuous upward trend, and when the number of increases exceeds a threshold number, uses the third current threshold as the current value for calculating the contact disc angle, thereby further improving the accuracy of calculating the contact disc angle, thereby further improving the accuracy of identifying the mechanical brake contact point.

[0030] In combination with the first aspect, optionally, using RLS_Threshold3 as the current parameter in the updated mathematical model to calculate the contact disk angle of the motor corresponding to the contact point further includes: if it is determined to be less than , calculating the contact disk angle of the motor corresponding to the contact point using an updated third current threshold; wherein the updated third current threshold is calculated according to the following formula:

[0031] ;

[0032] Wherein, RLS_Threshold3 is the third current threshold, I avg_current The minimum value of the average value of the absolute current calculated at present, I0 is a constant.

[0033] In the above brake contact point identification method, if the currently calculated current value is less than the immediately preceding calculated current value, indicating a decrease in current value, the third current threshold is updated by adding a constant current value to the currently calculated current value, which serves as the current value used to calculate the contact disc angle. This makes the brake contact point identification method provided in this embodiment of the application more flexible and applicable, thereby improving the accuracy of mechanical brake contact point identification.

[0034] In combination with the first aspect, optionally, calculating the contact plate angle of the motor corresponding to the contact point using the third current threshold includes: calculating the contact plate angle using the third current threshold; and clearing the recorded number of consecutive rises and the corresponding calculated average value of the motor angle.

[0035] The above brake contact point identification method resets the current rise times recorded in the buffer to zero based on the contact disc angle calculated using the third current threshold when the current drops, facilitating subsequent re-recording from zero. This further improves the accuracy of contact disc current determination and, consequently, the precision of mechanical brake contact point identification.

[0036] In a second aspect, an embodiment of the present application further provides a brake contact point identification device, wherein the brake includes a motor, a caliper, and a brake disc; the device includes: a control module for controlling the motor to drive the caliper to approach and squeeze the brake disc when the caliper is separated from the brake disc; a collection module for collecting current parameters flowing through the motor and rotation angle parameters of the motor; and a construction module for constructing an initial mathematical model between the current flowing through the motor and the rotation angle of the motor; wherein the initial mathematical model is:

[0037] ;

[0038] Where i k is the kth current parameter after the caliper contacts the brake disc, , a1…a n are the coefficients of the initial mathematical model, , x kis the kth rotation angle parameter after the caliper contacts the brake disc; an obtaining module is used to obtain the model coefficients by using a recursive least squares parameter identification method in combination with the rotation angle parameters to obtain an updated mathematical model; a calculation module is used to calculate the contact disc angle of the motor corresponding to the contact point based on the minimum absolute value of the current value corresponding to the stage of increasing absolute value of the current and the updated mathematical model.

[0039] The above-mentioned brake contact point identification device has the same beneficial effects as the brake contact point identification method provided by the above-mentioned first aspect or any optional implementation manner of the first aspect, and will not be described in detail here.

[0040] In a third aspect, an embodiment of the present application further provides an electronic brake, comprising: a brake and a controller; the controller is electrically connected to the brake; and the controller is used to control the brake according to the method described in the first aspect.

[0041] The above-mentioned electronic brake has the same beneficial effects as the brake contact point identification method provided in the above-mentioned first aspect, or any optional implementation manner of the first aspect, and will not be described in detail here.

[0042] In a fourth aspect, an embodiment of the present application further provides a storage medium, which includes a computer-readable storage medium, on which a computer program is stored, and the computer program executes the method described above when executed by a processor.

[0043] The above-mentioned storage medium has the same beneficial effects as the brake contact point identification method provided by the above-mentioned first aspect, or any optional implementation manner of the first aspect, and is not described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0045] Figure 1 A flow chart of a brake contact point identification method provided in an embodiment of the present application;

[0046] Figure 2 This is a specific flow chart of step S170 in the brake contact point identification method provided in an embodiment of the present application;

[0047] Figure 3A specific flow chart of step S130 in the brake contact point identification method provided in an embodiment of the present application;

[0048] Figure 4 A specific flow chart of step S190 in the brake contact point identification method provided in an embodiment of the present application;

[0049] Figure 5 A specific flow chart of step S192 in the brake contact point identification method provided in an embodiment of the present application;

[0050] Figure 6 This is a specific flow chart of step S1925 in the brake contact point identification method provided in an embodiment of the present application;

[0051] Figure 7 This is a functional module diagram of the brake contact point identification device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0052] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0054] In the description of the embodiments of this application, the technical terms "first," "second," etc. are used only to distinguish different objects and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise specifically defined.

[0055] See Figure 1 , Figure 1 Flowchart of the brake contact point identification method provided by the embodiment of the present application. In the brake contact point identification method provided by the embodiment of the present application, the brake may include a motor, a caliper, and a brake disc.

[0056] The method may include:

[0057] Step S110: When the caliper is separated from the brake disc, the motor is controlled to drive the caliper to approach and squeeze the brake disc.

[0058] In step S110, the motor may be controlled to retract the caliper to separate the caliper from the brake disc. For example, the motor may be controlled to rotate 2500 degrees in the direction of retraction. Subsequently, the motor may be controlled to drive the caliper closer to and squeeze the brake disc. While the caliper is in contact with and squeezing the brake disc, the motor may operate at a constant speed to drive the caliper.

[0059] Step S130: collecting parameters of the current flowing through the motor and the rotation angle parameters of the motor.

[0060] In step S130, there is typically a functional relationship between the motor current and the caliper displacement. The caliper displacement is primarily determined by the motor's rotational angle and the linkage between the caliper and motor (i.e., the transmission ratio). Therefore, the specific functional relationship can typically be determined using the current parameters and the motor's rotational angle parameters.

[0061] Step S150: constructing an initial mathematical model between the current flowing through the motor and the rotation angle of the motor.

[0062] In the above step S150, the initial mathematical model is:

[0063] ;

[0064] Where i k is the kth current parameter after the caliper contacts the brake disc, , a1,…,a n are the coefficients of the initial mathematical model, x k is the kth rotation angle parameter after the caliper contacts the brake disc.

[0065] For example, when n=4, the above mathematical model becomes , which means that the mathematical model is a cubic function. When n=3, the above mathematical model becomes , that is, the mathematical model is a cubic function. Regarding the specific value of n, those skilled in the art can determine it by themselves according to the specific circumstances of actual application.

[0066] Step S170: Utilizing the recursive least squares parameter identification method and combining the rotation angle parameters to obtain the model coefficients, thereby obtaining an updated mathematical model.

[0067] In the above step S170, the coefficients 1, ..., a in the above initial mathematical model can be obtained based on the collected multiple sets of current parameters and rotation angle parameters and combined with the recursive least squares parameter identification method. n , and obtain the final updated mathematical model.

[0068] Step S190: Calculating the contact plate rotation angle of the motor corresponding to the contact point according to the minimum absolute value of the current corresponding to the stage of increasing absolute value of the current and the updated mathematical model.

[0069] In step S190, after the caliper contacts the brake disc, the absolute value of the current flowing through the motor typically increases as the motor continues to drive the caliper to squeeze the brake disc. Therefore, the current at the initial moment of this increasing trend can be considered the current at the point of contact between the caliper and the brake disc, i.e., the current corresponding to the contact point. This current, combined with the updated mathematical model obtained previously, can be used to calculate the motor rotation angle corresponding to the contact point, i.e., the contact disc angle.

[0070] During the above implementation process, multiple sets of current parameters and angle parameters are collected after the caliper contacts the brake disc, and the parameters in the constructed mathematical model are obtained by combining the recursive least squares parameter identification method. Finally, the updated mathematical model is used to calculate the motor angle corresponding to the contact point. Compared with the traditional motor drive-current characteristic detection method, the accuracy of identifying the mechanical brake contact point is improved.

[0071] Please refer to Figure 2 , Figure 2 This is a specific flow chart of step S170 in the brake contact point identification method provided in an embodiment of the present application. In some optional implementations, step S170 may include:

[0072] Step S171: define the initial covariance matrix as: Where P0 is the initial covariance matrix, α is a constant, and I is the n-order unit matrix.

[0073] In the above step S171, for example, the value of α can be 10 4 , combined with the example described above, when n=3, the mathematical model becomes , then I can also be a 3-order unit matrix, that is, .

[0074] Step S172: Based on the initial covariance matrix, the gain matrix calculation formula, the updated model parameter calculation formula, and the updated covariance matrix calculation formula are used to iterate and obtain the model coefficients.

[0075] In the above step S172, the gain matrix calculation formula is:

[0076] ;

[0077] Where K k is the gain matrix calculated in the kth iteration, P k-1is the updated covariance matrix calculated in the k-1th iteration, and λ is the forgetting factor.

[0078] The calculation formula for updating model parameters is:

[0079] ;

[0080] Where θ k is the model coefficient calculated in the kth iteration, θ k-1 The model coefficients calculated in the k-1th iteration.

[0081] The updated covariance matrix calculation formula is:

[0082] ;

[0083] Where, P k-2 is the updated covariance matrix calculated in the k-2th iteration, K k-1 is the gain matrix calculated in the k-1th iteration, , x k is the k-1th rotation angle parameter after the caliper contacts the brake disc.

[0084] That is to say, in the initial mathematical model, coefficient is sought and needs to be sought to obtain the gain matrix, and the gain matrix in the current iterative process needs the covariance matrix sought in the adjacent last iteration, and the seeking of the covariance matrix in the last iterative process needs the covariance matrix sought in the last iterative process and the gain matrix in the last iterative process. Therefore, the relationship of such circulation just needs to be through the iteration of corresponding number of times, just can seek the coefficient in the initial mathematical model. Concrete number of iterations, those skilled in the art can determine according to the actual demand to model accuracy, in the present application embodiment, do not do specific restriction to this.

[0085] In the above implementation process, by defining the initial covariance matrix and performing multiple iterations by calculating the gain matrix, the covariance matrix and the estimation of the model parameters, the coefficients in the initial mathematical model are finally calculated, thereby obtaining an updated mathematical model, thereby improving the accuracy of the constructed mathematical model between the motor current and the motor rotation angle, and ultimately further improving the accuracy of identifying the mechanical brake contact point.

[0086] Please refer to Figure 3 , Figure 3 This is a specific flow chart of step S130 in the brake contact point identification method provided in an embodiment of the present application. In some optional implementations, step S130 may include:

[0087] Step S131: collecting current parameters and rotation angle parameters in real time.

[0088] Step S132: grouping the current parameters with fixed durations according to the moments corresponding to the current parameters.

[0089] Step S133: Calculate the average current parameter of all current parameters in each group.

[0090] In the above steps S131 to S133, for example, the collected current parameters and angle parameters are used as a reference, and the current parameters and angle parameters corresponding to each 10ms are grouped as a set of parameters, and the average current parameter in each set of parameters is calculated. k is the average current parameter of the kth group.

[0091] In the above implementation process, the collected current parameters are grouped at intervals of specific time, and the average current parameters in each group are calculated, and finally used to obtain the coefficients in the initial mathematical model. This also improves the accuracy of the constructed mathematical model between the motor current and the motor's rotation angle, and ultimately further improves the accuracy of identifying the mechanical brake contact point.

[0092] Please refer to Figure 4 , Figure 4 This is a specific flow chart of step S190 in the brake contact point identification method provided in an embodiment of the present application. In some optional implementations, step S190 may include:

[0093] Step S191: Determine whether the current parameter satisfies both the first condition and the second condition.

[0094] In the above step S191, the first condition is:

[0095] ;

[0096] The second condition is:

[0097] ;

[0098] Where i is the current parameter, RLS_Threshold1 is the dynamic trigger threshold, i fitted The RLS_Threshold2 is the residual tolerance threshold, which can be set to 2-3 times the noise peak value in the collected current data. For example, if the noise peak value is 0.2A, the residual tolerance threshold can be specifically determined to be 0.5A.

[0099] If it is determined that both the first condition and the second condition are satisfied, step S192 is executed: using RLS_Threshold3 as the current parameter in the updated mathematical model, the contact plate rotation angle of the motor corresponding to the contact point is calculated.

[0100] In step S192, RLS_Threshold3 is the third current threshold. That is, in this embodiment of the present application, the third current threshold used to calculate the touchpad angle is valid only when both the dynamic trigger threshold and the residual tolerance threshold conditions are met. This current value can then be substituted into the updated mathematical model to calculate the touchpad angle of the motor corresponding to the contact point.

[0101] In this implementation, the system determines whether both the dynamic trigger threshold and the residual tolerance threshold conditions are met. If both conditions are met, the third current threshold is used as the effective contact disc current value. This value is then used in conjunction with the updated mathematical model to calculate the motor contact disc angle. This eliminates the impact of abnormal data on the calculation results and improves the robustness of the contact disc angle calculation. Ultimately, this further enhances the accuracy of mechanical brake contact point identification.

[0102] Please refer to Figure 5 , Figure 5 This is a specific flow chart of step S192 in the brake contact point identification method provided in an embodiment of the present application. In some optional implementations, step S192 may include:

[0103] Step S1921: Determine whether the minimum value of the average value of the absolute current currently calculated is smaller than the minimum value of the average value of the absolute current calculated last time.

[0104] If it is determined to be not less than, step S1922 is executed: the current is regarded as rising, and the number of consecutive rises is recorded.

[0105] Step S1923: Determine whether the number of consecutive increases exceeds a threshold.

[0106] If it is determined to be exceeded, step S1924 is executed: the average value of the motor rotation angle calculated by RLS_Threshold3 is used as the touch plate rotation angle.

[0107] In the above steps S1921 to S1924, that is, when the number of times the absolute value of the current rises exceeds the threshold, the average current is calculated based on the current in the rising stage, and the average current is used as the current value for calculating the touch plate rotation angle.

[0108] In the above implementation process, by comparing the calculated average current values ​​one by one, it is determined that the calculated current average value is in a continuous upward trend, and when the number of increases exceeds the number threshold, the third current threshold is used as the current value for calculating the touch disc angle, thereby further improving the accuracy of calculating the touch disc angle, thereby further improving the accuracy of identifying the mechanical brake contact point.

[0109] Please continue to refer to Figure 5 In some optional implementations, step S192 may further include:

[0110] If it is determined to be less than, step S1925 is executed: the contact plate angle of the motor corresponding to the contact point is calculated using the updated third current threshold.

[0111] In the above step S1925, the updated third current threshold is calculated according to the following formula:

[0112] ;

[0113] Where RLS_Threshold3 is the third current threshold, I avg_current The minimum value of the average value of the absolute current calculated at present, I0 is a constant, for example: 1.5A.

[0114] In the above implementation, if the currently calculated current value is less than the immediately preceding calculated current value, indicating a decrease in current value, the third current threshold is updated by adding a constant current value to the currently calculated current value, which serves as the current value used to calculate the contact disc angle. This makes the brake contact point identification method provided in this embodiment of the application more flexible and applicable, thereby improving the accuracy of mechanical brake contact point identification.

[0115] Please refer to Figure 6 , Figure 6 This is a specific flow chart of step S1925 in the brake contact point identification method provided in an embodiment of the present application. In some optional implementations, step S1925 may include:

[0116] Step S19251: Calculate the touch panel angle using the third current threshold.

[0117] Step S19252: Clear the recorded number of consecutive rises and the corresponding calculated average value of the motor rotation angle.

[0118] In the above steps, that is, each time the current average value is calculated, if the current is in the rising stage, a record indicating that the current has risen once can be recorded in the buffer area. If the current drops, the previously recorded number of current rises is cleared so that the subsequent record can be restarted from 0.

[0119] In the above implementation, when the current decreases, the number of current increases recorded in the buffer is cleared to zero based on the calculation of the contact plate angle using the third current threshold. This facilitates subsequent re-recording from 0. This further improves the accuracy of determining the contact plate current, and accordingly improves the accuracy of identifying the mechanical brake contact point.

[0120] See Figure 7 , Figure 7 : is a functional module diagram of a brake contact point identification device 700 provided in an embodiment of the present application. Based on the same concept, the present application provides a brake contact point identification device 700. The brake may include a motor, a caliper, and a brake disc.

[0121] The brake contact point identification device 700 may include a control module 710 , a collection module 720 , a construction module 730 , a determination module 740 , and a calculation module 750 .

[0122] The control module 710 can be used to control the motor to drive the caliper to approach and squeeze the brake disc when the caliper is separated from the brake disc.

[0123] The acquisition module 720 may be used to acquire the current parameters flowing through the motor and the rotation angle parameters of the motor.

[0124] The construction module 730 can be used to construct an initial mathematical model between the current flowing through the motor and the rotation angle of the motor. The initial mathematical model is:

[0125] ;

[0126] Where i k is the kth current parameter after the caliper contacts the brake disc, , a1…a n are the coefficients of the initial mathematical model, , x k is the kth rotation angle parameter after the caliper contacts the brake disc.

[0127] The obtaining module 740 can be used to obtain model coefficients by using a recursive least squares parameter identification method in combination with the rotation angle parameters to obtain an updated mathematical model.

[0128] The calculation module 750 can be used to calculate the contact plate angle of the motor corresponding to the contact point according to the minimum absolute value of the current corresponding to the stage of increasing absolute value of the current and the updated mathematical model.

[0129] As some optional implementations, in the process of obtaining the model coefficients by using the recursive least squares parameter identification method in combination with the rotation angle parameters to obtain the updated mathematical model, the obtaining module 740 can be specifically used to define the initial covariance matrix as: Where P0 is the initial covariance matrix, α is a constant, and I is the n-order unit matrix.

[0130] Based on the initial covariance matrix, the gain matrix calculation formula, the updated model parameter calculation formula, and the updated covariance matrix calculation formula are used to iterate and obtain the model coefficients. Among them, the gain matrix calculation formula is:

[0131] ;

[0132] Where K k is the gain matrix calculated in the kth iteration, P k-1 is the updated covariance matrix calculated in the k-1th iteration, and λ is the forgetting factor.

[0133] The calculation formula for updating model parameters is:

[0134] ;

[0135] Where θ k is the model coefficient calculated in the kth iteration, θ k-1 The model coefficients calculated in the k-1th iteration.

[0136] The updated covariance matrix calculation formula is:

[0137] ;

[0138] Where, P k-2 is the updated covariance matrix calculated in the k-2th iteration, K k-1 is the gain matrix calculated in the k-1th iteration, , x k is the k-1th rotation angle parameter after the caliper contacts the brake disc.

[0139] As some optional implementations, in the process of collecting the current parameters and the rotation angle parameters of the motor, the collection module 720 can be specifically used to: collect the current parameters and the rotation angle parameters in real time; group the current parameters with a fixed time length according to the time corresponding to the current parameters; and calculate the average current parameter of all current parameters in each group. k is the average current parameter of the kth group.

[0140] As some optional implementations, in the process of calculating the contact angle of the motor corresponding to the contact point based on the minimum absolute value of the current corresponding to the stage of increasing absolute value of the current and updating the mathematical model, the calculation module 750 can be specifically used to: determine whether the current parameter satisfies both the first condition and the second condition. The first condition is:

[0141] ;

[0142] The second condition is:

[0143] ;

[0144] Where i is the current parameter, RLS_Threshold1 is the dynamic trigger threshold, i fitted is the fitted current parameter calculated based on the current parameter and the updated mathematical model, and RLS_Threshold2 is the residual tolerance threshold.

[0145] If it is determined that both the first and second conditions are met, RLS_Threshold3 is used as the current parameter in the updated mathematical model to calculate the contact disc angle of the motor corresponding to the contact point; wherein RLS_Threshold3 is the third current threshold.

[0146] As some optional implementations, in the process of using RLS_Threshold3 as the current parameter in the updated mathematical model to calculate the contact disk angle of the motor corresponding to the contact point, the calculation module 750 can be specifically used to: determine whether the minimum value of the average value of the absolute current currently calculated is less than the minimum value of the average value of the absolute current calculated last time; if it is determined to be not less than, it is regarded as a current rise, and the number of consecutive rises is recorded; determine whether the number of consecutive rises exceeds the number threshold; if it is determined to exceed, the average value of the motor angle calculated by RLS_Threshold3 is used as the contact disk angle.

[0147] As some optional implementations, when using RLS_Threshold3 as the current parameter in the updated mathematical model to calculate the contact plate rotation angle of the motor corresponding to the contact point, the calculation module 750 can also be specifically configured to: if it is determined to be less than , calculate the contact plate rotation angle of the motor corresponding to the contact point using the updated third current threshold. The updated third current threshold is calculated according to the following formula:

[0148] ;

[0149] Where RLS_Threshold3 is the third current threshold, I avg_current is the average value currently calculated, and I0 is a constant.

[0150] As some optional implementations, in the process of calculating the contact disk rotation angle of the motor corresponding to the contact point using the third current threshold, the calculation module 750 may be more specifically configured to: calculate the contact disk rotation angle using the third current threshold, and reset the recorded number of consecutive rise times and the corresponding calculated average value of the motor rotation angle to zero.

[0151] It should be understood that this device corresponds to the aforementioned brake contact point identification method embodiment and is capable of executing each of the steps involved in the aforementioned method embodiment. The specific functions of this device can be found in the description above; to avoid repetition, a detailed description is omitted here. The device includes at least one software functional module that can be stored in a memory in the form of software or firmware or embedded in the device's operating system (OS).

[0152] Based on the same concept, an embodiment of the present application provides an electronic brake, comprising: a brake and a controller, wherein the controller is electrically connected to the brake;

[0153] The controller is used to control the brake according to the brake contact point identification method described above.

[0154] The present application also provides a storage medium including a computer-readable storage medium having a computer program stored thereon, which executes the above method when executed by a processor.

[0155] Among them, 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 read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0156] In the several embodiments provided in the embodiments of the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions, and operations of the devices, methods, and computer program products according to the multiple embodiments of the embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment, or a portion of code, and the module, program segment, or a portion of code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the boxes can also occur in a different order than the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0157] In addition, the functional modules in each embodiment of the present 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.

[0158] The above description is only an optional implementation method of the embodiment of the present application, but the protection scope of the embodiment of the present application is not limited to this. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in the embodiment of the present application, and they should all be covered by the protection scope of the embodiment of the present application.

Claims

1. A brake contact point identification method, characterized in that: in, The brake comprises a motor, a caliper and a brake disc; The method comprises: When the caliper is separated from the brake disc, the motor is controlled to drive the caliper to approach and squeeze the brake disc; collecting current parameters flowing through the motor and rotation angle parameters of the motor; An initial mathematical model between the current flowing through the motor and the rotation angle of the motor is constructed; wherein the initial mathematical model is: ； Where i k is the kth current parameter after the caliper contacts the brake disc, , a1,…,a n are the coefficients of the initial mathematical model, , x k is the kth rotation angle parameter after the caliper contacts the brake disc; Utilizing a recursive least squares parameter identification method and combining the rotation angle parameters to obtain the model coefficients, thereby obtaining an updated mathematical model; and Calculating a contact disc rotation angle of the motor corresponding to the contact point according to a minimum absolute value of the current corresponding to a stage in which the absolute value of the current increases and the updated mathematical model; The step of calculating the contact plate rotation angle of the motor corresponding to the contact point according to the minimum absolute value of the current corresponding to the stage in which the absolute value of the current increases and the updated mathematical model includes: Determine whether the current parameter satisfies both a first condition and a second condition; wherein the first condition is: ； The second condition is: ； Where i is the current parameter, RLS_Threshold1 is the dynamic trigger threshold, i fitted is the fitted current parameter calculated based on the current parameter and the updated mathematical model, RLS_Threshold2 is the residual tolerance threshold; If it is determined that both the first and second conditions are met, RLS_Threshold3 is used as the current parameter in the updated mathematical model to calculate the contact disc angle of the motor corresponding to the contact point; wherein RLS_Threshold3 is a third current threshold; the third current threshold is calculated according to the following formula: ； Wherein, RLS_Threshold3 is the third current threshold, I avg_current The minimum value of the average value of the absolute current calculated at present, I0 is a constant.

2. The method according to claim 1, characterized in that The method of using the recursive least squares parameter identification method in combination with the rotation angle parameter to obtain the model coefficients to obtain an updated mathematical model includes: The initial covariance matrix is ​​defined as: ; Where P0 is the initial covariance matrix, α is a constant, and I is the n-order unit matrix; Based on the initial covariance matrix, the gain matrix calculation formula, the updated model parameter calculation formula, and the updated covariance matrix calculation formula are used to iterate and obtain the model coefficients; wherein the gain matrix calculation formula is: ； Where K k is the gain matrix calculated in the kth iteration, P k-1 is the updated covariance matrix calculated in the k-1th iteration, and λ is the forgetting factor; The calculation formula for updating the model parameters is: ； Where θ k is the model coefficient calculated in the kth iteration, θ k-1 The model coefficients calculated in the k-1th iteration; The updated covariance matrix calculation formula is: ； Where, P k-2 is the updated covariance matrix calculated in the k-2th iteration, K k-1 is the gain matrix calculated in the k-1th iteration, , x k is the k-1th rotation angle parameter after the caliper contacts the brake disc.

3. The method according to claim 1, characterized in that The acquisition group collects current parameters flowing through the motor and rotation angle parameters of the motor, including: collecting the current parameters and the rotation angle parameters in real time; Grouping the current parameters with a fixed duration according to the moments corresponding to the current parameters; and calculating an average current parameter of all said current parameters in each group; Among them, i k is the average current parameter of the kth group.

4. The method according to claim 1, wherein The method of using RLS_Threshold3 as the current parameter in the updated mathematical model to calculate the contact disc angle of the motor corresponding to the contact point includes: Determine whether the minimum value of the average value of the absolute current currently calculated is less than the minimum value of the average value of the absolute current calculated last time; If it is judged to be not less than, it is considered as current rising, and the number of consecutive rises is recorded; Determine whether the number of consecutive increases exceeds a threshold; If it is determined to be exceeded, the average value of the motor rotation angle calculated by RLS_Threshold3 is used as the touch plate rotation angle.

5. The method according to claim 4, characterized in that The method of using RLS_Threshold3 as the current parameter in the updated mathematical model to calculate the contact disc rotation angle of the motor corresponding to the contact point further includes: If it is determined to be less than, the contact disc angle of the motor corresponding to the contact point is calculated using the updated third current threshold.

6. The method according to claim 5, characterized in that The step of calculating the contact disk rotation angle of the motor corresponding to the contact point using the updated third current threshold comprises: calculating the touch disc rotation angle based on a third current threshold; and The recorded number of consecutive rises and the corresponding calculated average value of the motor rotation angle are cleared.

7. A brake contact point identification device, characterized in that: in, The brake comprises a motor, a caliper and a brake disc; The device comprises: a control module, configured to control the motor to drive the caliper to approach and squeeze the brake disc when the caliper is separated from the brake disc; an acquisition module, configured to acquire current parameters flowing through the motor and rotation angle parameters of the motor; A construction module is used to construct an initial mathematical model between the current flowing through the motor and the rotation angle of the motor; wherein the initial mathematical model is: ； Where i k is the kth current parameter after the caliper contacts the brake disc, , a1,…,a n are the coefficients of the initial mathematical model, , x k is the kth rotation angle parameter after the caliper contacts the brake disc; an obtaining module, configured to obtain the model coefficients by using a recursive least squares parameter identification method in combination with the rotation angle parameters to obtain an updated mathematical model; a calculation module, configured to calculate a contact disc rotation angle of the motor corresponding to the contact point based on a minimum absolute value of the current corresponding to a stage in which the absolute value of the current increases and the updated mathematical model; In the process of calculating the contact disc angle of the motor corresponding to the contact point based on the minimum absolute value of the current corresponding to the stage of increasing absolute value of the current and the updated mathematical model, the calculation module is specifically used to: determine whether the current parameter satisfies both the first condition and the second condition; wherein the first condition is: ； The second condition is: ； Where i is the current parameter, RLS_Threshold1 is the dynamic trigger threshold, i fitted is a fitting current parameter calculated based on the current parameter and the updated mathematical model, and RLS_Threshold2 is a residual tolerance threshold. If it is determined that both the first and second conditions are satisfied, RLS_Threshold3 is used as the current parameter in the updated mathematical model to calculate the contact disc angle of the motor corresponding to the contact point. RLS_Threshold3 is a third current threshold. The third current threshold is calculated according to the following formula: ； Wherein, RLS_Threshold3 is the third current threshold, I avg_current The minimum value of the average value of the absolute current calculated at present, I0 is a constant.

8. An electronic brake, characterized in that: include: Brakes and controllers, The controller is electrically connected to the brake; The controller is configured to control the brake according to the method according to any one of claims 1 to 6.

9. A storage medium, characterized in that: The storage medium comprises a computer-readable storage medium; a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the method according to any one of claims 1 to 6 is executed.

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