Electronic parking brake caliper gap adaptive compensation method and system

Abstract

This invention relates to the field of clearance analysis technology and discloses an adaptive compensation method and system for electronic parking brake caliper clearance. The method includes: acquiring caliper operating data during electronic parking brake operation; identifying the pre-processed operating data; removing distorted and abnormal data; and generating a multi-cycle braking set representing caliper braking changes under different braking frequencies. Based on the multi-cycle braking set, the cumulative wear of the brake disc and brake pads is analyzed to obtain a brake wear change sequence representing the cumulative wear of the brake disc and brake pads as the number of braking cycles increases. This solution can dynamically adjust the compensation amount based on multi-cycle wear, improve the adaptive accuracy of brake clearance during long-term driving, avoid the accumulation of clearance errors caused by gradual uniform wear, and ensure the safety of electronic parking brakes.

Description

Technical Field

[0001] This invention relates to the field of clearance analysis technology, specifically to an adaptive compensation method and system for electronic parking brake caliper clearance. Background Technology

[0002] The logic of clearance compensation in existing electronic parking calipers is as follows: after each parking lock, unlock, and reset action, the controller determines that the braking is in place by detecting the motor stall current, and then performs a single clearance compensation calibration. The compensation amount is calculated based on the single braking stroke data. After the single action is completed, the clearance parameters are locked, waiting for the next parking cycle to trigger compensation.

[0003] However, the above compensation method still has the following drawbacks: During long-term vehicle operation, the brake disc and brake pads will experience progressive and uniform wear. This cumulative wear will cause changes in the clearance. However, single-trigger compensation can only adapt to instantaneous clearance deviations and cannot identify clearance errors accumulated over multiple braking cycles, thus affecting clearance compensation. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an adaptive compensation method and system for electronic parking brake caliper clearance, which solves the aforementioned problems.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0006] An adaptive compensation method for electronic parking brake caliper clearance includes:

[0007] Step S1: Obtain the caliper's operating data during electronic parking brake operation, identify the preprocessed operating data, remove distorted and abnormal data, and generate a multi-cycle braking set representing the caliper braking changes under different braking frequencies.

[0008] Step S2: Based on the multi-cycle braking set, analyze the cumulative wear of the brake disc and brake pads to obtain a brake wear change sequence that represents the cumulative wear of the brake disc and brake pads as the number of braking cycles increases.

[0009] Step S3: Based on the brake wear change sequence, analyze the cumulative clearance offset error caused by continuous wear and the instantaneous clearance fluctuation deviation caused by a single braking, and obtain the caliper clearance deviation value representing the long-term cumulative error of brake wear and the instantaneous error of single braking fluctuation.

[0010] Step S4: Perform joint calculation on caliper clearance deviation value and brake wear change sequence, analyze wear change trend, and obtain adaptive clearance compensation coefficient.

[0011] Furthermore, the preprocessed operational data is identified, distorted and abnormal data are removed, and a multi-cycle braking set representing caliper braking changes at different braking frequencies is generated, including:

[0012] For the preprocessed operating data, distorted and abnormal data are identified and removed to obtain braking condition characteristic values ​​that represent the matching degree between the mechanical action of the caliper and the electronic control response under a single braking cycle.

[0013] Based on the characteristic values ​​of braking conditions, a hierarchical mapping is performed to analyze the effective braking under each gradient frequency, and a multi-cycle braking set representing the caliper braking changes under different braking frequencies is generated.

[0014] Furthermore, based on the multi-cycle braking set, the cumulative wear of the brake disc and brake pads is analyzed to obtain a brake wear change sequence representing the cumulative wear of the brake disc and brake pads as the number of braking cycles increases, including:

[0015] Based on the multi-cycle braking set, the effect of each braking frequency on the caliper braking fit is analyzed, and the braking condition weights representing the proportion of effective matching between electronic control and mechanical braking under each braking cycle are obtained.

[0016] Furthermore, based on the multi-cycle braking set, the cumulative wear of the brake disc and brake pads is analyzed to obtain a brake wear change sequence representing the wear accumulation of the brake disc and brake pads with increasing braking cycles, which also includes:

[0017] The braking condition weights are combined with the multi-cycle braking set to calculate the effective wear amplitude representing the friction between the brake disc and brake pads during a single braking process.

[0018] Based on the effective wear amplitude and multi-cycle braking set, the trend of brake wear is analyzed, and a cumulative wear offset value representing the degree of brake wear at each frequency gradient is generated.

[0019] Furthermore, based on the multi-cycle braking set, the cumulative wear of the brake disc and brake pads is analyzed to obtain a brake wear change sequence representing the wear accumulation of the brake disc and brake pads with increasing braking cycles, which also includes:

[0020] Based on the cumulative wear offset value and the effective wear amplitude, the dynamic changes in the wear of the brake disc and brake pads with the increase of the number of braking cycles are analyzed, resulting in a brake wear change sequence that represents the cumulative wear of the brake disc and brake pads with the increase of the number of braking cycles.

[0021] Furthermore, based on the brake wear change sequence, the cumulative clearance offset error caused by continuous wear and the instantaneous clearance fluctuation deviation caused by a single braking event are analyzed to obtain the caliper clearance deviation value, which represents the cumulative error of long-term brake wear and the transient error of single braking fluctuation, including:

[0022] Based on the brake wear change sequence, the gap change between the brake disc and brake pads under long-term continuous wear is analyzed to obtain the steady-state reference error value representing the caliper gap.

[0023] Furthermore, based on the brake wear change sequence, the cumulative clearance offset error caused by continuous wear and the instantaneous clearance fluctuation deviation caused by a single braking event are analyzed to obtain the caliper clearance deviation value representing the long-term cumulative error of brake wear and the transient error of single braking fluctuation. This also includes:

[0024] Based on the brake wear change sequence, the instantaneous gap fluctuation deviation of a single braking action is analyzed to obtain the single-cycle transient fluctuation value representing the dynamic random error of a single braking action.

[0025] By fusing the steady-state reference error value and the single-cycle transient fluctuation value, the caliper clearance deviation value, which represents the cumulative error of long-term braking wear and the transient error of single braking fluctuation, is obtained.

[0026] Furthermore, the caliper clearance deviation and brake wear change sequence are calculated together to analyze the wear change trend and obtain the adaptive clearance compensation coefficient, including:

[0027] The caliper clearance deviation value and the brake wear change sequence are calculated together to analyze the changes in wear rate and clearance error under different braking frequencies, and the wear change coefficient representing the degree of dynamic evolution of clearance wear is obtained.

[0028] Furthermore, the caliper clearance deviation and brake wear change sequence are calculated together to analyze the wear change trend and obtain the adaptive clearance compensation coefficient. This also includes:

[0029] The wear variation coefficient and steady-state reference error value are calculated to generate an adaptive clearance compensation coefficient that adapts to different wear conditions.

[0030] Furthermore, an electronic parking brake caliper clearance adaptive compensation system, applied to the above-mentioned compensation method, includes:

[0031] The data processing unit is used to acquire the caliper's operating data during electronic parking brake operation, identify the pre-processed operating data, remove distorted and abnormal data, and generate a multi-cycle braking set representing the caliper's braking changes under different braking frequencies.

[0032] The wear analysis unit is used to analyze the cumulative wear of the brake disc and brake pads based on the multi-cycle braking set, and obtain the brake wear change sequence representing the wear accumulation of the brake disc and brake pads as the number of braking cycles increases;

[0033] The clearance calculation unit is used to analyze the cumulative clearance offset error caused by continuous wear and the instantaneous clearance fluctuation deviation caused by a single braking based on the brake wear change sequence, and obtain the caliper clearance deviation value representing the long-term cumulative error of brake wear and the instantaneous error of single braking fluctuation.

[0034] The clearance compensation unit is used to perform collaborative calculations on the caliper clearance deviation value and the brake wear change sequence, analyze the wear change trend, and obtain the adaptive clearance compensation coefficient.

[0035] In summary, the present invention has the following main beneficial effects:

[0036] By removing distorted and abnormal data from the preprocessed operating data, a multi-cycle braking set is generated to reflect the caliper braking changes under different braking frequencies. Then, the brake wear change sequence is analyzed to fully understand the progressive wear trajectory of the brake disc and brake pads with increasing braking frequency. At the same time, the steady-state reference error value and the single-cycle transient fluctuation value are calculated and fused into the caliper clearance deviation value, which can capture the long-term cumulative offset and single random fluctuation of the clearance. Finally, the wear change coefficient and the steady-state reference error value are calculated together to obtain the adaptive clearance compensation coefficient. This solution can dynamically adjust the compensation amount according to the multi-cycle wear, improve the adaptive accuracy of the brake clearance during long-term driving, avoid the accumulation of clearance error caused by progressive uniform wear, and ensure the safety of electronic parking brake. Attached Figure Description

[0037] Figure 1 This is a step diagram of an electronic parking brake caliper gap adaptive compensation method according to the present invention;

[0038] Figure 2 This is a schematic diagram of an electronic parking brake caliper gap adaptive compensation system according to the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] refer to Figure 1 and Figure 2 An adaptive compensation method for electronic parking brake caliper clearance includes:

[0041] Step S1: Obtain the caliper's operating data during electronic parking brake operation, identify the preprocessed operating data, remove distorted and abnormal data, and generate a multi-cycle braking set representing the caliper braking changes under different braking frequencies.

[0042] The caliper's operating data includes: motor braking working stroke, motor reset and retraction stroke, parking brake execution time, and reset return execution time;

[0043] Among them, the working stroke of the electric motor brake is the displacement distance that the motor drives the caliper piston to push forward from the initial position when the vehicle applies the parking brake, until the brake pads press against the brake disc and the brake lock is completed;

[0044] The motor reset and retraction stroke is the retraction distance of the caliper piston driven by the motor from the brake locking position back to the initial position when the vehicle releases the parking brake.

[0045] The parking brake execution time is the total time from when the parking brake is locked until the motor stops running and the parking brake is determined to be locked in place.

[0046] The reset execution time is the total reset time from the time of unlock reset until the motor retracts and the piston is fully returned to its original position.

[0047] Step S2: Based on the multi-cycle braking set, analyze the cumulative wear of the brake disc and brake pads to obtain a brake wear change sequence that represents the cumulative wear of the brake disc and brake pads as the number of braking cycles increases.

[0048] Step S3: Based on the brake wear change sequence, analyze the cumulative clearance offset error caused by continuous wear and the instantaneous clearance fluctuation deviation caused by a single braking, and obtain the caliper clearance deviation value representing the long-term cumulative error of brake wear and the instantaneous error of single braking fluctuation.

[0049] Step S4: Perform joint calculation on caliper clearance deviation value and brake wear change sequence, analyze wear change trend, and obtain adaptive clearance compensation coefficient.

[0050] In one embodiment, the preprocessed operating data is identified, distorted and abnormal data is removed, and a multi-cycle braking set representing the caliper braking changes at different braking frequencies is generated, including:

[0051] For the preprocessed operating data, distorted and abnormal data are identified and removed to obtain braking condition characteristic values ​​representing the matching degree between the mechanical action of the caliper and the electronic control response under a single braking cycle. Specifically, this includes: aligning the time axis of four types of operating data within a single braking cycle, namely, motor braking working stroke, motor reset and retraction stroke, parking brake execution time, and reset return execution time; and calculating the stroke change rate corresponding to the unit time of braking phase, i.e., the ratio of motor braking working stroke to parking brake execution time, to obtain the braking ratio; and calculating the stroke change rate corresponding to the unit time of retraction phase, i.e., the ratio of motor reset and retraction stroke to reset return execution time, to obtain the retraction ratio.

[0052] Divide the retraction ratio by the braking ratio in all single braking cycles to obtain the ratio value, sort the ratio values ​​in order to form a sequence, calculate the minimum, maximum and median of the sequence. If the ratio value of the cycle is less than the smaller of the minimum and the median or greater than the larger of the maximum and the median, it is determined that the cycle contains distorted abnormal data and is removed.

[0053] For each retained single braking cycle, it is considered a valid cycle. The square root of the retraction ratio multiplied by the braking ratio is then multiplied by the ratio of the smaller to the larger value of the parking brake execution time and the reset execution time within that single braking cycle. The calculation result is then normalized to the 0-1 range to obtain the braking condition characteristic value representing the matching degree between the caliper mechanical action and the electronic control response under a single braking cycle.

[0054] Based on the characteristic values ​​of braking conditions, a hierarchical mapping is performed to analyze the effective braking under each gradient frequency, and a multi-cycle braking set representing the caliper braking changes under different braking frequencies is generated. Specifically, the total number of all effective braking cycles is taken as N, and the number of cycles L that each gradient layer should contain is taken as the number of cycles after rounding down the arithmetic square root of N. All effective cycles are divided into continuous gradient layers according to the time sequence of braking occurrence, and each gradient layer contains L cycles. If the last layer has less than L cycles, it is merged into the previous layer.

[0055] For each gradient layer, the median of the braking condition feature values ​​of all cycles within that layer is calculated as the representative matching degree of that frequency gradient. At the same time, the cumulative value of the motor braking stroke and the cumulative value of the motor reset and retraction stroke of all cycles within that layer are extracted. Both are divided by the number of cycles L of that layer to obtain the average braking stroke and average retraction stroke of that gradient layer. All effective cycles are numbered sequentially from 1 to N according to their occurrence time. This number is the braking sequence index.

[0056] The representative matching degree, average braking stroke, average retraction stroke, number of cycles within the layer, and corresponding braking sequence index of each gradient layer are stored together to form a multi-cycle braking set representing the caliper braking changes under different braking frequencies.

[0057] By analyzing the preprocessed operating data, distorted and abnormal data are removed, and the effective braking cycles are selected using the ratio of braking ratio to retraction ratio. This avoids interference from single instantaneous clearance deviations on the overall judgment. Furthermore, the characteristic values ​​of the braking condition are calculated, reflecting the matching degree between the mechanical action of the caliper and the electronic control response under a single braking cycle. Based on this, all effective cycles are mapped in chronological order, and the representative matching degree, average braking stroke, and average retraction stroke of each gradient layer are extracted to form a multi-cycle braking set that reflects the changes in caliper braking under different braking frequencies. This further helps to understand the uniform wear pattern accumulated by the brake disc and brake pads in multiple cycles, making up for the shortcomings of traditional single-trigger compensation, which only adapts to instantaneous clearance deviations.

[0058] In one embodiment, based on a multi-cycle braking set, the cumulative wear of the brake disc and brake pads is analyzed to obtain a brake wear change sequence representing the cumulative wear of the brake disc and brake pads as the number of braking cycles increases, including:

[0059] Based on the multi-cycle braking set, the effect of each braking frequency on the caliper braking fit is analyzed to obtain the braking condition weight representing the effective matching ratio of electronic and mechanical braking under each braking cycle. Specifically, in the multi-cycle braking set, for each gradient layer, the absolute value of the difference between the average braking stroke and the average retraction stroke of that layer is calculated, and then the sum of the two is calculated. Then, the ratio of the absolute value to the sum is subtracted from 1 to obtain the stroke matching degree of that layer. The closer the stroke matching degree is to 1, the more symmetrical the stroke in the braking and retraction directions is, and the less wear there is.

[0060] Multiply the stroke matching degree of the layer by the representative matching degree of the layer to obtain the bonding effect value of the layer. After performing the above calculation for all gradient layers in sequence, sum the bonding effect values ​​of all layers to obtain the total. Divide the bonding effect value of each layer by the total to obtain the braking condition weight representing the effective matching ratio of electronic control and mechanical braking under each braking cycle. The sum of the braking condition weights of all layers is 1.

[0061] In one embodiment, based on a multi-cycle braking set, the cumulative wear of the brake disc and brake pads is analyzed to obtain a brake wear change sequence representing the cumulative wear of the brake disc and brake pads as the number of braking cycles increases. This also includes:

[0062] The braking condition weights are combined with the multi-cycle braking set to calculate the effective wear amplitude generated by the contact friction between the brake disc and brake pad during a single braking process. Specifically, for each gradient layer in the multi-cycle braking set, the difference between the average braking stroke and the average retraction stroke within that layer is calculated. This difference reflects the net increase in braking stroke caused by wear accumulation. Since the distance the piston pushes forward during braking minus the distance it retracts during retraction, the difference is equal to the amount of clearance that needs to be compensated for due to wear. This amount of clearance is directly related to the effective wear generated by the contact friction.

[0063] Multiply the difference by the braking condition weight of the layer to obtain the weighted net wear difference value corresponding to the gradient layer. Divide the weighted net wear difference value by the number of cycles within the layer to obtain the effective wear amplitude representing the friction between the brake disc and brake pad during a single braking process within the gradient layer.

[0064] Based on the effective wear amplitude and the multi-cycle braking set, the trend of braking wear is analyzed, and a cumulative wear offset value representing the degree of braking wear under each frequency gradient is generated. Specifically, for the multi-cycle braking set, each gradient layer is arranged according to the order of braking sequence index to form a sequence in which the effective wear amplitude increases with the braking frequency; the ratio of the effective wear amplitude of two adjacent gradient layers in the sequence is calculated. If the ratio is greater than the ratio of the previous layer to the layer before that, the wear is determined to be an aggravating trend, otherwise it is a mitigating trend.

[0065] To correct the cumulative calculation deviation under different frequencies, starting from the first layer, the effective wear amplitude of each layer is compared with the arithmetic mean of the effective wear amplitudes of all previous layers. For the first layer, since there is no previous data, its single-layer wear deviation is 0. For the second layer and each subsequent layer, the effective wear amplitude of the layer is calculated by subtracting the arithmetic mean of the effective wear amplitudes of the previous layers from the effective wear amplitude of the layer. The difference is then multiplied by the number of cycles within the layer to obtain the single-layer wear deviation of the layer.

[0066] The wear deviation of each gradient layer is accumulated layer by layer in gradient order. The accumulated result of the first layer is the wear deviation of the first layer, which is 0. The accumulated result of the second layer is the sum of the wear deviations of the first and second layers. The accumulated result of the third layer is the sum of the wear deviations of the first three layers, and so on. The accumulated result of each layer is the cumulative wear offset value of the braking wear degree corresponding to each gradient layer. This cumulative wear offset value reflects the total cumulative wear deviation from the first braking to the end of the current frequency gradient. The aggravation trend segment has a positive offset due to the positive wear acceleration, and the relief trend segment has a negative offset due to the negative wear acceleration.

[0067] In one embodiment, based on a multi-cycle braking set, the cumulative wear of the brake disc and brake pads is analyzed to obtain a brake wear change sequence representing the cumulative wear of the brake disc and brake pads as the number of braking cycles increases. This also includes:

[0068] Based on the cumulative wear offset value and effective wear amplitude, the dynamic changes in the wear of the brake disc and brake pads with increasing braking frequency are analyzed, resulting in a brake wear change sequence representing the wear accumulation of the brake disc and brake pads with increasing braking frequency. The specific calculation formula is as follows: For each gradient layer, the layers are arranged according to the braking sequence index. Let the wear accumulation before the first braking, i.e., the 0th braking, be the... =0;

[0069] For each gradient layer k, this layer contains In each braking cycle, the effective wear amplitude of this layer is recorded as... The cumulative wear offset value is denoted as First, calculate the cumulative wear of the base layer. , ,in, Then, the cumulative wear offset value is added as a correction term to obtain the cumulative wear amount at the end of the layer. = + Indicates the first The cumulative wear at the end of each gradient layer;

[0070] For the cumulative wear of the first gradient layer + Within this layer, the cumulative wear after each braking increases uniformly according to the braking sequence: the cumulative wear after the first braking is equal to... Divide by The cumulative wear after the second braking is equal to Multiply by 2 and then divide by And so on, the first The cumulative wear after each braking event is equal to Multiply Divide by Until the The cumulative wear after each braking event is equal to ;

[0071] in, The effective wear amplitude of the first gradient layer. For the braking cycle of the first gradient layer, This represents the cumulative wear offset value for the first gradient layer;

[0072] For the second gradient layer, this layer contains The cumulative wear at the end of the previous braking cycle is: The cumulative wear at the end of this layer = + The first braking within this layer, i.e., the first The cumulative wear after +1 braking is equal to ( minus Divide by Added later The cumulative wear after the second braking within this layer is equal to ( minus Multiply by 2 and then divide by Added later Similarly, the cumulative wear after the i-th braking event within this layer is equal to ( minus Multiply by i and then divide by Add The cumulative wear until the last braking of this layer equals ;

[0073] in, The effective wear amplitude of the second gradient layer. For the braking cycle of the second gradient layer, This represents the cumulative wear offset value for the second gradient layer.

[0074] The third and subsequent gradient layers are calculated in the same way as the second gradient layer, thus obtaining the cumulative wear amount of each braking in each gradient layer. The cumulative wear amount after each braking in all gradient layers is arranged in order of braking sequence index to form a sequence corresponding to the number of braking. This sequence is the braking wear change sequence, which is mainly used to reflect the continuous dynamic change trajectory of the wear amount of the brake disc and brake pads as the number of braking increases.

[0075] By calculating the stroke matching degree and representative matching degree of each gradient layer through multi-cycle braking set, the braking condition weight is obtained, which reflects the effective matching ratio of electronic control and mechanical braking at different frequencies. Then, the effective wear amplitude is calculated to accurately reflect the wear amount generated by the contact friction between the brake disc and brake pad during a single braking process. By calculating the ratio of the wear amplitude of adjacent layers, the wear intensification or mitigation trend is determined. Finally, a brake wear change sequence that continuously increases with the number of braking cycles is generated to improve the accuracy of clearance compensation.

[0076] In one embodiment, based on the brake wear change sequence, the cumulative clearance offset error caused by continuous wear and the instantaneous clearance fluctuation deviation caused by a single braking event are analyzed to obtain the caliper clearance deviation value, which represents the long-term cumulative error of brake wear and the transient error of single braking fluctuation, including:

[0077] Based on the brake wear variation sequence, the gap change of the brake disc and brake pads under long-term continuous wear is analyzed to obtain the steady-state reference error value representing the caliper gap. Specifically, this includes: calculating the sum of all values ​​in the brake wear variation sequence to obtain the total cumulative wear; dividing this sum by the total number of braking cycles to obtain the average cumulative wear amount. This average cumulative wear amount reflects the overall concentration trend of wear amount throughout the entire braking cycle, is not dominated by single abnormal fluctuations, and fully determines the continuous cumulative effect of wear. The average cumulative wear amount is used as the steady-state reference error value representing the caliper gap. The steady-state reference error value represents the increase in the gap between the initial position of the caliper piston and the brake disc caused by the long-term continuous wear of the brake disc and brake pads throughout the entire braking cycle.

[0078] In one embodiment, based on the brake wear change sequence, the cumulative clearance offset error caused by continuous wear and the instantaneous clearance fluctuation deviation caused by a single braking event are analyzed to obtain a caliper clearance deviation value representing the long-term cumulative brake wear error and the instantaneous error of a single braking event. The method further includes:

[0079] Based on the brake wear change sequence, the instantaneous clearance fluctuation deviation of a single braking event is analyzed to obtain the single-cycle transient fluctuation value representing the dynamic random error of a single braking event. Specifically, for the brake wear change sequence, starting from the first braking event, the wear increment generated by each braking event is calculated sequentially: that is, the cumulative wear after the end of the current braking event is subtracted from the cumulative wear after the end of the previous braking event, and the difference is the actual increase in clearance caused by contact friction during the current braking event, which is the wear increment; the above calculation is performed for all braking events to obtain a set of wear increment sequences that correspond one-to-one with the number of braking events.

[0080] The average wear increment for each braking event is obtained by summing all wear increments in the wear increment sequence and dividing by the total number of braking events. For each braking event, the average wear increment is subtracted from its wear increment. The difference is the single-cycle transient fluctuation value of the dynamic random error of a single braking event. The single-cycle transient fluctuation value can be positive or negative. A positive value indicates that the gap offset generated by this braking event is greater than the average level, reflecting mechanical shock or excessive electronic control response. A negative value indicates that the gap offset is less than the average level, reflecting weak braking or excessive backing.

[0081] By fusing the steady-state reference error value and the single-cycle transient fluctuation value, a caliper clearance deviation value representing the cumulative error of long-term brake wear and the transient error of a single brake fluctuation is obtained. Specifically, this involves: calculating the square of all single-cycle transient fluctuation values, summing all the squared values ​​and dividing by the total number of braking cycles to obtain the mean square value of the fluctuation, which reflects the energy level of the random deviation of a single braking cycle; adding the mean square value of the fluctuation to the square of the steady-state reference error value, and then taking the square root to obtain the caliper clearance deviation value representing the cumulative error of long-term brake wear and the transient error of a single brake fluctuation. This superposition method avoids the mutual cancellation of positive and negative fluctuations.

[0082] In one embodiment, the caliper clearance deviation value and the brake wear change sequence are calculated collaboratively to analyze the wear change trend and obtain an adaptive clearance compensation coefficient, including:

[0083] The caliper clearance deviation value and the brake wear change sequence are calculated together. The wear growth rate and clearance error under different braking frequencies are analyzed to obtain the wear change coefficient representing the dynamic evolution of clearance wear. Specifically, the brake wear change sequence is divided into a sub-interval for every ten consecutive braking events according to the braking sequence. The first sub-interval covers the first to the tenth braking events. Its initial wear accumulation is the value W(0) before the first braking event, which is 0. The final wear accumulation is W(10). The wear increment of this sub-interval is W(10) minus W(0).

[0084] The second sub-interval covers the 11th to 20th braking events. The initial wear accumulation is W(10), the final wear accumulation is W(20), and the wear increment is W(20) minus W(10). This process is repeated to obtain the wear sequence of each sub-interval.

[0085] The ratio of the standard deviation to the arithmetic mean of all values ​​in the wear sequence is calculated to obtain the coefficient of variation of the wear increment in the sub-interval. The coefficient of variation is mainly used to reflect the degree of fluctuation of the wear rate under different braking frequencies. Then, the caliper clearance deviation value is multiplied by the coefficient of variation to obtain the wear variation coefficient. The wear variation coefficient represents the compensation sensitivity reserved to cope with the drastic changes in the wear rate based on the comprehensive deviation level. Its value increases or decreases synchronously with the degree of wear fluctuation.

[0086] In one embodiment, the caliper clearance deviation value and the brake wear change sequence are calculated together to analyze the wear change trend and obtain an adaptive clearance compensation coefficient. The method also includes:

[0087] The wear variation coefficient and steady-state reference error value are calculated to generate an adaptive clearance compensation coefficient that adapts to different wear conditions. Specifically, the wear variation coefficient is added to the steady-state reference error value to obtain the adaptive clearance compensation coefficient, which can adapt to the clearance variation requirements under different wear conditions.

[0088] The average cumulative wear is calculated by the brake wear change sequence to obtain the steady-state reference error value, which accurately reflects the increasing trend of caliper clearance caused by long-term continuous wear between the brake disc and brake pads. At the same time, the transient fluctuation value of a single cycle is extracted by the difference between the wear increment and the average wear increment, which reflects the dynamic random error of a single braking action, and the caliper clearance deviation value is calculated. This preserves the long-term cumulative effect and avoids the mutual cancellation of positive and negative fluctuations. In addition, the coefficient of variation of the wear increment in the sub-interval is calculated based on the brake wear change sequence to obtain the wear change coefficient, which is superimposed with the steady-state reference error value to generate an adaptive clearance compensation coefficient. The adaptive clearance compensation coefficient can increase or decrease synchronously with the violent fluctuation of the wear rate, dynamically adapting to the clearance change requirements under different frequencies, and improving the compensation accuracy of electronic parking calipers under progressive uniform wear conditions.

[0089] In one embodiment, an electronic parking brake caliper clearance adaptive compensation system is applied to the above-described compensation method, comprising:

[0090] The data processing unit is used to acquire the caliper's operating data during electronic parking brake operation, identify the pre-processed operating data, remove distorted and abnormal data, and generate a multi-cycle braking set representing the caliper's braking changes under different braking frequencies.

[0091] The wear analysis unit is used to analyze the cumulative wear of the brake disc and brake pads based on the multi-cycle braking set, and obtain the brake wear change sequence representing the wear accumulation of the brake disc and brake pads as the number of braking cycles increases;

[0092] The clearance calculation unit is used to analyze the cumulative clearance offset error caused by continuous wear and the instantaneous clearance fluctuation deviation caused by a single braking based on the brake wear change sequence, and obtain the caliper clearance deviation value representing the long-term cumulative error of brake wear and the instantaneous error of single braking fluctuation.

[0093] The clearance compensation unit is used to perform collaborative calculations on the caliper clearance deviation value and the brake wear change sequence, analyze the wear change trend, and obtain the adaptive clearance compensation coefficient.

[0094] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An electronic parking brake caliper gap self-adapting compensation method, characterized in that, include: Step S1: Obtain the caliper's operating data during electronic parking brake operation, identify the preprocessed operating data, remove distorted and abnormal data, and generate a multi-cycle braking set representing the caliper braking changes under different braking frequencies. Step S2: Based on the multi-cycle braking set, analyze the cumulative wear of the brake disc and brake pads to obtain a brake wear change sequence that represents the cumulative wear of the brake disc and brake pads as the number of braking cycles increases. Step S3: Based on the brake wear change sequence, analyze the cumulative clearance offset error caused by continuous wear and the instantaneous clearance fluctuation deviation caused by a single braking, and obtain the caliper clearance deviation value representing the long-term cumulative error of brake wear and the instantaneous error of single braking fluctuation. Step S4: Perform joint calculation on caliper clearance deviation value and brake wear change sequence, analyze wear change trend, and obtain adaptive clearance compensation coefficient.

2. The electronic parking brake caliper clearance adaptive compensation method according to claim 1, characterized in that, The preprocessed operational data is identified, distorted and abnormal data are removed, and a multi-cycle braking set representing caliper braking changes at different braking frequencies is generated, including: For the preprocessed operating data, distorted and abnormal data are identified and removed to obtain braking condition characteristic values ​​that represent the matching degree between the mechanical action of the caliper and the electronic control response under a single braking cycle. Based on the characteristic values ​​of braking conditions, a hierarchical mapping is performed to analyze the effective braking under each gradient frequency, and a multi-cycle braking set representing the caliper braking changes under different braking frequencies is generated.

3. The electronic parking brake caliper clearance adaptive compensation method according to claim 2, characterized in that, Based on the multi-cycle braking set, the cumulative wear of the brake disc and brake pads is analyzed to obtain a brake wear change sequence representing the cumulative wear of the brake disc and brake pads as the number of braking cycles increases, including: Based on the multi-cycle braking set, the effect of each braking frequency on the caliper braking fit is analyzed, and the braking condition weights representing the proportion of effective matching between electronic control and mechanical braking under each braking cycle are obtained.

4. The electronic parking brake caliper clearance adaptive compensation method according to claim 3, characterized in that, Based on the multi-cycle braking set, the cumulative wear of the brake disc and brake pads is analyzed to obtain a brake wear change sequence representing the wear accumulation of the brake disc and brake pads with increasing braking cycles. This also includes: The braking condition weights are combined with the multi-cycle braking set to calculate the effective wear amplitude representing the friction between the brake disc and brake pads during a single braking process. Based on the effective wear amplitude and multi-cycle braking set, the trend of brake wear is analyzed, and a cumulative wear offset value representing the degree of brake wear at each frequency gradient is generated.

5. The electronic parking brake caliper clearance adaptive compensation method according to claim 4, characterized in that, Based on the multi-cycle braking set, the cumulative wear of the brake disc and brake pads is analyzed to obtain a brake wear change sequence representing the wear accumulation of the brake disc and brake pads with increasing braking cycles. This also includes: Based on the cumulative wear offset value and the effective wear amplitude, the dynamic changes in the wear of the brake disc and brake pads with the increase of the number of braking cycles are analyzed, resulting in a brake wear change sequence that represents the cumulative wear of the brake disc and brake pads with the increase of the number of braking cycles.

6. The electronic parking brake caliper clearance adaptive compensation method according to claim 5, characterized in that, Based on the brake wear change sequence, the cumulative clearance offset error caused by continuous wear and the instantaneous clearance fluctuation deviation caused by a single braking event are analyzed to obtain the caliper clearance deviation value representing the long-term cumulative error of brake wear and the transient error of single braking fluctuation, including: Based on the brake wear change sequence, the gap change between the brake disc and brake pads under long-term continuous wear is analyzed to obtain the steady-state reference error value representing the caliper gap.

7. The electronic parking brake caliper clearance adaptive compensation method according to claim 6, characterized in that, Based on the brake wear change sequence, the cumulative clearance offset error caused by continuous wear and the instantaneous clearance fluctuation deviation caused by a single braking event are analyzed to obtain the caliper clearance deviation value representing the long-term cumulative error of brake wear and the transient error of single braking fluctuation. This also includes: Based on the brake wear change sequence, the instantaneous gap fluctuation deviation of a single braking action is analyzed to obtain the single-cycle transient fluctuation value representing the dynamic random error of a single braking action. By fusing the steady-state reference error value and the single-cycle transient fluctuation value, the caliper clearance deviation value, which represents the cumulative error of long-term braking wear and the transient error of single braking fluctuation, is obtained.

8. The electronic parking brake caliper clearance adaptive compensation method according to claim 7, characterized in that, The caliper clearance deviation and brake wear variation sequence are calculated together to analyze the wear variation trend and obtain the adaptive clearance compensation coefficient, including: The caliper clearance deviation value and the brake wear change sequence are calculated together to analyze the changes in wear rate and clearance error under different braking frequencies, and the wear change coefficient representing the degree of dynamic evolution of clearance wear is obtained.

9. The electronic parking brake caliper clearance adaptive compensation method according to claim 8, characterized in that, The caliper clearance deviation and brake wear change sequence are calculated together to analyze the wear change trend and obtain the adaptive clearance compensation coefficient. This also includes: The wear variation coefficient and steady-state reference error value are calculated to generate an adaptive clearance compensation coefficient that adapts to different wear conditions.

10. An adaptive compensation system for electronic parking brake caliper clearance, applied in the compensation method as described in any one of claims 1-9, characterized in that, include: The data processing unit is used to acquire the caliper's operating data during electronic parking brake operation, identify the pre-processed operating data, remove distorted and abnormal data, and generate a multi-cycle braking set representing the caliper's braking changes under different braking frequencies. The wear analysis unit is used to analyze the cumulative wear of the brake disc and brake pads based on the multi-cycle braking set, and obtain the brake wear change sequence representing the wear accumulation of the brake disc and brake pads as the number of braking cycles increases; The clearance calculation unit is used to analyze the cumulative clearance offset error caused by continuous wear and the instantaneous clearance fluctuation deviation caused by a single braking based on the brake wear change sequence, and obtain the caliper clearance deviation value representing the long-term cumulative error of brake wear and the instantaneous error of single braking fluctuation. The clearance compensation unit is used to perform collaborative calculations on the caliper clearance deviation value and the brake wear change sequence, analyze the wear change trend, and obtain the adaptive clearance compensation coefficient.

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