Clamping force estimation method and device and vehicle

Abstract

The invention discloses a clamping force estimation method and device and a vehicle, and relates to the technical field of automobile brake control. The method comprises the steps that current caliper position information is obtained; and inputting the current caliper position information into the clamping force estimation model to obtain the clamping force corresponding to the current caliper position information. Therefore, the clamping force can be obtained by inputting the current caliper position information of the caliper friction plate into the clamping force estimation model, the problem that the clamping force can be obtained only by using a clamping force sensor which is high in price and high in installation requirement in the related technology is avoided, and the clamping force can be obtained even under the condition that the technical cost and the production cost are low. And the accurate control of the electronic mechanical braking system on the vehicle can also be realized.

Description

Technical Field

[0001] The present application relates to the technical field of automobile brake control, and in particular to a clamping force estimation method, device and vehicle. Background Art

[0002] With the popularization of vehicle intelligence and electrification, the electromechanical brake system (EMB) has replaced the electrohydraulic brake system and become an important research direction in the field of automotive brake control technology due to its many advantages such as high execution linearity, four-wheel independent control and low noise. In the process of completing braking through the electromechanical brake system, it is necessary to know the braking force of the vehicle wheel end, which is closely related to the different clamping forces applied to the caliper friction plate of the vehicle.

[0003] In the related art, the clamping force can be measured theoretically by a clamping force sensor. However, since the clamping force sensor is expensive and has very high installation requirements, it is actually difficult to install the clamping force sensor into the electronic mechanical brake system, and it is impossible to accurately measure the clamping force, which in turn affects the electronic mechanical brake system's precise control of the vehicle. Summary of the invention

[0004] The present application provides a clamping force estimation method, device and vehicle, which can achieve precise control of the vehicle by an electronic mechanical braking system with low technical cost and production cost.

[0005] This application discloses the following technical solutions:

[0006] In a first aspect, the present application provides a clamping force estimation method, the method comprising:

[0007] Get the current caliper position information;

[0008] The current caliper position information is input into a clamping force estimation model to obtain a clamping force corresponding to the current caliper position information.

[0009] Optionally, the clamping force estimation model is constructed by the following method:

[0010] Get the initial position of the caliper;

[0011] In the direction of increasing the stroke, the positive torque information corresponding to the current positive position information is obtained once every preset distance, and the positive position information is the sum of the initial position of the caliper and the product of the number of acquisitions and the preset distance; in the direction of decreasing the stroke, the negative torque information corresponding to the current negative position information is obtained once every preset distance, and the negative position information is the difference between the initial position of the caliper and the product of the number of acquisitions and the preset distance;

[0012] Acquire clamping force information corresponding to positive torque information and negative torque information, wherein the positive torque information and the negative torque information are torque information with equal distances from an initial position of the caliper and opposite directions;

[0013] The positive torque information and the negative torque information are used as input, and the clamping force information is used as output to train a neural network model to obtain a clamping force estimation model.

[0014] Optionally, the acquiring the clamping force information corresponding to the positive torque information and the negative torque information includes:

[0015] Taking the average value of the positive torque information and the negative torque information to obtain the average torque information;

[0016] The product of the average torque information and the transmission ratio is divided by the equivalent radius of the ball screw of the transmission structure to obtain the clamping force information corresponding to the positive torque information and the negative torque information.

[0017] Optionally, the acquiring the clamping force information corresponding to the positive torque information and the negative torque information includes:

[0018] Taking the average value of the positive torque information and the negative torque information to obtain the average torque information;

[0019] Obtaining comprehensive torque information according to the average torque information and the static friction equivalent torque information, wherein the static friction equivalent torque information is related to the output speed of the motor;

[0020] Acquiring comprehensive clamping force information corresponding to the comprehensive torque information;

[0021] The method of taking the positive torque information and the negative torque information as input and the clamping force information as output to train a neural network model comprises:

[0022] The comprehensive torque information is used as input, and the comprehensive clamping force information is used as output to train a neural network model.

[0023] Optionally, the taking the comprehensive torque information as input and the comprehensive clamping force information as output to train a neural network model includes:

[0024] If the magnitude of the comprehensive clamping force information is less than or equal to a preset threshold, the comprehensive torque information is used as input, and the comprehensive clamping force information is used as output to train the neural network model.

[0025] Optionally, the method further includes:

[0026] Inputting the verification caliper position information into the clamping force estimation model to obtain the verification clamping force corresponding to the verification caliper position information;

[0027] If the difference between the actual clamping force corresponding to the verification caliper position information and the verification clamping force is greater than or equal to a first preset threshold, it is determined that the operation is abnormal;

[0028] If it is determined that the number of abnormal operations is greater than a second preset threshold, the step of obtaining the initial position of the caliper is performed again.

[0029] Optionally, the method further includes:

[0030] When the current positive position information or the current negative position information reaches a preset position, if the motor speed fluctuation within a preset time is higher than a third preset threshold, it is determined that the operation is abnormal;

[0031] If it is determined that the number of abnormal operations is greater than a fourth preset threshold, the step of obtaining the initial position of the caliper is performed again.

[0032] Optionally, the method further includes:

[0033] If the absolute value of the difference between the positive torque information and the negative torque information is greater than the maximum value of all the positive torque information and the negative torque information, it is determined that the operation is abnormal;

[0034] If it is determined that the number of abnormal operations is greater than a fifth preset threshold, the step of obtaining the initial position of the caliper is performed again.

[0035] Optionally, the current caliper position information is related to current torque data, and the current torque data is the product of the motor torque coefficient and the current q-axis current of the motor.

[0036] In a second aspect, the present application provides a clamping force estimation device, the device comprising: an information acquisition module and a model output module;

[0037] The information acquisition module is used to obtain current caliper position information;

[0038] The model output module is used to input the current caliper position information into the clamping force estimation model to obtain the clamping force corresponding to the current caliper position information.

[0039] Optionally, the clamping force estimation model is constructed by the following modules:

[0040] A first acquisition module, used for acquiring an initial position of the caliper;

[0041] A second acquisition module is used to acquire positive torque information corresponding to the current positive position information once every preset distance in the stroke increasing direction, wherein the positive position information is the sum of the initial position of the caliper and the product of the number of acquisitions and the preset distance; and to acquire negative torque information corresponding to the current negative position information once every preset distance in the stroke decreasing direction, wherein the negative position information is the difference between the initial position of the caliper and the product of the number of acquisitions and the preset distance;

[0042] A third acquisition module is used to acquire clamping force information corresponding to positive torque information and negative torque information, wherein the positive torque information and the negative torque information are torque information with equal distances from the initial position of the caliper and opposite directions;

[0043] The model building module is used to take the positive torque information and the negative torque information as input, take the clamping force information as output, train a neural network model, and obtain a clamping force estimation model.

[0044] Optionally, the third acquisition module specifically includes: a first acquisition submodule and a second acquisition submodule;

[0045] The first acquisition submodule is used to average the positive torque information and the negative torque information to obtain average torque information;

[0046] The second acquisition submodule is used to obtain the clamping force information corresponding to the positive torque information and the negative torque information by dividing the product of the average torque information and the transmission ratio by the equivalent radius of the ball screw of the transmission structure.

[0047] Optionally, the third acquisition module specifically includes: a third acquisition submodule, a fourth acquisition submodule and a fifth acquisition submodule;

[0048] The third acquisition submodule is used to average the positive torque information and the negative torque information to obtain average torque information;

[0049] The fourth acquisition submodule is used to acquire comprehensive torque information according to the average torque information and the static friction equivalent torque information, wherein the static friction equivalent torque information is related to the output speed of the motor;

[0050] The fifth acquisition submodule is used to acquire comprehensive clamping force information corresponding to the comprehensive torque information;

[0051] The model training module is specifically used to train a neural network model by taking the comprehensive torque information as input and the comprehensive clamping force information as output.

[0052] Optionally, the model training module is specifically used to train a neural network model by taking the comprehensive torque information as input and the comprehensive clamping force information as output if the size of the comprehensive clamping force information is less than or equal to a preset threshold.

[0053] Optionally, the device further comprises: a verification input module, a first abnormality determination module and a first re-execution module;

[0054] The verification input module is used to input the verification caliper position information into the clamping force estimation model to obtain the verification clamping force corresponding to the verification caliper position information;

[0055] The first abnormality determination module is configured to determine that the operation is abnormal if the difference between the actual clamping force corresponding to the verification caliper position information and the verification clamping force is greater than or equal to a first preset threshold;

[0056] The first re-execution module is used to re-execute the acquisition of the caliper initial position if the number of times the operation is determined to be abnormal is greater than a second preset threshold.

[0057] Optionally, the device further comprises: a second abnormality determination module and a second re-execution module;

[0058] The second abnormality determination module is configured to determine that the operation is abnormal when the current positive position information or the current negative position information reaches a preset position and if the motor speed fluctuation within a preset time is higher than a third preset threshold;

[0059] The second re-execution module is used to re-execute the acquisition of the caliper initial position if the number of times the operation is determined to be abnormal is greater than a fourth preset threshold.

[0060] Optionally, the device further comprises: a third abnormality determination module and a third re-execution module;

[0061] The third abnormality determination module is configured to determine that the operation is abnormal if the absolute value of the difference between the positive torque information and the negative torque information is greater than the maximum value of all the positive torque information and the negative torque information;

[0062] The third re-execution module is used to re-execute the acquisition of the caliper initial position if the number of times the operation is determined to be abnormal is greater than a fifth preset threshold.

[0063] Optionally, the current caliper position information is related to current torque data, and the current torque data is the product of the motor torque coefficient and the current q-axis current of the motor.

[0064] In a third aspect, the present application provides a vehicle, the vehicle comprising a clamping force estimation device as described in the second aspect above, the clamping force estimation device being used to execute the clamping force estimation method described in the first aspect.

[0065] Compared with the prior art, this application has the following beneficial effects:

[0066] The present application provides a clamping force estimation method, device and vehicle, the method comprising: obtaining current caliper position information; inputting the current caliper position information into a clamping force estimation model to obtain the clamping force corresponding to the current caliper position information. Thus, the clamping force can be obtained by inputting the current caliper position information of the caliper friction plate into the clamping force estimation model, avoiding the problem in the related art that the clamping force must be obtained by using an expensive clamping force sensor with high installation requirements, and even when the technical cost and production cost are low, the electronic mechanical brake system can achieve precise control of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0068] Figure 1 A flow chart of a clamping force estimation method provided in an embodiment of the present application;

[0069] Figure 2 A schematic diagram of the structure of an electromechanical braking system provided in an embodiment of the present application;

[0070] Figure 3 A schematic diagram of a system for achieving travel control provided in an embodiment of the present application;

[0071] Figure 4 A schematic diagram of the relationship between stroke information and clamping force provided in an embodiment of the present application;

[0072] Figure 5 A schematic diagram of another relationship between stroke information and clamping force provided in an embodiment of the present application;

[0073] Figure 6 A schematic diagram of the relationship between the travel information and the clamping force of different friction plates provided in an embodiment of the present application;

[0074] Figure 7 A flow chart of difference verification of stroke information and torque information disclosed in an embodiment of the present application;

[0075] Figure 8 A flow chart of a stroke stability verification disclosed in an embodiment of the present application;

[0076] Fig. 9 A schematic diagram of a clamping force estimation device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0077] As described above, with the popularization of vehicle intelligence and electrification, the electronic mechanical braking system has replaced the electro-hydraulic braking system and become an important research direction in the field of automotive brake control technology due to its many advantages such as high execution linearity, four-wheel independent control and low noise.

[0078] The difference between the braking principle of the electromechanical brake system and the electrohydraulic brake system lies in the execution structure of the clamping and releasing of the caliper. Due to space limitations, the electromechanical brake system is suitable for using a wheel-end permanent magnet synchronous motor and a transmission mechanism with a high power density ratio to achieve the clamping and releasing of the caliper. After the friction plate and brake disc model of the caliper are determined, the magnitude of the braking force is directly related to the clamping force. At present, the magnitude of the clamping force can be measured theoretically by a clamping force sensor.

[0079] However, since clamping force sensors are expensive and have extremely high installation requirements, it is actually difficult to install clamping force sensors into electronic mechanical braking systems, making it impossible to accurately measure the size of the clamping force, which in turn affects the electronic mechanical braking system's precise control of the vehicle.

[0080] In view of this, the present application provides a clamping force estimation method, device and vehicle, the method comprising: obtaining current caliper position information; inputting the current caliper position information into a clamping force estimation model to obtain the clamping force corresponding to the current caliper position information. Thus, the clamping force can be obtained by inputting the current caliper position information of the caliper friction plate into the clamping force estimation model, avoiding the problem in the related art that the clamping force must be obtained by using an expensive clamping force sensor with high installation requirements, and even when the technical cost and production cost are low, the electronic mechanical brake system can achieve precise control of the vehicle.

[0081] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0082] See also Figure 1, which is a flow chart of a clamping force estimation method provided in an embodiment of the present application. The method comprises:

[0083] S101: Obtaining torque data and stroke data of the motor.

[0084] First, you need to obtain the motor's torque and travel data. Figure 2 , which is a schematic diagram of the structure of an electronic mechanical braking system provided in an embodiment of the present application. Figure 2 The electromechanical brake system shown obtains torque information and travel data from the electric motor.

[0085] The stroke data may refer to the stroke value of the caliper at a certain moment. Torque refers to the average torque output from the crankshaft end when the motor is running. Since there is no direct sensor for the torque of the motor, but the torque of the motor is related to the q-axis current of the motor, the torque data of the motor driven by a sine wave can be calculated by the following formula (1):

[0086] T motor =K T *i q (1)

[0087] Among them, T motor is the torque data, K T is the motor torque coefficient, i q is the q-axis current of the motor.

[0088] S102: Determine the initial position of the caliper based on the correspondence between the torque data and the stroke data.

[0089] After the torque data and stroke data of the motor are obtained, the corresponding relationship between the torque information and the stroke information can be determined, and the initial position of the caliper, that is, the zero position of the friction plate, can be obtained according to the corresponding relationship.

[0090] In some specific implementations, it is necessary to first clamp the brake pad with the first torque T1 of the motor to obtain the corresponding first motor stroke value P1, then clamp the brake pad with the second torque T2=1 / 2T1 of the motor to obtain the corresponding second motor stroke value P2, and then clamp the brake pad with the third torque T3=1 / 4T1 of the motor to obtain the corresponding third motor stroke value P3. Subsequently, in order to reduce the influence of static friction, the initial position of the caliper can be obtained by the difference method. For example, the initial position of the caliper can be calculated by the following formula (2):

[0091]

[0092] Among them, P0 is the initial position of the caliper, P1 is the first motor stroke value, P2 is the second motor stroke value, P3 is the third motor stroke value, T1 is the first torque, T2 is the second torque, and T3 is the third torque.

[0093] S103: In the forward direction of the travel, positive torque information corresponding to the current positive position information is obtained once every preset distance; in the backward direction of the travel, negative torque information corresponding to the current negative position information is obtained once every preset distance.

[0094] Since the initial position of the caliper has been obtained in step S102, the torque information corresponding to the current position information can be obtained once every preset distance Δ based on the initial position. It can be understood that the current position information refers to the initial position of the caliper and the sum or difference of the product of the preset distance Δ and the number of acquisitions.

[0095] That is to say, the electronic mechanical brake system needs to perform travel control every preset distance Δ in the direction of travel forward (increase). When the travel control reaches a steady state, the current forward position information (φ +1 ,φ +2 ,φ +3 ,…,φ +m Then, read the positive torque information (T +1 , T +2 , T +3 ,…,T +m ), the above T +1 , T +2 , T +3 ,…,T +m The equal positive torque information constitutes the positive control torque group.

[0096] Then, the electronic mechanical brake system needs to perform travel control again every preset distance Δ in the direction of travel retreat (reduction). When the travel control reaches a steady state, the current negative position information (φ -m ,…,φ -3 ,φ -2 ,φ -1 Then, read the negative torque information (T -m ,…,T -3 ,T -2 , T -1 ), the above T -m ,…,T -3 ,T -2 , T -1 Equal negative torque information constitutes a negative control torque group.

[0097] See also Figure 3 , which is a schematic diagram of a system for realizing stroke control provided by an embodiment of the present application. Figure 3 The structure shown completes the stroke control. It should be noted that this application does not limit the specific stroke control method.

[0098] S104: Obtain the clamping force corresponding to the motor torque according to the positive control torque group and the negative control torque group.

[0099] In some specific implementations, in order to obtain the clamping force corresponding to the motor torque, the average value of two torque information with equal distances and opposite directions from the initial position of the caliper can be taken. Specifically, the formula for taking the average value to obtain the torque average information can be shown as the following formula (3):

[0100]

[0101] Among them, T n is the average torque information, T +n is the positive torque information, T -n It is negative torque information.

[0102] Then, according to the transmission characteristics of the system, the corresponding clamping force can be obtained based on the average torque information. Specifically, the formula for obtaining the clamping force through the average torque information can be shown as the following formula (4):

[0103]

[0104] Among them, F Caliper is the clamping force, η is the transmission ratio, r is the equivalent radius of the ball screw of the transmission structure, T n It is the torque average information.

[0105] See also Figure 4 , which is a schematic diagram of the relationship between travel information and clamping force provided in an embodiment of the present application. Figure 4 It can be seen that the magnitude of the stroke information is positively correlated with the magnitude of the clamping force. It is understandable that the positive clamping force can be obtained based on the positive torque information first, and then the negative clamping force can be obtained based on the negative torque information. Subsequently, the average of the positive clamping force and the negative clamping force is taken to obtain the final clamping force information. Figure 5 , which is a schematic diagram of another relationship between stroke information and clamping force provided in an embodiment of the present application. Among them, the first curve is a curve corresponding to the stroke information and the positive clamping force, and the second curve is a curve corresponding to the stroke information and the negative clamping force. It should be noted that the present application does not limit the specific method for obtaining the clamping force.

[0106] It should be noted that the above method of obtaining the clamping force is only obtained through the clamping force equivalent torque information. In reality, since the static friction in the electronic mechanical brake system has a great influence on the calculation of the clamping force, the static friction equivalent torque information can also be considered in the direction of increasing and decreasing the stroke, and the clamping force equivalent torque information and the static friction equivalent torque information are integrated into the comprehensive torque information, and the corresponding clamping force is obtained according to the comprehensive torque information to reduce the error.

[0107] Exemplarily, the positive torque information (i.e., the positive comprehensive torque information) after considering the static friction equivalent torque can be expressed as the following formula (5):

[0108] T +n’ =T n +T friction (5)

[0109] Among them, T +n’ is the forward integrated torque information, T n is the average torque information, T friction is the static friction equivalent torque.

[0110] Similarly, the negative torque information (i.e., negative comprehensive torque information) after considering the static friction equivalent torque can be expressed as follows:

[0111] T -n’ =T n -T friction (6)

[0112] Among them, T -n’ is the negative integrated torque information, T n is the average torque information, T friction is the static friction equivalent torque.

[0113] Specifically, the static friction equivalent torque can be obtained by the following formula (7):

[0114]

[0115] Among them, T e is the motor output speed, w is the mechanical angular velocity, J is the motor moment of inertia, D is the rotation damping coefficient, T l is the equivalent clamping force torque at the motor end, and the average torque information T n Equal, φ trend is the travel trend. If the travel increases, the trend sgn(φ trend )=1, if the stroke decreases, define the trend sgn(φ trend )=-1.

[0116] Furthermore, the positive comprehensive torque information and the negative comprehensive torque information can be added together, and then an average value is obtained, and then the corresponding clamping force is calculated based on the average value. The specific acquisition method is shown in formulas (3) and (4), which will not be repeated here.

[0117] See also Figure 6 , which is a schematic diagram of the relationship between the travel information and the clamping force of different friction plates provided in the embodiment of the present application. Figure 6 It can be seen that as the degree of wear of the friction plate increases, the clamping force of the friction plate under the same stroke will also increase. Therefore, if the clamping force calculated by the above formula is lower than or equal to the preset threshold, it means that the friction plate can continue to be put into use, and the clamping force estimation model can be trained based on all the information corresponding to the friction plate.

[0118] In some specific implementations, after obtaining all the above position information, torque information, and travel direction, a table of position information and torque information can be prepared for storage. As shown in Table 1, this table is a table of position information and torque information provided in an embodiment of the present application.

[0119] Table 1

[0120]

[0121]

[0122] S105: Using the current position information as input and the clamping force as output, a neural network model is trained to obtain a clamping force estimation model.

[0123] After obtaining the current position information and the corresponding clamping force, the current position information is used as input and the corresponding clamping force is used as output to train the neural network model and obtain the clamping force estimation model.

[0124] It is understandable that if the static friction equivalent torque is taken into account, it is necessary to use the comprehensive torque information as input and the comprehensive clamping force information as output to train the neural network model and obtain the clamping force estimation model. This application does not make any limitation on this.

[0125] S106: Performing a difference verification of stroke information and torque information, a stroke stability verification, and / or a friction plate wear degree verification on the clamping force estimation model.

[0126] To ensure the accuracy of the training results, after the clamping force estimation model is trained, it is necessary to verify the clamping force estimation model again. For example, the clamping force estimation model can be verified by one or more of the following: difference verification of stroke information and torque information, stroke stability verification, and friction plate wear degree verification. If the verification passes, the clamping force estimation model can be put into use.

[0127] See also Figure 7 , which is a flow chart of a difference verification of stroke information and torque information disclosed in an embodiment of the present application. Specifically, the difference verification of stroke information and torque information means that since the stroke step is a preset distance Δ known, the position information shown in Table 1 is known. The controller can input the position information in Table 1 into the clamping force estimation model as the verification caliper position information to obtain the verification clamping force corresponding to the verification caliper position information. Subsequently, it is determined whether the difference between the actual clamping force sampled by the motor and the verification clamping force is less than the first preset threshold. If it is less than the first preset threshold, it is determined that the clamping force estimation model training is successful. If it is greater than or equal to the first preset threshold, it is determined that the operation is abnormal. If the number of abnormal operation determinations is greater than the second preset threshold, it is determined that the clamping force estimation model training has failed, and the initial position of the caliper needs to be re-acquired. It should be noted that the above-mentioned second preset threshold can be 3, 4, etc., and the specific first preset threshold and the second preset threshold are not limited in this application.

[0128] See also Figure 8 , which is a flow chart of a stroke stability verification disclosed in an embodiment of the present application. Specifically, the stroke stability verification means that after reaching the position corresponding to the preset target stroke information, that is, if the current positive position information or the current negative position information reaches the preset position, it can be determined whether the motor speed is stable, thereby determining that the controller stroke control has reached a stable state. Specifically, if the motor speed fluctuation at the sampling moment is greater than the third preset threshold within the set time, the sampling within the stroke range is abnormal, the motor torque sampling result is discarded, and the operation is determined to be abnormal. If the number of discards is greater than the fourth preset threshold, or the number of times the operation is determined to be abnormal is greater than the fourth preset threshold, it is determined that the training of the clamping force estimation model has failed, and the initial position of the caliper needs to be reacquired. It should be noted that the above-mentioned third preset threshold can be 50rpm (revolutions per minute), etc., and the above-mentioned fourth preset threshold can be 3, 4, etc. For the specific third preset threshold and fourth preset threshold, this application does not limit it.

[0129] Specifically, the verification of the degree of friction plate wear means that when the position corresponding to the position information in Table 1 is reached, it is necessary to obtain the torque information corresponding to each position information, and calculate whether the absolute value of the difference between the positive torque information and the negative torque information is greater than the maximum value of all the torque information. If so, the sampling is abnormal, the motor torque sampling result is discarded, and the operation is determined to be abnormal. If the number of discards is greater than the fifth preset threshold, or the number of times the operation is determined to be abnormal is greater than the fifth preset threshold, it is determined that the training of the clamping force estimation model has failed, and the initial position of the caliper needs to be reacquired. It should be noted that the above-mentioned fifth preset threshold can be 3, 4, etc., and this application does not limit the specific fifth preset threshold.

[0130] In addition, other types of verification can be performed. For example, it can be determined whether there are two adjacent training failure positions on all position information. If so, it is determined that the clamping force estimation model training has failed and the initial position of the caliper needs to be re-acquired.

[0131] Alternatively, it can also be determined whether the number of training failures on all position information exceeds n / 3. If so, it is determined that the training of the clamping force estimation model has failed and the initial position of the caliper needs to be re-acquired, where n is the number of calibrations in a single direction.

[0132] Alternatively, it is also possible to determine whether the difference between the clamping force corresponding to any positive torque information and the clamping force corresponding to the torque information of the initial position of the caliper is greater than the sixth preset threshold, or whether the difference between the clamping force corresponding to any negative torque information and the clamping force corresponding to the torque information of the initial position of the caliper is greater than the sixth preset threshold. If not, it is determined that the training of the clamping force estimation model has failed, and the initial position of the caliper needs to be reacquired. It should be noted that this application does not limit the specific sixth preset threshold.

[0133] S107: Inputting the current caliper position information into a clamping force estimation model to obtain the clamping force corresponding to the current caliper position information.

[0134] At any time after the clamping force estimation model is established, the current caliper position information can be obtained, and by inputting the caliper position information into the clamping force estimation model, the clamping force corresponding to the current caliper position information can be obtained.

[0135] In summary, the present application discloses a clamping force estimation method, which can obtain the clamping force by inputting the current caliper position information of the caliper friction plate into the clamping force estimation model, avoiding the problem that the clamping force must be obtained by using an expensive and high-installation clamping force sensor in the related art, and can achieve precise control of the vehicle by the electronic mechanical brake system even when the technical cost and production cost are low. In addition, the controller can also be used to give the motor a series of stroke angles, and the influence of dynamic and static friction can be removed by successive and positive and negative directions, and combined with the corresponding calculation strategy, so as to achieve precise control of the vehicle by the electronic mechanical brake system.

[0136] See also Fig. 9 , which is a clamping force estimation device provided in an embodiment of the present application. The clamping force estimation device 900 includes: an information acquisition module 901 and a model output module 902.

[0137] Specifically, the information acquisition module 901 is used to obtain the current caliper position information; the model output module 902 is used to input the current caliper position information into the clamping force estimation model to obtain the clamping force corresponding to the current caliper position information.

[0138] Optionally, the clamping force estimation model is constructed by the following modules:

[0139] A first acquisition module, used for acquiring an initial position of the caliper;

[0140] A second acquisition module is used to acquire positive torque information corresponding to the current positive position information once every preset distance in the stroke increasing direction, wherein the positive position information is the sum of the initial position of the caliper and the product of the number of acquisitions and the preset distance; and to acquire negative torque information corresponding to the current negative position information once every preset distance in the stroke decreasing direction, wherein the negative position information is the difference between the initial position of the caliper and the product of the number of acquisitions and the preset distance;

[0141] A third acquisition module is used to acquire clamping force information corresponding to positive torque information and negative torque information, wherein the positive torque information and the negative torque information are torque information with equal distances from the initial position of the caliper and opposite directions;

[0142] The model building module is used to take the positive torque information and the negative torque information as input, take the clamping force information as output, train the neural network model, and obtain the clamping force estimation model.

[0143] Optionally, the third acquisition module specifically includes: a first acquisition submodule and a second acquisition submodule;

[0144] Specifically, the first acquisition submodule is used to take the average value of the positive torque information and the negative torque information to obtain the average torque information; the second acquisition submodule is used to divide the product of the average torque information and the transmission ratio by the equivalent radius of the ball screw of the transmission structure to obtain the clamping force information corresponding to the positive torque information and the negative torque information.

[0145] Optionally, the third acquisition module specifically includes: a third acquisition submodule, a fourth acquisition submodule and a fifth acquisition submodule;

[0146] Specifically, the third acquisition submodule is used to average the positive torque information and the negative torque information to obtain the average torque information; the fourth acquisition submodule is used to acquire the comprehensive torque information according to the average torque information and the static friction equivalent torque information, and the static friction equivalent torque information is related to the output speed of the motor; the fifth acquisition submodule is used to acquire the comprehensive clamping force information corresponding to the comprehensive torque information;

[0147] Then, the above-mentioned model training module is specifically used to take the above-mentioned comprehensive torque information as input and the above-mentioned comprehensive clamping force information as output to train the neural network model.

[0148] Optionally, the model training module is specifically used to train a neural network model by taking the comprehensive torque information as input and the comprehensive clamping force information as output if the size of the comprehensive clamping force information is less than or equal to a preset threshold.

[0149] Optionally, the above device further comprises: a verification input module, a first abnormality determination module and a first re-execution module;

[0150] Specifically, the above-mentioned verification input module is used to input the verification caliper position information into the above-mentioned clamping force estimation model to obtain the verification clamping force corresponding to the above-mentioned verification caliper position information; the above-mentioned first abnormality judgment module is used to judge that the operation is abnormal if the difference between the actual clamping force corresponding to the above-mentioned verification caliper position information and the above-mentioned verification clamping force is greater than or equal to a first preset threshold value; the above-mentioned first re-execution module is used to re-execute the above-mentioned acquisition of the caliper initial position if the number of times the operation is judged to be abnormal is greater than a second preset threshold value.

[0151] Optionally, the above device further includes: a second abnormality determination module and a second re-execution module;

[0152] Specifically, the second abnormality determination module is used to determine that an operation is abnormal when the current positive position information or the current negative position information reaches a preset position and the motor speed fluctuation within a preset time is higher than a third preset threshold value; the second re-execution module is used to re-execute the acquisition of the caliper initial position if the number of times the operation is determined to be abnormal is greater than a fourth preset threshold value.

[0153] Optionally, the above device further includes: a third abnormality determination module and a third re-execution module;

[0154] Specifically, the third abnormality determination module is used to determine that an operation is abnormal if the absolute value of the difference between the positive torque information and the negative torque information is greater than the maximum value of all the positive torque information and the negative torque information; the third re-execution module is used to re-execute the acquisition of the caliper initial position if the number of times the operation is determined to be abnormal is greater than the fifth preset threshold.

[0155] Optionally, the current caliper position information is related to current torque data, and the current torque data is the product of the motor torque coefficient and the current q-axis current of the motor.

[0156] In summary, the present application discloses a clamping force estimation device, which can obtain the clamping force by inputting the current caliper position information of the caliper friction plate into the clamping force estimation model, avoiding the problem that the clamping force must be obtained by using an expensive and high-installation clamping force sensor in the related art, and can achieve precise control of the vehicle by the electronic mechanical brake system even when the technical cost and production cost are low. In addition, the controller can also be used to give the motor a series of stroke angles, and remove the influence of dynamic and static friction by successive and positive and negative directions, and combined with the corresponding calculation strategy, so as to achieve precise control of the vehicle by the electronic mechanical brake system.

[0157] Correspondingly, the present application also discloses a vehicle, comprising the clamping force estimation device as described in the aforementioned embodiments.

[0158] A vehicle provided in an embodiment of the present application has the beneficial effects of the clamping force estimation device introduced above.

[0159] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same and similar parts between the various embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the method and vehicle embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiments. The method and vehicle described above are merely schematic, in which the units described as separate components may or may not be physically separated, and the components indicated as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without creative work.

[0160] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A clamping force estimation method, characterized in that: The method comprises: Get the current caliper position information; The current caliper position information is input into a clamping force estimation model to obtain a clamping force corresponding to the current caliper position information.

2. The method according to claim 1, characterized in that The clamping force estimation model is constructed by the following method: Get the initial position of the caliper; In the direction of increasing the stroke, the positive torque information corresponding to the current positive position information is obtained once every preset distance, and the positive position information is the sum of the initial position of the caliper and the product of the number of acquisitions and the preset distance; in the direction of decreasing the stroke, the negative torque information corresponding to the current negative position information is obtained once every preset distance, and the negative position information is the difference between the initial position of the caliper and the product of the number of acquisitions and the preset distance; Acquire clamping force information corresponding to positive torque information and negative torque information, wherein the positive torque information and the negative torque information are torque information with equal distances from an initial position of the caliper and opposite directions; The positive torque information and the negative torque information are used as input, and the clamping force information is used as output to train a neural network model to obtain a clamping force estimation model.

3. The method according to claim 2, characterized in that The obtaining of the clamping force information corresponding to the positive torque information and the negative torque information includes: Taking the average value of the positive torque information and the negative torque information to obtain the average torque information; The product of the average torque information and the transmission ratio is divided by the equivalent radius of the ball screw of the transmission structure to obtain the clamping force information corresponding to the positive torque information and the negative torque information.

4. The method according to claim 2, characterized in that: The obtaining of the clamping force information corresponding to the positive torque information and the negative torque information includes: Taking the average value of the positive torque information and the negative torque information to obtain the average torque information; Obtaining comprehensive torque information according to the average torque information and the static friction equivalent torque information, wherein the static friction equivalent torque information is related to the output speed of the motor; Acquiring comprehensive clamping force information corresponding to the comprehensive torque information; The method of taking the positive torque information and the negative torque information as input and the clamping force information as output to train a neural network model comprises: The comprehensive torque information is used as input, and the comprehensive clamping force information is used as output to train a neural network model.

5. The method according to claim 4, characterized in that The method of taking the comprehensive torque information as input and the comprehensive clamping force information as output to train a neural network model comprises: If the magnitude of the comprehensive clamping force information is less than or equal to a preset threshold, the comprehensive torque information is used as input, and the comprehensive clamping force information is used as output to train the neural network model.

6. The method according to claim 2, characterized in that The method further comprises: Inputting the verification caliper position information into the clamping force estimation model to obtain the verification clamping force corresponding to the verification caliper position information; If the difference between the actual clamping force corresponding to the verification caliper position information and the verification clamping force is greater than or equal to a first preset threshold, it is determined that the operation is abnormal; If it is determined that the number of abnormal operations is greater than a second preset threshold, the step of obtaining the initial position of the caliper is performed again.

7. The method according to claim 2, characterized in that The method further comprises: When the current positive position information or the current negative position information reaches a preset position, if the motor speed fluctuation within a preset time is higher than a third preset threshold, it is determined that the operation is abnormal; If it is determined that the number of abnormal operations is greater than a fourth preset threshold, the step of obtaining the initial position of the caliper is performed again.

8. The method according to claim 2, characterized in that: The method further comprises: If the absolute value of the difference between the positive torque information and the negative torque information is greater than the maximum value of all the positive torque information and the negative torque information, it is determined that the operation is abnormal; If it is determined that the number of abnormal operations is greater than a fifth preset threshold, the step of obtaining the initial position of the caliper is performed again.

9. The method according to claim 1, characterized in that: The current caliper position information is related to the current torque data, and the current torque data is the product of the motor torque coefficient and the current motor q-axis current.

10. A clamping force estimation device, characterized in that: The device comprises: an information acquisition module and a model output module; The information acquisition module is used to obtain current caliper position information; The model output module is used to input the current caliper position information into the clamping force estimation model to obtain the clamping force corresponding to the current caliper position information.

11. A vehicle, characterized in that: The vehicle comprises a clamping force estimating device, which is used to perform the clamping force estimating method according to any one of claims 1-9.

Images