A method and system for matching brake pedal deceleration

Abstract

The application provides a brake pedal deceleration matching method and system, the method comprising: determining the response characteristic parameters of the pull motor according to the model of the pull motor; increasing the speed of the vehicle to be tested to above a first preset value, adjusting the pull motor stroke according to a set rule, and obtaining the running data of the vehicle to be tested; inputting the running data into a set model for data fitting to obtain fitting data; calculating the root mean square error of the fitting data, eliminating the fitting data with a root mean square error less than a second preset value from the set model to obtain an initial model; determining the initial model with the largest number of data points as a target model; and the target model is configured to determine the deceleration of the vehicle to be tested according to the pull motor stroke, so as to solve the problem that the relationship between the brake force of the brake pedal and the pull motor stroke of the current pull motor in a specific stroke is unknown, which leads to the inability to determine the deceleration of the vehicle through the pull motor stroke.

Description

Technical Field

[0001] This application relates to the field of driver assistance technology, and in particular to a brake pedal deceleration matching method and system. Background Technology

[0002] For the aftermarket vehicle market, especially for ADAS (Advanced Driver Assistance Systems) with braking functions, compatibility with the vast majority of vehicle models is required. This necessitates adaptability to different manufacturers, chassis, and braking actuators to ensure rapid installation on randomly selected vehicles. Because the braking performance of randomly installed aftermarket vehicles varies, obtaining the vehicle's braking characteristics is crucial for achieving consistent braking effects across different models. Otherwise, ensuring consistent braking performance and the stable operation of the ADAS product cannot be guaranteed.

[0003] For the aftermarket, common aftermarket braking systems include brake pedal modification. Brake pedal modifications typically use cable-operated motors, but these motors cannot control the cable travel; they only have two states: cable engaged and unengaged. This type of cable-operated motor can only be used for emergency braking in AEB (Automatic Emergency Braking) systems.

[0004] The travel of the cable motor corresponds to the free travel and full travel positions of the brake pedal. Determining these two positions completes the installation and calibration of the cable motor. However, the relationship between the braking force of the brake pedal and the travel of the cable motor is unknown during its specific travel. This makes it impossible to determine the vehicle's deceleration based on the travel of the cable motor, thus causing ADAS product functions to malfunction. Summary of the Invention

[0005] This application provides a brake pedal deceleration matching method and system to solve the technical problem that the relationship between the braking force of the brake pedal and the travel of the cable motor is unknown during the specific travel of the existing cable motor, which makes it impossible to determine the deceleration of the vehicle through the travel of the cable motor.

[0006] The first aspect of this application provides a brake pedal deceleration matching method, applied to a cable motor, wherein the cable motor is connected to the brake pedal of the vehicle under test; comprising:

[0007] Based on the model of the wire-drawing motor, determine the response characteristic parameters of the wire-drawing motor;

[0008] The vehicle speed is increased to above a first preset value, and the travel of the cable motor is adjusted according to a set rule to obtain the vehicle's operating data. The set rule is: when the vehicle's operating speed reaches a preset range, the cable length of the cable motor is adjusted according to a set length. The operating data includes: the time point of the vehicle's operation, its speed, and the travel of the cable motor. The set rule is determined by the response characteristic parameters.

[0009] The running data is input into a set model for data fitting to obtain fitted data; the set model includes: linear model, quadratic model, and cubic model.

[0010] Calculate the root mean square error of the fitted data, and remove the fitted data whose root mean square error is less than a second preset value from the set model to obtain the initial model;

[0011] The initial model with the largest number of data points in the fitted data is determined as the target model; the target model is configured to determine the deceleration of the vehicle under test based on the stroke of the cable motor.

[0012] In some embodiments, the response characteristic parameters include: the response delay parameter, minimum stroke parameter, maximum stroke parameter, and minimum control step size of the wire motor.

[0013] In some embodiments, the step of increasing the speed of the vehicle under test to above a first preset value, adjusting the stroke of the cable motor according to a set rule, and obtaining the operating data of the vehicle under test includes:

[0014] Increase the speed of the vehicle under test to a first preset value or higher. When the speed of the vehicle under test reaches the first preset range, reduce the cable length of the cable motor according to a set length to obtain the first operating data of the vehicle under test.

[0015] When the running speed of the vehicle under test reaches the second preset range, the cable length of the cable motor is reduced according to the set length to obtain the second running data of the vehicle under test;

[0016] When the running speed of the vehicle under test reaches the third preset range, the cable length of the cable motor is reduced according to the set length to obtain the third running data of the vehicle under test;

[0017] When the running speed of the vehicle under test reaches the fourth preset range, the pull length of the pull motor is reduced according to the set length to obtain the fourth running data of the vehicle under test;

[0018] When the running speed of the vehicle under test reaches the fifth preset range, the cable length of the cable motor is reduced according to the set length to obtain the fifth running data of the vehicle under test;

[0019] When the running speed of the vehicle under test reaches the sixth preset range, the cable length of the cable motor is reduced by a set length until the running speed of the vehicle under test drops to 0 km / h, and the sixth running data of the vehicle under test is obtained.

[0020] The first, second, third, fourth, fifth, and sixth operating data are integrated to obtain the operating data of the vehicle under test.

[0021] In some embodiments, prior to the step of inputting the running data into a set model for data fitting, the method includes:

[0022] Based on the operating data, calculate the average deceleration of the vehicle under test when its operating speed is within each preset range;

[0023] Determine whether the average deceleration is greater than a third preset value; if not, increase the value of the set length.

[0024] In some embodiments, prior to the step of inputting the running data into a set model for data fitting, the method further includes:

[0025] Based on the operating data, calculate the average deceleration of the vehicle under test when its operating speed is within each preset range;

[0026] Determine whether the average deceleration is consistent. If so, remove the corresponding operating data of the vehicle under test and increase the value of the preset range.

[0027] In some embodiments, prior to the step of inputting the running data into a set model for data fitting, the method further includes:

[0028] Based on the operating data, obtain the operating speed data of the vehicle under test when its operating speed is within each preset range;

[0029] Based on the operating speed data, determine whether the operating speed of the vehicle under test is decreasing according to a constant value;

[0030] If not, the running speed data corresponding to the preset range will be removed, and the set length value corresponding to the preset range will be re-determined.

[0031] In some embodiments, the value of the set length is determined by the effective stroke of the wire drawing motor, wherein the effective stroke is the difference between the maximum stroke parameter and the minimum stroke parameter of the wire drawing motor;

[0032] Before the step of inputting the running data into the set model for data fitting, the method further includes:

[0033] If the maximum stroke parameter of the pull-wire motor is inconsistent with the actual maximum stroke parameter, the value of the set length shall be reset according to the actual maximum stroke parameter.

[0034] In some embodiments, the step of inputting the running data into a set model for data fitting includes:

[0035] Based on the operating data, calculate the deceleration data of the vehicle under test;

[0036] The data points in the deceleration data are sorted to determine the maximum deceleration of the vehicle under test;

[0037] Based on the maximum deceleration, a preset data point is determined; the deceleration value corresponding to the preset data point is greater than the maximum deceleration.

[0038] The preset data points and the running data are input into the set model for data fitting.

[0039] In some embodiments, before the step of determining the initial model with the largest number of data points in the fitted data as the target model, the following steps are included:

[0040] Based on the initial model, the steps of calculating the root mean square error of the fitted data and removing fitted data with a root mean square error less than a second preset value from the set model are repeated until the root mean square error of the fitted data in the initial model is greater than a fourth preset value.

[0041] A second aspect of this application provides a brake pedal deceleration matching system applied to a cable motor, the cable motor being connected to the brake pedal of a vehicle under test; comprising:

[0042] The acquisition module is configured as follows:

[0043] Based on the model of the draw wire motor, determine the response characteristic parameters of the draw wire motor; the response characteristic parameters include: the response delay parameter, minimum stroke parameter, maximum stroke parameter, and minimum control step size of the draw wire motor;

[0044] Experimental module, the experimental module is configured as follows:

[0045] The vehicle speed is increased to above a first preset value, and the travel of the cable motor is adjusted according to a set rule to obtain the vehicle's operating data. The set rule is: when the vehicle's operating speed reaches a preset range, the cable length of the cable motor is adjusted according to a set length. The operating data includes: the time point of the vehicle's operation, its speed, and the travel of the cable motor. The set rule is determined by the response characteristic parameters.

[0046] The fitting module is configured as follows:

[0047] The running data is input into a set model for data fitting to obtain fitted data; the set model includes: linear model, quadratic model, and cubic model.

[0048] Calculate the root mean square error of the fitted data, and remove the fitted data whose root mean square error is less than a second preset value from the set model to obtain the initial model;

[0049] The initial model with the largest number of data points in the fitted data is determined as the target model; the target model is configured to determine the deceleration of the vehicle under test based on the stroke of the cable motor.

[0050] This application provides a brake pedal deceleration matching method and system, applied to a cable motor connected to the brake pedal of a vehicle under test. The method includes: determining the response characteristic parameters of the cable motor based on its model; increasing the speed of the vehicle under test to above a first preset value; adjusting the stroke of the cable motor according to a set rule; and acquiring the operating data of the vehicle under test. The set rule is: when the operating speed of the vehicle under test reaches a preset range, adjusting the cable length of the cable motor according to a set length. The operating data includes: the time point of operation of the vehicle under test, its speed, and the stroke of the cable motor. The set rule is determined by the response characteristic parameters. The parameters are determined; the running data is input into a set model for data fitting to obtain fitted data; the set model includes: linear model, quadratic model, and cubic model; the root mean square error of the fitted data is calculated, and fitted data with a root mean square error less than a second preset value are removed from the set model to obtain an initial model; the initial model with the largest number of data points of the fitted data is determined as the target model; the target model is configured to determine the deceleration of the vehicle under test based on the travel of the cable motor, so that the cable motor can clearly define the relationship between the braking force of the brake pedal and the travel of the cable motor in a specific travel, thereby determining the deceleration of the vehicle through the travel of the cable motor. Attached Figure Description

[0051] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This is a flowchart of the brake pedal deceleration matching method in this application;

[0053] Figure 2 This is a flowchart illustrating the deceleration of the vehicle specified in this application;

[0054] Figure 3 This is a schematic diagram of the structure when the low-end wire-driven motor is braking.

[0055] Figure 4 This is a schematic diagram of the structure of a high-precision wire-drawing motor during braking.

[0056] Figure 5 This is a schematic diagram showing the relationship between the effective stroke percentage of the cable motor and the vehicle speed in this application.

[0057] Figure 6 This is a schematic diagram of the fitting curve in one embodiment of this application;

[0058] Figure 7 This is a schematic diagram of the fitting curve in another embodiment of this application. Detailed Implementation

[0059] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0060] For example, this application only discusses the application of aftermarket ADAS (Advanced Driver Assistance Systems). In the OEM market, all information in the vehicle's CAN (Central Network System) bus is made available to the ADAS domain controller. This includes the control of the braking system and the characteristics of the braking system, which are provided to the matching ADAS controller before the vehicle is mass-produced. Therefore, OEM ADAS products are customized for each vehicle. Each model, and even different configurations of the same model, require independent debugging and adaptation. In particular, ADAS products with braking functions must be adapted to the braking characteristics of the corresponding model for a period of time. After passing the acceptance test, they can be mass-produced with the vehicle.

[0061] For the aftermarket, especially ADAS functions with braking capabilities, compatibility with the vast majority of vehicle models is required. This necessitates adapting to different manufacturers, chassis, and braking actuators to ensure quick installation on randomly selected vehicles. However, this raises a problem: the braking performance of randomly installed aftermarket vehicles varies greatly. To achieve nearly consistent braking effects across different vehicle models, it is essential to obtain the vehicle's braking characteristics. Otherwise, ensuring consistent braking performance is difficult, and the stable operation of ADAS products becomes impossible.

[0062] Regarding aftermarket issues, there are currently many common aftermarket braking system solutions: air circuit modification to control the brake air circuit (only for air brake models), and brake pedal modification (for all vehicle models). Air circuit modification can use proportional control valves, solenoid valves, etc., while brake pedal modification generally uses a cable-operated motor, such as... Figure 3 As shown.

[0063] There are various types of pull-wire motors. Low-end pull-wire motors cannot control the pull-wire stroke and only have two states: pull-wire and no pull-wire. This type of pull-wire motor can only be used for AEB (Automatic Emergency Braking) emergency braking. The following specifications need to be calibrated when installing this type of motor: 1. Ensure that the pull-wire motor can pull the pedal all the way down; 2. Ensure that the pedal is in a relaxed state when the pull-wire motor is not pulling the cord.

[0064] For high-precision stroke control motors, more refined control is possible, which places higher demands on installation and calibration. Based on actual application scenarios, the calibration requirements for cable-operated motors are: the calibration results must be used for both passive ACC (Adaptive Cruise Control) easing braking and AEB (Automatic Emergency Braking) braking. Therefore, the force calibration results in both the short and long stroke stages must be accurate. Otherwise, both functions cannot operate normally simultaneously. However, in general, common calibration schemes are more often used for AEB braking calibration. The specific method is as follows: First step: Install the cable-operated motor, ensuring it does not interfere with the driver's braking and conforms to installation specifications; Second step: Control the cable-operated motor to pull the cable until the brake light illuminates, and mark this stroke position (L1). Figure 4 As shown; Step 3: Control the cable motor to pull the brake pedal all the way down, and record the travel position (L2), as shown. Figure 4 As shown.

[0065] At this point, the obtained cable motor travel (L1 and L2) corresponds to the idle and full travel positions of the brake pedal, respectively. Determining these two positions completes the installation calibration of the cable motor. The relationship between braking force and travel during the specific travel is unknown. Therefore, this calibration scheme poses a significant challenge to the motor control algorithm. However, this is not a major issue for AEB (because AEB is generally only triggered in very urgent scenarios, and the pedal is usually pulled all the way to the bottom, so there is no need to pay attention to the specific relationship between travel and braking force). However, for passive ACC (Adaptive Cruise Control) and other mild braking scenarios, if the relationship between travel and braking is unknown, it can only be assumed to be a linear relationship for control. During the control process, negative feedback control logic needs to be added to adjust the control results in real time. However, for the passive triggering function of ADAS products, each time the ADAS product triggers the braking function, it represents a dangerous driving incident. Therefore, by adopting a refined calibration process and a precise calibration method for braking performance, it is possible to quickly calibrate the braking performance of different vehicles on-site, providing a good basic reference for ADAS braking control.

[0066] In some technologies, the relationship between the braking force of the brake pedal and the travel of the cable motor during its specific stroke is unknown, making it impossible to determine the vehicle deceleration based on the cable motor travel. To address this technical problem, this application provides a brake pedal deceleration matching method and system, which are described below:

[0067] like Figure 1 The diagram shown is a flowchart of the brake pedal deceleration matching method in this application.

[0068] The first aspect of this application provides a brake pedal deceleration matching method, applied to a cable motor, wherein the cable motor is connected to the brake pedal of the vehicle under test; comprising the following steps:

[0069] S100: Determine the response characteristic parameters of the cable motor according to its model. These parameters include: the response delay parameter, minimum travel parameter, maximum travel parameter, and minimum control step size. The response delay parameter refers to the brake pedal free travel (also known as the brake pedal idle travel), which is the travel distance before the braking system generates braking force during the braking process of pressing the brake pedal. Specifically, it is the distance from the initial position of the pedal to the point where the brake master cylinder piston begins to generate braking force. This travel is mainly used to eliminate mechanical clearances within the braking system, such as the clearance between the brake master cylinder piston and the cylinder body, and the clearance between the brake pedal and the booster. In other words, it is the cable length of the cable motor from its initial position to before the braking system generates braking force. The minimum travel parameter and the maximum travel parameter are determined by the cable motor travel, which refers to the distance by which the cable length decreases from the initial position of the cable motor. The minimum travel parameter is the cable length at the initial position of the cable motor, and the maximum travel parameter is the cable length at its maximum value. The minimum control step size is the cable length corresponding to the change in braking force generated by the braking system.

[0070] like Figure 2 The diagram shown is a flowchart for determining the vehicle deceleration in this application.

[0071] S200: Increase the speed of the vehicle under test to above a first preset value, adjust the travel of the cable-operated motor according to a set rule, and acquire the operating data of the vehicle under test; the set rule is: when the operating speed of the vehicle under test reaches a preset range, adjust the cable length of the cable-operated motor according to a set length; the operating data includes: the time point of the vehicle under test's operation, the vehicle speed, and the travel of the cable-operated motor; the set rule is determined by the response characteristic parameters; first, on a flat surface, increase the vehicle speed to greater than 60 km / h. When the system detects that the vehicle speed is greater than 60 km / h, it enters the calibration state. It checks whether both the brake pedal and accelerator pedal are in the initial position. If so, when the vehicle speed is less than 60 km / h, the cable-operated motor starts pulling the cable.

[0072] The step of increasing the speed of the vehicle under test to above a first preset value, adjusting the stroke of the cable motor according to a set rule, and obtaining the operating data of the vehicle under test includes the following sub-steps:

[0073] S210: Increase the speed of the vehicle under test to above a first preset value. When the speed of the vehicle under test reaches the first preset range, reduce the cable length of the cable motor by a set length to obtain the first operating data of the vehicle under test. The set length is one-sixth of the maximum effective stroke of the cable motor; the first preset value is 60 km / h; the first preset range is 55-60 km / h.

[0074] S220: When the operating speed of the vehicle under test reaches a second preset range, the cable length of the cable motor is reduced by a set length to obtain the second operating data of the vehicle under test. The second preset range is 45-55 km / h.

[0075] S230: When the operating speed of the vehicle under test reaches a third preset range, the cable length of the cable motor is reduced by a set length to obtain the third operating data of the vehicle under test. The third preset range is 35-45 km / h.

[0076] S240: When the operating speed of the vehicle under test reaches the fourth preset range, the cable length of the cable motor is reduced according to a set length to obtain the fourth operating data of the vehicle under test. The fourth preset range is 25-35 km / h.

[0077] S250: When the operating speed of the vehicle under test reaches the fifth preset range, the cable length of the cable motor is reduced according to a set length to obtain the fifth operating data of the vehicle under test. The fifth preset range is 15-25 km / h.

[0078] S260: When the operating speed of the vehicle under test reaches the sixth preset range, the cable length of the cable motor is reduced by a set length until the operating speed of the vehicle under test drops to 0 km / h, and the sixth operating data of the vehicle under test is obtained. The fifth preset range is 0 to 15 km / h.

[0079] S270: Integrate the first operating data, the second operating data, the third operating data, the fourth operating data, the fifth operating data, and the sixth operating data to obtain the operating data of the vehicle under test.

[0080] Specifically, the pull-wire motor pulls the wire according to the following logic:

[0081] Table 1: Relationship between vehicle speed range and the proportion of the cable motor stroke to the maximum effective stroke.

[0082] Speed ​​range The proportion of the wire motor's stroke to its maximum effective stroke 55~60km / h 1 / 6 45~55km / h 2 / 6 35~45km / h 3 / 6 25~35km / h 4 / 6 15~25km / h 5 / 6 0~15km / h 6 / 6

[0083] The vehicle speed curve of the test vehicle under the ratio of the cable motor stroke to the maximum effective stroke is shown in the figure below. Figure 5 As shown.

[0084] The data format for the vehicle's operation during braking is as follows:

[0085] Table 2: Vehicle Operation Data Table

[0086] Time (ms) Wire pull motor stroke (mm) Vehicle speed (km / h) ***** ***** *****

[0087] S300: The running data is input into a set model for data fitting to obtain fitted data; the set model includes: a linear model, a quadratic model, and a cubic model. By setting multiple set models simultaneously for fitting, and through a designed method for selecting the optimal model, the deceleration of the target model calibrated vehicle is obtained.

[0088] In this embodiment, before the step of inputting the running data into the set model for data fitting, the following steps are included:

[0089] Based on the operating data, calculate the average deceleration of the vehicle under test when its operating speed is within each preset range; determine whether the average deceleration is greater than a third preset value; if not, increase the value of the set length.

[0090] Specifically, based on the aforementioned operational data, the average deceleration of the vehicle under test at each stage is calculated, and the maximum deceleration value is checked to see if it exceeds 6 m / s². 2 If the maximum average deceleration is less than 6 m / s 2 This is achieved by increasing the overall proportion of the maximum effective stroke, i.e., increasing the value of the set length. The specific multiplier is designed and adjusted based on practical experience. For example, the proportion of the wire pull motor stroke to the maximum effective stroke can be adjusted from 1 / 6 to 1 / 5.

[0091] In this embodiment, before the step of inputting the running data into the set model for data fitting, the following steps are also included:

[0092] Based on the operating data, calculate the average deceleration of the vehicle under test when its operating speed is within each preset range; determine whether the average deceleration is consistent; if so, remove the corresponding operating data of the vehicle under test and increase the value of the preset range.

[0093] Specifically, by checking whether the average deceleration of the vehicle is too concentrated in each stage, such as whether the average deceleration of the vehicle is consistent in each stage, if the average deceleration is too concentrated, the data is removed and the braking speed range of that stage is expanded. For example, the speed ranges of 35-45 km / h and 25-35 km / h are merged into 25-45 km / h.

[0094] In this embodiment, before the step of inputting the running data into the set model for data fitting, the following steps are also included:

[0095] Based on the operating data, obtain the operating speed data of the vehicle under test when its operating speed is within each preset range; based on the operating speed data, determine whether the operating speed of the vehicle under test is reduced according to a constant value; if not, remove the operating speed data corresponding to the preset range, and redetermine the set length value corresponding to the preset range.

[0096] Specifically, the smoothness of the vehicle speed change is checked, i.e., whether the operating speed of the vehicle under test decreases at a constant value. If the speed change is not smooth, the average deceleration data for the corresponding braking phase is discarded, and the cable travel in that speed range is adjusted. For example, the ratio of the cable motor travel to the maximum effective travel is adjusted from 1 / 6 to 1 / 5.

[0097] In this embodiment, the value of the set length is determined by the effective stroke of the wire drawing motor, which is the difference between the maximum stroke parameter and the minimum stroke parameter of the wire drawing motor. Effective stroke of the wire drawing motor = Maximum stroke parameter of the wire drawing motor - Minimum stroke parameter of the wire drawing motor.

[0098] Before the step of inputting the running data into the set model for data fitting, the following steps are also included:

[0099] If the maximum stroke parameter of the cable-operated motor is inconsistent with the actual maximum stroke parameter, the set length value is reset according to the actual maximum stroke parameter. It is understood that the maximum stroke parameter is determined based on the cable-operated motor model. However, due to aftermarket installations, the maximum stroke parameter of the cable-operated motor may change due to factors such as service life. During the acquisition of the operating data of the vehicle under test, it may be found that the maximum stroke parameter of the cable-operated motor is inconsistent with the maximum stroke parameter determined by the cable-operated motor model. Therefore, to ensure the accuracy of the operating data, it is necessary to change the maximum stroke parameter of the cable-operated motor, and then redetermine the cable length of the cable-operated motor based on the proportion of the cable-operated motor stroke to the maximum effective stroke.

[0100] The step of inputting the running data into the set model for data fitting includes the following sub-steps:

[0101] S310: Calculate the deceleration data of the vehicle under test based on the operating data; S310: Sort the data points in the deceleration data to determine the maximum deceleration of the vehicle under test; S330: Determine a preset data point based on the maximum deceleration; the deceleration value corresponding to the preset data point is greater than the maximum deceleration; S340: Input the preset data point and the operating data together into a set model for data fitting.

[0102] In this embodiment, by adding a preset data point, it is ensured that the fitting result is monotonically increasing at the end, thereby making the fitting result more consistent with the characteristics of the actual brake (although the brake pedal is fully depressed, continued deep braking can maintain braking force to a certain extent, but once the brake pedal is released, the braking force will change; if the brake pedal is released, the data point at the end of the fitting curve will not be at the highest value, such as...). Figure 6 As shown, training the model according to the above fitted curve will lead to incomplete braking of the test vehicle when running according to the trained model. Therefore, the data points at the end of the fitting result must be monotonically increasing to ensure braking stability. The specific fitted curve is shown in Figure 1. Figure 7 (as shown), thereby improving the accuracy of the calibration results.

[0103] S400: Calculate the root mean square error of the fitted data, and remove the fitted data whose root mean square error is less than a second preset value from the set model to obtain the initial model.

[0104] Specifically, the root mean square error of the fitted data is calculated. If the root mean square error is less than 0.8, outliers are removed from the initial model to obtain the initial model.

[0105] S500: The initial model with the largest number of data points in the fitted data is determined as the target model; the target model is configured to determine the deceleration of the vehicle under test based on the stroke of the pull-wire motor.

[0106] Before the step of determining the initial model with the largest number of data points in the fitted data as the target model, the following steps are included:

[0107] Based on the initial model, the steps of calculating the root mean square error of the fitted data and removing fitted data with a root mean square error less than a second preset value from the set model are repeated until the root mean square error of the fitted data in the initial model is greater than a fourth preset value.

[0108] Specifically, the root mean square error (RMSE) of the fitted data is calculated. If the RMSE is less than 0.8, outliers are removed from the initial model, and the fitting process continues. Finally, the model with the RMSE greater than 0.9 and retaining the most valid data is selected as the best-matching model, i.e., the target model. The ADAS system can achieve better braking control for the vehicle under test using this target model.

[0109] A second aspect of this application provides a brake pedal deceleration matching system applied to a cable motor, the cable motor being connected to the brake pedal of a vehicle under test; comprising:

[0110] The acquisition module is configured as follows:

[0111] Based on the model of the draw wire motor, determine the response characteristic parameters of the draw wire motor; the response characteristic parameters include: the response delay parameter, minimum stroke parameter, maximum stroke parameter, and minimum control step size of the draw wire motor;

[0112] Experimental module, the experimental module is configured as follows:

[0113] The vehicle speed is increased to above a first preset value, and the travel of the cable motor is adjusted according to a set rule to obtain the vehicle's operating data. The set rule is: when the vehicle's operating speed reaches a preset range, the cable length of the cable motor is adjusted according to a set length. The operating data includes: the time point of the vehicle's operation, its speed, and the travel of the cable motor. The set rule is determined by the response characteristic parameters.

[0114] The fitting module is configured as follows:

[0115] The running data is input into a set model for data fitting to obtain fitted data; the set model includes: linear model, quadratic model, and cubic model.

[0116] Calculate the root mean square error of the fitted data, and remove the fitted data whose root mean square error is less than a second preset value from the set model to obtain the initial model;

[0117] The initial model with the largest number of data points in the fitted data is determined as the target model; the target model is configured to determine the deceleration of the vehicle under test based on the stroke of the cable motor.

[0118] It is worth noting that the effects of the above system embodiments can be found in the effects of the above method embodiments, and will not be repeated here.

[0119] The above detailed embodiments further illustrate the purpose, technical solution, and beneficial effects of the embodiments of this application. It should be understood that the above are merely specific embodiments of the embodiments of this application and are not intended to limit the protection scope of the embodiments of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solutions of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A brake pedal deceleration matching method applied to a pull wire motor connected to a brake pedal of a vehicle to be tested, characterized in that, The method comprises the following steps: determining a response characteristic parameter of the pull motor according to a model of the pull motor; increasing the speed of the vehicle to be tested to a first preset value or above, adjusting the stroke of the pull motor according to a set rule, and obtaining the running data of the vehicle to be tested; the set rule is that when the running speed of the vehicle to be tested reaches a preset range, the length of the pull wire of the pull motor is adjusted according to a set length; the running data comprises the time point, speed and stroke of the pull motor when the vehicle to be tested is running; the set rule is determined by the response characteristic parameter; inputting the running data into a set model for data fitting to obtain fitting data; the set model comprises a linear model, a quadratic model and a cubic model; calculating the root mean square error of the fitting data, removing the fitting data with a root mean square error less than a second preset value from the set model, and obtaining an initial model; determining the initial model with the largest number of data points as a target model; the target model is configured to determine the deceleration of the vehicle to be tested according to the stroke of the pull motor.

2. The brake pedal de-acceleration matching method of claim 1, wherein, The response characteristic parameter comprises a response delay parameter, a minimum stroke parameter, a maximum stroke parameter and a minimum control step length of the pull motor.

3. The brake pedal de-acceleration matching method of claim 1, wherein, The step of increasing the speed of the vehicle to be tested to a first preset value or above, adjusting the stroke of the pull motor according to a set rule, and obtaining the running data of the vehicle to be tested comprises: increasing the speed of the vehicle to be tested to a first preset value or above, decreasing the length of the pull wire of the pull motor according to a set length when the running speed of the vehicle to be tested reaches a first preset range, and obtaining first running data of the vehicle to be tested; decreasing the length of the pull wire of the pull motor according to a set length when the running speed of the vehicle to be tested reaches a second preset range, and obtaining second running data of the vehicle to be tested; decreasing the length of the pull wire of the pull motor according to a set length when the running speed of the vehicle to be tested reaches a third preset range, and obtaining third running data of the vehicle to be tested; decreasing the length of the pull wire of the pull motor according to a set length when the running speed of the vehicle to be tested reaches a fourth preset range, and obtaining fourth running data of the vehicle to be tested; decreasing the length of the pull wire of the pull motor according to a set length when the running speed of the vehicle to be tested reaches a fifth preset range, and obtaining fifth running data of the vehicle to be tested; decreasing the length of the pull wire of the pull motor according to a set length when the running speed of the vehicle to be tested reaches a sixth preset range, and obtaining sixth running data of the vehicle to be tested until the running speed of the vehicle to be tested decreases to 0 km / h; integrating the first running data, the second running data, the third running data, the fourth running data, the fifth running data and the sixth running data to obtain the running data of the vehicle to be tested.

4. The brake pedal fade mitigation method of claim 1, wherein, Before the step of inputting the running data into a set model for data fitting, the method comprises the following steps: calculating the average deceleration of the vehicle to be tested when the running speed of the vehicle to be tested is in each preset range according to the running data; determining whether the average deceleration is greater than a third preset value, and if not, increasing the value of the set length.

5. The brake pedal de-acceleration matching method of claim 1, wherein, Before the step of inputting the running data into the set model for data fitting, the method further comprises: According to the running data, the average deceleration of the vehicle under test when the running speed is within each preset range is calculated. If the average deceleration is consistent, the running data of the vehicle under test corresponding to the preset range is removed, and the value of the preset range is increased.

6. The brake pedal de-acceleration matching method of claim 1, wherein, Before the step of inputting the running data into the set model for data fitting, the method further comprises: According to the running data, the running speed data when the running speed of the vehicle under test is within each preset range is obtained. According to the running speed data, it is determined whether the running speed of the vehicle under test decreases according to a constant value. If not, the running speed data corresponding to the preset range is removed, and the value of the set length within the preset range is re-determined.

7. The brake pedal de-acceleration matching method of claim 2, wherein, The value of the set length is determined by the effective stroke of the pull motor, and the effective stroke is the difference between the maximum stroke parameter and the minimum stroke parameter of the pull motor. Before the step of inputting the running data into the set model for data fitting, the method further comprises: If the maximum stroke parameter of the pull motor is inconsistent with the actual maximum stroke parameter, the value of the set length is re-set according to the actual maximum stroke parameter.

8. The brake pedal de-acceleration matching method of claim 1, wherein, The step of inputting the running data into the set model for data fitting comprises: According to the running data, the deceleration data of the vehicle under test is calculated. The data points in the deceleration data are sorted to determine the maximum deceleration of the vehicle under test. According to the maximum deceleration, a preset data point is determined; the deceleration value corresponding to the preset data point is greater than the maximum deceleration. The preset data point and the running data are input into the set model for data fitting.

9. The brake pedal de-acceleration matching method of claim 1, wherein, Before the step of determining the initial model with the largest number of data points of the fitting data as the target model, the method comprises: Based on the initial model, the steps of calculating the root mean square error of the fitting data and removing the fitting data with a root mean square error less than a second preset value from the set model are repeatedly performed until the root mean square error of the fitting data in the initial model is greater than a fourth preset value.

10. A brake pedal deceleration matching system applied to a pull wire motor connected to a brake pedal of a vehicle to be tested, characterized in that, Comprise: The acquisition module is configured to: According to the model of the pull motor, the response characteristic parameters of the pull motor are determined; the response characteristic parameters include: response delay parameters, minimum stroke parameters, maximum stroke parameters, and minimum control step lengths of the pull motor. The experimental module is configured to: The vehicle speed of the vehicle to be tested is increased to a first preset value, the cable motor stroke is adjusted according to a set rule, and the running data of the vehicle to be tested is obtained; the set rule is that when the running speed of the vehicle to be tested reaches a preset range, the cable length of the cable motor is adjusted according to a set length; the running data includes the time point, the vehicle speed and the cable motor stroke when the vehicle to be tested runs; the set rule is determined by the response characteristic parameter; a fitting module configured to: input the running data into a set model for data fitting to obtain fitting data; the set model includes a linear model, a quadratic model and a cubic model; calculate the root mean square error of the fitting data, remove the fitting data with a root mean square error less than a second preset value from the set model, and obtain an initial model; determine the initial model with the largest number of data points as a target model; the target model is configured to determine the deceleration of the vehicle to be tested according to the cable motor stroke.

Images