A pedal map generation method considering driver's acceleration habits

Abstract

The present invention is applicable to the technical field of pedal map generation of electric vehicles, and provides a pedal map generation method considering the acceleration habits of a driver. The method can form a driver's commonly used acceleration area according to the collected longitudinal motion data of the driver, and generate a pedal map considering the driver's acceleration habits based on the driver's commonly used acceleration area, thereby ensuring that the pedal map reaches the driver's commonly used acceleration at the vehicle speed in the driver's commonly used pedal range, and can more accurately characterize the driver's acceleration habits, thereby achieving the purpose of adaptively adapting to the driver's acceleration habits.

Description

Technical Field

[0001] The invention belongs to the technical field of electric vehicle pedal map generation, and in particular relates to a pedal map generation method taking into account a driver's acceleration habits. Background Art

[0002] In the process of automobile electrification and intelligence, the automobile chassis has undergone a technological transformation from mechanical chassis to electric chassis and then to intelligent chassis. The throttle system has evolved from a mechanical throttle system to a wire-controlled throttle system, which can meet the driver's desired movement by configuring a pedal map. Unlike fuel vehicles, the throttle system of electric vehicles controls the motor torque to achieve vehicle acceleration and deceleration. In addition, the electric vehicle motor has a fast power response and can quickly meet the driver's driving needs. In order to meet the acceleration needs of diverse drivers, compared with the relatively single driving mode of fuel vehicles, electric vehicles have designed different pedal maps based on diverse driving modes, and drivers can choose different driving modes according to their own acceleration habits.

[0003] Current research mainly sets multiple pedal maps based on driving modes to meet the needs of drivers' acceleration habits. This method has the following limitations:

[0004] First, there are few types of acceleration modes that drivers can choose from, which are generally divided into three acceleration modes: economy, comfort, and sports. Drivers can only choose preset acceleration modes to approximately meet their own acceleration needs. Secondly, most of the current electric vehicle pedal maps are torque-based pedal maps, that is, the input is the driver's accelerator pedal opening, and the output is the motor's required torque. In addition, the current electric vehicle pedal maps are mostly designed based on the external characteristics of the electric vehicle drive motor, which can interpret the driver's intention as the required torque of the drive motor, but the motor drive torque cannot represent the driver's desired movement and can only indirectly and passively reflect the driver's acceleration needs; finally, there is currently little research on the generation of acceleration-based pedal maps, and research on the generation of pedal maps that consider the driver's acceleration habits is basically blank. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a pedal map generation method that takes into account the acceleration habits of the driver, aiming to solve the problems raised in the above-mentioned background technology.

[0006] The embodiment of the present invention is implemented as follows: a pedal map generation method considering the driver's acceleration habits includes the following specific steps:

[0007] Step 1: Collect real-time speed through vehicle sensors With acceleration , after the driver has driven for a period of time, the driver's acceleration and speed data set is obtained for subsequent data analysis;

[0008] Step 2: Use the multivariate kernel density estimation method to estimate the acceleration in the acceleration and velocity data set obtained in step 1 and speed The probability density of binary variables is estimated. The specific formula of binary kernel density estimation is as follows:

[0009] ;

[0010] In the formula, For at point x The kernel density estimate at n is the sample size, h is the bandwidth, K is the kernel function, is the sample point;

[0011] In the probability density of the binary variables acceleration and velocity Finally, the polygon fitting method is used to fit the driver's acceleration-speed distribution characteristic envelope into a rhombus, and then the boundary of the driver's comfortable acceleration area is obtained. The boundary expression of the driver's comfortable area is as follows:

[0012] ;

[0013] In the formula, To stabilize the vehicle speed; Acceleration for driver comfort; f is the mapping relationship between the two;

[0014] Step 3: After obtaining the boundary of the driver's comfortable acceleration zone, design the accelerator pedal opening and the vehicle's stable speed The mapping relationship between the pedal opening and the driver's comfortable acceleration is as follows:

[0015] ;

[0016] In the formula, is the accelerator pedal opening; Acceleration for driver comfort, F The mapping relationship between the two.

[0017] Step 4: Divide the pedal map into a comfortable acceleration zone and a limit acceleration zone; based on the driver's comfortable acceleration zone obtained in step 2, calculate the speed at the intersection of the boundary of the comfortable acceleration zone and the horizontal axis. As the critical speed between the comfortable acceleration zone and the extreme acceleration zone, when the speed is greater than The driver no longer expects acceleration and will only accelerate under extreme conditions and without reaching the vehicle's performance limit.

[0018] Based on the mapping relationship between the accelerator pedal opening and the vehicle stable speed, the critical speed Mapped to critical pedal opening , and can also stabilize the vehicle speed within the driver's comfortable acceleration zone boundary Corresponding maximum comfortable acceleration Converted into accelerator pedal opening The corresponding comfortable acceleration;

[0019] Step 5: Based on the obtained critical pedal opening At the same time, the vehicle's limit acceleration at a certain stable speed is obtained based on the vehicle's overall parameters, and then converted into the vehicle's limit acceleration corresponding to a certain pedal opening ;

[0020] Step 6: Based on the feature points obtained in the above steps, a logarithmic function is used to generate a pedal map of the comfortable acceleration zone. The specific expression formula is as follows:

[0021] ;

[0022] In the formula, The acceleration expected by the driver; is the coefficient of the logarithmic function, which can be determined by the driver's comfortable acceleration , and accelerator pedal opening Critical pedal opening obtain; among them Critical pedal opening Accelerator pedal opening difference; C is the acceleration constant;

[0023] For the generation of pedal map in the extreme acceleration zone, an exponential function is used to express it. The specific expression is as follows:

[0024] ;

[0025] In the formula, The acceleration expected by the driver; is the coefficient of the exponential function, which can be obtained from the vehicle performance limit acceleration , and accelerator pedal opening Critical pedal opening obtain; among them is the critical pedal opening; is the accelerator pedal opening; Cis the acceleration constant;

[0026] Step 7: The final pedal map is obtained by combining the above exponential function and logarithmic function expressions. In addition, the driver's driving data can be updated online in real time. When the driver feels that the pedal map is too aggressive or conservative, the driver will have a smaller or larger acceleration distribution at this speed, so that when the next window is updated, the comfortable acceleration will iteratively become smaller or larger, thereby achieving the purpose of adaptive driver in the pedal map generation process.

[0027] A further technical solution is that in step 2, the vehicle driving resistance is calculated by the vehicle frontal area and the vehicle rolling resistance coefficient. , the specific formula is as follows (this embodiment considers driving on a flat road, so the slope resistance is not considered):

[0028] ;

[0029] In the formula, G is the gross weight of the vehicle, f is the rolling resistance coefficient, is the air resistance coefficient, A is the frontal area of ​​the vehicle, To stabilize the vehicle speed.

[0030] Based on vehicle driving resistance , and then according to the external characteristic curve of the motor, the vehicle's limit acceleration can be obtained. The calculation formula of the vehicle's limit acceleration is as follows:

[0031] ;

[0032] In the formula, is the external characteristic curve of the motor at a certain speed, m is the vehicle mass, i is the main reducer speed ratio, r is the tire rolling radius, is the vehicle's limit acceleration at a certain stable speed, is the total driving force of the vehicle.

[0033] A further technical solution is that in step 3, after obtaining the maximum vehicle speed, the minimum vehicle speed is taken as =5km / h; Taking into account the predictability of the driver's speed, the pedal stability value and speed are linearly distributed, and the relationship between the driver's pedal opening and the stable vehicle speed can be obtained, as follows:

[0034] ;

[0035] In the formula, To stabilize the vehicle speed, is the minimum stable speed, is the maximum speed, is the accelerator pedal opening.

[0036] An embodiment of the present invention provides a pedal map generation method that takes into account a driver's acceleration habits. The method can form a driver's commonly used acceleration area based on the collected driver's longitudinal motion data, and generate a pedal map that takes into account the driver's acceleration habits based on the driver's commonly used acceleration area, thereby ensuring that the pedal map reaches the driver's commonly used acceleration at the vehicle speed in the driver's commonly used pedal range, and can more accurately characterize the driver's acceleration habits, thereby achieving the purpose of adaptively adapting to the driver's acceleration habits. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A functional architecture diagram of a pedal map generation method considering a driver's acceleration habits provided by an embodiment of the present invention;

[0038] Figure 2 A flowchart of a pedal map generation method considering a driver's acceleration habits provided by an embodiment of the present invention;

[0039] Figure 3 is the driver's acceleration distribution characteristic;

[0040] Figure 4 It is the mapping relationship between the comfortable acceleration envelope and the acceleration corresponding to the critical speed;

[0041] Figure 5 This is a schematic diagram of the pedal map modeling method;

[0042] Figure 6 Pedal map for drivers with less comfortable acceleration;

[0043] Figure 7 Pedal map for drivers who want greater comfort acceleration. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0045] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0046] An embodiment of the present invention provides a pedal map generation method taking into account a driver's acceleration habits, comprising the following specific steps:

[0047] Step 1: Collect real-time speed through vehicle sensors With acceleration ,After the driver drives for a period of time, the driver’s acceleration and speed data set is obtained for subsequent data analysis.

[0048] Step 2: Use the multivariate kernel density estimation method to estimate the acceleration in the acceleration and velocity data set obtained in step 1 and speed The probability density of binary variables is estimated. The specific formula of binary kernel density estimation is as follows:

[0049] ;

[0050] In the formula, For at point x The kernel density estimate at n is the sample size, h is the bandwidth, K is the kernel function, is the sample point.

[0051] In the probability density of the binary variables acceleration and velocity Finally, the polygon fitting method is used to fit the driver's acceleration-speed distribution characteristic envelope into a diamond, and then the boundary of the driver's comfortable acceleration area is obtained. The boundary of the comfortable acceleration area is different for different drivers or the same driver in different driving conditions, which can characterize the driver's acceleration habits. The expression of the driver's comfort area boundary is as follows:

[0052] ;

[0053] In the formula, To stabilize the vehicle speed; Acceleration for driver comfort; f The mapping relationship between the two.

[0054] Step 3: After obtaining the boundary of the driver's comfortable acceleration zone, design the accelerator pedal opening and the vehicle's stable speed The mapping relationship between the pedal opening and the driver's comfortable acceleration is as follows:

[0055] ;

[0056] In the formula, is the accelerator pedal opening; Acceleration for driver comfort, F The mapping relationship between the two.

[0057] Step 4: The proposed pedal map considering the driver's acceleration habits has the following basic requirements:

[0058] (1) Pedal map can adapt to the driver’s acceleration habits;

[0059] (2) The pedal map can be iteratively updated in real time within a certain time window;

[0060] (3) The pedal map must meet the driver’s comfort needs;

[0061] (4) The pedal map must meet the acceleration capabilities under extreme conditions.

[0062] Therefore, the pedal map is divided into a comfortable acceleration zone and an extreme acceleration zone. The comfortable acceleration zone requires a fast acceleration response during initial acceleration, so that the driver can quickly reach the acceleration expected by the driver under re-acceleration conditions. For the extreme acceleration zone, the pedal map is required to reach the vehicle's extreme acceleration faster to meet the driver's needs under emergency conditions.

[0063] Based on the driver's comfortable acceleration area obtained in step 2, the physical meaning of the intersection of the comfortable acceleration area boundary and the horizontal axis represents the driver's speed The psychological comfort acceleration at this speed is 0, so it is taken as the psychological critical speed, that is, the driver's expected acceleration at this speed is 0, and the driver no longer expects acceleration at this speed until the limit situation is encountered. As the critical speed between the comfortable acceleration zone and the extreme acceleration zone, that is, the speed is greater than The driver no longer expects acceleration and will only accelerate under extreme conditions and without reaching the vehicle's performance limit.

[0064] Based on the mapping relationship between the accelerator pedal opening and the vehicle stable speed, the critical speed Mapped to critical pedal opening , and can also stabilize the vehicle speed within the driver's comfortable acceleration zone boundary Corresponding maximum comfortable acceleration Converted into accelerator pedal opening The corresponding comfortable acceleration.

[0065] Step 5: Based on the critical pedal opening obtained above At the same time, the vehicle's limit acceleration at a certain stable speed is obtained based on the vehicle's overall parameters, and then converted into the vehicle's limit acceleration corresponding to a certain pedal opening .

[0066] Step 6: Based on the feature points obtained in the above steps, a logarithmic function is used to generate a pedal map of the comfortable acceleration zone. The specific expression formula is as follows:

[0067] ;

[0068] In the formula, The acceleration expected by the driver; is the coefficient of the logarithmic function, which can be determined by the driver's comfortable acceleration , and accelerator pedal opening Critical pedal opening obtain; among them Critical pedal opening Accelerator pedal opening difference; C is the acceleration constant.

[0069] For the generation of pedal map in the extreme acceleration zone, considering the smooth connection of smooth curves and the need to respond quickly to acceleration, the design of the extreme acceleration pedal map is expressed by an exponential function. The specific expression is as follows:

[0070] ;

[0071] In the formula, The acceleration expected by the driver; is the coefficient of the exponential function, which can be obtained from the vehicle performance limit acceleration , and accelerator pedal opening Critical pedal opening obtain; among them is the critical pedal opening; is the accelerator pedal opening; C is the acceleration constant.

[0072] Step 7: The final pedal map can be obtained by combining the above exponential function and logarithmic function expressions. Due to the different acceleration habits of drivers, the critical speeds of the pedal map are inconsistent, and the drivers have different comfortable accelerations at the critical speeds. In addition, the driver's driving data can be updated online in real time. When the driver feels that the pedal map is too aggressive or conservative, the driver will have a smaller or larger acceleration distribution at this speed, so that the comfortable acceleration will iteratively become smaller or larger during the next window update, thereby achieving the purpose of adaptive driver in the pedal map generation process. Therefore, when the driver's acceleration habits change, this method can dynamically generate a pedal map that is synchronized with the acceleration habits.

[0073] As a preferred embodiment of the present invention, a pure electric passenger car with a motor as a power source is taken as a research object, wherein the parameters of the whole vehicle are shown in the following Table 1:

[0074] Table 1 Vehicle parameters

[0075] ;

[0076] The functional architecture used is as follows Figure 1 As shown in the figure, the pedal map generation flow chart of the adaptive driver acceleration habit is as follows Figure 2 shown.

[0077] Step 1: The vehicle speed can be collected through a magnetic speed sensor or a Hall effect sensor , and then the corresponding acceleration can be obtained by dividing the difference between the two sampling time speeds by the sampling step size , the specific expression is as follows.

[0078] ;

[0079] In the formula, For the k +1 moment speed, For the k The speed of time, For the k +1 time stamp, For the k The timestamp of the moment, For the k The acceleration of time.

[0080] The acceleration obtained from the above formula and the collected speed data can form a data set for probability distribution analysis. The kernel density estimation method and curve fitting can be used to obtain the driver's comfortable acceleration area, thereby obtaining the driver's comfortable acceleration boundary, comfortable acceleration area and critical speed, such as Figure 3 shown.

[0081] Step 2: Calculate the vehicle's driving resistance using the vehicle's frontal area and the vehicle's rolling resistance coefficient , the specific formula is as follows (this embodiment considers driving on a flat road, so the slope resistance is not considered):

[0082] ;

[0083] In the formula, G is the gross weight of the vehicle, f is the rolling resistance coefficient, is the air resistance coefficient, A is the frontal area of ​​the vehicle, To stabilize the vehicle speed.

[0084] Based on vehicle driving resistance , and then according to the external characteristic curve of the motor, the vehicle's limit acceleration can be obtained. The calculation formula of the vehicle's limit acceleration is as follows:

[0085] ;

[0086] In the formula, is the external characteristic curve of the motor at a certain speed, m is the vehicle mass, i is the main reducer speed ratio, is the driving resistance, r is the tire rolling radius, is the vehicle's limit acceleration at a certain stable speed, is the total driving force of the vehicle.

[0087] Step 3: After obtaining the maximum speed, the creeping mode speed of electric vehicles is usually controlled within a lower speed range to ensure driving comfort and safety. =5km / h. Considering the predictability of the speed by the driver, the pedal stability value and speed are linearly distributed, and the relationship between the driver's pedal opening and the stable vehicle speed can be obtained, as follows:

[0088] ;

[0089] In the formula, To stabilize the vehicle speed, is the minimum stable speed, is the maximum speed, is the accelerator pedal opening.

[0090] Step 4: Based on the driver's comfortable acceleration area and comfortable acceleration boundary, the critical speed can be obtained through the intersection of the comfortable acceleration boundary and the horizontal axis. Based on the mapping relationship between the accelerator pedal opening and the vehicle stable speed described in step 3, the critical speed Mapped to critical pedal opening and stabilize the vehicle speed within the driver's comfortable acceleration boundary Corresponding comfortable acceleration Projection is the accelerator pedal opening Corresponding comfortable acceleration , such as Figure 4 shown.

[0091] Step 5: Generate a pedal map that is adaptive to the driver's acceleration habits, obtained through steps 2, 3, and 4 respectively:

[0092] (1) Correspondence between pedal opening and stable vehicle speed ;

[0093] (2) Vehicle acceleration limit corresponding to each stable speed With coasting deceleration ;

[0094] (3) Maximum comfortable acceleration at each stable vehicle speed ;

[0095] (4) Critical speed The driver's pedal map is generated based on the

[0096] Then the pedal map is divided into a comfortable acceleration zone and a limit acceleration zone. The mapping relationship between the accelerator pedal opening and the acceleration zone is modeled respectively. For the pedal map modeling method of the comfortable acceleration zone, a logarithmic function is used for modeling. For the pedal map modeling method of the limit acceleration zone, an exponential function is used for modeling, considering the smooth connection of the smooth curve and the need to respond quickly to acceleration. The final effect is as follows Figure 5 shown.

[0097] Step 6: Based on the modeling method determined in step 5, determine the mapping relationship between the accelerator pedal opening and the acceleration, and then generate the driver's pedal map. Figure 6 and Figure 7 That is, pedal maps with different acceleration habits are generated for two drivers with different acceleration habits.

[0098] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A pedal map generation method considering the driver's acceleration habits, characterized in that: The specific steps include: Step 1: Collect real-time speed through vehicle sensors With acceleration , after the driver has driven for a period of time, the driver's acceleration and speed data set is obtained for subsequent data analysis; Step 2: Use the multivariate kernel density estimation method to estimate the acceleration in the acceleration and velocity data set obtained in step 1 and speed The probability density of binary variables is estimated, and the probability density of binary variables of acceleration and speed is obtained. Finally, the polygon fitting method is used to fit the driver's acceleration-speed distribution characteristic envelope into a rhombus, and then the boundary of the driver's comfortable acceleration area is obtained. The boundary expression of the driver's comfortable area is as follows: ； In the formula, To stabilize the vehicle speed; Acceleration for driver comfort; f is the mapping relationship between the two; Step 3: After obtaining the boundary of the driver's comfortable acceleration zone, design the accelerator pedal opening and the vehicle's stable speed The mapping relationship between the pedal opening and the driver's comfortable acceleration is as follows: ； In the formula, is the accelerator pedal opening; Acceleration for driver comfort, F is the mapping relationship between the two; Step 4: Divide the pedal map into a comfortable acceleration zone and a limit acceleration zone; based on the driver's comfortable acceleration zone obtained in step 2, calculate the speed at the intersection of the boundary of the comfortable acceleration zone and the horizontal axis. As the critical speed between the comfortable acceleration zone and the extreme acceleration zone, when the speed is greater than When the vehicle is in a state of acceleration, the driver no longer expects to accelerate and will only accelerate under extreme conditions and when the acceleration does not reach the vehicle's performance limit. Based on the mapping relationship between the accelerator pedal opening and the vehicle stable speed, the critical speed Mapped to critical pedal opening , and can also stabilize the vehicle speed within the driver's comfortable acceleration zone boundary Corresponding maximum comfortable acceleration Converted into accelerator pedal opening The corresponding comfortable acceleration; Step 5: Based on the obtained critical pedal opening At the same time, the vehicle's limit acceleration at a certain stable speed is obtained based on the vehicle's overall parameters, and then converted into the vehicle's limit acceleration corresponding to a certain pedal opening ; Step 6: Based on the feature points obtained in the above steps, a logarithmic function is used to generate a pedal map of the comfortable acceleration zone. The specific expression formula is as follows: ； In the formula, The acceleration expected by the driver; is the coefficient of the logarithmic function, which is determined by the driver's comfortable acceleration , and accelerator pedal opening Critical pedal opening obtain; among them Critical pedal opening Accelerator pedal opening difference; C is the acceleration constant; For the generation of pedal map in the extreme acceleration zone, an exponential function is used to express it. The specific expression is as follows: ； In the formula, The acceleration expected by the driver; is the coefficient of the exponential function, which is determined by the vehicle performance limit acceleration , and accelerator pedal opening Critical pedal opening obtain; among them is the critical pedal opening; is the accelerator pedal opening; C is the acceleration constant; Step 7: The final pedal map is obtained by combining the above exponential function and logarithmic function expressions. In addition, the driver's driving data can be updated online in real time. When the driver feels that the pedal map is too aggressive or conservative, the driver will have a smaller or larger acceleration distribution at this speed, so that when the next window is updated, the comfortable acceleration will iteratively become smaller or larger, thereby achieving the purpose of adaptive driver in the pedal map generation process.

2. The pedal map generation method considering the driver's acceleration habits according to claim 1, characterized in that: In step 2, the specific binary kernel density estimation method formula is as follows: ； In the formula, For at point x The kernel density estimate at n is the sample size, h is the bandwidth, K is the kernel function, is the sample point.

3. The pedal map generation method considering the driver's acceleration habits according to claim 2, characterized in that: In step 2, the vehicle driving resistance is calculated by the vehicle frontal area and the vehicle rolling resistance coefficient. , the specific formula is as follows: ； In the formula, G is the gross weight of the vehicle, f is the rolling resistance coefficient, is the air resistance coefficient, A is the frontal area of ​​the vehicle, To stabilize the vehicle speed; Based on vehicle driving resistance , and then the vehicle's limit acceleration is obtained according to the motor's external characteristic curve. The calculation formula for the vehicle's limit acceleration is as follows: ； In the formula, is the external characteristic curve of the motor at a certain speed, m is the vehicle mass, i is the main reducer speed ratio, is the driving resistance, r is the tire rolling radius, is the vehicle's limit acceleration at a certain stable speed, is the total driving force of the vehicle.

4. The pedal map generation method considering the driver's acceleration habits according to claim 3, characterized in that: In step 3, after obtaining the maximum vehicle speed, the minimum vehicle speed is taken as =5km / h; Considering the predictability of the speed by the driver, the pedal stability value and speed are linearly distributed, and the relationship between the driver's pedal opening and the stable vehicle speed can be obtained, as follows: ； In the formula, To stabilize the vehicle speed, is the minimum stable speed, is the maximum speed, is the accelerator pedal opening.

5. The pedal map generation method considering the driver's acceleration habits according to claim 1, characterized in that: In step 1, the vehicle speed is collected by a magnetoelectric vehicle speed sensor or a Hall effect sensor, and the corresponding acceleration is obtained by dividing the difference between the speeds at two sampling times by the sampling step length.

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