A variable angle transmission ratio speed rotation angle boundary division method based on driver style

Abstract

The application discloses a variable angle transmission ratio speed rotation angle boundary division method based on a driver style, which collects driver data, driver operation behavior data, vehicle data and road environment data; establishes a driver style recognition model based on the driver data, divides the drivers and outputs driver style factors; calculates speed range influence factors and steering wheel rotation angle range influence factors according to the driver operation behavior data, the road environment data, the vehicle data and the driver style factors, and corrects the basic speed range and the basic steering wheel rotation angle range; and inputs the obtained personalized speed range and personalized steering wheel rotation angle range as the boundary of a variable angle transmission ratio surface design, so that the preset variable angle transmission ratio surface is adjusted personally. The application can adapt the variable angle transmission ratio design boundary to the driver operation habit and the road environment difference, and improve the personalization degree and the steering matching property of the steer-by-wire system.

Description

Technical Field

[0001] This invention relates to the field of vehicle steer-by-wire systems and variable angle transmission ratio design technology, and in particular to a method for dividing the speed-angle boundary of variable angle transmission ratio based on driver style. Background Technology

[0002] The steer-by-wire system eliminates the mechanical connection between the steering wheel and the steering actuator, and can flexibly set the correspondence between the steering wheel angle and the steering wheel angle through control algorithms. Compared with the traditional mechanical steering system, the steer-by-wire system can adjust the angle transmission ratio according to vehicle speed, steering wheel angle, vehicle status, and driver characteristics, thus balancing low-speed steering agility and high-speed driving stability.

[0003] In variable angle transmission ratio design, it is usually necessary to first divide the speed range into low-speed segment, low-speed to medium-speed transition segment, medium-speed segment, medium-speed to high-speed transition segment, and high-speed segment, and then construct the variable angle transmission ratio surface based on the target steering response characteristics of each speed segment. At the same time, the steering wheel angle range will also affect the expansion range of the variable angle transmission ratio surface in the steering angle dimension and the response characteristics in the central area.

[0004] Existing variable angle transmission ratio design methods often employ fixed speed segment boundaries and fixed steering wheel angle boundaries, which typically fail to reflect the differences in driving habits among drivers. For example, cautious drivers usually prefer the vehicle to enter the more stable medium-to-high speed steering response range earlier; aggressive drivers may be more accepting of a wider low-to-medium speed response range and a larger steering input range; and average drivers fall somewhere in between. If a uniform boundary is still used for variable angle transmission ratio design, it is easy to cause a mismatch between the variable angle transmission ratio surface and the driver's style, affecting the personalization and handling compatibility of the steer-by-wire system.

[0005] Therefore, it is necessary to propose a method that can personalize the speed segment boundaries and steering wheel angle boundaries by combining driver style, driver operation behavior, vehicle status and road environment, so that the variable angle transmission ratio surface design boundary can better adapt to the different operating habits of different drivers and the differences in road environment. Summary of the Invention

[0006] The purpose of this invention is to provide a method for delineating the speed-angle boundary of a variable-angle transmission ratio based on driver style. This method collects driver data, driver operation behavior data, vehicle data, and road environment data; performs synchronization, filtering, and outlier removal on the collected data; and applies range limitations to the data. Based on the driver data, a driver style recognition model is established to identify drivers as cautious, moderate, or aggressive, and a driver style factor is output. Based on the driver operation behavior data, road environment data, vehicle data, and driver style factor, an environmental influence factor and a driver speed influence factor are calculated, and then a speed range influence factor is calculated. The speed range influence factor is then used to... The degree range influence factor is used to correct the basic speed range to obtain a personalized speed range. Based on driver operation behavior data and vehicle data, the maximum absolute value influence factor of steering wheel angle and the steering wheel angle velocity influence factor are calculated, and then the steering wheel angle range influence factor is calculated. The basic steering wheel angle range is corrected using the steering wheel angle range influence factor to obtain a personalized steering wheel angle range. The personalized speed range and personalized steering wheel angle range are used as boundary inputs for the variable angle transmission ratio surface design, so that the preset variable angle transmission ratio surface is adjusted according to the personalized speed range and personalized steering wheel angle range to obtain a personalized variable angle transmission ratio surface.

[0007] This invention is implemented as follows: a method for dividing the speed angle boundary of a variable angle transmission ratio based on driver style, comprising the following steps:

[0008] S1: Collect driver data, driver operation behavior data, vehicle data and road environment data, perform synchronization, filtering and outlier removal on the collected data, and perform range restriction processing on the data;

[0009] The range limitation process is implemented using a limiting function, which is:

[0010]

[0011] in, For the amplitude limiting function, As the independent variable, This is the lower limit of the amplitude limiting function. This is the upper limit of the amplitude limiting function;

[0012] S2: Based on the driver data, identify the driver style using the established driver style recognition model, and output a driver style factor according to the driver style. ;

[0013] S3: Based on driver behavior data, road environment data, vehicle data, and driver style factors. Calculate environmental impact factors Driver speed influence factor Then, the speed range influence factor is calculated, and the basic speed range is corrected using the speed range influence factor to obtain the personalized speed range.

[0014] S4: Calculate the influencing factor of the maximum absolute value of steering wheel angle based on driver operation behavior data and vehicle data. Factors affecting steering wheel angular velocity Then, the steering wheel angle range influence factor is calculated, and the basic steering wheel angle range is corrected using the steering wheel angle range influence factor to obtain the personalized steering wheel angle range.

[0015] S5: Use the personalized speed range and personalized steering wheel angle range as the boundary input for the variable angle transmission ratio surface design, so that the preset variable angle transmission ratio surface is adjusted according to the personalized speed range and personalized steering wheel angle range to obtain the personalized variable angle transmission ratio surface.

[0016] The personalized speed range is obtained by introducing a speed range influence factor on top of the basic speed range;

[0017] The basic speed range is as follows:

[0018] Low speed range: Low-speed to medium-speed transition section: ;Medium speed section: Medium-speed to high-speed transition section: High-speed section: ;

[0019] in, The longitudinal speed of the vehicle. This is the lower boundary of the low-speed segment. This is the upper boundary of the low-speed segment. This is the lower boundary of the medium-speed range. This is the upper boundary of the medium-speed range. This is the lower boundary of the high-speed section. This is the upper boundary of the high-speed section. Select according to specific needs;

[0020] The personalized speed range is as follows:

[0021] Low speed range: Low-speed to medium-speed transition section: ;Medium speed section: Medium-speed to high-speed transition section: High-speed section: ;

[0022] in: , , , , ,

[0023] in, For the personalized low-speed segment lower boundary, For the personalized low-speed segment upper boundary, For the personalized mid-speed range lower boundary, For the personalized mid-speed range upper boundary, For the lower boundary of the personalized high-speed section, For the personalized upper boundary of the high-speed section, The influencing factor for the lower boundary velocity range at low speeds. The influencing factor for the upper boundary speed range of low speed. The influencing factor for the lower boundary velocity range of medium speed. The influencing factor for the upper boundary speed range of medium speed. The influencing factor for the lower boundary speed range at high speed. The influence factor for the upper boundary speed range of high-speed;

[0024] Calculated , Afterwards, if ,but ;like ,but ;

[0025] in, This is the adjustment coefficient for the medium speed range. ; This is the high-speed range adjustment coefficient. ; , Select according to the actual situation;

[0026] Through the above boundary overlap correction, the personalized speed range must be satisfied. This ensures that the division order of low-speed segment, low-speed to medium-speed transition segment, medium-speed segment, medium-speed to high-speed transition segment, and high-speed segment does not overlap;

[0027] The specific calculation formula for the speed range influence factor is as follows:

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034] in, This is the lower limit of the speed influence factor. This represents the upper limit of the speed influence factor. As an environmental impact factor, As a factor affecting driver speed, Weights are assigned to the low-speed lower boundary environment. The weighting of driver speed at the lower boundary of low speed is determined. Weights are assigned to the low-speed upper boundary environment. The weighting of driver speed influence at the low-speed upper boundary. As the weight for the impact of the lower boundary environment at medium speed, The weighting of driver speed at the lower boundary of the medium speed range. Assign weights to the environmental impact of the upper boundary of the medium-speed range. The weighting of driver speed influence at the upper boundary of the medium speed range. The environmental impact weight at the lower boundary of the high-speed section. The weighting of driver speed at the lower boundary of the high-speed section. Assigning environmental impact weights to the upper boundary of the high-speed section. The weighting of driver speed at the upper boundary of the high-speed section. Select according to specific needs, and , , , , , , .

[0035] The personalized steering wheel angle range is obtained by introducing a steering wheel angle range influence factor based on the basic steering wheel angle range setting;

[0036] The specific range of the basic steering wheel angle is as follows:

[0037]

[0038] in, For steering wheel angle, The lower boundary of the steering wheel angle. The upper boundary of the steering wheel angle; , The value can be modified according to specific needs;

[0039] The specific range of the personalized steering wheel angle is as follows:

[0040]

[0041] in: ;

[0042] in, To personalize the lower boundary of the steering wheel angle, To personalize the upper boundary of the steering wheel angle, This is the lower boundary influence factor of the steering wheel angle range. This is the influence factor for the upper boundary of the steering wheel angle range;

[0043] The specific calculation formula for the steering wheel angle range influencing factor is as follows:

[0044]

[0045]

[0046] in, This represents the lower limit of the influencing factor on the steering wheel angle range. This represents the upper limit of the influencing factor on the steering wheel angle range. The factor influencing the maximum absolute value of the steering wheel angle. The influencing factor of steering wheel angular velocity. The lower limit of the range is affected by the maximum absolute value of the steering wheel angle. The lower limit of the range is determined by the influence of steering wheel angular velocity on the weight. The maximum absolute value of the steering wheel angle affects the weighting of the upper limit of the range. The upper limit of the range is affected by the steering wheel angular velocity. Select according to specific needs, and , , , , .

[0047] The driver style recognition model is constructed using a semi-supervised support vector machine algorithm, which can classify drivers into cautious, average, and aggressive types.

[0048] The driver style factor When the driver is identified as cautious When the driver is identified as a general type When the driver is identified as aggressive ;

[0049] The environmental impact factors The calculation formula is as follows:

[0050]

[0051] in, As an environmental impact factor, The road surface adhesion coefficient, , Traffic density, This refers to the road surface adhesion coefficient and reinforcement coefficient. , This is the traffic density attenuation coefficient. , This is the traffic flow density half-saturation adjustment coefficient. , This is the traffic density index coefficient. ;

[0052] Traffic density This refers to the number of vehicles per unit road length, expressed in vehicles / km.

[0053] The driver speed influence factor The calculation formula is as follows:

[0054]

[0055] in, As a factor affecting driver speed, For drivers to identify highway boundaries, Identify the low-speed dividing line for drivers. , For driver style factors, The high-speed boundary line affects the weighting. The low-speed dividing line affects the weight. The driver style influences the weighting. , This is the normalization coefficient for the deviation of the high-speed boundary line. , This is the normalization coefficient for the low-speed boundary deviation. ;

[0056] The driver identified the highway dividing line This refers to the speed boundary value, expressed in km / h, that a driver subjectively considers when transitioning from a medium-speed to a high-speed driving state, based on their driving experience, vehicle handling feel, and road traffic conditions. At that time, the driver believes the vehicle has not yet entered a high-speed driving state; when the vehicle's speed is greater than or equal to... At that time, the driver believed that the vehicle was gradually moving from a medium speed to a high speed.

[0057] The driver identified the low-speed dividing line. This refers to the speed boundary value, expressed in km / h, that a driver subjectively considers when transitioning from a low-speed to a medium-speed driving state, based on their driving experience, vehicle handling feel, and road traffic conditions. When the vehicle speed is less than or equal to... At that time, the driver believes the vehicle is traveling at a low speed; when the vehicle's speed exceeds a certain threshold... At that time, the driver believed that the vehicle was gradually moving from a low speed to a medium speed.

[0058] The influencing factor of the maximum absolute value of the steering wheel angle The calculation formula is as follows:

[0059]

[0060] in, For driver comfort steering angle threshold, The driver's habitual maximum steering input angle, The upper boundary of the steering wheel angle. The maximum absolute value of the steering wheel angle. The average absolute value of the steering wheel angle. The steering input percentage is the baseline value. The average duration of the driver's steering action. This serves as a baseline value for the duration of the steering maneuver. , The weighting of the comfort steering angle threshold is determined by the following factors. The weighting is determined by the influence of the habitual maximum steering input angle. The actual maximum steering input angle influences the weight. The weighting is determined by the proportion of input usage used in the shift. The duration of the steering action affects the weighting. , Normalized scale for comfort steering angle deviation , The normalized scale is the habitual maximum steering input angle deviation. , The normalized scale is the actual maximum steering input angle deviation. , As a normalized scale for the deviation of the steering input ratio, , The normalized scale for the deviation in steering action duration. , For a very small correction amount, ;

[0061] The driver's habitual maximum steering input angle This is the statistical maximum value of the absolute value of the steering wheel angle in the driver's historical driving data, used to characterize the maximum steering wheel angle input amplitude that the driver is accustomed to using during normal driving.

[0062] The driver comfort steering angle threshold The easy steering angle value is the driver's subjective perception of the upper limit of the steering wheel angle that the driver can accept without significantly increasing the handling burden. It can be obtained through driver subjective evaluation, driving simulator calibration test and historical steering data statistics.

[0063] The average duration of the driver's steering action The average duration of a driver’s continuous steering input habit is the time from the start of a valid steering action to the end of that steering action in a historical driving test. It is used to characterize the driver’s continuous steering input habit and is measured in seconds.

[0064] The steering wheel angular velocity influencing factor The calculation formula is as follows:

[0065]

[0066] in, For driver comfort steering angular velocity threshold, The driver's habitual maximum steering angular velocity, The upper boundary of the basic steering wheel angular velocity. This is the actual maximum steering wheel angular velocity. This represents the actual average steering wheel angular velocity. The root mean square of the acceleration due to the steering wheel angle is... Use the percentage reference value for steering angular velocity. , As a benchmark value for the degree of abrupt change in direction, , The weighting of the comfort steering angular velocity threshold influences the following: The weighting is determined by the influence of the habitual maximum steering angular velocity. The actual maximum steering angular velocity influences the weight. The weighting of the percentage of steering angular velocity used affects the overall weighting. To suppress the degree of shift mutation, , To normalize the deviation of steering angle rate for comfort, , The normalized scale for the habitual maximum steering angular velocity deviation is... , The normalized scale for the actual maximum steering angular velocity deviation. , The percentage deviation normalization scale is used for the steering angular velocity. , As a normalized scale for the degree of deviation of the shift, ;

[0067] The driver's habitual maximum steering angular velocity This represents the maximum absolute value of the steering wheel angular velocity in the driver's historical driving data, used to characterize the driver's habitual steering operation speed.

[0068] This invention has the following beneficial effects: It can modify the speed segment boundaries according to the driver's style, making the low-speed, medium-speed, high-speed and their transition ranges more in line with the speed perception and driving habits of different drivers; It can modify the steering wheel angle boundary according to the driver's steering input amplitude and steering angular velocity characteristics, making the variable angle transmission ratio surface more in line with the driver's operating habits in the angular dimension; It incorporates road environment, driver style and vehicle status into the boundary division process, improving the personalization and handling matching of the steer-by-wire variable angle transmission ratio design. Attached Figure Description

[0069] Figure 1 This is a schematic diagram of the overall process of the method of the present invention;

[0070] Figure 2 A diagram showing the change in angular transmission ratio with vehicle speed when the steering wheel angle is 0°.

[0071] Figure 3 This is a schematic diagram comparing the preset variable angle transmission ratio surface and the customized variable angle transmission ratio surface. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of this invention clearer, the following is combined with... Figure 1 , Figure 2 and Figure 3 The present invention will be described in more detail below. It is understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention. Where there is no conflict, the embodiments and technical features of the present invention can be combined with each other.

[0073] like Figure 1As shown, this invention collects driver data, driver operation behavior data, vehicle data, and road environment data. The data undergoes synchronization, filtering, and outlier removal processing, and range limitation processing is applied. A driver style recognition model is established based on the driver data, identifying drivers as cautious, moderate, or aggressive, and outputting driver style factors. Based on driver operation behavior data, road environment data, vehicle data, and driver style factors, environmental influence factors and driver speed influence factors are calculated, followed by a speed range influence factor. The base speed range is then corrected using these speed range influence factors to obtain a personalized speed range. Based on driver operation behavior data and vehicle data, the maximum absolute value influence factor of the steering wheel angle and the steering wheel angle velocity influence factor are calculated, followed by a steering wheel angle range influence factor. The base steering wheel angle range is then corrected using these steering wheel angle range influence factors to obtain a personalized steering wheel angle range. These personalized speed ranges and personalized steering wheel angle ranges are used as boundary inputs for the design of a variable angle transmission ratio surface. The preset variable angle transmission ratio surface is adjusted according to these personalized speed ranges and personalized steering wheel angle ranges to obtain a personalized variable angle transmission ratio surface.

[0074] S1: Collect driver data, driver operation behavior data, vehicle data and road environment data, perform synchronization, filtering and outlier removal on the collected data, and perform range restriction processing on the data;

[0075] The range limitation process is implemented using a limiting function, which is:

[0076]

[0077] in, For the amplitude limiting function, As the independent variable, This is the lower limit of the amplitude limiting function. This is the upper limit of the amplitude limiting function;

[0078] S2: Based on the driver data, identify the driver style using the established driver style recognition model, and output a driver style factor according to the driver style. ;

[0079] The driver style recognition model is constructed using a semi-supervised support vector machine algorithm, which can classify drivers into cautious, average, and aggressive types.

[0080] The driver style factor When the driver is identified as cautious When the driver is identified as a general type When the driver is identified as aggressive ;

[0081] S3: Based on driver behavior data, road environment data, vehicle data, and driver style factors. Calculate environmental impact factors Driver speed influence factor Then, the speed range influence factor is calculated, and the basic speed range is corrected using the speed range influence factor to obtain the personalized speed range.

[0082] The personalized speed range is obtained by introducing a speed range influence factor on top of the basic speed range;

[0083] The basic speed range is as follows:

[0084] Low speed range: Low-speed to medium-speed transition section: ;Medium speed section: Medium-speed to high-speed transition section: High-speed section: ;

[0085] in, The longitudinal speed of the vehicle, expressed in km / h. This is the lower boundary of the low-speed segment. This is the upper boundary of the low-speed segment. This is the lower boundary of the medium-speed range. This is the upper boundary of the medium-speed range. This is the lower boundary of the high-speed section. This is the upper boundary of the high-speed section. Select according to specific needs;

[0086] The personalized speed range is as follows:

[0087] Low speed range: Low-speed to medium-speed transition section: ;Medium speed section: Medium-speed to high-speed transition section: High-speed section: ;

[0088] in: , , , , ,

[0089] in, For the personalized low-speed segment lower boundary, For the personalized low-speed segment upper boundary, For the personalized mid-speed range lower boundary, For the personalized mid-speed range upper boundary, For the lower boundary of the personalized high-speed section, For the personalized upper boundary of the high-speed section, The influencing factor for the lower boundary velocity range at low speeds. The influencing factor for the upper boundary speed range of low speed. The influencing factor for the lower boundary velocity range of medium speed. The influencing factor for the upper boundary speed range of medium speed. The influencing factor for the lower boundary speed range at high speed. The influence factor for the upper boundary speed range of high-speed;

[0090] Calculated , Afterwards, if ,but ;like ,but ;

[0091] in, This is the adjustment coefficient for the medium speed range. ; This is the high-speed range adjustment coefficient. ; , Select according to the actual situation;

[0092] Through the above boundary overlap correction, the personalized speed range must be satisfied. This ensures that the division order of low-speed segment, low-speed to medium-speed transition segment, medium-speed segment, medium-speed to high-speed transition segment, and high-speed segment does not overlap;

[0093] The specific calculation formula for the speed range influence factor is as follows:

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100] in, This is the lower limit of the speed influence factor. This represents the upper limit of the speed influence factor. As an environmental impact factor, As a factor affecting driver speed, Weights are assigned to the low-speed lower boundary environment. The weighting of driver speed at the lower boundary of low speed is determined. Weights are assigned to the low-speed upper boundary environment. The weighting of driver speed influence at the low-speed upper boundary. As the weight for the impact of the lower boundary environment at medium speed, The weighting of driver speed at the lower boundary of the medium speed range. Assign weights to the environmental impact of the upper boundary of the medium-speed range. The weighting of driver speed influence at the upper boundary of the medium speed range. The environmental impact weight at the lower boundary of the high-speed section. The weighting of driver speed at the lower boundary of the high-speed section. Assigning environmental impact weights to the upper boundary of the high-speed section. The weighting of driver speed at the upper boundary of the high-speed section. Select according to specific needs, and , , , , , , .

[0101] The environmental impact factors The calculation formula is as follows:

[0102]

[0103] in, As an environmental impact factor, The road surface adhesion coefficient, , Traffic density, This refers to the road surface adhesion coefficient and reinforcement coefficient. , This is the traffic density attenuation coefficient. , This is the traffic flow density half-saturation adjustment coefficient. , This is the traffic density index coefficient. ;

[0104] Traffic density This refers to the number of vehicles per unit road length, expressed in vehicles / km.

[0105] The driver speed influence factor The calculation formula is as follows:

[0106]

[0107] in, As a factor affecting driver speed, For drivers to identify highway boundaries, Identify the low-speed dividing line for drivers. , For driver style factors, The high-speed boundary line affects the weighting. The low-speed dividing line affects the weight. The driver style influences the weighting. , This is the normalization coefficient for the deviation of the high-speed boundary line. , This is the normalization coefficient for the low-speed boundary deviation. ;

[0108] The driver identified the highway dividing line This refers to the speed boundary value, expressed in km / h, that a driver subjectively considers when transitioning from a medium-speed to a high-speed driving state, based on their driving experience, vehicle handling feel, and road traffic conditions. At that time, the driver believes the vehicle has not yet entered a high-speed driving state; when the vehicle's speed is greater than or equal to... At that time, the driver believed that the vehicle was gradually moving from a medium speed to a high speed.

[0109] The driver identified the low-speed dividing line. This refers to the speed boundary value, expressed in km / h, that a driver subjectively considers when transitioning from a low-speed to a medium-speed driving state, based on their driving experience, vehicle handling feel, and road traffic conditions. When the vehicle speed is less than or equal to... At that time, the driver believes the vehicle is traveling at a low speed; when the vehicle's speed exceeds a certain threshold... At that time, the driver believed that the vehicle was gradually moving from a low speed to a medium speed.

[0110] S4: Calculate the influencing factor of the maximum absolute value of steering wheel angle based on driver operation behavior data and vehicle data. Factors affecting steering wheel angular velocity Then, the steering wheel angle range influence factor is calculated, and the basic steering wheel angle range is corrected using the steering wheel angle range influence factor to obtain the personalized steering wheel angle range.

[0111] The personalized steering wheel angle range is obtained by introducing a steering wheel angle range influence factor based on the basic steering wheel angle range setting;

[0112] The specific range of the basic steering wheel angle is as follows:

[0113]

[0114] in, For steering wheel angle, The lower boundary of the steering wheel angle. The upper boundary of the steering wheel angle; , The value can be modified according to specific needs;

[0115] The specific range of the personalized steering wheel angle is as follows:

[0116]

[0117] in: ;

[0118] in, To personalize the lower boundary of the steering wheel angle, To personalize the upper boundary of the steering wheel angle, This is the lower boundary influence factor of the steering wheel angle range. This is the influence factor for the upper boundary of the steering wheel angle range;

[0119] The specific calculation formula for the steering wheel angle range influencing factor is as follows:

[0120]

[0121]

[0122] in, This represents the lower limit of the influencing factor on the steering wheel angle range. This represents the upper limit of the influencing factor on the steering wheel angle range. The factor influencing the maximum absolute value of the steering wheel angle. The influencing factor of steering wheel angular velocity. The lower limit of the range is affected by the maximum absolute value of the steering wheel angle. The lower limit of the range is determined by the influence of steering wheel angular velocity on the weight. The maximum absolute value of the steering wheel angle affects the weighting of the upper limit of the range. The upper limit of the range is affected by the steering wheel angular velocity. Select according to specific needs, and , , , , .

[0123] The influencing factor of the maximum absolute value of the steering wheel angle The calculation formula is as follows:

[0124]

[0125] in, For driver comfort steering angle threshold, The driver's habitual maximum steering input angle, The upper boundary of the steering wheel angle. The maximum absolute value of the steering wheel angle. The average absolute value of the steering wheel angle. The steering input percentage is the baseline value. The average duration of the driver's steering action. This serves as a baseline value for the duration of the steering maneuver. , The weighting of the comfort steering angle threshold is determined by the following factors. The weighting is determined by the influence of the habitual maximum steering input angle. The actual maximum steering input angle influences the weight. The weighting is determined by the proportion of input usage used in the shift. The duration of the steering action affects the weighting. , Normalized scale for comfort steering angle deviation , The normalized scale is the habitual maximum steering input angle deviation. , The normalized scale is the actual maximum steering input angle deviation. , As a normalized scale for the deviation of the steering input ratio, , The normalized scale for the deviation in steering action duration. , For a very small correction amount, ;

[0126] The driver's habitual maximum steering input angle This is the statistical maximum value of the absolute value of the steering wheel angle in the driver's historical driving data, used to characterize the maximum steering wheel angle input amplitude that the driver is accustomed to using during normal driving.

[0127] The driver comfort steering angle threshold The easy steering angle value is the driver's subjective perception of the upper limit of the steering wheel angle that the driver can accept without significantly increasing the handling burden. It can be obtained through driver subjective evaluation, driving simulator calibration test and historical steering data statistics.

[0128] The average duration of the driver's steering action The average duration of a driver’s continuous steering input habit is the time from the start of a valid steering action to the end of that steering action in a historical driving test. It is used to characterize the driver’s continuous steering input habit and is measured in seconds.

[0129] The steering wheel angular velocity influencing factor The calculation formula is as follows:

[0130]

[0131] in, For driver comfort steering angular velocity threshold, The driver's habitual maximum steering angular velocity, The upper boundary of the basic steering wheel angular velocity. This is the actual maximum steering wheel angular velocity. This represents the actual average steering wheel angular velocity. The root mean square of the acceleration due to the steering wheel angle is... Use the percentage reference value for steering angular velocity. , As a benchmark value for the degree of abrupt change in direction, , The weighting of the comfort steering angular velocity threshold influences the following: The weighting is determined by the influence of the habitual maximum steering angular velocity. The actual maximum steering angular velocity influences the weight. The weighting of the percentage of steering angular velocity used affects the overall weighting. To suppress the degree of shift mutation, , To normalize the deviation of steering angle rate for comfort, , The normalized scale for the habitual maximum steering angular velocity deviation is... , The normalized scale for the actual maximum steering angular velocity deviation. , The percentage deviation normalization scale is used for the steering angular velocity. , As a normalized scale for the degree of deviation of the shift, ;

[0132] The driver's habitual maximum steering angular velocity This represents the maximum absolute value of the steering wheel angular velocity in the driver's historical driving data, used to characterize the driver's habitual steering operation speed.

[0133] S5: Use the personalized speed range and personalized steering wheel angle range as the boundary input for the variable angle transmission ratio surface design, so that the preset variable angle transmission ratio surface is adjusted according to the personalized speed range and personalized steering wheel angle range to obtain the personalized variable angle transmission ratio surface.

[0134] In this embodiment of the invention, the preset variable angle transmission ratio surface designs the variable angle transmission ratio of the steer-by-wire system under different speed segments based on the method of constant yaw rate gain. Combined with a two-degree-of-freedom vehicle dynamics model, the following formula for calculating the steering variable angle transmission ratio based on constant yaw rate gain can be obtained:

[0135]

[0136]

[0137]

[0138] in, The longitudinal speed of the vehicle, in m / s. This refers to the variable angle transmission ratio of the vehicle. This represents the yaw rate gain of the vehicle as the front wheel steering angle changes. This represents the yaw rate gain of the vehicle as the steering wheel angle changes. The longitudinal speed of the vehicle, expressed in m / s. For vehicle stability factors, the unit is , For the equivalent lateral stiffness of the front wheel, For the equivalent lateral stiffness of the rear wheel, This is the distance from the front axle to the center of mass. This is the distance between the rear axle and the center of mass. For the quality of the car.

[0139] The speed segmentation design method is adopted, and the basic speed range and basic steering wheel angle range are divided to correspond to the low-speed segment variable angle transmission ratio. Variable angle transmission ratio in the low-speed to medium-speed transition section Medium-speed range variable angle transmission ratio Variable transmission ratio in the transition section from medium speed to high speed High-speed variable angle transmission ratio .

[0140] The low-speed variable angle transmission ratio The formula is as follows:

[0141]

[0142]

[0143]

[0144]

[0145] In the formula, This represents the maximum absolute value of the vehicle's steering wheel angle travel. This represents the maximum absolute value of the vehicle's front wheel steering angle. This represents the lower boundary value of the variable angle transmission ratio in the low-speed range. This represents the upper boundary value of the variable angle transmission ratio in the low-speed range. This represents the yaw rate gain value at the upper boundary of the low-speed range. This refers to the steepness coefficient in the low-speed range; The minimum gear ratio interval can be set independently according to specific requirements. .

[0146] The low-speed to medium-speed transition section variable angle transmission ratio The formula is as follows:

[0147]

[0148]

[0149]

[0150] In the formula, This represents the lower boundary value of the variable angle transmission ratio during the low-speed to medium-speed transition section. This represents the upper boundary value of the variable angle transmission ratio during the low-speed to medium-speed transition section. This is the upper boundary of the low-speed segment. This is the lower boundary of the medium-speed range. This is the steepness coefficient for the transition from low speed to medium speed.

[0151] The mid-speed range variable angle transmission ratio The formula is as follows:

[0152]

[0153]

[0154]

[0155] In the formula, This represents the lower boundary value of the variable angle transmission ratio in the medium speed range. This represents the upper boundary value of the variable angle transmission ratio in the medium-speed range. This represents the yaw rate gain value at the lower boundary of the mid-speed range. This represents the yaw rate gain value at the upper boundary of the mid-speed range. This is the steepness coefficient for the medium-speed range.

[0156] The variable angle transmission ratio in the medium-speed to high-speed transition section The formula is as follows:

[0157]

[0158]

[0159]

[0160] In the formula, This represents the lower boundary of the variable angle transmission ratio in the transition section from medium speed to high speed. This represents the upper boundary of the variable angle transmission ratio in the transition section from medium speed to high speed. This is the upper boundary of the medium-speed range. This is the lower boundary of the high-speed section. This is the steepness coefficient for the transition from medium speed to high speed.

[0161] The high-speed section variable angle transmission ratio The formula is as follows:

[0162]

[0163]

[0164]

[0165] In the formula, This represents the lower boundary of the variable angle transmission ratio in the high-speed section. This represents the upper boundary of the variable angle transmission ratio in the high-speed section. This represents the yaw rate gain value at the lower boundary of the high-speed section. This represents the yaw rate gain value at the upper boundary of the high-speed section. This represents the steepness coefficient of the high-speed section.

[0166] By replacing the basic speed segment boundary in the preset variable angle transmission ratio surface with the personalized speed range boundary, and by replacing the basic steering wheel angle range with the personalized steering wheel angle range, a personalized variable angle transmission ratio surface can be obtained.

[0167] like Figure 2 As shown, when the steering wheel angle is set to 0°, a comparison curve of the preset variable angle transmission ratio and the personalized variable angle transmission ratio as a function of vehicle speed can be obtained. Because the personalized speed range changes the boundary positions of the low-speed, medium-speed, high-speed, and transition segments, the personalized variable angle transmission ratio curve is smoothly offset in the speed dimension relative to the preset variable angle transmission ratio curve.

[0168] like Figure 3 As shown, after using the personalized speed range and personalized steering wheel angle range as boundary inputs, the preset variable angle transmission ratio surface is adjusted according to the personalized speed range and personalized steering wheel angle range to obtain the personalized variable angle transmission ratio surface. This surface has the same overall trend of change as the preset variable angle transmission ratio surface, but there are differences in the speed segment position, transition area width, and steering wheel angle range, thus reflecting the personalized influence of driver style on the boundary of the variable angle transmission ratio surface.

[0169] In this embodiment of the invention, the basic speed range is set to 0 km / h, 20 km / h, 35 km / h, 70 km / h, 90 km / h, and 120 km / h, and the basic steering wheel angle range is set to [-180°, 180°]. For aggressive drivers, if they perceive the low-speed and high-speed dividing lines to be relatively high and the road conditions to be good, the personalized speed range can be shifted towards higher speeds relative to the basic speed range; for cautious drivers, if they perceive the speed dividing lines to be low and the road conditions to be more complex, the personalized speed range can be shifted towards lower speeds relative to the basic speed range.

[0170] This invention constructs a complete process through the above steps, consisting of driver style recognition, speed range influence factor calculation, steering wheel angle range influence factor calculation, basic boundary personalization correction, and personalized variable angle transmission ratio surface generation. Specifically, the driver style factor characterizes the style differences between cautious, average, and aggressive drivers; the environmental influence factor and driver speed influence factor are used to calculate the speed range influence factor, thereby adjusting the basic speed range; the steering wheel angle absolute value maximum influence factor and steering wheel angle velocity influence factor are used to calculate the steering wheel angle range influence factor, thereby adjusting the basic steering wheel angle range. This yields personalized speed range and personalized steering wheel angle range, which are then used as boundary inputs for the variable angle transmission ratio surface design. This allows the preset variable angle transmission ratio surface to be personalized according to differences in driver style, driver operating habits, and road environment, improving the adaptability and handling matching of the variable angle transmission ratio design in the steer-by-wire system.

Claims

1. A method for dividing the speed-angle boundary of a variable-angle transmission ratio based on driver style, characterized in that, Includes the following steps: S1: Collect driver data, driver operation behavior data, vehicle data and road environment data, perform synchronization, filtering and outlier removal on the collected data, and perform range restriction processing on the data; The range limitation process is implemented using a limiting function, which is: in, For the amplitude limiting function, As the independent variable, This is the lower limit of the amplitude limiting function. This is the upper limit of the amplitude limiting function; S2: Based on the driver data, identify the driver style using the established driver style recognition model, and output a driver style factor according to the driver style. ; S3: Based on driver behavior data, road environment data, vehicle data, and driver style factors. Calculate environmental impact factors Driver speed influence factor Then, the speed range influence factor is calculated, and the basic speed range is corrected using the speed range influence factor to obtain the personalized speed range. S4: Calculate the influencing factor of the maximum absolute value of steering wheel angle based on driver operation behavior data and vehicle data. Factors affecting steering wheel angular velocity Then, the steering wheel angle range influence factor is calculated, and the basic steering wheel angle range is corrected using the steering wheel angle range influence factor to obtain the personalized steering wheel angle range. S5: Use the personalized speed range and personalized steering wheel angle range as the boundary input for the variable angle transmission ratio surface design, so that the preset variable angle transmission ratio surface is adjusted according to the personalized speed range and personalized steering wheel angle range to obtain the personalized variable angle transmission ratio surface.

2. The method for dividing the variable angle transmission ratio speed angle boundary based on driver style according to claim 1, characterized in that, The personalized speed range is obtained by introducing a speed range influence factor on top of the basic speed range; The basic speed range is as follows: Low speed range: Low-speed to medium-speed transition section: ;Medium speed section: Medium-speed to high-speed transition section: High-speed section: ; in, The longitudinal speed of the vehicle. This is the lower boundary of the low-speed segment. This is the upper boundary of the low-speed segment. This is the lower boundary of the medium-speed range. This is the upper boundary of the medium-speed range. This is the lower boundary of the high-speed section. This is the upper boundary of the high-speed section. Select according to specific needs; The personalized speed range is as follows: Low speed range: Low-speed to medium-speed transition section: ;Medium speed section: Medium-speed to high-speed transition section: High-speed section: ; in: , , , , , in, For the personalized low-speed segment lower boundary, For the personalized low-speed segment upper boundary, For the lower boundary of the personalized mid-speed range, For the personalized mid-speed range upper boundary, For the lower boundary of the personalized high-speed section, For the personalized high-speed section upper boundary, The influencing factor for the lower boundary velocity range at low speeds. The influencing factor for the upper boundary speed range of low speed. The influencing factor for the lower boundary velocity range of medium speed. The influencing factor for the upper boundary speed range of medium speed. The influencing factor for the lower boundary speed range at high speed. The influence factor for the upper boundary speed range of high-speed; Calculated , Afterwards, if ,but ;like ,but ; in, This is the adjustment coefficient for the medium speed range. ; This is the high-speed range adjustment coefficient. ; , Select according to the actual situation; Through the above boundary overlap correction, the personalized speed range must be satisfied. This ensures that the division order of low-speed segment, low-speed to medium-speed transition segment, medium-speed segment, medium-speed to high-speed transition segment, and high-speed segment does not overlap; The specific calculation formula for the speed range influence factor is as follows: in, This is the lower limit of the speed influence factor. This represents the upper limit of the speed influence factor. As an environmental impact factor, As a factor affecting driver speed, Weights are assigned to the low-speed lower boundary environment. The weighting of driver speed at the lower boundary of low speed is determined. Weights are assigned to the low-speed upper boundary environment. The weighting of driver speed influence at the low-speed upper boundary. As the weight for the impact of the lower boundary environment at medium speed, The weighting of driver speed at the lower boundary of the medium speed range. Assign weights to the environmental impact of the upper boundary of the medium-speed range. The weighting of driver speed influence at the upper boundary of the medium speed range. The environmental impact weight at the lower boundary of the high-speed section. The weighting of driver speed at the lower boundary of the high-speed section. Assigning environmental impact weights to the upper boundary of the high-speed section. The weighting of driver speed at the upper boundary of the high-speed section. Select according to specific needs, and , , , , , , .

3. The method for dividing the variable angle transmission ratio speed angle boundary based on driver style according to claim 1, characterized in that, The personalized steering wheel angle range is obtained by introducing a steering wheel angle range influence factor based on the basic steering wheel angle range setting; The specific range of the basic steering wheel angle is as follows: in, For steering wheel angle, The lower boundary of the steering wheel angle. The upper boundary of the steering wheel angle; , The value can be modified according to specific needs; The specific range of the personalized steering wheel angle is as follows: in: ; in, To personalize the lower boundary of the steering wheel angle, To personalize the upper boundary of the steering wheel angle, This is the lower boundary influence factor of the steering wheel angle range. This is the influence factor for the upper boundary of the steering wheel angle range; The specific calculation formula for the steering wheel angle range influencing factor is as follows: in, This represents the lower limit of the influencing factor on the range of steering wheel angle. This represents the upper limit of the influencing factor on the steering wheel angle range. The factor influencing the maximum absolute value of the steering wheel angle. The influencing factor is the steering wheel angular velocity. The lower limit of the range is affected by the maximum absolute value of the steering wheel angle. The lower limit of the range is determined by the influence of steering wheel angular velocity on the weight. The maximum absolute value of the steering wheel angle affects the weighting of the upper limit range. The upper limit of the range is affected by the steering wheel angular velocity. Select according to specific needs, and , , , , .

4. The method for dividing the variable angle transmission ratio speed angle boundary based on driver style according to claim 1, characterized in that, The driver style recognition model is constructed using a semi-supervised support vector machine algorithm, which can classify drivers into cautious, average, and aggressive types. The driver style factor When the driver is identified as cautious When the driver is identified as a general type When the driver is identified as aggressive ; The environmental impact factors The calculation formula is as follows: in, As an environmental impact factor, The road surface adhesion coefficient, , Traffic density, This refers to the road surface adhesion coefficient and reinforcement coefficient. , The traffic density attenuation coefficient is... , This is the half-saturation adjustment coefficient for traffic flow density. , This is the traffic density index coefficient. ; Traffic density This refers to the number of vehicles per unit road length, expressed in vehicles / km. The driver speed influence factor The calculation formula is as follows: in, As a factor affecting driver speed, For drivers to identify highway boundaries, Identify the low-speed dividing line for drivers. , For driver style factors, The high-speed boundary line affects the weighting. The low-speed dividing line affects the weight. The driver style influences the weighting. , This is the normalization coefficient for the deviation of the high-speed boundary line. , This is the normalization coefficient for the low-speed boundary deviation. ; The driver identified the highway dividing line This refers to the speed boundary value, expressed in km / h, that a driver subjectively considers when transitioning from a medium-speed to a high-speed driving state, based on their driving experience, vehicle handling feel, and road traffic conditions. At that time, the driver believes the vehicle has not yet entered a high-speed driving state; when the vehicle's speed is greater than or equal to... At that time, the driver believed that the vehicle was gradually moving from a medium speed to a high speed. The driver identified the low-speed dividing line. This refers to the speed boundary value, expressed in km / h, that a driver subjectively considers when transitioning from a low-speed to a medium-speed driving state, based on their driving experience, vehicle handling feel, and road traffic conditions. At that time, the driver believes the vehicle is traveling at a low speed; when the vehicle's speed exceeds a certain threshold... At that time, the driver believed that the vehicle was gradually moving from a low speed to a medium speed. The influence factor of the maximum absolute value of the steering wheel angle The calculation formula is as follows: in, For driver comfort steering angle threshold, The driver's habitual maximum steering input angle, The upper boundary of the steering wheel angle. The maximum absolute value of the steering wheel angle. The average absolute value of the steering wheel angle. The steering input percentage is the baseline value. The average duration of the driver's steering action. This serves as a baseline value for the duration of the steering maneuver. , The weighting of the comfort steering angle threshold is determined by the following factors. The weighting is determined by the influence of the habitual maximum steering input angle. The actual maximum steering input angle influences the weight. The weighting is determined by the proportion of input usage used in the shift. The duration of the steering action affects the weighting. , Normalized scale for comfort steering angle deviation , The normalized scale is the habitual maximum steering input angle deviation. , The normalized scale is the actual maximum steering input angle deviation. , As a normalized scale for the deviation of the steering input ratio, , The normalized scale for the deviation in steering action duration. , For a very small correction amount, ; The driver's habitual maximum steering input angle This is the statistical maximum value of the absolute value of the steering wheel angle in the driver's historical driving data, used to characterize the maximum steering wheel angle input amplitude that the driver is accustomed to using during normal driving. The driver comfort steering angle threshold The easy steering angle value is the driver's subjective perception of the upper limit of the steering wheel angle that the driver can accept without significantly increasing the handling burden. It can be obtained through driver subjective evaluation, driving simulator calibration test and historical steering data statistics. The average duration of the driver's steering action The average duration from the start to the end of a valid steering action during a driver's historical driving test is used to characterize the driver's continuous steering input habit, and is measured in seconds. The steering wheel angular velocity influencing factor The calculation formula is as follows: in, For driver comfort steering angular velocity threshold, The driver's habitual maximum steering angular velocity, The upper boundary of the basic steering wheel angular velocity. This is the actual maximum steering wheel angular velocity. This represents the actual average steering wheel angular velocity. The root mean square of the acceleration due to the steering wheel angle is... Use the percentage reference value for steering angular velocity. , As a benchmark value for the degree of abrupt change in direction, , The weighting of the comfort steering angular velocity threshold influences the following: The weighting is determined by the influence of the habitual maximum steering angular velocity. The actual maximum steering angular velocity influences the weight. The weighting of the percentage of steering angular velocity used affects the overall weighting. To suppress the degree of shift mutation, , To normalize the deviation of steering angle rate for comfort, , The normalized scale for the habitual maximum steering angular velocity deviation is... , The normalized scale for the actual maximum steering angular velocity deviation. , The percentage deviation normalization scale is used for the steering angular velocity. , As a normalized scale for the degree of deviation of the shift, ; The driver's habitual maximum steering angular velocity This represents the maximum absolute value of the steering wheel angular velocity in the driver's historical driving data, used to characterize the driver's habitual steering operation speed.

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