阅读说明：本技术 汽车直线行驶能力鲁棒性控制系统及其控制方法 (Automobile straight-line driving capability robustness control system and control method thereof ) 是由 艾洋 左厚琼 陈智磊 杨建园 马东 于 2021-06-07 设计创作，主要内容包括：本发明公开了一种汽车直线行驶能力鲁棒性控制系统,包括参数获取模块、参数处理模块、控制器、主动回正模块。本发明还公开了一种汽车直线行驶能力鲁棒性控制系统的控制方法,通过获取转向管柱相对转角和车辆的运行参数确定方向盘修正转角和方向盘修正转角偏差,求得方向盘相对转角并判断车辆是否处于直行状态,当车辆处于直线行驶状态时关闭主动回正模块,并通过摩擦补偿模块调节转向系统的摩擦力矩,进一步地抵抗车辆直行时外界因素对车辆的影响,从而提高了车辆直线行驶能力的鲁棒性。(The invention discloses a system for controlling the robustness of the straight-line driving capability of an automobile, which comprises a parameter acquisition module, a parameter processing module, a controller and an active correction module. The invention also discloses a control method of the robustness control system for the straight-line driving capability of the automobile, which comprises the steps of determining the correction corner of a steering wheel and the deviation of the correction corner of the steering wheel by obtaining the relative corner of a steering column and the running parameters of the automobile, obtaining the relative corner of the steering wheel, judging whether the automobile is in a straight-line state or not, closing an active aligning module when the automobile is in the straight-line driving state, adjusting the friction torque of a steering system through a friction compensation module, and further resisting the influence of external factors on the automobile when the automobile is in the straight-line state, thereby improving the robustness of the straight-line driving capability of the automobile.)

1. A car straight line driving ability robustness control system which characterized in that: the device comprises a parameter acquisition module (100), a parameter processing module (200), a controller (300) and an active alignment module (400);

the parameter acquisition module (100) is used for acquiring the relative rotation angle delta alpha of the steering column, the vehicle speed S and the transverse acceleration a_yAnd an understeer gradient ξ;

the parameter processing module (200) is used for determining a steering wheel correction corner beta and a steering wheel correction corner deviation delta according to the relative steering angle of the steering column, the vehicle speed, the transverse acceleration and the understeer gradient;

the controller (300) is used for judging that when the corrected steering wheel angle beta is positioned at a corrected steering wheel angle threshold value beta 0 +/-a corrected steering wheel angle deviation threshold value delta 0 and the corrected steering wheel angle deviation delta is smaller than or equal to the corrected steering wheel angle deviation threshold value delta 0, the relative steering wheel angle theta at the current moment is output as the sum of the relative steering column angle delta alpha and the corrected steering wheel angle beta at the current moment;

and a controller for judging whether the corrected steering wheel angle is not at the corrected steering wheel angle threshold β 0 ± the corrected steering wheel angle deviation threshold Δ 0 or whether the corrected steering wheel angle deviation Δ is greater than the corrected steering wheel angle deviation threshold Δ 0, and outputting the relative steering wheel angle at the current time as the sum of the relative steering column angle and the corrected steering wheel angle at the previous time, wherein the corrected steering wheel angle deviation threshold Δ 0 includes a fixed steering wheel angle deviation threshold Δ 0';

the system is used for judging whether the vehicle is in a straight-going state or not according to the relative steering wheel rotation angle theta at the current moment;

and the active aligning module (400) is used for actively executing steering wheel aligning to enable the vehicle to be in a straight-going state when the vehicle does not meet the straight-going state.

2. The automotive straight-driving capability robustness control system according to claim 1, characterized in that: the parameter processing module (200) is further configured to derive the steering wheel correction turning angle β with respect to time and then correct the steering wheel correction turning angle β to obtain a steering wheel correction turning angle deviation Δ.

3. The automotive straight-driving capability robustness control system according to claim 1, characterized in that: the controller (300) is further configured to determine to turn off the active return-to-positive module (400) if the absolute value | θ | of the relative steering angle of the steering wheel at the current time is less than or equal to the relative steering angle threshold θ'.

4. The automotive straight-driving capability robustness control system according to claim 1, characterized in that: the controller (300) is further configured to output the steering wheel correction corner threshold as the steering wheel correction corner at the previous moment and output the steering wheel correction corner threshold as the steering wheel correction corner deviation at the previous moment in a process from vehicle power-on to first satisfaction that the steering wheel correction corner is located at the steering wheel correction corner threshold ± the steering wheel correction corner deviation fixed threshold, and the steering wheel correction corner deviation is smaller than or equal to the steering wheel correction corner deviation fixed threshold.

5. The automotive straight-driving capability robustness control system according to claim 1, characterized in that: and the controller (300) is also used for outputting the steering wheel correction corner threshold value as the steering wheel correction corner at the previous moment when the steering wheel correction corner is positioned at the steering wheel correction corner threshold value +/-steering wheel correction corner deviation fixed threshold value and the steering wheel correction corner deviation is smaller than or equal to the steering wheel correction corner deviation fixed threshold value, and keeping the steering wheel correction corner deviation threshold value unchanged.

6. The automotive straight-driving capability robustness control system according to claim 1, characterized in that: a friction compensation module (500) is also included, the friction compensation module (500) being configured to adjust a friction torque of the steering system.

7. The automotive straight-driving capability robustness control system according to claim 6, characterized in that: the controller (300) is further used for judging that when the relative rotation angle of the steering wheel is smaller than or equal to the set value of the relative rotation angle of the steering wheel, the friction compensation module (500) is controlled to increase the friction torque of the steering system.

8. The automotive straight-driving capability robustness control system according to claim 6, characterized in that: the controller (300) is further used for judging that when the relative rotation angle of the steering wheel is larger than the set value of the relative rotation angle of the steering wheel, the friction compensation module (500) is controlled to reduce the friction torque of the steering system.

9. The control method of the robust control system for the straight-driving ability of the automobile according to claims 1 to 8, comprising:

obtaining the relative rotation angle delta alpha, the vehicle speed S and the transverse acceleration a of the steering column_yAnd understeer gradient xi, and determining a corrected steering wheel angle beta and a corrected steering wheel angle deviation delta according to the acquired parameters;

when the corrected steering wheel angle beta is positioned at a corrected steering wheel angle threshold value beta 0 +/-a corrected steering wheel angle deviation threshold value delta 0 and the corrected steering wheel angle deviation delta is smaller than or equal to the corrected steering wheel angle deviation threshold value delta 0, outputting the relative steering wheel angle theta at the current moment as the sum of the relative steering column angle delta alpha and the corrected steering wheel angle beta at the current moment;

when the corrected steering wheel angle is not located at the corrected steering wheel angle threshold value beta 0 +/-the corrected steering wheel angle deviation threshold value delta 0 or the corrected steering wheel angle deviation delta is larger than the corrected steering wheel angle deviation threshold value delta 0, outputting the relative steering wheel angle at the current moment as the sum of the relative steering column angle and the corrected steering wheel angle at the previous moment;

and judging whether the vehicle is in a straight-going state or not according to the relative steering wheel rotation angle theta at the current moment, and if the vehicle is in the straight-going state, not executing the active correction function.

10. The control method of the robustness control system for straight-driving ability of an automobile according to claim 9, wherein: when the relative rotation angle of the steering wheel is smaller than or equal to the set value of the relative rotation angle of the steering wheel, reducing the friction torque of a steering system; and when the relative rotation angle of the steering wheel is larger than the set value of the relative rotation angle of the steering wheel, the friction torque of the steering system is increased.

Technical Field

The invention relates to the technical field of automobile steering control, in particular to an automobile straight-line driving capability robustness control system and a control method thereof.

Background

The straight-line driving capability of the vehicle is influenced by multiple factors, firstly, the mechanical structural factors of the vehicle, such as the manufacturing deviation of the vehicle, the positioning deviation of four wheels, the taper force of left and right tires, the axial force distribution of left and right springs, the load distribution and the like, secondly, the active return function of the steering system EPS is involved, and in addition, the capability of the vehicle for maintaining straight-line driving is influenced by uneven external road surface, crosswind and the like. The increased manufacturing tolerances of the machine parts increase the ability of the vehicle to maintain straight line travel, but also directly increase manufacturing costs.

Chinese patent application CN106470889B discloses a safe and good steering feeling electric power steering apparatus having a function of suppressing lateral shift or lateral shift so as to obtain an effect of reducing the load on the driver during lateral shift or lateral shift. The electric power steering device is provided with a motor current correction value calculation means for correcting the current command value by a motor current correction value based on a motor correction signal, the motor current correction value calculation means is composed of a straight-line running state determination means for determining a straight-line running state of the vehicle, an adaptive calculation means for calculating and outputting a motor correction signal based on at least a straight-line running determination result, a steering angle, and an acting force, a vehicle speed induction gain means for outputting a vehicle speed gain corresponding to a vehicle speed, and an output calculation means for multiplying the vehicle speed gain by the motor correction signal and outputting a motor current correction value, the motor correction signal and the steering information are subjected to threshold value setting and condition judgment of the motor correction signal and the steering information and the threshold value, so that the function of deviation from lateral deviation suppression or lateral deviation suppression is provided. According to the scheme, the traditional entity steering sensor is adopted, the external interference resistance is improved by increasing the moment through the EPS, the interference of a road and a mechanical part is reduced, the straight-ahead running robustness of the vehicle is improved, and the interference caused by the aligning function of the EPS is not avoided.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a system and a method for controlling the robustness of the straight-line driving capability of an automobile.

In order to achieve the above object, the present invention provides a robust control system for a straight-line driving capability of an automobile, which is characterized in that: the device comprises a parameter acquisition module, a parameter processing module, a controller and an active correction module;

the parameter acquisition module is used for acquiring the relative rotation angle delta alpha, the vehicle speed S and the transverse acceleration a of the steering column_yAnd an understeer gradient xi, wherein the relative rotation angle of the steering column is the difference between the current rotation angle of the steering column and the rotation angle of the steering column when the vehicle is electrified;

the parameter processing module is used for determining a corrected steering wheel angle beta and a corrected steering wheel angle deviation delta according to the relative steering angle of a steering column, the vehicle speed, the transverse acceleration and the understeer gradient, wherein the corrected steering wheel angle is the difference between a zero-bit steering wheel angle and the steering wheel angle when the vehicle is in a straight-ahead state, and the corrected steering wheel angle deviation is the change rate of the corrected steering wheel angle;

the controller is used for judging that when the steering wheel correction corner beta is located at a steering wheel correction corner threshold value beta 0 +/-a steering wheel correction corner deviation threshold value delta 0 and the steering wheel correction corner deviation delta is smaller than or equal to the steering wheel correction corner deviation threshold value delta 0, the steering wheel relative corner theta at the current moment is output as the sum of the steering column relative corner delta alpha and the steering wheel correction corner beta at the current moment, and the steering wheel relative corner theta is the difference between the steering wheel corner at the current moment and the steering wheel corner when the vehicle is in a straight-ahead state;

and a controller for judging whether the corrected steering wheel angle is not at the corrected steering wheel angle threshold β 0 ± the corrected steering wheel angle deviation threshold Δ 0 or whether the corrected steering wheel angle deviation Δ is greater than the corrected steering wheel angle deviation threshold Δ 0, and outputting the relative steering wheel angle at the current time as the sum of the relative steering column angle and the corrected steering wheel angle at the previous time, wherein the corrected steering wheel angle deviation threshold Δ 0 includes a fixed steering wheel angle deviation threshold Δ 0';

the system is used for judging whether the vehicle is in a straight-going state or not according to the relative steering wheel rotation angle theta at the current moment;

and the active aligning module is used for actively executing steering wheel aligning to enable the vehicle to be in a straight-going state when the vehicle does not meet the straight-going state.

Further, the parameter processing module is used for obtaining the corrected steering wheel rotation angle beta through the following formula

Wherein the content of the first and second substances,for the steering system gear ratio, L is the vehicle wheelbase.

Further, the parameter processing module is further configured to derive the steering wheel correction angle β with respect to time and then multiply the time by the correction coefficient λ to obtain the steering wheel correction angle deviation Δ.

Further, the controller is further configured to determine to turn off the active return module if the absolute value | θ | of the relative rotation angle of the steering wheel at the current time is less than or equal to the threshold value θ' of the relative rotation angle of the steering wheel.

Further, the controller is further configured to, during a period from power-on of the vehicle to a time when the first satisfaction of the steering wheel correction turn angle is located at the steering wheel correction turn angle threshold ± the steering wheel correction turn angle deviation fixed threshold, and the steering wheel correction turn angle deviation is smaller than or equal to the steering wheel correction turn angle deviation fixed threshold, output the steering wheel correction turn angle threshold as the steering wheel correction turn angle at the previous time, and output the steering wheel correction turn angle deviation threshold as the steering wheel correction turn angle deviation at the previous time.

Further, the controller is further configured to output the steering wheel correction turning angle threshold as the steering wheel correction turning angle at the previous time when the steering wheel correction turning angle is located at the steering wheel correction turning angle threshold ± the steering wheel correction turning angle deviation fixed threshold and the steering wheel correction turning angle deviation is smaller than or equal to the steering wheel correction turning angle deviation fixed threshold, and keep the steering wheel correction turning angle deviation threshold unchanged.

Further, the device also comprises a friction compensation module, wherein the friction compensation module is used for adjusting the friction torque of the steering system.

Further, the controller is further configured to determine that the friction compensation module is controlled to increase the friction torque of the steering system when the relative rotation angle of the steering wheel is less than or equal to a set value of the relative rotation angle of the steering wheel.

Further, the controller is further used for judging that when the relative rotation angle of the steering wheel is larger than the set value of the relative rotation angle of the steering wheel, the friction compensation module is controlled to reduce the friction torque of the steering system.

The invention also provides a control method of the automobile straight-line driving capability robustness control system, which comprises the following steps:

obtaining the relative rotation angle delta alpha, the vehicle speed S and the transverse acceleration a of the steering column_yAnd understeer gradient xi, and determining a corrected steering wheel angle beta and a corrected steering wheel angle deviation delta according to the acquired parameters;

when the corrected steering wheel angle beta is positioned at a corrected steering wheel angle threshold value beta 0 +/-a corrected steering wheel angle deviation threshold value delta 0 and the corrected steering wheel angle deviation delta is smaller than or equal to the corrected steering wheel angle deviation threshold value delta 0, outputting the relative steering wheel angle theta at the current moment as the sum of the relative steering column angle delta alpha and the corrected steering wheel angle beta at the current moment;

when the corrected steering wheel angle is not located at the corrected steering wheel angle threshold value beta 0 +/-the corrected steering wheel angle deviation threshold value delta 0 or the corrected steering wheel angle deviation delta is larger than the corrected steering wheel angle deviation threshold value delta 0, outputting the relative steering wheel angle at the current moment as the sum of the relative steering column angle and the corrected steering wheel angle at the previous moment;

and judging whether the vehicle is in a straight-going state or not according to the relative steering wheel rotation angle theta at the current moment, and if the vehicle is in the straight-going state, not executing the active correction function.

Further, when the relative rotation angle of the steering wheel is smaller than or equal to the set value of the relative rotation angle of the steering wheel, the friction torque of the steering system is reduced; and when the relative rotation angle of the steering wheel is larger than the set value of the relative rotation angle of the steering wheel, the friction torque of the steering system is increased.

The invention has the beneficial effects that: and the robustness of the straight-ahead driving capability of the vehicle is improved. On the basis of omitting a steering wheel corner sensor, the relative corner of a steering column is obtained by obtaining the rotation angle of a steering column motor after a vehicle is electrified, then the corrected corner of the steering wheel and the corrected corner deviation of the steering wheel are determined according to the running parameters of the vehicle, whether the corrected corner of the steering wheel at the moment is acceptable or not is judged, if the corrected corner of the steering wheel at the moment is not acceptable, the corrected corner of the steering wheel at the last moment is output, the corrected corner threshold value of the steering wheel and the corrected corner deviation threshold value of the steering wheel are updated, and a standard is provided for judging whether the corrected corner of the steering wheel at the next moment is acceptable or not; the sum of the relative rotation angle of the steering column and the corrected rotation angle of the steering wheel is obtained as the relative rotation angle of the steering wheel, and when the relative rotation angle of the steering wheel meets the condition that the vehicle is in a straight running state, the active aligning module is closed, so that the active aligning module is prevented from being automatically started when the relative rotation angle of the steering wheel is inconsistent with the zero position angle of the steering wheel, and the influence on the straight running state of the vehicle is avoided; meanwhile, the friction torque of the steering system is adjusted through the friction compensation module, and the influence of external factors on the vehicle when the vehicle moves straight is further resisted, so that the robustness of the straight-line driving capability of the vehicle is improved.

Drawings

FIG. 1 is a schematic diagram of a control system according to the present invention.

The components in the figures are numbered as follows: the system comprises a parameter acquisition module 100, a parameter processing module 200, a controller 300, an active return module 400, and a friction compensation module 500.

Detailed Description

The following detailed description is provided to further explain the claimed embodiments of the present invention in order to make it clear for those skilled in the art to understand the claims. The scope of the invention is not limited to the following specific examples. It is intended that the scope of the invention be determined by those skilled in the art from the following detailed description, which includes claims that are directed to this invention.

As shown in fig. 1, the system for controlling robustness of straight-line driving capability of an automobile comprises a parameter obtaining module 100, a parameter processing module 200, a controller 300 and an active return module 400.

A parameter acquisition module 100 for acquiring the relative rotation angle delta alpha, the vehicle speed S and the transverse acceleration a of the steering column_yAnd the steering gradient xi is not changed, the relative rotation angle of the steering column is the difference between the current rotation angle of the steering column and the rotation angle of the steering column when the vehicle is electrified, and the current rotation angle of the steering column and the rotation angle of the steering column when the vehicle is electrified are unknown quantities. In the embodiment, a steering wheel angle sensor is omitted, and the relative angle of the steering column is obtained by obtaining the relative angle of the electrified steering column motor, so that the relative angle of the steering wheel is indirectly solved. In this embodiment, the steering column angle at the present time is equal to the steering wheel angle and also equal to the wheel angle, so that it is default that there is no deviation in the steering transmission process from the steering wheel to the steering column and then to the wheels, and when the vehicle is in a straight-ahead state, the reason why the steering wheel angle and the steering column angle are both non-zero is the unevenness of the road surface and external objective factors such as vehicle turning.

A parameter processing module 200 for processing the lateral acceleration a according to the relative steering column rotation angle delta alpha, the vehicle speed S and the lateral acceleration_yAnd determining a steering wheel correction steering angle beta and a steering wheel correction steering angle deviation delta by the understeer gradient xi, wherein the steering wheel correction steering angle is the difference between the steering wheel zero angle and the steering wheel steering angle when the vehicle is in a straight-ahead driving state, and the steering wheel correction steering angle deviation is the change rate of the steering wheel correction steering angle.

In this embodiment, the parameter processing module 200 is configured to obtain the corrected steering wheel rotation angle β according to the following formula

Wherein the content of the first and second substances,for the steering system gear ratio, L is the vehicle wheelbase and the understeer gradient ξ is the understeer rate of change.

In this embodiment, the parameter processing module 200 is further configured to derive the steering wheel correction angle β with respect to time, and then multiply the steering wheel correction angle β by the correction coefficient λ to obtain the steering wheel correction angle deviation Δ, where the correction coefficient is a fixed value and has a unit s, and the unit of angular velocity may be converted into an angle unit.

And a controller 300 configured to determine that the steering wheel correction angle β at the current time is acceptable when the steering wheel correction angle β is located at the steering wheel correction angle threshold β 0 ± the steering wheel correction angle deviation threshold Δ 0 and the steering wheel correction angle deviation Δ is less than or equal to the steering wheel correction angle deviation threshold Δ 0, output the steering wheel relative angle θ at the current time as a sum of the steering column relative angle Δ α and the steering wheel correction angle β at the current time, and output the steering wheel relative angle θ as a difference between the steering wheel angle at the current time and the steering wheel angle when the vehicle is in a straight-ahead state.

The controller 300 is further configured to determine that when the corrected steering wheel angle is not located at the corrected steering wheel angle threshold β 0 ± the corrected steering wheel angle deviation threshold Δ 0 or when the corrected steering wheel angle deviation Δ is greater than the corrected steering wheel angle deviation threshold Δ 0, the corrected steering wheel angle β at the current time is relatively large and unacceptable, and output the relative steering wheel angle at the current time as the sum of the relative steering column angle Δ α and the corrected steering wheel angle at the previous time, where the corrected steering wheel angle deviation threshold Δ 0 includes a fixed steering wheel angle deviation threshold Δ 0'.

The controller 300 is further configured to determine that the vehicle is in a straight-driving state and turn off the active return module 400 if the absolute value | θ | of the relative steering angle of the steering wheel at the current time is less than or equal to the relative steering angle threshold θ'. In theory, no matter whether the steering wheel is at the steering wheel zero position angle, when the steering wheel relative rotation angle is 0, the vehicle is in the straight running state, but in practice, the vehicle can be basically considered to be in the straight running state as long as the steering wheel relative rotation angle is changed within a small range close to 0, and therefore, the steering wheel relative rotation angle threshold value is a small value. The reason why the relative steering wheel angle is used for the determination is that if the vehicle is determined to be in a straight-ahead state when the steering wheel angle is close to 0 according to the prior art, it may occur that if the steering wheel angle is not close to 0 when the vehicle is in the straight-ahead state, the active return-to-normal function is activated at this time according to the setting in the prior art, and the vehicle may not be kept straight instead.

And the active aligning module 400 is used for actively executing steering wheel aligning to enable the vehicle to be in a straight running state when the vehicle does not meet the straight running state.

In this embodiment, the controller 300 is further configured to output the steering wheel correction angle threshold as the steering wheel correction angle at the previous time and output the steering wheel correction angle deviation threshold as the steering wheel correction angle deviation at the previous time in a process from the vehicle power-on to the first satisfaction that the steering wheel correction angle β is located at the steering wheel correction angle threshold β 0 ± the steering wheel correction angle deviation fixed threshold Δ 0 'and the steering wheel correction angle deviation Δ is smaller than or equal to the steering wheel correction angle deviation fixed threshold Δ 0'. In this way, because the relative steering angle of the steering wheel at the time of powering on the vehicle often does not satisfy the vehicle straight-ahead state, it is necessary to determine the steering wheel correction steering angle threshold value when the vehicle is in the execution state by quickly updating, and to continuously reduce the steering wheel correction steering angle deviation threshold value, thereby improving the reliability of the calculation of the steering wheel correction steering angle.

In this embodiment, the controller 300 is further configured to output the steering wheel correction turning angle threshold as the steering wheel correction turning angle at the previous time when the steering wheel correction turning angle β is not located at the steering wheel correction turning angle threshold β 0 ± the steering wheel correction turning angle deviation fixed threshold Δ 0 ' or when the steering wheel correction turning angle deviation Δ is greater than the steering wheel correction turning angle deviation fixed threshold Δ 0 ', and keep the steering wheel correction turning angle deviation threshold unchanged as the steering wheel correction turning angle deviation fixed threshold Δ 0 '. In this case, the steering wheel correction angle threshold value needs to be changed in accordance with the steering wheel correction angle, but since the vehicle is considered to be in a substantially straight-driving state, the steering wheel correction angle deviation threshold value does not need to be updated.

In this embodiment, a friction compensation module 500 is further included, and the friction compensation module 500 is used for adjusting the friction torque of the steering system.

In this embodiment, the controller 300 is further configured to determine that the friction compensation module 500 is controlled to increase the friction torque of the steering system when the relative rotation angle of the steering wheel is less than or equal to the set relative rotation angle of the steering wheel. Because the vehicle approaches a straight-driving state when the relative rotation angle of the steering wheel is smaller, in order to maintain the straight-driving capability of the vehicle, the interference of the external road condition on the vehicle is resisted by increasing the friction torque of the steering system.

In this embodiment, the controller 300 is further configured to determine that the friction compensation module 500 is controlled to reduce the friction torque of the steering system when the relative rotation angle of the steering wheel is greater than the set value of the relative rotation angle of the steering wheel. In this case, the more the vehicle deviates from the straight-traveling state, the less the ability of the vehicle to travel straight is required to be maintained, and therefore, the friction torque of the steering system needs to be reduced.

The control method of the automobile straight-line driving capability robustness control system comprises the following steps:

1. the parameter acquisition module acquires the relative rotation angle delta alpha, the vehicle speed S and the transverse acceleration a of the steering column_yAnd an understeer gradient xi, the parameter processing module determines a corrected steering wheel angle beta and a corrected steering wheel angle deviation delta according to the acquired parameters, and the corrected steering wheel angle is the difference between the steering wheel angle and the steering wheel zero-bit angle in a straight running state.

2. When the vehicle is powered on and the controller judges that the first satisfied steering wheel corrected corner beta is located at a steering wheel corrected corner threshold beta 0 +/-a steering wheel corrected corner deviation fixed threshold delta 0 'and the steering wheel corrected corner deviation delta is smaller than or equal to the steering wheel corrected corner deviation fixed threshold delta 0', the first steering wheel corrected corner threshold beta 0 is set to be 0, the first steering wheel corrected corner deviation threshold delta 0 is positive infinity, the output steering wheel corrected corner threshold is the steering wheel corrected corner at the previous moment, and the output steering wheel corrected corner deviation threshold is the steering wheel corrected corner deviation at the previous moment. In this stage, the corrected steering wheel angle threshold and the corrected steering wheel angle deviation threshold are continuously updated until the corrected steering wheel angle deviation threshold is updated to the corrected steering wheel angle deviation fixed threshold, and then the next stage is started.

3. And when the corrected steering wheel angle beta is positioned at a corrected steering wheel angle threshold beta 0 +/-a fixed steering wheel angle deviation threshold delta 0 'and the corrected steering wheel angle deviation delta is smaller than or equal to the fixed steering wheel angle deviation threshold delta 0', outputting the corrected steering wheel angle threshold as the corrected steering wheel angle at the previous moment, and keeping the fixed steering wheel angle deviation threshold unchanged.

In the above steps 2 and 3, when the steering wheel correction angle β is located at the steering wheel correction angle threshold β 0 ± the steering wheel correction angle deviation threshold Δ 0 and the steering wheel correction angle deviation Δ is smaller than or equal to the steering wheel correction angle deviation threshold Δ 0, outputting the steering wheel relative angle θ at the current time as the sum of the steering column relative angle Δ α and the steering wheel correction angle β at the current time, and the steering wheel relative angle as the difference between the steering wheel angle and the steering wheel angle in the straight traveling state;

in the above step 2 and step 3, when the corrected steering wheel angle is not located at the corrected steering wheel angle threshold β 0 ± the corrected steering wheel angle deviation threshold Δ 0 or the corrected steering wheel angle deviation Δ is greater than the corrected steering wheel angle deviation threshold Δ 0, outputting the steering wheel relative angle at the current time as the sum of the steering column relative angle and the steering wheel corrected angle at the previous time;

4. if the absolute value | theta | of the relative rotation angle of the steering wheel at the current moment is less than or equal to the relative rotation angle threshold theta', the vehicle is judged to be in a straight-ahead state, and the active aligning module 400 is closed; if the vehicle is not in the execute state, the active return module 400 is turned on.

Meanwhile, when the relative rotation angle of the steering wheel is smaller than or equal to the set value of the relative rotation angle of the steering wheel, the friction torque of the steering system is reduced; and when the relative rotation angle of the steering wheel is larger than the set value of the relative rotation angle of the steering wheel, the friction torque of the steering system is increased.

On the basis of omitting a steering wheel corner sensor, the relative corner of a steering column is obtained by obtaining the rotation angle of a steering column motor after a vehicle is electrified, then the corrected corner of the steering wheel and the corrected corner deviation of the steering wheel are determined according to the running parameters of the vehicle, whether the corrected corner of the steering wheel at the moment is acceptable or not is judged, if the corrected corner of the steering wheel at the moment is not acceptable, the corrected corner of the steering wheel at the last moment is output, the corrected corner threshold value of the steering wheel and the corrected corner deviation threshold value of the steering wheel are updated, and a standard is provided for judging whether the corrected corner of the steering wheel at the next moment is acceptable or not; the sum of the relative rotation angle of the steering column and the corrected rotation angle of the steering wheel is obtained as the relative rotation angle of the steering wheel, and when the relative rotation angle of the steering wheel meets the condition that the vehicle is in a straight running state, the active aligning module is closed, so that the active aligning module is prevented from being automatically started when the relative rotation angle of the steering wheel is inconsistent with the zero position angle of the steering wheel, and the influence on the straight running state of the vehicle is avoided; meanwhile, the friction torque of the steering system is adjusted through the friction compensation module, and the influence of external factors on the vehicle when the vehicle moves straight is further resisted, so that the robustness of the straight-line driving capability of the vehicle is improved.