阅读说明：本技术 车辆稳定性控制系统及方法 (Vehicle stability control system and method ) 是由 李春善 王宇 张建 侯殿龙 徐丹琳 周添 于 2021-09-22 设计创作，主要内容包括：本申请实施例公开了一种车辆稳定性控制系统。该系统包括：稳定性约束模块,根据目标时间段内的预测环境信息确定车辆后轮的控制层约束数据和执行层约束数据；反馈控制模块,根据控制层约束数据和/或执行层约束数据,确定后轮转向反馈控制数据；前馈控制模块,根据车辆的行驶信息确定后轮转向前馈控制数据；后轮转角确定模块,根据后轮转向反馈控制数据和后轮转向前馈控制数据确定后轮的第一转角数据,以及根据车辆的行驶信息确定的第二转角数据,确定目标转角数据；执行控制模块,基于目标转角数据,控制车辆后轮的转向操作。该系统通过设置约束数据使车辆在行驶过程中车辆的横摆角速度等特性不会产生过大的偏差,保证了车辆的稳定性。(The embodiment of the application discloses a vehicle stability control system. The system comprises: the stability constraint module is used for determining control layer constraint data and execution layer constraint data of the rear wheels of the vehicle according to the predicted environment information in the target time period; the feedback control module determines rear wheel steering feedback control data according to the control layer constraint data and/or the execution layer constraint data; the feed-forward control module determines the rear wheel feed-forward control data according to the running information of the vehicle; the rear wheel steering angle determining module is used for determining first steering angle data of rear wheels according to the rear wheel steering feedback control data and the rear wheel steering feedforward control data and determining target steering angle data according to second steering angle data determined by the running information of the vehicle; and the execution control module controls the steering operation of the rear wheels of the vehicle based on the target turning angle data. The system ensures that the characteristics of the vehicle such as the yaw velocity and the like do not generate overlarge deviation in the running process of the vehicle by setting the constraint data, and ensures the stability of the vehicle.)

1. A vehicle stability control system, the system comprising:

the stability constraint module is used for determining control layer constraint data and execution layer constraint data of the rear wheels of the vehicle according to the predicted environment information in the target time period;

the feedback control module is used for determining rear wheel steering feedback control data according to the control layer constraint data and/or the execution layer constraint data;

the feed-forward control module is used for determining rear wheel feed-forward control data according to the running information of the vehicle;

the rear wheel steering angle determining module is used for determining first steering angle data of the rear wheels according to the rear wheel steering feedback control data and the rear wheel steering feedforward control data, and determining target steering angle data according to second steering angle data determined by the running information of the vehicle;

and the execution control module is used for controlling the steering operation of the rear wheels of the vehicle based on the target steering angle data.

2. The system of claim 1, wherein the stability constraint module comprises:

the control layer constraint data determining unit is used for determining at least one of running path deviation constraint data, yaw rate deviation constraint data and centroid side deviation constraint data;

and the execution layer constraint data determining unit is used for determining the rear wheel steering angle limit constraint and/or the rear wheel steering angle change rate constraint.

3. The system of claim 1, further comprising:

the vehicle stability control system comprises an environment information input module, a vehicle stability control module and a vehicle stability control module, wherein the environment information input module is used for acquiring environment information and inputting the environment information to the vehicle stability control system, and the environment information comprises at least one of map information, weather information, terrain information and track information;

and the environment information decision module is used for receiving the environment information input by the environment information input module and determining the predicted environment information in the target time period according to the environment information.

4. The system of claim 1, further comprising:

and the running information input module is used for acquiring the running information of the vehicle and inputting the running information to the feedforward control module.

5. The system of claim 1, further comprising:

and the second corner data determining module is used for determining a corner proportion curve according to the vehicle speed and a two-dimensional interpolation table of the steering wheel corner, and determining second corner data according to the driving information and the corner proportion curve.

6. The system of claim 1, wherein the rear wheel steering angle determination module comprises:

the first turning angle data determining unit is used for superposing the rear wheel steering feedback control data and the rear wheel steering feedforward control data to determine first turning angle data of the rear wheels;

and the weighting calculation unit is used for performing weighted summation on the first rotation angle data and the second rotation angle data to determine target rotation angle data.

7. The system of claim 1, wherein the execution control module comprises:

an actual turning angle determination unit for determining actual turning angle data of the rear wheels of the vehicle;

and the difference value calculating unit is used for calculating the difference value between the actual corner data and the target corner data and controlling the steering operation of the rear wheels of the vehicle according to the difference value.

8. The system according to claim 7, wherein the actual rotation angle determining unit includes:

a rear wheel steering motor position sensor for determining first rack position data;

a rear wheel steering assembly alignment line position sensor for determining second rack position data;

and the actual corner calculating subunit is used for determining actual position data of the rack according to the first rack position data and the second rack position data, and determining actual corner data according to the linear-angular ratio parameter and the actual position data of the rack.

9. The system of claim 1, further comprising:

and the state feedback module is used for acquiring running information of the vehicle after responding to the control of the execution control module and feeding the running information back to the feedforward control module and the feedback control module.

10. A vehicle stability control method, characterized in that the method comprises:

the stability constraint module determines control layer constraint data and execution layer constraint data of rear wheels of the vehicle according to the predicted environment information in the target time period;

the feedback control module determines rear wheel steering feedback control data according to the control layer constraint data and/or the execution layer constraint data;

the feed-forward control module determines the feed-forward control data of the rear wheel according to the driving information of the vehicle;

the rear wheel steering angle determining module determines first steering angle data of rear wheels according to the rear wheel steering feedback control data and the rear wheel steering feedforward control data, and determines target steering angle data according to second steering angle data determined by the running information of the vehicle;

the execution control module controls steering operation of rear wheels of the vehicle based on the target steering angle data.

Technical Field

The embodiment of the application relates to the technical field of automobile steering control, in particular to a system and a method for controlling the stability of a vehicle.

Background

In the case of passenger vehicles, the stability of the vehicle running can be ensured by a slight understeer characteristic, but the problem of oversteer is often generated when the vehicle turns at a high speed. Through the rear wheel steering system, the potential safety hazard caused by excessive steering can be eliminated, and meanwhile, for medium and large-sized vehicles and luxury vehicles, the rear wheel steering system can enable the vehicle to turn at a low speed more flexibly and turn at a high speed more stably.

The rear wheel steering includes two conditions of the rear wheel being in the same direction as the front wheel and the rear wheel being in the opposite direction to the front wheel, and the two conditions may exhibit two completely different steering characteristics. When the vehicle is driven at a low speed, the oversteer can be added appropriately by the reverse operation of the rear wheels and the front wheels. If the vehicle encounters the condition of emergency line change during high-speed driving, the tendency of over-steering is very easy to occur without the help of any electronic auxiliary system, and the tendency of over-steering can be compensated by causing a small but very important steering in the direction similar to that of the front wheels through the rear wheels.

The following method is generally adopted for rear wheel steering control at present: and taking the centroid side slip angle as zero as a control target, determining the rear wheel steering angle gain based on the vehicle speed, and multiplying the steering wheel steering angle by the rear wheel steering angle gain to obtain the rear wheel steering angle feedforward control quantity. The feedback control amount is calculated based on the yaw-rate deviation. And the rear wheel steering angle feedforward control quantity and the rear wheel steering angle feedback control quantity are superposed to form a rear wheel steering angle control quantity for controlling the rear wheel steering. However, in the existing rear wheel steering control technology, control layer constraint and execution layer constraint are not considered, stability control is only performed when the vehicle is in an emergency state, the stability boundary of the vehicle is not pre-judged, and the stability of the vehicle is difficult to guarantee.

Disclosure of Invention

The embodiment of the application provides a vehicle stability control system and method, which can improve the flexibility and stability of a vehicle during turning or line changing.

In a first aspect, an embodiment of the present application provides a vehicle stability control system, which includes:

the stability constraint module is used for determining control layer constraint data and execution layer constraint data of the rear wheels of the vehicle according to the predicted environment information in the target time period;

the feedback control module is used for determining rear wheel steering feedback control data according to the control layer constraint data and/or the execution layer constraint data;

the feed-forward control module is used for determining rear wheel feed-forward control data according to the running information of the vehicle;

the rear wheel steering angle determining module is used for determining first steering angle data of the rear wheels according to the rear wheel steering feedback control data and the rear wheel steering feedforward control data, and determining target steering angle data according to second steering angle data determined by the running information of the vehicle;

and the execution control module is used for controlling the steering operation of the rear wheels of the vehicle based on the target steering angle data.

In a second aspect, an embodiment of the present application provides a vehicle stability control method, which is performed by a vehicle stability control system, and includes:

the stability constraint module determines control layer constraint data and execution layer constraint data of rear wheels of the vehicle according to the predicted environment information in the target time period;

the feedback control module determines rear wheel steering feedback control data according to the control layer constraint data and/or the execution layer constraint data;

the feed-forward control module determines the feed-forward control data of the rear wheel according to the driving information of the vehicle;

the rear wheel steering angle determining module determines first steering angle data of rear wheels according to the rear wheel steering feedback control data and the rear wheel steering feedforward control data, and determines target steering angle data according to second steering angle data determined by the running information of the vehicle;

the execution control module controls steering operation of rear wheels of the vehicle based on the target steering angle data.

The embodiment of the application realizes the control of the steering of the rear wheels of the vehicle through a vehicle stability control system: the system comprises a stability constraint module, a stability analysis module and a stability analysis module, wherein the stability constraint module is used for determining control layer constraint data and execution layer constraint data of rear wheels of a vehicle according to predicted environment information in a target time period; the feedback control module is used for determining rear wheel steering feedback control data according to the control layer constraint data and/or the execution layer constraint data; the feed-forward control module is used for determining rear wheel feed-forward control data according to the running information of the vehicle; the rear wheel steering angle determining module is used for determining first steering angle data of the rear wheels according to the rear wheel steering feedback control data and the rear wheel steering feedforward control data, and determining target steering angle data according to second steering angle data determined by the running information of the vehicle; and the execution control module is used for controlling the steering operation of the rear wheels of the vehicle based on the target steering angle data. The vehicle stability control system provided by the embodiment of the application adjusts the stability boundary in advance by predicting the vehicle running environment information in the future time period, so that the vehicle can adapt to the change of the road surface condition in the future as soon as possible. Meanwhile, the vehicle stability control system ensures that the characteristics of the vehicle such as the yaw velocity and the like do not generate overlarge deviation when the vehicle meets an emergency by setting the constraint data, thereby ensuring the stability of the vehicle.

Drawings

FIG. 1 is a block diagram of a vehicle stability control system provided in an embodiment of the present application;

FIG. 2 is a block diagram of another vehicle stability control system provided in an embodiment of the present application;

FIG. 3 is a flow chart of a method for controlling vehicle stability provided by an embodiment of the present application;

fig. 4 is a block diagram of a structure of another vehicle stability control system provided in an embodiment of the present application.

Detailed Description

The present application is described in further detail below with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the application and are not limiting of the application. It should be further noted that, for the convenience of description, only some of the structures related to the present application are shown in the drawings, not all of the structures.

Fig. 1 is a block diagram of a vehicle stability control system provided in an embodiment of the present application. The technical scheme of the embodiment of the application can be suitable for the scenes of automobile turning or line changing. As shown in fig. 1, the vehicle stability control system provided in the embodiment of the present application may include:

a stability constraint module 110, configured to determine control layer constraint data and execution layer constraint data of a rear wheel of the vehicle according to the predicted environment information in the target time period;

a feedback control module 120, configured to determine rear-wheel steering feedback control data according to the control layer constraint data and/or the execution layer constraint data;

a feedforward control module 130 for determining rear-wheel-forward feedforward control data according to the driving information of the vehicle;

a rear wheel steering angle determination module 140 for determining first steering angle data of the rear wheels based on the rear wheel steering feedback control data and the rear wheel steering feedforward control data, and determining target steering angle data based on second steering angle data determined based on the driving information of the vehicle;

and a control module 150 for controlling the steering operation of the rear wheels of the vehicle based on the target steering angle data.

In the embodiment of the present application, the target time period may be set according to actual requirements, and may be, for example, 10 minutes or half an hour in the future. The environment information may include map information, weather information, terrain information, track information, and road surface information, etc. The map information includes, but is not limited to, road conditions, accident labels, traffic, and the like; weather information includes, but is not limited to, weather, temperature, humidity, wind, etc.; topographic information including, but not limited to, snow, ice, grass, gravel, sand, etc.; the road surface information includes, but is not limited to, the degree of wet skid on the inside, the road surface adhesion coefficient, and the like. The prediction means can be predicted by adopting algorithms such as machine learning and deep learning to build a model, and the embodiment of the application does not limit the prediction means.

The control layer constraint data of the rear wheels of the vehicle refers to a constraint value of a data deviation related to the rear wheels of the vehicle during the driving process, for example, the yaw rate deviation constraint data is 20 degrees, so that when the vehicle has an emergency line change during the driving process, the vehicle stability control system can limit the yaw rate deviation of the vehicle within 20 degrees. The control layer constraint data may be travel path deviation constraint data, yaw rate deviation constraint data, centroid slip angle deviation constraint data, or the like.

The execution layer constraint data of the vehicle rear wheel also refers to a constraint value of related data deviation of the vehicle rear wheel in the driving process, wherein the execution layer constraint data can be rear wheel steering angle limit constraint data, rear wheel steering angle change rate constraint data and the like.

The constraint data can be determined according to the predicted environment information in the target time period, for example, if a strong wind is predicted in the target time period, when the automobile runs at a high speed, the flow field around the automobile body can be changed under the action of a side wind, the symmetry of the flow field is damaged, the pneumatic force and the moment of the automobile are changed, the operation stability and the safety of the automobile are influenced, dangerous behaviors such as yaw, side turning, offset and the like are easy to occur to the automobile, and at the moment, the constraint data of the change rate of the rear wheel angle and the like can be determined to be smaller values so as to reduce the possibility that the automobile has the dangerous behaviors such as side slipping and the like.

In the embodiment of the application, further, the driving path deviation, the yaw rate deviation, the centroid slip angle deviation or one of the driving path deviation, the yaw rate deviation and the centroid slip angle deviation can be used as an optimization target, meanwhile, stability constraints are met, and rear wheel steering feedback control data are obtained through calculation.

In the embodiment of the present application, the running information of the vehicle may be a steering wheel angle, an accelerator pedal opening, a brake pedal opening, and the like. The rear-wheel steering feed-forward control data may be calculated by multiplying one or more pieces of information in the travel information by a rear-wheel steering gain according to an algorithm, for example, multiplying a steering wheel angle by the rear-wheel steering gain as the rear-wheel steering feed-forward control data. The vehicle stability control system can obtain the steering gain of the rear wheel under the steady state through calculation based on a two-degree-of-freedom vehicle model by taking the constant zero mass center slip angle as a control target. When the vehicle is in a low-speed driving state, the rear wheel steering gain is a negative value, and the oversteer is properly added through the reverse operation of the rear wheels and the front wheels; when the vehicle is in a high-speed driving state, the rear wheel steering gain is a positive value, and the rear wheel causes steering in the same direction as the front wheel to compensate for oversteer.

In the embodiment of the present application, the first turning angle data may be obtained by calculating the rear wheel steering feedback control data and the rear wheel steering feedforward control data according to a certain algorithm, for example, by performing weighted summation on the rear wheel steering feedback control data and the rear wheel steering feedforward control data. The second steering angle data may be obtained according to one or more items of information in the driving information, for example, the second steering angle data may be a product of a steering wheel angle in the driving information and a preset ratio, and the preset ratio may be set according to an actual requirement, for example, eighty percent or the like. The target rotation angle data may be obtained by calculating the first rotation angle data and the second rotation angle data according to an algorithm, for example, the first rotation angle data and the second rotation angle data may be weighted and summed to obtain the target rotation angle data.

In the embodiment of the present application, the execution control module 150 controls the steering angle and the direction of the rear wheels of the vehicle based on the target steering angle data.

The embodiment of the application realizes the control of the steering of the rear wheels of the vehicle through a vehicle stability control system: the system comprises a stability constraint module, a stability analysis module and a stability analysis module, wherein the stability constraint module is used for determining control layer constraint data and execution layer constraint data of rear wheels of a vehicle according to predicted environment information in a target time period; the feedback control module is used for determining rear wheel steering feedback control data according to the control layer constraint data and/or the execution layer constraint data; the feed-forward control module is used for determining rear wheel feed-forward control data according to the running information of the vehicle; the rear wheel steering angle determining module is used for determining first steering angle data of the rear wheels according to the rear wheel steering feedback control data and the rear wheel steering feedforward control data, and determining target steering angle data according to second steering angle data determined by the running information of the vehicle; and the execution control module is used for controlling the steering operation of the rear wheels of the vehicle based on the target steering angle data. The vehicle stability control system provided by the embodiment of the application adjusts the stability boundary in advance by predicting the vehicle running environment information in the future time period, so that the vehicle can adapt to the change of the road surface condition in the future as soon as possible. Meanwhile, the vehicle stability control system ensures that data such as yaw velocity and the like do not generate overlarge deviation when the vehicle meets an emergency situation by setting control layer constraint data and execution layer constraint data, and ensures the stability of the vehicle.

In an implementation of the embodiments of the present application, the aspects of the embodiments of the present application may be combined with various alternatives in one or more of the embodiments described above.

In the embodiment of the present application, the stability constraint module 110 includes:

the control layer constraint data determining unit is used for determining at least one of running path deviation constraint data, yaw rate deviation constraint data and centroid side deviation constraint data;

and the execution layer constraint data determining unit is used for determining the rear wheel steering angle limit constraint and/or the rear wheel steering angle change rate constraint.

The constraint data can be adjusted in real time according to environmental information, and the relaxation or tightening constraint is properly performed. For example, if the road surface adhesion coefficient is low, which indicates that the possibility of the vehicle slipping or drifting increases, the constraint-related data is appropriately tightened, such as further limiting the rate of change of the rear wheel steering angle.

In the embodiment of the present application, the rear wheel steering angle determining module 140 includes:

the first turning angle data determining unit is used for superposing the rear wheel steering feedback control data and the rear wheel steering feedforward control data to determine first turning angle data of the rear wheels;

and the weighting calculation unit is used for performing weighted summation on the first rotation angle data and the second rotation angle data to determine target rotation angle data.

The superposition is an addition operation. In the weighted summation operation process, the weight multiplied by the first rotation angle data can be set according to historical experience or actual requirements, and the weight multiplied by the second rotation angle data can also be set according to historical experience or actual requirements.

In this embodiment, the execution control module 150 includes:

an actual turning angle determination unit for determining actual turning angle data of the rear wheels of the vehicle;

and the difference value calculating unit is used for calculating the difference value between the actual corner data and the target corner data and controlling the steering operation of the rear wheels of the vehicle according to the difference value.

The actual corner data comprises an actual rear wheel steering angle, and the target corner data comprises a preset ideal rear wheel steering angle. The difference value calculating unit controls the steering of the rear wheels of the vehicle to enable the actual corner data to be close to the target corner data continuously.

In an embodiment of the present application, the actual rotation angle determining unit includes:

a rear wheel steering motor position sensor for determining first rack position data;

a rear wheel steering assembly alignment line position sensor for determining second rack position data;

and the actual corner calculating subunit is used for determining actual position data of the rack according to the first rack position data and the second rack position data, and determining actual corner data according to the linear-angular ratio parameter and the actual position data of the rack.

The actual rotation angle determining unit determines the rack position through the rear wheel steering motor position sensor and the rear wheel steering assembly arrangement line position sensor respectively to obtain first rack position data and second rack position data respectively. If the first rack position data and the second rack position data are the same, taking the first rack position data or the second rack position data as rack actual position data; if the first rack position data and the second rack position data are different, the first rack position data and the second rack position data may be re-determined, or a position data between the first rack position data and the second rack position data, for example, a position data of a midpoint of a connecting line of the first rack position data and the second rack position data, may be used as the actual rack position data. And then converting the actual position data of the rack into actual corner data through the linear-angular ratio parameter.

The two rack positions are obtained through signal calculation acquired by the two different sensors, and the more accurate actual positions of the racks can be obtained through a mode of mutually verifying the two rack positions.

In an embodiment of the present application, the stability constraint module includes: the control layer constraint data determining unit is used for determining at least one of running path deviation constraint data, yaw rate deviation constraint data and centroid side deviation constraint data; and the execution layer constraint data determining unit is used for determining the rear wheel steering angle limit constraint and/or the rear wheel steering angle change rate constraint. By determining the constraint data, the data such as yaw velocity and the like can not generate overlarge deviation when the vehicle meets an emergency, and the stability of the vehicle is ensured. The rear wheel steering angle determination module includes: the first turning angle data determining unit is used for superposing the rear wheel steering feedback control data and the rear wheel steering feedforward control data to determine first turning angle data of the rear wheels; and the weighting calculation unit is used for performing weighted summation on the first rotation angle data and the second rotation angle data to determine target rotation angle data. The first corner data determined in the above mode are obtained based on a model, the second corner data are obtained through subjective calibration of an experienced driver, and the data obtained based on the two modes are incorporated into the calculation of the target corner data, so that the setting of the target corner data is more reasonable. The execution control module includes: an actual turning angle determination unit for determining actual turning angle data of the rear wheels of the vehicle; and the difference value calculating unit is used for calculating the difference value between the actual corner data and the target corner data and controlling the steering operation of the rear wheels of the vehicle according to the difference value. Through the scheme, the rear wheel steering can be controlled more accurately, and the stability of the vehicle is ensured. The actual rotation angle determining unit includes: a rear wheel steering motor position sensor for determining first rack position data; a rear wheel steering assembly alignment line position sensor for determining second rack position data; and the actual corner calculating subunit is used for determining actual position data of the rack according to the first rack position data and the second rack position data, and determining actual corner data according to the linear-angular ratio parameter and the actual position data of the rack. The two rack positions are obtained through signal calculation acquired by the two different sensors, and the more accurate actual positions of the racks can be obtained through a mode of mutually verifying the two rack positions.

In an implementation of the embodiments of the present application, the aspects of the embodiments of the present application may be combined with various alternatives in one or more of the embodiments described above.

Fig. 2 is a block diagram of another vehicle stability control system provided in the embodiment of the present application.

In an embodiment of the present application, the system further includes:

an environment information input module 210, configured to acquire environment information and input the environment information to the vehicle stability control system, where the environment information includes at least one of map information, weather information, terrain information, and trajectory information;

the environment information decision module 220 is configured to receive the environment information input by the environment information input module 210, and determine predicted environment information within a target time period according to the environment information.

The environment information can be acquired from the vehicle-mounted terminal or the cloud server, and the acquisition mode of the environment information is not limited in the embodiment of the application. In the embodiment of the application, a prediction model can be built according to algorithms such as machine learning or deep learning, acquired environment information is firstly divided into a training set and a testing set to train the model, and the trained model can predict the environment information in a future target time period according to historical environment information.

According to the embodiment of the application, the predicted environment information in the target time period is determined, so that the deviation of the relevant data of the vehicle can be restrained in advance, the vehicle can adapt to the environment condition of future driving in advance, and the stability of the vehicle is improved.

In an embodiment of the present application, the system further includes:

a driving information input module 230 for acquiring driving information of a vehicle and inputting the driving information to the feedforward control module 130.

In the embodiment of the present application, the running information of the vehicle may be a steering wheel angle, an accelerator pedal opening, a brake pedal opening, and the like. When the vehicle is in manual driving, the driving information input module 230 may acquire vehicle driving information such as a current steering wheel angle, an accelerator pedal opening degree, and a brake pedal opening degree from a sensor in a steering wheel, a sensor in a pedal, and the like. When the vehicle is in automatic driving, the set vehicle running information can be obtained from the upper track planning system.

In the embodiment of the present application, the system further includes:

and a second corner data determining module 240, configured to determine a corner proportion curve according to a two-dimensional interpolation table of a vehicle speed and a steering wheel corner, and determine second corner data according to the driving information and the corner proportion curve.

Wherein the two-dimensional interpolation table is calibrated by an experienced driver. The second steering angle data may be obtained by calculating the travel information and the steering angle proportional curve according to an algorithm, and may be, for example, a product of the steering wheel angle and the steering angle proportional curve.

In an embodiment of the present application, the system further includes:

a state feedback module 250 for collecting driving information of the vehicle after responding to the control performed by the control module 150 and feeding back the driving information to the feedforward control module 130 and the feedback control module 120.

The driving information may be, among others, a vehicle speed, a yaw rate, a steering wheel angle, a centroid slip angle, and the like.

In the embodiment of the application, the vehicle running information is fed back to the feedforward control module 130 and the feedback control module 120 through the state feedback module 250, so that the control layer constraint data and the execution layer constraint data are optimized at any time, and the stability of the vehicle is improved.

It should be noted that the solution in fig. 3 may include the environmental information input module 210, the environmental information decision module 220, the driving information input module 230, the second turning angle data determination module 240, and the state feedback module 250 at the same time, or may not include the above modules, or may include one or a combination of several of the above modules, and may implement the solution of the embodiment of the present application.

In an embodiment of the present application, the vehicle stability control system further includes: the vehicle stability control system comprises an environment information input module, a vehicle stability control module and a vehicle stability control module, wherein the environment information input module is used for acquiring environment information and inputting the environment information to the vehicle stability control system, and the environment information comprises at least one of map information, weather information, terrain information and track information; and the environment information decision module is used for receiving the environment information input by the environment information input module and determining the predicted environment information in the target time period according to the environment information. By determining the predicted environment information in the target time period, the deviation of the relevant data of the vehicle can be restrained in advance, so that the vehicle can adapt to the environment condition of future driving in advance, and the stability of the vehicle is improved. The system further comprises: and the driving information input module is used for acquiring the driving information of the vehicle and inputting the driving information to the feedforward control module so as to control the steering and the turning angle of the rear wheel according to the driving information. The system further comprises: and the second corner data determining module is used for determining a corner proportion curve according to the vehicle speed and a two-dimensional interpolation table of the steering wheel corner, and determining second corner data according to the driving information and the corner proportion curve. The second corner data is obtained by a two-dimensional interpolation table which is subjectively calibrated by an experienced driver, and the data with the subjective calibration characteristic is incorporated into the calculation of the target corner data, so that the target corner data can be set more reasonably. The system further comprises: and the state feedback module is used for acquiring running information of the vehicle after responding to the control of the execution control module and feeding the running information back to the feedforward control module and the feedback control module. The vehicle running information is fed back to the feedforward control module and the feedback control module through the state feedback module, so that control layer constraint data and execution layer constraint data are optimized at any time, and the stability of the vehicle is improved.

Fig. 3 is a flowchart of a vehicle stability control method provided in an embodiment of the present application, which is executed by a vehicle stability control system provided in an embodiment of the present application. The technical scheme of the embodiment of the application can be suitable for the scenes of automobile turning or line changing. As shown in fig. 3, a vehicle stability control method provided in an embodiment of the present application includes:

s310, the stability constraint module determines control layer constraint data and execution layer constraint data of rear wheels of the vehicle according to the predicted environment information in the target time period;

s320, the feedback control module determines rear wheel steering feedback control data according to the control layer constraint data and/or the execution layer constraint data;

s330, determining rear wheel forward feed control data by the feed forward control module according to the running information of the vehicle;

s340, determining first corner data of rear wheels according to the rear wheel steering feedback control data and the rear wheel steering feedforward control data and determining target corner data according to second corner data determined by the driving information of the vehicle by a rear wheel corner determining module;

and S350, controlling the steering operation of the rear wheels of the vehicle by the execution control module based on the target steering angle data.

Fig. 4 is a block diagram of a structure of another vehicle stability control system provided in an embodiment of the present application. As shown in fig. 4, the system includes:

the information input module 1 (corresponding to an environment information input module) is characterized in that input information is not limited to map information, weather information, terrain information, track information, and the like. The cloud end is used for extracting the point cloud data of the front road surface, does not depend on structures such as an acceleration sensor and an active suspension attached to a vehicle, and is not limited by the influence of objective factors such as light, night and weather.

Specifically, the map information includes, but is not limited to, road conditions, accident labels, traffic, and the like. Weather information includes, but is not limited to, weather, temperature, humidity, wind, etc. Topographical information includes, but is not limited to, snow, ice, grass, gravel, sand, etc.

The road surface characteristic decision module 2 (equivalent to an environmental information decision module) is characterized in that: and predicting the information characteristics of the running road surface of the vehicle in the future time period based on the map information, the topographic information, the meteorological information and the like of the current road section, so that the rear wheel steering vehicle control system can adjust the stability boundary in advance to adapt to the change of the future road surface condition.

For example, low temperatures can cause the rubber to harden, thereby reducing its friction, which manifests itself as skidding or braking inflexibility in tire use; and for example, when an automobile runs at a high speed, the flow field around the automobile body is changed under the action of side wind, the symmetry of the flow field is damaged, the aerodynamic force and the moment of the automobile are changed, the operation stability and the safety of the automobile are influenced, and the automobile is easy to have dangerous behaviors such as yaw, side turning, deviation and the like. By predicting the information characteristics of the running road surface of the vehicle in the future time period, the rear wheel steering vehicle control system can adjust the stability boundary in advance, so that the possibility of dangerous behaviors is reduced.

Stability constraint module 3, characterized by: including control layer constraints and execution layer constraints. Controlling layer constraints includes: a travel path deviation constraint, a yaw rate deviation constraint, a centroid slip angle deviation constraint, and the like. The executive layer constraints include rear wheel steering angle limit constraints, rear wheel steering angle rate of change constraints, and the like. The constraints can be adjusted in real time according to the road surface characteristics, and the vehicle can be properly softened, loosened or tightened. For example, a low road adhesion coefficient indicates an increased possibility of vehicle sideslip or drift, and the restraint may be tightened appropriately, such as to further limit the rear wheel steering stroke or the rear wheel steering rate of change.

The driver input module 4 (corresponding to a travel information input module) is characterized in that: the method comprises two aspects of manual driving and automatic driving, and when the vehicle is in manual driving, the information input by the driver input module comprises a steering wheel angle, an accelerator pedal opening degree, a brake pedal opening degree and the like. The driver input module takes in upper track planning information when the vehicle is in autonomous driving.

Proportional curve 5 (corresponding to the second rotation angle data determination module), characterized in that: the front and rear wheel steering angle proportion curve is obtained through a two-dimensional interpolation table of the vehicle speed and the steering wheel steering angle, and the two-dimensional interpolation table is obtained through subjective calibration of experienced drivers. And multiplying the steering wheel angle by a proportional curve to serve as a rear wheel steering angle target based on subjective calibration.

Feedforward control 6 (equivalent to a feedforward control module) characterized by: and calculating to obtain the rear wheel steering gain under the steady state based on the two-degree-of-freedom vehicle model by taking the constant zero mass center slip angle as a control target. And multiplying the steering wheel angle by the rear wheel steering gain to obtain the feedforward control quantity of the rear wheel steering angle. At low vehicle speeds, the rear wheel steering gain is negative, and in this case, the oversteer is added moderately by the reverse operation of the rear wheels and the front wheels. At high vehicle speeds, the rear wheel steering gain is positive, and a turn in the same direction as the front wheel is made by the rear wheel to compensate for the tendency to oversteer.

Feedback control 7 ((corresponding to a feedback control module)) is characterized in that: and (3) taking the deviation of the driving path, the deviation of the yaw rate, the deviation of the centroid slip angle or one of the deviation of the centroid slip angle as an optimization target, satisfying stability constraint and calculating to obtain the rear wheel steering feedback control quantity.

Rear wheel steering angle is synthesized 8 (is equivalent to rear wheel steering angle and is confirmed the module), characterized in that: and superposing the feedforward control quantity and the feedback control quantity to be used as a rear wheel steering angle target based on the model.

The weight evaluation 9 (corresponding to the weight calculation means) is characterized in that: and carrying out weighted summation on the rear wheel steering angle target based on the subjective calibration and the rear wheel steering angle target based on the model.

Actuator position control 10 (corresponding to an actual rotational angle determining unit) is characterized in that: and calculating to obtain a rack position signal 1 through a rear wheel steering motor position sensor. And a linear position sensor is arranged through the rear wheel steering assembly, and a rack position signal 2 is acquired. The rack position signal 1 and the rack position signal 2 are mutually redundant and mutually checked, the actual position of the rack of the rear wheel steering assembly is comprehensively output, the actual rear wheel steering angle is obtained through conversion through a linear-angle ratio parameter, and the difference value between the target steering angle and the actual steering angle is calculated and used for position closed-loop PID control.

The rear-wheel-steered vehicle 11 is broadly referred to as a fuel-powered vehicle or a steer-by-wire vehicle having a rear-wheel steering function.

State feedback 12 (equivalent to a state feedback module), characterized by: gather whole car signal, specifically include: the speed, the yaw rate, the steering wheel angle, the mass center slip angle and the like are used for controlling the dynamics of the whole vehicle.

The embodiment of the application realizes the control of the steering of the rear wheels of the vehicle through a vehicle stability control method: the method comprises the following steps that a stability constraint module determines control layer constraint data and execution layer constraint data of rear wheels of a vehicle according to predicted environment information in a target time period; the feedback control module determines rear wheel steering feedback control data according to the control layer constraint data and/or the execution layer constraint data; the feed-forward control module determines the feed-forward control data of the rear wheel according to the driving information of the vehicle; the rear wheel steering angle determining module is used for determining first steering angle data of the rear wheels according to the rear wheel steering feedback control data and the rear wheel steering feedforward control data, and determining target steering angle data according to second steering angle data determined by the running information of the vehicle; the execution control module controls steering operation of rear wheels of the vehicle based on the target steering angle data. According to the vehicle stability control method provided by the embodiment of the application, the stability boundary is adjusted in advance by predicting the vehicle running environment information in the future time period, so that the vehicle can adapt to the change of the road surface condition in the future as soon as possible. Meanwhile, the vehicle stability control system ensures that data such as yaw velocity and the like do not generate overlarge deviation when the vehicle meets an emergency situation by setting control layer constraint data and execution layer constraint data, and ensures the stability of the vehicle.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present application and the technical principles employed. It will be understood by those skilled in the art that the present application is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the application. Therefore, although the present application has been described in more detail with reference to the above embodiments, the present application is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present application, and the scope of the present application is determined by the scope of the appended claims.