CN106515716A - Coordinated control device and method for chassis integrated control system of wheel-driven electric vehicle - Google Patents

Abstract

The present invention proposes a coordinated control device and method for a chassis integrated control system of a wheel-driven electric vehicle, which belongs to the field of electric vehicles. , vehicle speed sensor, left front wheel speed sensor, right front wheel speed sensor, left rear wheel speed sensor, right rear wheel speed sensor, coordination control unit, AFS controller, ABS controller and DYC controller, the present invention Analyze the different working conditions of the vehicle, judge the suitable control conditions of each subsystem, design a coordinated control system, make each subsystem reasonably allocate their respective responsibilities, give full play to their respective advantages, improve the stability of the vehicle, and solve various problems in the chassis integration system. The problem of mutual coupling between subsystems can maximize the function of each subsystem.

Description

Coordinated control device and method for chassis integrated control system of wheel-driven electric vehicle

technical field

The invention belongs to the field of electric vehicles, and in particular relates to a coordinated control device and method for a chassis integrated control system of a wheel-driven electric vehicle.

Background technique

The four-wheel independent drive characteristics of wheel-drive electric vehicles make it difficult for traditional chassis control technology to adapt. At the same time, the four drive wheels work together with the steering system, and each can be adjusted independently, which also provides more space for the improvement of vehicle control performance.

Active Front Steering (AFS) has been relatively mature in traditional fuel vehicles. The system provides a lateral compensation force for the vehicle by adjusting the steering of the vehicle, corrects the side slip angle of the vehicle's center of mass, and improves the vehicle's handling performance; but For wheel-drive electric vehicles, due to the independent control of the torque of the two front wheels, the relationship between the vehicle steering system and the four-wheel traction system is more direct, and it is difficult to obtain comparable handling performance with traditional vehicles only by controlling the steering system; The additional yaw moment that can be generated at the front wheel angle is a good description of the functional scope of the independent control of the AFS subsystem. The ability of AFS to control oversteer is greater than that of understeer; the front wheel angle increases to At a certain value, the increase of the front wheel compensation angle cannot produce a larger yaw moment increment, indicating that the tire has reached a saturated state at this time, and the change of the small front wheel rotation angle has almost no effect on the lateral force. To sum up, AFS can effectively correct the yaw motion of the vehicle in the small range of front wheel rotation angle (in the linear region), and the correction effect for oversteering is better than that for understeering; but the front wheel When the steering angle is too large (in the non-linear region), the correction ability of AFS is very limited.

Direct Yaw Moment Control (DYC) regulates the vehicle's four-wheel traction to prevent tail flicking. DYC can generate a large enough yaw moment increment, and is less limited and affected by the steering of the front wheels, indicating that it has a good correction ability for oversteering and understeering, and dynamically adjusts the yaw movement of the vehicle , to improve vehicle stability, and the control effect is very good under extreme working conditions, but because it controls the longitudinal force of the vehicle, it will inevitably have a greater impact on the longitudinal motion of the vehicle, resulting in reduced vehicle speed and affecting ride comfort and other issues.

Anti-lock brake control (ABS) controls the braking force of the vehicle according to the tire slip rate, improves the braking safety of the vehicle, and shortens the braking distance of the vehicle.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention proposes a coordinated control device and method for a chassis integrated control system of a wheel-driven electric vehicle, which improves the handling stability of the vehicle and solves the problem of mutual coupling between subsystems in the chassis integrated system, maximizing Exert the functions of each subsystem.

A coordinated control device for a chassis integrated control system of a wheel-driven electric vehicle, the device includes: a driver's control platform, an ideal value generation unit for attitude parameters, a vehicle lateral deviation observation unit, a yaw rate sensor, a vehicle speed sensor, and a left front wheel speed sensor. sensor, right front wheel speed sensor, left rear wheel speed sensor, right rear wheel speed sensor, coordination control unit, AFS controller, ABS controller and DYC controller, among which,

Driver manipulation platform: used to convert driver manipulation instructions into vehicle target speed signal and target angle signal, and simultaneously send the target angle signal to the attitude parameter ideal value generation unit and the coordination control unit, and send the target speed signal to the attitude parameter ideal value generating unit;

Attitude parameter ideal value generation unit: used to obtain the target value of yaw rate, center of mass side slip angle and vehicle slip rate target value according to the target speed signal, target corner signal and road surface adhesion coefficient, and send them to the coordination control unit ;

Vehicle side slip observation unit: used to observe the side slip angle of the center of mass in real time and send it to the coordination control unit;

Yaw rate sensor: used to collect and detect vehicle yaw rate and send it to the coordination control unit;

Vehicle speed sensor: used to collect vehicle speed and send it to the coordination control unit;

Left front wheel speed sensor: used to collect the left front wheel speed of the vehicle and send it to the coordination control unit;

Right front wheel speed sensor: used to collect the speed of the right front wheel of the vehicle and send it to the coordination control unit;

Left rear wheel speed sensor: used to collect the left rear wheel speed of the vehicle and send it to the coordination control unit;

Right rear wheel speed sensor: used to collect the right rear wheel speed of the vehicle and send it to the coordination control unit;

Coordination control unit: used to obtain the front wheel cornering force and the state control signals of the AFS controller, ABS controller and DYC controller according to the collected vehicle speed and target angle signals; and according to the front wheel cornering force and the observed center of mass of the vehicle According to the side slip angle, the fuzzy control output weights of AFS controller, ABS controller and DYC controller are obtained; then according to the state control signals and fuzzy control output weights of AFS controller, ABS controller and DYC controller, the AFS controller’s The control weight value, the control weight value of the ABS controller, and the control weight value of the DYC controller are sent to the AFS controller, the ABS controller, and the DYC controller respectively; finally, according to the collected vehicle speed, vehicle yaw rate, and vehicle center of mass Declination angle, vehicle left front wheel speed, vehicle right front wheel speed, vehicle left rear wheel speed, vehicle right rear wheel speed, target value of yaw rate, target value of side slip angle of center of mass and slip angle of the four wheels of the vehicle shift rate target value, obtain the yaw rate deviation, the center of mass sideslip angle deviation and the slip rate deviation of the four wheels, and send the yaw rate deviation and the center of mass sideslip angle deviation to the AFS controller, and the four wheels The slip rate deviation is sent to the ABS controller, and the yaw rate deviation is sent to the DYC controller;

AFS controller: used to obtain the front wheel compensation angle of the vehicle according to the received attitude parameters, the center of mass side slip angle deviation, the yaw rate deviation and the corresponding control weight value, and send it to the vehicle's steering angle motor;

ABS controller: used to obtain the tire braking force of the left front wheel, right front wheel, left rear wheel, and right rear wheel of the vehicle according to the received slip ratio deviation of the four wheels of the vehicle and the corresponding control weight value, and send them to the In the left front wheel brake device, right front wheel brake device, left rear wheel brake device, right rear wheel brake device;

DYC controller: used to obtain the four wheel motor torque target values according to the received yaw rate deviation and the corresponding control weight value, and send them to the left front wheel hub motor and its control system of the vehicle, and the right front wheel hub respectively Motor and its control system, left rear wheel hub motor and its control system, right rear wheel hub motor and its control system.

The coordination control unit includes: a vehicle state identification unit, a fuzzy coordination controller, a control logic unit and a deviation generation unit; wherein,

Vehicle state identification unit: used to obtain the front wheel cornering force and the state control signals of the AFS controller, ABS controller and DYC controller according to the collected vehicle speed and target angle signals, and send the front wheel cornering force to the fuzzy coordination In the controller, the state control signals of the AFS controller, ABS controller and DYC controller are sent to the control logic unit;

Fuzzy coordination controller: used to obtain the fuzzy control output weights of the AFS controller, ABS controller and DYC controller according to the side cornering force of the front wheels and the observed side slip angle of the vehicle center of mass, and send them to the control logic unit;

Control logic unit: used to obtain the control weight value of the AFS controller, the control weight value of the ABS controller and the control of the DYC controller according to the state control signals and fuzzy control output weights of the AFS controller, ABS controller and DYC controller The weight value is sent to the AFS controller, ABS controller and DYC controller respectively;

Deviation generating unit: used for collecting vehicle speed, vehicle yaw rate, vehicle side slip angle, vehicle left front wheel speed, vehicle right front wheel speed, vehicle left rear wheel speed, vehicle right rear wheel speed, The yaw rate target value, the center of mass sideslip angle target value and the vehicle slip rate target value, obtain the yaw rate deviation, the center of mass side slip angle deviation and the slip rate deviation of the four wheels, and combine the yaw rate deviation and the center of mass The side slip angle deviation is sent to the AFS controller, the slip rate deviation of the four wheels is sent to the ABS controller, and the yaw rate deviation is sent to the DYC controller.

The control method performed by the coordinated control device of the chassis integrated control system of the wheel-driven electric vehicle includes the following steps:

Step 1. The driver's manipulation platform converts the driver's manipulation command into a vehicle target speed signal and a target angle signal, and simultaneously sends the target angle signal to the attitude parameter ideal value generation unit and the coordination control unit, and sends the target speed signal to the attitude parameter ideal value generating unit;

Step 2. The attitude parameter ideal value generating unit obtains the target yaw rate value, the target value of the side slip angle of the center of mass and the target value of the slip rate of the vehicle according to the target speed signal, the target corner signal and the road surface adhesion coefficient, and sends them to the coordination control unit ;

Step 3, use the vehicle side deviation observation unit to observe the side slip angle of the center of mass in real time, and send it to the coordination control unit;

Step 4. Use the yaw angular velocity sensor to collect and detect the vehicle yaw angular velocity, use the vehicle speed sensor to collect the vehicle speed, use the left front wheel speed sensor to collect the vehicle left front wheel speed, and use the right front wheel speed sensor to collect the vehicle right front wheel speed , using the left rear wheel speed sensor to collect the left rear wheel speed of the vehicle, using the right rear wheel speed sensor to collect the right rear wheel speed of the vehicle, and sending the above collected parameters to the coordination control unit;

Step 5. The vehicle state identification unit inside the coordination control unit obtains the front wheel cornering force and the state control signals of the AFS controller, ABS controller and DYC controller according to the collected vehicle speed and target angle signals, and calculates the front wheel cornering force The force is sent to the fuzzy coordination controller inside the coordination control unit, and the state control signals of the AFS controller, ABS controller and DYC controller are sent to the control logic unit inside the coordination control unit;

Step 6. The fuzzy coordination controller obtains the fuzzy control output weights of the AFS controller, the ABS controller and the DYC controller according to the side cornering force of the front wheels and the observed side slip angle of the vehicle center of mass, and sends them to the control logic unit;

Step 7, the control logic unit obtains the control weight value of the AFS controller, the control weight value of the ABS controller and the control of the DYC controller according to the state control signal and the fuzzy control output weight of the AFS controller, ABS controller and DYC controller The weight value is sent to the AFS controller, ABS controller and DYC controller respectively;

Step 8. The deviation generating unit inside the coordination control unit is based on the collected vehicle speed, vehicle yaw rate, vehicle side slip angle, vehicle left front wheel speed, vehicle right front wheel speed, vehicle left rear wheel speed, vehicle right Rear wheel speed, yaw rate target value, center-of-mass sideslip angle target value and vehicle slip rate target value, obtain the yaw rate deviation, center-of-mass side slip angle deviation and slip rate deviation of the four wheels, and calculate the lateral Sway rate deviation and center of mass side slip angle deviation are sent to the AFS controller, slip rate deviations of the four wheels are sent to the ABS controller, and yaw rate deviations are sent to the DYC controller;

Step 9. The AFS controller obtains the vehicle front wheel compensation angle according to the received yaw rate deviation, the center of mass side slip angle deviation and the corresponding control weight value, and sends it to the vehicle's steering angle motor;

Step 10. The ABS controller obtains the tire braking forces of the left front wheel, right front wheel, left rear wheel, and right rear wheel of the vehicle according to the received slip ratio deviations of the four wheels and the corresponding control weight values, and sends them to the vehicle respectively In the left front wheel brake device, right front wheel brake device, left rear wheel brake device, right rear wheel brake device;

Step 11. The DYC controller obtains the torque target values of the four wheel motors according to the received yaw rate deviation and the corresponding control weight values, and sends them to the left front wheel hub motor and its control system of the vehicle, and the right front wheel hub motor respectively. Motor and its control system, left rear wheel hub motor and its control system, right rear wheel hub motor and its control system.

The attitude parameter ideal value generation unit described in step 2 obtains the target yaw rate value and the target value of the slip ratio of the four wheels of the vehicle according to the target speed signal, the target corner signal and the road surface adhesion coefficient, and sends them to the coordination control unit;

When the vehicle turns left, that is, δ _d > 0, the specific formula of the target value of the yaw rate is as follows:

When the vehicle turns right, that is, δ _d <0, the specific formula of the target value of the yaw rate is as follows:

Among them, K represents the stability factor, γ ^* represents the target value of yaw rate, v _d represents the target speed signal, δ _d represents the target rotation angle signal, μ represents the road surface adhesion coefficient, g represents the gravitational acceleration, l=l _r + l _f , l _r represents the distance from the center of mass to the front axle, l _f represents the distance from the center of mass to the rear axle, β ^* represents the target value of the side slip angle of the center of mass, C _f represents the stiffness coefficient of the front wheel tire, and C _r represents the stiffness coefficient of the rear wheel tire ; m represents the mass of the vehicle;

The target value of the slip ratio of the four wheels of the vehicle: obtained according to the relationship between the slip ratio of the four wheels of the vehicle and the road surface adhesion coefficient.

The vehicle state identification unit inside the coordination control unit described in step 5 obtains the front wheel cornering force and the state control signals of the AFS controller, ABS controller and DYC controller according to the collected vehicle speed and target angle signals, and sends the front wheel The cornering force is sent to the fuzzy coordination controller inside the coordination control unit, and the state control signals of the AFS controller, ABS controller and DYC controller are sent to the control logic unit inside the coordination control unit;

Get front wheel cornering force The specific calculation is as follows:

Construct the kinetic differential equation:

Among them, m represents the mass of the vehicle, v _x represents the longitudinal velocity of the vehicle, β represents the side slip angle of the observed center of mass, γ represents the yaw rate, F _yfl represents the lateral force of the left front wheel, and F _yfr represents the lateral force of the right front wheel , F _yrl represents the lateral force of the left rear wheel, F _yrr represents the lateral force of the right rear wheel, J represents the moment of inertia of the wheel motor, l _r represents the distance from the center of mass to the front axle, l _f represents the distance from the center of mass to the rear axle, M Indicates the external yaw moment;

Simplify formulas (3) and (4), let F _yf =F _yfl +F _yfr , F _yr =F _yrl +F _yrr , get:

ma _y =F _yf +F _yr (5)

Among them, a _y represents the lateral acceleration of the vehicle, F _yf represents the lateral force of the front tire of the monorail model, and F _yr represents the lateral force of the rear tire of the monorail model;

Estimate F _yf in formula (5) and formula (6), and obtain the following formula:

in, is the estimator of F _yf ;

Among them, m _f =ml _r /l, l=l _r +l _f ;

Obtain the state control signals of the AFS controller, ABS controller and DYC controller, as follows:

According to the front wheel angle, the longitudinal deceleration of the vehicle and the steering characteristics of the vehicle, the driving state of the vehicle can be judged, as shown in Table 1:

Table 1 Vehicle driving state identification logic

In Table 1, δ represents the front wheel rotation angle, δ _thres represents the threshold value of the front wheel rotation angle, a _x represents the longitudinal acceleration of the vehicle, a _xthres represents the threshold value of the longitudinal acceleration, and v _ch represents the characteristic vehicle speed;

According to the vehicle driving state in Table 1, the state control signal η of the AFS controller, ABS controller and DYC controller is obtained, as shown in Table 2:

Table 2 State control signal table of AFS controller, ABS controller and DYC controller

Output the state control signal η of the AFS controller, ABS controller and DYC controller: the eight states are expressed in binary as 000, 001, 010, 011, 100, 101, 110, and 111 are converted into decimals, respectively 0 to 7, as shown in the table In 2, 1 indicates that the controller is working, and 0 indicates that the controller is not working. The value of the status signal is determined by converting the binary code of the working status of each subsystem into decimal under different working conditions.

The fuzzy coordination controller described in step 6 obtains the fuzzy control output weights of the AFS controller, ABS controller and DYC controller according to the front wheel cornering force and the observed center of mass sideslip angle, and sends them to the control logic unit;

details as follows:

sideways force on the front wheel The historical data of the historical data and the historical data of the center of mass sideslip angle β are used as the input of the fuzzy controller, and the fuzzy control output weight ω is used as the output of the fuzzy controller. Based on the discourse domain of center of mass sideslip angle β and fuzzy control output weight ω, the fuzzy control rule is obtained, and according to the front wheel lateral force in the fuzzy control rule and the center of mass sideslip angle β to obtain the corresponding fuzzy control output weight ω.

The control logic unit described in step 7 obtains the control weight value of the AFS controller, the control weight value of the ABS controller and the DYC controller according to the state control signal and the fuzzy control output weight of the AFS controller, ABS controller and DYC controller The control weight values are sent to the AFS controller, ABS controller and DYC controller respectively;

According to the eight states output by the vehicle identification unit and the fuzzy control output weight, the control weight value η _AFS of the AFS controller, the control weight value η _ABS of the ABS controller and the control weight value η _DYC of the DYC controller are obtained, as shown in Table 3. ,Table 4:

Table 3 Control weight table of AFS controller and DYC controller

Table 4 ABS controller control weight table

Among them, ω represents the output weight of fuzzy control.

The deviation generating unit inside the coordination control unit described in step 8 is based on the collected vehicle speed, vehicle yaw rate, vehicle side slip angle, vehicle left front wheel speed, vehicle right front wheel speed, vehicle left rear wheel speed, The wheel speed of the right rear wheel of the vehicle, the target value of the yaw rate, the target value of the side slip angle of the center of mass and the target value of the slip rate of the four wheels of the vehicle, and obtain the deviation of the yaw rate, the deviation of the side slip angle of the center of mass and the slip rate of the four wheels deviation, and send the yaw rate deviation and the center of mass side slip angle deviation to the AFS controller, send the slip rate deviation of the four wheels to the ABS controller, and send the yaw rate deviation to the DYC controller;

The specific formula is as follows:

S _ij =(w _ij Rv)/v (11)

Among them, Δγ represents the deviation of yaw rate, γ* represents the target value of yaw rate, γ represents the yaw rate obtained by the yaw rate sensor, ΔS _ij represents the slip rate deviation of the four wheels, and i is f or r, j is r or l, s ^* indicates the target slip ratio of the four wheels of the vehicle, S _ij indicates the road tracking slip rate of the four wheels, Δβ indicates the deviation of the center of mass sideslip angle, β ^* indicates the target value of the center of mass sideslip angle, β Represents the side slip angle of the center of mass obtained by the vehicle lateral deviation observation unit, w _ij represents the wheel speed of the four wheels, R represents the tire radius, and v represents the vehicle speed.

Advantages of the present invention:

The present invention proposes a coordinated control device and method for the chassis integrated control system of a wheel-driven electric vehicle. The present invention analyzes the different working conditions of the vehicle, and judges the various subsystems (AFS controller, ABS controller and DYC controller) Appropriate control conditions, design a coordinated control system, so that each subsystem can reasonably allocate their respective responsibilities, give full play to their respective advantages, and improve vehicle stability; both AFS controller and DYC controller can improve the handling stability of the vehicle, and the integrated advantages of the two It is mainly reflected in that when the steering angle of the front wheels increases to a certain value, the DYC controller has a good correction effect on oversteer and understeer, but the correction ability of the AFS controller is limited; the two are integrated to form a chassis integration The control system, the two are complementary, can make the vehicle achieve higher performance; the control of the DYC controller is to generate the required longitudinal force through the ABS controller, so it will have different effects on the control of the ABS controller and the braking effect of the vehicle. Definite impact; similarly, the braking of the vehicle will also limit the control of the DYC controller; therefore, integrated control is also required between the DYC controller and the ABS controller;

The chassis integrated control system comprising AFS controller, DYC controller and ABS controller of the present invention can realize the control of the longitudinal, lateral and yaw motion of the vehicle, and improve the handling stability; Therefore, the present invention adopts a coordinated control method to logically organize several systems together to maximize their respective advantages and solve the problem of mutual coupling.

Description of drawings

Fig. 1 is a structural block diagram of a coordinated control device of a wheel-driven electric vehicle chassis integrated control system according to an embodiment of the present invention;

Fig. 2 is a block diagram of the internal structure of the coordination control unit of an embodiment of the present invention;

Fig. 3 is a flow chart of a coordinated control method for a chassis integrated control system of a wheel-driven electric vehicle according to an embodiment of the present invention;

Fig. 4 is a schematic diagram of the membership function of the front wheel lateral force in an embodiment of the present invention;

Fig. 5 is a schematic diagram of the membership function of the slip angle according to an embodiment of the present invention;

6 is a schematic diagram of a membership function of a weight ω in an embodiment of the present invention;

Fig. 7 is a given schematic diagram of vehicle speed and front wheel angle in an embodiment of the present invention, wherein, figure (a) is a given schematic diagram of front wheel angle, and figure (b) is a given schematic diagram of vehicle speed;

Fig. 8 is a schematic diagram of a vehicle yaw rate comparison curve according to an embodiment of the present invention;

Fig. 9 is a schematic diagram of the slip ratio of each wheel of the vehicle according to an embodiment of the present invention;

Fig. 10 is a schematic diagram of a vehicle state signal according to an embodiment of the present invention;

Fig. 11 is a schematic diagram of the control weights of each subsystem in an embodiment of the present invention.

detailed description

An embodiment of the present invention will be further described below in conjunction with the accompanying drawings.

In the embodiment of the present invention, as shown in FIG. 1 , the coordinated control device of the chassis integrated control system of a wheel-driven electric vehicle includes: a driver's control platform, an ideal value generating unit for attitude parameters, a vehicle lateral deviation observation unit, a yaw rate sensor, Vehicle speed sensor, left front wheel speed sensor, right front wheel speed sensor, left rear wheel speed sensor, right rear wheel speed sensor, coordination control unit, AFS controller, ABS controller and DYC controller;

In the embodiment of the present invention, the vehicle speed sensor, the left front wheel speed sensor, the right front wheel speed sensor, the left rear wheel speed sensor, and the right rear wheel speed sensor all adopt the CM18-65D-3-24V model vehicle speed and wheel speed sensor. sensor.

In the embodiment of the present invention, the driver's manipulation platform: used to convert the driver's manipulation instruction into a target speed signal and a target angle signal of the vehicle, simultaneously send the target angle signal to the attitude parameter ideal value generation unit and the coordination control unit, and convert the target speed signal Send to the attitude parameter ideal value generation unit; the attitude parameter ideal value generation unit: used to obtain the yaw rate target value, the center of mass side slip angle target value and the slip rate of the vehicle according to the target speed signal, the target corner signal and the road surface adhesion coefficient Target value, and sent to the coordination control unit; vehicle side deviation observation unit: used for real-time observation of the side slip angle of the center of mass, and sent to the coordination control unit; yaw rate sensor: used to collect and detect the vehicle yaw rate, and sent to the coordination Control unit; vehicle speed sensor: used to collect vehicle speed and send it to the coordination control unit; left front wheel speed sensor: used to collect the left front wheel speed of the vehicle and send it to the coordination control unit; right front wheel speed sensor: use Used to collect the speed of the right front wheel of the vehicle and send it to the coordination control unit; the left rear wheel speed sensor: used to collect the speed of the left rear wheel of the vehicle and send it to the coordination control unit; the right rear wheel speed sensor: used to collect The wheel speed of the right rear wheel of the vehicle is sent to the coordination control unit;

In the embodiment of the present invention, as shown in Figure 2, the coordination control unit includes: a vehicle state identification unit, a fuzzy coordination controller, a control logic unit, and a deviation generation unit; wherein, the vehicle state identification unit: Vehicle speed and target angle signals, obtain the front wheel cornering force and the state control signals of the AFS controller, ABS controller and DYC controller, and send the front wheel cornering force to the fuzzy coordination controller, and the AFS controller, ABS controller The state control signals of the controller and DYC controller are sent to the control logic unit; fuzzy coordination controller: used to obtain the AFS controller, ABS controller and DYC control according to the front wheel cornering force and the observed side slip angle of the vehicle center of mass The fuzzy control output weight of the controller is sent to the control logic unit; the control logic unit is used to obtain the control weight of the AFS controller according to the state control signal and fuzzy control output weight of the AFS controller, ABS controller and DYC controller value, the control weight value of the ABS controller and the control weight value of the DYC controller, and send them to the AFS controller, the ABS controller and the DYC controller respectively; the deviation generation unit: used to obtain the vehicle speed, vehicle yaw rate , vehicle mass center slip angle, vehicle left front wheel speed, vehicle right front wheel speed, vehicle left rear wheel speed, vehicle right rear wheel speed, yaw rate target value, center of mass side slip angle target value and vehicle four The slip rate target value of each wheel, obtain the yaw rate deviation, the center of mass sideslip angle deviation and the slip rate deviation of the four wheels, and send the yaw rate deviation and the center of mass sideslip angle deviation to the AFS controller, and send it to the AFS controller. The slip rate deviation of the four wheels is sent to the ABS controller, and the yaw rate deviation is sent to the DYC controller.

In the embodiment of the present invention, the AFS controller is used to obtain the front wheel compensation angle of the vehicle according to the received attitude parameters, the sideslip angle deviation of the center of mass, the yaw rate deviation and the corresponding control weight value, and send it to the steering assist angle of the vehicle In the motor; ABS controller: used to obtain the tire braking force of the left front wheel, right front wheel, left rear wheel, and right rear wheel of the vehicle according to the received slip ratio deviation of the four wheels of the vehicle and the corresponding control weight value, and respectively sent to the vehicle's left front wheel braking device, right front wheel braking device, left rear wheel braking device, and right rear wheel braking device; Control the weight value to obtain the torque target values of the four wheel motors, and send them to the left front wheel hub motor and its control system, the right front wheel hub motor and its control system, the left rear wheel hub motor and its control system, In the right rear wheel hub motor and its control system;

In the embodiment of the present invention, the steering angle motor of the vehicle, the left front wheel brake device, the right front wheel brake device, the left rear wheel brake device, the right rear wheel brake device, the left front wheel brake device of the vehicle, The hub motor and its control system, the right front wheel hub motor and its control system, the left rear wheel hub motor and its control system, and the right rear wheel hub motor and its control system are all controlled objects inside the vehicle and belong to the existing technology.

In the embodiment of the present invention, the control method performed by the coordinated control device of the wheel-driven electric vehicle chassis integrated control system is used. The method flow chart is shown in Figure 3, including the following steps:

Step 1. The driver's manipulation platform converts the driver's manipulation instruction into vehicle target speed signal v _d and target rotation angle signal δ _d , and simultaneously sends the target rotation angle signal δ _d to the attitude parameter ideal value generation unit and the coordination control unit, and converts the target speed signal v _d is sent to the attitude parameter ideal value generation unit;

Step 2. The attitude parameter ideal value generation unit obtains the target yaw rate value γ ^* , the target value of the sideslip angle of the center of mass β ^* and the slip rate of the vehicle according to the target speed signal v _d , the target rotation angle signal δ _d and the road surface adhesion coefficient μ Target value s ^* , and sent to the coordination control unit;

In the embodiment of the present invention, according to the steady-state steering principle of the two-degree-of-freedom model, the yaw rate is given assuming that the vehicle is in the positive direction when turning left, that is, δ _d > 0, and the ideal yaw rate is expressed as:

When the vehicle turns right, that is, δ _d <0, the specific formula of the target value of the yaw rate is as follows:

Among them, K represents the stability factor, γ* represents the target value of yaw rate, v _d represents the target speed signal, δ _d represents the target rotation angle signal, μ represents the road surface adhesion coefficient, g represents the gravitational acceleration, l=l _r + l _f , l _r represents the distance from the center of mass to the front axle, l _f represents the distance from the center of mass to the rear axle, β ^* represents the target value of the side slip angle of the center of mass, C _f represents the stiffness coefficient of the front wheel tire, and C _r represents the stiffness coefficient of the rear wheel tire ; m represents the mass of the vehicle;

In the embodiment of the present invention, the slip ratio target value of the four wheels of the vehicle is obtained according to the relationship between the slip ratio of the four wheels of the vehicle and the road surface adhesion coefficient;

Step 3. Observing the side slip angle β of the center of mass in real time by using the vehicle slip observation unit, and sending it to the coordination control unit;

Step 4. Use the yaw angular velocity sensor to collect and detect the vehicle yaw angular velocity γ, use the vehicle speed sensor to collect the vehicle speed v, use the left front wheel speed sensor to collect the left front wheel speed ω _fl of the vehicle, and use the right front wheel speed sensor to collect the vehicle right For the front wheel speed ω _fr , the left rear wheel speed sensor is used to collect the left rear wheel speed ω _rl of the vehicle, and the right rear wheel speed sensor is used to collect the vehicle right rear wheel speed ω _rr , and the above collected parameters are sent to the coordinated control unit;

Step 5. The vehicle state identification unit inside the coordination control unit obtains the front wheel cornering force according to the collected vehicle speed v and the target angle signal δ _d And the state control signal η of AFS controller, ABS controller and DYC controller, and the front wheel cornering force Send to the fuzzy coordination controller inside the coordination control unit, send the state control signal η of the AFS controller, the ABS controller and the DYC controller to the control logic unit inside the coordination control unit;

Get front wheel cornering force The specific calculation is as follows:

Construct the kinetic differential equation:

Among them, m represents the mass of the vehicle, v _x represents the longitudinal velocity of the vehicle, β represents the side slip angle of the observed center of mass, γ represents the yaw rate, F _yfl represents the lateral force of the left front wheel, and F _yfr represents the lateral force of the right front wheel , F _yrl represents the lateral force of the left rear wheel, F _yrr represents the lateral force of the right rear wheel, J represents the moment of inertia of the wheel motor, l _r represents the distance from the center of mass to the front axle, l _f represents the distance from the center of mass to the rear axle, M Indicates the external yaw moment;

Simplify formulas (5) and (6), let F _yf =F _yfl +F _yfr , F _yr =F _yrl +F _yrr , get:

ma _y =F _yf +F _yr (7)

Among them, a _y represents the lateral acceleration of the vehicle, F _yf represents the lateral force of the front tire of the monorail model, and F _yr represents the lateral force of the rear tire of the monorail model;

Estimate F _yf in formula (7) and formula (8), and obtain the following formula:

in, is the estimator of F _yf ;

Among them, m _f =ml _r /l, l=l _r +l _f ;

In the embodiment of the present invention, the dynamic difference between the left and right wheels and the tire force is ignored, and the tire force is simplified as the product of the equivalent cornering stiffness and the wheel slip angle, namely:

Among them, the side slip angle of the tire is as follows:

Then the two-degree-of-freedom vehicle lateral dynamics model can be simplified as:

Expressed in the state equation form as:

in,

According to the state equation (15) of the reference model, its characteristic equation can be obtained by det(sI-A)=0:

s ² +K ₁ s+K ₀ =0 (16)

in:

In the embodiment of the present invention, according to the Hurwitz stability criterion, the constant term and the coefficient of the first-order term must be greater than 0 for system stability, that is, K ₀ >0, K ₁ >0; since all items in K ₁ are positive numbers, it is always established, just consider that K ₀ >0, that is, the molecule is greater than 0, and the stability condition can be obtained as:

in, Defined as characteristic vehicle speed (v _ch ≠0);

This formula will be used as the basis for judging the stability of the system:

vehicle stability

vehicle critical stability

vehicle instability

Usually the characteristic speed is regarded as a constant, but when the driving conditions change during the actual operation of the vehicle, the parameters of the tires will also change, resulting in a change in the characteristic speed; therefore, it is necessary to calculate the characteristic speed according to the vehicle state information. When the vehicle is In steady-state steering, the steady-state yaw rate can be expressed as:

According to the vehicle state information such as vehicle speed, yaw rate, tire rotation angle, etc., the characteristic vehicle speed expression is:

Under steady-state conditions, the yaw rate can be approximately expressed as γ=v _x /ρ, where v _x is the longitudinal velocity of the vehicle, and ρ is the turning radius of the vehicle, which can be brought into equation (19) to get:

On the premise that the steering radius of the vehicle is constant, the front wheel steering angle is defined as δ ₀ when the vehicle speed is very low and the lateral acceleration is approximately zero (characteristic speed v _ch → ∞); The wheel rotation angle is δ, then the steering angle ratio is:

Considering the steering characteristics and stability conditions, the steering characteristics are divided into five cases as follows:

(1) when When , the vehicle is in the region of large oversteer instability;

(2) when When , the vehicle is in the small oversteer conservative stable area;

(3) when When , the vehicle is in neutral steering;

(4) when When , the vehicle is in the small understeer stable area;

(5) when , the vehicle is in the large understeer region, and according to the stability criterion, this working condition is a stable working condition, but in actual situations, the vehicle is prone to track deviation when cornering at high speed, so it is regarded as an extreme dangerous working condition;

In the embodiment of the present invention, in order to more clearly define and clearly identify the specific state in the process of driving the vehicle, based on the threshold value and according to the steering characteristics and stability criteria of the vehicle, the driving state of the vehicle is judged. Table 1 summarizes the driving state of the vehicle The identification logic:

Table 1 Vehicle driving state identification logic

In Table 1, δ represents the front wheel rotation angle, δ _thres represents the threshold value of the front wheel rotation angle, a _x represents the longitudinal acceleration of the vehicle, a _xthres represents the threshold value of the longitudinal acceleration, and v _ch represents the characteristic vehicle speed;

According to the vehicle driving state in Table 1, the state control signal η of the AFS controller, ABS controller and DYC controller is obtained, as shown in Table 2:

Table 2 State control signal table of AFS controller, ABS controller and DYC controller

Output the state control signal η of the AFS controller, ABS controller and DYC controller: the eight states are expressed in binary as 000, 001, 010, 011, 100, 101, 110, and 111 are converted into decimals, respectively 0 to 7, as shown in the table In 2 (the middle three columns), 1 means the controller is working, 0 means the controller is not working, and the value of the status signal is determined by converting the binary code of the working status of each subsystem into decimal under different working conditions;

Step 6. The fuzzy coordination controller obtains the fuzzy control output weights of the AFS controller, ABS controller and DYC controller according to the front wheel cornering force and the observed side slip angle of the vehicle center of mass, and sends them to the control logic unit; the details are as follows :

In the embodiment of the present invention, the fuzzy coordination controller uses the side slip angle β, front wheel cornering force As input, through extensive simulations, it can be obtained that The domain of discourse of β is [0, 10], the domain of discourse of β is [0, 10], and the domain of discourse of ω is [0, 1]; the input variable The fuzzy subset of is: {Fy1, Fy2, Fy3, Fy4, Fy5, Fy6}, the fuzzy subset of the input variable β is: {B1, B2, B3, B4, B5, B6}, the output variable fuzzy control output weight ω The fuzzy subset of is {w1, w2, w3, w4, w5}; input The membership functions of β and output ω are shown in Figures 4 to 6 respectively, and Table 5 is the table of fuzzy control rules;

table 5

Step 7, the control logic unit obtains the control weight value of the AFS controller, the control weight value of the ABS controller and the control of the DYC controller according to the state control signal and the fuzzy control output weight of the AFS controller, ABS controller and DYC controller The weight value is sent to the AFS controller, ABS controller and DYC controller respectively;

According to the eight states output by the vehicle identification unit and the fuzzy control output weight, the control weight value η _AFS of the AFS controller, the control weight value η _ABS of the ABS controller and the control weight value η _DYC of the DYC controller are obtained, as shown in Table 3. ,Table 4:

Table 3 Control weight table of AFS controller and DYC controller

Table 4 ABS controller control weight table

Among them, ω represents the output weight of fuzzy control.

Step 8. The deviation generating unit inside the coordination control unit is based on the collected vehicle speed, vehicle yaw rate, vehicle side slip angle, vehicle left front wheel speed, vehicle right front wheel speed, vehicle left rear wheel speed, vehicle right Rear wheel speed, yaw rate target value, center of mass sideslip angle target value and the slip rate target value of the four wheels of the vehicle to obtain the yaw rate deviation Δγ, the center of mass sideslip angle deviation Δβ and the slip rate of the four wheels The deviation Δs, and the yaw rate deviation Δγ and the center of mass sideslip angle deviation Δβ are sent to the AFS controller, the slip rate deviation Δs of the four wheels is sent to the ABS controller, and the yaw rate deviation Δγ is sent to the DYC in the controller;

The specific formula is as follows:

S _ij =(w _ij Rv)/v (11)

Among them, Δγ represents the deviation of yaw rate, γ* represents the target value of yaw rate, γ represents the yaw rate obtained by the yaw rate sensor, ΔS _ij represents the slip rate deviation of the four wheels, and i is f or r, j is r or l, s ^* indicates the target slip ratio of the four wheels of the vehicle, S _ij indicates the road tracking slip rate of the four wheels, Δγ indicates the center-of-mass sideslip angle deviation, β ^* indicates the target value of the center-of-mass sideslip angle, β Indicates the side slip angle of the center of mass obtained by the vehicle side deviation observation unit, w _ij indicates the wheel speed of the four wheels, R indicates the tire radius, and v indicates the vehicle speed;

Step 9. The AFS controller obtains the vehicle front wheel compensation angle according to the received yaw rate deviation, the center of mass side slip angle deviation and the corresponding control weight value, and sends it to the vehicle's steering angle motor;

Step 10. The ABS controller obtains the tire braking forces of the left front wheel, right front wheel, left rear wheel, and right rear wheel of the vehicle according to the received slip ratio deviations of the four wheels and the corresponding control weight values, and sends them to the vehicle respectively In the left front wheel brake device, right front wheel brake device, left rear wheel brake device, right rear wheel brake device;

Step 11. The DYC controller obtains the torque target values of the four wheel motors according to the received yaw rate deviation and the corresponding control weight values, and sends them to the left front wheel hub motor and its control system of the vehicle, and the right front wheel hub motor respectively. Motor and its control system, left rear wheel hub motor and its control system, right rear wheel hub motor and its control system.

Simulation

Step signal input deceleration driving condition:

In the embodiment of the present invention, in order to verify the effectiveness of the chassis integrated control system designed above, the system is simulated and analyzed; the simulation conditions are:

The vehicle starts to decelerate at 0s, the speed decreases from 20m/s to 10m/s at 0~7s, the vehicle starts to turn at 2s, the front wheel angle is a step signal, and the vehicle speed and front wheel angle are given in Figure 7 (a) As shown in Figure (b), the road surface adhesion coefficient is 0.4;

The yaw rate curves of the uncontrolled vehicle and those controlled by the designed scheme are shown in Figure 8. It can be seen from the figure that when the vehicle step input steering deceleration is not controlled, its yaw rate does not follow the ideal value very well. The ideal value is too small, indicating that the vehicle is understeering; with the chassis integrated control scheme, the yaw rate follows the ideal value very well, basically without deviation, and the lateral driving stability of the vehicle is well guaranteed. The slip ratio of each wheel of the vehicle is shown in Figure 9. It can be seen from the figure that the slip ratio of each wheel is between -0.08 and 0, indicating that the longitudinal motion stability of the vehicle is good.

The vehicle status signal output by the coordinated control system is shown in Figure 10, and the control weights of each subsystem are shown in Figure 11; it can be seen from the figure that the vehicle turns to 4 at 0.6s, at this time AFS, DYC, and ABS control The weights are 0, 0, 1 in turn, and the status signal is switched to 5 at 2.4s. At this time, the control weights of AFS, DYC, and ABS are 1, 0, 1 in turn. From the above analysis, it can be seen that the final front wheel steering angle of the vehicle is 0.12rad, and the vehicle is understeer without control, that is, the working condition of the vehicle is a small understeer condition, which is consistent with the identification results.

Claims (8)

1. A coordinated control device for a chassis integrated control system of a wheel-driven electric vehicle, characterized in that the device includes: a driver's control platform, an attitude parameter ideal value generating unit, a vehicle lateral deviation observation unit, a yaw rate sensor, a vehicle speed sensor , left front wheel speed sensor, right front wheel speed sensor, left rear wheel speed sensor, right rear wheel speed sensor, coordination control unit, AFS controller, ABS controller and DYC controller, wherein, Driver manipulation platform: used to convert driver manipulation instructions into vehicle target speed signal and target angle signal, and simultaneously send the target angle signal to the attitude parameter ideal value generation unit and the coordination control unit, and send the target speed signal to the attitude parameter ideal value generating unit; Attitude parameter ideal value generation unit: used to obtain the target value of yaw rate, center of mass side slip angle and vehicle slip rate target value according to the target speed signal, target corner signal and road surface adhesion coefficient, and send them to the coordination control unit ; Vehicle side slip observation unit: used to observe the side slip angle of the center of mass in real time and send it to the coordination control unit; Yaw rate sensor: used to collect and detect vehicle yaw rate and send it to the coordination control unit; Vehicle speed sensor: used to collect vehicle speed and send it to the coordination control unit; Left front wheel speed sensor: used to collect the left front wheel speed of the vehicle and send it to the coordination control unit; Right front wheel speed sensor: used to collect the speed of the right front wheel of the vehicle and send it to the coordination control unit; Left rear wheel speed sensor: used to collect the left rear wheel speed of the vehicle and send it to the coordination control unit; Right rear wheel speed sensor: used to collect the right rear wheel speed of the vehicle and send it to the coordination control unit; Coordination control unit: used to obtain the front wheel cornering force and the state control signals of the AFS controller, ABS controller and DYC controller according to the collected vehicle speed and target angle signals; and according to the front wheel cornering force and the observed center of mass of the vehicle According to the side slip angle, the fuzzy control output weights of AFS controller, ABS controller and DYC controller are obtained; then according to the state control signals and fuzzy control output weights of AFS controller, ABS controller and DYC controller, the AFS controller’s The control weight value, the control weight value of the ABS controller, and the control weight value of the DYC controller are sent to the AFS controller, the ABS controller, and the DYC controller respectively; finally, according to the collected vehicle speed, vehicle yaw rate, and vehicle center of mass Declination angle, vehicle left front wheel speed, vehicle right front wheel speed, vehicle left rear wheel speed, vehicle right rear wheel speed, target value of yaw rate, target value of side slip angle of center of mass and slip angle of the four wheels of the vehicle shift rate target value, obtain the yaw rate deviation, the center of mass sideslip angle deviation and the slip rate deviation of the four wheels, and send the yaw rate deviation and the center of mass sideslip angle deviation to the AFS controller, and the four wheels The slip rate deviation is sent to the ABS controller, and the yaw rate deviation is sent to the DYC controller; AFS controller: used to obtain the front wheel compensation angle of the vehicle according to the received attitude parameters, the center of mass side slip angle deviation, the yaw rate deviation and the corresponding control weight value, and send it to the vehicle's steering angle motor; ABS controller: used to obtain the tire braking force of the left front wheel, right front wheel, left rear wheel, and right rear wheel of the vehicle according to the received slip ratio deviation of the four wheels of the vehicle and the corresponding control weight value, and send them to the In the left front wheel brake device, right front wheel brake device, left rear wheel brake device, right rear wheel brake device; DYC controller: used to obtain the four wheel motor torque target values according to the received yaw rate deviation and the corresponding control weight value, and send them to the left front wheel hub motor and its control system of the vehicle, and the right front wheel hub respectively Motor and its control system, left rear wheel hub motor and its control system, right rear wheel hub motor and its control system. 2. The coordinated control device of the wheel-driven electric vehicle chassis integrated control system according to claim 1, wherein the coordinated control unit includes: a vehicle state identification unit, a fuzzy coordinated controller, a control logic unit and a deviation generating unit; where, Vehicle state identification unit: used to obtain the front wheel cornering force and the state control signals of the AFS controller, ABS controller and DYC controller according to the collected vehicle speed and target angle signals, and send the front wheel cornering force to the fuzzy coordination In the controller, the state control signals of the AFS controller, ABS controller and DYC controller are sent to the control logic unit; Fuzzy coordination controller: used to obtain the fuzzy control output weights of the AFS controller, ABS controller and DYC controller according to the side cornering force of the front wheels and the observed side slip angle of the vehicle center of mass, and send them to the control logic unit; Control logic unit: used to obtain the control weight value of the AFS controller, the control weight value of the ABS controller and the control of the DYC controller according to the state control signals and fuzzy control output weights of the AFS controller, ABS controller and DYC controller The weight value is sent to the AFS controller, ABS controller and DYC controller respectively; Deviation generating unit: used for collecting vehicle speed, vehicle yaw rate, vehicle side slip angle, vehicle left front wheel speed, vehicle right front wheel speed, vehicle left rear wheel speed, vehicle right rear wheel speed, The target value of the yaw rate, the target value of the sideslip angle of the center of mass and the target value of the slip rate of the four wheels of the vehicle are obtained to obtain the deviation of the yaw rate, the deviation of the side slip angle of the center of mass and the deviation of the slip rate of the four wheels, and the yaw rate The deviation and the side slip angle deviation of the center of mass are sent to the AFS controller, the slip rate deviations of the four wheels are sent to the ABS controller, and the yaw rate deviations are sent to the DYC controller. 3. The control method that adopts the coordinated control device of the integrated control system of the wheel-driven electric vehicle chassis of claim 1, is characterized in that, comprising the following steps: Step 1. The driver's manipulation platform converts the driver's manipulation command into a vehicle target speed signal and a target angle signal, and simultaneously sends the target angle signal to the attitude parameter ideal value generation unit and the coordination control unit, and sends the target speed signal to the attitude parameter ideal value generating unit; Step 2. The attitude parameter ideal value generating unit obtains the target yaw rate value, the target value of the side slip angle of the center of mass and the target value of the slip rate of the vehicle according to the target speed signal, the target corner signal and the road surface adhesion coefficient, and sends them to the coordination control unit ; Step 3, use the vehicle side deviation observation unit to observe the side slip angle of the center of mass in real time, and send it to the coordination control unit; Step 4. Use the yaw angular velocity sensor to collect and detect the vehicle yaw angular velocity, use the vehicle speed sensor to collect the vehicle speed, use the left front wheel speed sensor to collect the vehicle left front wheel speed, and use the right front wheel speed sensor to collect the vehicle right front wheel speed , using the left rear wheel speed sensor to collect the left rear wheel speed of the vehicle, using the right rear wheel speed sensor to collect the right rear wheel speed of the vehicle, and sending the above collected parameters to the coordination control unit; Step 5. The vehicle state identification unit inside the coordination control unit obtains the front wheel cornering force and the state control signals of the AFS controller, ABS controller and DYC controller according to the collected vehicle speed and target angle signals, and calculates the front wheel cornering force The force is sent to the fuzzy coordination controller inside the coordination control unit, and the state control signals of the AFS controller, ABS controller and DYC controller are sent to the control logic unit inside the coordination control unit; Step 6. The fuzzy coordination controller obtains the fuzzy control output weights of the AFS controller, the ABS controller and the DYC controller according to the side cornering force of the front wheels and the observed side slip angle of the vehicle center of mass, and sends them to the control logic unit; Step 7, the control logic unit obtains the control weight value of the AFS controller, the control weight value of the ABS controller and the control of the DYC controller according to the state control signal and the fuzzy control output weight of the AFS controller, ABS controller and DYC controller The weight value is sent to the AFS controller, ABS controller and DYC controller respectively; Step 8. The deviation generating unit inside the coordination control unit is based on the collected vehicle speed, vehicle yaw rate, vehicle side slip angle, vehicle left front wheel speed, vehicle right front wheel speed, vehicle left rear wheel speed, vehicle right Rear wheel speed, yaw rate target value, center of mass sideslip angle target value and the slip rate target value of the four wheels of the vehicle, to obtain the yaw rate deviation, the center of mass side slip angle deviation and the slip rate deviation of the four wheels, And send the yaw rate deviation and the center of mass side slip angle deviation to the AFS controller, send the slip rate deviation of the four wheels to the ABS controller, and send the yaw rate deviation to the DYC controller; Step 9. The AFS controller obtains the vehicle front wheel compensation angle according to the received yaw rate deviation, the center of mass side slip angle deviation and the corresponding control weight value, and sends it to the vehicle's steering angle motor; Step 10. The ABS controller obtains the tire braking forces of the left front wheel, right front wheel, left rear wheel, and right rear wheel of the vehicle according to the received slip ratio deviations of the four wheels and the corresponding control weight values, and sends them to the vehicle respectively In the left front wheel brake device, right front wheel brake device, left rear wheel brake device, right rear wheel brake device; Step 11. The DYC controller obtains the torque target values of the four wheel motors according to the received yaw rate deviation and the corresponding control weight values, and sends them to the left front wheel hub motor and its control system of the vehicle, and the right front wheel hub motor respectively. Motor and its control system, left rear wheel hub motor and its control system, right rear wheel hub motor and its control system. 4. The control method according to claim 3, wherein the attitude parameter ideal value generation unit described in step 2 obtains the yaw rate target value and the four parameters of the vehicle according to the target speed signal, the target corner signal and the road surface adhesion coefficient. Wheel slip rate target value, and sent to the coordination control unit; When the vehicle turns left, that is, δ _d > 0, the specific formula of the target value of the yaw rate is as follows: ${\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}}{\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Kv</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; \&mu;</span>}\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$ When the vehicle turns right, that is, δ _d <0, the specific formula of the target value of the yaw rate is as follows: ${\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}}{\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Kv</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; \&mu;</span>}\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$ ${\mathrm{<span\; class="notranslate">\; \&beta;</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; mv</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}^{<span\; class="notranslate">\; *</span>}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$ Among them, K represents the stability factor, γ* represents the target value of yaw rate, v _d represents the target speed signal, δ _d represents the target corner signal, μ represents the road surface adhesion coefficient, g represents the gravitational acceleration, l=l _r + l _f , l _r represents the distance from the center of mass to the front axle, l _f represents the distance from the center of mass to the rear axle, β ^* represents the target value of the side slip angle of the center of mass, C _f represents the stiffness coefficient of the front wheel tire, and C _r represents the stiffness coefficient of the rear wheel tire ; m represents the mass of the vehicle; The target value of the slip ratio of the four wheels of the vehicle: obtained according to the relationship between the slip ratio of the four wheels of the vehicle and the road surface adhesion coefficient. 5. The control method according to claim 3, wherein the vehicle state identification unit inside the coordination control unit described in step 5 obtains the front wheel lateral force and the AFS controller, The state control signals of the ABS controller and the DYC controller, and send the front wheel cornering force to the fuzzy coordination controller inside the coordination control unit, and send the state control signals of the AFS controller, ABS controller and DYC controller to In the control logic unit inside the coordination control unit; Get front wheel cornering force The specific calculation is as follows: Construct the kinetic differential equation: ${\mathrm{<span\; class="notranslate">\; mv</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; (</span>\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&gamma;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$ $\mathrm{<span\; class="notranslate">\; J</span>}\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$ Among them, m represents the mass of the vehicle, v _x represents the longitudinal velocity of the vehicle, β represents the side slip angle of the observed center of mass, γ represents the yaw rate, F _yfl represents the lateral force of the left front wheel, and F _yfr represents the lateral force of the right front wheel , F _yrl represents the lateral force of the left rear wheel, F _yrr represents the lateral force of the right rear wheel, J represents the moment of inertia of the wheel motor, l _r represents the distance from the center of mass to the front axle, l _f represents the distance from the center of mass to the rear axle, M Indicates the external yaw moment; Simplify formulas (3) and (4), let F _yf =F _yfl +F _yfr , F _yr =F _yrl +F _yrr , get: ma _y =F _yf +F _yr (5) $\mathrm{<span\; class="notranslate">\; J</span>}\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$ Among them, a _y represents the lateral acceleration of the vehicle, F _yf represents the lateral force of the front tire of the monorail model, and F _yr represents the lateral force of the rear tire of the monorail model; Estimate F _yf in formula (5) and formula (6), and obtain the following formula: ${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; ma</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; J</span>}\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$ in, is the estimator of F _yf ; ${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}}_{\mathrm{<span\; class="notranslate">\; N</span>}\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>\frac{{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}\mathrm{<span\; class="notranslate">\; f</span>}}}{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$ Among them, m _f =ml _r /l, l=l _r +l _f ; Obtain the state control signals of the AFS controller, ABS controller and DYC controller, as follows: According to the front wheel angle, the longitudinal deceleration of the vehicle and the steering characteristics of the vehicle, the driving state of the vehicle can be judged, as shown in Table 1: Table 1 Vehicle driving state identification logic In Table 1, δ represents the front wheel rotation angle, δ _thres represents the threshold value of the front wheel rotation angle, a _x represents the longitudinal acceleration of the vehicle, a _xthres represents the threshold value of the longitudinal acceleration, and v _ch represents the characteristic vehicle speed; ${\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$ According to the vehicle driving state in Table 1, the state control signal η of the AFS controller, ABS controller and DYC controller is obtained, as shown in Table 2: Table 2 State control signal list of AFS controller, ABS controller and DYC controller Output the state control signal η of the AFS controller, ABS controller and DYC controller: the eight states are expressed in binary as 000, 001, 010, 011, 100, 101, 110, and 111 are converted into decimals, respectively 0 to 7, as shown in the table In 2, 1 indicates that the controller is working, and 0 indicates that the controller is not working. The value of the status signal is determined by converting the binary code of the working status of each subsystem into decimal under different working conditions. 6. The control method according to claim 3, wherein the fuzzy coordination controller described in step 6 obtains the AFS controller, the ABS controller and the DYC control according to the side slip angle of the center of mass of the front wheel cornering force and observation. The fuzzy control output weight of the device is sent to the control logic unit; details as follows: sideways force on the front wheel The historical data of the center of mass and the historical data of the side slip angle β are used as the input of the fuzzy controller, and the output weight of the fuzzy control ω is used as the output of the fuzzy controller, and the lateral force of the front wheel is obtained through simulation Based on the discourse domain of center of mass sideslip angle β and fuzzy control output weight ω, the fuzzy control rule is obtained, and according to the front wheel lateral force in the fuzzy control rule and the center of mass sideslip angle β to obtain the corresponding fuzzy control output weight ω. 7. control method according to claim 3, is characterized in that, the control logic unit described in step 7 obtains AFS controller according to the state control signal and the fuzzy control output weight of AFS controller, ABS controller and DYC controller The control weight value of the ABS controller, the control weight value of the ABS controller and the control weight value of the DYC controller are sent to the AFS controller, the ABS controller and the DYC controller respectively; According to the eight states output by the vehicle identification unit and the fuzzy control output weight, the control weight value η _AFS of the AFS controller, the control weight value η _ABS of the ABS controller and the control weight value η _DYC of the DYC controller are obtained, as shown in Table 3. ,Table 4: Table 3 Control weight table of AFS controller and DYC controller Table 4 ABS controller control weight table Among them, ω represents the output weight of fuzzy control. 8. The control method according to claim 3, characterized in that, the deviation generation unit inside the coordination control unit described in step 8 is based on the collected vehicle speed, vehicle yaw rate, vehicle center of mass side slip angle, vehicle left front wheel speed, vehicle right front wheel speed, vehicle left rear wheel speed, vehicle right rear wheel speed, target value of yaw rate, target value of side slip angle of center of mass and target value of slip rate of four wheels of vehicle, and obtain yaw Angular velocity deviation, center of mass side slip angle deviation and slip rate deviation of the four wheels, and send the yaw rate deviation and center of mass side slip angle deviation to the AFS controller, and send the slip rate deviation of the four wheels to the ABS control In the controller, the yaw rate deviation is sent to the DYC controller; The specific formula is as follows: $\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; \&gamma;</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&gamma;</span>}\\ {\mathrm{<span\; class="notranslate">\; \&Delta;S</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; S</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; j</span>}}\\ \mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; \&beta;</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&beta;</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$ S _ij =(w _ij Rv)/v (11) Among them, Δγ represents the deviation of yaw rate, γ* represents the target value of yaw rate, γ represents the yaw rate obtained by the yaw rate sensor, ΔS _ij represents the slip rate deviation of the four wheels, and i is f or r, j is r or l, s ^* indicates the target slip ratio of the four wheels of the vehicle, S _ij indicates the road tracking slip rate of the four wheels, Δβ indicates the deviation of the center of mass sideslip angle, β ^* indicates the target value of the center of mass sideslip angle, β Represents the side slip angle of the center of mass obtained by the vehicle lateral deviation observation unit, w _ij represents the wheel speed of the four wheels, R represents the tire radius, and v represents the vehicle speed.