CN110606079B - Layered control vehicle rollover prevention method and multi-shaft distributed driving vehicle - Google Patents

Abstract

The invention discloses a layer-controlled vehicle rollover prevention method and a multi-axle distributed drive vehicle. The layered control structure is adopted, and the upper controller performs joint control of active roll moment and differential braking based on the sliding mode variable structure method. The deviation of inclination angle and the deviation of ideal yaw angular velocity and actual yaw angular velocity are used as input, and output active roll moment and differential braking torque value; the middle-level controller realizes active roll moment in each suspension based on effective set method. Reasonable distribution among the actuators; finally, the lower-level controller performs driving anti-skid control for the wheel slippage that may be caused by the middle-level control, so as to eliminate the negative influence of the vertical force change on the longitudinal force of the wheel. The layered control structure adopted by the present invention can give full play to the advantages of the two anti-rollover methods, and at the same time, combined with the anti-slip control of the vehicle, the driving stability of the vehicle can be further improved.

Description

A layered control vehicle rollover prevention method and multi-axle distributed drive vehicle

technical field

The invention belongs to the technical field of active safety of electric vehicles, and in particular relates to a layer-controlled vehicle rollover prevention method and a multi-axle distributed drive vehicle.

technical background

With the development of the economy, the number of cars around the world continues to grow, the roads become congested, and the danger of car travel increases. According to statistics, there were 15,285 rollover accidents of heavy-duty trucks in the United States in 2016, accounting for only 3.04% of the total number of accidents of this model in the whole year. However, there were as many as 7,285 casualties in rollover accidents, accounting for as high as 47.66%, which is enough to see that the rollover casualty rate of heavy vehicles is quite high. As long as a rollover occurs, there will be almost half of the possibility of casualties.

The lateral stability of the vehicle is an important factor affecting the driving safety of the vehicle. In the case of lateral instability of the vehicle, a rollover accident is likely to occur. It is particularly dangerous. The additional sprung mass brought about by the strong carrying capacity means that the handling stability of the vehicle is reduced, making it prone to rollover accidents when faced with extreme working conditions.

Patent CN109733382A proposes an anti-rollover method based on model predictive control, but this method is only applicable to the anti-rollover control of two-axle vehicles; Patent CN107499271A proposes a passenger car based on electronically controlled air suspension and electronically controlled braking system An anti-rollover control system and method, the method effectively controls the rollover of a passenger car by means of coordinated control of a suspension system and a braking system, and improves the anti-rollover performance of the passenger car. The distribution of the vertical force and the stability control for the possible vehicle slippage caused by the change of the vertical force is not carried out.

SUMMARY OF THE INVENTION

In order to solve the defects involved in the background technology, the present invention provides a layered controlled vehicle rollover prevention method and a multi-axle distributed drive vehicle. The present invention adopts a three-layer layered control method, aiming at a multi-axle distributed drive vehicle, realizes anti-rollover through the joint control of active roll moment and differential braking, simultaneously realizes longitudinal anti-skid control, and avoids the active roll moment in the middle layer. Undesirable effects due to distribution control.

The layered control vehicle rollover prevention method of the present invention comprises the following steps:

Measure the steering wheel angle and speed of the vehicle, and input them to the upper anti-rollover joint control system;

The upper-layer anti-rollover joint control system calculates the active roll moment and the differential braking moment, and uses the calculated active roll moment as the input variable of the middle-layer suspension vertical force optimization distribution system;

The middle-level suspension vertical force optimization distribution system realizes the vertical force distribution for the active suspension actuator;

The lower-level driving and braking anti-skid control system is based on the differential braking torque, aiming at the ideal slip rate, and calculating the driving torque based on the sliding mode variable structure method.

Preferably, the upper-layer anti-rollover joint control system uses the steering wheel angle signal as an input variable, and calculates the output variables ideal roll angle and ideal yaw rate through a vehicle three-degree-of-freedom reference model.

Preferably, the active roll moment is calculated based on a sliding mode variable structure control algorithm with fuzzy gain adjustment.

Preferably, the differential braking torque is calculated based on a sliding mode variable structure control algorithm.

Preferably, the vertical force distribution of the active suspension actuators is specifically the distribution ratio of the active anti-roll moment between the front axle active suspension actuators and the middle and rear axle active suspension actuators, and the left active suspension Control of proportional distribution between the actuator and the right active suspension actuator.

Preferably, the vertical force distribution to the active suspension actuators is achieved based on the active set method.

Preferably, the realization of the vertical force distribution for the active suspension actuator based on the active set method specifically includes the following steps:

Set the total control torque between the front axle and the middle and rear axles, and between the left and right wheels at the initial moment, all of which are equally distributed by the actuators at each wheel;

Determine the constraints of the design variable X of the active set method, which consider the adhesion conditions of the wheels on the good road surface, the lateral load transfer rate requirements, the tension and compression requirements of the vertical dynamic force on the body, and the output requirements of the active roll moment. , and the output capability of the active suspension actuator;

Determine a valid set of constraints among all constraints around an iterative feasible point;

After several iterations, the optimal solution of the objective function under the above constraints is obtained, the objective function is the average relative dynamic load of each tire, the optimal vertical force distribution ratio of the active suspension actuator is obtained, and the left front axle, The vertical control force required by the active suspension actuators of the right front axle, left middle rear axle and right middle rear axle.

Preferably, the calculation of the active roll moment specifically includes the following steps:

其计算过程如下：Calculate the roll angle deviation e and its deviation rate

Its calculation process is as follows:

e=φ ₀ -φ

The exponential reaching law is used to design the linear switching function s of the sliding mode variable structure controller;

In the formula, c is a constant, ε is the switching coefficient, k is the sliding mode switching gain, and c>0, ε>0, k>0;

sgn represents a symbolic function whose expression is:

The final sliding mode controller is designed as;

由基于39DOF车辆模型的上层防侧翻控制系统的控制方程得到：In the formula,

The control equation of the upper-layer anti-rollover control system based on the 39DOF vehicle model is obtained:

Among them, the method of determining the switching coefficient ε is as follows: the domain of discourse of the input variable roll angle deviation e in the fuzzy controller is [0, 15], and the domain of discourse of the output variable switching gain ε is [0, 1.5]; The language value sets of the switching gain ε are all {ZO, PM, PB}, representing {zero, positive, positive} in natural language; the membership function of the input variable and output variable is a triangular-S type mixed membership function, The defuzzification method adopts the area centroid method. Preferably, the lower-level driving and braking anti-skid control system takes the rotation angular velocity corresponding to the slip ratio of 20% as the reference target.

The present invention also relates to a multi-axle distributed drive vehicle, which is characterized by adopting the above-mentioned layered control vehicle rollover prevention method.

The present invention has the following beneficial effects:

1. Using a layered stability control framework, the middle-layer control system can realize the optimal distribution of the active roll moment calculated by the upper-layer control system among the active suspensions of the multi-axle distributed drive vehicle, and the lower-layer control system can target the middle-layer vertical force For the vehicle slippage that may be caused by the change phenomenon and the change of the vertical force of the middle layer, the longitudinal anti-skid control is carried out to avoid the adverse effect of the distribution control of the middle layer, and the comprehensive performance requirements of the vehicle during the driving process are realized.

2. The joint control of active roll moment and differential braking can give full play to the advantages of the two control methods and solve the shortcomings brought by the use of a single method.

Specifically, when the vehicle roll attitude deviation is small, the roll control is not enough to affect the yaw parameters. At this time, the active roll moment system is firstly used for control to give full play to the direct and effective advantages of suspension control, while the When the body roll is more serious, or the active roll moment control obviously changes the vehicle yaw rate change law, the differential braking system participates in the working condition. On the one hand, the negative influence of the control of the rolling moment in the yaw direction is compensated by the action of the differential additional yaw moment.

3. The method based on fuzzy control is used to determine the gain coefficient in the active roll moment sliding mode variable structure control. Compared with the constant switching gain in the traditional sliding mode control system, it can change continuously with the change of the control effect. To a certain extent, the jitter phenomenon in the control process is improved.

4. Taking the roll angle and yaw rate as the reference index of anti-rollover control, compared with selecting the lateral load transfer rate LTR as the index, the roll stability control of the vehicle can be directly realized according to the deviation of the control reference index.

Description of drawings

1 is a schematic diagram of the principle of the layered anti-rollover coordination control system of the present invention

Fig. 2 is a block diagram of the vehicle rollover prevention control principle based on fuzzy-sliding mode control of the present invention

FIG. 3 is a schematic diagram of the optimal allocation process of active roll moment in the active set method of the present invention.

Detailed ways

Below in conjunction with accompanying drawing, the technical scheme of the present invention is described in further detail:

As shown in Figure 1, the layered control structure of the present invention, the upper left corner of the dashed box is the upper-layer anti-rollover joint control system, using a double closed-loop control structure to calculate the active roll moment and the differential braking moment. For the vehicle anti-rollover control, the calculated active roll moment is used as the input variable of the vertical force distribution system of the middle suspension, and the active roll moment is distributed to each active suspension system. The dynamic anti-skid control system optimizes and controls the wheel slip phenomenon that may be caused by the vertical force distribution of the mid-level suspension, and uses the slip rate to control the driving anti-skid control. The control process of the present invention specifically comprises the following steps:

Step 1), measure the steering wheel angle δ _s , vehicle speed v, yaw rate r, roll angle φ of the vehicle, and then input them to the upper-layer anti-rollover joint control system;

The control process of the upper-layer anti-rollover joint control system includes the following steps:

Step 2), taking the steering wheel angle signal δs as the input variable, and calculating the output variables ideal roll angle φ ₀ and ideal yaw rate r ₀ through the vehicle three-degree-of-freedom reference model;

Taking an eight-axis distributed drive vehicle as an example, the specific calculation process of step 2) is as follows:

作为状态变量，即

方向盘转角信号δ_s作为输入变量u，以理想侧倾角φ₀和理想横摆角速度r₀为输出变量y；With roll angle φ, lateral velocity v _y , yaw angular velocity r and roll angular velocity

as a state variable, i.e.

The steering wheel angle signal δ _s is used as the input variable u, and the ideal roll angle φ ₀ and the ideal yaw rate r ₀ are used as the output variable y;

The three-degree-of-freedom vehicle state equation is established as follows:

Where, A=-F ^-1 G, B=F ^-1 HC=[1 0 1 0]

where m and m _s represent the vehicle mass and suspension mass, respectively;

v _x and v _y represent the longitudinal and lateral speeds of the vehicle, respectively;

分别表示侧倾角、侧倾角速度、侧倾角加速度；φ,

respectively represent the roll angle, roll angular velocity, and roll angular acceleration;

表示车辆绕z轴的横摆角速度、横摆角加速度；r.

Indicates the yaw angular velocity and yaw angular acceleration of the vehicle around the z-axis;

I _xz represents the inertia product of the vehicle on the ox and oz axes;

I _x represents the moment of inertia of the vehicle around the x-axis;

I _z represents the moment of inertia of the vehicle around the z-axis;

Li represents the distance from the _i -th axis to the centroid;

C _i represents the roll angle stiffness of the i-th axle suspension;

h represents the distance from the center of gravity of the suspension to the roll axis;

K _si and C _si represent the stiffness and damping of the ith suspension, respectively.

The control equation of the upper anti-rollover control system is established as follows:

Take x _c =[r ω _x ] ^T as the target state variable, where ω _x and r are the state variables corresponding to active roll moment control and differential braking control in the upper-layer anti-rollover joint control system, respectively. Take _uc = [F _X M _X ] ^T as the target control input variable, where F _X represents the differential braking torque, and M _X represents the active roll moment;

The nonlinear state equation is obtained based on the vehicle model to be analyzed, and the control equation is obtained;

The nonlinear state equation is preferably obtained based on the 39DOF vehicle model, and the obtained control equation is as follows:

In the formula, u, _v , vz represent the longitudinal, lateral and vertical speeds of the vehicle, respectively;

ω _x , ω _y , and r represent the rotational angular velocity of the vehicle body around the x-axis, y-axis and z-axis of the vehicle coordinate system, respectively;

F _x , F _y , and F _z represent the longitudinal, lateral and vertical forces of the vehicle at the X, Y, and Z coordinates, respectively;

M _z , M _x , and M _y represent the yaw moment of the vehicle in the directions of the z, x, and y axes, respectively;

M and m _b represent the vehicle and body mass, respectively;

I _x , I _y , and I _z represent the moment of inertia of the vehicle around the x-axis, the y-axis and the z-axis, respectively;

_αs and f are the lane gradient and rolling resistance coefficient, respectively;

C _D and A represent the air resistance coefficient and the windward area, respectively;

φ and ψ represent the roll and pitch angles of the body, respectively;

h _e is the distance from the sprung mass center to the roll center.

Step 3), calculating active roll moment based on the sliding mode variable structure control algorithm of fuzzy gain adjustment;

As shown in Figure 2, the principle block diagram of calculating the active roll moment based on the sliding mode variable structure control algorithm based on fuzzy gain adjustment.

Step 3) The specific steps are as follows:

其计算过程如下：Step 3.1.1), calculate the roll angle deviation e and its deviation rate

Its calculation process is as follows:

e=φ ₀ -φ

Step 3.1.2), select the exponential reaching law to design the linear switching function s of the sliding mode variable structure controller;

In the formula, c is a constant, ε is the switching coefficient, k is the sliding mode switching gain, and c>0, ε>0, k>0;

sign represents a symbolic function whose expression is:

Step 3.1.3), the final sliding mode controller is designed as;

由上述基于39DOF车辆模型的上层防侧翻控制系统的控制方程得到：In the formula,

It is obtained from the above control equation of the upper-layer anti-rollover control system based on the 39DOF vehicle model:

Among them, the fuzzy control method is used to determine the switching coefficient ε in step 3.1.2), and the specific steps are as follows:

Step 3.2), the domain of universe of the input variable roll angle deviation e in the fuzzy controller is [0, 15], and the domain of discourse of the output variable switching gain ε is [0, 1.5]; the language values of the roll angle deviation e and switching gain ε The sets are all {ZO, PM, PB}, which represent {zero, positive, positive} in natural language; the membership functions of the input variables and output variables use the triangular-S type mixed membership function, and the defuzzification method uses the area center of gravity Law.

Step 4), calculate the differential braking torque F _x based on the sliding mode variable structure control algorithm;

Step 4) The specific steps are as follows:

其计算过程如下：Step 4.1), calculate the yaw rate deviation _er and its deviation rate

Its calculation process is as follows:

er = _{r 0} -r

Step 4.2), select the exponential reaching law to design the linear switching function s of the sliding mode variable structure controller;

In the formula, c is a constant, ε is the switching coefficient, k is the sliding mode switching gain, and c>0, ε>0, k>0;

sgn represents a symbolic function whose expression is:

Step 4.3), the final sliding mode controller is designed as;

In the formula, g′ and f′ are obtained from the above control equations of the upper-layer anti-rollover control system based on the 39DOF vehicle model:

Under the action of the above-mentioned upper-layer anti-rollover joint control system, the active roll moment required to prevent the body from rolling over is calculated through fuzzy control-sliding mode variable structure control. The active roll moment can make the vehicle roll angle according to the reference The changing law of the trajectory realizes safe lateral movement.

The control of the total active roll moment on the vehicle system is finally realized by the active suspension actuator, so the vertical force distribution control of the active suspension actuator is realized by the vertical force distribution optimization control system of the mid-level suspension.

The present invention simplifies the vehicle active suspension actuator to each wheel and divides it according to the position of the wheel. It is mainly divided into the left front axle implementation area and the right front axle implementation area that support the driver's cabin, and the left middle rear axle implementation area that carries the cargo. and the execution area of the right middle rear axle. The front axle execution area includes the foregoing left front axle execution area and the right front axle execution area, the middle and rear axle execution area includes the foregoing left middle rear axle execution area and the right middle rear axle execution area, and the left execution area includes the foregoing left front axle execution area and left middle execution area. Rear axle execution area, right execution area includes the aforementioned front right axle execution area and right middle rear axle execution area.

Therefore, the vertical force distribution for the active suspension actuator can be transformed into the distribution ratio of the active anti-roll moment between the front axle execution area and the middle and rear axle execution areas, as well as between the left and right execution areas. Control of distribution ratio. That is, the distribution control of the active suspension actuator can be transformed into the distribution ratio of the active anti-roll moment between the active suspension actuator of the front axle and the active suspension actuator of the middle and rear axle, and the active suspension actuator of the left side. Controls proportional distribution with the right active suspension actuator.

Under the action of active roll moment control, on the one hand, the lateral posture of the body can be effectively adjusted, on the other hand, the dynamic vertical force at the wheels will change. Specifically, the pressure on the compressed side of the suspension increases. , the tension on the tension side increases. Therefore, from the perspective of improving the driving safety, the optimal distribution control is carried out with the goal of reducing the vertical relative dynamic load of the wheel.

The control process of the vertical force distribution optimization system for the mid-level suspension includes the following steps:

Step 5), using the active roll moment calculated in step 3) as the input of the middle-level controller, and based on the active set method, perform an optimal distribution of the active anti-roll moment for each active suspension actuator;

Based on the above active suspension actuator partition, the design variable X is the optimal distribution ratio of active roll moment:

X=[k _x1 ,k _x2 ] ^T

Among them, k _x1 is the torque distribution ratio between the front axle active suspension actuator and the middle rear axle active suspension actuator, and k _x2 is the ratio between the left active suspension actuator and the right active suspension actuator. Torque distribution ratio.

Figure 3 shows the schematic diagram of the effective set method flow chart of the vertical force distribution optimization system of the middle suspension, which specifically includes the following steps:

Step 5.1), set the initial point of the simulation as X=[0.25, 0.5], indicating that the total control torque at the initial moment is the average of the actuators at each wheel between the front axle and the middle and rear axle, and between the left and right wheels. distribute.

具体表达如下：Step 5.2), determine the constraints of the design variable X. The constraint conditions consider the adhesion conditions of the wheels on a good road surface, the lateral load transfer rate requirements, the tension and compression requirements of the vertical dynamic force on the body, the output requirements of the active roll moment, the output capability of the active suspension actuator, etc. The short form of mathematical expression is

The specific expression is as follows:

Among them, F _xi represents the longitudinal force on each wheel, F _zsdi represents the vertical total load at each wheel, μ represents the road adhesion coefficient, F _zli represents the vertical load on the wheel of the i-th axis in the left execution area, F _zri represents the vertical load on the wheel of the i-th axis in the right execution area, ΔF _zi represents the vertical force at each wheel, F _max represents the limit value of the vertical force of a single wheel, K _x1 , K _x1 respectively represent the distribution The boundary limit of the coefficient is affected by the output capacity of the active suspension actuator, n represents the total number of axles, and LTR _max is the maximum lateral load transfer rate;

Step 5.3), determine the effective set of constraints in all constraints around the iterative feasible point;

Step 5.4), after several iterations, the optimal solution X of the objective function under the above constraints is obtained, and the objective function is the average relative dynamic load of each tire, and its expression is as follows:

Among them, F _zdi represents the vertical dynamic load at each wheel of the vehicle, F _zsdi represents the vertical total load at each wheel, and m represents the total number of tires.

Step 5.5), the optimal vertical force distribution ratio of the active suspension actuator is calculated from step 5.4), and the required amount of active suspension actuators for the left front axle, right front axle, left middle rear axle and right middle rear axle is calculated. The vertical control forces ΔF _zfl , ΔF _zfr , ΔF _zrl , and ΔF _zrr are used to control the vertical force of the active suspension. The specific calculation process of the vertical force of each active suspension is as follows:

In the formula, B is the wheelbase;

Through the middle-level optimal distribution of the active roll moment, the optimal moment distribution ratio of the vehicle's active suspension is obtained. Due to the influence of the active suspension control on the vertical force of the wheel, the relative dynamic load of the wheel is reduced, and the vertical safety is Sex is improved. When the vertical force changes due to the control distribution, the longitudinal output capacity of the wheel will inevitably change considering the limiting effect of the vertical force of the tire on the value of the longitudinal force. Aiming at the possible wheel slip caused by the vertical force control of the middle layer, the lower driving and braking anti-skid control system takes the ideal slip rate as the target, and performs the driving anti-skid control based on the sliding mode variable structure method.

The control process of the lower driving and braking anti-skid control system includes the following steps:

Step 6), with the ideal slip rate as the target, the driving torque _Tw is calculated based on the sliding mode variable structure method.

其计算过程如下：Step 6.1), take the rotation angular velocity w ₀ corresponding to 20% slip rate as the reference target, calculate the rotation angular velocity deviation e _w and its deviation rate

Its calculation process is as follows:

e _w =w ₀ -w

Step 6.2), select the exponential reaching law to design the linear switching function s of the sliding mode variable structure controller;

In the formula, c is a constant, ε is the switching coefficient, k is the sliding mode switching gain, and c>0, ε>0, k>0;

sgn represents a symbolic function whose expression is:

Step 6.3), the final sliding mode controller is designed as;

由单个轮胎控制所需状态方程得到：In the formula,

The equation of state required for the control of a single tire is obtained:

Among them, the control output _u '=Tw, the state variable x=ω,

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as herein, are not to be taken in an idealized or overly formal sense. explain.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in further detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. a vehicle rollover prevention method of layered control is characterized in that comprising the steps: Measure the steering wheel angle and speed of the vehicle, and input them to the upper anti-rollover joint control system; The upper-layer anti-rollover joint control system calculates the active roll moment and the differential braking moment, and uses the calculated active roll moment as the input variable of the middle-layer suspension vertical force optimization distribution system; The vertical force distribution system for the middle-level suspension realizes the vertical force distribution for the active suspension actuator, which specifically includes the following steps: Set the total control torque between the front axle and the middle and rear axles, and between the left and right wheels at the initial moment, all of which are equally distributed by the actuators at each wheel; Determine the constraints of the design variable X of the active set method, which consider the adhesion conditions of the wheels on the good road surface, the lateral load transfer rate requirements, the tension and compression requirements of the vertical dynamic force on the body, and the output requirements of the active roll moment. , and the output capability of the active suspension actuator; Determine a valid set of constraints among all constraints around an iterative feasible point; After several iterations, the optimal solution of the objective function under the above constraints is obtained, the objective function is the average relative dynamic load of each tire, the optimal vertical force distribution ratio of the active suspension actuator is obtained, and the left front axle, The vertical control force required by the active suspension actuators of the right front axle, left middle rear axle and right middle rear axle; The lower-level driving and braking anti-skid control system is based on the differential braking torque, aiming at the ideal slip rate, and calculating the driving torque based on the sliding mode variable structure method. 2. The method according to claim 1, characterized in that: the upper-layer anti-rollover joint control system takes the steering wheel angle signal as an input variable, and calculates the output variables ideal roll angle and ideal yaw angular velocity through a vehicle three-degree-of-freedom reference model . 3 . The method of claim 1 , wherein the active roll moment is calculated based on a sliding mode variable structure control algorithm with fuzzy gain adjustment. 4 . 4. The method of claim 1, wherein the differential braking torque is calculated based on a sliding mode variable structure control algorithm. 5. The method according to any one of claims 1 to 4, characterized in that: the vertical force distribution of the active suspension actuator is specifically for the active anti-roll moment between the front axle active suspension actuator and the middle and rear. The control of the distribution ratio between the axle active suspension actuators and the distribution ratio between the left active suspension actuator and the right active suspension actuator. 6. The method according to any one of claims 1 to 4, wherein the vertical force distribution for the active suspension actuator is realized based on an active set method. 7. The method according to any one of claims 1 to 4, wherein the calculating the active roll moment specifically comprises the following steps: Calculate the roll angle deviation e and its deviation rate

Its calculation process is as follows: e=φ ₀ -φ

Among them, φ is the roll angle, and φ ₀ is the ideal roll angle; The exponential reaching law is used to design the linear switching function s of the sliding mode variable structure controller;

In the formula, c is a constant, ε is the switching coefficient, k is the sliding mode switching gain, and c>0, ε>0, k>0; sgn represents a symbolic function whose expression is:

The final sliding mode controller is designed as;

In the formula,

The control equation of the upper-layer anti-rollover control system based on the 39DOF vehicle model is obtained:

in,

For the roll angle acceleration, the fuzzy control method is used to determine the above switching coefficient ε. Specifically, the domain of the input variable roll angle deviation e in the fuzzy controller is [0, 15], and the domain of the output variable switching coefficient ε is [0, 1.5. ]; the language value sets of the roll angle deviation e and the switching coefficient ε are all {ZO, PM, PB}, representing {zero, middle, positive} in natural language; the membership functions of the input variables and output variables are selected from triangular- S-shaped mixed membership function, the defuzzification method adopts the area centroid method. 8. The method according to any one of claims 1 to 4, wherein the lower-layer driving and braking anti-skid control system takes a rotation angular velocity corresponding to a slip ratio of 20% as a reference target. 9. A multi-axle distributed drive vehicle, characterized in that the layered control vehicle rollover prevention method according to any one of claims 1-8 is adopted.

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