A road class based active suspension control system for a vehicle

Abstract

This invention discloses an active suspension control system for automobiles based on road type, belonging to the field of active suspension systems. It aims to solve the control problems of active suspension in automobiles under various conditions such as cornering, obstacle avoidance on straight roads, longitudinal incline crossing, and off-road driving. This invention employs a method of first detecting, then determining the control strategy, and finally controlling the air spring electronic valve and the variable damping shock absorber electronic valve to control the active suspension of the automobile under different operating conditions.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of automobile suspension, relates to the field of vehicle active suspension, and particularly relates to a vehicle active suspension control system based on road types, which is used for improving the comfort and safety of a vehicle during driving. BACKGROUND

[0002] The automobile suspension has a great influence on the steering stability and smoothness of the vehicle during driving, and is classified into active suspension, semi-active suspension and passive suspension. The active suspension has the advantage of adjustable parameters, and has a great effect on improving the steering stability and smoothness of the vehicle, so the active suspension has a wide prospect.

[0003] However, since the driving conditions of the vehicle are very complex, the requirements for the active suspension are quite different when the vehicle drives in different conditions, and the active suspension control method is required to be more strict. The current active suspension control method cannot keep the best comfort of the vehicle in all conditions. SUMMARY

[0004] In view of the above problems, the present application provides a vehicle active suspension control system based on road types, which is used for controlling the active suspension when the vehicle drives in the conditions of curve steering, straight road obstacle avoidance, longitudinal slope passing, off-road and the like, and improving the riding comfort of the vehicle.

[0005] To achieve the above purpose, the technical scheme of the present application is as follows,

[0006] A vehicle active suspension control system based on road types, characterized in that it comprises:

[0007] a road type detection module, a steering type estimation module, a rollover state alarm module, a curve steering control module, a straight road obstacle avoidance control module, a longitudinal slope passing control module and an off-road state control module.

[0008] The road type detection module collects the maximum road curvature within 10 meters in front of the vehicle to determine the road type in front of the vehicle, collects the road support force on the left front suspension, the road support force on the right front suspension, the road support force on the left rear suspension, the road support force on the right rear suspension and the longitudinal acceleration of the vehicle when driving on the road, and uses a longitudinal slope calculation formula to determine the road longitudinal slope at the current position of the vehicle.

[0009] The steering type estimation module collects the steering wheel angular velocity, the vehicle body roll angular acceleration and the brake pedal force, and uses a steering type estimation formula to estimate the steering type of the vehicle.

[0010] The rollover alarm module monitors the wheel speed, left front air suspension pressure, right front air suspension pressure, left rear air suspension pressure, and right rear air suspension pressure during vehicle operation, and uses a rollover alarm formula to determine whether to issue a rollover alarm signal.

[0011] The cornering control module is communicatively connected to the steering type estimation module and the road type detection module. It can obtain the steering type and the maximum curvature of the road within 10 meters in front of the vehicle, and use the height change formula to control the average height of the left front air spring and the left rear air spring, and the average height of the right front air spring and the right rear air spring.

[0012] The straight-line obstacle avoidance control module is communicatively connected to the steering type estimation module and the road type detection module. It can obtain the steering type and the maximum road curvature within 10 meters in front of the vehicle, and control the average damping coefficient of the left front variable damping shock absorber and the left rear variable damping shock absorber, as well as the average damping coefficient of the right front variable damping shock absorber and the right rear variable damping shock absorber using the damping coefficient change formula.

[0013] The longitudinal slope control module includes a vehicle longitudinal height adjustment module and a vehicle longitudinal height dynamic feedback adjustment module, which are communicatively connected to the road type detection module. By acquiring the longitudinal slope of the road at the current position of the vehicle, the module controls the average height of the left front air spring and the right front air spring, as well as the average height of the left rear air spring and the right rear air spring using a longitudinal steep slope height adjustment formula or a longitudinal steep slope height adjustment formula. The module also adjusts the inflation or deflation speed of the left front air spring electronic control valve, the left rear air spring electronic control valve, the right front air spring electronic control valve, and the right rear air spring electronic control valve.

[0014] The off-road state control module includes a road bumpiness judgment module and an off-road height adjustment module. It uses a road bumpiness judgment formula to judge the road bumpiness level, and controls the height of the left front air spring, right front air spring, left rear air spring, and right rear air spring to be in a low, medium, or high position through the off-road height adjustment module.

[0015] Furthermore, the road type detection module includes a road curvature detector and a road longitudinal slope detector. The road curvature detector obtains the maximum road curvature within 10 meters in front of the vehicle, and the road longitudinal slope detector obtains the road longitudinal slope at the current position of the vehicle.

[0016] The road curvature detector includes a vehicle-mounted camera. The camera scans the maximum curvature R1 of the road within 10 meters in front of the vehicle to determine the type of road within that 10-meter radius.

[0017] When |R1|>R 1，critical The road within 10 meters in front of the vehicle is a curve;

[0018] When |R1|≤R 1，critical The road within 10 meters in front of the vehicle is a straight road;

[0019] In the formula, the unit of R1 is m. -1 R 1，critical These are standard values ​​for road types, in meters (m). -1 And R 1，critical >0; R1 is positive when the maximum curvature of the road within 10 meters in front of the vehicle is on a left-turn road; R1 is negative when the maximum curvature of the road within 10 meters in front of the vehicle is on a right-turn road.

[0020] The road longitudinal slope detector includes a pressure sensor on the left front suspension, a pressure sensor on the right front suspension, a pressure sensor on the left rear suspension, a pressure sensor on the right rear suspension, and a vehicle longitudinal acceleration sensor.

[0021] The pressure sensor on the left front suspension obtains the road support force f acting on the left front suspension. fl The pressure sensor on the right front suspension obtains the road support force f acting on the right front suspension. fr The pressure sensor on the left rear suspension obtains the road support force f acting on the left rear suspension. rl The pressure sensor on the right rear suspension obtains the road support force f acting on the right rear suspension. rr The vehicle longitudinal acceleration sensor obtains the longitudinal acceleration 'a' of the vehicle while it is traveling on the road. y The longitudinal slope R2 of the road at the current position of the vehicle is calculated according to the longitudinal slope calculation formula:

[0022]

[0023] In the formula, R² is in radians, and sgn() represents the sign function, when f fl +f fr -f rl -f rr When >0, sgn(f) fl +f fr -f rl -f rr When f = 1, the longitudinal slope of the road at the current location of the car is downhill; fl +f fr -f rl -f rr When = 0, sgn(f fl +f fr -f rl -frr When f = 0, the longitudinal slope of the road at the current position of the vehicle is 0; fl +f fr -f rl -f rr When < 0, sgn(f fl +f fr -f rl -f rr ) = -1, indicating that the longitudinal slope of the road at the current location of the vehicle is uphill;

[0024] When |R2|>R 2，critical The longitudinal slope of the road at the current location of the vehicle is a steep longitudinal slope;

[0025] When R2>R 2，critical The longitudinal slope of the road at the current location of the vehicle is a steep downward slope.

[0026] When R2 < -R 2，critical The longitudinal slope of the road at the current location of the vehicle is a steep longitudinal slope;

[0027] When |R2|≤R 2，critical The longitudinal slope of the road at the current location of the vehicle is a gentle longitudinal slope;

[0028] In the formula, R 2，critical It is the standard value of the longitudinal slope of the road, R 2，critical The unit is radians, and R 2，critical >0; m represents the total mass of the car in kg, and g represents the acceleration due to gravity, taken as g = 9.8 m / s². 2 When the car accelerates, the longitudinal acceleration a y The longitudinal acceleration a is positive when the car decelerates. y , is negative.

[0029] Furthermore, the steering type estimation module can estimate the vehicle steering type according to the steering type estimation formula;

[0030] The steering type estimation module includes a vehicle basic information module, which stores information such as the upper limit of the steering wheel angular velocity, the upper limit of the body yaw rate that keeps the vehicle in a stable condition, and the upper limit of the brake pedal force.

[0031] The steering type estimation module includes a steering wheel angular velocity sensor, a vehicle yaw rate and acceleration sensor, and a brake pedal force sensor. It estimates the steering type P using the steering type estimation formula. S :

[0032]

[0033] In the formula, PS It is a dimensionless value used to determine the steering type of a car;

[0034] β1, β2, and β3 are weighting factors, and appropriate values ​​can be obtained by training a neural network.

[0035] v sw The steering wheel angular velocity obtained by the steering wheel angular velocity sensor is expressed in rad·s. -1 v up The upper limit of the steering wheel angular velocity is given in rad·s. -1 α v The vehicle yaw acceleration is obtained from the vehicle yaw acceleration sensor, and the unit is rad·s. -2 α up The yaw rate acceleration is the upper limit of the vehicle body that keeps the car in a stable operating condition, and its unit is rad·s. -2 F b The brake pedal force obtained by the brake pedal force sensor is expressed in N or F. up The upper limit of the brake pedal force is expressed in N;

[0036] The steering type P S The two situations correspond to two different steering types:

[0037] When P S ≥P critical At that time, the steering type is a sharp turn;

[0038] When P S <P critical At that time, the steering type is a slow turn;

[0039] In the formula, P critical This is the standard value for the steering type, and it is a dimensionless value.

[0040] Furthermore, the rollover alarm module includes an audible alert, wheel speed sensors, a left front air suspension pressure sensor, a right front air suspension pressure sensor, a left rear air suspension pressure sensor, and a right rear air suspension pressure sensor.

[0041] The wheel speed sensor monitors the wheel speed ω during vehicle movement. w When ω w <ω w，critical When the rollover state alarm module does not issue an alarm signal, ω w，critical This is the standard value for wheel speed;

[0042] When the wheel speed ω monitored by the wheel speed sensor w >ω w，criticalAt that time, the rollover status alarm formula is used to determine whether to issue an alarm signal:

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049] Q max =max{Q fl Q fr Q rl Q rr}

[0050] In the formula, F fl F fr F rl F rr These are the left front air suspension pressure, right front air suspension pressure, left rear air suspension pressure, and right rear air suspension pressure monitored by the left front air suspension pressure sensor, the right front air suspension pressure, the left rear air suspension pressure sensor, and the right rear air suspension pressure sensor, respectively, all in N and F. f This represents the average pressure of the left front air suspension and the right front air suspension, in N and F units. r This represents the average pressure of the left and right rear air suspensions, in N and Q. fl Q is the pressure deviation rate of the left front air suspension, a dimensionless value. fr Q is the right front air suspension pressure offset rate, a dimensionless value. rl Q is the pressure deviation rate of the left rear air suspension, a dimensionless value. rr Q is the right rear air suspension pressure offset rate, a dimensionless value. max It is the maximum value of the car suspension pressure deviation rate, which is a dimensionless value;

[0051] When Q max ≤Q critical When the rollover state alarm module does not issue an alarm signal, Q critical It is the standard value of the rollover pressure offset rate, which is a dimensionless value;

[0052] When Q max Q criticalWhen the rollover alarm module issues a rollover alarm signal, the audible prompt will remind the driver to reduce speed or leave the current road.

[0053] Furthermore, the cornering control module includes a left front air spring electronic valve, a right front air spring electronic valve, a left rear air spring electronic valve, and a right rear air spring electronic valve.

[0054] The cornering control module can send inflation or deflation signals to the left front air spring control valve, right front air spring control valve, left rear air spring control valve, and right rear air spring control valve to change the average height of the left front air spring and left rear air spring, and the average height of the right front air spring and right rear air spring.

[0055] The cornering control module is communicatively connected to the steering type estimation module and the road type detection module, and can obtain the steering type P. S and the maximum road curvature R1 within 10 meters in front of the vehicle;

[0056] The cornering control module also includes a vehicle basic information module, which stores information such as the standard vehicle body height.

[0057] When the road type detection module determines that the road type within 10 meters in front of the vehicle is a curve, and the steering type estimator determines that the steering type is a slow turn, i.e., |R1|>R critical And P S <P critical When the vehicle is in a cornering situation, the steering condition control module determines that the vehicle is in a cornering condition and controls the average height of the left front air spring and the left rear air spring, as well as the average height of the right front air spring and the right rear air spring, using the following height change formula:

[0058]

[0059] Δ h =h l -h r

[0060]

[0061]

[0062] In the formula, Δ h The value is the difference between the average height of the left front and left rear air springs and the average height of the right front and right rear air springs, expressed in meters (m) and heights (h). l The average height of the left front air spring and the left rear air spring is expressed in meters (m) and in kilometres (h). fl This refers to the height of the left front air spring, in meters (m) and height (h).rl This refers to the height of the left rear air spring, in meters (m) and height (h). r The height is the average height of the right front air spring and the right rear air spring, in meters (m) and height (h). fr This refers to the height of the right front air spring, in meters (m) and height (h). rr This refers to the height of the right rear air spring, in meters (m) and height (h). v This refers to the standard vehicle body height, in meters (m).

[0063] δ1 and δ2 are weighting factors, and can be trained using a neural network to obtain appropriate values;

[0064] When the road within 10 meters in front of the vehicle is a left turn (R1>0), the average height of the left front air spring and the left rear air spring remains unchanged. The cornering control module sends an inflation signal to the right front air spring control valve and the right rear air spring control valve, increasing the average height of the right front air spring and the right rear air spring. The difference between the average height of the left front air spring and the left rear air spring and the average height of the right front air spring and the right rear air spring is equal to the result of the height change formula.

[0065] When the road within 10 meters in front of the vehicle is a right turn (R1 < 0), the average height of the right front air spring and the right rear air spring remains unchanged. The cornering control module sends an inflation signal to the left front air spring control valve and the left rear air spring control valve, increasing the average height of the left front air spring and the left rear air spring. The difference between the average height of the left front air spring and the left rear air spring and the average height of the right front air spring and the right rear air spring is equal to the result of the height change formula.

[0066] Furthermore, the straight-line obstacle avoidance control module includes a left front variable damping shock absorber electronic control valve, a right front variable damping shock absorber electronic control valve, a left rear variable damping shock absorber electronic control valve, a right rear variable damping shock absorber electronic control valve, and a steering wheel angle sensor.

[0067] The straight-line obstacle avoidance control module can send signals to the electronically controlled valves of the left front variable damping shock absorber, right front variable damping shock absorber, left rear variable damping shock absorber, and right rear variable damping shock absorber to change the average damping coefficients of the left front and left rear variable damping shock absorbers, as well as the average damping coefficients of the right front and right rear variable damping shock absorbers; the steering wheel angle sensor can collect the magnitude and direction of the steering wheel angle.

[0068] The cornering control module is communicatively connected to the steering type estimation module and the road type detection module to obtain the steering type P. S and the maximum road curvature R1 within 10 meters in front of the vehicle;

[0069] The cornering control module also includes a vehicle basic information module, which stores information such as the standard vehicle body height.

[0070] When the road type detection module determines that the road type within 10 meters in front of the vehicle is a straight road, and the steering type estimator determines that the steering type is a sharp turn, i.e., |R1| < R 1，critical And P S >P critical At the same time, the average damping coefficients of the left front variable damping shock absorber and the left rear variable damping shock absorber, and the average damping coefficients of the right front variable damping shock absorber and the right rear variable damping shock absorber are controlled by the following damping coefficient variation formula:

[0071]

[0072] Δ C =Δ C，l -Δ C，r

[0073]

[0074]

[0075] In the formula Δ C It is the difference between the average damping coefficient of the left front and left rear variable damping shock absorbers and the average damping coefficient of the right front and right rear variable damping shock absorbers, in N·(m·s). -1 ) -1 Δ C，l This is the average damping coefficient of the left front variable damping shock absorber and the left rear variable damping shock absorber, in N·(m·s). -1 ) -1 Δ C，fl This is the damping coefficient of the left front variable damper, in N·(m·s). -1 ) -1 Δ C，rl This is the damping coefficient of the left rear variable damper, measured in N·(m·s). -1 ) -1 Δ C，r This is the average damping coefficient of the right front variable damping shock absorber and the right rear variable damping shock absorber, in N·(m·s). -1 ) -1 Δ C，fr This is the damping coefficient of the right front variable damper, measured in N·(m·s). -1 ) -1 Δ C，rr This is the damping coefficient of the right rear variable damper, measured in N·(m·s).-1 ) -1 ;

[0076] θ sw The steering wheel angle is obtained by the steering wheel angle sensor, and the unit is radians. θ represents the steering wheel angle when it rotates counterclockwise. sw >0, sgn(θ) sw When θ = 1, the steering wheel rotates clockwise. sw <0, sgn(θ) sw θ = -1, when the steering wheel is not turning sw =0, sgn(θ) sw ) = 0, m is the total mass of the car in kg, h v This refers to the standard vehicle body height, in meters (m).

[0077] When the steering wheel is turned counterclockwise, the vehicle is in a straight-line obstacle avoidance and left-turn condition. This keeps the average damping coefficient of the left front variable damping shock absorber and the left rear variable damping shock absorber unchanged. The straight-line obstacle avoidance control module sends signals to the electronic control valves of the right front variable damping shock absorber and the right rear variable damping shock absorber, causing the average damping coefficient of the right front variable damping shock absorber and the right rear variable damping shock absorber to decrease. The difference between the average damping coefficient of the left front variable damping shock absorber and the left rear variable damping shock absorber and the average damping coefficient of the right front variable damping shock absorber and the right rear variable damping shock absorber is equal to the result of the damping coefficient change formula.

[0078] When the steering wheel is turned clockwise, the vehicle is in a straight-line obstacle avoidance and right-turn condition. The straight-line obstacle avoidance control module sends signals to the left front variable damping shock absorber electronic control valve and the left rear variable damping shock absorber electronic control valve, causing the average damping coefficient of the left front and left rear variable damping shock absorbers to decrease, while keeping the average damping coefficient of the right front and right rear variable damping shock absorbers unchanged. The difference between the average damping coefficient of the left front and left rear variable damping shock absorbers and the average damping coefficient of the right front and right rear variable damping shock absorbers is equal to the result of the damping coefficient change formula.

[0079] Furthermore, the longitudinal hill-crossing control module includes a vehicle longitudinal height adjustment module and a vehicle longitudinal height dynamic feedback adjustment module;

[0080] The vehicle body longitudinal height adjustment module includes a left front air spring electronic control valve, a left front air spring height sensor, a right front air spring electronic control valve, a right front air spring height sensor, a left rear air spring electronic control valve, a left rear air spring height sensor, a right rear air spring electronic control valve, and a right rear air spring height sensor.

[0081] The vehicle body longitudinal height adjustment module can send inflation or deflation signals to the left front air spring electronic control valve, the right front air spring electronic control valve, the left rear air spring electronic control valve, and the right rear air spring electronic control valve to change the average height of the left front air spring and the right front air spring, and the average height of the left rear air spring and the right rear air spring.

[0082] The vehicle body longitudinal height adjustment module can collect height signals from the left front air spring height sensor, the right front air spring height sensor, the left rear air spring height sensor, and the right rear air spring height sensor;

[0083] The vehicle body longitudinal height adjustment module is communicatively connected to the road type detection module, which can obtain the road longitudinal slope of the current position of the vehicle;

[0084] The vehicle longitudinal height adjustment module also includes a vehicle basic information module, which stores information such as vehicle wheelbase, maximum extension of air springs, and maximum compression of air springs.

[0085] The vehicle body longitudinal height dynamic feedback adjustment module can send rapid inflation or deflation signals to the left front air spring control valve, the right front air spring control valve, the left rear air spring control valve, and the right rear air spring control valve to dynamically adjust the inflation or deflation speed of the left front air spring control valve, the right front air spring control valve, the left rear air spring control valve, and the right rear air spring control valve;

[0086] When the longitudinal slope of the road at the current position of the vehicle is |R2| <R 2,critical When the longitudinal slope of the road at the current position of the vehicle is a gentle longitudinal slope, the longitudinal slope control module and the longitudinal dynamic feedback adjustment module do not work and do not control the difference between the average height of the left front air spring and the right front air spring and the average height of the left rear air spring and the right rear air spring.

[0087] When the longitudinal slope of the road at the current position of the vehicle is R2>R 2,critical When the longitudinal slope of the road at the current position of the vehicle is a steep downward slope, the vehicle body longitudinal height adjustment module sends an inflation signal to the left front air spring electronic control valve and the right front air spring electronic control valve to increase the average height of the left front air spring and the right front air spring, and sends an deflation signal to the left rear air spring electronic control valve and the right rear air spring electronic control valve to decrease the average height of the left rear air spring and the right rear air spring. The difference between the average height of the left front air spring and the right front air spring and the average height of the left rear air spring and the right rear air spring is controlled by the longitudinal steep slope height adjustment formula.

[0088] The formula for adjusting the height of the longitudinal steep slope is as follows:

[0089] When the desired height difference between the front and rear air springs is less than or equal to the sum of the maximum extension and maximum compression of the air springs, the difference between the average height of the left and right front air springs and the average height of the left and right rear air springs is equal to the desired height difference between the front and rear air springs.

[0090] When Δ h,goal ≤Δ l,emax +Δ l,cmax When, make Δ h =Δ h,goal ;

[0091] Where Δ h，goal =l×sin(R2), Δ h =h f -h r ,

[0092] In the formula Δ h，goal The desired height difference between the front and rear air springs is expressed in meters (m), Δ. h，goal >0, l is the wheelbase of the vehicle in meters, and R2 is the longitudinal slope of the road at the current position of the vehicle in radians;

[0093] Δ l，emax This is the maximum extension of the air spring, expressed in meters (m), Δ. l，emax >0, Δ l，cmax This is the maximum compression of the air spring, expressed in meters (m), Δ. l，cmax >0, Δ h The value is the difference between the average height of the left front and right front air springs and the average height of the left rear and right rear air springs, expressed in meters (m) and heights (h). f The average height of the left front air spring and the right front air spring is given in meters (m) and height (h). fl The left front air spring height is measured by the left front air spring height sensor, and the unit is m (m) or h (h). fr The height of the right front air spring is measured by the right front air spring height sensor, in meters (m) and in kilometres (h). r The average height of the left and right rear air springs is given in meters (m) and heights (h). rl The left rear air spring height is measured by the left rear air spring height sensor, and the unit is m (m) or h (h). rr The height of the right rear air spring is collected by the right rear air spring height sensor, and the unit is meters (m).

[0094] When Δ h，goal ≤Δ l，emax+Δ l，cmax and At that time, the vehicle body longitudinal height dynamic feedback adjustment module sends a rapid inflation adjustment signal to the left front air spring electronic control valve and the right front air spring electronic control valve;

[0095] When Δ h，goal ≤Δ l，emax +Δ l，cmax and At that time, the vehicle body longitudinal height dynamic feedback adjustment module sends a slow inflation adjustment signal to the left front air spring electronic control valve and the right front air spring electronic control valve;

[0096] When the desired height difference between the front and rear air springs is greater than the sum of the maximum extension and maximum compression of the air springs, the difference between the average height of the left front and right front air springs and the average height of the left rear and right rear air springs is equal to the sum of the maximum extension and maximum compression of the air springs.

[0097] When Δ h，goal >Δ l，emax +Δ l，cmax When, make Δ h =Δ l，emax +Δ l，cmax ;

[0098] When Δ h，goal >Δ l，emax +Δ l，cmax At that time, the vehicle body longitudinal height dynamic feedback adjustment module sends a rapid inflation adjustment signal to the left front air spring electronic control valve and the right front air spring electronic control valve;

[0099] When the longitudinal slope of the road at the current position of the vehicle is R2 < -R 2，critical When the longitudinal slope of the road at the current position of the vehicle is a steep upward slope, the vehicle body longitudinal height adjustment module sends a release signal to the left front air spring electronic control valve and the right front air spring electronic control valve to reduce the average height of the left front air spring and the right front air spring, and sends an inflation signal to the left rear air spring electronic control valve and the right rear air spring electronic control valve to increase the average height of the left rear air spring and the right rear air spring. The difference between the average height of the left front air spring and the right front air spring and the average height of the left rear air spring and the right rear air spring is controlled by the longitudinal downward slope height adjustment formula.

[0100] The formula for adjusting the height of a steep longitudinal slope is as follows:

[0101] When the desired height difference between the front and rear air springs is greater than or equal to the negative of the sum of the maximum extension and the maximum compression of the air springs, the difference between the average height of the left front and right front air springs and the average height of the left rear and right rear air springs is equal to the desired height difference between the front and rear air springs.

[0102] When Δ h，goal ≥-(Δ l，emax +Δ l，cmax When ), make Δ h =Δ h，goal ;

[0103] In the formula Δ h，goal Δ represents the desired height difference between the front and rear air springs. h，goal <0;

[0104] When Δ h，goal ≥-(Δ l，emax +Δ l，cmax )and At that time, the vehicle body longitudinal height dynamic feedback adjustment module sends a rapid inflation adjustment signal to the left rear air spring electronic control valve and the right rear air spring electronic control valve;

[0105] When Δ h，goal ≥-(Δ l，emax +Δ l，cmax )and At that time, the vehicle body longitudinal height dynamic feedback adjustment module sends a slow inflation adjustment signal to the left rear air spring electronic control valve and the right rear air spring electronic control valve;

[0106] When the desired height difference between the front and rear air springs is less than the negative of the sum of the maximum extension and maximum compression of the air springs, the difference between the average height of the left front and right front air springs and the average height of the left rear and right rear air springs is equal to the negative of the sum of the maximum extension and maximum compression of the air springs.

[0107] When Δ h，goal <-(Δ l，emax +Δ l，cmax When ), make Δ h =-(Δ l，emax +Δ l，cmax );

[0108] When Δ h，goal <-(Δ l，emax +Δ l，cmax When the vehicle body longitudinal height dynamic feedback adjustment module is activated, it sends a rapid inflation adjustment signal to the left rear air spring electronic control valve and the right rear air spring electronic control valve.

[0109] Furthermore, the off-road state control module includes a road bumpiness judgment module and an off-road height adjustment module;

[0110] The road bumpiness determination module includes a left front air spring height sensor, a right front air spring height sensor, a left rear air spring height sensor, and a right rear air spring height sensor.

[0111] The road bumpiness determination module can determine the degree of road bumpiness based on the left front air spring height collected by the left front air spring height sensor, the right front air spring height collected by the right front air spring height sensor, the left rear air spring height collected by the left rear air spring height sensor, and the right rear air spring height collected by the right rear air spring height sensor.

[0112] The off-road height adjustment module includes a left front air spring solenoid valve, a right front air spring solenoid valve, a left rear air spring solenoid valve, and a right rear air spring solenoid valve.

[0113] The off-road height adjustment module also includes a vehicle basic information module, which stores information such as the vehicle's wheel track.

[0114] The off-road height adjustment module can send inflation or deflation signals to the left front air spring control valve, the right front air spring control valve, the left rear air spring control valve, and the right rear air spring control valve, thereby controlling the height of the left front air spring, the right front air spring, the left rear air spring, and the right rear air spring to be in a low, medium, or high position.

[0115] The road bumpiness assessment module determines the degree of road bumpiness using a road bumpiness assessment formula:

[0116]

[0117]

[0118]

[0119]

[0120]

[0121] In the formula, h fl The left front air spring height is measured by the left front air spring height sensor, and the unit is m (m) or h (h). fr The height of the right front air spring is measured by the right front air spring height sensor, in meters (m) and in kilometres (h). fThe height of the left front air spring and the height of the right front air spring are the average values, in meters (m) and heights (h). rl The left rear air spring height is measured by the left rear air spring height sensor, and the unit is m (m) or h (h). rr The height of the right rear air spring is measured by the right rear air spring height sensor, in meters (m) and in kilometres (h). r The value of the left rear air spring height and the right rear air spring height is expressed in meters (m). fl This refers to the degree of change in the height of the left front air spring, which is a dimensionless value, P. fr This refers to the degree of change in the height of the right front air spring, which is a dimensionless value, P. rl This refers to the degree of height change of the left rear air spring, which is a dimensionless value, P. rr P is the degree of change in the height of the right rear air spring, which is a dimensionless value; P is the degree of change in the overall air spring height of the vehicle, which is a dimensionless value; and l2 is the wheelbase of the vehicle, in meters.

[0122] γ1, γ2, γ3, and γ4 are weighting factors, and can be trained using a neural network to obtain appropriate values;

[0123] When P < P low At that time, the road was described as having a gentle bumpy ride;

[0124] When P low <P<P high The road surface described at that time was slightly bumpy.

[0125] When P>P high At that time, the road surface was described as severely bumpy.

[0126] Where P low It is the first standard value for the degree of change in air spring height, and is a dimensionless value, P. high It is the second standard value for the degree of change in air spring height, and it is a dimensionless value.

[0127] When the road surface is relatively smooth, the off-road height adjustment module sends inflation or deflation signals to the left front air spring control valve, the right front air spring control valve, the left rear air spring control valve, and the right rear air spring control valve to control the height of the left front air spring, the right front air spring, the left rear air spring, and the right rear air spring to be in a low position.

[0128] When the road surface is slightly bumpy, the off-road height adjustment module sends inflation or deflation signals to the left front air spring control valve, the right front air spring control valve, the left rear air spring control valve, and the right rear air spring control valve to control the height of the left front air spring, the right front air spring, the left rear air spring, and the right rear air spring to be in the neutral position.

[0129] When the road surface is severely bumpy, the off-road height adjustment module sends inflation or deflation signals to the left front air spring control valve, the right front air spring control valve, the left rear air spring control valve, and the right rear air spring control valve to control the height of the left front air spring, the right front air spring, the left rear air spring, and the right rear air spring to be in a high position.

[0130] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0131] ① It adopts a multi-module electronic control system to control the active suspension of the car under multiple operating conditions. The modules are interconnected, avoiding problems such as incomplete control caused by a single module, and can effectively improve the ride comfort of the car.

[0132] ② A novel judgment method is adopted. The maximum curvature of the road within 10 meters in front of the car is used to determine whether the road ahead is straight or curved. The longitudinal slope of the road at the current position of the car is determined by collecting the road support force on each suspension and the longitudinal acceleration of the car when it is driving on the road. The rollover warning signal is determined by collecting the pressure of each air suspension. The degree of road bumpiness is determined by collecting the change in the height of each air spring. Attached Figure Description

[0133] The invention will now be further described with reference to the accompanying drawings:

[0134] Figure 1 This is a schematic diagram of the proposed active suspension control system. Detailed Implementation

[0135] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0136] Referring to the attached diagram, the entire system includes a road type detection module, a steering type estimation module, a rollover status alarm module, a curve steering control module, a straight road obstacle avoidance control module, a longitudinal slope crossing control module, and an off-road status control module. The road type detection module, steering type estimation module, and rollover status alarm module constitute the detection components; the curve steering control module, straight road obstacle avoidance control module, longitudinal slope crossing control module, and off-road status control module constitute the control components.

[0137] The road type detection module determines the road type by collecting the maximum road curvature within 10 meters in front of the vehicle. It also determines the road's longitudinal slope by collecting data on the road support forces on the left front, right front, left rear, and right rear suspensions, as well as the vehicle's longitudinal acceleration while driving. The steering type estimation module estimates the vehicle's steering type using a formula based on data collected from the steering wheel angular velocity, vehicle yaw acceleration, and brake pedal force. Finally, the rollover alarm module monitors wheel speed, left front air suspension pressure, right front air suspension pressure, left rear air suspension pressure, and right rear air suspension pressure, using a formula to determine whether to issue a rollover alarm signal. The cornering control module, which is communicatively connected to the steering type estimation module and the road type detection module, can obtain the steering type and the maximum road curvature within 10 meters in front of the vehicle. It then uses a height variation formula to control the average heights of the left front and left rear air springs, and the right front and right rear air springs. Similarly, the straight-line obstacle avoidance control module, also communicatively connected to the steering type estimation module and the road type detection module, can obtain the steering type and the maximum road curvature within 10 meters in front of the vehicle. It then uses a damping coefficient variation formula to control the average damping coefficients of the left front and left rear variable damping shock absorbers, and the right front and right rear variable damping shock absorbers. The longitudinal slope control module includes a vehicle longitudinal height adjustment module and a vehicle longitudinal height dynamic feedback adjustment module, which are communicatively connected to the road type detection module. By acquiring the longitudinal slope of the road at the vehicle's current position, it controls the average height of the left and right front air springs, and the average height of the left and right rear air springs using a longitudinal steep slope height adjustment formula or a longitudinal steep slope height adjustment formula. It also adjusts the inflation or deflation speed of the left and right front and right rear air spring electronic control valves. The off-road state control module includes a road bumpiness judgment module and an off-road height adjustment module. It judges the road bumpiness level using a road bumpiness judgment formula and controls the height of the left and right front, left and right rear air springs to be in a low, medium, or high position using the off-road height adjustment module.

[0138] The detection section is divided into a road type detection module, a steering type estimation module, and a rollover status alarm module. The road type detection module mainly includes a road curvature detector and a road longitudinal slope detector. The road curvature detector includes an onboard camera. The onboard camera scans the maximum road curvature R1 within 10 meters in front of the vehicle to determine the road type within that 10-meter radius.

[0139] When |R1|>R 1，critical The road within 10 meters in front of the vehicle is a curve;

[0140] When |R1|≤R i，critical The road within 10 meters in front of the vehicle is a straight road;

[0141] In the formula, the unit of R1 is m. -1 R i，critical These are standard values ​​for road types, in meters (m). -1 And R 1，critical >0; R1 is positive when the maximum curvature of the road within 10 meters in front of the vehicle is on a left-turn road; R1 is negative when the maximum curvature of the road within 10 meters in front of the vehicle is on a right-turn road.

[0142] The road longitudinal slope detector includes a pressure sensor on the left front suspension, a pressure sensor on the right front suspension, a pressure sensor on the left rear suspension, a pressure sensor on the right rear suspension, and a vehicle longitudinal acceleration sensor.

[0143] The pressure sensor on the left front suspension obtains the road support force f acting on the left front suspension. fl The pressure sensor on the right front suspension obtains the road support force f acting on the right front suspension. fr The pressure sensor on the left rear suspension obtains the road support force f acting on the left rear suspension. rl The pressure sensor on the right rear suspension obtains the road support force f acting on the right rear suspension. rr The vehicle longitudinal acceleration sensor obtains the longitudinal acceleration 'a' of the vehicle while it is traveling on the road. y The longitudinal slope R2 of the road at the current position of the vehicle is calculated according to the longitudinal slope calculation formula:

[0144]

[0145] In the formula, R² is in radians, and sgn() represents the sign function, when f fl +f fr -f rl -f rr When >0, sgn(f) fl +f fr-f rl -f rr When f = 1, the longitudinal slope of the road at the current location of the car is downhill; fl +f fr -f rl -f rr When = 0, sgn(f fl +f fr -f rl -f rr When f = 0, the longitudinal slope of the road at the current position of the vehicle is 0; fl +f fr -f rl -f rr When < 0, sgn(f fl +f fr -f rl -f rr ) = -1, indicating that the longitudinal slope of the road at the current location of the vehicle is uphill;

[0146] When |R2|>R 2，critical The longitudinal slope of the road at the current location of the vehicle is a steep longitudinal slope;

[0147] When R2>R 2，critical The longitudinal slope of the road at the current location of the vehicle is a steep downward slope.

[0148] When R2 < -R 2，critical The longitudinal slope of the road at the current location of the vehicle is a steep longitudinal slope;

[0149] When |R2|≤R 2，critical The longitudinal slope of the road at the current location of the vehicle is a gentle longitudinal slope;

[0150] In the formula, R 2，critical It is the standard value of the longitudinal slope of the road, R 2，critical The unit is radians, and R 2，critical >0; m represents the total mass of the car in kg, and g represents the acceleration due to gravity, taken as g = 9.8 m / s². 2 When the car accelerates, the longitudinal acceleration a y The longitudinal acceleration a is positive when the car decelerates. y It is negative.

[0151] For the steering type estimation module, the steering type estimation module can estimate the vehicle steering type according to the steering type estimation formula;

[0152] The steering type estimation module includes a vehicle basic information module, which stores information such as the upper limit of the steering wheel angular velocity, the upper limit of the body yaw rate that keeps the vehicle in a stable condition, and the upper limit of the brake pedal force.

[0153] The steering type estimation module includes a steering wheel angular velocity sensor, a vehicle yaw rate and acceleration sensor, and a brake pedal force sensor. It estimates the steering type P using the steering type estimation formula. S :

[0154]

[0155] In the formula, P S It is a dimensionless value used to determine the steering type of a car;

[0156] β1, β2, and β3 are weighting factors, and appropriate values ​​can be obtained by training a neural network.

[0157] v sw The steering wheel angular velocity obtained by the steering wheel angular velocity sensor is expressed in rad·s. -1 v up The upper limit of the steering wheel angular velocity is given in rad·s. -1 α v The vehicle yaw acceleration is obtained from the vehicle yaw acceleration sensor, and the unit is rad·s. -2 α up The yaw rate acceleration is the upper limit of the vehicle body that keeps the car in a stable operating condition, and its unit is rad·s. -2 F b The brake pedal force obtained by the brake pedal force sensor is expressed in N or F. up The upper limit of the brake pedal force is expressed in N;

[0158] The steering type P S The two situations correspond to two different steering types:

[0159] When P S ≥P critical At that time, the steering type is a sharp turn;

[0160] When P S <P critical At that time, the steering type is a slow turn;

[0161] In the formula, P critical This is the standard value for the steering type, and it is a dimensionless value.

[0162] For the rollover alarm module, the rollover alarm module includes an audible alert, wheel speed sensors, left front air suspension pressure sensors, right front air suspension pressure sensors, left rear air suspension pressure sensors, and right rear air suspension pressure sensors.

[0163] The wheel speed sensor monitors the wheel speed ω during vehicle movement. w When ω w <ω w，critical When the rollover state alarm module does not issue an alarm signal, ω w，critical This is the standard value for wheel speed;

[0164] When the wheel speed ω monitored by the wheel speed sensor w >ω w，critical At that time, the rollover status alarm formula is used to determine whether to issue an alarm signal:

[0165]

[0166]

[0167]

[0168]

[0169]

[0170]

[0171] Q max =max{Q fl Q fr Q rl Q rr}

[0172] In the formula, F fl F fr F rl F rr These are the left front air suspension pressure, right front air suspension pressure, left rear air suspension pressure, and right rear air suspension pressure monitored by the left front air suspension pressure sensor, the right front air suspension pressure, the left rear air suspension pressure sensor, and the right rear air suspension pressure sensor, respectively, all in N and F. f This represents the average pressure of the left front air suspension and the right front air suspension, in N and F units. r This represents the average pressure of the left and right rear air suspensions, in N and Q. fl Q is the pressure deviation rate of the left front air suspension, a dimensionless value. fr Q is the right front air suspension pressure offset rate, a dimensionless value. rl Q is the pressure deviation rate of the left rear air suspension, a dimensionless value. rr Q is the right rear air suspension pressure offset rate, a dimensionless value. max It is the maximum value of the car suspension pressure deviation rate, which is a dimensionless value;

[0173] When Q max ≤Q critical When the rollover state alarm module does not issue an alarm signal, Q critical It is the standard value of the rollover pressure offset rate, which is a dimensionless value;

[0174] When Q max Q critical When the rollover alarm module issues a rollover alarm signal, the audible prompt will remind the driver to reduce speed or leave the current road.

[0175] The control section is divided into a cornering control module, a straight-line obstacle avoidance control module, a longitudinal hill-climbing control module, and an off-road state control module. The cornering control module includes a left front air spring electronic valve, a right front air spring electronic valve, a left rear air spring electronic valve, and a right rear air spring electronic valve.

[0176] The cornering control module can send inflation or deflation signals to the left front air spring control valve, right front air spring control valve, left rear air spring control valve, and right rear air spring control valve to change the average height of the left front air spring and left rear air spring, and the average height of the right front air spring and right rear air spring.

[0177] The cornering control module is communicatively connected to the steering type estimation module and the road type detection module, and can obtain the steering type PS and the maximum road curvature R1 within 10 meters in front of the vehicle.

[0178] The cornering control module also includes a vehicle basic information module, which stores information such as the standard vehicle body height.

[0179] When the road type detection module determines that the road type within 10 meters in front of the vehicle is a curve, and the steering type estimator determines that the steering type is a slow turn, i.e., |R1|>R critical And P S <P critical When the vehicle is in a cornering situation, the steering condition control module determines that the vehicle is in a cornering condition and controls the average height of the left front air spring and the left rear air spring, as well as the average height of the right front air spring and the right rear air spring, using the following height change formula:

[0180]

[0181] Δ h =h l -h r

[0182]

[0183]

[0184] In the formula, Δ h The value is the difference between the average height of the left front and left rear air springs and the average height of the right front and right rear air springs, expressed in meters (m) and heights (h). l The average height of the left front air spring and the left rear air spring is expressed in meters (m) and in kilometres (h). fl This refers to the height of the left front air spring, in meters (m) and height (h). rl This refers to the height of the left rear air spring, in meters (m) and height (h). r The height is the average height of the right front air spring and the right rear air spring, in meters (m) and height (h). fr This refers to the height of the right front air spring, in meters (m) and height (h). rr This refers to the height of the right rear air spring, in meters (m) and height (h). v This refers to the standard vehicle body height, in meters (m).

[0185] δ1 and δ2 are weighting factors, and can be trained using a neural network to obtain appropriate values;

[0186] When the road within 10 meters in front of the vehicle is a left turn (R1>0), the average height of the left front air spring and the left rear air spring remains unchanged. The cornering control module sends an inflation signal to the right front air spring control valve and the right rear air spring control valve, increasing the average height of the right front air spring and the right rear air spring. The difference between the average height of the left front air spring and the left rear air spring and the average height of the right front air spring and the right rear air spring is equal to the result of the height change formula.

[0187] When the road within 10 meters in front of the vehicle is a right turn (R1 < 0), the average height of the right front air spring and the right rear air spring remains unchanged. The cornering control module sends an inflation signal to the left front air spring control valve and the left rear air spring control valve, increasing the average height of the left front air spring and the left rear air spring. The difference between the average height of the left front air spring and the left rear air spring and the average height of the right front air spring and the right rear air spring is equal to the result of the height change formula.

[0188] For the straight-line obstacle avoidance control module, the straight-line obstacle avoidance control module includes a left front variable damping shock absorber electronic control valve, a right front variable damping shock absorber electronic control valve, a left rear variable damping shock absorber electronic control valve, a right rear variable damping shock absorber electronic control valve, and a steering wheel angle sensor.

[0189] The straight-line obstacle avoidance control module can send signals to the electronically controlled valves of the left front variable damping shock absorber, right front variable damping shock absorber, left rear variable damping shock absorber, and right rear variable damping shock absorber to change the average damping coefficients of the left front and left rear variable damping shock absorbers, as well as the average damping coefficients of the right front and right rear variable damping shock absorbers; the steering wheel angle sensor can collect the magnitude and direction of the steering wheel angle.

[0190] The cornering control module is communicatively connected to the steering type estimation module and the road type detection module to obtain the steering type PS and the maximum road curvature R1 within 10 meters in front of the vehicle.

[0191] The cornering control module also includes a vehicle basic information module, which stores information such as the standard vehicle body height.

[0192] When the road type detection module determines that the road type within 10 meters in front of the vehicle is a straight road, and the steering type estimator determines that the steering type is a sharp turn, i.e., |R1| < R 1，critical And P S >P critical At the same time, the average damping coefficients of the left front variable damping shock absorber and the left rear variable damping shock absorber, and the average damping coefficients of the right front variable damping shock absorber and the right rear variable damping shock absorber are controlled by the following damping coefficient variation formula:

[0193]

[0194] Δ C =Δ C，l -Δ C，r

[0195]

[0196]

[0197] In the formula Δ C It is the difference between the average damping coefficient of the left front and left rear variable damping shock absorbers and the average damping coefficient of the right front and right rear variable damping shock absorbers, in N·(m·s). -1 ) -1 Δ C，l This is the average damping coefficient of the left front variable damping shock absorber and the left rear variable damping shock absorber, in N·(m·s). -1 ) -1 Δ C，fl This is the damping coefficient of the left front variable damper, in N·(m·s). -1 ) -1 ΔC，rl This is the damping coefficient of the left rear variable damper, measured in N·(m·s). -1 ) -1 Δ C，r This is the average damping coefficient of the right front variable damping shock absorber and the right rear variable damping shock absorber, in N·(m·s). -1 ) -1 Δ C，fr This is the damping coefficient of the right front variable damper, measured in N·(m·s). -1 ) -1 Δ C，rr This is the damping coefficient of the right rear variable damper, measured in N·(m·s). -1 ) -1 ;

[0198] θ sw The steering wheel angle is obtained by the steering wheel angle sensor, and the unit is radians. θ represents the steering wheel angle when it rotates counterclockwise. sw >0, sgn(θ) sw When θ = 1, the steering wheel rotates clockwise. sw <0, sgn(θ) sw θ = -1, when the steering wheel is not turning sw =0, sgn(θ) sw ) = 0, m is the total mass of the car in kg, h v This refers to the standard vehicle body height, in meters (m).

[0199] When the steering wheel is turned counterclockwise, the vehicle is in a straight-line obstacle avoidance and left-turn condition. This keeps the average damping coefficient of the left front variable damping shock absorber and the left rear variable damping shock absorber unchanged. The straight-line obstacle avoidance control module sends signals to the electronic control valves of the right front variable damping shock absorber and the right rear variable damping shock absorber, causing the average damping coefficient of the right front variable damping shock absorber and the right rear variable damping shock absorber to decrease. The difference between the average damping coefficient of the left front variable damping shock absorber and the left rear variable damping shock absorber and the average damping coefficient of the right front variable damping shock absorber and the right rear variable damping shock absorber is equal to the result of the damping coefficient change formula.

[0200] When the steering wheel is turned clockwise, the vehicle is in a straight-line obstacle avoidance and right-turn condition. The straight-line obstacle avoidance control module sends signals to the left front variable damping shock absorber electronic control valve and the left rear variable damping shock absorber electronic control valve, causing the average damping coefficient of the left front and left rear variable damping shock absorbers to decrease, while keeping the average damping coefficient of the right front and right rear variable damping shock absorbers unchanged. The difference between the average damping coefficient of the left front and left rear variable damping shock absorbers and the average damping coefficient of the right front and right rear variable damping shock absorbers is equal to the result of the damping coefficient change formula.

[0201] For the longitudinal hill-crossing control module, the longitudinal hill-crossing control module includes a vehicle longitudinal height adjustment module and a vehicle longitudinal height dynamic feedback adjustment module;

[0202] The vehicle body longitudinal height adjustment module includes a left front air spring electronic control valve, a left front air spring height sensor, a right front air spring electronic control valve, a right front air spring height sensor, a left rear air spring electronic control valve, a left rear air spring height sensor, a right rear air spring electronic control valve, and a right rear air spring height sensor.

[0203] The vehicle body longitudinal height adjustment module can send inflation or deflation signals to the left front air spring electronic control valve, the right front air spring electronic control valve, the left rear air spring electronic control valve, and the right rear air spring electronic control valve to change the average height of the left front air spring and the right front air spring, and the average height of the left rear air spring and the right rear air spring.

[0204] The vehicle body longitudinal height adjustment module can collect height signals from the left front air spring height sensor, the right front air spring height sensor, the left rear air spring height sensor, and the right rear air spring height sensor;

[0205] The vehicle body longitudinal height adjustment module is communicatively connected to the road type detection module, which can obtain the road longitudinal slope of the current position of the vehicle;

[0206] The vehicle longitudinal height adjustment module also includes a vehicle basic information module, which stores information such as vehicle wheelbase, maximum extension of air springs, and maximum compression of air springs.

[0207] The vehicle body longitudinal height dynamic feedback adjustment module can send rapid inflation or deflation signals to the left front air spring control valve, the right front air spring control valve, the left rear air spring control valve, and the right rear air spring control valve to dynamically adjust the inflation or deflation speed of the left front air spring control valve, the right front air spring control valve, the left rear air spring control valve, and the right rear air spring control valve;

[0208] When the longitudinal slope of the road at the current position of the vehicle is |R2| < R 2，critical When the longitudinal slope of the road at the current position of the vehicle is a gentle longitudinal slope, the longitudinal slope control module and the longitudinal dynamic feedback adjustment module do not work and do not control the difference between the average height of the left front air spring and the right front air spring and the average height of the left rear air spring and the right rear air spring.

[0209] When the longitudinal slope of the road at the current position of the vehicle is R2>R 2，critical When the longitudinal slope of the road at the current position of the vehicle is a steep downward slope, the vehicle body longitudinal height adjustment module sends an inflation signal to the left front air spring electronic control valve and the right front air spring electronic control valve to increase the average height of the left front air spring and the right front air spring, and sends an deflation signal to the left rear air spring electronic control valve and the right rear air spring electronic control valve to decrease the average height of the left rear air spring and the right rear air spring. The difference between the average height of the left front air spring and the right front air spring and the average height of the left rear air spring and the right rear air spring is controlled by the longitudinal steep slope height adjustment formula.

[0210] The formula for adjusting the height of the longitudinal steep slope is as follows:

[0211] When the desired height difference between the front and rear air springs is less than or equal to the sum of the maximum extension and maximum compression of the air springs, the difference between the average height of the left and right front air springs and the average height of the left and right rear air springs is equal to the desired height difference between the front and rear air springs.

[0212] When Δ h，goal ≤Δ l，emax +Δ l，cmax When, make Δh = Δ h，goal ;

[0213] Where Δ h，goal =l×sin(R2), Δ h =h f -h r ,

[0214] In the formula Δ h，goal The desired height difference between the front and rear air springs is expressed in meters (m), Δ. h，goal >0, l is the wheelbase of the vehicle in meters, and R2 is the longitudinal slope of the road at the current position of the vehicle in radians;

[0215] Δ l，emax This is the maximum extension of the air spring, expressed in meters (m), Δ. l，emax >0, Δl，cmax This is the maximum compression of the air spring, expressed in meters (m), Δ. l，cmax >0, Δ h The difference between the average height of the left front and right front air springs and the average height of the left rear and right rear air springs, in meters (m) and heights (h). f The average height of the left front air spring and the right front air spring is given in meters (m) and height (h). fl The left front air spring height is measured by the left front air spring height sensor, and the unit is m (m) or h (h). fr The height of the right front air spring is measured by the right front air spring height sensor, in meters (m) and in kilometres (h). r The average height of the left and right rear air springs is given in meters (m) and heights (h). rl The left rear air spring height is measured by the left rear air spring height sensor, and the unit is m (m) or h (h). rr The height of the right rear air spring is collected by the right rear air spring height sensor, in meters.

[0216] When Δ h，goal ≤Δ l，emax +Δ l，cmax and At that time, the vehicle body longitudinal height dynamic feedback adjustment module sends a rapid inflation adjustment signal to the left front air spring electronic control valve and the right front air spring electronic control valve;

[0217] When Δ h，goal ≤Δ l，emax +Δ l，cmax and At that time, the vehicle body longitudinal height dynamic feedback adjustment module sends a slow inflation adjustment signal to the left front air spring electronic control valve and the right front air spring electronic control valve;

[0218] When the desired height difference between the front and rear air springs is greater than the sum of the maximum extension and maximum compression of the air springs, the difference between the average height of the left front and right front air springs and the average height of the left rear and right rear air springs is equal to the sum of the maximum extension and maximum compression of the air springs.

[0219] When Δ h，goal >Δ l，emax +Δ l，cmax When, make Δ h =Δ l，emax +Δ l，cmax ;

[0220] When Δ h，goal >Δ l，emax +Δ l，cmaxAt that time, the vehicle body longitudinal height dynamic feedback adjustment module sends a rapid inflation adjustment signal to the left front air spring electronic control valve and the right front air spring electronic control valve;

[0221] When the longitudinal slope of the road at the current position of the vehicle is R2 < -R 2，critical When the longitudinal slope of the road at the current position of the vehicle is a steep upward slope, the vehicle body longitudinal height adjustment module sends a release signal to the left front air spring electronic control valve and the right front air spring electronic control valve to reduce the average height of the left front air spring and the right front air spring, and sends an inflation signal to the left rear air spring electronic control valve and the right rear air spring electronic control valve to increase the average height of the left rear air spring and the right rear air spring. The difference between the average height of the left front air spring and the right front air spring and the average height of the left rear air spring and the right rear air spring is controlled by the longitudinal downward slope height adjustment formula.

[0222] The formula for adjusting the height of a steep longitudinal slope is as follows:

[0223] When the desired height difference between the front and rear air springs is greater than or equal to the negative of the sum of the maximum extension and the maximum compression of the air springs, the difference between the average height of the left front and right front air springs and the average height of the left rear and right rear air springs is equal to the desired height difference between the front and rear air springs.

[0224] When Δ h，goal ≥-(Δ l，emax +Δ l，cmax When ), make Δ h =Δ h，goal ;

[0225] In the formula Δ h，goal Δ represents the desired height difference between the front and rear air springs. h，goal <0;

[0226] When Δ h，goal ≥-(Δ l，emax +Δ l，cmax )and At that time, the vehicle body longitudinal height dynamic feedback adjustment module sends a rapid inflation adjustment signal to the left rear air spring electronic control valve and the right rear air spring electronic control valve;

[0227] When Δ h，goal ≥-(Δ l，emax +Δ l，cmax )and At that time, the vehicle body longitudinal height dynamic feedback adjustment module sends a slow inflation adjustment signal to the left rear air spring electronic control valve and the right rear air spring electronic control valve;

[0228] When the desired height difference between the front and rear air springs is less than the negative of the sum of the maximum extension and maximum compression of the air springs, the difference between the average height of the left front and right front air springs and the average height of the left rear and right rear air springs is equal to the negative of the sum of the maximum extension and maximum compression of the air springs.

[0229] When Δ h，goal <-(Δ l，emax +Δ l，cmax When ), make Δ h =-(Δ l，emax +Δ l，cmax );

[0230] When Δ h，goal <-(Δ l，emax +Δ l，cmax When the vehicle body longitudinal height dynamic feedback adjustment module is activated, it sends a rapid inflation adjustment signal to the left rear air spring electronic control valve and the right rear air spring electronic control valve.

[0231] The off-road condition control module includes a road bumpiness judgment module and an off-road height adjustment module.

[0232] The road bumpiness determination module includes a left front air spring height sensor, a right front air spring height sensor, a left rear air spring height sensor, and a right rear air spring height sensor.

[0233] The road bumpiness determination module can determine the degree of road bumpiness based on the left front air spring height collected by the left front air spring height sensor, the right front air spring height collected by the right front air spring height sensor, the left rear air spring height collected by the left rear air spring height sensor, and the right rear air spring height collected by the right rear air spring height sensor.

[0234] The off-road height adjustment module includes a left front air spring solenoid valve, a right front air spring solenoid valve, a left rear air spring solenoid valve, and a right rear air spring solenoid valve.

[0235] The off-road height adjustment module also includes a vehicle basic information module, which stores information such as the vehicle's wheel track.

[0236] The off-road height adjustment module can send inflation or deflation signals to the left front air spring control valve, the right front air spring control valve, the left rear air spring control valve, and the right rear air spring control valve, thereby controlling the height of the left front air spring, the right front air spring, the left rear air spring, and the right rear air spring to be in a low, medium, or high position.

[0237] The road bumpiness assessment module determines the degree of road bumpiness using a road bumpiness assessment formula:

[0238]

[0239]

[0240]

[0241]

[0242]

[0243] In the formula, h fl The left front air spring height is measured by the left front air spring height sensor, and the unit is m (m) or h (h). fr The height of the right front air spring is measured by the right front air spring height sensor, in meters (m) and in kilometres (h). f The height of the left front air spring and the height of the right front air spring are the average values, in meters (m) and heights (h). rl The left rear air spring height is measured by the left rear air spring height sensor, and the unit is m (m) or h (h). rr The height of the right rear air spring is measured by the right rear air spring height sensor, in meters (m) and in kilometres (h). r The value of the left rear air spring height and the right rear air spring height is expressed in meters (m). fl This refers to the degree of change in the height of the left front air spring, which is a dimensionless value, P. fr This refers to the degree of change in the height of the right front air spring, which is a dimensionless value, P. rl This refers to the degree of height change of the left rear air spring, which is a dimensionless value, P. rr P is the degree of change in the height of the right rear air spring, which is a dimensionless value; P is the degree of change in the overall air spring height of the vehicle, which is a dimensionless value; and l2 is the wheelbase of the vehicle, in meters.

[0244] γ1, γ2, γ3, and γ4 are weighting factors, and can be trained using a neural network to obtain appropriate values;

[0245] When P < P low At that time, the road was described as having a gentle bumpy ride;

[0246] When P low <P<P high The road surface described at that time was slightly bumpy.

[0247] When P>P high At that time, the road surface was described as severely bumpy.

[0248] Where P low It is the first standard value for the degree of change in air spring height, and is a dimensionless value, P. high It is the second standard value for the degree of change in air spring height, and it is a dimensionless value.

[0249] When the road surface is relatively smooth, the off-road height adjustment module sends inflation or deflation signals to the left front air spring control valve, the right front air spring control valve, the left rear air spring control valve, and the right rear air spring control valve to control the height of the left front air spring, the right front air spring, the left rear air spring, and the right rear air spring to be in a low position.

[0250] When the road surface is slightly bumpy, the off-road height adjustment module sends inflation or deflation signals to the left front air spring control valve, the right front air spring control valve, the left rear air spring control valve, and the right rear air spring control valve to control the height of the left front air spring, the right front air spring, the left rear air spring, and the right rear air spring to be in the neutral position.

[0251] When the road surface is severely bumpy, the off-road height adjustment module sends inflation or deflation signals to the left front air spring control valve, the right front air spring control valve, the left rear air spring control valve, and the right rear air spring control valve to control the height of the left front air spring, the right front air spring, the left rear air spring, and the right rear air spring to be in a high position.

Claims

1. A road class-based active suspension control system for a vehicle, characterized by, The application relates to a vehicle control system, which comprises a road type detection module, a steering type estimation module, a rollover state alarm module, a curve steering control module, a straight road obstacle avoidance control module, a longitudinal slope passing control module and a cross-country state control module. The road type detection module collects the maximum road curvature within 10 meters in front of the vehicle to determine the road type in front of the vehicle, collects the road support force on the left front suspension, the road support force on the right front suspension, the road support force on the left rear suspension, the road support force on the right rear suspension and the longitudinal acceleration of the vehicle when the vehicle is running on the road, and uses a longitudinal slope calculation formula to determine the road longitudinal slope at the current position of the vehicle. The steering type estimation module collects the steering wheel angular velocity, the vehicle body roll angular acceleration and the brake pedal force, and uses a steering type estimation formula to estimate the steering type of the vehicle. The rollover state alarm module monitors the wheel speed, the left front air suspension pressure, the right front air suspension pressure, the left rear air suspension pressure and the right rear air suspension pressure during the running of the vehicle, and uses a rollover state alarm formula to determine whether to send a rollover alarm signal. The curve steering control module is in communication connection with the steering type estimation module and the road type detection module, can obtain the steering type and the maximum road curvature within 10 meters in front of the vehicle, and uses a height change formula to control the average height of the left front air spring and the left rear air spring and the average height of the right front air spring and the right rear air spring. The straight road obstacle avoidance control module is in communication connection with the steering type estimation module and the road type detection module, can obtain the steering type and the maximum road curvature within 10 meters in front of the vehicle, and uses a damping coefficient change formula to control the average damping coefficient of the left front variable damping shock absorber and the left rear variable damping shock absorber and the average damping coefficient of the right front variable damping shock absorber and the right rear variable damping shock absorber. The longitudinal slope passing control module comprises a vehicle body longitudinal height adjusting module and a vehicle body longitudinal height dynamic feedback adjusting module, is in communication connection with the road type detection module, obtains the road longitudinal slope at the current position of the vehicle, uses a longitudinal downward steep slope height adjusting formula or a longitudinal upward steep slope height adjusting formula to control the average height of the left front air spring and the right front air spring and the average height of the left rear air spring and the right rear air spring, and adjusts the inflation speed or the deflation speed of the left front air spring electric control valve, the left rear air spring electric control valve, the right front air spring electric control valve and the right rear air spring electric control valve. The cross-country state control module comprises a road bumping degree judgment module and a cross-country height adjusting module, uses a road bumping degree judgment formula to judge the road bumping degree, and controls the height of the left front air spring, the height of the right front air spring, the height of the left rear air spring and the height of the right rear air spring to be in a low position state, a middle position state or a high position state through the cross-country height adjusting module. ​ 2. The road class based active suspension control system for a vehicle according to claim 1, wherein The road type detection module comprises a road curvature detector and a road longitudinal slope detector, the road curvature detector obtains the maximum road curvature within 10 meters in front of the vehicle, and the road longitudinal slope detector obtains the road longitudinal slope at the current position of the vehicle; The road curvature detector comprises a vehicle-mounted camera, which scans the maximum road curvature within 10 meters in front of the vehicle to determine the type of road in front of the vehicle within 10 meters; When |R1| > R 1,critical , the road type within 10 meters in front of the car is a curve. When |R1|≤R 1,critical , the road type within 10 meters in front of the car is a straight road; wherein R1 is in meters -1 R 1,critical is a road type standard value in meters -1 and R 1,critical > 0; R1 is positive when the maximum road curvature within 10 meters in front of the vehicle is located on a left turn road; R1 is negative when the maximum road curvature within 10 meters in front of the vehicle is located on a right turn road. The road longitudinal slope detector comprises a pressure sensor on the left front suspension, a pressure sensor on the right front suspension, a pressure sensor on the left rear suspension, a pressure sensor on the right rear suspension, and a vehicle longitudinal acceleration sensor; a pressure sensor on the left front suspension obtains a road support force f received by the left front suspension fl a pressure sensor on the right front suspension obtains a road support force f received by the right front suspension fr a pressure sensor on the left rear suspension obtains a road support force f received by the left rear suspension rl a pressure sensor on the right rear suspension obtains a road support force f received by the right rear suspension rr a vehicle longitudinal acceleration sensor obtains a longitudinal acceleration a of the vehicle when the vehicle is running on the road y a road longitudinal slope R2 of a current position of the vehicle is calculated according to a longitudinal slope calculation formula: wherein R2 is in units of radians, sgn() denotes the sign function, and f fl +f fr -f rl -f rr > 0, sgn(f fl +f fr -f rl -f rr ) = 1, the road longitudinal slope at the current position of the vehicle is downhill; when f fl +f fr -f rl -f rr = 0, sgn(f fl +f fr -f rl -f rr ) = 0, the road longitudinal slope at the current position of the vehicle is 0; when f fl +f fr -f rl -f rr < 0, sgn(f fl +f fr -f rl -f rr ) = -1, the road longitudinal slope at the current position of the vehicle is uphill. When |R2| > R 2,critical , the road longitudinal slope of the current position of the automobile is a longitudinal steep slope; When R2>R 2,critical , the road longitudinal slope of the current position of the automobile is a longitudinal downward steep slope; When R2< -R 2,critical , the road longitudinal slope of the current position of the automobile is a steep slope in the longitudinal direction. When |R2|≤R 2,critical , the road longitudinal slope of the current position of the automobile is a longitudinal gentle slope; In the formula, R 2,critical It is the standard value of the longitudinal slope of the road, R 2,critical The unit is radians, and R 2,critical >0; m represents the total mass of the car in kg, and g represents the acceleration due to gravity, taken as g = 9.8 m / s². 2 When the car accelerates, the longitudinal acceleration a y The longitudinal acceleration a is positive when the car decelerates. y It is negative.

3. The road class based active suspension control system for a vehicle according to claim 1, wherein The steering type estimation module can estimate the steering type of the vehicle according to a steering type estimation formula; The steering type estimation module comprises a vehicle basic information module, which stores the upper limit of the steering wheel angular velocity of the vehicle, the upper limit of the body roll angular velocity of the vehicle in a stable working condition, and the upper limit of the brake pedal force; The steering type estimation module includes a steering wheel angular velocity sensor, a vehicle body roll angular acceleration sensor, and a brake pedal force sensor, and estimates the steering type P by the steering type estimation formula S : In the formula, P S is a dimensionless value used to determine the type of vehicle steering; β1, β2 and β3 are weight factors, and appropriate values can be obtained through neural network training; v sw is the steering wheel angular velocity obtained by the steering wheel angular velocity sensor, with the unit of rad·s -1 , v up is the upper limit of the steering wheel angular velocity, with the unit of rad·s -1 , α v is the vehicle body roll angular acceleration obtained by the vehicle body roll angular acceleration sensor, with the unit of rad·s -2 , α up is the upper limit of the vehicle body roll angular acceleration for keeping the vehicle in a stable working condition, with the unit of rad·s -2 , F b is the brake pedal force obtained by the brake pedal force sensor, with the unit of N, F up is the upper limit of the brake pedal force, with the unit of N; The turning type P S The two situations correspond to two turning types respectively: When P S ≥ P critical , the turning type is a sharp turn. When P S <P critical is less than 0.5, the turning type is a slow turn. where P critical is the steering type standard value, which is a dimensionless value.

4. The road class based active suspension control system for a vehicle according to claim 1, wherein The rollover state alarm module comprises a sound prompter, a wheel speed sensor, a left front air suspension pressure sensor, a right front air suspension pressure sensor, a left rear air suspension pressure sensor, and a right rear air suspension pressure sensor; The wheel speed sensor monitors the wheel speed ω during the driving of the vehicle w When ω w <ω w,critical , the rollover state warning module does not issue a warning signal, wherein ω w,critical is a wheel speed standard value; When the wheel speed ω monitored by the wheel speed sensor w >ω w,critical is used to determine whether to issue an alarm signal using a rollover state alarm formula: Q max = max{Q fl , Q fr , Q rl , Q rr} F fl , F fr , F rl , F rr are the left front air suspension pressure, the right front air suspension pressure, the left rear air suspension pressure, the right rear air suspension pressure monitored by the left front air suspension pressure sensor, the right front air suspension pressure sensor, the left rear air suspension pressure sensor, the right rear air suspension pressure sensor respectively, and the unit is N, F f is the average of the left front air suspension pressure and the right front air suspension pressure, and the unit is N, F r is the average of the left rear air suspension pressure and the right rear air suspension pressure, and the unit is N, Q fl is the left front air suspension pressure offset rate, which is a dimensionless value, Q fr is the right front air suspension pressure offset rate, which is a dimensionless value, Q rl is the left rear air suspension pressure offset rate, which is a dimensionless value, W rr is the right rear air suspension pressure offset rate, which is a dimensionless value, Q max is the maximum value of the automobile suspension pressure offset rate, which is a dimensionless value; When Q max ≤ Q critical , the roll-over state alarm module does not send an alarm signal, wherein Q critical is a roll-over pressure offset rate standard value, which is a dimensionless value. When Q max >Q critical When the rollover state alarm module sends a rollover alarm signal, the sound prompter will prompt the driver to reduce the vehicle speed or drive off the current road.

5. The vehicle active suspension control system based on road class according to claim 1 or 2 or 3, characterized in that, The curve steering control module comprises a left front air spring electric control valve, a right front air spring electric control valve, a left rear air spring electric control valve, and a right rear air spring electric control valve; The curve steering control module can send an inflation or deflation signal to the left front air spring electric control valve, the right front air spring electric control valve, the left rear air spring electric control valve, and the right rear air spring electric control valve to change the average height of the left front air spring and the left rear air spring and the average height of the right front air spring and the right rear air spring; The curve steering control module is in communication connection with the steering type estimation module and the road type detection module, and can obtain the steering type PS and the maximum road curvature R1 within 10 meters in front of the vehicle; The curve steering control module further comprises a vehicle basic information module, which stores the standard body height of the vehicle; When the road type detection module judges that the road type in front of the car within 10 meters is a curve, and the steering type estimator judges that the steering type is slow turning, i.e. |R1|>P critical and P S <P critical , the steering working condition control module judges that the car is in a curve steering working condition, and controls the average height of the left front air spring and the left rear air spring, and the average height of the right front air spring and the right rear air spring through the following height change formula: Δ h = h l - h r where Δ h is the difference between the average height of the left front and left rear air springs and the average height of the right front and right rear air springs, in m, h l is the average height of the left front and left rear air springs, in m, h fl is the left front air spring height, in m, h rl is the left rear air spring height, in m, h r is the average height of the right front and right rear air springs, in m, h fr is the right front air spring height, in m, h rr is the right rear air spring height, in m, h v is the vehicle standard body height, in m; δ1 and δ2 are weight factors, and appropriate values can be obtained through neural network training; When the road within 10 meters in front of the vehicle is a left turn, i.e. R1>0, the average height of the left front air spring and the left rear air spring remains unchanged, the curve steering control module sends an inflation signal to the right front air spring electric control valve and the right rear air spring electric control valve to increase the average height of the right front air spring and the right rear air spring, and the difference between the average height of the left front air spring and the left rear air spring and the average height of the right front air spring and the right rear air spring is equal to the result value of the height change formula; When the road is right turn within 10 meters in front of the car, that is, R1<0, the average height of the right front air spring and the right rear air spring is unchanged, the bend steering control module sends the inflation signal to the left front air spring electric control valve and the left rear air spring electric control valve, so that the average height of the left front air spring and the left rear air spring is increased, and the difference between the average height of the left front air spring and the left rear air spring and the average height of the right front air spring and the right rear air spring is equal to the result value of the height change formula.

6. The vehicle active suspension control system based on road class according to claim 1 or 2 or 3, characterized in that, The straight road obstacle avoidance control module comprises a left front variable damping shock absorber electric control valve, a right front variable damping shock absorber electric control valve, a left rear variable damping shock absorber electric control valve, a right rear variable damping shock absorber electric control valve and a steering wheel angle sensor; The straight road obstacle avoidance control module can send signals to the left front variable damping shock absorber electric control valve, the right front variable damping shock absorber electric control valve, the left rear variable damping shock absorber electric control valve and the right rear variable damping shock absorber electric control valve, so as to change the average damping coefficient of the left front variable damping shock absorber and the left rear variable damping shock absorber, and the average damping coefficient of the right front variable damping shock absorber and the right rear variable damping shock absorber; and the steering wheel angle sensor can collect the size and direction of the steering wheel angle. The bend steering control module is in communication connection with the steering type estimation module and the road type detection module, and obtains the steering type Ps and the maximum road curvature R1 within 10 meters in front of the car; The bend steering control module further comprises a vehicle basic information module, and the information stored in the vehicle basic information module includes a standard vehicle body height of the car; When the road type detection module determines that the road type in front of the vehicle within 10 meters is a straight road, and the steering type estimator determines that the steering type is a sharp turn, i.e., |R1| < R 1,critical and P S > P critical , the average damping coefficients of the left front and left rear variable damping shock absorbers and the average damping coefficients of the right front and right rear variable damping shock absorbers are controlled by the following damping coefficient change formula: Δ C = Δ C,l - Δ C,r where Δ C is the difference between the average damping coefficient of the left front and left rear variable damping shock absorbers and the average damping coefficient of the right front and right rear variable damping shock absorbers in N·(m·s -1 ) -1 , Δ C,l is the average damping coefficient of the left front and left rear variable damping shock absorbers in N·(m·s -1 ) -1 , Δ C,fl is the damping coefficient of the left front variable damping shock absorber in N·(m·s -1 ) -1 , Δ C,rl is the damping coefficient of the left rear variable damping shock absorber in N·(m·s -1 ) -1 , Δ C,r is the average damping coefficient of the right front and right rear variable damping shock absorbers in N·(m·s -1 ) -1 , Δ C,fr is the damping coefficient of the right front variable damping shock absorber in N·(m·s -1 ) -1 , Δ C,rr is the damping coefficient of the right rear variable damping shock absorber in N·(m·s -1 ) -1 ; θ sw is the steering wheel rotation angle obtained by the steering wheel rotation angle sensor, in radian, θ sw > 0, sgn(θ sw ) = 1 when the steering wheel rotates counterclockwise, θ sw < 0, sgn(θ sw ) = -1 when the steering wheel rotates clockwise, and θ sw = 0, sgn(θ sw ) = 0 when the steering wheel does not rotate, m is the total mass of the vehicle, in kg, h v is the standard body height of the vehicle, in m; When the steering wheel angle is counterclockwise, the car is in the straight road obstacle avoidance left turn working condition, the average damping coefficient of the left front variable damping shock absorber and the left rear variable damping shock absorber is unchanged, the straight road obstacle avoidance control module sends signals to the right front variable damping shock absorber electric control valve and the right rear variable damping shock absorber electric control valve, so that the average damping coefficient of the right front variable damping shock absorber and the right rear variable damping shock absorber is reduced, and the difference between the average damping coefficient of the left front variable damping shock absorber and the left rear variable damping shock absorber and the average damping coefficient of the right front variable damping shock absorber and the right rear variable damping shock absorber is equal to the result value of the damping coefficient change formula. When the steering wheel angle is clockwise, the car is in the straight road obstacle avoidance right turn working condition, the straight road obstacle avoidance control module sends signals to the left front variable damping shock absorber electric control valve and the left rear variable damping shock absorber electric control valve, so that the average damping coefficient of the left front variable damping shock absorber and the left rear variable damping shock absorber is reduced, the average damping coefficient of the right front variable damping shock absorber and the right rear variable damping shock absorber is unchanged, and the difference between the average damping coefficient of the left front variable damping shock absorber and the left rear variable damping shock absorber and the average damping coefficient of the right front variable damping shock absorber and the right rear variable damping shock absorber is equal to the result value of the damping coefficient change formula.

7. The road class based active suspension control system for a vehicle according to claim 1 or 2, wherein The longitudinal slope passing control module comprises a vehicle body longitudinal height adjusting module and a vehicle body longitudinal height dynamic feedback adjusting module. The vehicle body longitudinal height adjustment module comprises a left front air spring electric control valve, a left front air spring height sensor, a right front air spring electric control valve, a right front air spring height sensor, a left rear air spring electric control valve, a left rear air spring height sensor, a right rear air spring electric control valve and a right rear air spring height sensor. The vehicle body longitudinal height adjustment module can send an inflation signal or a deflation signal to the left front air spring electric control valve, the right front air spring electric control valve, the left rear air spring electric control valve and the right rear air spring electric control valve, so as to change the average height of the left front air spring and the right front air spring and the average height of the left rear air spring and the right rear air spring. The vehicle body longitudinal height adjustment module can collect height signals of the left front air spring height sensor, the right front air spring height sensor, the left rear air spring height sensor and the right rear air spring height sensor. The vehicle body longitudinal height adjustment module is in communication connection with the road type detection module, and can obtain the road longitudinal slope at the current position of the automobile. The vehicle body longitudinal height adjustment module further comprises a vehicle basic information module, and information stored in the vehicle basic information module includes an automobile wheelbase, an air spring maximum extension amount and an air spring maximum compression amount. The vehicle body longitudinal height dynamic feedback adjustment module can send a rapid inflation signal or a rapid deflation signal to the left front air spring electric control valve, the right front air spring electric control valve, the left rear air spring electric control valve and the right rear air spring electric control valve, so as to dynamically adjust the inflation speed or the deflation speed of the left front air spring electric control valve, the right front air spring electric control valve, the left rear air spring electric control valve and the right rear air spring electric control valve. When the road longitudinal slope |R2| < R 2,critical When the road longitudinal slope at the current position of the automobile is longitudinal gentle slope, the longitudinal slope control module and the longitudinal dynamic feedback adjustment module do not work, and do not control the difference between the average height of the left front air spring and the right front air spring and the average height of the left rear air spring and the right rear air spring. When the road longitudinal slope R2>R 2,critical When the road longitudinal slope R2>R at the current position of the automobile is a longitudinal steep downward slope, the vehicle body longitudinal height adjustment module sends an inflation signal to the left front air spring electric control valve and the right front air spring electric control valve to increase the average height of the left front air spring and the right front air spring, sends a deflation signal to the left rear air spring electric control valve and the right rear air spring electric control valve to decrease the average height of the left rear air spring and the right rear air spring, and controls the difference between the average height of the left front air spring and the right front air spring and the average height of the left rear air spring and the right rear air spring through a longitudinal steep downward slope height adjustment formula. The longitudinal steep downward slope height adjustment formula is as follows: When the expected front and rear air spring height difference is less than or equal to the sum of the air spring maximum extension amount and the air spring maximum compression amount, the difference between the average height of the left front air spring and the right front air spring and the average height of the left rear air spring and the right rear air spring is equal to the expected front and rear air spring height difference. When Δ h,goal ≤ Δ l,emax + Δ l,cmax , then Δ h = Δ h,goal ; where Δ h,goal = l x sin(R2), Δ h = h f - h r , where Δ h,goal is the desired front-rear air spring height difference in meters, Δ h,goal > 0, l is the wheelbase of the vehicle in meters, and R2 is the longitudinal slope of the road at the current position of the vehicle in radians. Δ l,emax is the maximum extension of the air spring, in m, Δ l,emax > 0, Δ l,cmax is the maximum compression of the air spring, in m, Δ l,cmax > 0, Δ h is the difference between the average height of the left and right front air springs and the average height of the left and right rear air springs, in m, h f is the average height of the left and right front air springs, in m, h fl is the left front air spring height collected by the left front air spring height sensor, in m, h fr is the right front air spring height collected by the right front air spring height sensor, in m, h r is the average height of the left and right rear air springs, in m, h rl is the left rear air spring height collected by the left rear air spring height sensor, in m, h rr is the right rear air spring height collected by the right rear air spring height sensor, in m; when Δ h,goal ≤ Δ l,emax + Δ l,cmax and the vehicle body longitudinal height dynamic feedback adjustment module sends the left front air spring electric control valve and the right front air spring electric control valve adjustment signals of rapid inflation. when Δ h,goal ≤ Δ l,emax + Δ l,cmax and the vehicle body longitudinal height dynamic feedback adjustment module sends an adjustment signal of slow inflation to the left front air spring electric control valve and the right front air spring electric control valve. When the expected front and rear air spring height difference is greater than the sum of the air spring maximum extension amount and the air spring maximum compression amount, the difference between the average height of the left front air spring and the right front air spring and the average height of the left rear air spring and the right rear air spring is equal to the sum of the air spring maximum extension amount and the air spring maximum compression amount. When Δ h,goal > Δ l,emax + Δ l,cmax , Δ h = Δ l,emax + Δ l,cmax ; When Δ h,goal > Δ l,emax + Δ l,cmax , the vehicle body longitudinal height dynamic feedback adjustment module sends the left front air spring electric control valve and the right front air spring electric control valve adjustment signals of rapid inflation. When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal slope R2 of the current position of the automobile is <-R 2,critical When the road longitudinal The longitudinal steep upward slope height adjustment formula is as follows: When the expected front and rear air spring height difference is greater than or equal to the opposite of the sum of the air spring maximum extension amount and the maximum compression amount, the difference between the average height of the left front air spring and the right front air spring and the average height of the left rear air spring and the right rear air spring is equal to the expected front and rear air spring height difference. When Δ h,goal ≥ -(Δ l,emax + Δ l,cmax ), set Δ h = Δ h,goal ; where Δ h,goal is the desired front, rear air spring height difference, Δ h,goal <0; when Δ h,goal ≥ -(Δ l,emax + Δ l,cmax ) and the vehicle body longitudinal height dynamic feedback adjustment module sends an adjustment signal of rapid inflation to the left rear air spring electric control valve and the right rear air spring electric control valve; when Δ h,goal ≥ -(Δ l,emax + Δ l,cmax ) and the vehicle body longitudinal height dynamic feedback adjustment module sends an adjustment signal of slow inflation to the left rear air spring electric control valve and the right rear air spring electric control valve; When the difference between the front and rear air spring height is expected to be less than the opposite of the sum of the maximum extension and the maximum compression of the air spring, the average height of the left and right front air springs is made equal to the average height of the left and right rear air springs, and the difference between the average height of the left and right front air springs and the average height of the left and right rear air springs is equal to the opposite of the sum of the maximum extension and the maximum compression of the air spring: When Δ h,goal <-(Δ l,emax +Δ l,cmax ), make Δ h =-(Δ l,emax +Δ l,cmax ) ; When Δ h,goal <-(Δ l,emax +Δ l,cmax ), the vehicle body longitudinal height dynamic feedback adjustment module sends an adjustment signal of rapid inflation to the left rear air spring electric control valve and the right rear air spring electric control valve.

8. The road class based active suspension control system for a vehicle as claimed in claim 1 wherein, The off-road state control module includes a road bump degree judgment module and an off-road height adjustment module; The road bump degree judgment module includes a left front air spring height sensor, a right front air spring height sensor, a left rear air spring height sensor, and a right rear air spring height sensor; The road bump degree judgment module can determine the road bump degree according to the left front air spring height collected by the left front air spring height sensor, the right front air spring height collected by the right front air spring height sensor, the left rear air spring height collected by the left rear air spring height sensor, and the right rear air spring height collected by the right rear air spring height sensor; The off-road height adjustment module includes a left front air spring electric control valve, a right front air spring electric control valve, a left rear air spring electric control valve, and a right rear air spring electric control valve; The off-road height adjustment module also includes a vehicle basic information module, which stores information such as the wheelbase of the vehicle; The off-road height adjustment module can send an inflation or deflation signal to the left front air spring electric control valve, the right front air spring electric control valve, the left rear air spring electric control valve, and the right rear air spring electric control valve, thereby controlling the height of the left front air spring, the height of the right front air spring, the height of the left rear air spring, and the height of the right rear air spring to be in a low position, a middle position, or a high position; The road bump degree judgment module determines the road bump degree according to the road bump degree judgment formula: wherein h fl is the left front air spring height collected by the left front air spring height sensor, in m, h fr is the right front air spring height collected by the right front air spring height sensor, in m, h f is the average of the left front air spring height and the right front air spring height, in m, h rl is the left rear air spring height collected by the left rear air spring height sensor, in m, h rr is the right rear air spring height collected by the right rear air spring height sensor, in m, h r is the average of the left rear air spring height and the right rear air spring height, in m, P fl is the left front air spring height variation degree, a dimensionless value, P fr is the right front air spring height variation degree, a dimensionless value, P rl is the left rear air spring height variation degree, a dimensionless value, P rr is the right rear air spring height variation degree, a dimensionless value, P is the overall vehicle air spring height variation degree, a dimensionless value, l2 is the wheelbase of the vehicle, in m. γ1, γ2, γ3, γ4 are weight factors, and appropriate values can be obtained through neural network training; When P < P low The road roughness degree is gentle. When P low <P<P high is less than 0.5, the road roughness is a slightly convex road surface. When P > P high , the road bumping degree is a serious convex road surface. P low is a first standard value of the air spring height variation degree, which is a dimensionless value, P high is a second standard value of the air spring height variation degree, which is a dimensionless value; When the road bump degree is gentle, the off-road height adjustment module sends an inflation or deflation signal to the left front air spring electric control valve, the right front air spring electric control valve, the left rear air spring electric control valve, and the right rear air spring electric control valve, thereby controlling the height of the left front air spring, the height of the right front air spring, the height of the left rear air spring, and the height of the right rear air spring to be in a low position; When the road bump degree is a slightly convex road surface, the off-road height adjustment module sends an inflation or deflation signal to the left front air spring electric control valve, the right front air spring electric control valve, the left rear air spring electric control valve, and the right rear air spring electric control valve, thereby controlling the height of the left front air spring, the height of the right front air spring, the height of the left rear air spring, and the height of the right rear air spring to be in a middle position; When the road bumping degree is a serious convex road surface, the off-road height adjustment module sends an inflation or deflation signal to the left front air spring electric control valve, the right front air spring electric control valve, the left rear air spring electric control valve and the right rear air spring electric control valve, and controls the height of the left front air spring, the height of the right front air spring, the height of the left rear air spring and the height of the right rear air spring to be in a high position state.

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