Dynamic Characteristics And Control Of Air Suspension With A Additional Air Chamber

The suspension plays a very important role in the vehicle's ride comfort and operation stability.With the development of science and technology,the traditional passive suspension,has been unable to fully meet the needs of people for high-performance cars.Although the active suspension in the application process,can achieve good performance requirements,it also need more equipment and power source support.The system is more complex.Air spring in the the design of the curve is very diverse.It can be flexible to charge and discharge,making the air spring stiffness changes more convenient.The vehicle with air suspension can obviously improve the dynamic load of the tire and the dynamic travel of the suspension.The air suspension with additional air chamber has larger air capacity,and the range of stiffness adjustment is further increased.In the past,most of the air suspension papers,using 2 degrees of freedom 1/4 car model,the 1/2 model of 4 degrees of freedom for analysis.1/4 car,1/2 car although has the basic vibration performance of vehicle driving,the pitch,roll,suspension for driving the dynamic deflection and tire dynamic load is not basic,good research.Therefore,it is necessary to study the seven degree of freedom of the vehicle with additional air suspension.In this paper,the performance and present situation of air suspension with additional air chamber are studied.Through the study of the working principle of air spring,with aerodynamics,thermodynamics,nonlinear differential equations with air spring is established.Using the method of small deviation linearization,fit out the and the relationship between dynamic stiffness of air spring and orifice opening.According to the differential equation of seven degree of freedom suspension and the input differential equation of the four wheel stochastic road surface,the simulation model is established.Through the control mechanism of PID and fuzzy PID,based on the relationship between the opening and the dynamic stiffness,the design of the seven degrees of freedom vehicle PID and fuzzy PID controller is established with air suspension,fuzzy PID simulation model PID.Studythe effect of the two control methods,and find out which control can improve the performance of the vehicle.The results show that the PID and fuzzy PID control to acceleration,roll angle acceleration,pitch angle acceleration,suspension vertical suspension deflection and tire dynamic load of the maximum value,minimum value and variance have been significantly weakened,which lead to better ride comfort.And the control method of fuzzy PID is better than the single PID control mode.