| China is a big country in automobile ownership and manufacturing,and the development of the automotive industry is related to the lifeline of China’s national economy.As a common industrial product with a high level of integration in life,no matter what the development of the car,its basic driving function will not change,vehicle driving smoothness and safety is the basic evaluation index to evaluate the performance of the car,so it is of great significance to study the semi-active suspension system that can improve the basic performance of the car.This thesis takes magnetorheological semi-active suspension as the work object,and the primary contents are as follows:Firstly,the working principle and output characteristics of magnetorheological damper are analyzed,and the common description models of magnetorheological damper are analyzed.Based on the characteristics that the control input of the controlled object is the damping force,the reverse model of magnetorheological damper is established by deriving the forward model of the magnetorheological damper,so as to realize the transformation of the input-output relationship of the system,and finally simulate and analyze the established magnetorheologic al damper forward and reverse model.Secondly,the vehicle semi-active suspension model and random road surface,impact road surface and sinusoidal road surface model are established,and finally the amplitude-frequency characteristic curve of the passive suspension system is obtained by sinusoidal excitation method,and the influence of the inherent parameter value of passive suspension on the vibration characteristics of the vehicle is analyzed.Then,the optimization effect of canopy,basement and acceleration damping control algorithms commonly used in suspension system control on suspension vibration characteristics is analyzed,and the optimization characteristics of canopy control and shed control on vehicle driving smoothness and safety are analyzed,and a fuzzy hybrid canopy and basement control algorithm is established by combining canopy control and shed control through fuzzy control.Then,the suspension vibration characteristics of canopy control and acceleration damping control are investigated,and the ceiling acceleration damping control algorithm for vehicle driving smoothness is established by combining the optimization characteristics of these two controls on vehicle driving smoothness in different frequency domains.Finally,according to the complex working conditions and interference factors during vehicle driving,the semi-active suspension sliding mode control algorithm is studied,considering the optimization effect of canopy acceleration damping control on vehicle driving smoothness,on this basis,a sliding mode control algorithm based on the ceiling acceleration damping control reference model is established,and the sliding mode control can better optimize the driving smoothness of vehicles on impact roads and medium and low frequency roads by simulating under impact roads and road surfaces in different frequency domains. |
