Research On The Control Strategy Of Electronically Controlled Air Suspension

The suspension system is an important part of the car which plays a vital role on its ride comfort, handling and stability. In the same vehicle load, air spring vibration frequency lower compared with ordinary spring. It can effectively improve the car’s ride comfort. Air suspension is a new type vehicle suspension which has great market prospects and broad space of development.This paper used a commercial air spring suspension as the study object. the structure and principle of the air spring was analyzed. The stiffness characteristics of the air spring were simulated by MATLAB software. A variety of non-linear relationship between the initial pressure of the air force of the spring and the spring-shaped was fitted. Taking this nonlinear model into the air suspension, a non-linear model of air spring suspension was obtained. As the basis for the establishment of an air spring suspension, linear and nonlinear models active control model were established, respectively.For linear air suspension model established linear quadratic optimal controller. For nonlinear air suspension model established PID controller, suboptimal controller, fuzzy control and fuzzy PID controllers. Through four control methods theory and simulation results show that the nonlinear controller established air suspension ride and road-friendly is a certain improvement. Using combined fuzzy PID control nonlinear air suspension for ride comfort of the three indexes of ride comfort was improved significantly and the overall optimal performance is best.