Investigation of the effect of active suspension system using air spring and air spring rigidity parameters on system performance in passenger vehicles

Suspension systems are used in order to insulate the vibrations which are occurred during the travel on the roads and/or because of the different parts of the car, furthermore to improve the dynamic comfort. While the suspension systems are effecting the dynamic comfort, they also effect the stability of the car and these effects are working oppositely to each other. Air spring is produced by locating a rubber body on the amortization element rather than locating a spiral spring. The difference of the air springs from the mechanical springs is that, by the changing of the pressure inside, the strength of the spring changes as well. Thus, nowadays air springs are more preferred because while they are improving the driving comfort, they have also ability to control actively and semi-actively in order not to reduce the stability. Air springs are used generally in trains, heavy goods vehicles and passenger cars. In this study, passive and active suspension systems that are used in passenger vehicles and their effects on the system performance has been examined. By experiments, the strength of the air spring has been obtained/calculated. This air spring strength, which has been obtained by the experiments, is used to create quarter, semi and full vehicle models by using MATLAB and sub-system of MATLAB: Simulink. Different start signals are applied to these models to analyze the outputs of vertical chassis translocations and frequency responses. In the study LQR and PID control methods have been used as active suspension systems controller.