Comparative Study of Conventional PD and Fuzzy PD Controllers for a Non-linear Active Suspension System

This paper presents a comparative study of conventional PD and Fuzzy PD (FPD) Controllers for a nonlinear active suspension system for quarter car. The control purpose is to upgrade ride quality of quarter car by reducing the root mean square of vertical acceleration (RMSVA) while keeping all hard constraints like suspension movement, dynamic and static load on tyre and actuator saturation within limits. The gains of PD and FPD controllers are tuned by Genetic Algorithms (GA) optimization technique for random road profiles by minimizing a cost function consist of integral of time-weighted absolute error and RMSVA and a comparative study is carried out. Further, controllers tuned with random road surface are tested on bump road profile for various amplitude. It has been noted that FPD controller out performed conventional PD controller and provided superior ride comfort.