Performance of Limited Bandwidth Active Suspension Based on a Half Car Model

In this paper, the performance of hydro-pneumatic limited bandwidth active suspension system is studied theoretically using a half car model. The bounce and pitch motions for the sprung mass and two vertical degrees of freedom for the unsprung mass's are considered (to permit for good suspension design). The linear optimal control theory is used to derive the full state feedback and feedforward control laws taking into account the correlation between the front and rear wheel excitation. The results are generated when the vehicle running on a statistically random road using a 6 Hz bandwidth analogue controller. A comparison between the conventional passive, limited bandwidth active suspensions with and without wheelbase correlation are presented and discussed. The results showed that there is a worthwhile improvement for the proposed active system over the passive, while incorporating wheelbase correlation added more benefits for the rear axle dynamics and pitch motion.