Composite active suspension for automotive vehicles

This article describes the development of a composite controller for an active suspension system. This consists of two controllers operating together over different frequency ranges. The first of these is required to cancel out the low-frequency dynamic loads experienced during cornering and braking in order to maintain a level vehicle platform. The second is required to isolate the car body from vibrations caused by the high-frequency road profile. Furthermore, the vibration controller is based on a fully adaptive control algorithm. This enables the suspension to auto-tune to different vehicle payloads, tyre stiffnesses and other parameter variations experienced during progressive wear, and to adapt to the varying road frequency spectrum. Simulations were performed on a quarter car (one wheel) suspension model and the results obtained demonstrated the potential benefits of composite and adaptive control in active suspension design.