A new adaptive sky-hook control of vehicle semi-active suspensions

This paper proposes a new adaptive sky-hook control law for vehicle semi-active suspensions. Vehicle suspensions are disturbance-affected dynamic systems. In semi-active suspensions, damping coefficients are controlled so as to make the actual damper force as close to the desired damper force as possible at any time instance. The proposed control law consists of a 'new adaptive' sky-hook damping algorithm and a road detection algorithm (RDA). This approach leads to the sprung mass and unsprung mass velocity feedback control law with time varying gains. The gains are tuned by the RDA. To evaluate the performance enhancement brought about by the proposed control law, the performance of a semi-active suspension with the proposed control law is compared with that of the sky-hook controlled semi-active suspension and with a passive suspension. The controllers are implemented experimentally on a quarter-car test rig and a semi-active damper with 19 damping rates has been used to generate the desired semi-active force. The performance of the proposed control law is shown to be superior to that of the sky-hook control.