A two-time-scale analysis of active suspension control of a 2D/4DOF half-car model

The LQ-optimal control of front and rear suspensions is considered for a half-car, 2D vehicle model including unsprung masses. The paper clarifies some issues related to system controllability, and extends previous analytical results to the case of half-car models with unsprung mass, wheel-hop dynamics. This is done in a form of composite controls which exploit the two-time-scale system characteristics. The analytical results are illustrated with a number of examples which show the extent of the validity and limitations of the approach.