Semi-active control of the Macpherson suspension system: hardware-in-the-loop simulations

A modified skyhook control for the semi-active Macpherson suspension system is considered. A new quarter-car model, which incorporates the rotational motion of the unsprung mass, is introduced. A feedback control law in the form of a modified skyhook control is derived. Two filters to estimate the absolute velocity of the sprung mass and the relative velocity of the rattle space are designed. By including the actual semi-active damper in the loop of computer simulation, the nonlinearity, time-delay, and unmodeled dynamics of the continuously variable damper have been incorporated. The control performances of the semi-active system and a passive one were compared.