Broad band active vibration isolation of automobile engine using linear and nonlinear feedback control is considered. The objective is to reduce the forces transmitted to the chassis and body, and, thus, reducing vibrations and structure borne noise inside the vehicle compartment when the engine is subjected to different excitations. Moreover, the ability of the original passive suspension system to deal with high load transient excitation, eg due to a dropped clutch operation, has to be preserved. Engine excitations corresponding to idle and driving engine operating conditions as well as internal and external transient excitations have been investigated.

Solutions based on classical control and LQG (Linear Quadratic Gaussian) control methodologies have, to some extent, been treated. However, it turns out that the desired loop gain requires a control design method more suitable for shaping the loop gain and, at the same time, obtaining closed-loop stability. Using H2 control theory and Gain Scheduling, a MIMO (multi-input multi-output) control algorithm dealing with the above mentioned excitations when taking system nonlinearities into account, is developed.