Reduction of structure-borne noise in automobiles by multivariable feedback

The vibration transmitted through the suspension of a car is the dominant source of structurally-generated interior noise at low frequencies. With the addition of actuators between the suspension attachment points and the car frame, we propose the design of a feedback controller for an active control of the vibrations to reduce cabin noise. A model-based controller design requires the identification of a transfer function model of the suspension, the frame, and the cabin acoustics. Here we deal with model identification of a suspension testbed. Uncertainty bounds for the flexible mode parameters of the model are estimated from experimental input-output data for a future robust mu-synthesis controller design. A preliminary controller is designed and tested by simulation for the identified nominal model. Inputs to the controllers are given by force and acceleration sensors measuring the vibration at different points on the suspension.