Active Structural and Acoustic Control of Structure-Borne Road Noise in a Passenger Car

Abstract

Within the Brite-Euram Project “Anrava” several active control systems have been evaluated in order to reduce the road noise generated inside the cabin of a mid size station wagon during driving condition on different road surfaces. Different control strategies (feedforward with local and global control, pure feedback) and different approaches (active structural acoustic control and active noise control) have been tested on the car in laboratory conditions and the control performances have been evaluated. The final control strategies that have been selected based on the results of this study, are based on an adaptive feedforward control algorithm: six accelerameters provide the reference signals and 4 microphones placed inside the cabin give the error feedbacks. Two control configurations, each using a different kind of control source, have been retained : a structural acoustic control system which works with 6 inertial shakers positioned at the main vibration transmission paths of the car suspension, an anti-noise system with 4 loudspeakers inside the cabin. The paper describes the approaches utilised to design the different control systems and presents the results obtained during laboratory and road tests, comparing them with the performances predicted by numerical simulations.