Reduction of broadband noise in vehicles by means of active feedforward control

Broadband noise in a vehicle’s interior is an important issue because of its negative impact on the passengers’ comfort and wellbeing. The perception of this broadband noise can increase due to the use of new, less noisy drive concepts and the accompanying loss of masking noise components. This contribution focuses on the reduction of the transmission of external broadband disturbances through lightweight panel structures (e.g. a car’s roof liner or an aircraft sidewall panel) by means of active feedforward control. The aim of this work is to demonstrate the potential and to motivate the implementation of active feedforward (instead of feedback) control for the reduction of broadband noise in vehicles. A new method is introduced to quantify the causality of an active feedforward control system configuration. Simulation results show a similar causality of active single and double panel systems, yet a significantly increased control performance of more than 10 dB in the reduction of the sum of the mean-squared error signals of the active double panel system. The main conclusion of this work is that the transmission of external broadband disturbance sources through double-walled vehicle or aircraft structures can be significantly reduced by the application of active feedforward control.