An adaptive controller for multivariable active noise control

Abstract The control of vibration through the mounts of rotating machines can be achieved by actively generating cancelling forces from shakers located close to the mounts. The cancelling waveforms cannot simply be an antiphase copy of the original waveform as each shaker affects the vibration at mounts other than the one at which it is cancelling. This paper describes an approach to this multivariable control problem which measures all shaker to sensor transfer functions to give a shaker transfer function matrix, M (f) . The shakers are driven by voltages V (f) given by V (f) = −M −1 (f) U (f) where U (f) is the vector of accelerations at the mounts. The controller then repeats the algorithm, this time operating on the residual accelerations at the sensors. The system is therefore adaptive and can cope with slowly changing noise spectra. Cancellations of better than −25 dB have been achieved.