Acoustics Laboratory

An adaptive feedback system for the active control of sound and vibration is investigated. The controller combines adaptation for minimum variance of the error, to achieve optimal H₂ performance for every disturbance, and H_∞ robust stability measures, to account for uncertainties in the plant. An Internal Model Control configuration is used, with a fixed FIR filter for the plant model, and an adaptive FIR filter for the controller. The adaptation is performed using the Filtered-x LMS algorithm, which is modified so that it converges to a robust controller. The considerations for using this design in active control are discussed, and implementation results on active noise reducing headphones are presented.