Abstract:

Actuator performance is a critical part of active noise and acoustic control. The loudspeakers that are normally used as actuators in many active noise and acoustic control applications add significantly to the dynamics of the control loop and are detrimental to the controller's performance. By compensating a loudspeaker with a technique similar to motional feedback, the loudspeaker performance is enhanced in applications such as control of acoustic enclosures. In this work, a method to easily and reliably compensate a loudspeaker in order to approximate constant volume velocity behavior over the piston-mode frequency range is presented and demonstrated. This reduces the influence of the environment upon the actuator, reduces low-frequency distortion of the speaker, and minimizes magnitude and phase shifts of the intended control signal. Numerical simulations and experimental results of the proposed methods are included. [Work supported in part by the Lord Corporation and the National Science Foundation under Grant No. CMS 95-01470.]