Abstract:

Performance comparisons of active structural-acoustic control system designs with respect to controller power requirements are important for practical implementation. In this work, a broadband measure of controller energy usage per unit of input disturbance energy is developed. This metric is the H[inf 2] norm of the system transfer matrix from the disturbance signals to the control actuator signals. Comparisons of acoustic performance are made for three output feedback controllers, each designed to reduce one of the following variables: (1) sound power radiation; (2) structural modal velocity; and (3) structural velocity at twelve discrete points. All three controllers were designed such that their controller power requirements were equivalent. An array of five, exogenous, point-force disturbances were used to drive a plate model, and each control system utilized the same three colocated point-velocity sensor and point-force actuator pairs. Analytical results demonstrate that the cost functional based upon sound power places a greater emphasis in controlling the low-frequency bandwidth. This controller provides 2.5-dB greater sound reduction than design #2 in the third octave band including the first radiation mode and 2.7-dB greater reduction than #3 in the same band. [Work supported by NSF Career Program CMS-9501470.]