Radiation modal expansion: Application to active structural acoustic control

Abstract

This paper demonstrates active structural acoustic control using multiple input/output adaptive sensoriactuators combined with radiation filters and a feedback control paradigm. A new method of reduced order modeling/design of radiation filters termed radiation modal expansion (RME) is presented. For the experiments detailed in this paper, the RME technique reduced the modeling of the radiation matrix from 400 transfer functions to 6 transfer functions (multiplied by a constant transformation matrix). Experimental results demonstrate reductions of radiated sound power on the order of 5 dB over the bandwidth of 0-800 Hz.

Active control of structures and sound radiation modes and its application in vehicles

“…Wang and Lai 4 used boundary element method to study the sound radiation efficiency of the circular plate under mechanical excitation and conducted experiments to verify the researched result, but he failed to point out the relationship between structural modes and sound radiation modes. Gibbs et al 5 studied the relationship between structural modes and sound radiation modes, and found noises in the low frequency could be effectively reduced through controlling sound radiation modes. However, his research was not verified by experiments.…”

A rapid prototyping system for broadband multichannel active noise and vibration control

“…For a feedforward control system the average noise reduction was 7 dB; the reduction on the error sensors was 15.5 dB. If higher noise reductions are to be obtained, particularly with feedforward control, then probably the cost function of the control algorithm should be modified in order to include a relationship between the sensor signals and the acoustic radiation from the panel , such as with a radiation mode based technique [12].…”

“…where an auxiliary disturbance signal d (n)is defined as 12) and where, according to Eq. (3.7), the delayed preconditioned control output y (n) is defined by…”

“…Define the quadratic cost criteria as 12) with the property of the expectation operator that E(x + y) = E(x) + E(y). Minimizing Eq.…”

“…A control system is used to reduce the sound transmitted through the panel (See Refs. [10][11][12]). Possible applications can be found in buildings, trains, cars, aircrafts, etc.…”