ADVANCED TIME-DOMAIN WAVE-NUMBER SENSING FOR STRUCTURAL ACOUSTIC SYSTEMS .2. ACTIVE RADIATION CONTROL OF A SIMPLY SUPPORTED BEAM

A real time structural acoustic sensor and associated signal processin g is developed and applied to the active control of sound radiated by a simply supported beam. The sensor consists of multiple accelerometer s mounted on the structure. An array of FIR filters processes the meas ured structural information to provide an estimate of the structural w ave-number component coupled to acoustic radiation in a prescribed dir ection. This time domain signal is used as the error information in a feedforward adaptive control approach. The single channel filtered-X L MS algorithm is implemented here. Computer simulations in the discrete time domain demonstrate the ability of the sensor to replace the use of error microphones in the far field. The described sensor represents a significant alternative to the use of distributive structural senso rs (for example piezoelectric material) by providing accurate radiatio n information over a broadband frequency range.