Design of a smart panel with multiple decentralised units for the control of sound radiation/transmission

This paper summarizes the experimental work carried out to develop a prototype smart panel with sixteen decentralized vibration control units for the reduction of sound radiation. The system studied consists of a thin aluminum panel of dimensions l(x) x l(y) = 414 x 314 mm and thickness 1 mm with an embedded array of 4 x 4 square piezoceramic actuators. The sensing system equally consists of an array of 4 x 4 accelerometers that are arranged in such a way as to match the centre positions of the sixteen piezoceramic patches. Each of the sixteen sensor actuator pairs is set to implement decentralized velocity feedback control. In this paper the design of the sixteen modular sensor-controller-actuator systems is discussed in detail. The open loop sensor-actuator measured frequency response function is first analysed and contrasted with that derived from simulations, in a frequency range up to 50 kHz. This analysis is mainly focussed on the higher frequency effects due to the size of the piezoelectric actuator and generated by the dynamics of the accelerometer sensor. The stability of one or all sixteen control units are assessed experimentally using the Nyquist criterion. The reduction of sound radiation and panel vibration is then assessed with reference to a primary force excitation acting on the panel.