Stiffened panel sound radiation attenuation using acceleration feedback and internal model control

Aircraft stiffened panel is used as a control object and active structural acoustic control system is set up to mimic real aircraft cabin noise control problem, since sound isolation performance of the panel is poor at low frequencies. According to Rayleigh integral theory, there is a close relationship between the panel´s volume acceleration signal and far field sound pressure, which indicates that active control the volume acceleration is an effective control solution to improve the panel´s sound isolation performance. Thus the relationship between the volume acceleration and far field sound pressure is deduced analytically. In the active control experiment, three acceleration sensors are used to provide effective structural sensing, without the need to use traditional microphone sensors. Piezoelectric patches are used as actuators. This arrangement makes the whole system more compact and practical than before. An adaptive internal model feedback control is used which does not require the state space representation of the system. Control experiments show that at some frequency the noise reduction in the cabin could be lowered more than 7 dB.