Research On Active Structures Acoustic Control Based On Control Strategy Of Acoustic Radiation Modes

The theory of acoustic radiation modes is a effective method to analyze the behavior of sound field caused by the vibrating body. It is presented radiation modes and radiation efficiencies using relationship between surface normal velocities and surface sound pressure of vibrating structures and gives one definition of the weight coefficient of sound radiation. Radiation modes are dependent on the radiator geometry, but not on any material characteristic of the radiator itself. Radiation modes are orthogonal to one another and the sound power of each radiation modes is completely independent of one another. One of the important aspects of the radiation modes is their radiation efficiencies fall off very rapidly with the increase of modes of order at low frequencies.At present, controlling the transfer-function of the system and researching the control strategy are dominant in studying radiation modes. In this paper, the state equation of simply supported rectangular panel is established by using the control strategy that is canceling the first k radiation modes. The equation can satisfy MIMO(more in more out) system and the system with distribution in time-domain, frequency-domain and plural-domain. Then stability, controllable and observable of the system is discussed. Basing on the outcome, the system is stabilization, completely output controllable and completely observable. At last, using Matlab software to confirm the availability of the state equation of SISO(single in single out) system by controlling the first radiation mode through optimal control.