基于时域声辐射模态的结构噪声主动控制研究

Active control of acoustic radiation based on time radiation modes

以平板为例,在时域里对声辐射模态进行了初步研究.研究表明时域声辐射模态既与时间无关,也互相独立,使得计算和控制声功率得以简化.针对瞬时声功率主要由第一阶辐射模态的声功率所决定的特点,在时域里进行结构噪声的主动控制研究,提出了新的主动控制策略,即通过抵消第一阶辐射模态的声功率使得总的声功率得以有效降低.在此基础上,建立基于FXLMS算法的自适应前馈控制系统,进行仿真计算,结果证明了主动控制策略是有效的.

In the time-domain, a new formulation is developed for calculating the radiation modes of a baffled planar source. These modes are only dependent on the radiator geometry, but not on time. (According) to the fact that the sound power of the first radiation mode is dominant in transient power, a control strategy in time-domain is developed in which by canceling the adjoint coefficent of the first radiation mode, the sound power of the first radiation mode is decreased effectively. Finally, an adaptive feedforward control system based on FXLMS algorithm is developed to control the adjoint coefficient of the first radiation mode. The simulation result verifies that the proposed method can actively suppress transient structural acoustic radiation.