结构声有源控制是抑制低频声辐射的有效方案,误差传感策略是实现该系统需解决的问题.通过矩形小块PVDF阵列采集结构表面振动信息实现波数变换,在波数域构建传感策略实现误差信号的检测.首先对平板的振动响应建模,然后以波数域辐射声功率为基础,通过对结构表面加速度或PVDF输出电荷作连续与离散波数变换来构建误差信号,实现误差传感策略.最后通过实例计算来验证误差传感方案的有效性,并给出其具体的实现步骤.结果表明,构建的误差信号与结构的辐射声功率信息相关性强,且用少量PVDF薄膜采样即可获得满意的降噪效果.
Active structural acoustic control is an encouraging approach to actively control low frequency sound radiated by vibrating structures.One of the key problems encountered when implementing such a control system is to sense the error signal,which should be highly correlated with the structural radiated power.Based on the wave number transform,error sensing strategy is constructed in wave number domain by sampling panel surface vibration on discrete points using an array of PVDFs.Firstly,the theoretical model of vibrational response is established.Then,the error signal is constructed based on acceleration or PVDF's output charge in wave number domain,respectively with a continuous and discrete approaches.Finally,results obtained demonstrate the feasibility of the proposed error sensing strategy.And the flow chart of implementing such strategy is also given.The error signal acquired is highly correlated with the structural sound power.And only a small number of sampling points or striped PVDFs is needed to achieve considerable noise reduction.