Many active noise control (ANC) systems are based on feedforward (FF) control. However, recently, research on feedback (FB) ANC and two-degree-of-freedom (2DOF) ANC (hybrid ANC of FF and FB) has been conducted, because the importance of FB control has been recognized. We report 2DOF ANC aimed at improving control performance and focus on FB control. Since the system between a loudspeaker and an error microphone has a time-delay, we propose 2DOF-ANC with internal model control (IMC) in FB control. This IMC is known as a robust control design method especially for dead-time systems such that process control systems. Also, we discuss FB-ANC from the control theory point of view. It is shown that a howling canceller in ANC is equivalent to IMC, that the zeros which lie in the right half-plane in FB-ANC are closely related to the attenuation performance, and that the performance of FB-ANC can be predicted by investigating the sensitivity function. Moreover, a robust FB-ANC design method based on IMC is described and its effectiveness is demonstrated through a numerical example.
|Nippon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C
|Published - 1997 1月 1
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