Improvements on Robustness of Feedback Active Noise Reduction Earphone

In feedback active noise control with fixed controllers, noise reduction performance and stability of feedback system are affected by changes on secondary path. For active noise reduction earphones, disturbance and uncertainty of the secondary path will be caused if the tightness or direction of the earphones changes. Therefore, it is necessary to measure several secondary paths to obtain one nominal secondary path before designing controllers, and the constrain on the stability of the feedback system should be made to ensure the robustness of the system. In this paper, improvements are made on the selection of nominal secondary path and disturbance weighting function on the basis of robust control theory. The optimized method makes it possible to achieve higher noise reduction on the premise of ensuring the stability of the feedback system. The robustness of feedback system is improved, and the maximum disturbance to noise reduction performance is reduced.