ROBUSTNESS OF A FEEDBACK ACTIVE NOISE CONTROL

摘要

This work investigates the robustness of a feedback active noise control system. In order to solve any noise control problem we have to provide the appointed amplitudes of secondary sources. These amplitudes are formed by the feedback transfer function with the aid of the signal from sensors placed in the vicinity of the sources. In almost all practical cases the actual transfer function differs from required one because of various reasons. It is very important to estimate the effect of errors of the transfer function value on the active control efficiency. The robustness of the active system consisting of one secondary source connected with one sensor by the feedback is analyzed. It is shown that the active system is least sensitive to the errors when the feedback is deep. As an example of the active control with the deep feedback we consider the system consisting of the monopole source and monopole sensor applied for reduction of noise radiated by the duct outlet. The quantitative parameter characterizing the system robustness is proposed and estimated both theoretically and experimentally. The active control systems with deep and weak feedback are compared as well. Disadvantages of the deep feedback control systems are discussed.