Active control of sinusoidal noise (formulation of control algorithm and stability condition)

• Published in: Nihon Kikai Gakkai ronbunshū. C Vol. 63; no. 606; pp. 423 - 430
• Main Authors: Nakamura, Mitsuru, Sasaki, Minoru, Fujisawa, Fumio, Tsukahara, Daisuke, Yamada, Yasunori, Shibata, Kiyosei
• Format: Journal Article
• Language: Japanese
• Published: 01.01.1997
• Subjects: Acoustic noise; Adaptive algorithms; Computer simulation; Microcomputers; Notch filters; System stability
• ISSN: 0387-5024

This paper describes a formulation and stability of the modified LMS algorithm for active periodic noise control. A typical application of active noise control is the control of engine-induced noise inside cars, which synchronizes with the rotating speed of the engine crankshaft. This modified algorithm effectively decreases the operating time of the filter coefficients in a single computational step. We applied the active noise control system using the filtered-x adaptive notch filter algorithm. Numerical simulation results reveal the stability limits of the step size parameters for the successful implementation of this control system. An analysis of these results also show that a smaller control pulse number lead to faster convergence and consequently, larger step size parameters being able to be used. This, in essence, promotes the implementation of such algorithms using the more commonly used cheap microprocessors. The results also indicate that the filtered-x adaptive notch-filter algorithm has higher stability and faster response than other algorithms.