EXPERIMENTAL ACTIVE NOISE CONTROL OF DUCT SYSTEM USING CO-FXLMS ALGORITHM

摘要

The method of the reduction of the duct noise can be classified by the method of passive control and the method of active control. However, the passive control method has a demerit to reduce the effect of noise reduction at low frequency (below 500Hz) range and to be limited by a space. Whereas, the active control method can overcome the demerit of passive control method. The algorithm of active control is mostly used the Least-Mean-Square (LMS) algorithm because the LMS algorithm can easily obtain the complex transfer function in realtime. Especially, When the Filtered-X LMS (FXLMS) algorithm is applied to an ANC sys-tem. However, the convergence performance of LMS algorithm goes bad when the FXLMS algorithm is applied to an active control of duct noise under rapidly accelerated conditions. Thus Correlation FXLMS (Co-FXLMS) algorithm was developed to improve the control performance under the rapid acceleration. The Co-FXLMS algorithm is realized by using an estimate of the cross correlation between the adaptation error and the filtered input signal to control the step size. In this paper, the performance of the Co-FXLMS is presented in comparison with that of the FXLMS algorithm. Experimental results show that active noise control using Co-FXLMS is effective to reduce duct noise under the rapidly accelerated conditions.