Research On Active Noise Control Technology Based On Quaternion Adaptive Filter

Continuous and excessive noise exposure can have serious physical and psychological effects on the human body.Commonly used passive noise control technology can play a very good attenuating effect on high frequency noise,but there are obvious shortcomings in the control of low frequency noise reduction.Compared with passive noise cancellation,active noise control(ANC)system is an effective technology for controlling low-frequency noise.Among them,the filtered-x least mean square(FxLMS)algorithm for processing one-dimensional signals has been widely adopted by ANC systems due to its simplicity and robustness.Based on the FxLMS algorithm,people have proposed different types of controller structures and algorithms.This paper extends one-dimensional signal processing to a multi-dimensional space,proposes a quaternion-based feedforward active control noise reduction system,and designs an active noise control technology based on the filtered-x quaternion least mean square(FxQLMS)algorithm,and On the basis of the fixed step size FxQLMS algorithm,combined with the adjustment of the variable step size,a variable step size filtered-x quaternion least mean square(VSSFxQLMS)algorithm is further proposed to optimize the performance of the algorithm.And through the comparison of computer simulation results,the effectiveness of the algorithm improvement is verified.The main research contents of the thesis are as follows:(1)Research and derivation are carried out around the principle,system structure and basic algorithm of ANC technology,and the problems existing in the current ANC system and the future development prospects are analyzed.Focus on the principle of the FxLMS algorithm and the implementation process of the algorithm,and classify and discuss the identification methods of the secondary acoustic path,and finally build the identification algorithm of the additional white noise method and the Simulink model based on the FxLMS algorithm to complete the identification of the secondary channel and the noise control of the ANC system.(2)A noise control technique based on the quaternion filtered-x least mean square(FxQLMS)algorithm is proposed.This control scheme is improved from the FxLMS algorithm.On the basis of the feedforward system,combined with the quaternion adaptive filter,a noise control system based on the FxQLMS algorithm is established.The research and derivation of the proposed algorithm structure principle and weight update formula were carried out respectively.In order to verify the effectiveness of the algorithm,a control system model based on the FxQLMS algorithm was established.FxQLMS algorithm has better convergence performance than FxLMS algorithm in the case of state error.(3)In order to obtain a better noise control effect,an active control technique based on a quaternion adaptive filtered-x least mean square(VSSFxQLMS)algorithm combined with variable step size adjustment is further proposed.The algorithm balances the steady-state error and convergence performance of the algorithm by establishing a functional relationship between the step size and the error signal.The purpose is to optimize the convergence step size of the FxQLMS algorithm from a fixed value to a variable step size adjustment to achieve better adaptation.The adjustment process.The variable step size in the algorithm is improved from the classic variable step size scheme.The functional relationship between the two methods is studied in the article.Finally,modeling and simulation verify the effectiveness of the improved variable step size method,and the simulation results are compared.It is concluded that the VSSFxQLMS algorithm has better convergence performance than the FxQLMS algorithm under the same ANR.