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误差非线性函数的变步长FxLMS算法研究

Research on variable step size FxLMS algorithm based on error nonlinear function

  • 摘要: 滤波-x最小均方(Filtered-x Least Mean Square,FxLMS)算法是主动噪声控制的经典算法,其存在收敛速度与稳态误差不可兼得的问题,解决方法之一是采用变步长FxLMS算法。总结了现有的基于误差非线性函数的变步长模型,并将其应用于FxLMS算法以改善算法性能。用三种常见的噪声作为参考输入信号进行仿真试验,对比了不同非线性函数变步长算法的性能。结果表明,变步长FxLMS算法能有效改善参考信号为高斯白噪声和正弦波时的收敛速度和稳态误差,且不同噪声环境下最优算法不同,但此类算法无法提升噪声源为冲击噪声时的性能。这为不同应用场景下算法的选取提供了参考。将变步长FxLMS算法应用于某车型的发动机主动噪声控制,结果表明,变步长FxLMS能显著提高定速工况的系统性能,但对急加速工况效果并不明显。

     

    Abstract: The filtered-x least mean square (FxLMS) algorithm is a classical algorithm for active noise control, however, the incompatibility problem between the convergence speed and steady-state error needs to be solved. One of the solutions is to use the variable step size FxLMS algorithm. The existing variable step size models based on the nonlinear function of error signal are summarized and applied to the FxLMS algorithm to improve the performance of the algorithm. Three common signals are used as reference input signals to carry out simulation experiments and the performance of variable step size algorithms with different nonlinear functions is compared. The results show that the variable step size FxLMS algorithm can achieve faster convergence speed and lower steady-state error when the reference signals are Gaussian white noise and sine wave, and the optimal algorithms are different under different noise environments, furthermore, the variable step size algorithm cannot improve the algorithm performance when the reference is impulsive noise. This research provides a reference for the selection of algorithms in different application. The variable step size FxLMS algorithm has been applied to the active noise control of a certain vehicle, and the results show that the variable step size FxLMS can significantly improve the system performance in constant speed condition, but its effect in rapid acceleration condition is not prominent.

     

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