一种基于改进FxLMS算法的低频正弦振动控制技术研究

Research on Low⁃frequency Sinusoidal Vibration Control Algorithm Based on Improved FxLMS

针对经典正弦振动试验控制算法在较低频段(如0.1~5 Hz)存在幅值估计时间长、估计精度低等问题,研究一种基于改进FxLMS算法的低频正弦振动控制算法,利用自适应机制,同时实现了标准振动台系统传递特性的在线辨识和驱动信号的逐点修正,提高了正弦试验的幅值控制精度和稳定时间。利用数值仿真研究了收敛因子对算法收敛速度的影响,完成了对比实验。结果表明:在0.5 Hz频率正弦振动试验中,仅需10 s即收敛至5%的幅值精度,显著优于逐步逼近算法,证明了改进FxLMS算法可以很好地满足低频正弦振动试验对幅值控制精度和实时性要求。

In view of the problems of long amplitude estimation time and low estimation accuracy of classic sinusoidal vibration test control algorithms in low frequency bands(such as 0.1~5 Hz), a low-frequency sinusoidal vibration control algorithm was studied based on the improved FxLMS algorithm.Using the self-adaptive mechanism, the online identification of the transfer characteristics of the standard shaker system and the point-by-point correction of the drive signal were realized at the same time, and the amplitude control accuracy and stabilization time of the sine test were improved.The effect of the convergence factor on the convergence speed of the algorithm was studied by numerical simulation.The comparative experiment was completed.The results show that in the 0.5 Hz frequency sinusoidal vibration test, it only takes 10 seconds to converge to 5% amplitude accuracy, which is significantly better than the traditional stepwise approximation algorithm. It is proved that the improved FxLMS algorithm can well meet the requirements of amplitude control accuracy and real-time performance in low-frequency sinusoidal vibration test.