步长参数对电液伺服振动台加速度谐波抑制的影响

Impact of Step Size on Acceleration Harmonic Suppression of Electro-hydraulic Servo Shaking Table

电液伺服振动台存在非线性现象,导致系统作正弦振动时,其加速度响应信号中出现高次谐波,使加速度波形失真。利用LMS自适应滤波算法,提出自适应谐波抑制算法。通过对参考信号的自适应滤波作用,得到谐波抑制信号,并加入到系统输入信号中,从而抑制加速度响应信号中的谐波。从谐波抑制试验结果上看,自适应滤波器的步长参数对谐波抑制算法的收敛速率影响较大。从LMS自适应滤波算法本身出发,分析了导致这种影响的原因。

Because of the nonlinear characteristics of electro-hydraulic servo shaking table, its acceleration output corresponding to a sinusoidal input contains higher harmonics which cause harmonic distortion. Using LMS adaptive filtering algorithm, an adaptive harmonic suppression algorithm is developed. The reference signals are filtered by an adaptive filter to obtain the harmonic suppression signal adding to the system input and auppressing the harmonic in the acceleration response. The test results show that the step size of the adaptive filter affects the convergence rate of harmonic suppression greatly. The influence of LMS adaptive filtering algorithm itself is analyzed.