A FREQUENCY ESTIMATION METHOD BASED ON IMPROVED ADAPTIVE NOTCH FILTER ALGORITHM FOR ACTIVE VIBRATION CONTROL

摘要

High-precision estimation of the multiple-harmonic frequency through real-time collected vibration signals is an important prerequisite for achieving active vibration control. To obtain the periodic or quasi-periodic frequencies as reference signals, a second-order infinite impulse response (IIR) notch filter based on variable step-size unbiased plain gradient (VSSUPG) algorithm was designed. Take a sinusoidal signal with noise as input signal, the frequency is estimated by adjusting the notch frequency. An adaptive step changing method of notch filter is used to improve the speed and accuracy of estimation. Simulation results showed that the proposed adaptive notch filter has faster estimation speed and smaller steady-state error than traditional adaptive notch filters algorithm. Compared the VSSUPG notch filter with the Fast Fourier Transform (FFT) and the ratio correct FFT frequency estimation response characteristics under different SNRs, results show the VSSUPG notch filter has a better estimation accuracy. It is suitable for online estimation of the periodic and quasi-periodic frequency through real-time collected vibration signals in active vibration control.