The active vibration isolation control problem under multi-frequency fluctuant line spectrum excitation was studied

and an improved wavelet packet adaptive control algorithm was proposed. It was difficult for traditional adaptive algorithms to control multi-frequency line spectra at the same time. Narrowband filtering algorithms also could not achieve good effect under fluctuant frequency excitation. Therefore

the wavelet packet decomposition algorithm was introduced to the control algorithm to divide the signal into equally spaced frequency bands. And then

a parallel control strategy was adopted to control multi-frequency line spectrum. The influence of different wavelet basis functions on signal decomposition was analyzed

and the optimal wavelet basis was determined. Aimed at the problems caused by the virtual line spectrum and too many sub-bands

the wavelet packet decomposition algorithm was improved to reduce the calculation amount and eliminate the virtual line spectrum in the sub-band. An independent step size was set for each sub-band

and modified according to the tongue-line function. The control system was build to carry out experiment. The results showed that the improved wavelet packet adaptive algorithm proposed in this paper can achieve good control effect under multi-frequency fluctuant line spectrum excitation

and the vibration energy of line spectrum was significantly reduced.