Reducing the vibration of marine power machinery can improve warships' capabilities of concealment and reconnaissance. Being one of the most effective means to reduce mechanical vibrations, the active vibration control technology can overcome the poor effect in low frequency of traditional passive vibration isolation. As the vibrations arising from operation of marine power machinery are actually the frequency-varying disturbances, the H 1 control method is adopted to suppress frequency-varying disturbances. The H 1 control method can solve the stability problems caused by the uncertainty of the model and reshape the frequency response function of the closed loop system. Two-input twooutput continuous transfer function models were identified by using the system identification method and are validated in frequency domain of which all values of best fit exceeds 89%. The method of selecting the weighting functions on the mixed sensitivity problem is studied. Besides, the H 1 controller is designed for a multiple input multiple output (MIMO) system to suppress the single-frequency-varying disturbance. The numerical simulation results show that the magnitudes of the error signals are reduced by more than 50%, and the amplitudes of the dominant frequencies are attenuated by more than 10 dB. Finally, the single excitation source dual-channel control experiments are conducted on the floating raft isolation system. The experiment results reveal that the root mean square values of the error signals under control have fallen by more 74% than that without control, and the amplitudes of the error signals in the dominant frequencies are attenuated above 13 dB. The experiment results and the numerical simulation results are basically in line, indicating a good vibration isolation effect.

The floating raft active vibration isolation system itself is a complex system with high nonlinearity, strong coupling, and multi-source excitations, so it is difficult to build a mathematical model and control the system. As an intelligent control method, the fuzzy control algorithm can provide an intelligent path for the active control of the complex floating raft system. In this article, the system identification method is adopted to establish the discrete transfer function mathematical models for the floating raft active vibration isolation system. And then for the purpose of simulation and experimental study, the fuzzy controller is designed based on dual inputs of the acceleration and its variation and single output of control voltage. Since the control effect cannot be optimized due to the fact that the quantization factors and scale factors are usually gained by trial and error method and the control rules are designed by expert experience, the quantization, scale factors, and control rules are simultaneously optimized by adopting the genetic algorithm in which hybrid coding is conducted for both real numbers and integers. The simulation and experimental results show that the fuzzy controller based on genetic algorithm is superior to the conventional fuzzy controller on vibration suppression effect.