Objectives  The energy fluctuation characteristics of the ship's active vibration isolation system is studied.

  Methods  Firstly, a generalized mathematical model of hybrid vibration isolation system with multi-dimensional composite perturbation vibration source, distributed parameter active-passive integrated vibration isolator, decentralized intermediate mass and elastic installation foundation was established, and the coupling vibration mechanism of the system was revealed from the perspective of acoustic vibration energy transmission and control. Then, combined with the application of the vibration isolation system in the actual project and setting the intermediate mass floating damper vibration isolation system as the reference group, the resonance in the isolator, the wave effect of the intermediate structure, the intermediate mass to machine mass ratio, and the effect of different actuator arrangements on the energy transfer of the system were studied.

  Results  The results show that the isolation effect of decentralized intermediate mass vibration isolation system on vibration energy is significantly improved compared with floating raft vibration isolation system, especially in the middle-high frequency resonance region, and the active control considering the actuator output constraints can effectively reduce the error of theoretical prediction made when no constraint is imposed.

  Conclusions  This kind of hybrid vibration isolation system has good vibration isolation effect in the whole frequency band, and its isolation ability exceeds that of the traditional vibration isolation system by about 15 dB, and the active control considering the output constraints of actuators is more suitable for engineering practice.