Study On Synchrophasing Control Of Marine Floating Raft Vibration Isolation Structure Supporting Multi-motor System

The vibration caused by the operation of the power equipment on the ship has a great negative effect,which seriously reduces the comfort and combat ability of the ship.As an effective vibration isolation technology,floating raft has been widely used in various submarine and transport ships.Existing floating raft vibration isolation techniques can be divided into active and passive vibration isolation.The difference between them is whether a controller is installed to intervene with the support body.Both of methods do not consider the coupling effect between the exciting forces in the system and ignore the possibility of using the coupling effect between the exciting forces to reduce the vibration.In this paper,a double-decked floating raft vibration isolation system under multiple excitation is studied.The multi-motor driving the eccentric rotor in the system are controlled by synchronous phase control,and the relationship between the excitation forces in the system is adjusted,so as to improve the performance of the floating raft vibration isolation system.Firstly,the electromechanical coupling dynamics model of the whole system is established by combining the motor models of several permanent magnet synchronous motors with the dynamics model of the double-decked floating raft system using Lagrange equation.Through the electromechanical coupling model,the vibration isolation problem of complex system can be transformed into the synchronous phase control problem of multi-motor.In order to realize synchronous phasing control of multi-motor,the motor torque and flux controller is designed based on super-twisting sliding mode algorithm,and the fuzzy sliding mode controller is designed on the basis of the improved master-slave parallel structure to realize the position and speed tracking control.In order to satisfy the need of stable position difference,a cross-coupled position compensator is added to the original control structure.Then the stability of the controller is proved by Lyapunov theorem.Finally,numerical analysis software is used to verify the effect of the control system,and the performance of vibration isolation under synchronous phase control is analyzed.The results show that the designed controller can control the stable and synchronous operation of multiple motors,and the position difference between the rotors of the motors can be maintained.By comparing the effect of active and passive vibration isolation,the feasibility of using the coupling effect between excitation forces to reduce vibration is verified.In addition,the influence of eccentric rotor mass on vibration isolation effect is discussed,and the influence of elastic connection between motors and raft on vibration reduction effect is analyzed considering the particularity of double-decked structure of floating raft system.The research of this paper can be used as reference for improving the effect of floating raft isolation system and other vibration reduction facilities.