Study on the Servo System of Zero Speed Fin Stabilizer Based on PM Synchronous Motor

Hydraulic servo system is normally adopted for the existing fin stabilizers of ships at zero speed. However, there are many disadvantages coming from hydraulic servo system. In order to overcome these shortcomings in operation, the application of electrical servo system to fin stabilizer is discussed so that to improve the capability of the servo system. Suitable driving motor and main circuit is chosen for fin stabilizer at zero speed based on the loading characters and the requirement for the driving power. According to the sequence as from inner loop to outer loop, the configuration and parameters of adjuster are set. The nonlinear PID controller is designed to reduce the affects caused by the ripple of torque. A practicable method to set up the parameters is proposed. The electrical servo system is simulated on the Matlab. The simulation results indicate that the system has excellent dynamic performance, and it can be well applied to the fin stabilizers at zero speed.