Research On Control Characteristics Of Direct Drive Fin Stabilizer

The direct drive fin stabilizer is an application of the electro-hydraulic servo control system in marine facilities. It has the advantages of compact, light, sample and easy to install.Compared with the traditional valve controlled electro-hydraulic fin stabilizer system, it is less susceptible to the contamination of the oil,it’s efficiency is high and be more quiet. So the direct drive fin stabilizer system is promising in using. But the response characteristic of system is not ideal. The paper carries out deeply research to the direct drive fin stabilizer system, which will be a basis to the following research.The paper introduces the development of fin stabilizer system and direct drive electro-hydraulic servo system domestic and abroad, analyses their characteristics by reference relevant literature.Firstly, he structure of the direct drive fin stabilizer system is researched by analyzing the principle of it. The close loop speed control motor system employed vector control technology is established based on the analyzing of the speed control principle of the induction motor. The characteristics of the pump control actuator is analyzed and it’s linear model is established. The model of the fin stabilizer system is obtained. The static error and dynamic error are analyzed and the method to reduce errors has been presented. The hydrodynamic load of the stabilization fin system is analyzed and the approximate method of calculating the static load of the system is presented, which provide a base for following simulation.Secondly, the parameters of structures of the direct drive fin stabilizer system are obtained according the technique requirements by referring to literatures. The parameters in simulation are obtained by mathematical method. Simulation analysis is done to the designed vector control variable speed regulation system, validating the rationality of the designed control system, to get the parameters of the speed regulation system. The Matlab/Simulink system model is established to analyze the stability and response characteristics of various typical input signals and analyzed. The reason of poor dynamic response characteristic is analyzed. A PID controller is designed, response characteristics are analyzed by simulations in time domain and the effect of the controller is analyzed.Finally, a fuzzy PID adaptive method is presented in consideration of the poor frequency response characteristic and effect of the turbulent. The parameters of the PID controller are optimized by the fuzzy logics on line. According to the simulation results, the PID controller improves the performance of the system under turbulent, and the dynamic response characteristic of the direct drive fin stabilizer system turned to be better.