Research On Design And Fault Diagnosis Of Fin Stabilizer Hydraulic Servo System

The fin stabilizer is a ship stabilizing device which can decrease the ship rolling effectively and ensure the navigational safety. The composition and control technology of its hydraulic system are comparatively complex. These make the maintenances of fin stabilizer more difficult. The fin stabilizer fault diagnosis system is developed with expert system technology summarizing the experts' experiments. The aided diagnosis is much necessary to the fin stabilizer system fault diagnosis.The function and development stage of the ship stabilizing device are summarized firstly in the paper. The function, development and investigation status of fin stabilizer are introduced. The working principle of forced-rolling and stabilization is researched. Based on the purpose and significance of fault diagnosis, this paper introduces the development status of fault diagnosis and its application to hydraulic system. This provides the theoretical basis for fault diagnosis expert system of fin stabilizer hydraulic system.The composition of NJ5 fin stabilizer system is analyzed in this paper. According to the function of hydraulic system, it is divided into servo system, manual system and complement system. The function and working principle of each system are introduced respectively. Based on the operation requirement of a fin stabilizer hydraulic servo system, the actuating unit is engineering designed with the load matching concept of hydraulic control system. And the hydraulic parts of fin stabilizer hydraulic servo system are selected. Thus the fin stabilizer hydraulic servo system is composed and this offers the foundation of modeling. Through the analysis of the working principle of fin stabilizer hydraulic servo system controlled by pump, the models of variable displacement pump and its displacement control system are established. On this basis, the actuating unit and system transfer function models of fin stabilizer hydraulic servo system are set up. After substituting the parameter of hydraulic components to the model, the simulation of displacement control system and fin stabilizer hydraulic servo system are executed. The control performance of displacement control system and fin stabilizer hydraulic servo system are analyzed. It's showed by the simulating curves that the controller of fin stabilizer hydraulic servo system can meet system performance requirements with disturbance.To improve the maintenance and train personnel, the fault diagnosis expert system of fin stabilizer hydraulic servo system is proposed according to the kind, characteristics and classification of common hydraulic faults. Through the research of idea and construct of fault diagnosis expert system, its knowledge base model and reasoning mechanism are established. The fault diagnosis expert system of fin stabilizer hydraulic servo system is actualized with the object-oriented technology.