Research On Structure Invariance Principle In Loading Simulator Of Fin Stabilizer

The electro-hydraulic load simulator of fin stabilizer simulates equipment of wave load when fin stabilizer moves in the laboratory. Its function simulates wave force that fin stabilizer is impressed under different angle of attack so as to detect technical performance index of the driving system of fin stabilizer. It is a half-prediction research that converts traditional material experiment into laboratorial condition in order to reduce developing period and economize developing fund and increase reliability and successful rate. Along with the development of sea national defense and ship industry, the electro-hydraulic load simulator of fin stabilizer with high performances is urgently demanded. Because the electro-hydraulic load simulator of fin stabilizer is a kind of typical passive electro-hydraulic force servo system, large surplus force caused by strong disturbance of fin stabilizer displacement seriously affects the static and dynamic performances of the electro-hydraulic load simulator. Now the key point is how to eliminate surplus force and improve static and dynamic performances of the electro-hydraulic load simulator.After synthesizing numerous related literatures and reference materials home and abroad, the development of domestic and oversea electro-hydraulic loading system is summarized, and the merit and shortcoming is analyzed. The studying direction is decided through comparing domestic products and overseas products.In this dissertation, we build up mathematical model of the electro-hydraulic load simulator of fin stabilizer, obtaining mechanism and characteristics of surplus force through analyzing mathematical model of the electro-hydraulic load simulator, which can establish theoretical foundation to increase control performance of electro-hydraulic load simulator. The conclusion is obtained that surplus force is influenced by speed and acceleration of electro-hydraulic load simulator.Driving elements of fin stabilizer are designed and the simulation about characteristics of surplus force, loading system with or without disturbance, static or dynamic state is done. The relationship between dynamic characteristics of servo valve and loading system's control performance, loading gradient and loading system's control performance is analyzed. Using structure invariance principle, control link is designed to eliminate surplus force and to improve the control performance of loading system.The experimental system is build up in this dissertation. Through experiments,we obtain receives static and dynamic performances of fin stabilizer, which can prove that the methods advanced in this dissertation is effective for improving comprehensive control performances of the electro-hydraulic load simulator.