Optimum Control Study Of Electro-Hydraulic Servo Unit In Ship Rudder

In recent years, with the development of constantly large-scale, high automation, high-speed, environmental protection and safety in the ocean shipping, new ship hydraulic autopilots with high reliability, high durability, high precision and adapted to the rudder blade load torque characteristics, are widely used in 5 tons to 100 tons of merchant ships and military.Automatic steering gear is the basic components which contain electrical components, mechanical components, and hydraulic components. Electric-hydraulic servo unit is autopilot's "heart" components, which is put signals converts mechanical and hydraulic amplifier, signal and implement feedback control, realize the control rule, direct relation of the automatic control device for the whole performance, and has important influence on control accuracy and stability, is typical of the electromechanical integration of high-tech products.The previous test study of electro-hydraulic servo unit possessed zero oscillation and the asymmetric output trip phenomenon of differential cylinder, and there also possessed some problems in its tracking, stability and quickness. This paper has discussed the working principle of electro-hydraulic servo unit's each component part carefully, especially analyzed the interference factors of system and the error with detail, then set up a nonlinear mathematic model, and obtained the zero oscillation mechanism, finally proved the correctness of the mathematical model validation through comparing the simulation curves and test curves.In view of the above questions in a lot of domestic and foreign literature material, and on the basis of electro-hydraulic servo unit itself characteristic and actual requirements, this paper has ensured the corresponding quadratic performance indexes of the optimal control strategy.In order to solve the problems found in the experiment and simulation process, this paper has simulated in two kinds of situation without outside interference and interference. Simulation results show that the optimal controller to have solved main problems of the zero oscillation and differential cylinder around asymmetric trip. Using the optimal control instead of conventional PID control has greatly improved in the speed and stability and tracking of displacement output of piston rod, and a stronger adaptive ability and robustness.