| With the development of marine resources, Underwater Vehicle has been developing rapidly. In this paper fuzzy PID velocity control strategy is studied for the valve-controlled motor of Underwater Vehicle propeller.Firstly, this paper analyzes the match of Underwater Vehicle, propeller, engine. The propeller is designed by figure method. The math model of valve-controlled motor system was established and analyzed, including selection of motor and servo valve, calculation of the system parameters , and the model building of the system open-loop transfunction. At last, the system is analyzed on bode figure.Through analysis, the system needs correction, firstly the system is controlled by conventional PID and the system parameter is tuned. Then the system is controlled by fuzzy self-tuning PID and the simulation model is established.Matlab software will be used to analyze conventional PID control and fuzzy self-tuning PID control, then the result of the two systems were compared. The comparison was complished in two condition. First, the step reponse of two systems (fuzzy self-tuning PID and conventional PID )was compared on the variation of the frequency parameter(ω_h=100 is changed intoω_h = 80) when the system is not loaded. Second ,the response of two systems was compared when the disturbance was imposed to systems immediately and the system is loaded. Qualitative and quantitative analysis of step curve is analyzed and the results are satisfying. |
