The Study On Intelligent Control Algorithms To Anti-Rolling Fin

The thesis mainly discusses on three intelligent control algorithms used in ship anti-rolling fin.Ship anti-rolling fin is a successful compound of modern bionics and control theory in ship engineering and also one of the most widely used anti-rolling apparatus. It gets the transverse information through the sensors, converting it into fin-angle information, driving the fin by hydraulic system. With the control system, it produces the counteracting torque and achieves ship stabilization. Anti-rolling fin system in engineering usually uses the classical PID controller.Firstly, the random wave model is introduced and numeric simulation is established. PID control algorithm for anti-rolling fin is adopted as a comparative test bed and simulating responding curves are given. Then three control algorithms are proposed on the basis of a great deal of reference literatures. Based on normal fuzzy controller, the hybrid algorithm of fuzzy logic and integral function is presented, the simulation results show it gives better performance than PID controller. Aiming at the flaw of normal BP algorithms, a improving algorithm (RPROP) is brought forward. On the basis of the right updating values is modified directly, RPROP can improve the training rate enormously, and achieve optimal converging time without need of selecting original parameter. This algorithm also gains favorable performance in control of ship anti-rolling fin. Finally, adaptive network-based fuzzy inference system (ANFIS) is applied to above control system. ANFIS can produce fuzzy rules from sample data directly and is originally combination of fuzzy inference system and neural network. So it is well suitable for some complex industry control processes lacking of expert experience. Because ANFIS can realize the combination of fuzzy quality and numeric quantity, and both of its parameters and weights adjusted have clear physics meaning, it's much easily to be understood, mastered and applied by control engineers. So ANFIS has been great promising for industry application. The simulation demonstrates the ANFIS algorithm using in anti-rolling fin can achieve better control results than all other former two algorithms.