The Study Of Servo Control System For Unmanned Surface Vehicle Based On Fuzzy PID Control

The stability and autonomy of the Servo Control System determines the stability and safety of unmanned navigation.The Servo Control System is an important equipment for ship course control.Therefore,so far it is a hot research topic in the field of unmanned ship control to seek for the automatic Servo Control System which is safe and stable.PID control is widely used in industrial control,which has the advantages of simple structure,strong robustness and so on.However,the effect of PID control is determined by the adjustment of PID parameters Kp,Ki and Kd.Besides,PID control can not set parameters online,so PID control has no good adaptability for systems that can not establish precise mathematical model.Fuzzy control is a computer numerical control,which is based on fuzzy logic inference,fuzzy sets and fuzzy linguistic variables.What’s more,Fuzzy control belongs to the category of intelligent control.We found that as for some systems which is difficult to establish accurate mathematical model,experienced operators with manual control often can achieve satisfactory results.Of course,the core of fuzzy control is to use computer simulate people’s own decision-making process.Fuzzy control technology has been successfully applied in many control areas.The purpose of this paper is to improve the classical PID control which is not suitable for the complicated ship marine environment,and to realize the on-line tuning of PID parameters with fuzzy inference method,so as to improve the ship course control performance.This paper first introduces the basic principle of PID control and fuzzy control.Then in this paper,the incremental PID control algorithm,the fuzzy of variables,the establishment of fuzzy rules and the fuzzy reasoning and de-fuzzification methods are discussed emphatically.Moreover,this paper designs a set of ship course control based on ARM embedded system,and introduces the software and hardware composition of the control system.It also introduces the design of fuzzy control in detail.Combining with the common steering gear model and the Nomoto Saku ship model,in the Matlab environment the simulation structure diagram of PID ship course control system and fuzzy PID ship course control system is constructed by using the fuzzy reasoning system designed.The simulation results show that compared with the classical PID control,the fuzzy PID control method has faster system response and more stability.Generally speaking,it has better control effect.After field testing,we can see that the ship can arrive the preset track point by analyzing the longitude and latitude data of the path.It finally realizes autonomous cruise of ship,which proves the validity and stability of the ship control system.