Research On Closed Water Chamber Pressure System Controlled By Electric Hydraulic

With the need of deep ocean technology development,underwater products have more widespread application in the future.Deep ocean environment monitoring testbed has great influence on the research and development of underwater products,and close water chamber pressure control system is the key of the deep ocean environment monitor testbed;precision of control system is the core parameter of accessing testbed ability.Based on the closed water chamber pressure system,this thesis aims to increase the control precision of the closed water chamber system.Based on the disadvantages of testbed about this area at present,for example,there are problems such as high cost but low ability to resist pollution in the system with water hydraulic components;pressure systems based on mechanical pressure transmitting device have the disadvantage of the low precision due to non-linear component affection;closed water chamber pressure system controlled by electric hydraulic at present needs to optimize its control algorithm;based on closed water chamber pressure system controlled by electric hydraulic,this thesis used electric servo valve and pressure transmitting device and proposed the control strategy of adaptive PID based on Fuzzy.This thesis is meaningful to the engineering application of this area.This thesis completed the design of closed water chamber pressure system based on electrical hydraulic;mathematical model of closed water chamber system was constructed and analyzed.Based on model simulation,factors which could affect this pressure control system were analyzed to support hardware design and control strategy;adaptive parameter PID based on Fuzzy was proposed for this system;based on the model simulation,PID parameters were given and the strategy of adaptive PID based on Fuzzy and normal PID was compared;meanwhile,the hardware system of the closed water chamber pressure system was designed.The development of xPC target real-time control software system based on Winform was completed and the testbed of this system was constructed successfully;based on testbed,the experiment of adaptive PID was conducted with different conditions,including stable condition,dynamic condition and typical working condition.The research content is followed as below:The first chapter is about the development condition of closed water chamber system and electrical servo control system at present,and methods about pressure control and control strategy are given.Research aim and research content were proposed at last.The second chapter analyzed the application condition of closed water chamber pressure system and integrate design about this system was proposed,based on electrical servo valve and pressure transmitting device;hydraulic components were designed and the working process of system was analyzed at last.The third chapter constructed the mathematical model and analyzed the factor affecting the pressure control system;controlled model was constructed based on AMESim software and factors about leakage and property of servo valve were analyzed to support the future hardware design and control strategy design.The forth chapter proposed the aim and method of whole control system.Based on the PID control strategy,the affection of PID parameters on the system was analyzed;based the model of last chapter,PID parameters were given by using the steady state boundary method;meanwhile,the adaptive PID based on Fuzzy was proposed.Based on the model of last chapter,the simulation of two strategy was compared.The fifth chapter designed the hardware system of closed water chamber system and developed xPC target real-time control software system based on Winform;testbed about this system was completed and the experiment of adaptive PID based on Fuzzy was conducted with different conditions,including stable condition,dynamic condition and typical working condition.The sixth chapter summarized the research work of this thesis and proposed the future work in this area.The result of simulation in this thesis indicated that adaptive PID based on Fuzzy has better quality than the normal PID based on this system.Furthermore,the experiment on this testbed indicated that closed water chamber pressure system using adaptive PID based on Fuzzy has good quality in the stable condition,whose error is limited to ±0.04MPa,and this system can follow the control target curve line without distortion and its error is limited to ±2.5%FS in the dynamic condition.