The Research Of Intelligent Temperature Control System Of Resistance Furnace Based On Virtual Instrument

With the development of science and technology, the application of electronic measurement technology has extended to more fields than before. Due to limited functions and big size, traditional electronic measuring equipments are no longer suitable to demand of measurement in practice. With the rapid development of integrated circuit and computer technology, a new kind of instrument, Virtual Instrument (VI), came into being in the end of the 80s. Compared with traditional equipment, VI characterizes with more functions, higher processing speed, higher efficiency and better expandability. As the integration of computer technology and modern instrument technology, virtual instrument make the revolutionary breakthrough in the conventional measuring theory and technique.Resistance furnace is a kind of non-linearity, time variability, and large time log object. It is very difficult to express its characteristic using precise mathematic model. So we can't obtain the high-performance using the conventional PID control method. The neural network and genetic algorithms is based on non-mathematic model, that is to say we need not establish the accurate mathematic model of the object. This thesis has studied the inherent mechanism of the temperature control system of resistance furnace, considering kinds of element, established the mathematic model of resistance furnace and proved that of temperature control system of resistance furnace is single-order large time log object.This thesis has studied the characteristics of conventional PID control, neural network and genetic algorithms respectively. The self-turning PID controller based on genetic algorithm and neural networks is designed. The controller combines the conventional PID control with genetic algorithms and neural network organically. The three parameters of PID controller can be automatically calculated. It avoids the trouble of manual work. The simulation results demonstrate that the self-turning PID controller based on genetic algorithm and neural networks has more advantages for systems of single-order large time log object, such as more brief structure, more rapid response speed, higher control precision, more stable.Virtual instrument and the technology of intelligent temperature control system is combined in this paper. The temperature control system of self-turning PID controller based on genetic algorithm and neural networks is designed by Virtual Instrument. The development and status about intelligent temperature control system are first summarized. Then the development and outstanding characteristic of virtual instrument are deeply presented, and the designing method and realization of the intelligent temperature control system are discussed in detail subsequently, including designing and realization of data acquisition, data disposal, data storage, and so on. The improvement of measure precision, reliability and work efficiency is testified by the practice of the system that validates the correctness and feasibility of the design idea and method and shows the superiority and brighter development foreground of Virtual Instrument than traditional instrument. Finally all the work of this dissertation is summarized and the future research work is prospected.