Study Of Temperature Control System Based On Self-tuning PID Controller

PID control is one of the developed firstly control strategies.Up to now,PID control is the most common control method.At present,PID control and improved PID control strategies have been widely used in industrial control system for its simple structure and strong robustness.In PID control,the effect of the control is good or bad depends entirely on the PID parameter tuning and optimization. Routine PID control is good in the control of the basic linear and dynamic system, however,routine PID control is often poor in the control of non-linear, time-varying system.Temperature controller has the characteristics of non-linear, great lagging, big inertia,time varying and unidirectional rising.Traditional PID control is therefore unable to achieve effective control and intelligent PID began to be used to temperature control system.With the development of computer technology and the theory of intelligence computations,the theory of the intelligent control is applied to more and more improve the performance of PID controller. Fuzzy control and neural network has its own advantages.They are both can tune PID parameters and improve the performance of PID controller.In this paper,fuzzy control and neural networks is combined to form the fuzzy neural network for tuning the three parameters of PID.A structure of fuzzy neural network PID controller is designed,based on this DSP-processor implementation with control system of the function of self-tuning PID temperature.System is as follows.In the module of the power supply,chip TPS76833 is used to the power conversion.In the module of the measurement of temperature`s voltage,Pt100 temperature sensor and its corresponding temperature measurement bridge is used to voltage acquisition and analog-to-digital conversion units of DSP is applied to conversion from analog to digital.In the module of the Human-Computer Interaction,I/O of DSP is used to design a keyboard as an input and dot-matrix liquid crystal display MG-12232 is used.In the PC-interactive context,a MAX-232 driver chip which supports RS-232 standard is used to drive DSP and PC-driven serial communication.In the module of the temperature control,control volume is used to control the duty cycle control signal of wave PWM and the duty cycle signal is outputted to control the conduction of the power module to achieve the purpose of temperature control.Finally the procedures of the temperature control system based on the self-tuning PID controller is designed and implemented.