Research Of Fuzzy Temperature Controller

With the development of society and technology, control level of the system needs to be more and higher in modem engineering. So, conventional control theory can not meet this requirement. In this background, fuzzy control theory is widely applied.Fuzzy control uses fuzzy mathematic depict the fuzzy definition as process variable or control function and their relationship, then based on the fuzzy rulers and the input and output of control elements, calculates controller outputs, so as to get the optimized control result. Fuzzy control is suit for nonlinear and hysteretic system whose model is unknown.The fuzzy temperature controller introduced in this paper control the temperature of control object with hysteretic property. The paper introduces the hardware and the software design of he controller. The main controlling part of the controller is based on single-chip PIC18F252 which is produced by Microchip company. PIC collects temperature signal, carries out the fuzzy control arithmetic and sends the control outputs. The single-chip integrates AD module. Temperature test circuit is based on Ptl00 sensor, and compensates it. The part of keyboard and LED display is based on 8-bit-high-performance AT89C52 which is produced by ATMEL company. The two single-chips communicate the data with Serial Communications Interface (USART). As for software, fuzzy control is used as the kernel arithmetic, and C language is used to compile the whole program.The result of the experiment shows that, compared to the conventional control, fuzzy control has lots of strongpoint such as the short adjust time, the smooth intergradations, and the well anti-interference.