Design And Research Of Liquid Level Fuzzy Control System Based On CAN Bus

Fuzzy control, an important branch of intelligent control, is paid great attention since it appeared. The purpose of this thesis is how to apply fuzzy control to practical manufacture with some common components. In this thesis, the circuit of liquid level fuzzy controller is presented based on liquid level control system and with AT89S51 as control chip. The other important components include complex programming logic device XC9536, temperature detection device DS18B20, D/A converter AD420 and so on. The principle circuit and PCB(printed circuit board) are designed with protel 99, and the whole controlling program written by assembly language is debugged. According to the experience obtained through the debugging, summarization is given to anti-jamming and fault-tolerance of this software in the single-chip processor control system. CAN bus interface of fuzzy controller is designed with chip SJA1000 in order to enhance the communication ability and keep the RS232/485 communication mode to which was accustomed before. This fuzzy controller can be applied to both centralized control system and distributed control system. In fuzzy controller designing, the selection of membership function and control rule have considerable subjectivity and randomness, so some parameter need to be modified over and over again. Genetic algorithm is introduced in the designing of fuzzy controller, which can solve the original drawbacks and make the designing more effectively. The paper present software compiled with MATLAB about applying improved genetic algorithm to optimize membership function of fuzzy controller, furthermore, doing research in emulation.