Abstract: Comparing to the drawbacks of fly ash constant current conveying system, the advantages of constant pressure delivery system and its conveying theory were introduced. A scientific modeling of the key of PID controller was established. By introducing the fuzzy control algorithm, the fly ash constant pressure conveying fuzzy adaptive PID controller was designed, which could make the auto changes between the fuzzy control and PID controller come true, and the simulation with MATLAB was researched. The results show that fuzzy adaptive PID controller is superior to the conventional PID controller in overshoot, response speed and adjusting time. And fuzzy adaptive PID controller has advantages of static and dynamic performance, intellectuality and robustness. It provides a powerfully theoretical guidance and basis for engineering practice of the followed flying-ashes-system. It is positively significant to further enhance the level of automation.

Key words: flying ashes, constant pressure conveying, fuzzy control, PID, MATLAB