Controller design for large time-delay objects

The large time-delay objects widely exist in industry process and they are difficult to be controlled especially when control coefficient is bigger than 0.5, a hybrid control method with on-line parameters adjustment is adopted to maintain the pressed air pressure of a coal mine at a const value. The Fuzzy-PID controller discussed here has a one-order feedback loop which can decrease lag time, for the more, it can adjust PID parameters online with Fuzzy logic according to the pressure value and its changing rate. simulation and practical running indicate that its tracking precision and converging speed are high, ability of coping with model uncertainty is strong and its realization is easy.