Fuzzy-PID Controller And Its Application On Constant Temperature System

Fuzzy PID, whose research has been acquired abundant achievements, is one of the most active field of intelligent automatic control. Multiple compound control employs widely in the process control among fuzzy PID, Fuzzy-PID control, which has been choosed as the subject of this paper, is one of these technology. They work in the different rang of error value and switch from one regulator to another based on error value., In other words, double mode control combines the advantages of fuzzy logic control (FLC) and conventional linear PID controller guarantee zero-error in the steady state. As such, they have a high quality control performance.Common double mode control is switched based on predeterminate error value by program. Therefore, how to select suitable error value and existing disturbance during switching are unavoidable defects. However, a new fuzzy switching based on fuzzy rules proposed in this thesis can dodge those shortages. This algorithm is very simple, and control performances, i.e., robustness, the capacity of the anti-interference, tracking, are better than common double mode control.Based on the above, the application on temperature controlling of the Fuzzy-PID double mode controller switch based on fuzzy rules is studied. The Simulink's emulator indicate that the controller have a good performance both on stabilizing time and system steadfastness. In order to make this controller being more practical, I did some work to write the VHDL programs for the controller and hope this will be helpful to the next research work.