Comparison of some Classical PID and Fuzzy Logic Controllers




The proportional-integral-derivative (PID) controller is tuned to find its parameters values. Generally most of the tuning methods depend mainly on the experimental approach of open-loop unit step response. The controller parameters can be found if the system truly can be approximated by First Order Plus-Dead Time (FOPDT). The performance of most of them deteriorates as the ratio of approximated equivalent delay L to the overall time constant T changes. On the other hand fuzzy PID controller is not tuned through the same conventional tuning procedures. Itís constructed as a set of control rules and the control signal is directly deduced from the knowledge base and the fuzzy inference. Fuzzy controller parameters tuned by starting from the equivalent values obtained for optimum controller. The performances of different PID tuning techniques are simulated for different order systems and compared with fuzzy-PD+I controller. MATLAB simulation results show that Fuzzy PD+I have better performances over other conventional PID controllers.