Structural research of fuzzy PID controllers

While there exist many conventional methods for PID auto-tuning, This paper will strictly focus on providing the basic ideas on how you would construct a fuzzy PID auto-tuner. Simple fuzzy rules maybe used. Conventional gain scheduling involves using extra information from the plant, environment, or user to tune (via "schedules") the gains of a controller. These control designs provide a set of gains for the controller at each operating condition. A gain schedule is simply an interpolator that takes as inputs the operating condition and provides values of the gains as its outputs. This paper analyses the structure of an important class of two dimensional fuzzy controllers on the other hand. We have established conditions, some are necessary and sufficient while others are sufficient, under which this class of fuzzy controllers are structurally equivalent to the nonlinear PI or PD (PID) controllers with variable gains. The some fuzzy controllers are actually nonlinear PI, PD controllers with variable gains that can outperform linear counterparts.