Tuning fuzzy feedback controllers using the circle criterion

摘要

This paper illustrates a method for tuning fuzzy feedbackcontrollers using the circle criterion. The method can be used fordesign, tuning at commissioning, or online adaptation of systemsconsisting of a fuzzy feedback controller and a process that can bemodeled as approximately linear or piecewise linear. The general tuningmethodology is developed by extending the concepts of gain and phasemargin from classical control. It is illustrated using a fuzzyproportional feedback controller with feedforward compensation. Thepaper shows that the key tuning parameter for stability is the ratio ofthe universe of discourse for the error input and the universe ofdiscourse for the control output