ENHANCEMENT OF DYNAMICAL CHARACTERISTICS OF A FUZZY CONTROL SYSTEM BY USING UNSTABLE SUBSYSTEM

A proposed approach to fuzzy controller synthesis is based on the usage of standard root-locus patterns of the characteristic polynomial. To improve a fuzzy system's transient behavior in the area of significant deviations, a method is proposed to form coefficients of a fuzzy controller that can move the roots of the characteristic polynomial in the right half-plane. The influence of the placing of either an even or odd root in the right half-plane on the transients of the synthesized fuzzy system is analysed and discussed. Furthermore, with the use of the third-order system, dynamic performance of the synthesized fuzzy system is improved by analyzing various special trajectories of the roots from the right to the left halfplane.