On-line self tuning fuzzy controller using intelligent membership function

A new design method is proposed for a fuzzy logic controller (FLC). By analyzing phase plane characteristics we can build and optimize the rule base of FLC. Variation of universe of discourse (UOD) can give coarse or fine control effects. With this variable UOD an adaptive gain tuning method is used to improve performance in transient and steady state. To show the improved performance of FLC and effectiveness of these methodologies, it is applied to design of attitude control system for a flexible spacecraft which has inherently a strong nonlinearities such as a hysteresis and a dead band.