Stability analysis of systems with parameter uncertainties under fuzzy logic control

Systems with parameter uncertainties are difficult to control. We propose a combined controller approach to tackle this problem. This approach involves designs of different controllers for different operation points. Then a fuzzy logic controller (FLC) is used to schedule these controllers according to the plant parameters. This FLC is different from the common FLCs in that plant parameters are used as the input variables in the premises of the fuzzy rules. Hence this FLC can tackle a large parameter change during operation. The resulting FLC will not only display good robustness but also lead to a stable closed-loop system. The stability will be proved by applying a new stability analysis method.