DIRECT ADAPTIVE FUZZY PI SLIDING MODE CONTROL OF SYSTEMS WITH UNKNOWN BUT BOUNDED DISTURBANCES

An asymptotically stable direct adaptive fuzzy PI sliding modecontroller is proposed for a class of nonlinear uncertain systems. In contrast toother existing approaches of handling disturbances, the proposed approachdoes not require this bound to be known, only requiring that it exists.Moreover, a PI control structure is used to attenuate chattering. The approachis applied to stabilize an open-loop unstable nonlinear system as well asthe Duffing forced-oscillation chaotic nonlinear system amid significantdisturbances. Analysis of simulations reveals the effectiveness of the proposedmethod in terms of a significant reduction in chattering while maintainingasymptotic convergence.

Keywords:

Nonlinear control , Fuzzy logic , Sliding mode control , Uncertainty , External disturbances , Duffing forced-oscillation , Adaptive PI control