Design of Disturbance Observer Based Sliding Mode Control for Fuzzy Systems

In this paper, the disturbance observer (DO) based sliding mode control (SMC) for fuzzy system is proposed. Compared with conventional sliding mode control, this approach incorporates the disturbance estimates into the design of the sliding surface and sliding mode controllers. The new approach can deal with the problem of mismatched disturbance for fuzzy system effectively while those problems can't be solved by traditional sliding mode control. The disturbance observer, sliding surface and DO-based sliding mode controllers are proposed in the paper, respectively. An adaptive DO-based sliding mode controller is also established in order to deal with the problem about unknown upper norm bound of disturbance. Finally, the effectiveness of the new approach is illustrated by the ball-beam system.