The non-smoothness problem in disturbance observer design: A set-invariance-based adaptive fuzzy control method

This work removes the critical assumptions of continuity, differentiability, and state-independent boundedness, which are typical of compounded disturbances in disturbance observer-based adaptive designs. Crucial in removing such assumptions are a novel observer-based design with state-dependent gain in place of a constant one, and a novel...

A Novel Disturbance Observer Design for a Larger Class of Nonlinear Strict-Feedback Systems via Improved DSC Technique

A novel scheme for disturbance observer is designed for an extended class of strict-feedback nonlinear systems with possibly unbounded, non-smooth, and state-independent compounded disturbance. To overcome these problems in disturbance observer design, the typical slide mode differentiators are improved by introducing hyperbolic tangent...