비선형 동적시스템에 대한 비선형 미분 외란관측기를 이용한 유한시간 Dynamic Surface 제어기 설계

Abstract

This study proposes a finite-time dynamic surface control (DSC) combined with a nonlinear differentiator disturbance observer for nonlinear systems, in which dynamics are partially known. The nonlinear differentiator disturbance observer, virtual stabilizing controllers, and final controller were designed based on finite-time convergent theorem via the recursive steps in conventional DSC system. In conclusion, the study results show that the filtered output error due to the first-order filter in a conventional DSC, which is the source of controller design complexity and stability, can be bypassed; this is because stability is provided by a finite-time Lyapunov function comprised of newly defined variables instead of the tracking error variables used in conventional DSCs. Thus, the controller design procedure and stability analysis can be more intuitive than those of a conventional DSC. Another important study result is the design of a nonlinear differentiator disturbance observer for nonlinear systems to estimate uncertainty in finite-time. The study shows that very competitive results can be achieved using the proposed method, as shown by the simulation results for an articulated manipulator system.