개선된 과도응답을 갖는 외란관측기 기반 강인한 백스테핑 제어

Abstract

This paper proposes a novel state space DOB (Disturbance Observer) to preserve nominal transient characteristics without inevitable deterioration in existing DOB-based control systems. The novel DOB is modified by introducing an additional auxiliary variable to guarantee Lyapunov stability of the DOB-based control system where the nominal system dynamics and the disturbance estimation error are considered simultaneously in a Lyapunov candidate function. It ensures that the states of DOB-based control system stay on the nominal responses and the disturbance estimation error converses to zero. By contrast, in existing DOB-based control, the DOB focuses only on the better disturbance estimation without considering inevitable estimation error in transient time which deteriorates the system response, therefore, nominal transient response cannot be preserved. The proposed DOB-based control is combined with backstepping control to cope with mismatched disturbances.