Robust Control Based on Unknown Input Disturbance Observer for Fully Actuated Systems

In this paper, an unknown input disturbance observer is first designed for the single-order fully actuated systems with multiple disturbances. Due to the decoupling design, the observations of external disturbances are not affected by the discontinuous signals in the system. Furthermore, the sufficient and necessary condition for the existence of the observer is also given. Then a robust control scheme is proposed on the basis of full-actuation property. The controller not only utilizes the estimated values to compensate for the external disturbances, but also employs robust method to suppress the effect of discontinuous signals in the system, making the states of the closed-loop system ultimate boundness. An interconnected inverted pendulum simulation is provided to verify the effectiveness of the unknown input disturbance observer and the robust controller.