Active Disturbance Rejection for a Three Degrees of Freedom Gyroscope

Abstract

This paper deals with the active disturbance rejection problem for a three degrees of freedom gyroscope. The goal is to design a robust tracking controller for the underactuated coordinate. A nonlinear model of the gyroscope, affected by matched and unmatched disturbances, is first obtained. Then, a high order sliding mode observer (HOSMO) estimates, theoretically in finite time, the disturbance signals. Such information is thus injected into the tracking controller to counteract the disturbances effect on the gyroscope dynamics. Stability of the closed-loop observer-controller system is analyzed through Lyapunov theory. Simulation results show the effectiveness of the proposed method.