Flatness based active disturbance rejection control for cart inverted pendulum and experimental study

A flatness based robust active disturbance rejection control technique scheme is proposed for the problem of stabilization and tracking control of a special underactuated, non-feedback linearizable mechanical system known as the cart inverted pendulum. The differential parametrization on the basis of linearizing the system around an arbitrary equilibrium decouples the underactuated systems into two lower systems, leading to two lower state observers, based on which the active disturbance rejection control is derived. An observer based active disturbance rejection controller without considering the decoupling property is also designed to be compared. Simulation and experimental results on the stabilization of the pendulum angle and tracking control of the cart position are presented to show the advantages of the combination of the flatness, the decoupling property and the active disturbance rejection control technique.