Sway and Disturbance Rejection Control for Varying Rope Tower Cranes Suffering from Friction and Unknown Payload Mass

Abstract Tower cranes are well-known underactuated systems, where the design of controllers for them with time-varying rope length was weak in the past because of their complex dynamic characteristic. The payload oscillation will become worse when the jib slew angle, the trolley position and the rope length are changed simultaneously. The proposed method is designed based on robust adaptive sliding mode control via tracking non-zero initial reference trajectories, in which, frictions and lumped disturbances in the crane system are eliminated, as well as unknown payload mass is effectively estimated online. Lyapunov technique is combined with LaSalle's invariance theorem to design controller and analyze stability. Various and strict simulations are applied, which validate the effectiveness and extreme robustness of the proposed method.