Active Disturbance Rejection Method for Positioning and Payload Swing Suppression of Tower Cranes

Tower cranes, as key lifting equipment in construction and ports, face challenges in precise positioning and payload anti-sway control due to their underactuation, nonlinearity and strong coupling characteristics. To address those challenges, this paper proposes a controller method combining active disturbance rejection control and differential flatness theory. Firstly, the differential flatness of the 4°-of-freedom(4-DOF) tower crane system was proved. The system state was expressed as the algebraic combination of the flat output and its finite-order derivatives, thereby transforming the control problem into a tracking problem of the flat output.Secondly, a tracking differential is designed to arrange the transition process to suppress overshoot, and an extended state observer is utilized to estimate the total disturbance of the system and higher-order state quantities, achieving feedforward compensation and state reconstruction. Finally, the effectiveness of the proposed method is verified through simulation. The results show that this method can effectively suppress the load swing while achieving precise positioning of the jib and the trolley.