Modeling and Adaptive Control for Tower Crane Systems with Varying Cable Lengths

Abstract

Tower cranes are highly underactuated nonlinear systems with five degrees-of-freedom (trolley displacement, jib angle, cable length, payload swing angles), and only three control inputs (one for the trolley driving, another for the jib driving, and another for the cable length varying). The three main control objectives of tower crane systems are driving the trolley and the jib to the desired position and desired angle, respectively, hoisting the cable length to the desired length while suppressing and eliminating the payload swing angles. Therefore, the model of tower crane systems with varying cable lengths is established, and on this basis, an adaptive control with payload swing suppression is proposed in this paper. Lyapunov method and LaSalle’s invariance theorem are illustrated to prove the stability of the closed system and the convergence of the system states. Simulation results are provided to validate the superior performance of the proposed control method.