Sliding Mode Control Approach for Double-Pendulum Rotary Cranes

Abstract

The dynamic performance analysis and controller design become more difficult, when the load sways present double-pendulum characteristics. Moreover, achieving both high-precision tracking control and load sway suppression are a more significant issue for crane systems. In order to solve the aforementioned problems, the nonlinear dynamics of rotary crane with double-pendulum effect is derived and decoupled using a disturbance observer for controller design. Then, a novel sliding mode controller with nonlinear sliding surface is presented. Unlike a traditional linear sliding surface, the nonlinear one can change the damping ratio of the closed-loop system from its initial low value to final high value. Numerical simulations validate that the proposed method has superior control performance.