Fractional-Order Sliding Mode Control for a Container Crane System

In this paper, the problem of positioning and anti-swing control of four-rope container crane system was solved. At first, a nominal dynamics model of the four-rope container crane system is derived using the general Euler-Lagrange equations. Then, a fractional-order sliding mode control (FOSMC) method is proposed based on the fractional-order calculus theory and the sliding mode control. The designed control system ensures the asymptotic stability of the desired equilibrium points in finite time. Benefiting from the strong robustness of sliding mode control, uncertainties are not taken into account in modeling, which is verified by the simulation results. The simulation results show that the designed control system can not only achieve the control target quickly with high precision, but also suppress the system chattering. Therefore, the proposed control strategy is effective and feasible.