Load swing suppression in the 3-dimensional overhead crane via second-order sliding-modes

In this paper, an anti-swing control law, previously proposed for the 2-dimensional (2D, or planar) model of an overhead crane, is generalized to the 3-dimensional (3-D) case. The multi-input controller is based on the second-order sliding-mode approach. Thanks to specially designed sliding surfaces, explicitly depending on the load swing angles, zero steady position error and active load swing damping during the load transfer are attained by the proposed controller. The effectiveness of the proposed control method is validated by experimental results on a 3-dimensional laboratory crane prototype.