Nonlinear control of an overhead crane via the saturating control approach of Teel

This paper presents a new control strategy for the horizontal position control of a two degree-of-freedom overhead crane. The approach transforms the underactuated crane dynamics into a form similar to the well known ball-and-beam dynamics. A controller is then developed based on the work of Teel for the transformed dynamics using a saturation control design technique. The control approach is based on a crane model which includes the typically neglected, higher-order nonlinearities. The resulting controller provides for asymptotic positioning of the crane payload from a large set of initial conditions. Experimental trials demonstrate the performance of the proposed controller while a computer simulation is used to suggest the benefit of the proposed saturation controller over a standard linear controller.