Controller design for an overhead crane system with uncertainty

Overhead crane systems are widely used for material transportation in many industrial fields. However, undesired oscillation can always be found during the moving process, especially at the end location of the transport. The swing may extend the carrying time and cause safety problems. In order to achieve small swing angles, and also to incorporate the potential uncertainty property of the system, a robust controller has to be developed. Here, a controller, which combines a feedback linearization approach and a time delay control scheme, is chosen. The time delay control is applied to complete the feedback linearization for a nonlinear system under the influence of uncertainty. By suitable definition of system outputs, input/output de-coupling presents a direct relationship between the system outputs and inputs. Thus, robust cancellation of the uncertainty, and insertion of the designated dynamics can be accomplished. Encouraging control performance is shown in the results of a computer simulation.