Modified Smith Input-Shaper Crane-Controller for Position Control and Sway Reduction

In this paper, the control structure for a crane system is proposed. It is designed to achieve fast cargo transfer with minimum cargo sway. The proposed control structure reduces the cargo sway generated by the position controller, which accelerates and decelerates cargo to transfer it with minimum time from the start to the desired location. A comparison between results achieved by simulation and experiments in the laboratory is given. Each segment of the proposed control structure is analyzed, and reasons for their use in this control structure are explained. The laboratory model’s parameters are identified to parameterize the position controller and sway-reduction control structure. This control structure uses only the cargo’s position feedback because the main reason for cargo sway, for which a sway reduction is needed, is crane movement, which is controlled by the position controller. Other control structures use two types of feedback, while this proposed control structure uses only one. Because of this, it is also economical.