Delayed Position-Feedback Controller for the Reduction of Payload Pendulations of Rotary Cranes

Abstract

In this paper, we show that, in rotary cranes, it is possible to reduce payload pendulations significantly by controlling the crane's translational and rotational degrees of freedom. Such a control can be achieved with the heavy equipment that is already part of the crane, so that retrofitting existing cranes with such a controller would require little effort. Moreover, the control is superimposed transparently on the commands of the operator. The successful control strategy is based on delayed position feedback of the payload's in-plane and out-of-plane motions. Its effectiveness is demonstrated with a fully nonlinear three-dimensional computer simulation and with an experiment on a scaled model of a rotary crane. The results demonstrate that the pendulations can be significantly reduced, and therefore the rate of operation can be greatly increased. The effectiveness of the controller is demonstrated for both rotary and gantry modes of operation.