Modeling and Control of a Rotary Crane with a Hydraulic Cylinder

In this paper, we first derive a dynamical model of a rotary crane whose boom angle is controlled by a hydraulic cylinder. On the basis of the dynamical model, we propose an open-loop plus feedback control scheme. The crane makes three kinds of motion (rotation, load hoisting, and boom hoisting) simultaneously. The goal is to transfer a load to a desired place in such a way that at the end of transfer the swing of the load decays as quickly as possible. We first apply an openloop control input to the system such that the state of the system can be transferred to a neighborhood of the equilibrium state. Then we apply a feedback control signal so that the state of the system approaches the equilibrium state as quickly as possible. The results of computer simulation prove that the open-loop plus feedback control scheme works well.