Robust control for active damping of elastic gantry crane vibrations

One of the most significant structural dynamics problems of large gantry cranes are elastic vibrations in trolley travel direction. They put additional mechanical stresses on a crane construction and reduce crane operation performance. As these vibrations are mostly excited by trolley acceleration forces, they can be taken into account in the trolley motion control system. This article presents a robust control-based approach for active damping of the gantry crane elastic structural vibrations. The crane model with additional uncertainty models are derived using the finite element method (FEM). In order to achieve low order models that can be directly used for the control system design modal truncation as a model reduction technique is performed. The robust controller is then designed by the H-infinity-loopshaping design procedure evaluating the associated robustness margins. The proposed feedback strategy has been successfully verified on a laboratory gantry crane. (C) 2018 Elsevier Ltd. All rights reserved.