Control of a jib-type crane mounted on a flexible structure

This paper deals with modeling and control of a crane mounted on a tower-like flexible structure. A fast transfer of the load causes swaying of the load rope and vibration of the flexible structure. Our object is to control both the sway and the vibration by the inherent capability of the tower crane. We have already succeeded in realizing a decentralized control consisting of two individual controllers. This paper describes the design of a centralized control system considering coupling of between the up-and-down (boom luff) direction and the rotational direction. This is because there is a possibility that the control worsened due to the decentralized control system because it did not take into account coupling both directions. It is, therefore, necessary to compare it with a centralized control system and to examine the advantage of a decentralized control system precisely. From the results of the comparison of experiments and μ analysis, it is shown that the decentralized control system has almost the same performance and stability as the centralized one and that it is effective for the control of a tower crane.