Abstract
In this study, we investigate the modeling and vibration suppression control of single-mast stacker cranes for an automatic warehouse. Conventionally, in the design of a stacker crane, a two-stage analysis is often used in which a mechanism analysis is first performed assuming that all bodies are rigid bodies, and the obtained maximum load data is exported to a structural analysis. In addition, studies on vibration control often do not sufficiently consider the coupling between motion and vibration. In this study, the equations of motion of the mast, which is a flexible body, is expressed using the floating frame of reference formulation. In the formulation, the coupling between motion and vibration is strictly considered. However, in the floating frame of reference formulation, it is difficult to formulate sliding joints which causes a problem of a moving boundary condition. Therefore, we formulate the sliding joint constraint in which the carriage travels on the mast as an algebraic constraint including the dummy variable. Based on the derived flexible multibody dynamics model, we propose a residual vibration suppression method that actively utilizes the dynamic coupling between motion and vibration. Here, the reference trajectory of the cart and the carriage is represented by a B-spline curve, and a simple and practical algorithm for sequentially improving the trajectory by correcting the control points is formulated. It is confirmed that a large vibration suppression effect can be obtained by the proposed method through numerical simulation.
