Distributed parameter modeling of single-mast stacker crane structures

Abstract

This paper presents distributed parameter dynamical modeling capabilities of single-mast stacker crane structures. In the frame structure of stacker cranes due to external excitation or inertial forces undesirable structural vibrations may arise. These vibrations reduce the stability and positioning accuracy of stacker crane and causes increasing cycle time of storage/retrieval operation. Thus it is necessary to investigate of these vibrations. In this paper the dynamical behavior of single-mast stacker cranes is approximated by means of distributed parameter models. The first model is a cantilever beam model with uniform material and cross-sectional properties. This model is used to demonstrate fundamental properties of Euler-Bernoulli beam models. The second model is cantilever beam model with variable cross-sectional properties and lumped masses. The eigenfrequencies and mode shapes of this mast-model are determined by means transfer matrix method. In the third model the whole structure of single-mast stacker crane is modeled.