In this paper an approach to the design of conveyor systems and particular the design of tracks suited for luggage handling systems in airports is presented. The considered system consists of a closed track with a closed loop of carts carrying the luggage for different flight destinations. The track is a 3 dimensional structure assembled of both straight and arc segments as well as level changes of different kinds. The loop of carts is considered as a multibody system including joint flexibility and the stationary track as a guiding frame. While the track forms a continuous line the closed loop of carts approximates the same geometry in a piecewise linear discretized form. Due to geometric effects caused by the use of straight and arc segments the required length of the discretized line varies in order to remain closed when the system is in service. Since the length variation is one of the principal factors in the resulting load spectrum for the carts in the system the aim of the presented work is to reduce this length variation and thereby reduce the fatigue load on the carts.
The length variation is split into two: a global variation of the length of the entire track and a local variation of the length of smaller parts composed of two curves and one straight segment or two straight segments and one curve. An optimization problem is formulated with a view to minimize the fatigue load on the carts using the radii of the arcs and the length of the straight segments as design variables. The design problem is subjected to kinematic constraints ensuring that both the carts and the tracks remain as closed loops.
The approach is applied to an existing design, and both the original design and the optimized design are implemented in an experimentally verified time domain simulation model of the entire system and the load spectra for the designs are compared.