Time domain simulation of large-scale material handling chains using an unconstrained formulation

Abstract

This article presents a dynamic time domain simulation model of loop-sortation systems. Loop-sortation systems for sortation of medium-size items are designed as a closed chain of carts guided in a closed loop track with a view to meet customers’ requirements of capacity and space available. Loop-sortation systems are complex mechatronic systems which require the use of simulation models in order to analyse, predict, and improve the dynamic performance in a cost efficient way. The model utilizes theory for unconstrained rigid multibody dynamics where contact between carts and between cart and track are modelled through the use of force elements. To determine contact between the track and the chain of carts, a rapid and robust contact search formulation has been developed and implemented in the model. Comparisons of main forces of the chain model are made with experimental measurements on three different test layouts. Verification results show that the normalized root mean square deviations are generally less than 10 per cent.