A Gemoetrical Approach to Computing Expected Cycle Times for Class-Based Storage Layouts in AS/RS

An exact, geometry-based analytical model is presented that can be used to compute the expected cycle time for a storage/retrieval (S/R) machine, executing single-commands, dual-commands, or both, in a rack structure that has been laid out in pre-specified storage zones for classes of goods.The rack may be either square-in-time or non-square-in-time.The approach is intuitively appealing, and it does not assume any certain layout shape, such as traditional "L-shaped" class layouts.The model has been coded in Turbo Pascal, and can be used by designers as a tool for quickly evaluating alternative layout configurations with respect to expected S/R cycle time in an AS/RS, and thereby the throughput of an automated warehouse over time.This model has been successfully applied in a major manufacturing plant in Europe to evaluate reconfigurations of their rack storage layouts over the past five years.