The SEP-approach to evaluate large-scale intelligent freight transport systems

In this paper we present the SEP-approach, an approach to evaluate intelligent logistic systems and their control systems. The SEP-approach consists of four phases in which three types of models are used; simulation, emulation, and prototypes, of control systems and logistics resources. In the first phase a simulation model is made of the physical logistic processes. A second simulation model is made containing the logic of the control systems. This simulated control system is used to control different models of the logistic resources throughout the entire SEP-approach. In the second phase emulation models are made of the logistics resources. The emulated logistic resources are controlled by the simulated control system. In the third phase the simulated control system controls prototypes of logistics resources. In the fourth and final phase combinations of simulated, emulated, and prototype logistic resources are used simultaneously, all controlled by the simulated control system. This provides a ´rich´ test environment in which several aspects of the automated freight transport system can be studied, e.g. communication equipment, obstacle sensors, scheduling and routing of AGVs, and safety control systems. The SEP approach was successfully applied to evaluate automated guided vehicles and material handling stations for the underground Logistic System Schipol. The ULS Schipol is future large-scale automated logistic system in the Netherlands. By applying the SEP-approach the control systems and logistic resource designed for ULS Schipol were evaluated before implementation and commissioning.