DEVELOPMENT OF A GRAPHIC SIMULATION MODEL FOR DESIGN OF AUTOMATED GUIDED VEHICLE SYSTEMS (MATERIAL HANDLING, ANIMATED SIMULATION)

A graphic simulation model for non-simulation professionals to aid in the design of an automated guided vehicle system (AGVS) and to analyze its operational problems has been developed. The model is designed to display an AGV-based material handling system on a 2D CAD/CAM system, to manipulate simultaneously the movement of vehicles in the guidepath, and to obtain run-time statistics for a variety of applications. In particular, the model is based on the SIMAN simulation language with special features written to define AGVS guidepath layouts and operations. The application environment of the model is typically suited for the AGV-based push system consisting of several storage buffers for vehicles to pick up and drop off loads.;One of the main features of this approach is to integrate the graphic modeling, simulation program generator, animated visual interactive simulation, and presentation graphics techniques into a systematic methodology for the design of AGV systems. In addition, the user does not become involved in any programming activity, nor do any programs need to be debugged. Combined with computer graphics techniques, a simulation with animation allows the user to gain valuable insight into the transient and dynamic behavior of an AGVS. Accordingly, the user can obtain results more quickly and focus more attention on designing the best system and analyzing its performance.;Two vehicle dispatching strategies are presented: Vehicle Seeks Task (VST) and Task Searches Vehicle (TSV). The VST means that a released vehicle searches out tasks to perform from those waiting, and the TSV means that the arrival task seeks out available vehicles. In addition, three alternative policies for managing idle vehicles in an AGVS are defined. These policies are termed STAY, PARK, and CIRC.;Two case problems using the simulator are described. They provide validation of the Maxwell and Muckstadt model for determining the number of required vehicles, even though the traffic congestion and dynamic behavior of the system were considered in the simulation but not considered in their static model. The cases also demonstrate that the graphic simulator is an effective and useful design tool for evaluating an AGV-based transportation system. (Abstract shortened with permission of author.).