Framework for a flexible, real-time controller for automated material transport systems

Abstract

The functions of a material transport system (MTS) in a manufacturing facility is to move raw materials, work-in-process, finished parts, tools and supplies from one location to another in an efficient and timely manner. This thesis presents a framework for a flexible, real-time controller for automated material transport systems. The material transport controller is designed to control material transport systems having automated material transport equipment, which have a dedicated controller capable of accepting transportation tasks. The proposed MTC can be used to control different MTS and therefore, the material transport system layout must be represented so that the layout information can be used by the material transport controller to control the MTS. A layout representation schema is proposed for describing the attributes of the material transport system layout. The material transport controller (MTC) is flexible because any dispatching, planning or scheduling algorithm can be "plugged-in" and implemented. The dispatching, plann' ing and scheduling algorithms should be developed taking the layout representation into consideration. Hence, the same algorithm can also be used to run different material transport systems. Another feature of this MTC is that different control configurations can be easily implemented. A control configuration is the sequence in which the dispatching, route planning and scheduling functions are invoked by the MTC. The proposed material transport controller is thus flexible in nature and can be used to implement different strategies for dispatching, planning and scheduling without having to rebuild the entire controller. Therefore, the development time and cost of creating a new material transport controller is significantly reduced.