Real-Time Work-in-Progress Management for Ubiquitous Manufacturing Environment

Recent developments in wireless technologies have created opportunities for developing next-generation manufacturing systems (NGMS) with real-time traceability, visibility and interoperability in shop-floor planning, execution and control. This chapter proposes a referenced infrastructure of Ubiquitous Manufacturing (UM). Under this infrastructure, a Smart Gateway and a real-time work-in-progress management system (WIPMS) based on smart objects such as RFID/Auto-ID devices and web service technologies are designed to manage and control the real-time materials flow and information flow to improve the optimal planning and control of the entire shop-floor. During manufacturing execution stage, they can provide operators and supervisors with real-time status and information of current manufacturing environment. It follows a simple but effective principle: what you see is what you do and what you do is what you see. Production disturbances could thus be detected and fed back to decision makers for implementing closed-loop shop-floor control. For manufacturing information sharing and integration, a work-in-progress markup language (wipML) is used to establish the information model and schemas of WIP based on some important standards such as ISA 95 and B2MML. Then, the real-time manufacturing information can be effectively encapsulated, shared and exchanged between Smart Gateways, WIPA and heterogeneous enterprise information systems (EISs). Finally, the presented framework is demonstrated through a near real-life simplified shop-floor that consists of typical manufacturing objects.