An HMS Operational Model

This chapter investigates the function block-based Holonic Manufacturing System (HMS/FB) architecture and specifies the HMS operational model by blending concepts from the HMS/FB architecture and Co-operating Knowledge Based Systems (CKBS). The HMS operational model addresses holonic interaction issues viz. negotiation and co-operation, during task distribution, scheduling, execution and execution control. We envisage two levels of sophistication of the HMS operational model: (1) a basic operational model, supporting only the minimum functionality of the HMS, and (2) a fault-tolerant operational model, supporting advanced operational strategies such as fault tolerance. We have used motor assembly testbed requirements, provided by the Japanese HMS consortium to illustrate the basic operational model, and we have generalised two holonic shopfloor layouts, namely, the DaimlerChrysler’s engine assembly testbed and Rockwell Automation’s proposed simulation testbed for elaborating the fault-tolerant operational model. Although the manufacturing requirements used for this study are necessarily abstract, the ideas discussed in this chapter can provide a useful abstract foundation for many HMS implementations.