A Formal Planning Model for Case-Based Process Planning

Michael M. Marefat and John M. Britanik

Department of Electrical and Computer Engineering
University of Arizona
Tucson, Arizona 85721

Email: { marefat,britanik} @ece.arizona.edu

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Case-based reasoning provides an attractive paradigm for process planning as it combines the generative and variant approaches and improves the effectiveness of the planner by applying old experiences to solving new planning problems. Our research focuses on the development of a new case-based planning methodology that extends the capability and effectiveness of previous approaches. The planner, called CBPOP, is based on domain-independent partial-order planning, and provides a formal approach to case-based process planning. In addition, the planner has the capability to use pieces of multiple old plans in the process of constructing a new plan, providing more effective utilization of the planner's previous experiences. CBPOP generates plans for the features of a part (eg: slots, pockets, holes, etc.) independently. These feature plans are then merged using a hierarchical plan merging mechanism we have developed. The objective of this plan merging is to generate a global process plan for the part while minimizing the number of fixture and tool changes.