a case-based process planning system for machining of rotational parts英文精品课件.pdfVIP

Journal of Intelligent Manufacturing (1994) 5, 411-430 PROCASE: a case-based process planning system for machining of rotational parts HA0 YANG,l WEN F. LU1 and ALAN C. LIN2 ‘Department of Mechanical Engineering, University of Missouri-Rolla, Rolla, MO 65401, USA 2Department of Mechanical Engineering, National Taiwan Institute of Technology, Taipei, Taiwan Received March and accepted October 1993 This paper introduces a case-based process planning system PROCASE which generates new process routines through learning from existing process routines. In contrast to traditional rule-based systems, the process planning knowledge of the PROCASE is represented in terms of casesinstead of production rules. The planning basically comprises case retrieving and case adaptation rather than chaining applicable rules together to form process plans. The advantages are, first, the system is cheaper to build as it saves the expense of knowledge acquisition. Second, the system is able to advance its knowledge automatically through planning practice. Third, it is robust, because the reasoning is not based on pattern matching but similarity comparison. PROCASE has three modules: the retriever, the adapter and the simulator. It is supported by a feature-based representation scheme which naturally serves as the case indices for case retrieving and adaptation. The retriever uses a similarity metric to retrieve an old case which is the most similar case, among all old ones, to the new case. The adapter is then activated to adapt the process plan of the retrieved case to fit the needs for the new c