A cooperative planning system for flexible assembly

An assembly planning system called COPLANNER is presented for integration of various tasks such as CAD, geometric modeling, geometric and physical reasoning, and assembly-process scheduling. The COPLANNER is organized by a blackboard system in which the plan coordinator, the geometric and physical reasoner, and the heuristic advisor interact. As an input to the system, an attributed liaison graph is used. It provides a unified representation of parts and their geometric and physical relations. An assembly plan is constructed based on the verification of the disassembly procedure through reasoning about geometric and physical interference and the extraction of preferred subassemblies. The generated plan is represented by a hierarchical partial-order graph, which not only provides the precedence relations among assembly operations but also presents the temporal and spatial parallelism for implementing distributed and cooperative assembly. Experiments show that the COPLANNER achieves desirable performance by generating an assembly plan which provides maximal parallelism and minimum assembly cost