A framework for knowledge-based computer-integrated manufacturing

A description is given of an evolving framework for applying knowledge systems in a manufacturing environment. This framework consists of a set of object-oriented tools for modeling key elements of the environment (including processes, equipment, facilities, and operational procedures) and a complementary set of application-specific shells that use the models to perform common manufacturing tasks such as monitoring, diagnosis, control, simulation, and scheduling. The testbed used is the semiconductor fabrication line at Stanford´s Center for Integrated Systems. The key concept is a symbolic model of the manufacturing environment that can be created and maintained by manufacturing personnel. This model provides an open, unified framework that supports a variety of expert systems and integrates them with existing computer-integrated manufacturing (CIM) packages. The models provide a single consistent representation of the manufacturing domain that is shared by all applications. The shells embody methodologies, algorithms, and knowledge representations that are task-specific, but largely independent of the domain. Customized with domain-specific expertise, the shells will work for any environment that can be modeled