Control of a flexible assembly cell is a complex task due to its multi-operation nature and to its dynamically changing states resulting in numerous alternatives. Usually, cell control is done hierarchically and encompasses operation scheduling and real-time control activities.
This paper discusses the design of a knowledge-based scheduling system for a flexible assembly cell. The system integrates disruptions and can be connected to a real-time cell controller. It is composed of a static database, a dynamic database, expert modules and is driven by an asynchronous clock The knowledge is hierarchically organized in the distinct expert modules, each standing for a decision level. The scheduler is characterized by a scheduling in advance methodology, and this capability is to he used on- or off-line.