An autonomous decentralized system architecture and techniques for on-line development and maintenance

The recent movement to customer-driven production has resulted in the needs for flexible production systems, that are compatible with the localization, the concurrency, and the cooperation of development and maintenance processes under on-line operation. This paper proposes an architecture and techniques to make on-line development possible. This architecture enables the on-line development of frequently reconstructed systems and is based on the Autonomous Decentralized System concept, which is tolerant of heterogeneous subsystems in a system. Techniques for on-line development are described, with which development and maintenance subsystems cooperate with on-line subsystems, share mutual data and on-line data synthetically, and are prevented from disturbing on-line operation. These features make it possible to develop or maintain systems locally and quickly even when specifications of the whole system are ambiguous. The proposed architecture and techniques have been applied to many industrial production systems and their effectiveness has been verified in a steel production system.