Zero-accident Agile Manufacturing Systems through Subsumptive Fault-tolerance

Traditional methods of achieving manufacturing system safety exploit the highly repetitive nature of traditional manufacturing operations. With agile manufacturing systems, the interactions between machinery and personnel (operator, set-up, and maintenance) become less predictable. The smaller batches and more varied product drive hardware and software designs that are difficult to model and impossible (for all intents and purposes) to test exhaustively. Subsumptive fault-tolerance develops a multi-layered architecture where each successive layer incorporates the fault tolerance provided by all layers beneath. This approach assumes that faults will eventually occur in complex systems and attempts to trap these faults before they become safety concerns. Faults in manufacturing systems may include: unpredictable personnel behavior, software bugs, hardware flaws, and external events (such as power outages). The multi-layered subsumptive architecture should protect personnel even in the presence of multiple faults.