An Uncertain Operational Risk-Oriented Approach for Manufacturing System Functional Failure Prognosis

As the functional output of manufacturing systems, workpiece quality is the key objective for manufacturers to assure and enhance system health. Despite extensive studies, a key setback, i.e., lacking a feasible solution to handle the issue of uncertainty associated with 5M1E factors (i.e., Men, Machine, Material, Method, Measurement, and Environment) in the sense of risk modeling, still exists in the study of manufacturing system prognosis and health management (PHM) technologies. Correspondingly, an operational risk-oriented approach to predict functional failure for manufacturing systems is proposed. Based on a conceptual investigation of manufacturing system operational risk and functional failure in terms of 5M1E uncertainty, this study (i) applies a fuzzy Markov-based functional degradation model to characterize the uncertainties of the functional degradation process, and (ii) proposes the functional failure prognosis model considering explicit and implicit operational risk. As validation, an industrial case study based on an aero-engine cylinder head manufacturing system is conducted. The result demonstrates the effectiveness of the proposed method to predict the occurrence of functional failure and thereby eliminate operational risk.