Remaining Useful Life Prediction for Multiple-Component Systems Based on a System-Level Performance Indicator

Most prognostics and health management publications focus on the development of algorithms to monitor and estimate the health condition of individual components. However, estimating the remaining useful life (RUL) of complex systems comprising multiple components is a more relevant topic for the industry. An accurate system-level RUL prediction can be used as a powerful decision support tool to help industry practitioners reduce operational costs and increase availability of systems. This paper presents a method to estimate the RUL of multiple-component systems based on health monitoring information regarding each component in the system under consideration. The proposed method relates the health factors of each component to its performance. Then, a system-level performance indicator is computed based on the performance of each component and a system architecture function that describes the relations among different components within the system. The system-level RUL is then estimated based on the extrapolation of the system-level performance indicator and a known failure threshold. In the proposed method, a system failure is not necessarily connected with a component failure. We present two case studies to illustrate the application of the proposed method: 1) a simplified aircraft hydraulic system containing multiple pumps; and 2) an aircraft air conditioning system containing different components.