Remaining useful life assessment via residual generator approach — A SOH virtual sensor concept

Based on analytical redundancy, specific set of residuals are designed to be sensitive to each component fault. The residual set may then represent as a measure of the loss of performance of the component in the system and thus, reflect the state of health of the component. The dynamic evolution of the residual can be considered as an image of the evolution of the component health, and can be modeled as the response of the component to the stress factors and the natural aging. The residual represents a degradation virtual sensor. Based on this prediction related to the various stress factors, the range of possible values of the remaining useful life (RUL) of the component can be predicted. The main contribution of the proposed paper is to present a new approach for RUL estimation based on a State Of Health degradation virtual sensor design. The range of values of the RUL can supply downstream applications for decision aids in maintenance or control. For illustration, the proposed approach was applied to the RUL prediction of actuators in a function of stress factors.