A Simple Remaining Useful Life Algorithm Using the Quadratic

Abstract

The goal of predictive maintenance (PdM) is to facilitate on-condition maintenance or reduce/eliminate unscheduled maintenance events. For critical systems such as aircraft,
PdM improves safety while increasing operational readiness. Aircraft operators can order the parts and ensure the correct skills and tools are available to avoid unplanned downtime.
An enabler for PdM is the need to estimate the remaining useful life (RUL). For RUL to be accurate, there needs to be an assessment of the current component health, a threshold
for when it is appropriate to do maintenance, and a degradation model. This model could be based on some physical processes, such as high-cycle fatigue failure.
However, often the exact fatigue process is unknown. In this paper, a quadratic RUL model is used to calculate RUL using a state estimator. The proposed process allows for model
validation of the RUL state estimator itself. This is demonstrated using a bearing fault, a gear fault, and oil debris example.