Step stress accelerated degradation process modeling and remaining useful life estimation

Abstract

Accelerated degradation process modeling and remaining useful life (RUL) estimation based on Accelerated degradation testing (ADT) are the essential parts of condition based maintenance and health management. Among the literature about the accelerated degradation process modeling, the current methods didn't consider the unit-to-unit variation of the equipment with the same type. Therefore, we present an accelerated degradation process modeling and RUL estimation method based on Wiener process. The Wiener process is used to model the degradation process of a single stress, and the drift coefficient is considered as a random variable to describe the unit-to-unit variation of different equipment. Based on the presented model, the information of reliability and RUL can be obtained. The parameter of the traditional acceleration model is considered as a random variable to describe the unit-to-unit variation of different equipment, and the traditional method turns out to be its special case. Through the step stress ADT data, a two-step maximum likelihood estimation method is presented to estimate the unknown parameters of the presented model. The results of the simulation about the laser degradation show that the presented method performs better than the traditional method and thus can be potentially applied in practice.