Towards a general condition based maintenance model for a stochastic dynamic system

Rotating machinery prognostics: State of the art, challenges and opportunities

“…Therefore, he modelled a conditional residual time distribution to estimate the residual life distribution of rolling element bearings based on the stochastic filtering theory [65]. All the test bearings were initially assumed to follow the Weibull delay time distribution modelled, and as more CM information became available, the distribution was updated.…”

Plant residual time modelling based on observed variables in oil samples

“…This development of the model differs from similar previous work (Wang and Christer, 2000;Wang, 2002Wang, , 2003Wang and Zhang, 2005) mainly in the treatment of observed variables, but also with some new extensions. The modelling of internal variables and their relationships with the residual time is similar to that in Wang and Christer (2000) and Wang (2002Wang ( , 2003, but is developed using a new setup with a constant variance property as required.…”

“…The modelling of internal variables and their relationships with the residual time is similar to that in Wang and Christer (2000) and Wang (2002Wang ( , 2003, but is developed using a new setup with a constant variance property as required. Wang and Zhang (2005), Jardine et al (1989), Makis et al (2006), used all observed variables in oil samples as external but we separated them as explained earlier.…”

“…It can be shown that if maintenance actions were taken into account (Wang and Christer, 2000), depending whether the actions were treated deterministic or random, a general filtering system equation must be developed, which is beyond the scope of this paper.…”

“…However, the accurate prediction of the residual time can be very helpful for planning appropriate maintenance and replacement schedules in a cost-effective way (Wang and Christer, 2000). In the case of an oil analysis programme, the moment lubricant oil enters an operating plant such as an engine, it begins to deteriorate as it becomes contaminated with wear metal debris, oxidation by-products and external substances such as water, dirt and/or process material.…”