Prognostics in Custom-Build Electro-Hydraulic Variable-Speed Drive Applications

Developments in the field of condition monitoring for hydraulic applications have gained interest and a solid foundation of knowledge is largely established. The interest to further develop this into prognostics has increased, as the ability to predict outages and faults implies higher reliability and economical gain. This article presents a short review focusing primarily on the possibilities to enable prognostic control and identifies important features to enable prognostics. In addition, a definition of prognostic quality is proposed including aspects such as isolability, monitorability, cause, and predictability. This is followed by the modeling of an electro-hydraulic variable-speed drive, which is used to design an algorithm to predict maintenance and possible prognostic actions. This is done through monitoring different physical and artificial indicators utilizing the states measured in the system and using the information to predict future health conditions. Thus enabling the possibility to determine if a change in the control would be beneficial in order to extend the duration where the system can fulfill its design requirements. This creates a foundation for a possible methodology to obtain prognostic control for custom-build systems. The strategy proposal involves the identified methods and relates them to the covered topics in the review.