Section: New Results

Reliability

Participants : Yves Auffray, Gilles Celeux, Florence Ducros, Patrick Pamphile, Jana Kalawoun.

Since June 2015, in the framework of a CIFRE convention with Nexter, Florence Ducros has commenced a thesis on the modeling of aging of vehicles, supervised by Gilles Celeux and Patrick Pamphile. This thesis should lead to designing an efficient maintenance strategy according to vehicle use profiles. It will involve the estimation of mixtures and competing risk models in a highly censored setting.

Janan Kalawoun has defended her thesis supervised by Gilles Celeux, Patrick Pamphile and Maxime Montaru (CEA) on the estimation of the battery State of Charge (SoC). For vehicles powered by an electric motor, SoC estimation is essential to guarantee vehicle autonomy, as well as safe utilization. The aim is to create a reliable SoC model to closely fit battery dynamics in embedded applications (e.g., electric vehicles). The SoC is modeled by a switching Markov state-space model. Parameters are estimated by combining the EM algorithm and particle filter methods. The model is validated using real-world electric vehicle data. This model has been proved to be highly superior to a simple state space model. The optimal number of battery modes is then identified, using model selection criteria such as AIC and BIC, which has proved to be superior to cross-validation in this particular context.

In the framework of a study on the dispatch availability of Dassault Aviation business jets, Yves Auffray and Gilles Celeux have contributed to methodology aiming to discover the root causes of reliability flaws.