Event management architecture for the monitoring and diagnosis of a fleet of trains: a case study

In recent years, more and more manufacturers and operators of fleets of mobile systems have been focusing their efforts on studying and developing condi-tional maintenance, monitoring, and diagnostic strategies to cope with an increasingly competitive, unstable, costly, and unpredictable environment. This paper proposes a case study concerning the application of a novel event management architecture, called EMH^2, to a fleet of trains. This EMH^2 architecture, which applies the holonic paradigm, aims to facilitate the monitoring and diagnosis of a fleet of mobile systems. It is based on a recursive decomposition of cooperative monitoring holons. The definition of a generic event modeling, called SurfEvent, is the second key element of the contribution. EMH^2 has been designed to be applicable to any kind of system or equipment up to fleet level. The edge computing paradigm has been adopted for implementation purpose. The EMH^2 architecture is designed to facilitate asynchronous and progressive onboard and off-board deployments. A real-world application of EMH^2 to a fleet of ten trains cur-rently in use, in collaboration with our industrial partner, Bombardier Transport, is presented. Three key perfor-mances indicators have been estimated by comparing EMH^2 with the current industrial situation. These indi-cators are (1) the number of fleet maintenance visits,(2) the time needed by a maintenance operator to investigate and diagnose, and (3) the time needed by the system to update data regarding the health status and monitoring of trains. Results obtained outperformed industrial expecta-tions. The paper finally discusses feedbacks from experi-ence and limitations of the work.

Speed profile optimization of catenary-free electric trains with lithium-ion batteries

Catenary-free operated electric trains, as one of the recent technologies in railway transportation, has opened a new field of research: speed profile optimization and energy optimal operation of catenary-free operated electric trains. A well-formulated solution for this problem should consider the characteristics of the energy storage device using validated models and methods. This paper discusses the consideration of the lithium-ion battery behavior in the problem of speed profile optimization of catenary-free operated electric trains. We combine the single mass point train model with an electrical battery model and apply a dynamic programming approach to minimize the charge taken from the battery during the catenary-free operation. The models and the method are validated and evaluated against experimental data gathered from the test runs of an actual battery-driven train tested in Essex, UK. The results show a significant potential in energy saving. Moreover, we show that the optimum speed profiles generated using our approach consume less charge from the battery compared to the previous approaches.

Numerical Investigation by the Finite Difference Method of the Laser Hardening Process Applied to AISI-4340

This paper presents a numerical and experimental analysis study of the temperature distribution in a cylindrical specimen heat treated by laser and quenched in ambient temperature. The cylinder studied is made of AISI-4340 steel and has a diameter of 14.5-mm and a length of 50-mm. The temperature distribution is discretized by using a three-dimensional numerical finite difference method. The temperature gradient of the transformation of the microstructure is generated by a laser source Nd-YAG 3.0-kW manipulated using a robotic arm programmed to control the movements of the laser source in space and in time. The experimental measurement of surface temperature and air temperature in the vicinity of the specimen allows us to determine the values of the absorption coefficient and the coefficient of heat transfer by convection, which are essential data for a precise numerical prediction of the case depth. Despite an unsteady dynamic regime at the level of convective and radiation heat losses, the analysis of the averaged results of the temperature sensors shows a consistency with the results of microhardness measurements. The feasibility and effectiveness of the proposed approach lead to an accurate and reliable mathematical model able to predict the temperature distribution in a cylindrical workpiece heat treated by laser.

Large-signal modeling of three-phase dual active bridge converters for electromagnetic transient analysis in DC grids

The three-phase dual active bridge(3 p-DAB)converter is widely considered in next-generation DC grid applications.As for traditional AC grids,the successful integration of power electronic converters in DC grids requires accurate time-domain system-level studies.As demonstrated in the existing literature,the development and efficient implementation of large-signal models of 3 pDAB converters are not trivial.In this paper,a generalized average model is developed,which enables system-level simulation of DC grids with 3 p-DAB converters in electromagnetic transient type(EMT-type)programs.The proposed model is rigorously compared with alternative modeling techniques:ideal-model,switching-function and state-space averaging.It is concluded that the generalized average model provides an optimal solution when accuracy of transient response,reduction in computation time,and wideband response factors are considered.