Real-time monitoring and diagnosis of a train door mechatronic system Laurent Cauffriez TEMPO-PSI EA4542 Université Valenciennes 59313, Valenciennes Cedex 9 laurent.cauffriez@univ-valenciennes.fr Sébastien Grondel IEMN-DOAE UMR CNRS 8520 Université Valenciennes 59313, Valenciennes Cedex 9 sebastien.grondel@univ-valenciennes.fr Abstract— For train manufacturers, a technical, economical, and societal key issue is the real-time monitoring and diagnosis of a train door in new generation of urban trains. Therefore, this paper proposes to deal with the modeling and diagnosis of a train door mechatronic system. For this purpose, the system is first detailed and shows a coupling between electrical and mechanical domains. As the modelling of such a mechatronic system needs a multidisciplinary and unified tool, the bond graph representation is chosen. Moreover, this model contains key components needed to reproduce the door movements and frictions. Thanks to this bond graph model, a global model-based FDI (Fault Detection and Isolation) is proposed for residual computations. Finally, the characterization of residuals for certain internal failures is investigated and the ability of the proposed diagnostic model to detect these failures and isolate some of them is demonstrated. The methodology employed is intended to be applied in a near future in real-time on the practical system. Keywords— Bond Graph; Train door; Mechatronic system; Fault detection and isolation;Residuals I. INTRODUCTION In a urban rolling stock, the door which is greatly stressed over its life cycle, is one of the most critical sub-systems from the standpoint of reliability because it is responsible for 30% to 40% of the failures during commercial use [1]-[2]. As part of a continual improvement process, the target of this paper is to model the well-functioning of the door in order to have a reference model and to propose a way to make a diagnosis of this latter in case of perturbations. A global model-based FDI (Fault Detection and Isolation) is therefore proposed. FDI principle (Fault Detection and Isolation) is currently the subject of numerous works and applications [3]-[8] and considerable progress has been made in all areas of this field. Although FDI studies have already been made for high-speed train [9], none has been processed on urban train doors. Indeed, the main differences result of a combination of factors such as a different technological choice for a design at a lower cost, a greater frequency of use and a poorer air tightness. It is therefore crucial to face this problem. For the modeling process, the Bond Graph formalism or the block diagram approach can be used as these formalisms make simpler the building of model and lead to a systematic writing of mathematical models. Moreover, in comparison with block diagram, the Bond Graph shows up explicitly the power flows or differential equations, and allows both causal and behavioural process analysis [10]-[11]. Therefore it is a graphical tool well adapted to represent power exchange between multi-physic systems [11]. Finally, as demonstrated in recent publications [12]-[17], structural and causal properties provided by this graphical presentation can be used for diagnosis, which is relevant for the chosen application. In the first part of the paper, the Bond Graph model for the chosen case study which concerns a train door in the field of railway industry is detailed. In the second part, residual computations are deduced from the bond graph model and exploited for influent factors sensibility analysis and for fault identification. Finally, the characterization of residuals for certain internal failures of train door is investigated and the ability of the proposed diagnostic model to detect these failures is demonstrated. II. SYSTEM GROUND MODEL A. Mechatronic system description The mechatronic system of Fig. 1 is made of five subsystems: the input voltage source U (Control signal), the Direct Current (DC) motor, the Pulley-Belt, the inverse Pitch Spindle, the load parts and the guide. Fig. 1. Description of the mechatronic system A positive (or a negative) value of the input voltage source U leads to a clockwise (anticlockwise) rotation of the “Pulley- Belt /inverse pitch spindle” subsystem resulting in a linear movement of load parts. Thus, both load parts are approaching