# Improved Safety Analysis Integration in a Systems Engineering Approach
## 7 Conclusions  
Nowadays, the safety of mechatronic systems represents a real challenge for safety experts, systems engineers, and designers, especially because of the increasing complexity of the systems. The main contribution of this work is to narrow the gap between MBSE and MBSA by integrating safety information in the systems engineering process. To reach this objective, a methodology which is composed of four steps is developed. The first two steps aim at improving the system's structure by proposing structural modifications. The structural modifications are deduced from the analysed information in the FMEA generated from the system description. Once the system's structure is updated, the system's behavior should be specified. For this reason, a redundancy profile that describes the behavior of the redundancy in the system is created. The redundancy profile is used with the system description to automatically generate a DFT via a generation algorithm. In the final step, the generated DFT is analyzed and a set of minimal cut sequences is obtained. Then, a state machine diagram is created using the obtained minimal cut sequences. This state machine is the first and only diagram, in this work, that describes the system's behavior in the system's model. The methodology is applied to an Electro-Mechanical Actuator case study, step by step, in order to validate the approach and to show the continuous improvement of system structure and behavior, thanks to preliminary safety analysis results.  
This work presents many advantages such as the increase of the competitiveness and the reduction of the safety analysis cost and time. In addition, it aims at enhancing the consistency between systems  
Figure 9: State machine of the EMA system.  
engineering models and safety artifacts by creating a link between them. However, the proposed methodology has some limits. For example, adding redundancy is not always an optimal solution with regard to the additional weight and cost, and the proposed methodology does not provide a comparison between a high reliability component and a redundant architecture. Also, during the generation of the DFT from the system model, the proposed algorithm cannot consider the redundancy of the external input of the system. For these reasons, in future works, the consistency between the system model and the safety analysis artifacts should be enhanced by proposing structural solutions other than redundancy. In addition, the redundancy profile should be improved to also consider the redundancy of the external inputs of the system. Finally, the result of the DFT analysis will be used, not only for the description of the system behavior but also to allow the updating of the system's model.  
Finally, we would like to thank the anonymous reviewers for their careful reading of our manuscript and their many insightful comments and suggestions.  
Conceived the idea, A.B., N.N., F.M., J.-Y.C. and A.M.; carried out the analytical derivations and numerical examples, A.B.; writing--original draft preparation, A.B.; writing--review and editing, A.B., N.N. and F.M.; Supervision, A.M. and J.-Y.C.  
The authors declare no conflict of interest.