**6. Conclusions**

In this paper, a method for optimizing the structure of a reluctance coil gun has been proposed. Kicking real soccer balls used at the RoboCup in the Middle Size League has been chosen as a case study. After having presented the principles of coil guns, a mechatronic model coupling mechanic, electromagnetic and electric ones has been proposed and implemented. Simulation results have been explained and discussed so that this optimization method can be easily reproduced in another application.

Results show that the output speed of the non-magnetic object propelled by the EML highly depends on the structure of the coil gun, the sequence for triggering it, the initial position of the iron plunger and the size of its non-magnetic extension. Among the results of this paper, we show that



**Table 5.** Ball launchers comparison including optimized launcher.

**Author Contributions:** Writing—original draft preparation, V.G.; writing—review and editing, T.S., S.M., H.G. and V.H.; visualization, V.B. and H.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** The APC was funded by [the Conseil Départemental du Var, France].

**Acknowledgments:** The authors would like to thank Pôle INPS of Toulon University and the Embedded Electronics Technology Platform of Toulon University named SMIoT (Scientific Microsystems for Internet of Things) [17] for its support in the achievement of this work, and the Conseil Départemental du Var, France, for funding this project.

**Conflicts of Interest:** The authors declare no conflict of interest.
