*2.4. Mechanical Model*

The mechanical model has been defined following the coil gun structure described in [11]. However, our kicking system is very similar in terms of dimensions and weight to that one which serves as a reference design for most RoboCup teams. Consequently, this model will be reusable for other teams, and can be adapted for other use cases by changing the content of some blocks according to the chosen mechanical design. However, changing parameters of the coil requires to simulate again the electromagnetic part, as force depends on coil gun geometry, current and plunger position.

As for the electrical model, an analytical calculation of the force is not possible. The finite elements model using *FEMM 4.2* shows that force varies in our case study from −1900 N to 19,000 N for the same coil depending on the plunger position and on the coil current (Figure 16). Discrete values of the force are calculated for positions of the plunger (Figure 15) varying from *x* = −100 mm to 60 mm by increment of 5 mm, and for coil currents varying from 1 A to 200 A by increments of 50 A.

It is important to note that:


**Figure 16.** Variation of the force on the plunger depending on its position and the coil current.
