## 4 Discussion  
### ATV-Quad Rollover Tests  
In order to verify the successful operation of the complete test bench, some preliminary rollover tests with ATV were performed. Rollover tests with different configurations were developed, such as diverse directions for the overturn, as well as a variety of ATV models from the list in Table 2.  
Once all the electronic, hydraulic, and mechanical systems had been successfully set up and verified, a rollover test schedule was developed. This schedule was defined to include a large number of configurations, such as the mentioned below:  
1. Rollover tests were performed in each one of the four possible overturn directions.
2. Two dummies with different anthropometric characteristics were used.
3. The possibility for the ATV to include an empty or full fuel tank was also considered.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Manufacturer** & **Model** & **Mass (kg)** \\ \hline Yamaha & YFM 700R & 192 \\ Yamaha & Grizzly 660 & 272 \\ Honda & TRX 420 & 247 \\ \hline \hline \end{tabular}
\end{table}
Table 2: List of tested quad bikes.  
Figure 16: Components of the implemented electronic system.  
Additionally, some tests were developed where the dummy was fastened with a safety belt and without it.
* The safety device automatically deployable ROPS (AIR-ROPS) was installed in the ATV for some of the tests, and set up using diverse configurations, such as folded and inactive, unfolded and inactive, as well as folded and active.  
As a result of all the tests, and the subsequent analysis of the obtained data, it was possible to find a significant variation in the rollover angle for different vehicles, with diverse characteristics, and a variety of overturn conditions.  
Moreover, it has been proven that the test bench that has been designed, manufactured, and set up in this project, which allows one to perform rollover tests in any of the four feasible orientations, as well as using a variety of ATV models, since the position of the load cells, which support the wheels of the vehicle, can be adjusted to the particular tread and distance between axes of a given ATV.  
Furthermore, the perimeter fastening system of the platform was able to keep the vehicle on the bench during the non-destructive tests, as it can be seen in Figure 17.  
As a conclusion, it could be stated that the developed bench was validated for the development of rollover tests of the ATV-Quad in different configurations.  
The test bench required the addition of a mechanical element to avoid slippage of the vehicle, as the tilt angle increased in the development of the rollover tests. The friction coefficient between the tires and the perforated sheet on the mobile platform of the bench was not enough to prevent slippage of the vehicle at certain values of the tilt angle. This fact made it impossible to determine the rollover angle in these conditions.  
The solution to this problem, as it can be seen in Figure 18, consisted of two rubber blocks, 10 cm high, beside the wheels of the ATV that are closer to the axis of rotation of the mobile platform. These blocks were anchored to the perforated sheet. Shorter blocks, such as the ones shown in Figure 19, could not prevent the vehicle from moving over them, once a certain tilt angle was reached during the rollover tests; hence, in these conditions, the rollover angle could not be properly calculated.  
Figure 17: Manufactured rollover test bench with ATV-Quad fastened and dummy, ready to perform a test.