## 3 Results and Discussion
### Possible Realization of the Described Test Rig  
From a structural point of view, it is possible to simplify the structure of the test rig presented in the previous paragraphs by reducing the support surface to the quadrants only (Figure 23a-c). The final result of this design process, visible in Figure 23d,e, is currently under development and will be installed within the \"Laboratory for Agroforestry Innovations\" at the NOI Techpark in Bolzano (Italy).  
Despite the conceptual simplification of the structure, which has reduced it to just the quadrants (each one having the following dimensions: 2.10 m \(\times\) 3.15 m), it was decided to position the tilt hinges at the center of the supporting structure. This design choice allows the installation to tilt up to 60\({}^{\circ}\), limit the maximum elevation of the platform and hold the vehicle in test in a pit in case of a failure of the vehicle fixture system. Indeed this layout requires the excavation of a 3.70-m-depth pit to house the main column and allow the structure to incline. The pit occupies more than 100 m\({}^{2}\) on the laboratory floor (dimensions 11.00 m \(\times\) 9.50 m), i.e., an extension wider than the top surface of the turntable (equal to 26.46 m\({}^{2}\)), so as not to interfere with it during rotations. CAD estimates indicate a total mass for the platform of about 25,000 kg with a nominal load-bearing capacity of 10,000 kg for the bearing structure (value corresponding to the maximum weight of vehicles that can be safely tested by the rig with inclinations up to 60\({}^{\circ}\)); the safety factor is 1.5, meaning that the structure can withstand up to a weight force of 15,000 kg\({}_{\text{f}}\) before collapsing. The maximum load on a single quadrant is instead set at 5000 kg\({}_{\text{f}}\), thinking to a condition of incipient rollover for a 10,000-kg vehicle, i.e., a scenario characterized by the total weight supported by only two wheels/quadrants. Thanks to its dimensions, this test installation is capable of testing vehicles of different sizes, both with a conventional architecture (i.e., with front steering wheels) and with a central steering joint (articulated machines), possibly also in a steering configuration.  
The quadrants surface is made with a rigid and simple-to-be-serviced embossed metal plate with a standard pattern, to have a high-grip support surface that can be easily found and used also in other similar possible future test installations (this is the premise to have normed scenarios hence allowing to perform a comparison of test outputs even if coming from different test stations). For safety reasons, each quadrant is also equipped with steel ropes to be used to secure the hub of each wheel supported  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & & \multicolumn{4}{c}{**Wheels Loads (N)**} & \multicolumn{4}{c}{**Wheels Load Distribution (\%)**} \\ \cline{3-10}  & & \(W_{\text{FR}}\) & \(W_{\text{FL}}\) & \(W_{\text{RR}}\) & \(W_{\text{RL}}\) & \(W_{\text{FR},\%}\) & \(W_{\text{FL},\%}\) & \(W_{\text{RR},\%}\) & \(W_{\text{RL},\%}\) \\ \hline \multirow{2}{*}{20.00} & min & 3182 & 3338 & 4601 & 4843 & 9.0 & 9.5 & 13.1 & 13.8 \\ \cline{2-10}  & max & 12,446 & 12,669 & 16,618 & 16,899 & 35.4 & 36.0 & 47.2 & 48.0 \\ \hline \multirow{2}{*}{33.95} & min & 0 & 163 & 0 & 228 & 0.0 & 0.5 & 0.0 & 0.7 \\ \cline{2-10}  & max & 15,869 & 16,102 & 20,394 & 20,686 & 51.1 & 51.8 & 65.6 & 66.6 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Maximum and minimum values recorded during a complete rotation of the turntable for \(\alpha=20.00^{\circ}\) and \(\alpha=33.95^{\circ}\) (incipient rollover).  
by that quadrant (see Figure 23d). The anchor ropes will only tension when the tipping condition for that vehicle is reached.