## 3 Application of the Design Approach to the Definition of the Innovative Test Rig
### Design of the Subsystem to Perform the Global Static Stability Tests (i.e., the 'Turntable')
In this case, for example, adopting the kinematic inversion principle (see Section 3.4), instead of having a stationary vehicle placed on a device capable of performing more or less complex movements (tilting platform with at least two degrees of freedom, corresponding to two hinges), the following solution could be preferable (Figure 23):  
* the support structure has only one dof (i.e., the possibility of inclining the supporting structure in a unique direction, as in the conventional test rigs for investigating the static lateral overturning angle);
* the vehicle is given a second dof or, rather, this second dof is enacted by the part of the support immediately below the vehicle; this could be achieved by positioning the vehicle on a rotating platform ('turntable') included within the 'tiltable' structure. 3.2 Preliminary Analysis and Selection of the Different Implementing Possibilities for the Inclination Mechanism (\(\rightarrow\) Step 1.d)  
Similarly to what has been done for the global inclination mechanism, the pros-and-cons of each above-illustrated solution to perform the global static stability tests are collected in the following Table 4 for proper evaluation. Figure 23: Exemplification of an innovative platform for executing static stability tests having the possibility of inclination and a rotating component (in yellow) in the tiltable plane; the hinges are represented in black, the initial positions are indicated within brackets; all possible movements are indicated by the red arrows; the blue arrow indicates the maximum sloping direction; the rectangle positioned in the middle of the rotating component represents the support polygon of a vehicle in test (its longitudinal axis is hatched). Figure 22: Exemplification of a platform for executing static stability tests having two simultaneous possibilities of inclination; the hinges are represented in black, the initial positions are indicated within brackets; all possible movements are indicated by the red arrows; the blue arrow indicates the maximum sloping direction; the rectangle positioned in the middle of the ‘tiltable’ platform represents the support polygon of a vehicle in test. Note that there is an additional, intermediate frame (in yellow) that is the support for the second inclination mechanism. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Subsystem** & **Solution** & **Pros** & **Cons** \\ \hline Platform for executing & \begin{tabular}{c} Possibility to carry out \\ global stability tests \\ without any need to \\ reposition the vehicle on \\ its surface to complete \\ component in the \\ ’tiltable’ plane (the \\ so-called ’turntable’) & \
\begin{tabular}{c} Possibility to carry out \\ global stability tests \\ without any need to \\ reposition the vehicle on \\ its surface to complete \\ the experimental \\ investigation; the \\ inclination mechanism is \\ only one \\ \end{tabular} &
\begin{tabular}{c} Need to have a rotating \\ component sized to \\ support an agricultural \\ vehicle; need to have a \\ support structure for the \\ rotating component \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Advantages (’pros’) and disadvantages (’cons’) of the solutions proposed to realize a mechanism to perform the global static stability tests; scheme references are the same as in Figures 21–23.