# On the Influence of Suspension Geometry on Steering Feedback
## 3 Results  
From here, different suspension geometries have been proposed with the aim of possibly restoring a stable and intuitive steering response regardless of the disequilibrium induced by the torque vectoring at the front, while maintaining at least the same overall steering ratio, and without claiming to achieve a definitive configuration. As a matter of fact, the refinement of the self-aligning properties given by the combination of tyre characteristics and steering geometry would certainly require more insight and fine tuning. Additionally, the compatibility with the design of the wheel group itself would require further evaluation, where the wheel group is composed by the wheel, the upright/brake assembly, the CV joint/driveshaft assembly, etc. The second variation (EB1) was designed to reduce the kingpin offset (KO) (Figure 16 and Table 2). After the same sine steer sweep test, the steering wheel torque of EB1 is shown in blue in Figure 17. Apart from a small phase shift at low frequency, the steering effort is very similar to the reference case. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Name** & **Caster [deg]** & **Kingpin [deg]** & **SR [mm]** & **CT [mm]** & **KO [mm]** & **Sa/Wa [deg/deg]** \\ \hline Original & 10.2 & 14.2 & 16.1 & 29.0 & 102 & 15.7 \\ EB0 & 5 & 3.7 & 29.2 & 12.5 & 51.4 & 15.5 \\ EB1 & 5.3 & 2.1 & \(-\)1.2 & 30.2 & 11.4 & 15.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: New EB1 suspension compared with the previous ones. Figure 16: Schematic front view (yz plane) of the EB1 suspension, KO has been reduced to almost zero. Figure 17: The EB1 sine steer (blue) compared with TV original (red) and passive vehicle (green). At this point, further variations were designed with a small, negative KO (\(-5.6\) mm, EB2, Figure 18) and with a very large negative one (\(-48.9\) mm, EB3, Figure 19 and Table 3). EB3 in particular features a larger amplitude in terms of self-aligning torque, as shown in Figure 20. Again, although this is a self-aligning torque, in the simulator, the amplitude reveals itself to be too much of an effort, hence it is not desirable and calls for very small values of KO, which in turn is in agreement with vehicle dynamics experience and theory. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Name** & **Caster [deg]** & **Kingpin [deg]** & **SR [mm]** & **CT [mm]** & **KO [mm]** & **Sa/Wa [deg/deg]** \\ \hline Original & 10.2 & 14.2 & 16.1 & 29.0 & 102 & 15.7 \\ EB0 & 5 & 3.7 & 29.2 & 12.5 & 51.4 & 15.5 \\ EB1 & 5.3 & 2.1 & \(-1.2\) & 30.2 & 11.4 & 15.0 \\ EB2 & 3.9 & \(-7.8\) & 40.8 & 16.4 & \(-5.6\) & 15.3 \\ EB3 & 4.8 & \(-8.1\) & \(-0.3\) & 19.0 & \(-48.5\) & 15.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: New EB2 and EB3 suspensions compared with the previous ones. Figure 19: Schematic front view (yz plane) of the EB3 suspension, with large and negative KO. For the sake of completeness, in order to verify the global performance of the vehicle, additional offline simulations were carried out on a lap of the Hockenheim short track (Figure 21), a circuit featuring either slow and fast corners and quick changes of direction, often considered to be representative for handling evaluations. The original, passive vehicle (without torque vectoring) is compared with the application of TV to the various kinematic variants. Fast laps on the driving simulator were also performed by an experienced driver in order to assess the performance potential of each solution, the subjective feeling and also the consistency of consecutive lap times, the latter often being considered as a meaningful indicator of driving intuitiveness and stability, especially in motorsport. The steering wheel angle and steering effort in the space domain along the circuit are shown in Figures 22-26 for all configurations analysed in the previous chapter. The vehicle options are driven on a fixed trajectory by VI-grade's Virtual Driver model, therefore, the subjective driver assessment on the vehicle balance and optimum racing line is removed from the equation.