## 4 Simulation and Result Analysis
### Fishhook Test  
The basic parameters of the fishhook test simulation analysis are shown in Table 3.  
The results of the fishhook test simulation are shown in Figure 7. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Test Parameters** & **Value** & **Unit** \\ \hline Longitude target speed & 80 & km/h \\ Friction coefficient & 0.85 & - \\ Steer input angle peak value & 294 & deg \\ Simulation time & 20 & second \\ Road condition & straight & - \\ [Threshold of CDC-LTR control] & 0.9 & - \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Main parameters of fishhook test. Figure 7: _Cont._The results of the roll angle, roll velocity, and LTR of these three modes show that both CDC control methods can effectively prevent rollover. The result of the roll angle demonstrates that the roll angle rate of the vehicle with passive suspension reaches \(-6\) rad/s in approximately 3 s, and the roll angle exceeds the limit, thus causing serious rollover. From the result of LTR, the vehicle with passive suspension reaches the rollover threshold at the first turning left in 1 s. Given the influence of some factors, such as sideslip and small inertia, the vehicle is in an unstable state without rollover. However, after the 1.57 th second of continuous right turning, the vehicle can no longer maintain driving. Finally, at approximately the 2.2 th second, LTR jumps directly from \(-1\) to \(+1\), indicating that rollover occurs. At approximately the 3 rd second, the parameter has no significance. However, some LTR values with a discontinuous value of \(+1\) still remain. Comparing the CDC-ODDF control with the CDC-LTR control, the overall parameter performance of the vehicle seems to have little difference. However, it is determined by the rollover critical condition. LTR also reaches \(+1\) from the 2.1 th second to the 2.2 th second under these two control strategies. The rollover cannot happen because the vehicle is in a critical unstable state. This result can be compared through the vertical and damping forces in Figure 8.  
Figure 7: Roll angle, roll angle rate, LTR, and lateral acceleration of fishhook test. The result of passive suspension is expressed by the black dotted line. The result of CDC-LTR is expressed by the blue chained line. The result of CDC- optimal distribution damping force (ODDF) is expressed by the red solid line. (**a**) is the comparison result of the roll angle. (**b**) is the comparison result of the roll angle rate. (**c**) is the comparison result of LTR. (**d**) is the comparison result of lateral acceleration. To observe the comparison of the two CDC control strategies more conveniently, a local view in which passive suspension is removed is added. Figure 8: Vertical and damping forces of each wheel in fishhook test with CDC-LTR and CDC-ODDF. The details can be seen in the legend. (**a**) is the comparison result of the vertical forces of wheels on the left. (**b**) is the comparison result of the vertical forces of wheels on the right. (**c**) is the comparison result of the damping forces of wheels on the left. (**d**) is the comparison result of the damping forces of wheels on the right. L is short for left, and R is short for right. Here, 1 represents the front axle, and 2 denotes the rear axle. The comparison of the vertical forces demonstrates that the time during the wheel load on the same side at the same time is zero if the vehicle with CDC-ODDF is shorter. The vertical force of the right wheel of the rear axle is evidently reduced from the 1.6 th second to the 1.8 th second with CDC-ODDF. The vertical force of the left wheel of the front axle also decreases to a certain extent from the 2.3 th second to the 2.4 th second with CDC-ODDF. It can decrease the load transfer during roll, which is also the reason why the LTR value is less than CDC-LTR control. Moreover, the advantages of CDC-ODDF can be determined by comparing the damping forces, which is the core part of the CDC-ODDF.