## 5 Discussion  
To verify the effectiveness of the control strategy, the vehicle steering performance was simulated and the road parameters were selected as shown in Table 2.  
The simulation and verification of the control strategy was performed under four typical steering conditions with different slope angles on the ground, as follows:  
1. The simulation conditions are: the initial vehicle speed is 3 m/s, when t = 10 s, the steering angle speed input by the driver is 2.5 rad/s. If the angle sensor detects \(\alpha=0^{\circ}\), According to Formula (19), the maximum steering angular speed corresponding to the vehicle speed of 3 m/s is 1.96 rad/s, which does not achieve the target steering angular speed of 2.5 rad/s. Therefore, to achieve the desired steering command, the vehicle speed needs to be adjusted automatically. Figure 9a shows the curve of the steering control signal, the inside and outside speed of the track, and the central vehicle speed under this condition. Figure 9b shows the pressure change curve of the hydraulic motors on both sides during steering. The simulation results in Figure 9a show that the steering angular speed input by the driver increases from 0 to 2.5 rad/s in the interval 10-10.5 s, and because the control signal had not reached 1.96 rad/s, the control strategy does not work in the interval between 10 and 10.5 s; the inner speed is decreased and the outer speed is increased, while the vehicle speed remains unchanged during steering, which fits the characteristics of differential steering. When the angular velocity exceeds 1.96 rad/s, the control rules automatically adjust the driving speed so that the speeds of the inner and outer tracks change simultaneously, while the vehicle speed is automatically adjusted to 2.35 m/s in 1.3 s, completing the desired steering requirement of 2.5 rad/s. At the same time. Figure 9b shows that the pressures of the hydraulic motors on both sides do not exceed the pressure limit of 31.5 Mpa. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Value** \\ \hline Rolling resistance coefficient \(f\) & 0.1 \\ Steering resistance coefficient \(\mu_{\text{max}}\) & 0.8 \\ Lateral adhesion coefficient \(\psi\) & 0.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Road parameters in simulation. Figure 9: Simulation curves of operation under Condition 1: (**a**) simulation curve of vehicle speed and steering angular velocity; (**b**) simulation curve of pressure on both sides. 2. The simulation conditions are: Initial speed is 2.8 m/s, when t = 10 s, the steering angle speed input by the driver is 2.2 rad/s. If the angle sensor detects \(\alpha=30^{\circ}\) for uphill driving steering, according to Formula (19), the maximum steering angular speed corresponding to the vehicle speed of 2.8 m/s is 1.82 rad/s, which does not achieve the target steering angular speed of 2.2 rad/s. Therefore, to perform the desired steering command, the vehicle speed needs to be adjusted automatically. Figure 10a is the curve of the steering control signal, the inside and outside speeds of the track, and the central vehicle speed in this condition. Figure 10b shows the pressure change curve of the hydraulic motors on both sides during steering. On the basis of the simulation results presented in Figure 10a, the steering angular speed inputs by the driver increase from 0 to 2.2 rad/s in the interval 10-10.5 s. Because the steering control signal input has not yet reached 1.82 rad/s, the control strategy does not work in the interval between 10 and 10.5 s; the inside speed is decreased and the outside speed is increased, while the vehicle speed remains unchanged during steering, which fits the characteristics of differential steering.