## 4 Results and Discussion  
In accordance with the first option for setting the rear attachment device of the MDD power module (Table 1), we consider the dependence of the forces \(N_{a}\) and \(N_{c}\) on the change in angle \(\alpha\) at a zero angle \(\beta\) value (i.e., \(\beta=0^{\circ}\)). An analysis of the calculated data shows the following. At positive values of the parameter \(z\) (Figure 2), an increase in angle \(\alpha\) from 5 to \(35^{\circ}\) leads to an increase in the forces \(N_{a}\) and \(N_{c}\) (Figure 5). However, the regularities of this process for the indicated forces are different. First, at value \(z=0\), the vertical load of the wheels on the front axle of the PM is greater than at \(z=0.30\) m. With the wheels of the MDD technology module, everything is vice versa. Figure 4: Block diagram of the calculation algorithm. Figure 5: Dependence of forces \(N_{a}\) and \(N_{c}\) on the angle of installation of the central link of the rear attached mechanism of the tractor \(\alpha\) with the installed lower \(\beta=0^{\circ}\). Their additional loading is greater, the greater the value of \(z\). Such a result is natural, since, with an increase in this parameter, the leverage of the vertical component \(R_{v}\) of the tractive resistance of the semitrailer increases. This force on the arm tends to rotate the TM clockwise and thus loads its wheels. Second, the smaller the value of angle \(\alpha\), the greater the difference in the values of the force \(N_{a}\) for different (but positive!) values of the parameter \(z\). For force \(N_{c}\), this regularity is valid for greater values of angle \(\alpha\). Besides, when \(z=0.30\) m, and the value \(\alpha\) is more than \(18^{\circ}\), the vertical load on the TM wheels exceeds their maximum load capacity \(N_{cmax}\). As the positive values of the parameter \(z\) decrease, the intensity of the change in the forces \(N_{a}\) and \(N_{c}\) decreases. At \(z=-0.30\) m and \(\beta=0\), the dynamics of the changes in these forces is practically independent of the installation angle of the central link of the rear-attached mechanism of the MDD power module. If, at a positive value of angle \(\alpha\), we set the lower links of the attached mechanism of the PM at a negative angle at the level of \(-10^{\circ}\), then we obtain the following. Only one quantitative change will appear in the dynamics of force \(N_{c}\). Namely, the excess of the maximum load capacity of the TM tires will occur, not at \(\alpha=18^{\circ}\), as in the previous case, but at a value of this angle equal approximately to \(14^{\circ}\) (Figure 6). As for the dynamics of the change of force \(N_{a}\), then, unlike in the previous case (Figure 5), as the value of angle \(\alpha\) increases, the value of the vertical load on the front wheels of the PM, albeit slightly, still decreases. Another thing is that this decrease does not lead to the loss of controllability of the MDD, since the minimum allowed value \(N_{\text{min}}\) of force \(N_{a}\) is at the level of 6 kN, which is about 2.5 times less than its real level. In the second setting variant of the rear attachment of the MDD power module (Table 1), the dynamics of the changes of force \(N_{c}\) (Figure 7) with the increase in angle \(\alpha\) remains similar to that shown in Figure 5.  
Figure 6: Dependence of forces \(N_{a}\) and \(N_{c}\) on the angle \(\alpha\) of installation of the central link of the rear-attachment mechanism of the tractor when installing lower \(\beta=-10^{\circ}\). Besides, there are significant differences in the force \(N_{a}\) changes. With an increase in angle \(\alpha\) from 5 to about \(15^{\circ}\), there is a relatively intense increase in the vertical load on the wheels of the front axle of the MDD power module, as well as for all the values of the parameter \(z\). In addition, at \(\alpha=5^{\circ}\) and \(z=0.3\) m, the value of the force \(N_{a}=4.6\) kN becomes less than the minimum allowed, \(N_{\text{min}}=6.2\) kN.