## 3 Statement of Basic Materials
The above results of theoretical studies on reduction and leveling the external loads acting on the UEM actuator when digging the soil were verified and confirmed by experimental studies of the physical model of the actuator (scale 1:5) and its mounting [27; 28] (Figure 2a). The results were obtained with a confidence interval of 0.95, with the experiments being repeated five times. When digging wide trenches (ditches) in the soil, the load of the universal rotor earthmoving machinery is quite complex and is determined by the combined effect of many factors, the value of each of them changes during soil development, is random in nature, and cannot be reliably determined analytically. The experimentally revealed objective pattern of the UEM operating equipment load enables not only to determine the pattern of changes in external loads and the dynamics in this pattern, but also to work out technical proposals to reduce the load. This, eventually, enables to find or confirm the rationality of technical solutions rational technical solutions to ensure and increase the UEM directional stability when developing soils in the mode of the highest efficiency of the machinery. Studies of the physical features of the loads affecting the UEM operating equipment were carried out under the conditions of its operation both in the trench mode and in the mode of translational and rotational supply to the face when constructing wide excavations (ditches) in loamy soils, which are most common in Europe. The profile of the trench developed by UEM is shown in Figure 3a. Ditches in the soil are constructed by the operating equipment of the machinery during one or two passes in the soil (Figure 3b,c). Figure 3: Experimental studies on the physical model of the operating equipment: (**a**) a profile of the developed trench; (**b**) the operating process when constructing a wide excavation; (**c**) a profile of a wide excavation during one or two passes. There is practically no residual spillage in the trench of the minimum width, which is equal to the width of the rotor \(B=0.6\) m. Residual spillage in the ditch (\(B=4.5\) m) reaches 5-7% of its volume (in-kind). The load of the UEM operating equipment depends on a number of factors that determine the machinery operating modes, soil conditions, and face parameters. When conducting the research, the main variables determining the actuator load were established:  
* The actuator supply speed to the face, \(V_{s}\);
* Soil cutting speed, \(V_{c}\);
* The speed of the actuator lateral supply to the face, \(V_{1,m}\);
* The time of the intermediate frame additional rotation when the rotor frame rotation mechanism is stopped at the end of each half cycle, \(t_{\text{ar}}\);
* Soil strength according to Road Scientific and Research Institute _DorNDI_ impactor, \(C\);
* The width of the excavated trench at the level of the daily surface soil, \(b\). The soil strength \(C\) according to the DorNDI impactor is a universal integrated characteristic of soils (both unfrozen and frozen) based on the complexity of their mechanical development. The classification of soils according to the complexity of their development (according to the impactor indicator-DorNDI density meter) was suggested by professor [PERSON] [29]. As a result of experimental research of the operating equipment, it was found that the maximum load of the operating equipment occurs when developing the soil near the lateral walls of the excavation at the end of each half cycle. To evaluate the load peculiarities of the UEM operating in the translational and rotational mode of the actuator supply to the face, the most interesting is the value and points of applying the maximum load on the operating equipment, depending on the value and combinations of factors that determine it.