Dynamic loading of the hydraulic system elements for the timber transport machine manipulator during alignment of the frame of the pivoting device

Hydraulic manipulators can be used to solve technical tasks on flatlands that have a slope or are arranged on structurally unstable soils. In these conditions, reliable and safe operation of hydraulic manipulators can be ensured by the use of outriggers. The implementation of the alignment process of the pivot platform relative to the horizon can be carried out with different positions of other elements of the manipulator - boom, handle and telescopic extension. At the same time, the loads on the hydraulic cylinders of the mobile system change over time. The intensity of dynamic loading depends on a set of design and operating parameters. A mathematical model is proposed to study the characteristics of dynamic loading of the hydraulic cylinder system of a mobile transport and technological bus. The mathematical model is constructed by a universal method based on Lagrange equations of the 2nd kind for a mechanical system with four degrees of freedom. The model was studied for the case when all the elements of the hydraulic manipulator are loaded, but over time only the angle between the horizontal plane and the plane of the surface of the pivot plate changes. The other elements do not shift relative to the platform. The extension of the outrigger is provided by the operation of a gear pump, therefore, the supply of working fluid is cyclic. The model takes into account pressure pulsations, which cause high-frequency oscillations of the elements of hydraulic units with a significant amplitude. It is shown that an increase in the rotation frequency of the gear pump shaft leads to a decrease in the pressure in the outrigger hydraulic cylinder from the values obtained under equilibrium conditions with the corresponding position of the manipulator elements, as well as to an increase in the amplitude of pressure pulsations as the platform is leveled.