Mathematical model of dynamic modes of hydraulic manipulators on timber carriers with slewing bearings levelers

The article discusses the possibility of using automatic pitch and roll levelers in the slewing bearings of hydraulic manipulators of timber carriers in order to increase their productivity and safety of loading and unloading operations in the forestry complex. The analysis of the existing and prospective designs of the slewing bearings levelers of the hydraulic manipulators of forestry machines is given. The study of the hydraulic drive operating modes of the slewing bearings levelers of the fellerbuncher LP-19 B revealed that in the starting and braking modes the frequencies of the pressure oscillations of the working fluid in the hydraulic cylinders of the equalizer were in the range 69.9-994.0 / s for high frequencies and in the range 2.5-2.8 1 / s for low frequencies, while the dynamic coefficient was in the range of 1.00-4.53. The obtained results cannot be fully applied to the aligners of the slewing bearings of truck hydraulic manipulators, because the leveling systems of fellerbunchers are in contact with the machine body, and the truck outriggers rest on the ground. Mathematical models of the operating modes of the hydraulic drive for lifting the boom and outriggers of a hydraulic manipulator of the LV-190 type of a timber carrier that are integrated with an automatic roll-pitch equalizer have been developed. The models allowed the authors to obtain time dependences of the pressure in the working cavities of the hydraulic cylinders of the boom and outriggers when they are separately and jointly connected; as well as the current angular displacement of the rotary support and the manipulator boom. A preliminary analysis of mathematical models carried out using a computer program and experimental studies of a hydraulic drive dynamics on a bench hydraulic manipulator LV-210 showed that the time dependences of the pressure in the cavities of the hydraulic cylinders of the boom and outrigger, as well as the angles of inclination of the supporting-slewing device and the lifting of the manipulator boom, can be used to assess the influence of the hydraulic drive of the automatic leveler on the dynamic modes and stability of the truck hydraulic manipulator under various operating conditions.The abovementioned mathematical model is necessary for carrying out the computer experiments witch finally allow to receive the dependence between the pressure in the piston cavity and the inclination angle of supporting and turning device.