Modeling of cables with additional relocatable mass for fully and under-constrained cable-driven parallel robot

The article examined cable-driven robots and methods of dealing with vibration. The configurations of cable robots, their advantages, and disadvantages, the problems and methods of reconfiguration of cable robots were considered. The identity of the models of under-constrained and constrained cable robots is shown under certain conditions. A mathematical model of cable vibrations was created, and numerical modeling of axial and transverse vibrations of cables with additional mass was done for constrained and under-constrained cable robots on the equilibrium position in the MSC Adams program. A decrease in the main frequency of longitudinal vibrations is shown, consequently, the cutoff frequency when moving the load away from the pulley and an increase in its mass. The appearance of high-frequency oscillations was also recorded, which were not observed in systems without additional weights. An increase in the frequency of transverse oscillations with a decrease of the distance to the load and a decrease in its mass is demonstrated. A deterioration of the properties of a system with additional weights on cables relative to a system without them is demonstrated for different configurations of a cable robot. Transverse and axial vibrations appeared with frequencies that differed from the main ones at times with different configurations. In some configurations, there are even two such frequencies.