Nonlinear dynamics of space manipulator system considering planetary gear joints

This paper investigates the nonlinear dynamics of a 7-degree-of-freedom (7-DOF) space manipulator considering the effects of planetary gear joints. This work firstly proposes a dynamic model for planetary gear joints using lumped parameter analysis. The dynamic model takes into account non-linear factors such as meshing stiffness of the external and internal gears, backlash and meshing displacement that affect the performance of the manipulator. The model is then applied to a 7-DOF manipulator system. The dynamic responses of the manipulator under constant and smooth velocity operation conditions are analyzed, showing that smooth velocity strategy effectively reduces shock and improves motion stability of the manipulator. The results indicate that the manipulator with gear joints exhibits strong non-linear characteristics. This study provides valuable insights for improving the accuracy and stability of space manipulators in practical applications.