Research of the Manipulator Vibration Mode Under Variable Joint Impedance

Manipulators are providing increasing convenience to human society due to their advantages in loading and endurance. However, vibration restricts their further application in human lives. Vibrations arise from the infinite degrees of freedom of the flexible joints and links and the finite dimensions of controllers, which can be essentially studied in the mode space by dimensional reduction. This paper investigates the relationship between modes and joint impedance of a manipulator through finite element simulation. The results demonstrate that stiffness can increase mode frequencies and enhance vibration amplitudes. Damping weakens the influence of stiffness on modes and alters modal shapes. The research confirms that modes of manipulators are able to be controlled through joint impedance, laying the groundwork for further research on vibration suppression through mode control.