VIBRATION SUPPRESSION EXPERIMENTS OF FLEXIBLE PAYLOAD TRANSPORTATION BY SPACE ROBOTIC ARM WITH REDUNDANT DOF

Abstract

In this paper, we consider a practical operational method of a space robotic manipulator with redundant degrees of freedom (DOF), which handles a flexible and massive payload on a flexible structure. First, we study dynamics of transporting massive flexible payload on the flexible structure by the space robotic arm in numerical analyses and preliminary experiments using a 2-dimensional microgravity experimental system. Next, we apply Input Shaping method to suppress the residual vibration due to flexibilities, and examine appropriate command profiles to operate the arm. Input Shaping is adopted to velocity commands of the arm end-effector (E.E.) for suppressing the flexible base induced vibration with the help of the arm DOF redundancy. Then we conduct several payload transportation experiments in 2-dimensional microgravity with simultaneous consideration of suppressing residual vibrations of both the flexible base and the flexible payload. The experimental results show that the proposed vibration suppression method is much efficient, and that the residual vibration can be suppressed less than 20%. We will report the results of numerical analyses and 2-dimensional microgravity experiments in detail in the paper.