Dynamic coupling of space robots with flexible appendages

For a space robot with flexible appendages, the structure flexibilities will easily cause vibration during orbit and/or attitude maneuver of the base, and the operation of the manipulators. Hence, the pose (position and attitude) of the end-effector will deviate from the desired values largely. In this paper, we derive the rigid-flexible coupling dynamics of a space robot system with flexible appendages and establish the coupling model between the flexible structure and the space manipulator. Then, some coupling factors are defined to measure the coupling degree between the flexible motion of the appendages and the rigid motion of the end-effector. Moreover, a new type of coupling map is proposed and drawn in joint space to represent the coupling motion between the joint and the appendages. The coupling map is very important for trajectory planning to reduce appendage vibration. The above work supplies a theoretic basis to guide the system design, performance evaluation, trajectory planning and motion control of such space robots.