Design and Kinematic Analysis of an n (2RRU-RRR + 3RPR) Space Capture Mechanism With Collision Buffering

Abstract Space capture technology has become a key element of missions such as space-debris removal and in-orbit servicing. Many existing capture mechanisms struggle to balance structural stiffness and impact resistance. This study proposes a rigid–flexible coupled n(2RRU–RRR+3RPR) space capture mechanism. Each basic unit combines a reconfigurable 2RRU-RRR parallel mechanism as a rigid phalanx cell and a 3RPR parallel mechanism with spring joints as a local buffer joint cell. The buffer joint cells enable switching between high and low stiffness to adapt to different bending angles. The study establishes the kinematic model and develops a fast workspace computation workflow based on coordinate recursion. Under typical parameter settings, the proposed structure extends the contact time by 4.5 times to 0.22 s compared with no damping and reduces the impact force by 81.11% to 2.70 N. It also attains a buffering-to-size ratio of 0.24. The workspace-to-size ratio of 1.64 in the X direction increases by about 20.59%. In the Y direction, it changes from nearly zero to a finite value and extends the workspace from two dimension to three dimension. Overall, the mechanism provides a practical rigid–flexible coupling option of intelligent space capture mechanisms.