An Assembly Process Modeling and Analysis for Robotic Multiple Peg-in-hole

In this paper, the geometric analyses and force/moment analyses of three-dimensional multiple-peg insertions are presented. First, the geometric features of three-dimensional assembly objects are represented by two elements. The geometric conditions for each contact state are derived with the transformation matrix. Second, the contact forces are described by the screw theory in three dimensions. The small motions of the peg around the contact points (the small motion rules) are improved, so the redundant problem can be overcome and the magnitude of the contact force can be obtained. Third, the maximum angle's steepest descent algorithm is proposed to infer the motion direction. Based on the analyses, a simulation program and an experiment of a triple peg-in-hole insertion are presented. The results show that the methods above are effective in finishing the triple peg-in-hole assembly task.