Microassembly of Complex and Solid 3D MEMS by 3D Vision-based Control

This paper describes the vision-based methods developed for assembly of complex and solid 3D MEMS (micro electromechanical systems) structures. The microassembly process is based on sequential robotic operations such as planar positioning, gripping, orientation in space and insertion tasks. Each of these microassembly tasks is performed using a pose-based visual control. To be able to control the microassembly process, a 3D model-based tracker is used. This tracker is able to directly provide the 3D micro-object pose at real-time and from only a single view of the scene. The methods proposed in this paper are validated on an automatic assembly of fives silicon microparts of 400 mu m x 400 mu m x 100 mu m on 3-levels. The insertion tolerance (mechanical play) is estimated to 3 mu m. The precision of this insertion tolerance allows us to obtain solid and complex micro electromechanical structures without any external joining (glue, wending. Promising positioning and orientation accuracies are obtained who can reach 0.3 mu m in position and 0.2 degrees in orientation.