Path planning for micro-part assembly by using active stereo vision with a rotational mirror

Our proposed active vision system for micro assembly is equipped with a top view camera and a side view camera with a rotational mirror system, such that the viewing direction can be changed freely. The rotational side view helps minimize an occlusion by changing the view direction and measuring three-dimensional (3-D) information using stereo reconstruction. We investigate the global path planning problem, which considers obstacles and occlusions on the image space of each camera simultaneously. General 3-D space-based path planning algorithms may fail in terms of successful safe path generation due to camera or system calibration uncertainty. The proposed approach generates a safe path on two image spaces using a fast marching method, and follows this path based on a visual tracking method in the image space. In order to avoid a visual occlusion and obstacle, the travel cost is built by using a potential field method. For efficient path generation in image spaces, epipolar boundary constraints are considered in the potential field generation. Simulation and experimental results show the feasibility of the proposed algorithm for the assembly of microelectromechanical system parts.