Visual Servo Feedback Control of a Novel Large Working Range Micro Manipulation System for Microassembly

This paper presents a novel micro manipulation system based on visual servo feedback control, which is composed of a micro/nano positioning stage with large workspace, a micro gripper, and a microscope-based visual servo system. The positioning stage is featured with compliant flexure-based totally decoupled characteristics, which is driven by electromagnetic actuators. The gripper is designed with its arms moving completely parallel, which has a large displacement of gripping range. In this research, the gripper is mounted onto the micro positioning stage to form a micro-hand dedicated to micro assembly application. A microscope is adopted to observe this tiny view field and capture the information about the position of the gripping fingers and the objects. Meanwhile, a small piece of silver wire with a diameter of about 30 microns is used as the micro part. The positioning information about tips of the gripping fingers and the object can be captured via the digital microscope and processed by a novel rapid identification method. A kind of visual servo feedback tracking and gripping control algorithm is developed. The algorithm is validated through experiments by realizing the task of picking up a small piece of silver wire then placing it to a new place precisely.