Automated microassembly by means of a micromanipulator and external sensors

This paper describes an automated microassembly system for the dynamic, flexible handling of 3D microobjects by means of visually guided manipulation unit. We propose a coarse- fine approach to microassembly, where a medium-resolution and a high-resolution monitoring device are used for coarse measurements within a large field of view and for fine sensing at high precision, respectively. A coarse motion device with large working area serves as parts supply and medium-resolution transport unit; the microassembly tasks are executed by a high-resolution fine manipulator. System supervision and control is base don parameter extraction from the visual information acquired by the two monitoring devices. The use of vision systems as external sensors for the control of micromanipulators in assembly tasks allows to directly determine the position of the end-effector and the parts to be manipulated. A relative motion control strategy is proposed for executing the microassembly tasks.