Micropart feature design for improving visually servoed assemblability

Abstract

Development of hybrid MEMS devices has demonstrated a need for automatic microassembly strategies. Visual servoing techniques have shown great promise as a control strategy capable of submicron precision while compensating many of the problems that exist in the micro domain, including thermal expansion of assembly devices and imprecisely modeled and calibrated sensors and actuators. This project develops rules for micropart design to aid in device assemblability with visual servoing techniques by ensuring that the microparts can be easily tracked and controlled using vision feedback. A criterion is presented that estimates part trackability based on the visual appearance of the part. This criterion is then used to microfabricate features to improve part trackability and hence, the assemblability of the device. The criterion considers the feature appearance when the part lies out of the optical system's depth of the field. A Fourier optics based approach is used to simulate the visual appearance of microparts represented by CAD models using high resolution optical systems. This simulation is used to automatically design microfabricated features on microparts.