Optical Manipulation of Multiple Groups of Microobjects Using Robotic Tweezers

Micromanipulation has received increasing attention from robotics researchers due to its wide applications in the manipulation of microobjects like biological cells and Bio-MEMS components. The demand for accurate and precise manipulation of microobjects opens up new challenges in automation of micromanipulation tasks. In this paper, we present a concurrent framework for optical manipulation of multiple groups of microobjects using robotic tweezers. The proposed framework is based on laser-stage coordination control and consists of two concurrent subschemes: 1) local coordination achieved by asynchronous manipulation of multiple groups of microobjects using laser beams and 2) global coordination achieved by manipulation of whole groups using a motorized stage. Unlike existing methods that are limited to the manipulation of a single microobject or a single group of microobjects, the proposed method considers concurrent laser-stage coordination of multiple groups of microobjects, which enhances the capability and flexibility in micromanipulation tasks. In addition, we introduce a unified social interaction function to achieve various cellular behaviors. A mathematical formulation is provided and stability analysis is presented. Using the proposed method, we are able to manipulate multiple groups of microobjects to construct time-varying microformations. Experimental results are presented to illustrate the performance of the proposed method.