Overcoming adhesion forces: Active release of micro objects in micromanipulation

Due to force scaling laws, rapid, accurate release of micro objects has been a long-standing challenge for microrobotic manipulation. This paper presents an active release technique that for the first time, achieves 100% repeatability and a release accuracy of 0.70plusmn0.46mum, experimentally quantified through the manipulation of 10mum glass spheres under an optical microscope. Using a new MEMS (microelectromechanical systems) microgripper, this technique employs a controllable plunging mechanism for the micro object to gain sufficient momentum to overcome adhesion forces. Experimental results also confirmed that this technique is not substrate dependent. Theoretical analyses were conducted to understand the release principle. Based on this preliminary study, the technique may also prove to be an effective solution to active release of sub-micron objects in robotic pick-place.