Active control of adhesion force for pick-and-place of micro objects with compound vibration in micromanipulation

Due to scale effects, the reliable pick-and-place manipulation of micro objects has been still a long-standing challenge in scientific and technological field. This paper presents an active method to manipulate microobjects, which employs inertia force and compound vibration to overcome adhesion forces. The compound vibration comes from electrostatic actuator and piezoelectrically driven microactuator. A micromanipulation system is set up to test and verify the proposed method. The system consists of a microgripper and a piezoelectric ceramics module. Surface and bulk micromachining technology is employed to fabricate the microgripper used in the system from a single crystal silicon wafer. Theoretical analyses were conducted to understand the release principle. Experiments were carried out through the manipulation of 30–80µm polystyrene spheres under an optical microscope. Experimental results show that this method can achieve a repeatability of 100% with releasing accuracy of 4µm, and is substrate independent. Based on this preliminary study, the system prove to be an effective solution for the active pick-and-place manipulation of microobjects.