| The development and characteristics of microgripper is discussed. Actuation technologies of micro-mechanical cantilever are summarized, and formula for capacitance and electrostatic force involving edge-effect of comb- drive actuator are derived.A comb-drive electrostatically actuated microgripper and its design process are described in detail. Electro-conductive fingers of gripper are connected to ground, in order to release the electric charges on the surface of fingers and gripping objects. Continuous S-shaped flexures in finger would decrease the stiffness of gripping arm, and slove the contradiction between huge elastic modulus and small surface electrostatic force. Mathematical model of S-shaped finger is setup, and optimum design process is also presented under considering technological conditions and physical dimension of gripper. Finite element method (FEM) is used in structure analysis and simulation of electric field. Fabrication process of the microgripper based on silicon bulk micromachining is designed. Effects of footing and lag in ICP and bonding failure are discussed as emphases. The cantilever type gripping finger that is 6μm wide and 5471μm in equivalent length was released successfully Characteristic of comb-drive electrostatically actuated microgripper is tested. Informations and statuses of microgripper are acquired by test platform of Microscope-CCD-Computer. Voltage-displacement characteristic of microgripper is obtained by image process. Analysis of characteristic equation indicates that theoretical design is consistent with experiment results. Gripper has a gripping range of 12μm to 140μm. Comb-drive actuator could generate more than 12μN gripping force.
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