Electrostatic actuated micro gripper using an amplification mechanism

Abstract This paper presents a microgripper using an amplification mechanism coupled to an electrostatic linear motor. The gripper design, particularly the principle of the amplification mechanism based on the combination of ground-links and moving pin-joints, is explained. The linear motor is composed of scratch drive actuator inducing the use of electrostatic forces to obtain quasi-static motion for high accuracy in micropositioning. To corroborate the design, the gripper mechanism has been modeled by finite elements method with different mesh elements via the simulator CASTEM 2000™. Then, the amplification ratio of displacement, the critical buckling load and the force applied to the grasped object are determined. Moreover, the fabrication process requiring four levels of polysilicon are presented and notices based on visual observations of the realized actuator are given. Based on video observations, kinematics characterization of different topologies of the microgripper is performed and a discussion concerning the comparison with the simulation results and the influence of the geometric shapes of jaws/arms on the kinematics parameters is done. Finally, reliability aspects are stated consisting in the determination of the brittleness areas.

[1]  Maria Chiara Carrozza,et al.  The development of a LIGA-microfabricated gripper for micromanipulation tasks , 1998 .

[2]  M. A. Northrup,et al.  Thin Film Shape Memory Alloy Microactuators , 1996, Microelectromechanical Systems (MEMS).

[3]  Stephanus Büttgenbach,et al.  Fabrication and investigation of in-plane compliant SU8 structures for MEMS and their application to micro valves and micro grippers , 2002 .

[4]  P. Bidaud,et al.  Fabrication and characterization of an SU-8 gripper actuated by a shape memory alloy thin film , 2003 .

[5]  Ivo W. Rangelow,et al.  Electrostatically driven microgripper , 2002 .

[6]  李幼升,et al.  Ph , 1989 .

[7]  Stephanus Büttgenbach,et al.  Novel micro-pneumatic actuator for MEMS , 2002 .

[8]  C. Hsu,et al.  Mechanical stability and adhesion of microstructures under capillary forces. II. Experiments , 1993 .

[9]  I. Shimoyama,et al.  A three-dimensional shape memory alloy microelectrode with clipping structure for insect neural recording , 2000, Journal of Microelectromechanical Systems.

[10]  C. Hsu,et al.  Mechanical stability and adhesion of microstructures under capillary forces. I. Basic theory , 1993 .

[11]  I. Shimoyama,et al.  Three dimensional SMA microelectrodes with clipping structure for insect neural recording , 1999, Technical Digest. IEEE International MEMS 99 Conference. Twelfth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.99CH36291).

[12]  R. Muller,et al.  Silicon-processed overhanging microgripper , 1992 .

[13]  K. Pister,et al.  Surface micromachined polysilicon heart cell force transducer , 2000, Journal of Microelectromechanical Systems.

[14]  Hiroyuki Fujita,et al.  Scratch drive actuator with mechanical links for self-assembly of three-dimensional MEMS , 1997 .

[15]  Dominique Collard,et al.  Influence of the Step Covering on Fatigue Phenomenon for Polycrystalline Silicon Micro-Electro-Mechanical-Systems (MEMS) : Instrumentation, Measurement, and Fabrication Technology , 2002 .