Theoretical and experimental analysis of an off-chip microgripper

This paper describes the design of a single-crystal-silicon off-chip electrothermal microgripper for use in micro-assembly and biological applications. Initially, a mechanical and thermal analysis is conducted with simulations of the gripper’s operation using finite element software. The gripper is fabricated using silicon-on-insulator (SOI) technology and is then post-processed, assembled, and tested. The experimental and simulation results are compared, and, on average, the experimental gripper is found to require slightly less than half the power anticipated from the simulation results. The power needed to close the jaws the required 20 μm is determined experimentally to be approximately 33 mW, and the theoretical estimate of average chevron temperature change required to achieve this action is 165 K. The gripper is able to pick up and hold micro-sized objects that simulate biological cells.

[1]  T. Hubbard,et al.  Force, deflection and power measurements of toggled microthermal actuators , 2004 .

[2]  R. Buser,et al.  Tactile microgripper for automated handling of microparts , 1996 .

[3]  Robert Hull,et al.  Properties of Crystalline Silicon , 1999 .

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

[5]  Chieh Kung,et al.  Analysis of the optimal dimension on the electrothermal microactuator , 2002 .

[6]  Nikolai Dechev,et al.  Microassembly of 3D MEMS structures utilizing a MEMS microgripper with a robotic manipulator , 2003, 2003 IEEE International Conference on Robotics and Automation (Cat. No.03CH37422).

[7]  Y. Gianchandani,et al.  Bent-beam electro-thermal actuators for high force applications , 1999, Technical Digest. IEEE International MEMS 99 Conference. Twelfth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.99CH36291).

[8]  Bradley J. Nelson,et al.  A flexible experimental workcell for efficient and reliable wafer-level 3D micro-assembly , 2001, Proceedings 2001 ICRA. IEEE International Conference on Robotics and Automation (Cat. No.01CH37164).

[9]  Paolo Dario,et al.  Manipulating biological and mechanical micro-objects using LIGA-microfabricated end-effectors , 1998, Proceedings. 1998 IEEE International Conference on Robotics and Automation (Cat. No.98CH36146).

[10]  Manfred H. Jericho,et al.  Micro-electro-mechanical systems microtweezers for the manipulation of bacteria and small particles , 2004 .

[11]  T. Hubbard,et al.  Time and frequency response of two-arm micromachined thermal actuators , 2003 .

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

[13]  W. Cleghorn,et al.  Microassembly of 3-D microstructures using a compliant, passive microgripper , 2004, Journal of Microelectromechanical Systems.

[14]  G. K. Ananthasuresh,et al.  Comprehensive thermal modelling and characterization of an electro-thermal-compliant microactuator , 2001 .

[15]  Ole Hansen,et al.  Electro-thermally actuated microgrippers with integrated force-feedback , 2005 .

[16]  M. Sinclair,et al.  A high force low area MEMS thermal actuator , 2000, ITHERM 2000. The Seventh Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.00CH37069).