Design of Electromagnetic Drive Module for Micro-gyroscope

For micro-gyroscopes, the angular rate detection components have to oscillate forwards and backwards alternatively. An innovative design of micro-electromagnetic drive module is proposed to make a Π-type disc reciprocally and efficiently rotate within a certain of angular interval. Twelve Electromagnetic poles enclosing the thin disc are designed to provide the magnetic drive power. Isotropic etching technique is employed to fabricate the high-aspect-ratio trench, so that the contact angle of wire against trench can be increased and the potential defect of cavities and pores within the wire can be prevented. On the other hand, a Π-type thin disc is designed to conduct the pitch motion as an angular excitation, in addition to spinning, is exerted on the gyroscope. The efficacy of the micro-magnetic drive module is verified by the commercial software, Ansoft Maxewll. In comparison with the conventional planar windings in micro-scale systems, the magnetic drive force is increased by 150%.

• Nan-Chyuan Tsai
• Jiun-Sheng Liou
• Chih-Che Lin
• Tuan Li

• Micro-gyroscope
• micro-electromagnetic
• micro actuator.

[1] C. W. Lai, S. K. Hsiung, C. L. Yeh, A. Chiou, G. B. Lee, "A cell delivery
and pre-positioning system utilizing microfluidic devices for dual-beam
optical trap-and-stretch," Sensors and Actuators B: Chemical, vol. 135,
pp. 388-397, 2008.
[2] J. Cho, T. Wiser, C. Richards, D. Bahr, R. Richards, "Fabrication and
characterization of a thermal switch," Sensors and Actuators A: Physical,
vol. 133, pp. 55-63, 2007.
[3] C. Acar, "Robust Micromachined Vibratory Gyroscope," Ph.D. Thesis,
Universuty of California at Berkeley, 2004.
[4] N.-C. Tsai, C.-Y. Sue, "Fabrication and Analysis of a Micro-machined
Tri-axis Gyroscope," Journal of Micromechanics and Microengineering,
vol. 18, p. 115014, 2008.
[5] R. linnemann, P. Woias, C. D. Senfft, J. A. Ditterich, "A Self-Priming and
Bubble-Tolerant Piezoelectric Silicon Micropump for Liquids and Gases",
Proceedings IEEE Micro Electro Mechanical Systems, 1998, pp. 532-537.
[6] L. S. Fan, Y. C. Tai, R. S. Muller, "IC-Processed Electrostatic
Micro-motors," Tech Dig Int Electron Devices Meeting, 1988. IEDM '88.
Technical Digest., 1988, pp. 666-669.
[7] A. Beyzavi, N. T. Nguyen, "Modeling and optimization of planar
microcoils", Journal of Micromechanics and Microengineering, vol. 18,
p. 095018, 2008.
[8] C. H. Ahn, M. G. Allen, "A Comparison of Two Micromachined
Inductors (Bar- and Meander- Type) for Fully Integrated Boost DC-DC
Power Converters", IEEE Transactions on Power Electronics, vol. 11, pp.
239-245, 1996.