Dependence of error sensitivity of frequency on bias voltage in force-balanced micro accelerometer

Abstract

To predict more precisely the frequency of force-balanced micro accelerometer with different bias voltages, the effects of bias voltages on error sensitivity of frequency is studied. The resonance frequency of accelerometer under closed loop control is derived according to its operation principle, and its error sensitivity is derived and analyzed under over etching structure according to the characteristics of Deep Reaction Ion Etching (DRIE). Based on the theoretical results, micro accelerometer is fabricated and tested to study the influences of AC bias voltage and DC bias voltage on sensitivity, respectively. Experimental results indicate that the relative errors between test data and theory data are less than 7%, and the fluctuating value of error sensitivity under the range of voltage adjustment is less than 0.01 μm^-1. It is concluded that the error sensitivity with designed parameters of structure, circuit and process error can be used to predict the frequency of accelerometer with no need to consider the influence of bias voltage.

Key words： Micro-Electro-Mechanical Systems (MEMS); micro accelerometer; force-balanced micro accelerometer; frequency; error sensitivity

Acknowledgements

This research was partially supported by the National Natural Science Foundation of China (Grant No. 51175437), the Fundamental Research Funds for the Central Universities (No. ZYGX2011J085). The authors would like to acknowledge Dr. Zhang Fengtian, Mr. Shi Zhigui and Mr. Du Lianming for their assistance in fabrication and experiments.

References

1 Shao P G, Wang L D, Ren Y T. New progress of MEMS component and instrument. Optics and Precision Engineering, 1999, 7: 10-15

2 Liu S F, Ma T H, Hou W. Design and fabrication of a new miniaturized capacitive accelerometer. Sensors and Actuators A, Physical, 2008, 147(1): 70-74

3 Aaltonen L, Halonen K. Continuous-time interface for a micromachined capacitive accelerometer with NEA of 4 μg and bandwidth of 300 Hz. Sensors and Actuators A, Physical, 2009, 154(1): 46-56

4 Che L F, Xu Z N, Xiong B. Response model of capacitive accelerometer with voltage feedback for quasi-static signal and step signal. Chinese Journal of Mechanical Engineering, 2004, 40(10): 102-108

5 Li J, Gao Z Y, Dong J X. Study on estimation of the proof mass of a MEMS accelerometer. Chinese Journal of Mechanical Engineering, 2004, 40(3): 115-118

6 Rudolf F, Jornod A, Bergqvist J, Leuthold H. Precision accelerometer with μg resolution. Sensors and Actuators A, Physical, 1990, 21(1-3): 297-302

7 Yin L, Chen W P, Liu X W. CMOS interface circuit for closed-loop accelerometer. Optics and Precision Engineering, 2009, 17: 1311-1315

8 Soen J, Voda A, Condemine C. Controller design for a closed-loop micromachined accelerometer. Control Engineering Practice, 2007, 15(1): 57-68

9 Tan X Y, Zhou X Z, Jiang Y M. Comparative analysis of Sigma Delta modulation and pulse code modulation in micro-accelerometer. Optics and Precision Engineering, 2009, 17: 1228-1232

10 Zhou W, He X P, Su W. Nonlinear errors of force-balanced micro accelerometer. China Mechanical Engineering, 2009, 20: 1791-1793

11 Zhang Y F, Liu X W, Chen W P. System-level modeling and simulation of force-balance MEMS accelerometers. Journal of Semiconductors, 2000, 29: 917-922

12 Zhou W, Li B L, He X P. Calibration study of force-balanced micro accelerometer based on least squared method and genetic algorithm. In: Proceedings of the IEEE International Conference on Mechatronics and Automation, 2009: 1357-1361

13 Bao M H, Huang Y P, Yang H. Reliable operation conditions of capacitive inertial sensor for step and shock signals. Sensors and Actuators, 2004, A114: 41-48

14 Chau K, Lewis S, Zhao Y. An integrated force-balanced capacitive accelerometer for low-G applications. In: Proceedings of the IEEE International Conference on Solid-State Sensors and Actuators, <month>June</month><day>25-29</day>, 1995: 593-596