Design and performance test of a MEMS vibratory gyroscope with a novel AGC force rebalance control

• Published in: Journal of micromechanics and microengineering Vol. 17; no. 10; pp. 1939 - 1948
• Main Authors: Sung, Woon-Tahk, Sung, Sangkyung, Lee, Jang Gyu, Kang, Taesam
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.10.2007; Institute of Physics
• Subjects: Applied sciences; Electronics; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Measurements common to several branches of physics and astronomy; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Metrology, measurements and laboratory procedures; Microelectronic fabrication (materials and surfaces technology); Micromechanical devices and systems; Physics; Precision engineering, watch making; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Velocity, acceleration and rotation; Vacuum soldering; Great depth; Anodic bonding; Measurement sensor; Control synthesis; Experimental study; Wafer bonding; Reactive ion etching; Quality factor; Bandwidth; Automatic control; Ion beam etching; Gyroscopes; Force control; Microelectromechanical device; Biased estimation
• ISSN: 0960-1317; 1361-6439
• DOI: 10.1088/0960-1317/17/10/003

In this paper, the development and performance test results of a laterally oscillating MEMS gyroscope using a novel force rebalance control strategy are presented. The micromachined structure and electrodes are fabricated using the deep reactive ion etching (DRIE) and anodic wafer bonding process. The high quality factor required for the resonance-based sensor is achieved using a vacuum-sealed device package. A systematic design approach of the force rebalance control is applied via a modified automatic gain control (AGC) method. The rebalance control design takes advantages of a novel AGC loop modification, which allows the approximation of the system's dynamics into a simple linear form. Using the proposed modification of AGC and the rebalance strategy that maintains a biased oscillation, a number of performance improvements including bandwidth extension and widened operating range were observed to be achieved. Finally, the experimental results of the gyroscope's practical application verify the feasibility and performance of the developed sensor.