Development of a lateral velocity-controlled MEMS vibratory gyroscope and its performance test

The objective of this paper is to present a velocity-controlled vibratory MEMS gyroscope that achieves consistent output characteristics in the lateral driving dynamics of the system. Through a systematic automatic gain control loop design process, the driving mode dynamics of the gyroscope is first transformed to take account of the velocity envelope; a reference tracking integral control is then employed. For stabilized loop construction, a mathematical development and stability analysis of the feedback loop is presented, which is followed by numerical simulation using practical sensor parameters. The mechanical structure was fabricated using the conventional deep reactive ion etching process and the anodic wafer bonding method. Vacuum-packaged devices were used for the resonant gyroscope operation. An essential fabrication process for realizing the electrical connection through a thick glass substrate was possible by applying a sandblasting process and spin coating process of conductive epoxy. Finally, loop simulation and experimental results verified that the amplitude-controlled property in the driving loop is preserved under the system parameter variation which resulted in enhanced gyroscope output performance in comparison with other driving schemes.