Design and fabrication of a novel tri-axis gyroscope with sensing diagonal-pendulums

In this paper, we present a novel design of tri-axis gyroscope which consists of two diagonal-pendulum masses for lateral sensing, coupled with and enclosed in a traditional tuning fork driving frame. The diagonal-pendulums are driven to swing via tilted transforming beams as the driving frame oscillated in plane, and rotate around their torsional beam out-of-plane as orthogonal lateral angular rate applied. The symmetric arrangement of whole structure lowers mechanical complexity and the sensing way of "one diagonal-pendulum for one lateral axis" eliminates sensing proof mass sharing which can effectively suppress the cross-talk effect. The prototype device has been successfully fabricated by using SOI-based bulk micromachining processes and vacuum packaged by Al---Ge eutectic bonding. The sensitivities for three axes are 4.83, 1.47 and 1.38 mV/(°/s), respectively, with nonlinearity of less 1 % and bandwidth of above 600 Hz.