| The performance of vibratory micromachined gyroscopes has been continuously improving for the past two decades. However, to further improve performance of the MEMS gyroscope in harsh environment, it is necessary for gyros to reduce the sensitivity to environmental parameters, including vibration and temperature change. In addition, conventional rate-mode MEMS gyroscopes have limitation in performance due to tradeoff between resolution, bandwidth, and full-scale range.;In this research, we aim to reduce vibration sensitivity by developing gyros that operate in the balanced mode. The balanced mode creates zero net momentum and reduces energy loss through an anchor. The gyro can differentially cancel measurement errors from external vibration along both sensor axes. The vibration sensitivity of the balanced-mode gyroscope including structural imbalance from microfabrication reduces as the absolute difference between in-phase parasitic mode and operating mode frequencies increases. The parasitic sensing mode frequency is designed larger than the operating mode frequency to achieve both improved vibration insensitivity and shock resistivity. A single anchor is used in order to minimize thermoresidual stress change.;We developed two gyroscope based on these design principles. The Balanced Oscillating Gyro (BOG) is a quad-mass tuning-fork rate gyroscope. The relationship between gyro design and modal characteristics is studied extensively using finite element method (FEM). The gyro is fabricated using the planar Si-on-glass (SOG) process with a device thickness of 100microm. The BOG is evaluated using the first-generation analog interface circuitry. Under a frequency mismatch of 5Hz between driving and sense modes, the angle random walk (ARW) is measured to be 0.44°/sec/✓Hz. The performance is limited by quadrature error and low-frequency noise in the circuit.;The Cylindrical Rate-Integrating Gyroscope (CING) operates in whole-angle mode. The gyro is completely axisymmetric and self-aligned to maximize mechanical isotropy. The gyro offers a large frequency ratio of ∼1.7 between parasitic and the wineglass modes. The CING is fabricated using the 3D Si-on-glass (SOG) process with a device thickness of 300microm. The 1st and 2nd generation CINGs operate at 18kHz and 3kHz, respectively and demonstrate a frequency mismatch of < 1% and a large Q (∼20,000 at 18kHz and ∼100,000 at 3kHz under exact mode matching). In the rate-sensing mode, the first-generation CING (18kHz) demonstrates an Ag of 0.05, an angle random walk (ARW) of 7°/✓hr, and a bias stability of 72°/hr without temperature compensation. The performance is limited by the Ag, white noise in the phase-lock loop (PLL) in the interface circuitry, and temperature control. In the rate-sensing mode, the second-generation CING measures an Ag of 0.0065, an ARW of 0.09°/✓hr, and a bias stability of 129°/hr without temperature compensation. The performance is limited by A g and XXVI temperature compensation. In the rate-integration mode, the gyro demonstrates precession with an Ag of 0.011+/-0.001 under a frequency mismatch of 20∼80mHz during several hours of operation. |
