A Tuning Fork Gyroscope with a Polygon-Shaped Vibration Beam.

Area of Science:

• Micro Electro Mechanical Systems (MEMS)
• Inertial Sensors
• Vibratory Gyroscopes

Background:

• Tuning fork gyroscopes are crucial for motion sensing.
• Optimizing vibration structures is key to improving gyroscope performance and signal-to-noise ratio (SNR).

Purpose of the Study:

• To propose and analyze a novel tuning fork gyroscope utilizing a polygon-shaped vibration beam.
• To investigate the impact of spindle azimuth on gyroscope performance, including driving amplitude and capacitance gap.

Main Methods:

• Design and simulation of a polygon-shaped vibration beam structure.
• Optimization of spindle azimuth considering driving amplitude and voltage.
• Fabrication using wet and dry etching processes.
• Packaging in a vacuum ceramic tube.
• Implementation of a closed-loop control circuit with automatic gain control and weak capacitance detection.

Main Results:

• The optimized spindle azimuth improves driving amplitude and reduces capacitance gap, enhancing SNR.
• The fabricated Micro Electro Mechanical Systems (MEMS) gyroscope achieved a bias instability of 0.589°/h.
• Angular random walk (ARW) was measured at 0.038°/√h with a bandwidth exceeding 100 Hz.
• The system operated effectively within a full-scale range of ± 200°/s at room temperature.

Conclusions:

• The proposed polygon-shaped vibration beam design offers significant performance improvements for tuning fork gyroscopes.
• The optimized design and advanced control circuitry result in a high-precision Micro Electro Mechanical Systems (MEMS) gyroscope suitable for demanding applications.