The Characteristics and Locking Process of Nonlinear MEMS Gyroscopes

Area of Science:

• Nonlinear dynamics
• Micro-electro-mechanical systems (MEMS)

Background:

• Miniaturization of MEMS gyroscopes necessitates understanding their nonlinearity.
• Phase-frequency characteristics are critical for gyroscope applicability, impacting start-up time.
• While amplitude-frequency effects are studied, phase response in nonlinear gyroscopes remains underexplored.

Purpose of the Study:

• To investigate the characteristics and locking process of nonlinear MEMS gyroscopes.
• To analyze the impact of nonlinearity on phase-frequency response and phase-locked loop (PLL) actuation.
• To develop a method to accelerate the PLL locking process in nonlinear gyroscopes.

Main Methods:

• Solving the dynamic equation using the harmonic balance method.
• Simulating the PLL actuation process with an iterative calculation method.
• Designing and implementing a nonlinear PLL (NPLL) with an integrator.

Main Results:

• Identified overhanging and multi-valued phenomena in amplitude-frequency and phase-frequency curves.
• Demonstrated that nonlinearity can retard PLL locking time under specific conditions.
• Showcased experimental evidence of aggravated nonlinearity effects due to high quality factors.

Conclusions:

• Nonlinearity in MEMS gyroscopes significantly influences phase-frequency characteristics and PLL locking dynamics.
• A designed NPLL effectively accelerates the gyroscope start-up process.
• The study provides insights into managing nonlinearity for improved MEMS gyroscope performance.