A Real-Time Circuit Phase Delay Correction System for MEMS Vibratory Gyroscopes.

Area of Science:

• Micro-electromechanical Systems (MEMS)
• Control Systems Engineering
• Sensor Technology

Background:

• Advancements in MEMS gyroscope design highlight the critical role of control circuit systems.
• Phase delay in electronic components poses significant performance limitations and hazards for MEMS gyroscopes.

Purpose of the Study:

• To develop and validate a real-time circuit phase delay correction system for MEMS vibratory gyroscopes.
• To analyze the impact of circuit phase delay on in-phase and quadrature (IQ) coupling and zero-rate output (ZRO).

Main Methods:

• Theoretical analysis of circuit phase delay effects on gyroscope characteristics.
• Implementation of a force-to-rebalance (FTR) closed-loop detection and quadrature correction system.
• Real-time adjustment of the phase-locked loop (PLL) phase reference value to compensate for circuit phase delay.

Main Results:

• The developed system accurately measures and compensates for circuit phase delay in real time.
• Elimination of unwanted IQ coupling and a 755% reduction in ZRO to 0.095°/s.
• Achieved small angle random walk of 0.978°/√h, bias instability of 9.458°/h, and scale factor nonlinearity of 255 ppm.
• Reduced ZRO thermal drift to 0.0034°/s/°C across a -20 to 70 °C temperature range.

Conclusions:

• The real-time correction system effectively mitigates the adverse effects of circuit phase delay in MEMS gyroscopes.
• Significant improvements in gyroscope performance, including ZRO, random walk, bias instability, and thermal drift, were demonstrated.
• This system offers a viable solution for enhancing the precision and reliability of MEMS vibratory gyroscopes.