Analysis of the Frequency-Dependent Vibration Rectification Error in Area-Variation-Based Capacitive MEMS...

Area of Science:

• MEMS (Micro-Electro-Mechanical Systems) technology
• Inertial sensing and navigation systems

Background:

• Ambient vibrations can degrade accelerometer performance, causing vibration rectification error (VRE).
• VRE is a critical issue for high-precision applications like inertial navigation and tilt measurement.

Purpose of the Study:

• Investigate the origins of VRE in accelerometers.
• Analyze the factors contributing to frequency-dependent nonlinearity in MEMS accelerometers.

Main Methods:

• Utilized a self-developed MEMS accelerometer with an area-variation capacitive displacement transducer.
• Examined the relationship between excitation frequency, displacement amplitude, and nonlinearity coefficients.

Main Results:

• The second-order nonlinearity coefficient showed frequency dependence.
• Vibration rectification error (VRE) remained constant when displacement amplitude was constant.
• Identified key contributing factors: resonance amplification, capacitive nonlinearity (fringing effect), and suspension offset.

Conclusions:

• Optimized the displacement transducer and damping to significantly reduce the second-order nonlinearity coefficient.
• Achieved a substantial reduction in the nonlinearity coefficient from mg/g2 to μg/g2, improving accelerometer performance.