• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.946-969
• /
• 2003

Vibration analysis for a coupled MEMS gyroscope design is presented in this paper. MEMS gyroscopes have shown that slight mistuning in fabricated process often leads to significant difference of vibration characteristics between expected and real designs. The difference frequently affects the MEMS gyroscope design in a negative way. As long as the coupling between excited and sensed motions exists, such difference occurs inevitably. In this paper, dimensionless parameters that govern the vibration characteristics of coupled MEMS gyroscope are identified and the effects of the parameters on the vibration characteristics are investigated for the design of the MEMS gyroscope.

• Journal of Sensor Science and Technology
• /
• v.26 no.4
• /
• pp.235-238
• /
• 2017

In this study, the design of a tri-axis micromachined gyroscope is proposed and the vibration characteristic of the structure is analyzed. Tri-axis vibratory gyroscopes that utilize Coriolis effect are the most commonly used micromachined inertial sensors because of their advantages, such as low cost, small packaging size, and low power consumption. The proposed design is a single structure with four proof masses, which are coupled to their adjacent ones. The coupling springs of the proof masses orthogonally transfer the driving vibrational motion. The resonant frequencies of the gyroscope are analyzed by finite element method (FEM) simulation. The suspension beam spring design of proof masses limits the resonance frequencies of four modes, viz., drive mode, pitch, roll and yaw sensing mode in the range of 110 Hz near 21 kHz, 21173 Hz, 21239 Hz, 21244 Hz, and 21280 Hz, respectively. The unwanted modes are separated from the drive and sense modes by more than 700 Hz. Thereafter the drive and the sense mode vibrations are calculated and simulated to confirm the driving feasibility and estimate the sensitivity of the gyroscope. The cross-axis sensitivities caused by driving motion are 1.5 deg/s for both x- and y-axis, and 0.2 deg/s for z-axis.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.48 no.10
• /
• pp.687-692
• /
• 1999

A new technique to measure low level capacitance variations of the gyroscope is proposed and verified by computer simulation. It is based on the new CV(capacitance-voltage) converter circuit biased by dc current source and the peak detector without low pass filter. The CV converter biased by dc current source provides good signal-to-noise ratio and this setup of the detection circuitry without low pass filter makes it possible to provide short settling time, that is, higher speed of measurement and wide operation range if only a few parameters are adjusted. The key parameters that affect the performance of the detection circuitry are illustrated and computer simulation results are presented. The demonstrated detection circuitry shows linear response from 10 fF to 130 fF at 10 kHz and shows good linearity.

• Transactions on Electrical and Electronic Materials
• /
• v.2 no.1
• /
• pp.16-21
• /
• 2001

A new technique to measure low level capacitance variations of a gyroscope is proposed. It is based on the improved CVC(capacitance to voltage converter) biased by a d.c. current source and the peak detector without any low pass filter. This setup of the measurement system makes it possible to provide higher speed of measurement and wide operation range. The d,c, drift of the conventional CVC and stray capacitances are automatically compensated. Key parameters that affect the performance of the measurement system are illustrated and computer simulation results are presented. The demonstrated measurement system for micromachined gyroscope applications shows a linearity of 0.99972 and a resolution of 0.67fF from 10 fF to 120 fF at 10 kHz.

• Proceedings of the KIEE Conference
• /
• 2000.07c
• /
• pp.2230-2232
• /
• 2000

This paper reports an electrostatically driven and electromagnetically sensed planar vibratory gyroscope based on a surface-bulk combined micromachining. The fabricated structure has comb electrodes which are 400${\mu}m$ thick, 18${\mu}m$ wide, 600${\mu}m$ long and separated by 7${\mu}m$ so that the height-gap ratio is about 57. It also has electroplated gold springs which are 15${\mu}m$ wide, 14${\mu}m$ thick and 500${\mu}m$ long on both sides of the seismic mass. The open-loop characteristics of fabricated gyroscope at atmospheric pressure are measured on a rate table. The fabricated gyroscope has a sensitivity of 30mV/deg/sec, and a resolution of 0.1deg/sec at atmospheric pressure. It is expected that non linearity of full scale output is less than 0.8% with. the dynamic range of $\pm$500deg/sec.

• Proceedings of the KIEE Conference
• /
• 2004.11a
• /
• pp.275-277
• /
• 2004

This paper presents design and fabrication of micromachined accelerometer using $100{\mu}m$ thick SiOG substrate. The proposed accelerometer has a resonant frequency, 6kHz. To reduce the off-axis sensitivity of the accelerometer, the mode characteristic of the accelerometer is investigated using ANSYs modal analysis. Because the accelerometer is fabricated using an SiOG substrate, it is expected to be integrated as one-chip IMU sensor with a gyroscope using an SiOG substrate.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.11a
• /
• pp.88-91
• /
• 2005

Although the MEMS element is made through a very precise manufacturing process, usually there is the difference between the modeling design and the actual product. So tuning is required. Through the frequency tuning(changing the characteristics of device), we can calibrate the fabrication error and uncertainty. I'll propose the method of changing the natural frequency through the imposing the axial force on the anchor part to separate the sensing part and the tuning part. When the shape of section is the form of rectangular, the degree of the natural frequencies' change under axial force appears D be different. Applying a tuning force of 30 $\mu$N, the natural frequencies' difference can be reduced by 5 percent.