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Design and Analysis of a Novel Fully Decoupled Tri-axis Linear Vibratory Gyroscope with Matched Modes.

Xia D, Kong L, Gao H - Sensors (Basel) (2015)

Bottom Line: With the help of the finite element method (FEM) software ANSYS, the natural frequencies of drive, yaw, and pitch/roll modes are found to be 14,017 Hz, 14,018 Hz and 14,020 Hz, respectively.The cross-axis effect and scale factor of each mode are also simulated.All the simulation results are in good accordance with the theoretical analysis, which means the design is effective and worthy of further investigation on the integration of tri-axis accelerometers on the same single chip to form an inertial measurement unit.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Micro Inertial Instruments and Advanced Navigation Technology of the Ministry of Education, School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China. xiadz_1999@163.com.

ABSTRACT
We present in this paper a novel fully decoupled silicon micromachined tri-axis linear vibratory gyroscope. The proposed gyroscope structure is highly symmetrical and can be limited to an area of about 8.5 mm × 8.5 mm. It can differentially detect three axes' angular velocities at the same time. By elaborately arranging different beams, anchors and sensing frames, the drive and sense modes are fully decoupled from each other. Moreover, the quadrature error correction and frequency tuning functions are taken into consideration in the structure design for all the sense modes. Since there exists an unwanted in-plane rotational mode, theoretical analysis is implemented to eliminate it. To accelerate the mode matching process, the particle swam optimization (PSO) algorithm is adopted and a frequency split of 149 Hz is first achieved by this method. Then, after two steps of manual adjustment of the springs' dimensions, the frequency gap is further decreased to 3 Hz. With the help of the finite element method (FEM) software ANSYS, the natural frequencies of drive, yaw, and pitch/roll modes are found to be 14,017 Hz, 14,018 Hz and 14,020 Hz, respectively. The cross-axis effect and scale factor of each mode are also simulated. All the simulation results are in good accordance with the theoretical analysis, which means the design is effective and worthy of further investigation on the integration of tri-axis accelerometers on the same single chip to form an inertial measurement unit.

No MeSH data available.


Equivalent bias drift versus sense mode frequencies before and after quadrature error correction.
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sensors-15-16929-f013: Equivalent bias drift versus sense mode frequencies before and after quadrature error correction.

Mentions: Assuming that the coupling stiffnesses kyx = kpx = 1 N/m, the bias drift can be calculated by the multiplication demodulation method according to the displacement expressions in Equations (55)~(58). The bias drift can be described as equivalent input angular rates around the sense directions. The relationship of bias drift and the frequency split in the drive and sense modes are depicted in Figure 13. It is assumed that the quadrature errors are reduced to 5% of the original values after correction. Thus the equivalent bias drifts are 7.6 °/s and 3.9 °/s before quadrature error correction, 0.4 °/s and 0.2 °/s after quadrature error correction in the yaw and pitch/roll modes, respectively.


Design and Analysis of a Novel Fully Decoupled Tri-axis Linear Vibratory Gyroscope with Matched Modes.

Xia D, Kong L, Gao H - Sensors (Basel) (2015)

Equivalent bias drift versus sense mode frequencies before and after quadrature error correction.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541915&req=5

sensors-15-16929-f013: Equivalent bias drift versus sense mode frequencies before and after quadrature error correction.
Mentions: Assuming that the coupling stiffnesses kyx = kpx = 1 N/m, the bias drift can be calculated by the multiplication demodulation method according to the displacement expressions in Equations (55)~(58). The bias drift can be described as equivalent input angular rates around the sense directions. The relationship of bias drift and the frequency split in the drive and sense modes are depicted in Figure 13. It is assumed that the quadrature errors are reduced to 5% of the original values after correction. Thus the equivalent bias drifts are 7.6 °/s and 3.9 °/s before quadrature error correction, 0.4 °/s and 0.2 °/s after quadrature error correction in the yaw and pitch/roll modes, respectively.

Bottom Line: With the help of the finite element method (FEM) software ANSYS, the natural frequencies of drive, yaw, and pitch/roll modes are found to be 14,017 Hz, 14,018 Hz and 14,020 Hz, respectively.The cross-axis effect and scale factor of each mode are also simulated.All the simulation results are in good accordance with the theoretical analysis, which means the design is effective and worthy of further investigation on the integration of tri-axis accelerometers on the same single chip to form an inertial measurement unit.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Micro Inertial Instruments and Advanced Navigation Technology of the Ministry of Education, School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China. xiadz_1999@163.com.

ABSTRACT
We present in this paper a novel fully decoupled silicon micromachined tri-axis linear vibratory gyroscope. The proposed gyroscope structure is highly symmetrical and can be limited to an area of about 8.5 mm × 8.5 mm. It can differentially detect three axes' angular velocities at the same time. By elaborately arranging different beams, anchors and sensing frames, the drive and sense modes are fully decoupled from each other. Moreover, the quadrature error correction and frequency tuning functions are taken into consideration in the structure design for all the sense modes. Since there exists an unwanted in-plane rotational mode, theoretical analysis is implemented to eliminate it. To accelerate the mode matching process, the particle swam optimization (PSO) algorithm is adopted and a frequency split of 149 Hz is first achieved by this method. Then, after two steps of manual adjustment of the springs' dimensions, the frequency gap is further decreased to 3 Hz. With the help of the finite element method (FEM) software ANSYS, the natural frequencies of drive, yaw, and pitch/roll modes are found to be 14,017 Hz, 14,018 Hz and 14,020 Hz, respectively. The cross-axis effect and scale factor of each mode are also simulated. All the simulation results are in good accordance with the theoretical analysis, which means the design is effective and worthy of further investigation on the integration of tri-axis accelerometers on the same single chip to form an inertial measurement unit.

No MeSH data available.