Tagged: MEMS gyroscope
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March 20, 2024 at 5:16 am #96497Kelly01Participant
MEMS gyroscope is widely used in attitude control platform and inertial navigation as a device to detect the angular rate information of carrier. It has the characteristics of small size, low cost, high reliability and easy integration.
In recent years, the research of MEMS sensor mainly focuses on singleaxis gyro, which can only determine the angular rate of a certain direction. With the progress and maturity of MEMS sensor technology, the accuracy of singleaxis MEMS gyro has gradually improved, and key indicators such as bias stability have been able to meet the application requirements of navigation level (bias stability <10 °/h). However, because singleaxis MEMS gyroscope can only detect the angular velocity from one axis, it has certain limitations, so the research of threeaxis gyroscope has become an important development direction of MEMS sensors.
Because the threeaxis gyroscope can detect angular rates in three different directions, it is more suitable for detecting the position change of objects. By solving the angular rates in three different spatial directions, it can obtain the attitude and inertial motion of the carrier in threedimensional space. However, for a long period of time, three singleaxis gyroscopes need to be orthogonally arranged to realize the angular rate information detection in three axes (X, Y, Z). This paper will introduce three integration methods of threeaxis MEMS gyroscopes.
Orthogonal integration of three single axis MEMS gyroscope
The orthogonal integration of three singleaxis gyros is constructed with three singleaxis gyros. The advantages of the gyros are relatively simple structure (all of them are singleaxis gyros), but the main problems are low integration degree, large assembly error and large system volume. Under normal circumstances, the three singleaxis gyro uses the same structure to save costs and improve the yield (only the same kind of gyro can be processed), at the same time, the control system of the three singleaxis gyro is centralized in a digital chip in the form of a central processing chip, which can also reduce the system volume and reduce the system cost to a certain extent. This method can be used when the singleaxis gyro is mature and the system volume is not high. Figure 1 shows the orthogonal integration form of three singleaxis gyroscopes.
ER3MG01 and ER3MG06 use this orthogonal integration method, respectively, applied to two kinds of bodies, the former can mainly find the north, the latter is mainly a highperformance threeaxis MEMS gyroscope.
Figure 1 Orthogonal integration of 3 axis MEMS gyro
Singlechip singlestructure threeaxis MEMS gyroscope
As shown in Figure 2, the Zaxis detection principle of the structure proposed by Newcastle University is exactly the same as that of the ring gyro. Through the vibration of the driving mode in the plane, the angular rate input of the X and Y axes is detected by the outofplane motion. Although the structure realizes the singlechip threeaxis gyro in principle, the motion amplitude of the X and Y axes is small. The shaft is coupled with each other.
STMicroelectronics proposed a lowpower singlechip threeaxis MEMS gyroscope and equipped it with a threeaxis openloop integrated circuit, the structure of which is shown in Figure 3. The structure adopts the form of mass blockcomb structure, the first mode is the drive mode, the second mode is the inplane detection mode (course angular rate direction), the two outofplane motion modes are the pitch angle rate direction and the roll angle rate detection direction, and the mode resonance frequency is 20 kHz. The structure size is 3.2mm × 3.2mm, the noise level is less than 0.03 °/s/ Hz, and the measuring range is 2000 °/s.
Figure 2 Structure of ring monolithic threeaxis gyroscope proposed by Newcastle University
Figure 3 Structure of monolithic threeaxis gyroscope proposed by STMicroelectronics
Monolithic multistructure MEMS gyroscope array
A single chip multistructure gyro array is composed of multiple single (double) axis gyro structure chips. The HahnSchickardGesellschaft Institute of Microsystems and Information Technology proposed a 7.5 mm×7.5 mm threeaxis gyro array, which relies on two structural forms. The three gyro structures are independent of each other and distributed in a plane, as shown in Figure 4. The bandwidth of Xaxis, Yaxis and Zaxis gyro is 50 Hz, the nonlinearity is ≤0.2%, ≤0.2% and ≤0.1%, and the noise is < 0.45 °/s, < 0.45 °/s and < 0.2 °/s, respectively.
Figure 4 Threeaxis gyro array proposed by HahnSchickardGesellschaft Institute of Microsystems and Information Technology
Agency for Science, Technology and Research, Singapore proposed a combination sensor array of threeaxis gyro and threeaxis accelerometer, in which the Xaxis and Yaxis gyro adopt angular vibration form, and the Zaxis gyro adopts linear vibration form. Its structure is shown in Figure 5. The three axis ranges of the gyroscope are 1000 °/s, and the Xaxis, Yaxis and Zaxis scale factors, nonlinearity, zerobias stability and angular random walk are respectively: LSB / 5.01 ° s, 5.09 LSB / ° LSB / ° / s/s and 12.91, 0.2%, 0.8% and 0.6%, 0.07 ° s, 0.04 ° and 0.03 ° s/s, 0.17 ° s /), 0.14 °/√s and 0.04 °/√s, the structure size is 2.0mm × 2.0mm × 0.5mm.
Figure 5 Threeaxis gyro array proposed by Agency for Science, Technology and Research, Singapore
This article introduces three integration methods for threeaxis MEMS gyroscopes. If you are interested in other knowledge of MEMS gyroscope, please contact us.


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