• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.247-252
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• 2002

A rate gyroscope has been used popularly to measure the angular motion of a given vehicle using a symmetric rotor spinning rapidly about its symmetry axis. Since the rapid rotation is required in this type of gyroscope, the motor has been used to make the rotor spin, so that it results in a heavy configuration. The tuning-fork gyroscope has been developed to avoid this problem, which utilizes a coriolis coupling term and vibration about one axis. Because of the coriolis effect, the vibration of one axis is transferred to other axis when the angular motion along the vibrating axis is given to the system. The concept of a tuning-fork gyroscope was recently realized using MEMS techniques. However, the dynamic characteristics of the tuning-fork gyroscope has not been discussed in detail. In this study, we derived the equations of motion for the tuning-fork type gyroscope using the energy approach and investigated the dynamic characteristics by means of numerical analysis.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1843-1845
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• 1998

Gyroscope is a very important core sensor as a rotation sensor in inertial space, in inertial guidance and navigation system on aeronautics. Plane, vessel and so on for civilian and millitary applications. Research and development of fiber optic gyroscope began in 1976 and focused on improving the gyroscope's sensitivity to rotation. bias performance and reducing noise. We have developed a Interferometric Fiber Optic' Gyroscope using a integrated-optic-circuit (IOC), which is operating with closed-loop electronic circuit. This paper describes the scheme of optical part and electronic part and also test results of this fiber optic gyroscope using a integrated-optic-circuit (IOC). The performance have been achieved as long-term bias drift of $1.73^{\circ}/h$.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.12
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• pp.1001-1009
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• 2002

In this paper, we analyse and present mechanical dynamic characteristics of a micro-machined vibrating silicon ring gyroscope which can measure angular velocities about three orthogonal axes. The ring gyroscope has a ring connected to the gyroscope main body by support-ligaments which are arranged with cyclic symmetry. The natural modes of its vibration can be distinguished into the in-plane motion and the out-of-plane motion which are coupled by the gyro-effect due to the rotation of the gyroscope main body. The equations of motion, the response to angular velocities, and the relationships between the natural modes of vibration are derived and compared with the previous studies for the design of a micro three-axis ring gyroscope.

• The Journal of Korea Robotics Society
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• v.8 no.1
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• pp.29-36
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• 2013

This paper presents a sensitivity optimization of a MEMS (microelectromechanical systems) gyroscope for a magnet-gyro system. The magnet-gyro system, which is a guidance system for a AGV (automatic or automated guided vehicle), uses a magnet positioning system and a yaw gyroscope. The magnet positioning system measures magnetism of a cylindrical magnet embedded on the floor, and AGV is guided by the motion direction angle calculated with the measured magnetism. If the magnet positioning system does not measure the magnetism, the AGV is guided by using angular velocity measured with the gyroscope. The gyroscope used for the magnet-gyro system is usually MEMS type. Because the MEMS gyroscope is made from the process technology in semiconductor device fabrication, it has small size, low-power and low price. However, the MEMS gyroscope has drift phenomenon caused by noise and calculation error. Precision ADC (analog to digital converter) and accurate sensitivity are needed to minimize the drift phenomenon. Therefore, this paper proposes the method of the sensitivity optimization of the MEMS gyroscope using DEAS (dynamic encoding algorithm for searches). For experiment, we used the AGV mounted with a laser navigation system which is able to measure accurate position of the AGV and compared result by the sensitivity value calculated by the proposed method with result by the sensitivity in specification of the MEMS gyroscope. In experimental results, we verified that the sensitivity value through the proposed method can calculate more accurate motion direction angle of the AGV.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.312.1-312
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• 2002

In this paper, we analyse and present mechanical dynamic characteristics of a micro-machined vibrating silicon ring gyroscope which can measure rates of turn about three orthogonal axes. The ring gyroscope has a ring connected to the gyroscope main body by support-ligaments which are arranged with cyclic symmetry. The natural modes of its vibration can be distinguished into the in-plane motion and the out-of-plane motion which are coupled by the gyro-effect due to the rotation of the gyroscope main body. (omitted)

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

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.9
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• pp.1297-1305
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• 2004

Reliability of MEMS devices is receiving more attention as they are heading towards commercial production. In particular are the reliability and long-term stability of wafer level vacuum packaged MEMS gyroscope sensors subjected to cyclic mechanical stresses at high frequencies. In this study, we carried out several reliability tests such as environmental storage, fatigue, shock, and vibration, and we investigated the failure mechanisms of the anodically bonded vacuum gyroscope sensors. It was found that successful vacuum packaging could be achieved through reducing outgassing inside the cavity by deposition of titanium as well as by pre-taking process. The current gyroscope structure is found to be safe from fatigue failure for 1000 hours of operation test. The gyroscope sensor survives the drop and vibration tests without any damage, indicating robustness of the sensor. The reliability test results presented in this study demonstrate that MEMS gyroscope sensor is very close to commercialization.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.519-521
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• 1987

Among the gyroscopes used for SDINS, the dynamically turned gyroscope (DTG) covers a wide dynamic range while it is simple and small. In addition, it is a two-degree-of freedom gyro; it can detect two-axis input simultaneously. DTG, since its development in 1970's, is widely accepted for strapdown inertial systems. In the first year, we have concentrated on developing a two degree-of-freedom DIG. An interdisciplinary research team has been formed to accomplish the first year objective. Five departments in the College of Engineering, Seoul National University are involved. They are; 1) Department of Control and Instrumentation, 2) Department of Mechanical Design and Production, 3) Department of Electrical Engineering, 4) Department of Electronic Engineering, and 5) Department of Metallurgical Engineering. In addition, the Department of Precision Mechanical Engineering of Pusan National University is subcontracted to develop a test procedure for gyroscope and SDINS. Gyroscope is a key sensor for SDINS. Furthermore gyroscope itself is used as a. independent sensor for vehicle guidance and control and fire control system. Gyroscope and SDINS are an important for defense, aeronautical, and space industries that Korea is and will be actively involved. Upon the success of the project, they are expected to be manufactured in Korea under a cooperative effort between university and industry.

• Journal of KSNVE
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• v.11 no.1
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• pp.132-140
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• 2001

The vibratory gyroscope can effectively measure the angular velocity as the oscillating and position-sensing mode are exactly tuned. The veering Phenomenon impedes the exact tuning, which is caused by the mode coupling of two modes. In this paper, the gyroscope's structure with two frames is introduced to minimize the veering phenomenon that destabilizes the tuning process of oscillating and position-sensing mode. Experimental results show that the Proposed structure can achieve the mode intersection without veering phenomenon.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.195-197
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• 1993

In this paper, a planar vibratory gyroscope is designed and fabricated in macro model. Elementary experiment and test are done for micro model. This gyroscope has a double gimbal structure with an active dimension $80{\times}120{\times}1\;mm^3$. Outer gimbal vibration is generated by electromagnetic force using ferrite E-core wounded by coil. Inner gimbal vibration is detected by inductive sensor. It is demonstrated' that mechanical and electrical symmetries are important for improvement of vibratory gyroscope.