• KEPCO Journal on Electric Power and Energy
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• v.6 no.4
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• pp.405-411
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• 2020

In this paper, we designed the COS MEMS system for sensing the falling detection and explosive noise of fuse link in COS (Cut Out Switch) installing on the power distribution. This system analyzed the failure characteristics and an instantaneous breakdown of power distribution. Therefore, our system strengths the industrial competence and guaranties the stable power supply. In this paper, we applied BLE (Bluetooth Low Energy) technology which is suitable protocol for low data rate, low power consumption and low-cost sensor applications. We experimented with LSM6DSOX which is system-in-module featuring 3 axis digital accelerometer and gyroscope boosting in high-performance mode and enabling always-on low-power features for an optimal motion for the COS fuse holder. Also, we used the MP34DT05-A for gathering an ultra-compact, low power, omnidirectional, digital MEMS microphone built with a capacitive sensing element and an IC interface. The proposed COS MEMS system is developed based on nRF52 SoC (System on Chip), and contained a 3-axis digital accelerometer, a digital microphone, and a SD card. In this paper of experiment steps, we analyzed the performance of COS MEMS system with gathering the accelerometer raw data and the PDM (Pulse Data Modulation) data of MEMS microphone for broadcasting the failure of COS status.

• Journal of Korea Society of Digital Industry and Information Management
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• v.18 no.4
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• pp.47-54
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• 2022

In this paper, MEMS embedded system design implemented the sensor events via analyzing the characteristics that dynamically happened to an abnormal status in power IoT environments in order to guarantee a maintainable operation. We used three kinds of tools in this paper, at first Bluetooth Low Energy (BLE) technology which is a suitable protocol that provides a low data rate, low power consumption, and low-cost sensor applications. Secondly LSM6DSOX, a system-in-module containing a 3-axis digital accelerometer and gyroscope with low-power features for optimal motion. Thirdly BM1422AGMV Digital Magnetometer IC, a 3-axis magnetic sensor with an I2C interface and a magnetic measurable range of ±120 uT, which incorporates magneto-impedance elements to detect the magnetic field when the current flowed in the power devices. The proposed MEMS system was developed based on an nRF5340 System on Chip (SoC), previously compared to the standalone embedded system without bluetooth technology via mobile App. And also, MEMS embedded system with BLE 5.0 technology broadcasted the MEMS system status to Android mobile server. The experiment results enhanced the performance of MEMS system design by combination of sensors, BLE technology and mobile application.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.3
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• pp.258-264
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• 2009

This paper presents two control algorithms for the frequency and amplitude of the resonator of a micro sensor. One algorithm excites the resonator at its a priori unknown resonant frequency, and the other algorithm alters the resonator dynamics to place the resonant frequency at a fixed frequency, chosen by the designer. Both algorithms maintain a specified amplitude of oscillations. The control system behavior is analyzed using an averaging method, and a quantitative criterion is provided for the selecting the control gain to achieve stability. Tracking and estimation accuracy of the natural frequency under the presence of measurement noise is also analyzed. The proposed control algorithms are applied to the MEMS dual-mass gyroscope without mechanical connecting beam between two proof-masses. Simulation results show the effectiveness of the proposed control algorithms which guarantee the proof-masses of the gyroscope to move in opposite directions with the same resonant frequency and oscillation amplitude.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.8 s.227
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• pp.1065-1074
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• 2004

A robust optimal design considering fabrication influence has been performed for the decoupled vibratory microgyroscope fabricated by the bulk micromachining. For the analysis of the gyroscope, a design tool has been developed, by which user can perform the system level design considering electric signal process and the fabrication influence as well as mechanical characteristics. An initial design of the gyroscope is performed satisfying the performances of scale factor (or sensitivity) and phase delay, which depend on the frequency difference between driving and sensing resonant frequencies. The objective functions are formulated in order to reduce the variances of the frequency difference and the frequency in itself by fabrication error. To certify the results, the standard deviations are calculated through the Monte Caries Simulation (MCS) and compared initial deviation that is measured fabricated gyroscope chip.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1466-1470
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• 2007

MEMS design flow based on DFM concept is presented and applied to gyroscope design as a test case. It is purposed to contribute to the yield improvement by considering the process-related parameters from the design phase. After defining the performance requirements, the sensitivity analysis should be done on the draft design(s) to find out the key parameters related with the device performance. By doing so, TEG can be designed for the selected process and/or material parameters. Through a set of test runs, the process capability is characterized and the material properties are extracted using the TEG. Then we can estimate the virtual yield of the current process for the designed device by running Monte Carlo analysis where the process and/or material property variations are considered. The estimated yield will make us redesign the device to be more robust or improve the current process to have the smaller variations.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.195-198
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• 2002

현재의 광통신, 이동통신 및 디지털 시대에서는 보다 소형화되고, 대용량의 데이터 저장 및 다기능 소자에 대한 요구가 많아지고 있다. 이러한 전자 산업 환경에서 MEMS 소자는 여러 요구조건을 만족시킬 수 있는 특징을 갖추고 있으며 실제 소자의 제작에 있어서 MEMS 소자를 이용하여 여러 물리 및 화학 센서 및 Actuator 제작에 응용이 되어지고 있고 Optical switch, Gyroscope, 적외선 어레이 센서, 가속도 센서, 위치 센서 등 여러 분야에서 실용화가 진행되어지고 있다. MEMS 구조물의 packaging 방법에 있어서는 내부 MEMS 소자의 동작을 위한 외부 환경으로부터의 보호를 위하여 Hermetic sealing에 대한 요구를 만족시켜야 한다. 본 발표에서는 이와 같은 MEMS device의 진공 패키지를 구현함에 있어서 기판 내부에 수동소자를 실장할 수 있는 LTCC 기술을 이용하여 진공 패키징하는 방법에 대하여 소개한다. 본 기술을 이용하는 경우 기존의 Hermetic sealing 이외에 향후 적층 기판 내부에 수동소자를 내장시켜 배선 길이 및 노이즈 성분을 감소시켜 더욱 전기적 성능을 향상시킬 수 있는 장점이 있게된다. 본 논문에서는 LTCC 기판을 이용하여 패키징 시킨 후, 내부 진공도에 영향을 줄 수 있는 계면들에서의 시간에 따른 진공도 변화의 특성치를 측정하여 LTCC 기판의 Hermetic sealing 특성에 관하여 조사하였다.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.6
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• pp.546-554
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• 2012

This paper suggests a design method of an improved phase control loop for tracking resonant frequency of solid type precision resonant gyroscope. In general, a low cost MEMS gyroscope adapts the automatic gain control loops by taking a velocity feedback configuration. This control technique for controlling the resonance amplitude shows a stable performance. But in terms of resonant frequency tracking, this technique shows an unreliable performance due to phase errors because the AGC method cannot provide an active phase control capability. For the resonance control loop design of a solid type precision resonant gyroscope, this paper presents a phase domain control loop based on linear PLL (Phase Locked Loop). In particular, phase control loop is exploited using a higher order PLL loop filter by extending the first order active PI (Proportion-Integral) filter. For the verification of the proposed loop design, a hemispherical resonant gyroscope is considered. Numerical simulation result demonstrates that the control loop shows a robust performance against initial resonant frequency gap between resonator and voltage control oscillator. Also it is verified that the designed loop achieves a stable oscillation even under the initial frequency gap condition of about 25 Hz, which amounts to about 1% of the natural frequency of a conventional resonant gyroscope.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.7
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• pp.632-637
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• 2012

This paper introduces a simple and efficient calibration method for three-axis accelerometers and three-axis gyroscopes using three-axis motion rate table. Usually, the performance of low cost MEMS-based inertial sensors is affected by scale and bias errors significantly. The calibration of these errors is a bothersome problem, but the previous calibration methods cannot propose simple and efficient method to calibrate the errors of three-axis inertial sensors. This paper introduces a new simple and efficient method for the calibration of accelerometer and gyroscope. By using a three-axis motion rate table, this method can calibrate the accelerometer and gyroscope simultaneously and simply. Experimental results confirm the performance of the proposed method.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.33-35
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• 2005

In this paper, a two-mass system for SiOG (Silicon on Glass) vibratory gyroscope with the need of frequency tuning was proposed to increase the stability of the device with wide bandwidth. Air damping and bandwidth were analyzed using MATLAB. The measured resonance frequency is 5.2 kHz, which is 7 kHz in the design. But the measured bandwidth is 450 Hz, similar to the designed bandwidth with 500 Hz. Also the frequency difference (210 Hz) between the driving and sensing part is smaller than the wide bandwidth of two mass system.

• Journal of the Semiconductor & Display Technology
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• v.9 no.2
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• pp.41-47
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• 2010

In this paper we suggest an improvement upon the previous method of estimating a body's attitude. This paper presents a method that overcomes the shortcomings of previous studies. Applying the method of separating the acceleration of gravity component from the accelerometer's output improves the performance of the attitude estimation and extends the scope. In order to apply the method of the attitude estimation in an actively moving body, a new acceleration value containing the acceleration of gravity is calculated. This paper also proposes the method which minimizes the estimation error in estimating the moving body's attitude which is changing rapidly. Finally, this paper suggests a method that detects the gyroscope's drift and compensates for this drift using accelerometer. Applying the method improves the performance of the attitude estimation.