• 한국통신학회논문지
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• 제40권2호
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• pp.397-407
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• 2015

본 논문에서는 최근 스마트폰이나 웨어러블 디바이스처럼 IoT/M2M 을 위한 여러 종류의 모바일 기기에 사용되는 센서 중에서 각속도를 검출하는데 사용되는 3축 자이로스코프 센서 IC와 가속도를 검출하는데 사용되는 3축 가속도 센서IC를 1 chip으로 하는 6축 관성센서 IC를 설계하였다. 특히 본 논문에는 자이로스코프 센서의 잡음을 분석하고 이를 효과적으로 제거하기 위한 구조를 제안하였다. 자이로스코프 센서는 가속도 센서, 지자기 센서와 더불어 사용자의 동작을 인식하고, 상대적 위치를 추정하기 위한 용도로 사용되는 센서이다. 위치를 추정할 때 사용되는 센서는 아주 작은 잡음이라도 오차로 누적되기 때문에, 정확도를 높이기 위해서 저잡음 IC 설계가 아주 중요한 요소이다. 본 논문에서는 자이로스코프 센서를 모델링하고 MEMS(micro-electro-mechanical system)와 회로에서 발생하는 잡음의 주파수 특성을 분석하여 이를 효과적으로 제거하기 위한 회로 구조를 제안하였으며, 초소형, 저전력 환경에서 사용 가능하면서 잡음 수준이 아주 낮은 3축 자이로스코프 센서와 3축 가속도 센서를 포함하는 6축 1 chip IC를 제작하였다. 제작된 IC는 자이로스코프 센서 잡음의 주요 원인이 되는 quadrature error를 효과적으로 제거하기 위한 회로 구조를 사용하였고, 0.18um CMOS공정을 이용하여 0.01dps/${\sqrt{Hz}}$의 자이로스코프 센서 잡음밀도를 가지는 IC를 제작하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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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.

• 한국운동역학회지
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• 제21권4호
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• pp.495-501
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• 2011

The purpose of this study was to develop the inertial sensor module system to detect gait event using single angular rate sensor(gyroscope), and evaluate the accuracy of this system. This sensor module is attached at the heel and gait events such as heel strike, foot flat, heel off, toe off are detected by using proposed automatic event detection algorithm. The developed algorithm detect characteristics of pitch data of the gyroscope to find gait event. To evaluate the accuracy of system, 3D motion capture system was used and synchronized with sensor module system for comparison of gait event timings. In experiment, 6 subjects performed 5 trials level walking with 3 different conditions such as slow, preferred and fast. Results showed that gait event timings by sensor module system are similar to that by kinematic data, because maximum absolute errors were under 37.4msec regardless of gait velocity. Therefore, this system can be used to detect gait events. Although this system has advantages of small, light weight, long-term monitoring and high accuracy, it is necessary to improve the system to get other gait information such as gait velocity, stride length, step width and joint angles.

• 한국통신학회논문지
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• 제39C권1호
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• pp.82-89
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• 2014

최근 M2M/IoT에 대한 관심이 높아지면서 디바이스의 위치와 자세 등을 인식할 수 있는 동작 인식 센서의 필요성이 대두되고 있다. 본 논문에서는 소형의 디바이스에 적합하도록 저잡음, 저전력, 초소형 6축 관성센서 IC를 구현하였다. 본 논문에서 구현된 IC는 3축의 압전형 자이로 센서와 3축의 압저항형 가속도 센서를 사용하며, 3축의 자이로스코프 감지 회로, 자이로스코프 센서 구동 회로, 3축의 가속도 감지 회로, 16bit sigma-delta ADC, 디지털 필터와 제어 회로로 구성되어 있다. 본 IC은 TSMC $0.18{\mu}m$ mixed signal CMOS공정으로 개발되었으며, STM사의 6축 관성 센서인 LSM330의 소비전류 6.1mA보다는 약 27% 낮은 4.5mA의 소비 전류로 동작한다.

• Smart Structures and Systems
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• 제31권3호
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• pp.301-309
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• 2023

Tilt is a key indicator of structural safety. Real-time monitoring of tilt responses helps to evaluate structural condition, enable cost-effective maintenance, and enhance lifetime resilience. This paper presents a prototype wireless sensing system for structural tilt measurement. Long range (LoRa) technology is adopted by the sensing system to offer long-range wireless communication with low power consumption. The sensor integrates a gyroscope and an accelerometer as the sensing module. Although tilt can be estimated from the gyroscope or the accelerometer measurements, these estimates suffer from either drift issue or high noise. To address this challenging issue and obtain more reliable tilt results, two sensor fusion algorithms, the complementary filter and the Kalman filter, are investigated to fully exploit the advantages of both gyroscope and accelerometer measurements. Numerical simulation is carried out to validate and compare the sensor fusion algorithms. Laboratory experiment is conducted on a simply supported beam under moving vehicle load to further investigate the performance of the proposed wireless tilt sensing system.

• 한국멀티미디어학회논문지
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• 제20권8호
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• pp.1421-1429
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• 2017

Human activity recognition has been studied using various sensors and algorithms. Human activity recognition can be divided into sensor based and vision based on the method. In this paper, we proposed an activity recognition system using acceleration sensor and gyroscope sensor in smartphone among sensor based methods. We used Deep Belief Network (DBN), which is one of the most popular deep learning methods, to improve an accuracy of human activity recognition. DBN uses the entire input set as a common input. However, because of the characteristics of different time window depending on the type of human activity, the RBMs, which is a component of DBN, are configured hierarchically by combining them from different time windows. As a result of applying to real data, The proposed human activity recognition system showed stable precision.

• 센서학회지
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• 제24권4호
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• pp.274-279
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• 2015

This paper describes optimizing fabrication methods for 2-axis electrically levitated MEMS gyroscope. Electrostatically levitated gyroscope has very high potential of performance due to the fact that its proof mass is not mechanically bound to any other structures, but its complex structure and difficulty of fabrication holds back the research that only a few researches have been reported. In this work, fabrication method for glass-silicon-glass 3-floor structure for 2-axis electrically levitated MEMS gyroscope is presented, including simplified multi-level glass etch method utilizing photoresist attack, preventing metal diffusion by adding middle layer of metal electrode, overcoming Deep RIE limitation by separate fabrication of silicon structures and keeping the electrode safe from dicing debris.

• 제어로봇시스템학회논문지
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• 제15권3호
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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.

• 센서학회지
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• 제5권4호
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• pp.47-56
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• 1996

속도제어루프내에서 외란의 각속도를 감지하여 짐발을 안정화시키기 위해 사용하는 동조자이로스코프에 대한 기본원리 및 특성을 분석하였다. 또한 비례모드 자이로스코프의 모델을 정확하게 제시하였으며, 제시된 모델은 공진 특성을 가지고 있기 때문에 기존에 사용하고 있는 2차 시스템 모델보다 실제 시스템의 특성과 유사하므로 일반적인 비례모드 자이로스코프에서도 적용 가능하다. 실제 시스템인 전자광학추적기에 사용할 경우 발생되는 문제점을 알아보고 그 해결 방안을 제시하였다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제3권2호
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• pp.103-116
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• 2003

We carry out reliability tests and investigate the failure mechanisms. of the wafer level vacuum packaged MEMS gyroscope sensor using an accelerated degradation test. The accelerated degradation test (ADT) is used to evaluate reliability (and/or life) of the MEMS vacuum package and to select the accelerated test conditions, which reduce the reliability testing time. Using the failure distribution model and stress-life model, we are able to estimate the average life time of the vacuum package, which is well agreed with the measured data. After improving several package reliability issues such as prevention of gas diffusion through package, we carry out another set of accelerated tests at the chosen acceleration level. The results show that reliability of the vacuum packaged gyroscope has been greatly improved and can survive without degradation of performance, which is the Q-factor in gyroscope sensor, during environmental stress reliability tests.