• 한국군사과학기술학회지
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• 제9권4호
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• pp.71-80
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• 2006

Strapdown Inertial navigation systems consist of an inertial sensor assembly(ISA), electronic modules to process sensor data, and a navigation computer to calculate attitude, velocity and position. In the ISA, most gryoscopes such as RLGs and FOGs, have digital output, but typical accelerometers use current as an analog output. For a high precision inertial navigation system, sufficient stability and resolution of the accelerometer board converting the analog accelerometer output into digital data needs to be guaranteed. To achieve this precision, the asymmetric error and A/D reset scale error of the accelerometer board must be properly compensated. If the relation between the acceleration error and the errors of boards are exactly known, the compensation and estimation techniques for the errors may be well developed. However, the A/D Reset scale error consists of a pulse-train type term with a period inversely proportional to an input acceleration additional to a proportional term, which makes it difficult to estimate. In this paper, the effects on the acceleration output for auto-pilot situations and the effects of A/D reset scale errors during horizontal alignment are qualitatively analyzed. The result can be applied to the development of the real-time compensation technique for A/D reset scale error and the derivation of the design parameters for accelerometer board.

• 한국지반공학회논문집
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• 제36권10호
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• pp.41-56
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• 2020

지진 경보 시스템이 빠르고 정확하게 가동하기 위해서는 충분한 수량의 계측 시스템 확보와 더불어서 적절한 계측 데이터 해석기술 개발이 요구된다. 신규 지진계를 설치시 많은 비용이 소모되기 때문에, 열차 내 가속도계 등을 대체재로 지진 경보 시스템에 활용하는 것이 효율적이다. 그러나 열차에 설치된 가속도계의 경우, 지진계와는 달리 열차 주행시 진동 데이터가 포함되어 있다. 또한, 지진 발생시 성토구간에 의해서 변화된 지진응답을 계측하게 된다. 본 연구에서는 위의 특성들이 포함된 열차 가속도계 데이터에 기반한 지진감지 기술을 제안하고자 한다. 우선, 성토구간의 지진응답 해석기법을 활용하여 열차가 성토구간을 지날 때 지진이 발생하는 것을 구현한 가상의 열차 가속도 데이터를 구축하였다. 구축한 가속도 데이터를 Short time Fourier Transform(STFT)와 Wavelet Transform(WT)을 활용하여 시간-주파수 분석을 수행하였다. 분석 결과, STFT가 장주기 지진 감지에 적합한 반면, WT의 경우 단주기 지진 감지에 유용함을 확인하였다.

• 한국항해학회지
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• 제24권3호
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• pp.103-111
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• 2000

From a ship's safe operation point of view, it is very important to estimate the navigational safety in a seaway. The seakeeping performance can be defined as the ability of a ship to go to sea, and to accomplish its missions successfully and safely even in adverse environmental conditions. There are several factors presently adopted for evaluating seakeeping performance. But a hardware of the system considering all these factors has not been developed since some of them can not be measured by sensors. In this paper, a synthetic method of evaluating navigational safety is developed by measuring the vertical and lateral acceleration. An experiment by using real measuring carried out on board the T/S 'HANNARA' The equipment was measured every 4 hours for more than 30 minutes the acceleration by accelerometer, analyzed its acceleration values and calculated navigational dangerousness. As the results of this on board experiment, the system is carried conviction to be useful as evaluating seakeeping performance.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권6호
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• pp.342-350
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• 2003

In this paper, a levitation controller for a magnetic levitation(MagLev) system is designed and implemented. The target to be controlled is PEM(permanent and electromagnet) type with 4-corners levitation which is open-loop unstable, highly non-linear and time-varying system. The digital control system consists of a VME-based CPU board, AD board, PU board, 4-Quadrant chopper, and gap sensor, accelerometer as feedback sensors. In order to estimate the velocity of the magnet, we used 2nd-order state observer with acceleration and gap signal as input and output, respectively. Using the estimated states, a state feedback control law for the plant is designed and the feedback gains are selected by using the pole-placement method. The designed controller is experimentally validated by step-type gap reference change and force disturbance test.

• 제어로봇시스템학회논문지
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• 제17권12호
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• pp.1194-1202
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• 2011

A touch panel system has been one of the most widely used input devices. In this study, a touch panel embedded system using accelerometers is considered in order to make commercial white-boards or plates into touch panels. Three accelerometers are located at different positions on such a white board, so that touch points on the board can be identified using the sensors. For the identification of touch points, a TDOA (Time Difference of Arrivals) technique is applied in the algorithm which was implemented in a DSP board (TI 6713 DSK), which can provide a precise touch location by using the cross-correlation function of measured signals from the three accelerometers. Experiment results show that the touch panel system with accelerometers could provide the exact touch location. Thus a novel approach using such accelerometers could be applied to a new touch panel system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.883-886
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• 2005

This paper proposed a wireless measurement system (WMS) for an effective condition monitoring using wireless communication. WMS consists of two parts: transmitter(TM) acquired a dynamic signal from physical system using ICP type accelerometer sensor. An acquired signal modulated through the low/high pass filter and amplifier in DAQ board, which converted to digital signal. Embedded board(E-board) transferred digital signals to base station(BS) through the socket IEEE.802.11.b. BS is adopted IOCP server structure. Because it can acquired signal well during transferred digital signal. Signal processing used LabVIEW Library, BS(server) designed to realize multi-thread using visual C++.NET for 1 many meaning data processing

• 전기학회논문지
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• 제56권5호
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• pp.990-992
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• 2007

The purpose of this study is to develop a practical gait-event detection system which is necessary for the FES (functional electrical stimulation) control of locomotion in paralyzed patients. The system is comprised of a sensor board and an event recognition algorithm. We focused on the practicality improvement of the system through 1) using accelerometer to get the angle of shank and dispensing with the foot-switches having limitation in indoor or barefoot usage and 2) using a rule-base instead of threshold to determine the heel-off/heel-strike events corresponding the stimulation on/off timing. The sensor signals are transmitted through RF communication and gait-events was detected using the peaks in shank angle. The system could detect two critical gait-events in all five paralyzed patients. The standard deviation of the gait events time from the peaks were smaller when 1.5Hz cutoff frequency was used in the derivation of the shank angle from the acceleration signals.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.173-178
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• 1998

An automatic Q. C. tester for a production line of electric grinder is developed using vibration signals. The methods of measuring and analyzing the vibration signals are found through several experiments at laboratory and production line. The experiments show that checking a vibration signal at running condition only, without any sound signal, is enough to judge whether the product is good or not. The Q. C. tester is made of accelerometer and PC. Measured vibration signal using accelerometer is transmitted to PC through A/D board. Vibration level are calculated using FFT algorithm in PC for already selected five frequency bands, which can specify the cause of fault. The Judging criteria of vibration levels of each bands are decided through a lot of experiment with the comparison of manual judgement.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.439-439
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• 2000

In this paper, the relationship among the vertical acceleration, measuring points and walking patterns is analyzed. To measure acceleration, the acceleration measurement unit and communication board is constructed. It uses MEMS accelerometer ADXL-202 that detects 2-axis acceleration simultaneously. It is shown by the experiment test that the walking pattern is recognized and walking step is detected at easy when acceleration measurement unit is mounted on leg.. This results can be directly utilized in designing the personal navigation system with low-cost inertial sensor.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.28-31
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• 2014

This paper is concerned with the active vibration control of washing machine. To this end, a new control algorithm utilizing an acceleration signal as a sensor signal is newly developed based on the principle of a dynamic absorber. The resulting control algorithm was implemented digitally on the DSP board. The accelerometer and the active linear actuator were used as sensor and actuator for the active vibration control of washing machine. Experimental results show that the proposed control algorithm can be effectively used for a controller which uses an accelerometer.