• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.6
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• pp.77-83
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• 2003

This paper deals with a position control problem of a hydraulic proportional position control system using a nonlinear friction compensation control. As nonlinear friction, stiction and coulomb friction forces are considered and modeled as deadzone and external disturbance respectively. In order to compensate this nonlinearities, we designed the controller which is the adaptive friction compensator using discrete time Model Reference Adaptive Control method in this paper. Digital Signal Processing board is employed for data acquisition and manipulation. The experimental results show that response is slow and steady-state error cannot be compensated properly without friction compensation but this compensator is effective to obtain fast response and good steady-state response.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.4
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• pp.130-135
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• 1998

This paper deals with a position control problem of a hydraulic proportional position control system using a friction compensation control. There are many nonlinearities in hydraulic systems. With only proportional controller, response is slow and steady-state error cannot be compensated properly. Controller designed in this paper achieves fast transient response through the velocity and acceleration feedback and good steady-state response through the friction compensator. A/D and D/A board is employed for data acquisition and manipulation. The experimental results are compared with computer simulation results using Matlab.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.6
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• pp.879-884
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• 2012

Photoacoustic Tomography (PAT) is a promising medical imaging modality by reason of its particularity. It combines optical imaging contrast of optical imaging with the spatial resolution of ultrasound imaging and can demonstrate change of biological feature in an image. For that reason, many studies are in progress to apply this technic for diagnosis. But, real-time PAT system is necessary to confirm a biological reaction induced by external stimulation immediately. Thus, we developed a real-time PAT system using linear array transducer and self-developed Data acquisition board (DAQ) resources, To evaluate the feasibility and performance of our proposed system, two type of phantom test were also performed. As a result of those experiments, the proposed system shows enough performance and confirm its usefulness.

• Corrosion Science and Technology
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• v.10 no.4
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• pp.151-155
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• 2011

The iron oxide particles could be resulted from the corrosion of the circulating water system of a power plant. Because it may be one of the trouble materials which affect the power generation efficiency due to the deposition on steam generator tube and turbine blade, the continuous observation of its concentration is very important. The laser induced break-down detection (LIBD) technology was applied to monitor continuously the concentration of corrosion products with the detection limit of ppb level. The measurement system consists of a Nd:YAG pulsed laser, a polarizing beam splitter, a flow-type sample cell, an acoustic emission sensor, a high speed data acquisition board, a personal computer, etc.. The performance test results confirmed that this technology can be effective to monitor the corrosion product concentration of the circulating water system of a power plant.

• Journal of the Semiconductor & Display Technology
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• v.15 no.2
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• pp.55-60
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• 2016

This study was developed through the secondary battery module charging/discharger possible utilization in the production process equipment circuit. The developed module is ensuring construction of efficient and productive charging and discharger through this research a limit on the yield and the price of existing single -channel charge and discharger circuit as a 5V 70A grade secondary battery Formation charge and discharger for up to 1 board 4 channels. In order to improve the sensing accuracy, through a robust differential amplifier circuit described using 16bit Analog-Digital Converter and noise was secured 16bit resolution sensing. The configuration also made demands for property Rise / Fall Time. Data Acquisition, discharge efficiency and also to fit the sink circuit temperature level for mass production.

• International Journal of Railway
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• v.1 no.4
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• pp.169-174
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• 2008

Experimental study has been conducted to clarify the internal and external pressure variation characteristics for KTX(Korea Train eXpress) passing through tunnel. Abrupt pressure variation gives rise to the ear-discomfort for passenger and fatigue for car body. In this study, the internal and external pressure variation are measured by using KTX real train experiment and on-board portable data acquisition system in Gyeongbu high speed commercial line. The tunnels from 200 m to 4000 m in length are chosen for the investigation of tunnel length effects. From the results of experiment, the internal pressure variation rate for all the test tunnels is lower than the standard criteria of 200 Pa/s. And, the critical tunnel lengths for pressure wave pattern are classified into 7 groups by using the theoretical L-t diagram analysis.

• Food Science and Preservation
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• v.1 no.1
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• pp.37-43
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• 1994

A microcomputer system consisting of 16-bit microcomputer, PCL-711S interface board, censors, and converters have been set up in order to automatically measure temperature, humidity and weight loss which are major variables of storage of apple. This system was operated by PC-LabDAS software. It has been possible to measure continuously the weight loss of Fuji apple stored in CA with the weight converter made by a miniature load cell and a strain amplifier. The temperature was checked by a k-type thermocouple and Pt 100 $\Omega$ RTD, and humidity by PQ653JAl humidity sensor. It has been possible to set up a linear equation which showers high correlationship between the estimate of temperature, weight humidity and the output of the converter in that r2 is more than 0.99. Transpiration rate, a significant factor of quality deterioration for CA storage of apple, can be estimated with these values.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1454-1462
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• 2008

This paper is focused on the analysis of the noise and vibration measured near the wheelset of the high-speed trains using a time-varying frequency transform as a preliminary research of running monitoring. Due to the non-stationary characteristics, it is necessary to examine noise and vibration of the train with time-varying frequency transforms. In this paper, the short-time Fourier transform method is utilized - the stored data is localized by modulating with a window function, and Fourier transform is taken to each localized data. For the examination, the non-stationary noise and vibration of the high-speed train's wheelset are measured by using some microphones and accelerometers, and those signals are stored in a on-board data acquisition system. The non-stationary random signal analyses with the short-time Fourier transform are performed, and the result are classified as follows; auto-spectral density, cross-spectral density, frequency response, and coherence functions. From those functions, it is possible to observe the frequency characteristics of sleepers, switchers, tunnels, and steel bridges. Also, some distinct peaks, which are not dependent upon the train's speed, are identified from the results.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2373-2375
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• 2002

전자 제어식 미끄럼 방지 제동 장치(ABS, Anti-lock Brake System)를 장착한 차량의 실차 제동 시험은 시험용 차량을 비롯하여, 많은 분석장비를 필요로 한다. 이러한 고가의 장비는 구하기가 어려울 뿐만 아니라 사용방법을 학습하는 데에도 상당한 기간을 필요로 하므로, 개발중인 ABS에 대하여 적용해 보기에는 그 사용에 제약을 받는다. 본 논문에서는 개발중인 미끄럼방지 제동 알고리즘과 전자제어장치(ECU, Electronic Control Unit)를 대형 버스에 장착하여, 저 점착 노면에서 주행 시험을 시행하였고, 그 주행 기록의 분석을 위하여 DAS(Data Acquisition System)를 구현하였다. 개발 ABS 알고리즘 및 ECU의 기능과 성능 검증이 목적인 DAS는 부가적인 센서 및 고가의 장비를 사용하지 않고 제어보드와 휴대용 노트북 컴퓨터를 이용하였다. 고정밀도의 자료를 획득할 수는 없었지만, 개발 DAS를 이용한 차량 실차 제동 시험은 경제적이면서도 효과적인 ECU 및 알고리즘의 성능 분석을 이룰 수 있었다. 특히 개발 DAS는 제어 및 Data Acquisition을 동일한 보드를 사용하여 구현함으로써, ABS 장착 실차 주행 시험 결과를 제어알고리즘에 즉각적으로 반영시킨 수 있었다. 이러한 One Board System 및 On-Vehicle Programming을 이용한 방법은 개발 알고리즘의 빠른 Debugging 및 파라미터 조정(Tuning)을 가능하게 하였으므로, 실차 제동 시험을 위한 한정된 기간 내에 개발 ABS ECU 및 제어 알고리즘의 성능을 효과적으로 검증할 수 있었다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.2
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• pp.113-119
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• 2020

The IoT-based sensor network is one of the methods that can be efficiently applied to maintain the facilities, such as bridges, at a low cost. In this study, based on LoRa LPWAN, one of the IoT communications, sensor board for cable tension monitoring, data acquisition board for constructing sensor network along with existing measurement sensors, are developed to create bridge structural health monitoring system. In addition, we designed and manufactured a smart sensor node for LoRa communication and established a sensor network for monitoring. Further, we constructed a test bed at the Yeonggwang Bridge to verify the performance of the system. The test bed verification results suggested that the LoRa LPWAN-based sensor network can be applied as one of the technologies for monitoring the bridge structure soundness; this is excellent in terms of data rate, accuracy, and economy.