• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.2
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• pp.252-260
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• 1997

In this paper, a friction compensation method using a disturbance observer is proposed for an impedance control of pneumatic manipulator. It is assumed that the generated torque by a pneumatic actuator can be estimated based on the pressure signals and the discharge volume. In order to improve the dynamic characteristics of the pneumatic actuator driven by meter out method, we construct the inner torque control system by feeding back the generated torque. In order to reduce the influence of disturbances comprising friction torque and parameter variations of plant, the impedance control system is constructed with a disturbance observer which estimates the disturbances based on the generated torque of pneumatic actuator, the angular velocity and the reaction torque. From some experiments, it is confirmed that the proposed control system is effective to improve the robustness for the friction torque in the impedance control of a pneumatic manipulator.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.503-506
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• 2008

Liquid hydrocarbon fuels, such as gasoline, kerosene, diesel and JP 8, can be good candidates for SOFC (solid oxide fuel cell) system fuel due to their high hydrogen density. Autothermal reforming (ATR) is suitable for liquid hydrocarbon fuel reforming because oxygen can decompose the aromatics in liquid fuel and steam can suppress the carbon deposition during catalytic reaction. The advantage of ATR is that it has a simple system construction due to exothermicity of ATR reaction. We control the exothermicity of reaction, make the reaction possible design a self-sustaining ATR reactor. A self-sustained 1kW-class kerosene autothermal reformer is introduced in this paper. The 1kW-class kerosene reformer was continuously operated for about 140 hours without degradation of reforming performance.

• Journal of Korean Institute of Industrial Engineers
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• v.16 no.2
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• pp.11-21
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• 1990

With a general trend toward larger and more complex systems with centralized control, an operator's role of supervisory decision making in the control room becomes more important. Identification of potential man-machine interface (MMI) problems with CRT-based process control systems was attempted using a structured questionnaire survey. Based on the survey results, a laboratory experiment was carried out to investigate the performance of alarm detection on a process control CRT display. The user performance was measured in terms of reaction time from the onset of an alarm sound until the completion of predefined response procedures. The results revealed that for a highly complex tasks, mean reaction time ($\bar{RT}$) with a color consistent display was 10.5% faster than that with the original display, and $\bar{RT}$ with a grouped display was reduced by 8.2% in comparison with the color consistent display.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.3
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• pp.19-27
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• 2010

KSLV(Korea Space Launch Vehicle)-I is designed as a launch vehicle to enter a 100 kg-class satellite to the LEO(Low-Earth Orbit). Attitude angles of the upper-stage, including roll, pitch and yaw are controlled by cold gas thruster system using nitrogen gas. The thruster for the KSLV-I is the main pneumatic valve in the RCS(Reaction Control System). In this paper, the design, function tests, and environment tests of the thruster for KSLV-I are described. The developed thrusters are experimentally evaluated and successfully passed the required qualification and acceptance tests.

• International Journal of Automotive Technology
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• v.7 no.3
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• pp.315-320
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• 2006

We have developed an active front steering system(AFS) with a planetary gear train, which can vary the steering gear ratio according to the vehicle speed and improve vehicle stability by superimposing steering angle. We conducted vehicle tests showing that co-operated control of AFS with ESP can improve vehicle stability by direct control of tire slip angle and that steering reaction torque during AFS intervention can be compensated by torque compensation using electric power steering.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.4
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• pp.579-592
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• 2016

CNUSAIL-1, to be launched into low-earth orbit, is a cubesat-class satellite equipped with a $2m{\times}2m$ solar sail. One of CNUSAIL's missions is to deploy its solar sail system, thereby deorbiting the satellite, at the end of the satellite's life. This paper presents the design results of the attitude control system for CNUSAIL-1, which maintains the normal vector of the sail by a 3-axis active attitude stabilization approach. The normal vector can be aligned in two orientations: i) along the anti-nadir direction, which minimizes the aerodynamic drag during the nadir-pointing mode, or ii) along the satellite velocity vector, which maximizes the drag during the deorbiting mode. The attitude control system also includes a B-dot controller for detumbling and an eigen-axis maneuver algorithm. The actuators for the attitude control are magnetic torquers and reaction wheels. The feasibility and performance of the design are verified in high-fidelity nonlinear simulations.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.807-812
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• 2000

Chlorination dosage in water treatment plant of field is determined by chlorination demand experiment through two or three hours after raw water was sampled in inflow. It is impossible to continuously control fer real time because sampled water is adapted chlorination dosage after water treatment process had been proceeded. Therefore in this study, we will design informal chlorination demand system this designed system will be experimented as to water quality and accuracy of control in various conditions. Throughout these. experimental results, we will revise the system and revised system is enable to optimal control of chlorination dosage. Finally, We have developed chlorination demand system, which can automatically determination of chlorination dosage to be determined according to variety of raw water quality inflow in water treatment plant.

• Journal of Microbiology and Biotechnology
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• v.32 no.5
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• pp.672-679
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• 2022

Microbial lipases are used widely in the synthesis of various compounds due to their substrate specificity and position specificity. 4-Ethyl malate (4-EM) made from diethyl malate (DEM) is an important starting material used to make argon fluoride (ArF) photoresist. We tested several microbial lipases and found that Photobacterium lipolyticum M37 lipase position-specifically hydrolyzed DEM to produce 4-EM. We purified the reaction product through silica gel chromatography and confirmed that it was 4-EM through nuclear magnetic resonance analysis. To mass-produce 4-EM, DEM hydrolysis reaction was performed using an enzyme reactor system that could automatically control the temperature and pH. Effects of temperature and pH on the reaction process were investigated. As a result, 50℃ and pH 4.0 were confirmed as optimal reaction conditions, meaning that M37 was specifically an acid lipase. When the substrate concentration was increased to 6% corresponding to 0.32 M, the reaction yield reached almost 100%. When the substrate concentration was further increased to 12%, the reaction yield was 81%. This enzyme reactor system and position-specific M37 lipase can be used to mass-produce 4-EM, which is required to synthesize ArF photoresist.

• Journal of ILASS-Korea
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• v.25 no.3
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• pp.132-138
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• 2020

N₂O is hazardous atmosphere pollution matter which can damage the ozone layer and cause green house effect. There are many other nitrogen oxide emission control but N₂O has no its particular method. Preventing further environmental pollution and global warming, it is essential to control N₂O emission from industrial machines. In this study, the thermal decomposition experiment of N₂O gas mixture is conducted by using cylindrical reactor to figure out N₂O reduction and NO formation. And CHEMKIN calculation is conducted to figure out reaction rate and mechanism. Residence time of the N₂O gas in the reactor is set as experimental variable to imitate real SNCR system. As a result, most of the nitrogen components are converted into N2. Reaction rate of the N₂O gas decreases with N₂O emitted concentration. At 800℃ and 900℃, N₂O reduction variance and NO concentration are increased with residence time and temperature. However, at 1000℃, N₂O reduction variance and NO concentration are deceased in 40s due to forward reaction rate diminished and reverse reaction rate appeared.

• The Journal of Korea Robotics Society
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• v.7 no.1
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• pp.20-28
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• 2012

In spite of the difficulties and uncertain characteristic of cable driven method, surgical robot instrument has adopted it as driving mechanism for various reasons. To overcome the problem of cable system, previous research applied SMCSPO (sliding mode control with sliding perturbation observer) algorithm as robust controller to control the instrument and found that the value of SPO (sliding perturbation observer) followed force disturbance, reaction force loaded on the tip very similarly. Thus, this paper confirms that the perturbation observer is sufficient estimator which finds out the mount of loaded force on the surgical robot instrument. To prove the proposition, simulation using the similar model with an actual instrument and experimental evaluation are performed. The results show that it is possible to substitute SPO for sensors to measure the reaction force. This estimated reaction force will be used to realize haptic function by sending the reaction force to a master device for a surgeon. The results will contribute to create surgical benefit such as shortening the practice time of a surgeon and giving haptic information to surgeon by using it as haptic signal to protect an organ by making force boundary.