• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.6
• /
• pp.885-890
• /
• 2002

Turbo compressor needs high speed rotation of impeller in structure, high rated gearbox and conventional induction motor. This mechanical system increased the moment of inertia and mechanical friction loss. Resently the study of turbo compressor applied super high speed motor and drive, removing gearbox made its size small and mechanical friction loss minimum. In this study we tried to develope variable super high speed motor controller, compressor controller and MMI controller under one DSP based systems for 1500Hp, 70,000rpm direct drive Turbo compressor. It have to do unitification of each controller"s hardware and software. The result of study is applied to a 150Hp direct turbo compressor and makes it goods.oods.

• Journal of Sensor Science and Technology
• /
• v.21 no.1
• /
• pp.53-58
• /
• 2012

Biological and chemical assays(e.g., clinical tests for medical diagnosis) are needed to handle small liquid volume with high accuracy and high reliability. Many micro-dispensing systems using various actuation methods have been developed and applied. In this research, we confirm repeatability of the cartridge-type dispensing system with various measuring methods for guarantee of an acceptable reliability. We systematically examine the dispensed volume variation and dispense rate during 500,000 shots of sequential actuation. Using the same method, we confirm the repeatability of dispensed volume while varying operating conditions and design parameter(i.e., outlet size) of the dispensing system. Also, we examine the consistency of the dispensed volume of droplet while varying the operating pressures. Furthermore, we repeatedly measure differences between an actual dispensed volume and a target volume. According to our results, it is expected that the stable and reliable performance of our dispensing system can effectively be used in various applications containing bio-solutions.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.6
• /
• pp.119-128
• /
• 2001

Recently safety systems for the commercial vehicle have been rapidly developed. However, we still have many problems in the vehicle stability and the braking performance. Especially, a commercial vehicle may meet a dangerous braking condition when the vehicle is lightly loaded or empty and the road is wet or slippery. To design the air brake system for commercial vehicles, since the air brake system has many design variables, there must have been intensive researches on a method how to prevent dynamic instability and how to maximize the vehicle deceleration. In this study, mathematical models about an 8$\times$4 vehicle and an air brake system including an ABS controller have been constructed for computer simulation. Also, simple examples are applied to show the usefulness of the computer program. Designers can use this simulation program for understanding the braking characteristics of 8$\times$4 commercial vehicles such as trajectory, braking distance, longitudinal deceleration, lateral deceleration, and yaw rate on various road conditions.

• Transactions of The Korea Fluid Power Systems Society
• /
• v.5 no.4
• /
• pp.17-25
• /
• 2008

This study presents an analytical model of the pneumatic circuit of an air suspension system to analyze the characteristics of vehicle height control. The analytical model was developed through the co-simulation of Simulink(air spring) and HyPneu(pneumatic circuit). Variant effective area of air spring and flow coefficients of pneumatic valves were estimated experimentally prior to the system test, and utilized in simulation. One-comer test apparatus was established using the components of commercial air suspension products. The results of simulation and experiment were so close that the proposed analytical model in this study was validated. However the frictional loss of conduit and heat dissipation which were ignored in this study need to be considered in future study. As an application example of proposed analytical model, an alternative pneumatic circuit of air suspension to conventional WABCO circuit was evaluated. The comparison of simulation results of WABCO circuit and alternative circuit show that proposed analytical model of co-simulation in this study is useful for the study of pneumatic system of automotive air suspension.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.741-747
• /
• 2010

Vent-relief valve performed as a safety-valve combination for liquid propellant feeding system of space launch vehicle, which can vent the vaporized oxygen vapor during both filling cryogenic oxidizer into tank and flight. We have designed vent-relief model by using the AMESim code to predict dynamic characteristics and simulate pneumatic behavior of valve. To validate valve model we have compared by opening time in vent model, and opening/closing pressure by mathematical methods and improved the accuracy through numerical flow analysis by using FLUENT code. In this study, we had verified design parameters and analyzed operating performances. We can use these analysis results to precedent development study on propellant feeding system of Korea Space Launch Vehicle.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.19 no.4
• /
• pp.548-552
• /
• 2010

The air suction filter of the power plant decrease the dust and impurities of suction air that reduce the life and efficiency of the boiler. The suction efficiency of the air filter falls with the dust and impurities when the time of use comes to be long. Therefore, the various contaminant of the filter must remove periodically. This paper presents a developed quick exhaust valve to use in the thermo-electric power plant. to removing contaminants on the filter, the blowing is done shortly by air pressure. The Air flowed out to the out side from the inside of the filter. The performance test of the developed valve is done by making a test-bench according to JIS and KS standards. The efficiency is found higher than the existing related valve.

• Journal of the Semiconductor & Display Technology
• /
• v.11 no.2
• /
• pp.45-51
• /
• 2012

Multilayer co-extrusion blown film construction is a popular technique for producing plastic films for various packaging industries. Automated detection of defective films can improve the quality of film production process. In this paper, we propose a film inspection system that can detect and classify film defects robustly. In our system, first, film images are acquired through a high speed line-scan camera under an appropriate lighting system. In order to detect and classify film defects, an inspection algorithm is developed. The algorithm divides the typical film defects into two groups: intensity-based and texture-based. Intensity-based defects are classified based on geometric features. Whereas, to classify texture-based defects, a texture analysis technique based on local binary pattern (LBP) is adopted. Experimental results revealed that our film inspection system is effective in detecting and classifying defects for the multilayer co-extrusion blown film construction line.

• Journal of Korean Institute of Industrial Engineers
• /
• v.21 no.4
• /
• pp.593-608
• /
• 1995

In this study two issues are considered, one is to develop a pneumatic servomechanism using a direct-connected circuit between inlet and outlet, the other is to design two kinds of advanced controllers such as fuzzy and PID controllers for a fingering system. Besides, the application of the advanced controllers to the newly proposed servomechanism is presented. The procedure of this study is composed of following 6 steps : [Step 1] Structuring of a control system; [Step 2] Development of a pneumatic circuit for the servomechanism ; [Step 3] Characteristic analysis of the valve and cylinder systems ; [Step 4] Determination of optimal parameters of the PID controller ; [Step 5] Design of a fuzzy controller and parameter tuning; and, [Step 6] Experimental analysis of fuzzy and PID controllers. Experimental results show that the newly proposed pneumatic servomechanism has good performance and, not only the performance of the fuzzy controller is better than that of the PID controller but also the fuzzy controller fits well to the control of the pneumatic servomechanism.

• Journal of Power System Engineering
• /
• v.10 no.4
• /
• pp.56-64
• /
• 2006

This paper shows the development process of a straight-type five-hole pressure probe for measuring three-dimensional flow velocity components. The data reduction method using a bi-cubic curve-fitting program in a new calibration map was introduced in this study. This new calibration map can be applied up to the application angle, ${\pm}55^{\circ}$ of a probe. As a result, for the application angle of ${\pm}45^{\circ}$, an error for yaw and pitch angles appeared from $-1.76^{\circ}\;to\;1.83^{\circ}$ and from $-1.91^{\circ}\;to\;1.75^{\circ}$, respectively. Moreover, an error for a vector magnitude and a static pressure compared with a dynamic one showed from -7.83% to 4.87% and from -0.73 to 0.77, respectively. Even though this data reduction method showed unsatisfactory errors in a vector magnitude, it resulted in an easy and simple application method. Especially, when it was applied to an actual flow field including a swirling flow, a good result came out on the whole. However, in order to obtain a better result, it is thought that a more sophisticated interpolation method needs to be introduced.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.2
• /
• pp.101-106
• /
• 2021

In this paper, an inspection system has been developed where pneumatic instruments are used to stretch the film using compressed air, thus the curl problem can be overcome. When the pneumatic system is applied, a line scan camera should be used instead of an area camera because the COF surface makes an arc by the air pressure. The distance between the COF and the inspection camera should be kept constant to get a clear image, thus the position of COF is to be monitored on real-time. An operating software has been also developed which is switching on/off the pneumatic system, determining the COF position using a camera vision, displaying the contour of the COF side view, sending self-diagnosis result and etc. The developed system has been examined using the actual roll of COF, which convince that the system can be an effective device to inspect the COF rolls in process.