• Title/Summary/Keyword: Air disturbance

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Design of Robust Controller for Electromagnetic Suspension System with Kalman Filter (칼만 필터를 이용한 자기부상 시스템의 강인제어기 설계)

  • Jang, S.M.;Sung, S.Y.;Sung, H.K.;Jo, H.J.
    • Proceedings of the KIEE Conference
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    • 2000.07b
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    • pp.1411-1413
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    • 2000
  • Distubance of air-gap sensors by rail irregularities are the serious problem deteriorating the performance in the electromagnetic suspension (EMS) systems. Thus, this paper proposes the output feedback controller with discrete kalman filter for the EMS systems. The discrete kalman filter estimate true state value and output feedback controller guarantee stability. The benefit of this scheme are shown by simulation. Therefore air-gap disturbance are rejected successfully.

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Development of Automobile Air Conditioner Controller based on the Fuzzy Logic (퍼지논리를 이용한 차량용 공조제어기 개발에 관한 연구)

  • Lee, Yong-Joong;Lee, Un-Kun;Lee, Yang-Bum
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.1323-1326
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    • 1996
  • This paper describes an air conditioner control method using a fuzzy control theory. The fuzzy control method was implemented with Philips 80C552 one chip microcomputer and tested in an actual vehicle. Experiments showed that proposed control method is superior to the conventional PID control method especially in the environments with abrupt disturbance and parameter variation of the control system. Fuzzy-Based control method was proved to maintain a stable and improved temperature control in an abrupt environmental changes.

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Numerical Simulation of Air Flows in Human Upper Airway for Free Flap Reconstruction Following Resection Surgery in Oral Cancer Patients (구강암 절제 및 재건 수술에 따른 기도 내 공기 유동 시뮬레이션)

  • Seo, Heerim;Song, Jae Min;Yeom, Eunseop
    • Journal of the Korean Society of Visualization
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    • v.18 no.3
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    • pp.96-102
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    • 2020
  • Oral cancer surgery changes the morphologic characteristics of the human upper airway. These changes can affect the flow patterns. In this study, computational fluid dynamics (CFD) simulations with transient solver were performed to numerically investigate the air flows in the human upper airways depending oral cancer surgery. 3D reconstructed models were obtained from 2D CT images of one patient. For the boundary condition, the realistic breathing cycle of human was applied. The hydraulic diameters of cross-sections for post-surgical model are changed greatly along streamwise direction, so these variations can cause higher wall shear stress and flow disturbance compared to pre-surgical model. The recirculation flows observed in the protruding region result in the relatively large pressure drop. These results can be helpful to understand the flow variations after resection surgery of oral cancer.

Basic Study on the Performance of a Pressure-difference Control Damper Affected by Flow Disturbance in a Wind Tunnel (풍도 내 유동 교란과 자동차압 댐퍼의 성능 특성 기초 연구)

  • Yun, Yung-Min;Lee, Min-Jung;Kim, Nam-Il;Ryou, Hong-Sun
    • Fire Science and Engineering
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    • v.23 no.6
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    • pp.16-23
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    • 2009
  • The performance characteristics of a smoke damper, which aims to suppress the penetration of smoke to a safe area, have been tested under the regulation of the FIS 001. However, the improvement of the test methods and the regulation has consecutively been requested. From a view-point of fluid mechanical theory, a pressure control damper, that is installed at the end of the flow control system, is important and it dominates flow characteristics in all designed flow systems. In this study, the weak points of the regulation of the FIS 001 concerned with the pressure control damper was visited and the some important characteristics of the damper was examined. Based on these results, it was confirmed that the effects of flow disturbance in the air supplying duct on the performance of the damper are not significant. This results gives some information for the modification of the experimental regulation concerned to the pressure control damper.

An Electro-magnetic Air Spring for Vibration Control in Semiconductor Manufacturing (반도체 생산에서 진동 제어를 위한 전자기 에어 스프링)

  • Kim, Hyung-Tae;Kim, Cheol-Ho;Lee, Kang-Won;Lee, Gyu-Seop;Son, Sung-Wan
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.12
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    • pp.1128-1138
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    • 2010
  • One of the typical problems in the precise vibration is resonance characteristics at low frequency disturbance due to a heavy mass. An electro-magnetic(EM) air spring is a kind of vibration control unit and active isolator. The EM air spring in this study aims at removing the low frequency resonance for semiconductor manufacturing. The mechanical and electronic parts in the active isolator are designed to operate under a weight of 2.5 tons. The EM spring is floated using air pressure in a pneumatic elastic chamber and actuated by EM levitation force. The actuator consists of a EM coil and a permanent magnetic plate which are installed inside of the chamber. An air mount was constructed for the experiment with a stone surface plate, 4 active air springs, 4 gap sensors, a DSP controller, and a multi-channel power amp. A PD control method and operating logic was applied to the DSP. Simulation using 1/4 model was carried out and compared with the experiments. The time duration and maximum peak at resonance frequency can be reduced sharply by the proposed system. The results show that the active system can avoid the resonance caused by the natural frequency of the passive system.

Analysis of Load Value acting Free Falling Object according to Disturbance using Nonlinear Load Control Model (비선형 하중 제어 모델에서 외란에 따른 자유낙하 물체에 작용하는 하중값 분석)

  • Wang, Hyeon-Min;Woo, Kwang-Joon
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.47 no.2
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    • pp.55-59
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    • 2010
  • Recently it is tried to use load control model for maneuver moving object. MIN design method proposed to solve control problem of nonlinear system using load concept. The Min design method shows direct method for finding control value on the load control model. In this paper, is shown realization free falling model using nonlinear load control model and analysis of load values acting falling object according to disturbance. And made a trajectory according to acting load values due to disturbance. This paper's result is able to be applied to design algorithm for improvement accuracy of MLRS, GPS air-to-surface missile(ASM) and returning spacecraft with nonlinear model predictive control.

A Study on the Classification of Nursing Diagnoses by Student Nurses (간호학생이 내린 간호진단 분석에 관한 연구)

  • Min, Soon
    • Journal of Korean Academy of Nursing
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    • v.25 no.3
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    • pp.457-471
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    • 1995
  • This research was done to promote improvement of practical application of nursing diagnoses and to improve the quality of nursing. The subjects of this research were 156 second year students of C junior nursing college who were giving adult patient care. The nursing diagnoses of 312 reports were analyzed using NANDA. In these case reports only nursing diagnoses were considered, of which there were a total of 982. In the data analysis the 9H of the nursing students' nursing diagnoses matched with 105 NANDA nursing diagnoses, Of these, the most frequent diagnoses were pain(165, 17.48%), anxiety(101, 10.70%), alteration in nutrition(83, 8.79%) , sleep disturbance (67, 7.10%), in activity intolerance (67, 7.10%), ineffective breathing pattern(51,5.40%). The etiology for the students' nursing diagnoses were compared with NANDA's nursing diagnoses by frequency. The most frequent etiology for the nursing diagnoses of pain was a biological etiology(50, 31%), for anxiety, situation crisis(58, 57.43%), for alteration in nutrition, indigesion(23, 27.71%), for sleep disturbance, external etiology(25, 37.32%), for activity intolerance, immobile position(22, 32.84%), for ineffective breathing pattern, pain(35, 68.63%), and for ,impaired physical mobility, pain(31, 65.96%). The most frequent etiology for constipation was inadquate digestion of water and cellulose (16, 34.78%), for fluid volume felicity, loss of body fluid (21, 52.50%), for impaired skin integrity, external etilogy(16, 43.24%), for impaired physical mobility, pain(22, 62.86%) , for knowledge deficits, cognition disturbance(9, 27.27%), for ineffective air way clearance, secretion obstruction(14, 48.27%) , for impaired gas exchange, loss of transport ability of blood oxygen(9, 37.50%) , and for powerlessness, therapy environment (5, 22.73%). The number of nursing diagnoses by pattern was exchange(16), moving(6), feeling(4), choosing(4), relating(3), communication(1), perceiving(1), knowing(1), valuing(1).

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Design the Autopilot System of using Fuzzy Algoritim

  • Kim, Young-Hwi;Bae, Gyu-Han;Park, Jae-Hyung;Kang, Sin-Chool;Lee, Ihn-Yong;Lim, Young-Do
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.296-300
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    • 2003
  • The autopilot system targets decreasing labor, working environment improvement, service safety security and elevation of service efficiency. Ultimate purpose is minimizing number of crew for guarantee economical efficiency of shipping service. Recently, being achieving research about Course Keeping Control, Track Keeping Control, Roll-Rudder Stabilization. Dynamic Ship Positioning and Automatic Mooring Control etc. which compensate nonlinear characteristic using optimizing control technique. And application research is progressing using real ship on actual field. Relation of Rudder angle which adjusted by Steering Machine and ship-heading angle are non-linear. And Load Condition of ship as non-linear element that influence to Parameter of ship. Also, because the speed of a current and direction of waves, velocity and quantity of wind etc. that is disturbance act in non-linear from, become factor who make serv ice of shipping painfully. Therefore, service system of shipping requires robust control algorithm that can overcome nonlinearity. In this paper, Using fuzzy algorithm ,Design autopilot system of ship that could overcome the non-linear factor of ship and disturbance and examined result through simulation.

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Analyses of the Heavy Snowfall Event Occurred over the Middle Part of the Korean Peninsula on March 4, 2004 and Suggestions for the Future Forecast (2004년 3월 4일 대설 사례에 관한 분석과 예보를 위한 제안)

  • Cho, Ik-Hyun;Yoo, Hee-Dong;Lee, Woo-Jin;Shin, Kyung-Sup
    • Atmosphere
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    • v.14 no.3
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    • pp.3-18
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    • 2004
  • A heavy snowfall event occurred over the middle part of the Korean peninsula on March 4, 2004. The numerical models of KMA failed to forecast this heavy snowfall event because this event was due to small scale disturbance by low lever convergence and atmospheric instability. The analyses for this heavy snowfall have been performed to give forecasters useful suggestions for forecasting heavy snowfall events in the future. The analyses for the snowfall event were recounted by the Hourly Korean Peninsula Analysis Weather Chart (HKPAWC) presenting on the KMA intranet system. We confirmed that warm air flows of low level into south central Korea in conjunction with strong southwesterly winds played important role in the heavy snowfall event. We suggested several check points to improve the forecast of heavy snowfall events in the future through the results of the analyses.

An Autonomous Blimp for the Wall Following Control

  • Oh, Seung-Yong;Roh, Chi-Won;Kang, Sung-Chul;Kim, Eun-Tai
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.1668-1672
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    • 2005
  • This paper presents the wall following control of a small indoor airship (blimp). The purpose of the wall following control is that a blimp maintains its position and pose and flies along the wall. A blimp has great inertia and it is affected by temperature, atmospheric pressure, disturbance and air flow around blimp. In order to fly indoors, a volume of blimp should be small. The volume of a blimp becomes small then the buoyancy of a blimp should be smaller. Therefore, it is difficult to attach additional equipments on the blimp which are necessary to control blimp. For these reasons, it is difficult to control the pose and position of the blimp during the wall following. In our research, to cope with its defects, we developed new blimp. Generally, a blimp is controlled by using rudders and elevators, however our developed blimp has no rudders and elevators, and it has faster responses than general blimps. Our developed blimp is designed to smoothly follow the wall by using low-cost small ultra sonic sensors instead of high-cost sensors. Finally, the controller is designed to robustly control the pose and position of the blimp which could control in spite of arbitrary disturbance during the wall following, and the effectiveness of the controller is verified by experiment.

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