• Title/Summary/Keyword: second-order system

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An Integrated System of EWMA and EPC Using Second-order Autoregressed Model in the Process with Trend (추세가 있는 공정에서 이계자기회귀 모형을 이용한 EPC와 EWMA의 통합시스템)

  • Jung Hae Woon
    • Journal of the Korea Safety Management & Science
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    • v.7 no.2
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    • pp.141-151
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    • 2005
  • EPC seeks to minimize variability by transferring the output variable to a related process input(controllable) variable, while SPC seeks to reduce variability by detecting and eliminating assignable causes of variation. In the case of product control, a very reasonable objective is to try to minimize the variance of the output deviations from the target or set point. We consider an alternative EPC model with second-order autoregressive disturbance. We compare three control systems; EPC, EPC combined with EWMA. This paper shows through simulation that tlhe performance of the integrated model of EPC and EWMA is more preferable than that of EPC.

A Study on the Second-order Iterative Learning Control Algorithm with Feedback (궤환을 갖는 2차 반복 학습제어 알고리즘에 관한 연구)

  • Huh, Kyung-Moo
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.5
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    • pp.629-635
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    • 1999
  • A second-order iterative learning control algorithm with feedback is proposed in this paper, in which a feedback term is added in the learning control scheme for the enhancement of convergence speed and robustness to disturbances or system parameter variations. The convergence proof of the proposed algorithm is givenl, and the sufficient condition for the convergence of the algorithm is provided. And it also includes the discussions about the convergence performance of the algorithm when the initial condition at the beginning of each iteration differs from the previous value of the initial. Simulation results show the validity and efficiency of the proposed algorithm.

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FLL Control for Gird Cynchronization of Distributed Power System under LVRT Control (LVRT 제어시 분산전원의 계통 동기화를 위한 FLL 제어)

  • Jang, Mi-Geum;Choi, Jung-Sik;Oh, Seung-Yeol;Song, Sung-Geun;Chung, Dong-Hwa
    • Proceedings of the KIPE Conference
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    • 2012.07a
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    • pp.494-495
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    • 2012
  • 본 논문은 LVRT 제어를 위한 계통 사고 상황에서도 정확한 위상각을 검출하기 위하여 일반화된 2차 적분기(Second Order Generalized Integrator)를 이용한 정상분 전압 검출을 기반으로 하며, 주파수 변동에도 강인성 제어가 가능한 DSOGI (Double Second Order Generalized Integrator) FLL(Frequency locked loop)을 제안한다. 실험을 통해 종래의 SRF(Synchronous reference frame) PLL, DSOGI PLL 제어와 비교, 분석을 통해 본 논문의 타당성을 입증한다.

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Computations of the Supersonic Ejector Flows with the Second Throat (2차목을 가지는 초음속 이젝터 유동에 관한 수치계산)

  • Choi, Bo-Gyu;Lee, Young-Ki;Kim, Heuy-Dong;Kim, Duck-Jool
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.8
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    • pp.1128-1138
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    • 2000
  • Pumping action in ejector systems is generally achieved through the mixing of a high-velocity and high-energy stream with a lower-velocity and lower-energy stream within a duct. The design and performance evaluation of the ejector systems has developed as a combination of scale-model experiments, empiricism and theoretical analyses applicable only to very simplified configurations, because of the generic complexity of the flow phenomena. In order to predict the detailed performance characteristics of such systems, the flow phenomena throughout the operating regimes of the ejector system should be fully understood. This paper presents the computational results for the two-dimensional supersonic ejector system with a second throat. The numerical simulations are based on a fully implicit finite volume scheme of the compressible Reynolds-averaged Navier-Stokes equation in a domain that extends from the stagnation chamber to the diffuser exit. For a wide range of the operating pressure ratio the flow field inside the ejector system is investigated in detail. The results show that the supersonic ejector systems have an optimal throat area for the operating pressure ratio to be minimized.

Life cycle cost analysis and smart operation mode of ground source heat pump system

  • Yoon, Seok;Lee, Seung-Rae
    • Smart Structures and Systems
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    • v.16 no.4
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    • pp.743-758
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    • 2015
  • This paper presents an advanced life cycle cost (LCC) analysis of a ground source heat pump (GSHP) system and suggests a smart operation mode with a thermal performance test (TPT) and an energy pile system constructed on the site of the Incheon International Airport (IIA). First, an economic analysis of the GSHP system was conducted for the second passenger terminal of the IIA considering actual influencing factors such as government support and the residual value of the equipment. The analysis results showed that the economic efficiency of the GSHP system could be increased owing to several influential factors. Second, a multiple regression analysis was conducted using different independent variables in order to analyze the influence indices with regard to the LCC results. Every independent index, in this case the initial construction cost, lifespan of the equipment, discount rate and the amount of price inflation can affect the LCC results. Third, a GSHP system using an energy pile was installed on the site of the construction laboratory institute of the IIA. TPTs of W-shape and spiral-coil-type GHEs were conducted in continuous and intermittent operation modes, respectively, prior to system operation of the energy pile. A cooling GSHP system in the energy pile was operated in both the continuous and intermittent modes, and the LCC was calculated. Furthermore, the smart operation mode and LCC were analyzed considering the application of a thermal storage tank.

Thrust Measurement System for High Altitude Simulation Test of the KSLV-I Kick Motor (KSLV-I 킥모터 개발을 위한 고공환경모사시험용 추력측정장치)

  • Lee, Jung-Ho;Cho, Sang-Yeon;Cho, Kie-Joo;Jung, Dong-Ho;Lee, Han-Ju;Oh, Seung-Hyub;Yoon, Kyung-Youl;Kim, Dong-Cheol
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.428-431
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    • 2008
  • Korea Aerospace Research Institute(KARI) is achieving the Korea Space Launch Vehicle(KSLV) program according to National Space Technology Development Program. KSLV-I will be composed to liquid propellant(first stage) and solid propellant(second stage) propulsion system. The propulsion system of KSLV-I second stage is solid kick motor with high expansion ratio and its starting altitude is 300km high. In order to verify the performance of upper stage propulsion system designed to operate in the upper atmosphere, test facility which can simulate high altitude is needed. High Altitude Simulation Test Facility is composed to Thrust Measurement System, Control & Measurement system, Diffuser, SKID for cooling water supply to diffuser, CCTV, fire protection system and so on. This paper introduces TMS adapted to High Altitude Simulation Test for KSLV-I Kick Motor Development and results of hot firing test for its performance verification.

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PC-based low speed control of a servo motor using instantaneous speed detection (PC 기반의 순시속도 검출에 의한 서보 모터의 저속 제어)

  • 류재규;박정일;이석규
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.377-382
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    • 1993
  • The low speed control of a servo motor using instantaneous speed detection method is described. To estimate the instantaneous speed from the average speed, the speed estimator of the first or second order is used. We confirm that these estimatorsimprove the speed control performance of a servo system with experiments.

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Adaptive Control of Nonminimum Phase System (비 최소치목 시스템의 적의 연구)

  • Si-Chul Roh
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.35 no.11
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    • pp.529-534
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    • 1986
  • In recent year, there have been much techniques for designing globally stable adaptive control systems when the unknown plant is minimum phase. This paper presents a new seheme for indirect adaptive control structure for nonminimum phase plant of which parameters are estimated from the least-square algorithm. Its effectiveness has been demonstrated by computer simulation carried out for a second-order plant.

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ENGINEERED SURFACE CONTROL IN TURNING PROCESS (선삭에서의 가공 표면 제어)

  • 홍민성
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.4 no.3
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    • pp.48-57
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    • 1995
  • The feasibility of generating controller surface topographies in single-point conventional turning operations is investigated. First, a mathematical model of the surface generation process was developed. Second, in order to control the texture of the machined surface, a micro-positioning stage and the associated command generation software were designed and built. Experimental examples have shown that surface texture can be precisely controlled and is in good agrement with the theoretical predictions.

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