• Title/Summary/Keyword: Open Loop

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Design and Structural Analysis on the Open and Close Hinge for Complex Machine (복합기 커버 개폐용 힌지의 설계와 구조 해석)

  • Yun, Yeo-Kwon;Yang, Kwang-Mo;Kim, Do-Seok
    • Journal of the Korea Safety Management & Science
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    • v.14 no.2
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    • pp.49-54
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    • 2012
  • As all kind of industry has developed, metal structure and machine instrument use bolt, pin, rivet and welding for assembly and combination. For pin and hinge, dimension accuracy is crucial to keep the operation and safety of the structure and machine instrument. In case of complex machine, the hinge for cover open-loop system is one of the significant design elements. Most of the hinges are being imported and assembled sine they give high technology development cost for its unit cost position. The reason is that the localization of hinge is inadequate. As the demand increase and the necessity of localization grow, it is now more important than ever to develop low cost structure. By the low cost structure, a new technology could be obtained for electronic product and structural hinge since it would enable for complex machine hinge to be guaranteed, technologically. Open-loop hinge is the link type and designed for the structure to keep constant open-loop. And, the hinge is examined in design stability by finite element analysis method. In this paper, the operation result is presented when the hinge for complex machine open-loop is designed for link type structure.

Implementation of a Low-cost Fiber Optic Gyroscope for a Line-of-Sight Stabilization System (Line-of-Sight 안정화 시스템을 위한 저가형 광자이로스코프 구현)

  • Yoon, Yeong Gyoo;Lee, Sang-Min;Kim, Jae Hyung
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.2
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    • pp.168-172
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    • 2015
  • In general, open-loop fiber-optic gyroscopes (FOG) are less stable than closed-loop FOGs but they offer simpler implementation. The typical operation time of line-of-sight (LOS) stabilization systems is a few seconds to one hour. In this paper, a open-loop fiber optic gyroscope (FOG) for LOS applications is designed and implemented. The design goal is aimed at implementing a low cost, compact FOG with low Angle Random Walk (ARW) (< $0.03deg/\sqrt{h}$) and bias instability (< 0.25deg/h). The FOG uses an open-loop all-fiber configuration with 100M PM fiber wound on a small diameter spool. In order to get the design goal, digital signal processing techniques for signal detection, modulation control and compensation are designed and implemented in FPGA.

An offset algorithm with forward tracing of tangential circle for open and closed poly-line segment sequence curve (접원의 전방향 경로이동에 의한 오프셋 알고리즘)

  • Yun, Seong-Yong;Kim, Il-Hwan
    • Proceedings of the KIEE Conference
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    • 2003.11c
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    • pp.1022-1030
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    • 2003
  • In this paper we propose a efficient offset curve construction algorithm for $C^0$-continuous Open and Closed 2D sequence curve with line segment in the plane. One of the most difficult problems of offset construction is the loop problem caused by the interference of offset curve segments. Prior work[1-10] eliminates the formation of local self-intersection loop before constructing a intermediate(or raw) offset curve, whereas the global self-intersection loop are detected and removed explicitly(such as a sweep algorithm[13]) after constructing a intermediate offset curve. we propose an algorithm which removes global as well as local intersection loop without making a intermediate offset curve by forward tracing of tangential circle. Offset of both open and closed poly-line segment sequence curve in the plane constructs using the proposed approach.

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Open-loop Wavefront Correction Based on SH-U-net for Retinal Imaging System

  • Ming Hu;Lifa Hu;Hongyan Wang;Qi Zhang;Xingyu Xu;Lin Yu;Jingjing Wu;Yang Huang
    • Current Optics and Photonics
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    • v.8 no.2
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    • pp.183-191
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    • 2024
  • High-resolution retinal imaging based on adaptive optics (AO) is important for early diagnosis related to retinal diseases. However, in practical applications, closed-loop AO correction takes a relatively long time, and traditional open-loop correction methods have low accuracy in correction, leading to unsatisfactory imaging results. In this paper, a SH-U-net-based open-loop AO wavefront correction method is presented for a retinal AO imaging system. The SH-U-net builds a mathematical model of the entire AO system through data training, and the Root mean square (RMS) of the distorted wavefront is 0.08λ after correction in the simulation. Furthermore, it has been validated in experiments. The method improves the accuracy of wavefront correction and shortens the correction time.

A digital closed-loop processor with a stabilizer for an open-loop fiber-optic gyroscope (개회로 FOG용 폐회로 신호처리기의 안정화)

  • 김도익;예윤해
    • Korean Journal of Optics and Photonics
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    • v.13 no.5
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    • pp.377-383
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    • 2002
  • An all-digital closed-loop (ADCL) signal processor for an open-loop FOG was developed to replace the analog circuitry of a Digital Phase Tracking (DPT) signal processor with new digital circuitry. When the ADCL signal processor without a stabilizer for fiber phase modulator (FPM) was attached to the FOG, temperature drift of FOG was about 0.26$\mu$rad/$^{\circ}C$, which makes the FOG unusable in medium or higher-grade applications. This drift was due to variations of phase modulation amplitude and phase delay of the FPM. The stabilizer controls its phase modulation amplitude and phase delay by regulating the ratio of harmonics of the FOG output. Thus, the stabilizer reduces the drift of the FOG to negligible.

Active Window system based on Finite Thickness Window Model (유한 두께 창문 모델을 적용한 능동 소음제어 창문)

  • Kwon, Byoung-Ho;Park, Young-Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.04a
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    • pp.763-768
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    • 2012
  • Active window system which can reduce the environmental noises, such as traffic noise and construction noise, from an open window into a room was proposed in the previous works. The key idea of the proposed active window system was that the control sources are approximately collocated with the primary noise source in terms of the acoustic power for global noise reduction throughout the interior room. Moreover, because it is important not to intrude into the living space in the building environment, no error sensors were used and an open-loop control method using control sources at the window frame and the reference sensors outside the room was used for the proposed system. The open-loop control gain was calculated by the interior room model assumed as the semi-infinite space, and the interior sound field was estimated by Rayleigh integral equation under the baffled window model assumption. However, windows with a finite thickness should were considered for the calculation of the open-loop control gain of the active window system since these are representative of most window cases. Therefore, the finite thickness window model based on the Sgard's model was derived and the open-loop control gain using the interior sound field estimated by that model was calculated for active window system. To compare the performance of these two models, a scale-model experiment was performed in an anechoic chamber according to noise source directions. Experimental results showed that the performance for the thickness window model is better than the baffled window model as the angle with respect to the perpendicular direction is larger.

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Feedback Control for Expanding Range and Improving Linearity of Microaccelerometers

  • Park, Yong-Hwa;Shim, Joon-Sub;Park, Sang-Jun;Kwak, Dong-Hun;Ko, Hyoung-Ho;Song, Tae-Yong;Huh, Kun-Soo;Park, Jahang-Hyon;Cho, Dong-Il
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.1706-1710
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    • 2004
  • This paper presents a feedback-controlled, MEMS-fabricated microaccelerometer (${\mu}$XL). The ${\mu}$XL has received much commercial attraction, but its performance is generally limited. To improve the open-loop performance, a feedback controller is designed and experimentally evaluated. The feedback controller is applied to the x/y-axis ${\mu}$XL fabricated by sacrificial bulk micromachining (SBM) process. Even though the resolution of the closed-loop system is slightly worse than open-loop system, the bandwidth, linearity, and bias stability are significantly improved. The noise equivalent resolution of open-loop system is 0.615 mg and that of closed-loop system is 0.864 mg. The bandwidths of open-loop and closed-loop system are over 100 Hz. The input range, non-linearity and bias stability are improved from ${\pm}$10 g to ${\pm}$18 g, from 11.1 %FSO to 0.86 %FSO, and from 0.221 mg to 0.128 mg by feedback control, respectively

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A Study on Position of Six-Degrees-of-Freedom of vibration Model and Orientation Decision by Adaptive Control Method (6자유도 진동모댈의 위치 및 자세결정을 위한 적응제어기법의 적용에 관한 연구)

  • Kim, J.Y.;Song, S.K.;Han, J.H.;Oh, Y.H.;Cho, S.H.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.6
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    • pp.94-101
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    • 1994
  • About vibration model of Six-degrees-of-freedom(DOF), in mass load, examined results for knowing dynamic interference and response variation is as follows; In case of putting mass load upon the object, experimented results on two-degrees-of-freedom of the translation-1 direction and the rotation-1 direction at open-loop-control system, about 0.19 arcsed in input of the translation-$0.1{\mu}m$ and $0.022{\mu}m$ on input of the rotation-0.5 arcsec, the justicse of motion equation is acknowledged as confirming the appearance of the interference-$0.022{\mu}m$. In establishing calculation of transformation matrix by using analogue circuit, as simulating results that used incomplete differentiation, interference is $1.7{\times}10^{-3}$ arcsec on input of the translation-$0.1{\mu}m$ and $1.4{\times}10^{4}{\mu}m$ on input of the rotation-0.5 arcsec in open-loop-control system. Also it is $4.2{\times}10^{-4}$ arcsec on input of the translation-$0.1{\mu}m$ and $5.6{\times}10^{-5}{\mu}m$ on input of the rotation-0.5 arcesc in closed-loop-control system. As closed-loop-control system is better than open-loop-control system, equivalent accordance is confirmed on original response. Finally, fundamental validity of this theory is acknowledged.

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HARDWARE IN THE LOOP SIMULATION OF HYBRID VEHICLE FOR OPTIMAL ENGINE OPERATION BY CVT RATIO CONTROL

  • Yeo, H.;Song, C.H.;Kim, C.S.;Kim, H.S.
    • International Journal of Automotive Technology
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    • v.5 no.3
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    • pp.201-208
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    • 2004
  • Response characteristics of the CVT system for a parallel hybrid electric vehicle (HEV) are investigated. From the experiment, CVT ratio control algorithm for the optimal engine operation is obtained. To investigate the effect of the CVT system dynamic characteristics on the HEV performance, a hardware in the loop simulation (HILS) is performed. In the HILS, hardwares of the CVT belt-pulley and hydraulic control valves are used. It is found that the engine performance by the open loop CVT ratio control shows some deviation from the OOL in spite of the RCVs open loop control ability. To improve the engine performance, a closed loop control of the CVT ratio is proposed with variable control gains depending on the shift direction and the CVT speed ratio range by considering the nonlinear characteristics of the RCV and CVT belt-pulley dynamics. The HILS results show that the engine performance is improved by the closed loop control showing the operation trajectory close to the OOL.

Design of Closed Loop Pipe Cooling System (냉각수 순환 형태의 파이프 쿨링 공법의 설계)

  • 박찬규;왕인수;구자중
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2001.11a
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    • pp.52-57
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    • 2001
  • In order to control hydration heat in mass concrete, pipe cooling method has been widely used. The pipe cooling method leads to the decrease of curing period by lagging materials as well as the decrease of temperature difference between center and surface of mass concrete member, There are two methods in the pipe cooling system, which are open loop system and closed loop system. However open loop pipe cooling system cannot be applied to the mass concrete structures when cooling water supply is difficult. To control hydration heat of high strength mass foundation in the central area of city, closed loop pipe cooling system was developed to solve the cooling water supply. This paper reports the performance results of hydration heat control with closed loop pipe cooling system.

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