• Title/Summary/Keyword: 반복위치결정정도

Search Result 14, Processing Time 0.039 seconds

A Study on the Development of Small Size Three-Axis Stacker Crane for Automatic Ware House (소형 자동차고용 3축 Stacker crane 개발에 관한 연구)

  • Kim, J.Y.;Sim, J.K.;Kim, H.S.;Han, J.H.
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.12 no.8
    • /
    • pp.131-139
    • /
    • 1995
  • In this study, small size stacker Crane for automatic ware house and interface circuit is designed and manufactured. IBM-PC is used as a controller. At 50kg$_{f}$ load, optimal motion velocity is 20 mm/min for X and Y axis and 12 mm/min for Z axis. Position fesolution is 0.005 mm and repeatability is .+-. 0.025 mm. Through characteristic experiment, effectiveness of the designed and manufactured stacker crane. PC control program, and design of interface circuit and construction of control system are shown. From these results, the developed stacker crane can be apply to FMS(Flexible Manufacturing System) and FA(Factory Automation) of industrial field.d.

  • PDF

Regularized Adaptive High-Resolution Image Reconstruction (부정확한 부화소 단위의 위치 추정 오류에 적응적인 정규화된 고해상도 영상 재구성 연구)

  • Byun, Min;Lee, Eun-Sil;Kang, Moon-Gil
    • Proceedings of the Korean Society of Broadcast Engineers Conference
    • /
    • 2002.11a
    • /
    • pp.49-55
    • /
    • 2002
  • 기존의 영상 획득 시스템들이 어느 정도의 엘리어싱을 허용하도록 제작되어왔음에도 불구하고, 고해상도 영상에 대한 요구는 점점 더 증가하고 있다. 본 논문에서는 부정확한 부화소 단위의 위치추정 오류를 고려한 고해상도 재구성 알고리즘을 제안한다. 부정확한 부화소 위치 추정 오류로 인해 생기는 불량위치문제(ill-posedness)를 해결하기 위해 정규화된 반복 연산법을 적용하였다. 특히 여러장의 저해상도 영상들을 개별적으로 고려하기에 적합한 다중채널 영상 재구성 방법을 도입하였다. 각 저해상도 영상에서 발생하는 움직임 추정오류는 서로 다른 경향성을 나타내므로, 정규화 파라미터들은 각 채널에 맞게 결정되어야 한다. 이를 위채 정규화 파라미터들을 자동으로 결정하는 방법을 제안한다. 제안한 알고리즘은 움직임 추정 오류에 매우 안정하며, 원 영상과 잡음에 대한 사전정보를 필요로 하지 않는다. 또한 주관적인 측면과 객관적인 측면에서 모두 우수한 결과를 실험적으로 보인다.

  • PDF

A Study on the Improvement of Positioning accuracy of ultra-precision stage (초정밀스테이지의 위치결정정도 향상에 관한 연구)

  • 황주호;송창규;박천홍;이찬홍
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2001.04a
    • /
    • pp.465-468
    • /
    • 2001
  • An aerostatic stage has frictionless behavior, so it has a advantage of investigation into positioning characteristics. A one-dimensional aerostatic ceramic stage with ballscrew driven and laser scale feedback system is manufactured, aiming at investigating positioning characteristic of ultra-precision stage. We confirm, this ceramic aerostatic stage has a 10nm micro resolution, and can be reduced mean of position error by compensation of numeric control command. By means of analyzing relationship of position error and change of temperature, we build a on-line compensation algorithm of position error from the measured temperature data. So we can improve repeatability of ultra-precision stage up to 34%($0.095{\mu}$) of the normal condition.

  • PDF

Analysis and compensation of positioning error for aerostatic stage (공기정합 스테이지의 위치결정오차 분석 및 보정)

  • 황주호;박천홍;이찬흥;김승우
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2002.05a
    • /
    • pp.378-391
    • /
    • 2002
  • A 250mm stroke aerostatic stage, which detects position with laser scale and is driven by linear motor, is made and analyzed positioning error in 20$\pm$ 0.5 $^{\circ}C$ controlled atmosphere, aiming at investigating positioning characteristic of ultra-precision stage. We prove this aerostatic stage has a 10nm micro step resolution by experiment. By means of analyzing laser interferometer system, the scale of measuring error is about 0.2-0.4$\mu\textrm{m}$ according to refractive index error from missing the temperature change. To improve laser interferometer system, compensate refractive index error using measuring data from thermocouple. And, confirm 0.10$\mu\textrm{m}$ repeatability and 0.13 $\mu\textrm{m}$ positioning accuracy using the compensating refractive index. Also, we confirm 0.07 ${\mu}{\textrm}{m}$ repeatability of the stage using capacitive displacement sensor.

  • PDF

A New Algorithm for Determination of Reference Phases in Phase-Shifting Interferometry (위상변이간섭법에서 기준위상 결정을 위한 새로운 알고리즘 개발)

  • 한건수
    • Korean Journal of Optics and Photonics
    • /
    • v.4 no.4
    • /
    • pp.397-402
    • /
    • 1993
  • This paper presents a new computational algorithm of phase-shifting interferometry which can effectively eliminate the uncertainty errors of the reference phases encountered in obtaining multiple interferograms. The algorithm treats the reference phases as additional unknowns and determines their exact values by analyzing interferograms using numerical least square technique. A series of simulations prove that this algorithm can improve measuring accuracy being unaffected by the nonlinear and random errors of phase-shifters.

  • PDF

Regularized Adaptive High-resolution Image Reconstruction Considering Inaccurate Subpixel Registration (부정확한 부화소 단위의 위치 추정 오류에 적응적인 정규화된 고해상도 영상 재구성 연구)

  • Lee, Eun-Sil;Byun, Min;Kang, Moon-Gi
    • Journal of Broadcast Engineering
    • /
    • v.8 no.1
    • /
    • pp.19-29
    • /
    • 2003
  • The demand for high-resolution images is gradually increasing, whereas many imaging systems yield aliased and undersampled images during image acquisition. In this paper, we propose a high-resolution image reconstruction algorithm considering inaccurate subpixel registration. A regularized Iterative reconstruction algorithm is adopted to overcome the ill-posedness problem resulting from inaccurate subpixel registration. In particular, we use multichannel image reconstruction algorithms suitable for application with multiframe environments. Since the registration error in each low-resolution has a different pattern, the regularization parameters are determined adaptively for each channel. We propose a methods for estimating the regularization parameter automatically. The preposed algorithm are robust against the registration error noise. and they do not require any prior information about the original image or the registration error process. Experimental results indicate that the proposed algorithms outperform conventional approaches in terms of both objective measurements and visual evaluation.

A Study of Aerodynamic Design of a Radial Turbine for BOP of MCFC Fuel Cell System (연료전지 BOP용 구심터빈 공력설계에 관한 연구)

  • Choi, Bum-Seog;Ahn, Kook-Young;Park, Moo-Ryong
    • 유체기계공업학회:학술대회논문집
    • /
    • 2006.08a
    • /
    • pp.531-534
    • /
    • 2006
  • This study is concerned with radial turbine design and performance improvement of a turbo generator system, which is used for maximizing performance of a 250kW MCFC fuel cell system. A preliminary design of a radial turbine has been performed under the thermodynamic and fluid-dynamic conditions determined by a cycle analysis of the MCFC BOP system. Basic demensions are determined by a meanline analysis and calculation of radial variation at the exit of the turbine. The turbine impeller is designed and modified by iterative processes of three dimensional flow analysis.

  • PDF

OSCILLATIONS OF THE OUTER BOUNDARY OF THE OUTER RADIATION BELT DURING SAWTOOTH OSCILLATIONS (SAWTOOTH 진동 중에 발생한 바깥 방사선 벨트 외경계면 진동)

  • Kim Jae-Hun;Kim Kyung-Chan;Lee Dae-Young;Kim Hee-Jeong
    • Journal of Astronomy and Space Sciences
    • /
    • v.23 no.3
    • /
    • pp.217-226
    • /
    • 2006
  • We report three sawtooth oscillation events observed at geosynchronous orbit where we find quasi-periodic (every 2-3 hours) sudden flux increases followed by slow flux decreases at the energy levels of ${\sim}50-400keV$. For these three sawtooth events, we have examined variations of the outer boundary of the outer radiation belt. In order to determine L values of the outer boundary, we have used data of relativistic electron flux observed by the SAMPEX satellite. We find that the outer boundary of the outer radiation belt oscillates periodically being consistent with sawtooth oscillation phases. Specifically, the outer boundary of the outer radiation belt expands (namely, the boundary L value increases) following the sawtooth particle flux enhancement of each tooth, and then contracts (namely, the boundary L value decreases) while the sawtooth flux decreases gradually until the next flux enhancement. On the other hand, it is repeatedly seen that the asymmetry of the magnetic field intensity between dayside and nightside decreases (increases) due to the dipolarization (the stretching) on the nightside as the sawtooth flux increases (decreases). This implies that the periodic magnetic field variations during the sawtooth oscillations are likely responsible for the expansion-contraction oscillations of the outer boundary of the outer radiation belt.

Inkjet 공정에서 발생하는 TIPS Pentacene Crystalline Morphology 변화에 따른 OTFT 특성 연구

  • Kim, Gyo-Hyeok;Seong, Si-Hyeon;Jeong, Il-Seop
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2013.02a
    • /
    • pp.379-379
    • /
    • 2013
  • 본 논문에서는 Normal ink jetting 공법으로 OTFT를 제작할 때 coffee stain effect에 의해서 반도체 소자의 특성이 저하되는 것을 극복하기 위해서 동일한 위치에 동일한 부피로 Droplet을 형성하는 Multiple ink jetting 공법을 통해 TIPS pentacene 결정의 Morphology와 전기적 특성이 어떻게 변화하는지 알아 보았다. Multiple ink jetting의 drop 횟수가 증가할수록 coffee stain effect에 의해서 형성된 가운데 영역의 Dendrite grain이 점점 작아지다가 7 Drops 이후로는 Big grain 만 남게 되었다. Active layer의 표면 Roughness는 drop 횟수가 증가할수록 낮아지다가 일정 count 이후로는 다시 높아지는 것을 확인할 수 있었다. 전계 이동도(mobility)는 drop 횟수가 증가할수록 커지다가 일정 count 이후로는 saturation되는 것을 확인할 수 있었다. Multiple ink jetting에 의해서 만들어진 OTFT 소자의 전계 이동도(mobility)는 1 drop과 10 drops에서 각각 0.0059, 0.036 cm2/Vs 로 6배 정도 차이가 있었다. 이것은 첫 drop에 의해 만들어진 가운데 Dendrite grain 영역이 Multiple ink jetting을 반복하면서 점점 작아지게 되어 사라지고 두꺼운 Grain 영역만 남게 된 것으로 판단된다. Vth 와 On/Off ratio는 1 drop과 10 drops에서 각각 -3 V, -2 V 그리고 $3.3{\times}10^3$, $1.0{\times}10^4$를 보였다. OTFT의 substrate로 Flexible한 polyethersulfone (PES) 기판을 사용하였고, 절연체로 Spin coating된 Poly-4-vinylphenol (PVP)가 사용되었으며, Gate 및 Source/Drain 전극은 Au를 50 nm 두께로 증착하였다. Channel의 width와 length는 각각 100 um, 40 um 였고, Gate 전극 위에 Active layer를 형성한 Bottom gate 구조로 제작되었다. Ink jet으로 제작된 TIPS pentacene의 결정성은 x-ray diffraction (XRD)와 광학 현미경으로 분석하였고 Thickness profile은 알파스텝 측정기를 이용하였으며, OTFT의 전기적 특성은 Keithley-4,200을 사용하여 측정하였다.

  • PDF

Ablation Rate and Intrapulpal Temperature by Addition of Water Spray During Er:YAG Laser Irradiation (Er:YAG laser를 이용한 치아삭제시 물분사량이 삭제율과 치수내 온도변화에 미치는 영향)

  • Kim, Jung-Moon;Kim, Mee-Eun;Kim, Ki-Suk
    • Journal of Oral Medicine and Pain
    • /
    • v.30 no.3
    • /
    • pp.375-381
    • /
    • 2005
  • Er:YAG laser has been considered a promising alternative to dental drill and many researches indicate that adjustment to variable parameters, including water flow rate, pulse energy and pulse repetition rate, can be made to improve ablation ability and efficiency of the laser. Of these parameters, addition of water spray during irradiation has been thought to ablate dental hard tissue more rapidly and safely. The purpose of this study was to investigate tooth ablation amount by Er:YAG laser irradiation as related to varied water flow rates added and, ultimately to find the most effective water flow rate for ablation. In addition, the temperature change of pulp chamber during irradiation was also monitored on the irradiated and opposite pulpal walls, respectively. An Er:YAG laser with contact mode was employed. Extracted human molars were split into two pieces for ablation experiment. Pulse energies of 200 and 300 mJ with a pulse repetition rate of 20 Hz and 5 water flow rates (1.6, 3.0, 5.0, 7.0, and 10.0 ml/min) were applied. Each irradiation was performed for 3 seconds. According to these parameters, experimental groups were divided into 10 subgroups which consisted of 5 specimens. For temperature experiment, another 5 tooth-specimens were prepared in the manner that pulp chamber was open through access cavity preparation and two temperature-measuring probes were placed respectively on the irradiated and the opposite walls of pulp chamber. From the experiment on ablation amount related to different water flow rates, it was shown that the least water flow rate of 1.6 ml/min ablated more than any other water flow rates (p<0.000). When the irradiation for 3 seconds, combined with the pulse repetition time of 20Hz and the water flow rate of 1.6 ml/min was done to tooth specimen, the temperature rise was not noticeable both on the irradiated and the opposite pulpal walls (less than 3$^{\circ}C$) and there was no significant difference in temperature rise between the two pulse energies, 200 and 300 mJ. From the results of this study, it is suggested that tooth ablation with Er:YAG laser can be done effectively and safely at a energy between 200 and 300 mJ/pulse and a pulse repetition rate of 20 Hz when the lasing is conjugated with the water flow rate of 1.6ml/min.