• 소음진동
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• 제4권1호
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• pp.23-31
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• 1994

When a shaft is misaligned, a high level of vibration is experienced. As a consequence, the system performance could be low with high level of noise generated. Even, a catastrophic damage of the rotating machinery may happen in the worst situation. The vibration caused by the shaft misalignment is not cured unless a correct alignment of the shaft is investigated. In this paper, a step by step approach for the turbine alignment has been demonstrated. It includes measurement tips of the coupling rim and face, calculation procedure of the bearing level, and the relevant values of the addition and subtration for shims in order to align the shaft level correctly. Then, as an application of the shaft alignment, the turbine system at the Pyung Tek focile electric power plant has been examined. Since the real system consists of high pressure, low pressure turbines and the generator, detailed alignment prolcedures of the multi stage shaft system has been demonstrated.

• 제어로봇시스템학회논문지
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• 제17권2호
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• pp.183-189
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• 2011

An alignment algorithm for strapdown inertial navigation systems is proposed, in which the psi angle error model is utilized. The proposed alignment algorithm is derived from the Psi angle error model which has been widely used in real-time navigation systems. The equation for expecting steady state alignment error is also derived. The proposed algorithm was verified through real-time experiments. Experimental results show that the proposed algorithm can be used in the inertial navigation system and GNSS/INS integrated navigation system to get an initial attitude of the vehicle.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권5호
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• pp.205-215
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• 2006

In this paper an optical power meter using Hadamard transform, which can be used in multiple channel optical elements alignment system, is proposed. A traditional optical power meter in multiple channel optical elements alignment system is able to judge how well the elements are aligned each other by measuring optical power of the first and the last two channels with at least two detectors. It has critical drawback that the alignment accuracy per channel is dependent on the number of detectors. The proposed optical power meter can get noise reduction by the Hadamard transform based multiplexing technique. The Hadamard transform based multiplexing technique using spatial light modulators is distinguished by the best enhancement of signal-to-noise ratio (SNR) for the reconstructed signals. Moreover, the noise reduction increases with increasing the order of multiplexing, namely the number of optical element channels. The proposed system is implemented by PDLC (Polymer Dispersed Liquid Crystal) mask which is operated by electric filed and generates optimal multiplexing patterns based on the Hadamard transform and single detector. It means that we obtain not only the each channel's optical power of multiple channel elements at once but also the best enhancement of SNR with single detector. Experimental results show that the proposed optical power meter is suitable for an active optical alignment system for multiple channel optical elements.

• 제어로봇시스템학회논문지
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• 제15권9호
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• pp.887-893
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• 2009

In this paper, a mask-panel alignment robot system is considered for IT industry applications. Two kinds of solutions are suggested which are required in constructing a control system for the alignment robot with actuation redundancy. First, the kinematic solution for the 4PPR parallel positioning mechanism is formulated for an arbitrary initial posture, which relates the mask-panel misalignment in the task space and the desired actuator displacements in the joint space. Secondly, in order to increase the stiffness of the control motion and also to avoid the mechanical lock which may happen due to the redundant actuation, a new synchronous control method is proposed which has the merit of coordinating joint control motions while not losing individual joint control performance. In addition, the engineering process to develop a visual alignment robot system is described with the results of experimental setup and GUI software. Finally, the experimental results demonstrate the effectiveness of the proposed alignment system control methodology and how much beneficial it will be in real industrial applications.

• 한국광학회지
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• 제4권1호
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• pp.15-21
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• 1993

본 연구에서는 설계제작된 KrF 엑시머 레이저 스텝퍼는 광원인 KrF엑시머 레이저, 조명광학계, 축소트영광학계, 정밀구동 웨이퍼 스테이지, 정렬시스템 및 이들을 제어하기 위한 제어계로 구성되어 있다. 본 실험에서 사용한 KrFdprtlaj 레이저는 밴드폭 3pm, 반복주파수 200Hz, 평균축력 3W이고, 5:1 투영렌즈는 N.A. 0.42, 전체 필드영역 $\varphi$21.2mm, 왜곡수차 최대 60nm 이하이다. 또한 정밀구동 웨이퍼 스테이지의 재현성과 해상도는 각각 $\pm$0.08$\mu\textrm{m}$/200mm(3 sigma), 100mm 반경에서 0.05 $\mu\textrm{m}$이다. 자동 초점 시스템은 $\pm$50$\mu\textrm{m}$범위에서 0.1$\mu\textrm{m}$의 해상도를 나타냈으며, 자동수평시스템은 120 arcsec 범위에서 larcsec의 해상도를 나타냈다. OFF-AXIS 정렬방식에서는 0.2$\mu\textrm{m}$의 해상도를 가지며, 두빔의 간섭을 이용한 새로운 TTL 정렬은 0.1$\mu\textrm{m}$의 해상도를 나타냈다. 스텝퍼 패턴 실험결과 SAL603레지스트를 사용하였을 때 웨이퍼의 노광후 열처리 $105^{\circ}C$, 60초에서 0.3$\mu\textrm{m}$ Lines and Spaces(L/S)까지 해상되었으며, 0.34$\mu\textrm{m}$ L/S에서 1$\mu\textrm{m}$의 초점심도를 얻을 수 있었다. 마스크 패턴과 레지스트 패턴의 선형성은 0.4$\mu\textrm{m}$ L/S가지 유지 되었다. 또한 XP-89131레지스트의 경우 노광후 열처리 $110^{\circ}C$, 60초에서 0.34$\mu\textrm{m}$ L/S까지 해상됨을 알수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권8호
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• pp.2366-2380
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• 2024

In this study, a high-speed template matching system is proposed for wafer-vision alignment. The proposed system is designed to rapidly locate markers in semiconductor equipment used for wafer-vision alignment. We optimized and implemented a template-matching algorithm for the high-speed processing of high-resolution wafer images. Owing to the simplicity of wafer markers, we removed unnecessary components in the algorithm and designed the system using a field-programmable gate array (FPGA) to implement high-speed processing. The hardware blocks were designed using the Xilinx ZCU104 board, and the pyramid and matching blocks were designed using programmable logic for accelerated operations. To validate the proposed system, we established a verification environment using stage equipment commonly used in industrial settings and reference-software-based validation frameworks. The output results from the FPGA were transmitted to the wafer-alignment controller for system verification. The proposed system reduced the data-processing time by approximately 30% and achieved a level of accuracy in detecting wafer markers that was comparable to that achieved by reference software, with minimal deviation. This system can be used to increase precision and productivity during semiconductor manufacturing processes.

• 한국공작기계학회논문집
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• 제18권1호
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• pp.83-89
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• 2009

In most multi-stage forging processes, the die spotting process or alignment of punch and die depends on the manual operation. It results a very tedious and inefficient procedure, thus the proper measurement system is needed to improve productivity and accuracy. This paper proposes a measurement system for alignment of die and punch which has a cylindrical holder, and describes the system concepts using 3 eddy-current displacement transducers and precise measurement jig. In order to apply this measurement system to real situations, the measuring procedures and system calibration method, etc. are proposed. Finally, the accuracy and productivity of this measurement system are investigated in this paper.

• Journal of Computing Science and Engineering
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• 제10권3호
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• pp.85-94
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• 2016

We propose a model-based method for information alignment using educational standards as a case study. Discrepancies and inconsistencies in educational standards across different states/cities hinder the retrieval and sharing of educational resources. Unlike existing educational standards alignment systems that only give binary judgments (either "aligned" or "not-aligned"), our proposed system classifies each pair of educational standard statements in one of seven levels of alignments: Strongly Fully-aligned, Weakly Fully-aligned, Partially-$aligned^{***}$, Partially-$aligned^{**}$, Partially-$aligned^*$, Poorly-aligned, and Not-aligned. Such a 7-level categorization extends the notion of binary alignment and provides a finer-grained system for comparing educational standards that can broaden categories of resource discovery and retrieval. This study continues our previous use of mathematics education as a domain, because of its generally unambiguous concepts. We adopt a materialization pattern (MP) model developed in our earlier work to represent each standard statement as a verb-phrase graph and a noun-phrase graph; we align a pair of statements using graph matching based on Bloom's Taxonomy, WordNet, and taxonomy of mathematics concepts. Our experiments on data sets of mathematics educational standards show that our proposed system can provide alignment results with a high degree of agreement with domain expert's judgments.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.61.2-61
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• 2001

The purpose of the initial alignment of a SDINS is to get a coordinate transformation matrix from the body frame to the navigation frame. The initial alignment is one of the most important processes in the navigation system since its error has a large influence on the navigation solution. In this paper, a real-time initial alignment algorithm for the SDINS is developed using the Kalman filter. The steady state error analysis is performed for the developed Kalman filter technique and the gyrocompass loop method. The performance of the developed alignment method is compared with the gyrocompass loop method through the real-time alignment experiments.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.26-26
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• 2000

We study on the velocity matching algorithm for transfer alignment of inertial navigation system(INS) using robust H$_2$ filter. We suggest an uncertainty model for INS and apply the suggested discrete robust H$_2$ filter to the uncertainty model compared with kalman filter, the discrete robust H$_2$ filter is shown by simulation to have good performance of alignment time and accuracy.