• Title/Summary/Keyword: 반경오차

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A Study on the Reduction of Navigation Error for Cleaning Robot (청소로봇의 주행오차 저감에 관한 연구)

  • No, Yong-Jun;Jung, Kwang-Sik;Kim, Myoung-Jun;Lim, Young-Cheol;Ryoo, Young-Jae
    • Proceedings of the KIEE Conference
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    • 2002.07d
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    • pp.2503-2506
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    • 2002
  • 본 논문에서는 청소로봇의 주행에 관해 연구되어지고 있는 이론적인 제어알고리즘이 갖는 주행오차저감방법에 관해 연구하였다. 청소로봇의 양 바퀴의 속도에 따라 그려지는 이상적인 회전반경과 실제 실험을 통해 그려지는 회전반경은 다르다. 이는 청소로봇이 주행 시 나타나는 오차가 원인이다. 많은 이론적인 제어알고리즘이 청소로봇의 주행에 잘 적용되기 위해 주행 시 나타나는 오차를 수정하거나 보상해야 한다. 본 연구에서는 이상적인 회전반경과 실험을 통해 얻은 회전반경의 비교를 통해 오차와 회전반경을 구하고 이를 주행에 적용하고자 한다.

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Blind adaptive equalizations using the multi-stage radius-directed algorithm in QAM data communications (QAM 시스템에서 다단계 반경-지향 알고리듬을 이용한 블라인드 적응 등화)

  • 이영조;임승주;이재용;강창언
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.9
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    • pp.1957-1967
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    • 1997
  • Adaptive channel equlization accomplished without resorting to a training sequence is known as blind equalization. In this paper, in order to reduce the speed of the convergence and the steady-state mean squared error simultaneously, we propose the multi-stage RD(radius-directed) algorithm derived from the combination of the constant modulus algorithm and the radius-directed algorithm. In the starting stage, multi-stage RD algorithm are identical to the constant modulus algorithm which guarantees the convergence of the equalizer. As the blind identical to the constant modulus algorithm which guarantees the convergence of the equalizer. As the blind equalizer converges, the number of the level of the quantizers is increased gradually, so that the proposed algorithm operate identical to the radius-directed algorithm which leads to the low error power after the covnergence. Therefore, the multi-stage RD algorithm obtains fast convergence rage and low steady stage mean square error.

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Study on the Correction of a Wing-tail Interference Effect in a Semi-empirical Aerodynamic Analysis Tool (반경험적 공력 해석도구의 주날개-꼬리날개 간섭 효과 보정에 대한 연구)

  • Lee, Dae-Yeon;Kim, Jae-Hyun;Kang, Dong-Gi
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.49 no.2
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    • pp.85-93
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    • 2021
  • In this paper, the aerodynamic characteristics of general tail controlled missile were predicted and corrected the result using semi-empirical analysis tool. The cause of the error was confirmed by comparing the aerodynamic characteristics prediction result of the semi-empirical analysis tool with the wind tunnel test result, and the main error factor of the semi-empirical analysis tool was the interference component between the main wing and the tail wing. The semi-empirical analysis results were corrected using the wind tunnel test results and the computational analysis results, and it was confirmed that the corrected data agrees well with the wind tunnel test results. Through this study, it was confirmed that the wing-tail interference component correction is needed when predicting the aerodynamic characteristics of a general tail controlled missile using a semi-empirical analysis tool.

Optimal Parameter Tuning to Compensate for Radius Errors (반경오차 보정을 위한 최적파라미터 튜닝)

  • 김민석
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.04a
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    • pp.629-634
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    • 2000
  • Generally, the accuracy of motion control systems is strongly influenced by both the mechanical characteristics and servo characteristics of feed drive systems. In the fed drive systems of machine tools that consist of mechanical parts and electrical parts, a torsional vibration is often generated because of its elastic elements in torque transmission. Especially, a torsional vibration caused by the elasticity of mechanical elements might deteriorate the quick movement of system and lead to shorten the life time of the mechanical transmission elements. So it is necessary to analyze the electromechanical system mathematically to optimize the dynamic characteristics of the feed drive system. In this paper, based on the simplifies feed drive system model, radius errors due to position gain mismatch and servo response characteristic have been developed and an optimal criterion for tuning the gain of speed controller is discussed. The proportional and integral parameter gain of the feed drive controller are optimal design variables for the gain tuning of PI speed controller. Through the optimization problem formulation, both proportional and integral parameter are optimally tuned so as to compensate the radius errors by using the genetic algorithm. As a result, higher performance on circular profile tests has been achieved than the one with standard parameters.

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Analysis of radial error motion in a small-sized and high-speed spindle (소형-고속 스핀들의 반경방향 오차분석 방법)

  • 이응삼;이재하;양승한
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.604-608
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    • 2004
  • In this paper, an efficient method is proposed to analyze the radial error of a miniaturized-high speed spindle system. Initially, a device is constructed for measuring the radial error motion using capacitance sensors. The capacitance sensors are placed perpendicular to the axis of the shaft and at 90o to each other. The spindle is rotated at high speed and the profile of the spindle is recorded. An algorithm is developed for analyzing the spindle data and determining the radial error of spindle. The present algorithm uses homogeneous transform matrix (HTM) method and iterative process for determining the radial error. The analysis procedure is performed for different speeds of the spindle. The data obtained from the present system and the results of evaluation are also presented in this paper. It is observed that this method is effective in determining and analyzing the spindle errors for high speed miniaturized spindle.

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Performance Evaluation of Radial Error of a Rotary Table at Five-axis Machine Tool (5축 공작기계에서 회전 테이블의 반경 오차 성능 평가)

  • Lee, Kwang-Il;Yang, Seung-Han
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.2
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    • pp.208-213
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    • 2012
  • In this paper, the radial error of a rotary table at five-axis machine tool is evaluated by utilizing ISO 230-2 and estimation method using double ball-bar. The geometric error of a rotary table is defined as position dependent geometric errors or position independent geometric errors according to their physical character. Then estimation method of geometric errors using double ball-bar is simply summarized including measurement path, parametric modeling and least squares approach. To estimate representative radial error, offset error, set-up error which affect to the double ball-bar data, mean value of measured data including CCW/CW-direction are used at estimation process. Radial errors are separated from measured data and used for evaluation with ISO 230-2. Finally, suggested evaluation method is applied to a rotary table at five-axis machine tool and its result is analyzed to improve the accuracy of the rotary table.

Improved method of lateral offset calculation for optical waveguide (광도파로의 곡률 반경에 따른 모드특성과 Lateral Offset 변화)

  • 박순룡;김우택;라상호;오범환
    • Korean Journal of Optics and Photonics
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    • v.9 no.6
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    • pp.408-412
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    • 1998
  • As the radius of curvature of curved optical waveguide gets smaller, the loss increases at the junction of linear-curved waveguide by the cross sectional mode mismatch. The concept of lateral offset has been used widely to minimize it, and simple method of maximum matching has been efficient for most cases of silica waveguide with low optical confinement and large radius of curvature. Here, we analyzed that the propagation mode characteristics of the lateral offset and propagation mode characteristics of general case with effective index method and Airy function solution. As the normalized frequency varies, mode characteristics changes near the boundary of 1/V=0.7 and the simple matching of gaussian profile might give -35% of error at most. We proposed improved method with a new correction factor to improve the mode mismatch problem of conventional methods for general cases, and showed the convenience and feasibility of this method for the calculation of the lateral offset.

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Forest Thematic Maps and Forest Statistics Using the k-Nearest Neighbor Technique for Pyeongchang-Gun, Gangwon-Do (kNN 기법을 이용한 강원도 평창군의 산림 주제도 작성과 산림통계량 추정)

  • Yim, Jong-Su;Kong, Gee Su;Kim, Sung Ho;Shin, Man Yong
    • Journal of Korean Society of Forest Science
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    • v.96 no.3
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    • pp.259-268
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    • 2007
  • This study was conducted to produce forest thematic maps and estimate forest statistics for Pyeongchang Gun using the kNN technique, which has been applied to produce thematic maps of variables of interest including unobserved plots by combining field plot data, remotely sensed data and other digital map data in forest inventories. The estimation errors for three horizontal reference areas (HRAs), whose radii are 20, 40 and 60 km respectively, were compared. Although the precision for the 40 km radius was lower compared to that for the 60 km radius, the 40 km radius was found to be an efficient HRA because their difference in precision was modest. At a value of k=5 nearest neighbors for the selected HRA, the overall accuracy was high. As a result, using the k=5 neighbors within the HRA of 40 km radius, thematic maps of number of trees, basal area, and growing stock per hectare were generated. As compared to the forest statistics based on field sample plots, the estimated means of each parameter from the produced maps were underestimated.

NC 공작기계 컨투어 운동 정도의 해석

  • 박준호
    • Journal of the KSME
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    • v.32 no.5
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    • pp.441-455
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    • 1992
  • NC 공작기계의 운동정밀도는 키네마틱 트랜스듀서 링크 컨투어 측정시스템(Kinematic transducer link contour measuring system), BDD 측정시스템, Circular Test 등에 의해 측정될 수 있으며, 오차 발생원인을 규명할 수 있다. 이 글에서는 NC 공작기계의 오차가 컨투어 시험 결과에 미치는 영향을 평가하기 위하여, 공칭원(nominal circle) 혹은 공칭호(nominal arc)로부 터의 반경방향 편위를 포함하는 컨투어 운동결과를 이론적으로 해석하였다.

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On the Generalized Empirical Equation for Effective Wellbore Radius (유효우물반경 산정 경험공식의 일반화에 대하여)

  • Choi, Byong-Soo
    • Journal of Soil and Groundwater Environment
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    • v.13 no.3
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    • pp.15-20
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    • 2008
  • The investigation on the previous paper(Jn. of KoSSGE vol.12, no.3), which proposed three empirical equations for the different aquifers was carried out. To draw out a single equation from the three different equations the mean value of the involution factors was adopted allowing different proportional coefficients for the different aquifers. On the other hand it was found that the square root value of storativity ratio, ${\sqrt{{S_p}/{S_o}}}$ in each well is almost equal to its wellbore radius ratio, ${r_e}/{r_w}$. From this fact, the proportional coefficients can be substituted with assumed aquifer storativity and a generalized empirical equation for the effective wellbore radius has been derived.