• Title/Summary/Keyword: corner point

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Study on the Appearance Spring back of Spinning Process (스피닝 공정에서의 스프링백 현상에 관한 연구)

  • 박중언;이우영;최석우;나경환;김승수
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.05a
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    • pp.837-841
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    • 2000
  • Spinning process is a chipless metal forming method for axi-symmetric parts, which is more economical, efficient and versatile method of producing parts than the other sheet metal forming process such as stamping or deep drawing. It is a point deformation process where a metal disc. cylinderical workpiece. or preform in contact with a rotating chuck is plastically deformed by axial or axial-radial Motions of a tool or roller. in this study the variation of spring back with respect to various forming roller corner radius(Rr) and angle of roller holder($\alpha$) is investigated. Good as a result will help to get more precise shape by control of spring back.

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A Study on the Edge Following of Task Object by Industrial Robot Using F/T Sensor (F/T Sensor를 이용한 산업용 로봇에 의한 물체 선단추적에 관한 연구)

  • 최성락;정광조
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.1
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    • pp.26-34
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    • 1998
  • In this paper, a force control algorithm for edge following task is suggested. Through the contact state modeling between rigid part and end-effector of robot, contact force and contact angle that are essencial parameters to build the control strategies for following movement of end-effector are derived. From these two parameters, we discriminate the every contact state into 8 cases and calculate the new moving position and direction simply. For the experiment. RX90 robot from Staubli with robot language V$^{+}$ is applied and F/T sensor is attached to the wrist of robot with RCC. Finally, 3 edge following experiments including the following of corner point are executed with successful results.s.

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Vision-Based Indoor Localization Using Artificial Landmarks and Natural Features on the Ceiling with Optical Flow and a Kalman Filter

  • Rusdinar, Angga;Kim, Sungshin
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.13 no.2
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    • pp.133-139
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    • 2013
  • This paper proposes a vision-based indoor localization method for autonomous vehicles. A single upward-facing digital camera was mounted on an autonomous vehicle and used as a vision sensor to identify artificial landmarks and any natural corner features. An interest point detector was used to find the natural features. Using an optical flow detection algorithm, information related to the direction and vehicle translation was defined. This information was used to track the vehicle movements. Random noise related to uneven light disrupted the calculation of the vehicle translation. Thus, to estimate the vehicle translation, a Kalman filter was used to calculate the vehicle position. These algorithms were tested on a vehicle in a real environment. The image processing method could recognize the landmarks precisely, while the Kalman filter algorithm could estimate the vehicle's position accurately. The experimental results confirmed that the proposed approaches can be implemented in practical situations.

High Frequency Impedance Calculation of Grounding Meshes Installed at Power Substations (전력용 변전소에 설치된 메쉬 접지망의 고주파 임피던스 계산)

  • Han, Poong;Choi, Chang-Hyek
    • Proceedings of the KIEE Conference
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    • 1998.07e
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    • pp.1578-1582
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    • 1998
  • The ground potential rise generated by the switching surge or lightning stroke may be dangerous to personnel and cause damage to electronic control parts. For a first step to the transient performance analysis. high frequency impedances of grounding grids have been calculated and discussed. Grounding grids include 7 square grids from $10m{\times}10m$ to $80m{\times}80m$. The high frequency current was injected into the center and a corner of the grounding grid. The calculation results indicate that the impedance of the grounding grid is significantly influenced by frequency and the point of injection of the current. and the effective radius of a large grounding grid may be represented in $15{\sim}20m$.

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Content-Based Image Retrieval using Scale-Space Theory (Scale-Space 이론에 기초한 내용 기반 영상 검색)

  • 오정범;문영식
    • Journal of KIISE:Software and Applications
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    • v.26 no.1
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    • pp.150-150
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    • 1999
  • In this paper, a content-based image retrieval scheme based on scale-space theory is proposed. The existing methods using scale-space theory consider all scales for image retrieval,thereby requiring a lot of computation. To overcome this problem, the proposed algorithm utilizes amodified histogram intersection method to select candidate images from database. The relative scalebetween a query image and a candidate image is calculated by the ratio of histograms. Feature pointsare extracted from the candidates using a corner detection algorithm. The feature vector for eachfeature point is composed of RGB color components and differential invariants. For computing thesimilarity between a query image and a candidate image, the euclidean distance measure is used. Theproposed image retrieval method has been applied to various images and the performance improvementover the existing methods has been verified.

Finding locating checker board using corner detection and interpolation (교점의 추정 및 보간을 이용한 체커보드 검출)

  • Oh, Sang-yup;Cho, Nam-ik
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2016.11a
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    • pp.165-168
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    • 2016
  • 카메라 캘리브레이션은 실제 세상인 3차원의 좌표와 카메라가 만든 영상의 2차원 좌표 사이에서 수학적 관계를 알기 위해서 필요하다. 보통 체커보드의 교점을 이용하여 2차원의 좌표를 정확하게 찾는데 사용하며, 이는 카메라 캘리브레이션 계산으로 응용된다. 따라서 체커보드의 교점을 정확하게 찾아야만 카메라 캘리브레이션이 정상적인 성능을 낼 수 있다. 현존하는 체커보드 검출 방법은 입력 인수를 많이 필요로 하거나 정확도가 낮아 체커보드의 교점을 정확히 입력하지 못하면 좋지 않은 결과가 나타난다. 따라서 체커보드를 자동으로 검출하여 카메라 캘리브레이션 하는 방법은 아직 신뢰도가 낮은 편이다. 본 논문에서는 보다 안정적인 카메라 캘리브레이션을 위해서 체커 보드의 검출 성능을 높이고자 한다. 주위 픽셀들간의 미분 값을 기준삼아 검출된 교점들을 이용하여 체크 모양의 직선을 추측한다. 이 직선을 이용하면 장애물이 있거나 노이즈가 있어서 검출하기 어려운 교점들이 있는 경우에도 교점 보간 (point interpolation) 방법을 사용하여 나머지 교점들을 찾을 수 있다. 보간 과정을 통해서 검출에 방해가 되는 요소들이 있는 상황에서 체커 보드 교점 검출의 성능을 높이도록 하였다.

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Design of Distributed Beamforming for Dual-Hop Multiple-Access Relay Networks

  • Liu, Binyue
    • ETRI Journal
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    • v.36 no.4
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    • pp.625-634
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    • 2014
  • This paper studies a dual-hop multiple-access relay network where two independent source nodes transmit information to a common destination node with the aid of multiple single-antenna amplify-and-forward relays. Each relay node is subject to an individual power constraint. We focus on the design of distributed beamforming schemes for the relays to support the transmission rate requirements of the two sources. To this end, we first characterize the achievable rate region for this network via solving a sequence of corner point optimization problems proposed in this paper. We also develop several low-complexity suboptimal schemes in closed form. Two inner bounds of the achievable rate region are theoretically shown to be approximately optimal in two special scenarios. Finally, numerical results demonstrate the effectiveness of our proposed approaches.

Measurement and Analysis for Radar Glint Effect of Maritime Target (해상표적에 대한 레이더 Glint 영향 측정 및 분석)

  • Kim, Eunil
    • Journal of the Korea Institute of Military Science and Technology
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    • v.17 no.4
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    • pp.521-530
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    • 2014
  • In this paper, the glint effect of maritime target to a radar system was analyzed by simulation and field test with a barge and corner reflectors. From the experiment, we proposed a glint measurement method of a real maritime target and it was indicated that the glint effect between the simulation results and real measurement is similar. Also it was founded that the glint effect is related to the relative amount of RCS(Radar Cross Section) difference among major scattering point and minor scattering points. Finally, the experiment showed the glint effects of the rotating barge with some different combinations of scattering points.

A Study on the Optimal Location of the Inclinometer and Strain Gauge in Small-Scale Underground Excavation (소규모 지하굴착에서 지중경사계와 변형률계의 최적 위치 선정에 대한 연구)

  • Gichun Kang;Jinuk Park;Byeongjin Roh;Jiahao Sun;Seong-Kyu Yun
    • Journal of the Korean Geosynthetics Society
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    • v.22 no.2
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    • pp.23-33
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    • 2023
  • Currently, there are cases in Korea where economic damage has occurred due to the ambiguity instrument installation and operation standards in the construction of temporary earth retaining wall, failing to prevent collapse of temporary earth retaining wall at the construction site in advance. Therefore, in this study, a numerical analysis was conducted to find the appropriate installation location of the inclinometer and strain gauge among the installed instruments shown in the design drawing of the temporary earth retaining wall. As a results, It was found that the installation position of the underground inclinometer is the corner of the retaining wall in the case of plane-deformation analysis, and the most displacement occurs in the center of the excavation surface in the case of 3D analysis. When the stress and moment are comprehensively analyzed, the corner is judged to be a vulnerable point. In the case of the strain gauge, In plane-deformation analysis and 3D analysis, the maximum bending stress occurred at the wale connection where the end of the strut and the counter strut are in contact. At this point, it is analyzed that it is necessary to focus on installing and managing the connection to prevent accidents from being vulnerable.

Planar Curve Smoothing with Individual Weighted Averaging (개별적 가중치 평균을 이용한 2차원 곡선의 스무딩)

  • Lyu, Sungpil
    • Journal of KIISE
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    • v.44 no.11
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    • pp.1194-1208
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    • 2017
  • A traditional average smoothing method is designed for smoothing out noise, which, however, unintentionally results in smooth corner points on the curvature accompanied with a shrinkage of curves. In this paper, we propose a novel curve smoothing method via polygonal approximation of the input curve. The proposed method determines the smoothing weight for each point of the input curve based on the angle and approximation error between the approximated polygon and the input curve. The weight constrains a displacement of the point after smoothing not to significantly exceed the average noise error of the region. In the experiment, we observed that the resulting smoothed curve is close to the original curve since the point moves toward the average position of the noise after smoothing. As an application to digital cartography, for the same amount of smoothing, the proposed method yields a less area reduction even on small curve segments than the existing smoothing methods.