• Title, Summary, Keyword: Structured beam

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Robot Target Tracking Method using a Structured Laser Beam (레이저 구조광을 이용한 로봇 목표 추적 방법)

  • Kim, Jong Hyeong;Koh, Kyung-Chul
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.12
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    • pp.1067-1071
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    • 2013
  • A 3D visual sensing method using a laser structured beam is presented for robotic tracking applications in a simple and reliable manner. A cylindrical shaped laser structured beam is proposed to measure the pose and position of the target surface. When the proposed laser beam intersects on the surface along the target trajectory, an elliptic pattern is generated. Its ellipse parameters can be induced mathematically by the geometrical relationship of the sensor coordinate and target coordinate. The depth and orientation of the target surface are directly determined by the ellipse parameters. In particular, two discontinuous points on the ellipse pattern, induced by seam trajectory, indicate mathematically the 3D direction for robotic tracking. To investigate the performance of this method, experiments with a 6 axis robot system are conducted on two different types of seam trajectories. The results show that this method is very suitable for robot seam tracking applications due to its excellence in accuracy and efficiency.

Vibration Control of a Glass-Fiber Reinforced Termoplastic Composite Beam (유리섬유를 함유한 열가소성 복합재 보의 진동제어)

  • 권대규;윤여흥;이성철
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.11-14
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    • 2000
  • This paper presents the vibration control of a glass-fiber reinforced thermoplastic composite beam with a distributed PVDF sensor and piezo-ceramic achlator. The three types of different controllen which are PID, H$\infty$ , and p-synthesis ontrollcr are employed to achieve vibration suppression in the transient vibration of composite beam. In the H$\infty$ , controller design, 1st and 2nd natural frequencies are considered in the modeling, because robust control theory which has robustness to struchred uncertainty is adopled Lo suppress the vibration. If the controller designed by H$\infty$ , theory does not satisfy control performance, it is improved by $\mu$ -synthesis method with D-K iteration so that the$\mu$-contoller based on the structured singular value satisfies the nominal performance and robust performance Simulations and experiments were carried out with the designed controllers m order to demonstrate the suppression efficiency of each controller.

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Robust Control of a Glass Fiber Composite Beam using $\mu$-Synthesis Algorithm

  • Lee, Seong-cheol;Kwon, Tae-Kyu;Yun, Yeo-Hung
    • International Journal of Precision Engineering and Manufacturing
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    • v.1 no.2
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    • pp.76-83
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    • 2000
  • A study on the robust control of a composite beam with a distributed PVDF sensor and piezo-ceramic actuator is presented in this paper. $1^{st}$ and $2^{nd}$ natural frequencies are considered in the modeling, because robust control theory which has robustness to structured uncertainty is adopted to suppress the vibration. If the controllers designed by $H_{\infty}$ theory do not satisfy control performance, it is improved by $\mu$-synthesis method with D-K iteration so that the $\mu$-controller based on the structured singular value satisfies the nominal performance and robust performance. Simulation and experiment were carried out with the designed controller and the verification of the robust control properties was presented by results.

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Improvement of Proton Beam Quality from the High-intensity Short Pulse Laser Interaction with a Micro-structured Target

  • Seo, Ju-Tae;Yoo, Seung-Hoon;Pae, Ki-Hong;Hahn, Sang-June
    • Journal of the Optical Society of Korea
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    • v.13 no.1
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    • pp.22-27
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    • 2009
  • Target design study to improve the quality of an accelerated proton beam from the interaction of a high-intensity short pulse laser with an overdense plasma slab has been accomplished by using a two-dimensional, fully electromagnetic and relativistic particle-in-cell (PIC) simulation. The target consists of a thin core part and a thick peripheral part of equivalent plasma densities, while the ratio of the radius of the core part to the laser spot size, and the position of the peripheral part relative to the fixed core part were varied. The positive effects of this core-peripheral target structure could be expected from the knowledge of the typical target normal sheath acceleration (TNSA) mechanism in a laser-plasma interaction, and were apparently evidenced from the comparison with the case of a conventional simple planar target and the case of the transversal size reduction of the simple planar target. Improvements of the beam qualities including the collimation, the forward directionality, and the beam divergence were verified by detailed analysis of relativistic momentum, angular directionality, and the spatial density map of the accelerated protons.

Design of range measurement systems using a sonar and a camera (초음파 센서와 카메라를 이용한 거리측정 시스템 설계)

  • Moon, Chang-Soo;Do, Yong-Tae
    • Journal of Sensor Science and Technology
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    • v.14 no.2
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    • pp.116-124
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    • 2005
  • In this paper range measurement systems are designed using an ultrasonic sensor and a camera. An ultrasonic sensor provides the range measurement to a target quickly and simply but its low resolution is a disadvantage. We tackle this problem by employing a camera. Instead using a stereoscopic sensor, which is widely used for 3D sensing but requires a computationally intensive stereo matching, the range is measured by focusing and structured lighting. In focusing a straightforward focusing measure named as MMDH(min-max difference in histogram) is proposed and compared with existing techniques. In the method of structure lighting, light stripes projected by a beam projector are used. Compared to those using a laser beam projector, the designed system can be constructed easily in a low-budget. The system equation is derived by analysing the sensor geometry. A sensing scenario using the systems designed is in two steps. First, when better accuracy is required, measurements by ultrasonic sensing and focusing of a camera are fused by MLE(maximum likelihood estimation). Second, when the target is in a range of particular interest, a range map of the target scene is obtained by using structured lighting technique. The systems designed showed measurement accuracy up to 0.3[mm] approximately in experiments.

Vibration Control of a Intelligent Cantilevered Beam with a Distributed PVDF Sensor and PZT Actuator

  • Yun, Yeo-Hung;Kwon, Tae-Kyu;Lee, Seong-Cheol;Yu, Kee-Ho
    • 제어로봇시스템학회:학술대회논문집
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    • pp.22.5-22
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    • 2001
  • Robust control of a GFR composite beam with a distributed PVDF sensor and piezo-ceramic actuator is presented En this paper. Modal analysis method and modal coordinates are introduced to obtain the state educations of the structural system. 1st and 2nd natural frequencies are considered In the modeling, because robust control theory which is robustness to structured uncertainty is adopted to suppress the vibration. If the controllers designed by H$\^$$\infty$/ theory do not satisfy control performance, it is improved by ${\mu}$-synthesis method with D-K Iteration so that the ${\mu}$-controller based on the structured singular value satisfies the nominal performance and robust performance.

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Robust Control of a Glass-Fiber Reinforced Composite Beam using $\mu$-Synthesis Algorithm

  • Yun, Yeo-Hung;Lee, Young-Choon;Kwon, Tae-Kyu;Yu, Kee-Ho;Lee, Seong-Cheol
    • 제어로봇시스템학회:학술대회논문집
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    • pp.498-498
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    • 2000
  • A study on the robust control of a composite beam with a distributed PVDF sensor and piezo-ceramic actuator is presented in this paper. 1st and 2nd natural frequencies are considered in the modeling, because robust control theory which has robustness to structured uncertainty is adopted to suppress the vibration. If the controllers designed by H$_{\infty}$ theory do not satisfy control performance, it is improved by $\mu$-synthesis method with D-K iteration so that the $\mu$-controller based on the structured singular value satisfies the nominal performance and robust performance. Simulation and experiment were carried out with the designed controller and the verification of the robust control properties was presented by results.

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A study on based shape monitoring in HERW pipe production by using structured light beam (구조화된 직선빔을 이용한 구조파 전기 저항 용접파이프의 비드 형상 측정에 관한 연구)

  • 고국원;김종형;조형석;공원일
    • 제어로봇시스템학회:학술대회논문집
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    • pp.672-678
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    • 1993
  • The bead shape in high frequency electric resistance (HER) pipe welding gives important information ons judging current welding state. In most manufacturing process, the heat input is controlled by skilled operators observing color and bead shape. We proposed the bead shape monitoring system in HERW pipe process by using structured light beam. We reconstructs 3-D shape of bead from the measured data, and compare this shape with real 3-D shape obtained by coordinate-measuring machine. This experiment results show that the proposed system can monitor the bead shape with good accuracy.

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A 3D Foot Scanner Using Mirrors and Single Camera (거울 및 단일 카메라를 이용한 3차원 발 스캐너)

  • Chung, Seong-Youb;Park, Sang-Kun
    • Korean Journal of Computational Design and Engineering
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    • v.16 no.1
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    • pp.11-20
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    • 2011
  • A structured beam laser is often used to scan object and make 3D model. Multiple cameras are inevitable to see occluded areas, which is the main reason of the high price of the scanner. In this paper, a low cost 3D foot scanner is developed using one camera and two mirrors. The camera and two mirrors are located below and above the foot, respectively. Occluded area, which is the top of the foot, is reflected by the mirrors. Then the camera measures 3D point data of the bottom and top of the foot at the same time. Then, the whole foot model is reconstructed after symmetrical transformation of the data reflected by mirrors. The reliability of the scan data depends on the accuracy of the parameters between the camera and the laser. A calibration method is also proposed and verified by experiments. The results of the experiments show that the worst errors of the system are 2 mm along x, y, and z directions.

3D shape reconstruction using laser slit beam and image block (레이저슬릿광과 이미지블럭을 이용한 경면물체 형상측정알고리즘)

  • 곽동식;조형석;권동수
    • 제어로봇시스템학회:학술대회논문집
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    • pp.93-96
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    • 1996
  • Structured laser light is a widely used method for obtaining 3D range information in Machine Vision. However, The structured laser light method is based on assumption that the surface of objects is Lambertian. When the observed surfaces are highly specularly reflective, the laser light can be detected in various parts on the image due to a specular reflection and secondary reflection. This makes wrong range data and the image sensor unusable for the specular objects. To discriminate wrong range data from obtained image data, we have proposed a new algorithm by using the cross section of image block. To show the performance of the proposed method, a series of experiments was, carried out on: the simple geometric shaped objects. The proposed method shows a dramatic improvement of 3D range data better than the typical structured laser light method.

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