• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.584-587
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• 2002

A vision sensor measure range data using laser light source. This sensor generally use patterned laser which shaped single line. But this vision sensor cannot satisfy new trend which needs laster and more precise processing. The sensor's sampling rate increases as reduced image processing time. However, the sampling rate can not over 30fps, because a camera has mechanical sampling limit. If we use multi line laser pattern, we will measure multi range data in one image. In the case of using same sampling rate camera, number of 2D range data profile in one second is directly proportional to laser line's number. For example, the vision sensor using 5 laser lines can sample 150 profiles per second in best condition.

• 한국정보통신학회논문지
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• 제6권8호
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• pp.1374-1380
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• 2002

용접을 하는데 있어서 보다 균일한 용접상태를 유지하고, 용접품질의 향상 및 동일시간에 보다 많은 용접을 함으로써 생산성 향상을 위해 로봇의 이용이 점차로 증가하고 있다. 로봇용접의 과정 중 실제 용접을 실시하기 위해 로봇을 움직이기 이전에 용접할 부위의 검출이 선행되어야 하고, 그 검출방법에 있어서 크게 접촉식과 비접촉식의 센서가 활용이 되고 있다. 본 논문에서는 비접촉식 중 비전센서인 레이저 다이오드와 CCD 카메라를 이용하여 CCD 카메라를 거친 영상을 처리하여 용접선을 추적하고 용접을 하도록 하고 있다. 레이저 다이오드를 용접모재와 일정 각도를 가지도록 조사하게 되면 모재표면의 형상에 따라 반사되는 굴곡면이 달라지게 되는데 이 형상이 CCD 카메라를 통해 입력되고, 이 입력된 화상을 이미지 보드와 프로그램을 통하여 분석을 하고, 얻어진 용접선의 화상의 좌표 값을 토대로 로봇을 이동시킴으로써 용접을 하도록 하고 있다. 용접은 실시간으로 이루어짐으로써 생산성 향상에 크게 기여할 수 있다. 또한 모재에 따라 굴곡이 다른 1차원 평면의 용접인 경우는 약간의 프로그램 수정으로 대부분 추적 가능하다는 것을 확인할 수 있었다.

• 한국레이저가공학회지
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• 제13권2호
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• pp.17-23
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• 2010

It is very important to track a complicate weld seam for the welding automation. Very recently, laser vision sensor becomes a useful sensing tool to find the seams. Until now, however studies of welding automation using a laser vision sensor, focused on either image processing or feature recognition from CCD camera. Even though it is possible to use a simple algorithm for tracking a simple seam, it is extremely difficult to develop a seam-tracking algorithm when the seam is more complex. To overcome these difficulties, this study introduces a simulation system to develop the seam tracking algorithm. This method was verified experimentally to reduce the time and effort to develop the seam tracking algorithm, and to implement the sensing device.

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 2005년도 추계학술발표대회 논문집
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• pp.50-56
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• 2005

The robot systems are widely used in the many industrial field as well as welding manufacturing. The essential tasks to operate the welding robot are the acquisition of the position and/or shape of the parent metal. For the seam tracking or the robot tracking, many kinds of contact and non-contact sensors are used. Recently, the vision is most popular. In this paper, the development of the system which measures the shape of the welding part is described. This system uses the line-type structured laser diode and the vision sensor. It includes the correction of radial distortion which is often found in the image taken by the camera with short focal length. The Direct Linear Transformation (DLT) method is used for the camera calibration. The three dimensional shape of the parent metal is obtained after simple linear transformation. Some demos are shown to describe the performance of the developed system.

• 전자공학회논문지SC
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• 제45권6호
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• pp.149-156
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• 2008

SLAM(Simultaneous Localization and Mapping)은 무인 로봇 자동 항법시스템의 중요 기술로 센서 데이터로부터 로봇의 위치를 결정하고 기하학적 맵을 구성하는 것이다. 기존 방법으로는 초음파, 레이저 등의 거리 측정 센서를 이용해 로봇의 전역 위치를 찾는 방법과 스테레오 비전을 통한 방법이 개발되었다. 거리 측정 센서만으로 구성한 SLAM 시스템은 계산량이 간소하고 비용이 적게 들지만 센서의 오차나 비선형에 의해 정밀도가 조금 떨어진다. 이에 반해 스테레오 비전 시스템은 3차원 공간영역을 정확히 측정할 수 있지만 계산량이 많아 고사양의 시스템을 요구하고 스테레오 시스템 또한 고가이다. 따라서 본 논문에서는 단일 카메라 영상과 PSD(position sensitive device) 센서를 사용하여 SLAM을 구현하였다. 전방향의 PSD 센서로부터 일정 거리의 장애물을 감지하고 전면 카메라의 영상처리를 통해 장애물의 크기 및 특징을 감지한다. 위의 데이터를 통해 확률분포 SLAM을 구성하였고 실제 구현을 통해 성능검증을 하였다.

• 한국공작기계학회논문집
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• 제16권4호
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• pp.22-28
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• 2007

The welded defects are usually called user's unsatisfaction for appearance and functional usage. For checking these defects effectively without time loss, setup of weldability estimation system is an important for detecting whole specimen quality. In this study, after catching a rawdata on welded specimen profiles and treating vision processing with these data, the qualitative defects are estimated from getting these information by laser vision camera at first. At the same time, the weldability estimation for whole specimen is produced. For user friendly, the weldability estimation results are shown each profiles, final reports and visual graphics method. So, user can easily determined weldability. By applying these system to welding fabrication, these technologies are contribution to on-line setup of weldability estimation system.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.158-163
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• 2002

This paper presents a multiple sensor system for rapid and high-precision coordinate data acquisition in the OMM (On-machine measurement) process. In this research, three sensors (touch probe, laser, and vision sensor) are integrated to obtain more accurate measuring results. The touch-type probe has high accuracy, but is time-consuming. Vision sensor can acquire many point data rapidly over a spatial range but its accuracy is less than other sensors. Also, it is not possible to acquire data for invisible areas. Laser sensor has medium accuracy and measuring speed among the sensors, and can acquire data for sharp or rounded edge and the features with very small holes and/or grooves. However, it has range- constraints to use because of its system structure. In this research, a new optimum sensor integration method for OMM is proposed by integrating the multiple-sensor to accomplish mote effective inspection planning. To verify the effectiveness of the proposed method, simulation and experimental works are performed, and the results are analyzed.

• 한국공작기계학회논문집
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• 제16권1호
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• pp.60-68
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• 2007

It has been conducted by laser vision sensor for weldability estimation of front-bead after doing high speed butt laser welding of any condition. It has been developed a real time GUI(Graphic User Interface) system for weldability application in the basis of texts and field qualify levels. In the reference of bead imperfections, defects absolute position and defects intensity index of front-bead in the basis of formability reference, it has been produced a weldability estimation and defects intensity index of back-bead by back propagation neural network. In the result of by comparing measuring data by laser vision sensor of back-bead and data by back propagation neural network of one, it has been shown the similar results. Finally, under knowledge of welding condition in production line, it has been conducted a weldability estimation of back-bead only in knowledge of informations of front-bead data without using laser vision sensor or welding inspection experts and furthermore it can be used data for final inspection results of back-bead.

• 한국공작기계학회논문집
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• 제16권3호
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• pp.81-87
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• 2007

It is important to investigate the relationship between weld process parameters and weld bead geometry for adaptive arc robot welding. However, it is difficult to predict an exact back-bead owing to gap in process of butt welding. In this paper, the quantitative prediction system to specify the relationship external weld conditions and weld bead geometry was developed to get suitable back-bead in butt welding which is widely applied on industrial field. Multiple regression analysis and artificial neural network were used as the research methods. And, the results of two prediction methods were compared and analyzed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 학술대회 논문집 정보 및 제어부문
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• pp.89-90
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• 2008

본 논문은 네트워크를 통해서 이동로봇을 원격제어하기 위해 필요한 비전 시스템에서 HMD(Head Mounted Display)의 방향각 측정 알고리즘에 관한 연구이다. 우선 이 이동로봇 원격제어 시스템은 AP와 무선랜을 이용하여 독립 무선 네트워크를 구축하였고 이동로봇의 주변 환경을 레이저 센서와 스테레오 카메라를 이용하여 사용자에게 정보를 전송한다. 스테레오 카메라를 통해 전송된 영상 정보는 HMD를 통하여 볼 수 있다. 실시간으로 영상 카메라에 의해 측정 된 HMD의 회전 각도는 pen-tilt에 전송되어 HMD가 회전한 만큼 pen-tilt도 회전하여 이동로봇의 주변 환경 영상정보를 얻을 수 있는 알고리즘을 제안하였다.