양팔 로봇을 이용한 조립 작업에서 수명을 고려한 최적 운동 계획법

황면중,Hwang, Myun Joong 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.21 No.10

The objective of this research is to verify the quantitative efficiency of a bimanual robotic task. Bimanual robots can realize dexterous and complicated motions using two cooperating arms. However, its motion planning and control method are not simple for implementing flexible tasks such as assembly. In this paper, the proposed motion planning method is used to find an optimal solution satisfying a designed cost function and constraints with regard to the kinematics and redundancy of the bimanual robot. The simulation results show that the lifetime of the manipulator can be changed by the proposed cost function consisting of angular velocity and angular acceleration of each joint in the same assembly task.

레이저 적층 제조 기술 동향

황면중,조정호,Hwang, Myun Joong,Cho, Jungho 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.4

Additive manufacturing technology is taking great attentions in these days because the term 3D-printing became a hot issue as the next generation manufacturing paradigm. Especially, laser additive manufacturing is at the center of interest thanks to the accuracy compared to other heat sources. In this report, recent papers about laser additive manufacturing are analyzed and reviewed. General technology is specified into three different categories and they are laser sintering, laser melting and laser metal deposition. Similarities and differences are clearly described by detailed technologies and used materials type. Representative application examples are selected then future of this technology is expected through those applications. Additionally, market of laser additive manufacturing systems itself and application fields are also predicted based on present 3D-printing market and technical progressions.

회전 윤곽 상자를 이용한 표면 검사 알고리즘

황면중,정성엽,Hwang, Myun Joong,Chung, Seong Youb 한국교통대학교 융복합기술연구소 2016 융ㆍ복합기술연구소 논문집 Vol.6 No.1

DC motor shafts have several defects such as double cut, deep scratch on surface, and defects in diameter and length. The deep scratches are due to collision among the other shafts. So the scratches are long and thin but their orientations are random. If the smallest enclosing box, i.e. oriented bounding box for a detective point group is found, then the size of the corresponding defect can be modeled as its diagonal length. This paper proposes an suface inspection algorithm for the DC motor shaft using the oriented bounding box. To evaluate the proposed algorithm, a test bed is made with a line scan CCD camera (4096 pixels/line) and two rollers mechanism to rotate the shaft. The experimental result on a pre-processed image with contrast streching algorithm, shows that the proposed algorithm sucessfully finds 150 surface defects and its computation time (0.291 msec) is enough fast for the requirement (4 seconds).

로봇 핸드 제어를 위한 센서 기반 손 동작 인식

황면중(Hwang, Myun Joong) 한국산학기술학회 2014 한국산학기술학회논문지 Vol.15 No.9

사람의 생체 신호를 측정하여 로봇 제어에 이용하는 연구는 최근까지 활발히 진행되고 있다. 하지만 정확한 센서 정보를 위한 복잡한 신호 처리가 필요하고 고가의 시스템을 필요로 하는 단점이 있다. 본 논문에서는 저가의 EMG 센서와 Flex 센서로부터 측정된 신호를 이용하여 사람의 손 동작을 인식한 후 해당 움직임을 원격지의 로봇 핸드로 구현하는 것을 목표로 한다. MCU(Micro Controller Unit) 와 해당 센서들을 이용하여 실험적으로 사람의 손과 팔 부근의 3개의 센서 부착 위치를 결정하고 움직임에 따른 출력 신호와 실제 동작 사이의 구분 방법을 결정한다. 동작 인식 정확도를 높이기 위해 MCU 의 아날로그 기준 전압에 따른 디지털 값 변화 실험 수행 후 기준 전압을 3.3V로 선정하였다. 손 동작을 구현하기 위해 4개의 손가락과 손목부분으로 구성된 링크 구조의 로봇 핸드를 설계한 후 제작하였다. 결과적으로 간단한 센서와 저가의 MCU를 활용하여 원격지의 로봇 핸드를 제어할 수 있음을 보였다. Many studies have examined robot control using human bio signals but complicated signal processing and expensive hardware are necessary. This study proposes a method to recognize a human’s hand motion using a low-cost EMG sensor and Flex sensor. The method to classify movement of the hand and finger is determined from the change in output voltage measured through MCU. The analog reference voltage is determined to be 3.3V to increase the resolution of movement identification through experiment. The robotic hand is designed to realize the identified movement. The hand has four fingers and a wrist that are controlled using pneumatic cylinders and a DC servo motor, respectively. The results show that the proposed simple method can realize human hand motion in a remote environment using the fabricated robotic hand.

3차원 초음파 시스템의 캘리브레이션 방법

황면중(Hwang, Myun Joong) 한국산학기술학회 2013 한국산학기술학회논문지 Vol.14 No.12

본 논문에서는 의료용 초음파를 이용하는 로봇 시스템을 위한 3차원 캘리브레이션 방법을 제안한다. 고정된 기준점을 구성하기 위한 캘리브레이션 블록을 제작한 후 옵티컬 트래커(optical tracker) 를 이용하여 초음파 프루브 (probe) 의 위치와 기준점의 위치를 측정한다. 초음파 영상의 픽셀 좌표와 센서로 측정된 위치를 비교하여 6개의 파 라미터로 이루어진 초음파 프루브와 영상 내의 픽셀 좌표와의 관계 행렬을 구하고 2개의 파라미터로 이루어진 스케 일링 행렬을 계산한다. 정밀한 캘리브레이션을 위해 캘리브레이션 블록 내부 모양과 매질 선택에 대한 적절성을 실험 을 통해 검증한다. 제안된 방법은 간단한 형태의 캘리브레이션 블록과 옵티컬 트래커를 사용하여 설치에 많은 시간이 필요하지 않는 장점이 있기 때문에 초음파 영상을 이용하는 로봇 작업에 널리 적용이 가능하다. This paper proposes a calibration method for a freehand 3-D ultrasound system in medical robotic research. The calibration block with six wires was designed to set the fixed target points. The positions of the ultrasound probe and calibration block were measured using an optical tracker. The relationship between the position of the ultrasound probe and the pixel coordinates in the images was derived using a calibration process. The scaling matrix was also calculated. The experimental results showed that the proposed method could find solutions using a simple least square method from one or multiple ultrasound images.

모터 샤프트 이중컷 불량 검사 알고리즘

황면중(Myun Joong Hwang),정성엽(Seong Youb Chung) 한국산학기술학회 2017 한국산학기술학회논문지 Vol.18 No.2

본 논문은 모터 샤프트 제조 공정에서 발생하는 이중컷 불량을 검사하기 위한 영상 처리 알고리즘을 제안하였다. 알고리즘은 영상의 밝기를 이용하여 외곽선을 추출하는 단계와 추출된 외곽선을 이용하여 이진화된 경계선 그래프를 구하는 단계, 최종적으로 이진화된 경계선 그래프를 이용하여 불량품을 판정하는 단계로 구성된다. 본 논문에서는 두 절단면이 분리되어 있는 결함과 두 절단면이 연결되어 있는 결함을 각각 type 1 결함과 type 2 결함이라고 정의하였다. 실제 제조 과정에서 112개의 양품과 44개의 불량품 (type 1 불량 34개 및 type 2 불량 10개) 샘플을 수집하였으며, 수집한 샘플을 이용하여 제안된 알고리즘을 검증하였다. 알고리즘 시험 결과 100% 정확도로 양품과 불량품을 판정하였으며, 불량품의 경우도 type 1 불량과 type 2 불량을 정확히 구분하는 것으로 확인되었다. 본 논문에서 제안한 알고리즘은 추가적으로 다양한 샘플에 대해 신뢰성을 확보한 후 실제 현장에 사용할 계획이다. This paper proposes an image-processing algorithm for inspecting double-cut defects in the motor shaft manufacturing process. The algorithm consists of extracting the outline using the brightness of the image, obtaining a binarized boundary graph using the extracted outline, and determining the defects from the graph. Defects in which two cut surfaces are separated are considered type 1 defects, and those in which two cut surfaces are connected are defined as type 2 defects. In an actual manufacturing process, 112 good samples and 44 defective samples (34 type 1 defects and 10 type 2 defects) were collected and used to verify the algorithm. The samples were judged with 100% accuracy for both type 1 and type 2 defects. The algorithm will be used in the field after securing reliability for various samples.

양팔 로봇을 이용한 조립 작업에서 수명을 고려한 최적 운동 계획법

황면중(Myun Joong Hwang) 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.18 No.12

The objective of this research is to verify the quantitative efficiency of a bimanual robotic task. Bimanual robots can realize dexterous and complicated motions using two cooperating arms. However, its motion planning and control method are not simple for implementing flexible tasks such as assembly. In this paper, the proposed motion planning method is used to find an optimal solution satisfying a designed cost function and constraints with regard to the kinematics and redundancy of the bimanual robot. The simulation results show that the lifetime of the manipulator can be changed by the proposed cost function consisting of angular velocity and angular acceleration of each joint in the same assembly task.

작업 적합도를 이용한 양팔 로봇의 운동 계획

황면중(Myun Joong Hwang),정성엽(Seong Youb Chung),이두용(Doo Yong Lee) 제어로봇시스템학회 2008 제어·로봇·시스템학회 논문지 Vol.14 No.7

A cost-function based on manipulability and compatibility is designed to determine assembly motions of two cooperating manipulators. Assembly motions are planned along the direction maximizing performance indices to improve control performance of the two manipulators. This paper proposes bimanual task compatibility by defining cost functions. The proposed cost functions are applied and compared to the bimanual assembly task. The problem is formulated as a constrained optimization considering assembly constraints, position of the workpieces, and kinematics and redundancy of the bimanual robot. The proposed approach is evaluated with simulation of a peg-in-hole assembly with an L-shaped peg and two 3-dof manipulators.

양팔 로봇의 수명을 고려한 최적 운동 계획법

황면중(Myun Joong Hwang) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.4-2

직교좌표공간에서의 스플라인을 이용한 산업용 로봇의 궤적 생성 방법

정성엽,황면중,Chung, Seong Youb,Hwang, Myun Joong 한국교통대학교 융복합기술연구소 2016 융ㆍ복합기술연구소 논문집 Vol.6 No.2

Robot usually requires spline motion to move through multiple knots. In this paper, catmull-rom spline method is applied to the trajectory planning of industrial robot in task space. Centripetal catmull-rom is selected to avoid self-intersection and slow motion which can be occurred in uniform and chordal spline. The method to set two control points are proposed to satisfy velocity conditions of initial and final knots. To optimize robot motion, time scaling method is presented to minimize margin between real robot value and maximum value in velocity and acceleration. The simulation results show that the proposed methods are applied to trajectory planning and robot can follow the planned trajectory while robot motion does not exceed maximum value of velocity and acceleration.