수치적인 역운동학 기반 UKF를 이용한 효율적인 중간 관절 추정

서융호(Yungho Seo),이준성(Junsung Lee),이칠우(Chilwoo Lee) 大韓電子工學會 2010 電子工學會論文誌-SP (Signal processing) Vol.47 No.6

영상 기반의 모션 캡처에 대한 연구는 인체의 특징 영역 검출, 정확한 자세 추정 및 실시간 성능 등의 문제를 풀기 위해 많은 연구가 진행되고 있다. 특히, 인체의 많은 관절 정보를 복원하기 위해 다양한 방법이 제안되고 있다. 본 논문에서는 수치적인 역운동학 방법의 단점을 개선한 실시간 모션 캡처 방법을 제안한다. 기존의 수치적인 역운동학 방법은 많은 반복 연산이 필요하며, 국부최소치 문제가 발생할 수 있다. 본 논문에서는 이러한 문제를 해결하기 위해 기존의 수치적인 역운동학 해법과 UKF를 결합하여 중간관절을 복원하는 방법을 제안한다. 수치적인 역운동학의 해와 UKF를 결합함으로써, 중간 관절 추정 시 최적값에 보다 안정적이고 빠른 수렴이 가능하다. 모션 캡처를 위해 먼저, 배경 차분과 피부색 검출 방법을 이용하여 인체의 특징 영역을 추출한다. 다수의 카메라로부터 추출된 2차원 인체 영역 정보로부터 3차원 정보를 복원하고, UKF와 결합된 수치적인 역운동학 해법을 통해 동작자의 중간 관절 정보를 추정한다. 수치적인 역운동학의 해는 UKF의 상태 추정 시 안정적인 방향을 제시하고, UKF는 다수의 샘플을 기반으로 최적 상태를 찾음으로써, 전역해에 보다 빠르게 수렴한다. A research of image-based articulated pose estimation has some problems such as detection of human feature, precise pose estimation, and real-time performance. In particular, various methods are currently presented for recovering many joints of human body. We propose the novel numerical inverse kinematics improved with the UKF(unscented Kalman filter) in order to estimate the human pose in real-time. An existing numerical inverse kinematics is required many iterations for solving the optimal estimation and has some problems such as the singularity of jacobian matrix and a local minima. To solve these problems, we combine the UKF as a tool for optimal state estimation with the numerical inverse kinematics. Combining the solution of the numerical inverse kinematics with the sampling based UKF provides the stability and rapid convergence to optimal estimate. In order to estimate the human pose, we extract the interesting human body using both background subtraction and skin color detection algorithm. We localize its 3D position with the camera geometry. Next, through we use the UKF based numerical inverse kinematics, we generate the intermediate joints that are not detect from the images. Proposed method complements the defect of numerical inverse kinematics such as a computational complexity and an accuracy of estimation.

세 개의 회전축을 가진 5축 밀링 가공의 NC 데이터 후처리 방법

윤재득(Jae-Deuk Yun),정융호(Yoong-Ho Jung),김태경(Tae-Gyeong Kim) 한국생산제조학회 2009 한국공작기계학회 추계학술대회논문집 Vol.2009 No.-

We present a postprocessing algorithm for 5-axis machines, which can be applied to 2 rotary axes (2R-3L) types and 3 rotary axes (3R-2L) types. Five-axis machining requires a postprocessor for converting cutter-location (CL) data to machine-control (NC) data. The existing methods for postprocessing use inverse kinematics equations from the forward kinematics. However, for 5-axis machines with three rotary axes, the inverse kinematics equations cannot be induced directly, because the forward kinematics equations are nonlinear. To derive the joint values from the forward kinematics equations, previous algorithms use numerical methods for the postprocessing; this requires a search algorithm with much computation time and may fail to obtain a solution. We propose a general method for the postprocessing that can be applied to both 2-rotary and 3-rotary 5-axis machines. Our algorithm has three advantages: first, the forward kinematics equations are not required; second, the method is reliable and eliminates the need for numerical methods for the inverse kinematics, which results in exact solution; and finally, the proposed algorithm can also be applied to 2R-3L 5-axis machines.

세 개의 회전축을 가진 5축 밀링 가공의 NC 데이터 후처리 방법

윤재득(Jae-Deuk Yun),정융호(Yoong-Ho Jung),김태경(Tae-Gyeong Kim) 한국생산제조학회 2009 한국생산제조시스템학회 학술발표대회 논문집 Vol.2009 No.10

We present a postprocessing algorithm for 5-axis machines, which can be applied to 2 rotary axes (2R-3L) types and 3 rotary axes (3R-2L) types. Five-axis machining requires a postprocessor for converting cutter-location (CL) data to machine-control (NC) data. The existing methods for postprocessing use inverse kinematics equations from the forward kinematics. However, for 5-axis machines with three rotary axes, the inverse kinematics equations cannot be induced directly, because the forward kinematics equations are nonlinear. To derive the joint values from the forward kinematics equations, previous algorithms use numerical methods for the postprocessing; this requires a search algorithm with much computation time and may fail to obtain a solution. We propose a general method for the postprocessing that can be applied to both 2-rotary and 3-rotary 5-axis machines. Our algorithm has three advantages: first, the forward kinematics equations are not required; second, the method is reliable and eliminates the need for numerical methods for the inverse kinematics, which results in exact solution; and finally, the proposed algorithm can also be applied to 2R-3L 5-axis machines.

기하학적인 방법을 이용한 3 Rotary 형식 5축 가공기의 후처리 방법

윤재득(Jaedeuk Yun),정융호(Yoongho Jung),박도현(Dohyun Park) (사)한국CDE학회 2009 한국CDE학회 논문집 Vol.14 No.5

This paper presents a post-processing algorithm for 5-axis machines with three rotary axes (3R-2L type). 5-axis machining needs the postprocessor for converting cutter location (CL) data to machine control (NC) data. The existing methods for post-processing use inverse kinematics equations from forward kinematics. However in case of 5-axis machines with three rotary axes, the inverse kinematics equations are not induced directly since the forward kinematics equations are non-linear. In order to get the joint values from the forward kinematics equations, previous algorithms use numerical method for the post-processing, which needs searching algorithms with computation time and may result in fail. This paper proposes a geometric method for the post-processing of 3 rotary type 5-axis machines. Our algorithm has three advantages: first, it does not need establishing forward kinematics equations. Second, it is reliable method that eliminates any numerical methods for the inverse kinematics, resulting in the exact solution. Finally, the proposed algorithm can also be applied to 2R-3L type of 5-axis machines.

기구학적 분석을 이용한 로봇 매니퓰레이터 개발

민병로(Min Byeong-Ro),이대원(Lee Dae-Weon) (사)한국생물환경조절학회 2004 생물환경조절학회지 Vol.13 No.1

본 연구는 오이수확기의 매니퓰레이터 개발을 위한 기구학적 분석을 하는 것이다. 매니퓰레이터의 정방향 기구학 및 역방향 기구학 분석을 한 후 실제 장치의 반복오차 측정실험을 통해 이론 값을 검증하였다. 매니 퓰레이터는 총 세 개의 링크로서 한 개의 수직링크와 두개의 회전링크로 구성되어져 있으며, 세 개의 스테핑 모터가 각 관절에 장착되어 링크에 동력을 전달한다. 주요 연구결과를 요약하면 다음과 같다. D-H Parameter를 이용하여 정방향 기구학에 의한 매니퓰레이터의 변환 연산자를 얻었다. 역방향 기구학의 해는 두가지로 나타났으며 삼각함수를 이용하여 해를 구하였다. 매니퓰레이터의 반복오차를 측정한 검증 실험에서는 X, Y, Z축에 대하여 반복 오차가 최대 2.60 ㎜, 2.05 ㎜, 1.55 ㎜로 나타났으며, 정방향 및 역방향 기구학에서 오차의 최대지점 및 최소지점의 실제 좌표는 일치하였다. 반복오차 측정 결과는 매니퓰레이터의 목표지점인 오이의 직경에 비해 비교적 작게 나타났다. 측정오치는 실험중 발생한 실험오차로 판단된다. 매니퓰레이터의 오차를 줄이고 작업능률의 향상을 위해서는 링크의 수를 줄이고 오이의 품종 및 재배환경을 고려하여야 하며, 경량이면서도 견고한 재료를 사용하여 하중을 줄여야 한다. This study is kinematics for the manipulator development of cucumber harvesting. A theory value was verified by repeated error measurement after the forward kinematics or inverse kinematics analysis of manipulator. Manipulator is consisted of one perpendicular link and two revolution link. The transformation of manipulator can be valued by kinematics using Denavit-Hartenberg parameter. The value of inverse kinematics which is solved by three angles faction shows two types. Repeated errors refered maximum 2.60 ㎜, 2.05 ㎜ and 1.55 ㎜ according to X, Y, Z axis. In this study, the actual coordinates of maximum point and minimum point were agreement in the forward kinematics or inverse kinematics. The results of repeated error measurement were reflect to be smaller compared to a diameter of cucumber. measurement errors were determined by experimented errors during the test. For reducing errors of manipulator and improving work efficiency, the number of link should be reduced and breeding and cultural environment should be considered to reduce the weight and use the hard stuff. The velocity of motor for working should be considered, too.

A Geometric Postprocessing Method for 5-axis Machine Tools using Locations of Joint Points

Yun, Jaedeuk,Jung, Yoongho,Kurfess, Thomas 한국정밀공학회 2013 International Journal of Precision Engineering and Vol.14 No.11

We present a postprocessing algorithm for 5-axis machines, which can be applied to types with two rotary axes (2R-3L) and three rotary axes (3R-2L). Five-axis machining requires a postprocessor for converting cutter-location (CL) data to numerical-control (NC) data. The existing methods for postprocessing use inverse kinematics equations from the forward kinematics. However, for 5-axis machines with three rotary axes, the inverse kinematics equations cannot be induced directly, because the forward kinematics equations are coupled. To derive the joint values from the forward kinematics equations, previous algorithms use iterative numerical methods for the postprocessing; this requires a search algorithm with much computation time and may fail to obtain a solution. Our algorithm has three advantages: first, the forward kinematics equations are not required; second, the method is reliable and eliminates the need for numerical methods for the inverse kinematics, which results in exact solutions; and finally, the proposed algorithm is generic for 5-axis machines, which can also be applied to 2R-3L 5-axis machines.

Geometric Postprocessing Method for 5-axis Machine Tools using Locations of Joint Points

윤재득,정융호,Thomas Kurfess 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

We present a postprocessing algorithm for 5-axis machines, which can be applied to types with two rotary axes (2R-3L) and three rotary axes (3R-2L). Five-axis machining requires a postprocessor for converting cutter-location (CL) data to numerical-control (NC)data. The existing methods for postprocessing use inverse kinematics equations from the forward kinematics. However, for 5-axis machines with three rotary axes, the inverse kinematics equations cannot be induced directly, because the forward kinematics equations are coupled. To derive the joint values from the forward kinematics equations, previous algorithms use iterative numerical methods for the postprocessing; this requires a search algorithm with much computation time and may fail to obtain a solution. Our algorithm has three advantages: first, the forward kinematics equations are not required; second, the method is reliable and eliminates the need for numerical methods for the inverse kinematics, which results in exact solutions; and finally, the proposed algorithm is generic for 5-axis machines, which can also be applied to 2R-3L 5-axis machines.

7자유도 인간형 로봇 팔의 직관적인 팔꿈치 위치 설정이 가능한 역기구학 알고리즘

김영렬,송재복 한국로봇학회 2011 로봇학회 논문지 Vol.6 No.1

Control and trajectory generation of a 7 DOF anthropomorphic robot arm suffer from computational complexity and singularity problem because of numerical inverse kinematics. To deal with such problems, analytical methods for a redundant robot arm have been researched to enhance the performance of inverse kinematics. In this research, we propose an analytical inverse kinematics algorithm for a 7 DOF anthropomorphic robot arm. Using this algorithm, it is possible to generate a trajectory passing through the singular points and intuitively move the elbow without regard to the end-effector pose. Performance of the proposed algorithm was verified by various simulations. It is shown that the trajectory planning using this algorithm provides correct results near the singular points and can utilize redundancy intuitively.

만능 4축 병렬 스테이지의 설계

김성환(S.H. Kim),박진수(J.S. Park),박호철(H.C. Park),김동진(D.J. Kim),박명철(M.C. Park) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11

The precise alignment of two glasses is a typical procedure in LCD or OLED assembly. For this process, the vision system evaluates position errors between glasses by detecting the pattern markers printed in each glass and the X, Y, R stage moves one glass to another in order to correct the error. Commonly used 2-D moving stage, called the 4-Axes Parallel Stage, has 3 motors at each corner which respectively move in X1, X2, Y or X, Y1, Y2 direction. In this stage, 3 axes motions combine to make the X, Y, R motion. Therefore the required 3 axes feed need to be calculated from the X, Y, R errors using inverse kinematics. But the inverse kinematics conversion has too many possible cases because of the diversity in stage configuration such as the motors positions and directions. In this work, the multi purpose stage is designed to transform into any configuration that can occur in practical application. When the new configuration stage is designed, inverse kinematics conversion is derived and verified in desktop environment using multi purpose parallel stage. Through this work, stage control system can be developed more efficiently.

마이크로 부품 조립을 위한 평면 3-PRP 정렬기의 역기구학

이정재(Jeong-Jae Lee),유용환(Young-Hwan Yoo),이창우(Chang-Woo Lee),송준엽(Jun Yeob Song),이수훈(Soo-Hun Lee),홍민성(Min-Sung Hong),이문구(Moon G. Lee) 한국생산제조학회 2010 한국공작기계학회 추계학술대회논문집 Vol.2010 No.-

In the field of micro-factory, there are demanded on aligning micro-components when they assemble an automatic focusing actuator of camera module for cellular phone and mount a dental crown on artificial root. This paper presents inverse kinematics of three degree-of-freedom (DOF) planar parallel actuated manipulators for the alignment. The 3-PRP (Prismatic-Revolute-Prismatic) manipulator is actuated by the voice coil motors (VCMs). The actuators are arrayed 120° apart symmetrically on the horizontal plate. Numerical simulation of the kinematical motion of 3-PRP manipulator is performed by using inverse kinematics. Furthermore, based on these results, the working range of the manipulator is estimated before experiments. Also, this paper presents control algorithm to drive the manipulator. The control algorithm is using a feedback control based on the inverse kinematics, sensor kinematics and governing equation of VCM. The algorithm controls each VCM independently.