정위치 해석해를 가지는 평면형 3자유도 병렬 메커니즘의 기구학 특성 분석 = Kinematic characteristic analysis of a planar 3-DOF parallel mechanism having closed-form position solution

국문 초록 (Abstract)

일반적인 3-RRR 평면형 3자유도 병렬 메커니즘은 정위치 해석해(closed form forward position solution)가 존재 하지 않는다. 그렇기 때문에, 정위치 해석해를 찾기 위해 수치 계산법(numerical method)을 사용함으로써 연산부담을 주게 된다. 그리고 특이형상(singularity configuration) 의 주변에서 저하된 동작을 보여주는 경향이 있다.
이 문제를 극복하기 위해, 다른 문헌에서 수정된 3-RRR 평면형 3자유도 병렬 메커니즘을 제안 하였다. 하지만 응용가능성 대한 충분한 이해와 자세한 분석은 이루어지지 않았다.
수정된 메커니즘은 일반적인 3-RRR 평면형 3자유도 병렬 메커니즘에서 운동판(moving plate)과 연결되는 두 개의 부속체인의 세 번째 회전관절을 동일한 축 방향으로 일치시키고 출력 좌표계의 위치를 그 동일한 축에 부착한 구조로 이루어진다. 분석이 수행된 구조와 기존의 3-RRR 평면형 3 자유도 병렬 메커니즘과의 기구학 특성 비교 분석을 통하여 본 메커니즘의 우수한 특성을 확인하였고 더 나아가 여유구동을 가질 때 두 메커니즘의 특이형상 분석으로부터 작업공간내에서 병렬 특이형상이 제거됨에 의해 기존의 3-RRR 평면형 3 자유도 병렬 메커니즘 보다 더 우수한 기구학 특성을 확인하였다.
작업공간 크기와 기구학 등방성 특성 관해서 수정된 메커니즘의 최적 기구학 설계를 수행 하였고 최적화 결과를 기초로 시제품을 구현하였으며 메커니즘의 구동 확인을 위한 예비 모션 능력 시험을 수행 하였다.
수정된 병렬 로봇의 구현과 기존 3-RRR 평면형 3자유도 병렬 메커니즘 사이에 비교한 기구학 분석으로부터 높은 응용 가능성을 갖는 것을 충족 한 것을 확인하였다.

다국어 초록 (Multilingual Abstract)

The typical 3-RRR type planar 3-DOF parallel mechanism (PM) does not have a closed form forward position solution. Thus, to find the forward position solution, a numerical method requiring the heavy computational load should be employed. Thus, the mechanism tends to show the deteriorated performance in the neighborhood of its singularity configuration. To overcome such problems, a modified 3-RRR type planar 3-DOF PM has been suggested in literature. However, the in-depth analysis on the modified mechanism has not been conducted to fully understand its application potentials.
The modified mechanism is formed by placing the third joint active joints of two subchains connected the moving plate of the typical 3-RRR type planar 3-DOF PM at the same position. Through the comparative study on kinematic characteristic of those two PMs, the modified PM and the typical 3-DOF PM, it is confirmed that the modified mechanism has good kinematic characteristic as the typical 3-DOF PM. Further, from the singularity analysis for those two mechanisms when they are redundantly actuated, it is confirmed that the modified PM shows the better kinematic characteristics than the typical 3-DOF PM, by removing the most of parallel singularities within its workspace. Optimal kinematic design of the modified PM is conducted with respect to the workspace size and kinematic isotropy characteristics, and the prototype is implemented based on the optimization result. Then the preliminary motion capability test is conducted to verify its performance.
From the comparative kinematic analyses between the modified PM and the typical 3-RRR type planar 3-DOF PM, and through the implementation of the modified PM, it can be contented that the modified mechanism has a very high application potential and particularly the future investigation for its advantageous features such as redundant actuations should be made.

목차 (Table of Contents)

• 목 차
• Abstract••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• i
• 요 약•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• iii
• 목 차•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• v
• 그림목차•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• vi
• 표 목 차••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• viii
• 1. 서론•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 1
• 2. 수정된 구조의 평면형 3-자유도 메커니즘의 구성•••••••••••••••••••••••• 3
• 3. 기구학 해석•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 5
• 3.1 역 위치 해석••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 5
• 3.2 정 위치 해석••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 11
• 3.3 스크류 이론을 이용한 일차 기구학 해석••••••••••••••••••••••••••• 19
• 3.4 특이형상 해석••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 29
• 3.5 여유구동에 따른 일차 기구학 해석••••••••••••••••••••••••••••••••••• 34
• 3.6 여유구동에 따른 특이형상 해석••••••••••••••••••••••••••••••••••••••• 38
• 4. 기구설계•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 42
• 4.1 기구학적 설계 지수••••••••••••••••••••••••••••••••••••••••••••••••••••••• 42
• 4.2 최적설계•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 44
• 4.3 시뮬레이션 : 3-RRR 평면형 3자유도 병렬 메커니즘과의
• 기구학 특성 비교•••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 50
• 4.4 시물레이션: 여유구동 기구학 특성 비교 •••••••••••••••••••••••••• 57
• 5. 메커니즘의 구현•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 61
• 6. 결론 및 향후 과제••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 69
• 참 고 문 헌••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 70