서지주요정보
삼각형 다면체 근사법을 이용한 미지자유곡면의 자율적 디지타이징 = Autonomous digitization of unknown free-form surfaces by triangular polyhedral approximation
서명 / 저자 삼각형 다면체 근사법을 이용한 미지자유곡면의 자율적 디지타이징 = Autonomous digitization of unknown free-form surfaces by triangular polyhedral approximation / 송창규.
저자명 송창규 ; Song, Chang-Kyu
발행사항 [대전 : 한국과학기술원, 1996].
Online Access 원문보기 원문인쇄

소장정보

등록번호

8006198

소장위치/청구기호

학술문화관(문화관) 보존서고

DME 96025

휴대폰 전송

도서상태

이용가능

대출가능

반납예정일

초록정보

For automatic machining of a free-form surface, an effective tool of surface-modeling is needed to generate the numeric data of the desired surface. Computer-aided modeling technique is nowadays widely available, but this software modeling often turns out to be unproductive when the surface is of a complex shape designed from aesthetic viewpoints. In this case, reverse engineering technique can be usefully incorporated in that an 1:1 or reduced model of the desired surface is prefabricated with clay or wood and then a digitization process is performed against the model. A CNC coordinate measuring machine equipped with a conventional contact probe may be efficiently used for digitization of reverse engineering. A simple way of performing digitization is to sample height data at fixed xy-coordinates which may be predertermined either merely by equispaced grid points or by some statistical approaches. However, this passive sampling tends to result in a collection of data that is too dense with abundant points of no significance or too sparse to satisfy a specified geometric tolerence of approximation. This problem can be improved if sample points are selected adaptively during digitization by estimating the actual surface profile continuously from the data being sampled. In this thesis, we present an operational algorithm of digitization which can supervise the movement of s contact probe in an autonomous manner. The surface is discretely sampled and fitted by using a polyhedral surface model of triangular patches. The vertex points of the polyhedron are adaptively annexed as digitization proceeds to represent the surface with a minimum number of data satisfying a specified geometric tolerence. The database structure which represent the polyhedron is LTL structure. An improved algorithm of the triangulation, which reforms the triangular patch to equi-lateral triangle, is included to prevent deformity of triangular patch. A real-time path planning of the probe is also provided to reduce total measuring time. Three sample objects are measured for algorithm efficiency test. As the result of actually measuring, proposed autonomous digitization saved the measuring time and measuring points. The point data which is gained from digitization is not correspond with the measuring surface because probe ball has finite radius. So compensation algorithm of the probe radius is needed and three algorithms are provided to find out the actual contact point. In three compensation algorithms, the contact point is calculated by presuming tangent plane and coordinate rotating method is showed best results through several simulations.

서지기타정보

서지기타정보
청구기호 {DME 96025
형태사항 xiii, 135 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Chang-Kyu Song
지도교수의 한글표기 : 김승우
지도교수의 영문표기 : Seung-Woo Kim
학위논문 학위논문(박사) - 한국과학기술원 : 기계공학과,
서지주기 참고문헌 : p. 128-135
주제 삼차원측정기
접촉식프로브
자율적 디지타이징
프로브경로계획법
프로브반경보정
CMM
Probe path planning
Autonomous digitization
Probe radius compensation
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