http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Chi-Fai Cheung (검색결과 2 건)
- 무료
- 기관 내 무료
- 유료
-
Stiffness Modeling and Optimization of a 3-DOF Parallel Robot in a Serial-Parallel Polishing Machine
Peng Xu,Bing Li,Chi-Fai Cheung,Ju-Fan Zhang 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.4
Polishing is a kind of finishing process that can effectively reduce the surface defects and improve the form accuracy. This paper presents a novel hybrid machine with 6 degrees of freedom (DOF) serial-parallel topological structure used as an ultra-precision polishing equipment which is composed of a 3-DOF parallel robot, a 2-DOF serial robot and a turntable providing a redundant DOF. Due to the complexity of structure, stiffness performance evaluation of the parallel robot becomes a challenge. As a result, a theoretical model of the parallel robot based on the virtual work principle and the deformation superposition principle is formulated for analyzing the stiffness performance. With the developed model, a multi-objective dimensional optimization method is developed to maximize both the workspace volume and the global stiffness performance of the parallel robot. Artificial intelligence approach based on genetic algorithms is implemented to obtain an optimal combination of structural parameters. The effectiveness of this method is validated by simulation and the parallel robot with optimized structural parameters has a workspace with higher stiffness performance, hence justifies its suitability for high precision polishing.
-
Novel Auto-regressive Measurement of Diamond Tool Wear in Ultra-precision Raster Milling
Shao-Jian Zhang,Suet To,Chi-Fai Cheung,Jian-Jun Du 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.
In this paper, a new auto-regressive algorithm is proposed to reconstruct 3D topographic surface for diamond tool wear, using its in-process image. First, based on digital image processing technique, tool wear lands are separated from a tool wear image captured by a CCD camera under a 100X optical system; Second, a traverse search method of arc translation is put forward to eliminate feigned wear lands, and a least square polynomial method is adopted to fit inner- and outer-contours of the wear lands, self-adaptively filtering noises and connecting the discontinuous wear lands; Finally, the auto-regressive calibration method is developed to reconstruct its 3D topographic surface. The wear land is extracted self-adaptively, and the wear area, maximal wear width, average wear width and worn volume can be determined automatically by the algorithm. The reconstructed 3D topography of the tool wear land can be identified, based on the tool wear image captured by SEM. The result indicates that the method is capable of reconstructing 3D topography of the tool wear land and provides a possibility for in-process 3D-wear measurement in ultra-precision raster milling (UPRM) and the algorithm reliability is validated finally. And the influence of tool wear on surface roughness is discussed.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
