Free Surface Non-contact Measurement Methods Research And System Development

With the development of modern CAD/CAM and NC technology, the advanced measurement technique is urgently to be developed by industrial users. In this dissertation, based on the survey of the present research situation and development trends at home and abroad of the numerical control measurement methods, measurement layout, surface modeling, the integration technology of measuring, modeling and manufacturing of freeform surface parts, with the comprehensive knowledge of computer vision, precision mechanism, photoelectron, CAD/CAM and automatic control, a non-contact laser measurement system is developed on the GT control card. Meanwhile the relevant problems on the measurement methods and technology of profile manufacturing are profoundly studied. The main work in the dissertation is arranged as follows:1. The rectangle-division method for unknown-surface adaptive measurement is firstly provided to realize adaptive distribution of measurement points. The validity of this method is testified through simulation analysis and a mouse model experiment. The methodology provides a new way for improving measurement precision and efficiency.2. The disadvantage of laser probe's small linear measurement range is analyzed. Three tracing measurement are introduced, and the profile tracing measurement is emphasized. Then a model of automatically choosing tracing measurement is provided.3. Boundary information extracted from CCD images is used to direct measurement layout. Measurement principle and method of CCD are introduced. The CCD calibration method is also provided. The measurement layout is testified to be optimized by a simulation analyse of mouse model measurement under the help of CCD.4. The laser measurement system based on GT card is developed. The precision servo and mechanism are narrated, and the software structure is introduced. Several measurement examples show that the system can rapidly collect 3-D information, which provides the theory and experience for building 3M system.5. Numerical profile manufacturing principle is introduced. The project of "Laser Measurement Profile Milling Machine Based on Hangtian NC" is completed by cooperating with Beijing Hangtian NC Co. Ltd. and Hangzhou Machine Works. The feasibility of the system is testified through a mouse model measurement and manufacturing. The work is helpful for the realization of developing profile manufacturing control system.Finally, main results and conclusions of this dissertation have been summarized; the prospects and study emphases of the future research work have been discussed and forecast.