Automatic Profile Measurement And Evaluation Study In Micro-parts Based On Entire Imaging Measuring Method

Nowadays high precision and intelligent are important development directions in the field of measurement instruments. They put forward higher requirements for the means, efficiency and precision of the detection. The part profile error is an item which has been applied widely in the national and international standard, but it is difficult to measure and evaluate. Because of the low precision and efficiency, the available measurement and evaluation can't meet the high precision, which is required by the on-line parts' profile measurement in the field of micro-parts detection.According to the present situation of micro-parts detection, this paper proposed the method of profile measurement and evaluation based on the entire image measuring method. Several key issues of profile measurement and evaluation method are studied on and solved, including digital profile modeling on theory for the parts to be measured, the pre-oriented adjustment for the measured profile, the confirmation of the deviation value and deviation direction for the measured profile, as well as the construction of the error evaluation model for the profile in accordance with the definition of profile error. In order to explore a new road for the high precision and automatic measurement of the micro-parts, the software design of the measuring system and various functions module are realized. The main work is as follows:1. Zero-error modeling method for the profile modeling on theory was proposed based on the DXF File; one of innovative points in this article is the simple design ruler of digital template file. The technology of picking and storing for the entity elements of DXF File and the searching and scanning for the theoretical outline circuits were realized .The digital template of Zero-Error parts to be measured was founded.2. The method of adjusting the pose of measured profile with theoretical profile , according to different kinds of parts , integrated feature points or ellipse of inertia for realizing pre-position should be used .3. The method of using bound searching method of expansion polar angle and the distance between curve and point to determine deviation value for the profile quickly, meanwhile, the method to confirm deviation direction of measured point is given, which is another innovative point in this article. 4. Construct the model of evaluation method of the least-deviation method for profile errors, to make consistent with the definition of profile error. The evaluation of line profile error which satisfies the minimum condition with the method of successive approximation is realized.5. The software design of the measuring system and the realization of various functions model are accomplished, also, the measurement results are given by the way of figure style. The efficiency and precision of measurement system are verified experimentally, so it can satisfy the fast profile error measuring of the micro-parts.