Evaluation Of Measurement Uncertainty In Result Of Form And Position Error

The errors of form and position are parameters for the evaluation of mechanical components. It has great influence on the performance of products and the quality of assembly, which should be measurement and controlled. Measurement uncertainty should be contained in a scientific measurement result. However, today's uncertainty evaluation methods to the results of position and form errors have not been deeply and systematically studied. Thus, a systematic research on that topic is of great significance.More systematic research of the evaluation of measurement uncertainty in form and position errors was proposed in this paper. The research status of home and abroad on this subject were surveyed and analyzed. And the measurement methods and the evaluation methods of form and position errors were systematically studied. In this paper, based on least square principle a mathematic model was established from measurement results of coordinate measuring method. According to the mentioned results, the uncertainties of form and position errors were assessed.The main results of work and achievement are as follows:(1) The measurement methods of form error were summarized and classified. And the sources of measurement uncertainty were analysised.(2) Based on the least-squares principle, the mathematical models of form and position errors were established in the Cartesian coordinate. To the form and position errors for the rotational, such as roundness error and cylindrical error, the mathematical models of form and position errors were also established in the polar coordinates.(3) The uncertainty evaluation was based on Guide to the Expression of Uncertainty in Measurement (GUM). The uncertainty of the parameters of form and position errors, transmission coefficients and parameters of the correlation were Calculated. Then the standard uncertainty of form and position errors was evaluated based on GUM.(4) A probability distribution was established from the random numbers generated based on the principle of Monte Carlo Method in order to simulate the measured values and the uncertainties were evaluated later. (5) The theoretical results were verified by Experiments. Measuring the form and position errors and then using MATLAB programming to process the measurement results by different methods of measurement uncertainty. And the performance of different methods was comparedThe results and achievements in this paper have important scientific significance for the metrology and measuring error theory, and would have practical worth for the measurement and control to the form and position error of machinery manufacturing.