Dynamic Evaluation Method of Roundness Uncertainty Based on Bayesian Principle

Abstract

The invention provides a dynamic evaluation method of roundness uncertainty based on Bayesian principle, which includes: sampling the roundness of the measured object to obtain a set of measurement point data; fitting a circle according to the measurement point data, and then calculating Out of roundness error; collect multiple sets of measurement point data, and calculate the roundness error for each set of measurement point data, and use multiple roundness errors as a set of random variables; establish the probability density function of random variables, and construct the probability density Constraint conditions; take the sample origin moment as the condition, and the probability density constraint as the objective function, estimate the probability density function of the group of random variables and use it as a priori distribution; obtain another group of random variables, and then calculate and generate another probability density Function, the probability density function of another set of random variables is fused into the prior distribution to form the posterior distribution. The invention can realize the fusion of geometric tolerance measurement information, and further realize the dynamic evaluation of uncertainty.

Description

technical field [0001] The invention relates to precision measurement and computer application, in particular to a dynamic evaluation method of roundness uncertainty based on Bayesian principle. Background technique [0002] With the rapid development of industrial process informatization and intelligence, new manufacturing models such as Industry 4.0 and intelligent manufacturing have been widely discussed and studied. Under the new industrial manufacturing system, product measurement technology requirements that meet the characteristics of cyber-physical systems are necessary. According to modern error theory, when measuring the size of a workpiece, not only the size measurement result must be obtained, but also the uncertainty of the result must be included. In the new generation of product geometric specification (GPS), the measurement uncertainty is called execution uncertainty. degree into the system. [0003] The core of the Bayesian model is to realize the fusion o...

AI Technical Summary

Problems solved by technology

The existing research mainly includes the following contents: Bayesian method is adopted for the evaluation of measurement uncertainty of small samples in calibration and inspection, and each calibration or inspection data is effectively used, but the description of prior and posterior distributions is mainly based on Traditional statistical methods or empirical assumptions; a Bayesian measurement uncertainty evaluation method based on the maximum entropy theory is proposed, which realizes the maximum entropy expression form of the posterior distribution PDF, but its prior distribution is mainly based on empirical assumptions; using Based on the principle of Bayesian information fusion and statistical inference, a dynamic evaluation model of uncertainty has been established and verified by digital simulation experiments. Reflect the characteristics and advantages of Bayesian information fusion

In addition, the above studies are mainly aimed at the uncertainty evaluation of a single variable, and there are no relevant reports in the field of multivariate geometric tolerance measurement uncertainty

[0004] In view of the above problems, the research on measurement information fusion and dynamic evaluation methods for roundness error uncertainty is very limited, especially the field of information fusion does not involve the category of geometric tolerance

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