Study On The Estimation Of Uncertainty In Improved GPS Standards System

By the developing of the information technology, the designing and controlling method of geometric precision can not meet the requirement of the developing of the technology of advanced designing and manufacturing. So the International Organization for Standardization (ISO) proposed the improved GPS (geometrical product specification) standard system. Improved geometrical product specification (GPS) is an internationally accepted standards system. It is the foundation of the technology standards and metrology specifications of mechanical and electric product. In the improved GPS standard system, uncertainty is used as an economic tool to enable an optimum allocation of resources amongst specification, manufacturing and verification. So uncertainty becomes one of the basic theories and key technologies in the improved GPS. This research includes the research on the uncertainty estimation as following:Firstly, the uncertainty theory in the improved GPS standard system is studied, including: the concept system of uncertainty, the influence of uncertainty to the basic principle of the improved GPS standard system, the application foreground of uncertainty in future manufacturing and the decision rules of uncertainty in the verification of product.Secondly, the calculation method for the uncertainty of the form error verification in the coordinate measurement is proposed in this paper. The calculation equation of compliance uncertainty in three-dimensional form error measuring process is deduced based on the basic principle of least-square verification and the transparent box model given in ISO/TS 14253-2. As a case study, a plate is measured and verified to validate the proposed method. By adopting the professional software Table Curve 3D and Matlab, the form error can be verified effectively.At last, the Monte Carlo simulation method of uncertainty estimation is presented based on Matlab. A prototype system of Monte Carlo simulation is established to estimate the measurement uncertainty in the experiment"measuring the inside cone angle with high degree off accuracy by using two balls". The Procedure for Uncertainty Management method (PUMA) is used to improve the measuring process and make a better measuring plan to satisfy the requirement of the target uncertainty.This thesis is financially supported by Foundation of education office of Guangxi Province of China, named"Mechanics and Allocation Method of Uncertainty in the Improved GPS Standard System"(Grant No. D200526) and Guangxi Science Foundation of China, named"Research on the Calculation model and method of the Improved GPS Standard System". (Grant No. 0640166).