Form Tolerance Modeling And Error Evaluation Techniques Based On GPS

Tolerance design and error evaluation influence the product designing and manufacturing processes, they are of great importance in the development of modern manufacture.Having analysed recent research status of tolerance modeling theories, error evaluation techniques and the Geometrical Product Specification (GPS), it is studied that the methods of tolerance modeling and error evaluation.Meanwhile, combining with the National Natural Science Foundation of China ("Research on Tolerance Modeling Based on Geometrical Product Specification", No. 50505046), the form tolerance models based on the SDT theory and the error evaluation models are established in this dissertation, and a software system is also developed.In Chapter 1, recent researches on tolerance modeling theories, error evaluation techniques and the Geometrical Product Specification are summarized.The main contents and the general structure scheme of the dissertation are also given.In Chapter 2, the basic theories of tolerance modeling and error evaluation based on GPS are discussed.The concepts of surface model, feature, constraint, operator and invariance class are introduced.Then methods of tolerance math modeling are interpreted and applied to the seven basic invariance classes. At last, the definition and classification of uncertainty are presented, the relationship between measurement uncertainty and error evaluation result is also discussed.In Chapter 3, the definition of form tolerance and the tolerance principles are explained.According to the SDT theory, a new method of three-dimensional tolerance modeling is proposed.Then the models of straightnesse, flatness, roundness and cylindricity are built using this modeling method.In Chapter 4, by analysing the principles of differents form error evaluation methods, the evaluation functions are given.Then the constriction factor model of Particle Swarm Optimization (PSO) is researched and applied to calculate the optimization values. At last, an example is provided to validate the method.In Chapter 5, a form tolerance error evaluation system is developed and integrated into Solid Works 2005.An application is given to illustrate the functions of the software.In Chapter 6, the conclusions of the dissertation are summarized and future research of form tolerance modeling and error evaluation is prospected.