Study On Specification Design Of Form Tolerance Based On New GPS

The specification design of tolerance is a very important factor to ensure the functional requirement of production. At present, however, the tolerance is largely designed by experience. There is not uniform specification design method which leads to lack of the uniform criterion during the verification process. In order to effectual resolve the current problems of specification design of tolerance, the new generation Geometrical Product Specifications and Verification (GPS) proposed a series of new concept, such as surface model, geometric feature and operator. The specification surface model and specification operator are the important foundations to guide the tolerance design and to achieve the duality principle between the process of design and verification. However, these theories and technologies are still in the conceptual stage. In the new generation GPS standard system, the main researches and contributions of this paper are as follows:Firstly, the researches on the duality principle between the design and verification process in the new generation GPS standard system are given, including the specification design process, measurement and verification process, and the corresponding relation of their surface model and operator.Secondly, according to the basic definition of the specification surface model in the new generation GPS and the requirements of the functional requirements of the parts and the influence on the specification surface model from processing, the generation method of the specification surface model is proposed. The generation method of the single factor of cylindrical and plane surface model is the key research contents. The typical processing of cylindrical and planar are analyzed and the error models are also established. According to this model, the simulation points of the actual part surface can be obtained. By the interpolation and fitting operation on the simulation points, the specification surface model is generated.Thirdly, after the foundation of the specification surface model, based on the characteristics of cylindrical and planar elements, the corresponding operators are designed. The specification operator of cylindrical includes extraction, fitting, integration, fitting, evaluation. The specification operator of planar elements includes extraction, fitting, evaluation. The specification operation on the specification surface model is based on the corresponding algorithm and MATLAB programming. Under the premise of meeting the function requirements, the tolerance design is guided by the maximum deviation of the elements. The specification design processes of cylindrical and planar elements are basically generated.Lastly, specification design prototype system of form tolerance is designed based on the MATLAB. The specification design of flatness, straightness, roundness, axis straightness can be achieved within this system. This system can guide the tolerance design and make the verification process of production more specification.This thesis is financially sponsored by the National Natural Science Foundation of China (Grant No.50865003).