关键词: 数字孪生, 产品几何技术规范, 非理想表面模型, 模型表达, 映射生成方法

Abstract: The product digital twin model is considered to achieve a deep integration of physical world and virtual world as a potential effective solution.Aiming at the practical application requirements of a reasonable and accurate digital twin geometrical model in the product life cycle,a geometrical reference representation method based on non-ideal skin model for realizing the digital twin model was proposed.Through introducing new-generation Geometrical Product Specifications (GPS),a complete representation scheme of digital twin model was defined by using geometrical feature and the related operator.Meanwhile,the two mapping generation methods and creation process of digital twin-oriented product non-ideal skin model were analyzed.On this basis,the specification skin model was generated by adding geometric error information to the discrete mesh CAD model.According to the idea of reverse modeling,the verification skin model was generated by multi-scale representation of surface topography errors using the method of discrete geometry and wavelet analysis based on discrete point cloud data of real measurement.The feasibility of the proposed method was verified by a case analysis of part instance.

Key words: digital twin, geometrical product specifications, non-ideal skin model, model representation, mapping generation method