复杂产品涉及多样的技术原理，并且产品结构复杂、影响因素多，客户的需求多变，制造过程也极为复杂。数字孪生技术充分运用模型、数据、仿真等多学科的技术，对于复杂产品的设计与开发、运行和维护具有重要意义。 本文以复杂产品仿真模型建模为切入点，研究基于数字孪生的建模方法与技术，主要研究内容和成果如下： 首先，针对数字孪生系统缺乏统一架构，并且评价方式不明的问题，分析数字孪生系统的构建基础，提出了一种在复杂产品领域较为通用的数字孪生架构。分析研究了数字孪生五维模型，基于架构模型与五维模型分析了数字孪生系统进程评价与要素评价，提出了数字孪生系统的评价流程，对数字孪生系统的整体评价提供方案。 其次，分析数字孪生系统的核心虚拟模型，提出一种虚拟模型架构。并针对其中的仿真模型，定义系统结构状态与模型分辨率状态，提出基于状态图的系统分辨率切换机制，设计了基于系统分辨率的仿真模型切换技术。 再次，研究孪生模型的机理建模与数据建模，分析其优缺点，提出一种基于机理与数据融合建模的孪生模型构建方法，并分析融合模型相较于单一模型的优势。研究了车路协同的仿真案例，验证了机理数据融合建模以及系统分辨率切换机制的有效性。 最后，设计并实现了数字孪生的原型系统。基于实际需求设计孪生系统的具体架构与功能，采用Unity3D软件用机理建模实现了工艺孪生模型的离线与实时仿真，采用python软件用数据驱动建模实现了基于电批数据的故障检测。

Complex products have a series of characteristics such as variable customer demands, complex product structures, diverse technical principles involved, complex manufacturing processes, and multiple influencing factors on products. The digital twin technology fully utilizes multidisciplinary technologies such as models, data, and simulations, which is of great significance for the design, development, operation, and maintenance of complex products. This article takes the modeling of complex product simulation models as the starting point to study modeling methods and technologies based on digital twins. The main research content and achievements are as follows: Firstly, in response to the lack of a unified architecture and unclear evaluation methods for digital twin systems, the construction foundation of digital twin systems is analyzed, and a more universal digital twin architecture in the field of complex products is proposed. Analyzed and studied the five- dimensional model of the digital twin, analyzed the process evaluation and element evaluation of the digital twin system based on the architecture model and five dimensional model, proposed the evaluation process of the digital twin system, and provided a plan for the overall evaluation of the digital twin system. Secondly, analyze the core virtual model of the digital twin system and propose a virtual model architecture. And for the simulation model, define the system structure state and model resolution state, propose a system resolution switching mechanism based on state graph, and design a simulation model switching technology based on system resolution. Thirdly, study the mechanism modeling and data modeling of twin model, analyze its advantages and disadvantages, propose a twin model construction method based on mechanism and data fusion modeling, and analyze the advantages of the fusion model compared with the single model. A simulation case of vehicle road collaboration was studied to verify the effectiveness of mechanism data fusion modeling and system resolution switching mechanism. Finally, a prototype system for digital twins was designed and implemented. Based on actual requirements, the specific architecture and functions of the twin system were designed. Unity3D software was used to achieve offline and real-time simulation of the process twin model using mechanism modeling. Python software was used to achieve fault detection based on batch data using data-driven modeling.