基于生成式模型的三维气动外形设计框架

Generative model-based framework for 3D aerodynamic shape design

  • 摘要: 气动外形设计是飞行器设计的重要组成部分。为了加速飞行器气动外形设计效率、克服参数化设计方法在概念设计初期对拓扑结构的限制,辅助设计师快速提出初始候选方案,本文对三维气动外形智能设计问题开展了研究。提出了一种基于生成式模型的三维气动外形设计框架,该框架采用点云形式对三维气动外形进行统一几何表征。首先,构建一个基于自编码器结构的飞行器三维外形几何基础模型,采用自监督方式进行生成式预训练,获得三维气动外形的低维隐向量;然后,搭建嵌入气动性能引导的条件扩散模型,并在隐空间中进行训练,实现三维气动外形隐向量的可控扩散生成,并通过解码器将隐向量解码为点云形式外形。另外,针对气动系数预测任务,在基础模型的解码器基础上添加映射式网络,实现对气动性能进行快速推理预测。对该框架进行了初步验证,结果表明,该框架能够根据气动性能端到端地快速生成大量点云形式的气动外形,生成的点云气动外形可以使用气动性能智能预测模型进行筛选。该框架具有较强的泛化能力,可用于不同构型的三维气动外形生成式设计。

     

    Abstract: Aerodynamic shape design is a critical aspect of aircraft development. To enhance design efficiency, overcome the topological constraints of parametric methods in early conceptual design, and assist designers in rapidly generating initial candidates, this study investigated the problem of intelligent 3D aerodynamic shape design. A generative model-based framework was proposed, which employs point clouds as a unified geometric representation. First, a geometric foundation model based on an autoencoder architecture was constructed and pre-trained in a self-supervised manner to extract low-dimensional latent vectors of 3D aerodynamic shapes. Then, a conditional diffusion model guided by aerodynamic performance was built and trained in the latent space to enable controllable generation of shape representations, which were subsequently decoded into point clouds. Additionally, for aerodynamic coefficient prediction, a mapping network was appended to the decoder of the foundation model to enable fast performance estimation. Preliminary validation of the framework was conducted. The results show that the framework can efficiently generate a large number of point-cloud-based aerodynamic shapes in an end-to-end manner according to target performance, and the generated shapes can be further screened by the aerodynamic performance prediction model. This framework demonstrates strong generalization capability and is applicable to generative design of 3D aerodynamic configurations for various architectures.

     

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