可重用零件特征的快速设计技术

Fast Design Technology of Reusable Part Features

针对零件建模中复杂结构设计重用困难的问题,提出了一种基于网格融合的建模方法。采用离散指数映射(DEM)方法对基网格目标区域进行局部参数化;利用最小二乘网格以特征网格边界为条件进行补洞处理,进而采用DEM方法对补洞网格进行参数化,得到特征网格边界点的参数坐标和法矢;依据参数坐标将特征网格边界映射至基网格目标区域,并以目标区域映射边界点的位置和法矢作为初始形变条件,利用基于层的网格变形优化算法对特征网格进行变形重建,使特征网格具有较好的保形性;通过修正特征网格边界点法矢来控制重建网格体积膨胀收缩情况,进一步提高保形性;依据法矢、曲率对基网络和特征网格提取特征图元并以此添加几何约束,控制特征网格在基网格上的位置形态,保证两网格相对位置关系。实验结果表明:该方法便捷高效、精度高,可在新模型设计中有效实现设计重用。

A modeling method was proposed based on mesh fusion aiming at the problems of having difficulties in reusing complex structural designs in the modeling of parts.Firstly the discrete exponential mapping(DEM)method was used to parameterize the target region of base mesh locally.Secondly the hole filling was conducted on the conditions of boundary of feature mesh by using the least-squares meshes,and then the hole filling mesh was parameterized with DEM to obtain the parameter coordinates and the normals of boundary points of the feature mesh.The boundary of feature mesh was mapped to the target region of base mesh on the base of the parameter coordinates.And the feature mesh was reconstructed with deformations by the layer-based mesh deformation optimization algorithm where the coordinates and normals of the mapped boundary points of the target region were taken as the initial deformation conditions,so that the feature mesh had a better conformality.Then the conformality maybe improved through the correction of the normals of boundary points on the feature mesh to control the expansion or contraction of reconstructed mesh volume.Finally,the feature primitive was extracted from the two meshes according to the normals and the curvatures,and then the geometric constraints were added to control the positions of the feature mesh on the base mesh so as to guarantee the relative position relationship of the two meshes.The experimental results show that the proposed method may be used in the new model design to achieve the reuse of design,which has great convenience,high efficiency and accuracy.