齐次坐标在结构可变体系分类中的应用

Applications of homogeneous coordinates in the variable system classifications of structures

引入了欧氏平面上无限远点的二维齐次坐标和直线上无限远点的点坐标及线坐标，引用了与无限远点有关的一些定理及结论于结构的分类中．从而给出了可变体系中的常变与瞬变在结构形式上的区别，完善了杆系平面结构几何组成规则的内容．

By introducing the two dimensional homogeneous coordinates of an infinite point on Euclidian plane,the point coordinates and linear coordinates of an infinite point in straight lines,some theorems and conclusions referred to infinite points are applied in the classifications of structures in this paper.So differences in the structural form between the instantaneous variable structures and the constant variable structures are shown.And the contents of geometrical compositive rules about plane structures of bar system are perfected.