The invention relates to the field of computer-aided
engineering, in particular to an MBD-based
assembly error automatic modeling method. The method comprises the steps that firstly, an
assembly relation graph is used for storing the
assembly relation, the assembly sequence and the assembly hierarchy of parts in an assembly body; secondly, the geometric feature positioning
relation graph is used for determining a reference-target relation between feature surfaces in the parts in the assembly
relation graph; then, establishing a reference coordinate
system of each geometric feature, and defining correct positions of the geometric features under the reference coordinate
system according to the theoretical size; and finally, converting the graph into an error propagation chain according to the geometric feature position hierarchical
system, determining the actual position of the geometric feature, and calculating a spatial dimension chain according to the actual position. The method provides a solution for realizing 3D
tolerance analysis based on the model, and has the advantages of less man-
machine interaction operation, high calculation precision and the like. The tolerance can be conveniently defined and managed in CAD
software, and the establishment of a tolerance model is realized.