Abstract: Joint surface error is described by small displacement torsors theory, error transfer properties of common assembly joint surface are analyzed. Assembly joint surface symbols with engineering semantics are defined to describe the type of joint surface and cooperate relationship. Combined with the polychromatic sets theory, joint surface and error relationship contour matrix(called joint surface symbols(JSS) matrix) that can describe assembly relationship, joint surface type and error transfer properties is established. Assembly error transfer path search method based on JSS matrix is proposed, the actual error transfer property matrix of joint surface is established, and the method of obtaining the transfer path of each error component is discussed. In view of the uncertainty problem in parallel error transfer path, highest precision is put forward as the basis of distinguishing error transfer effective path, then the effective error transfer paths of error component which is associated with the assembly precision requirements are obtained based on the error model that is established based on Jacobian-torsor theory. The feasibility and practicability of the research method is verified by an example of a typical assembly error transfer path solution.

Key words: error transfer path, Jacobian-torsor method, joint surface symbols matrix, polychromatic sets theory, small displacement torsors theory