Abstract:

To study the influence of parts’ structure symmetry on assembly efficiency, grasping and orienting operations during parts’ assembling process are analyzed, and symmetry features within a part are separately considered and classified into contour and extra-orientation symmetry features. Taking the maximum possible rotating angle of a hexagonal prism part under three different assembling conditions as an example, the concept of total angle of correction (TAC) is proposed based on the existing concept of total angle of rotation (TAR). Using the existing experimental data, a part “symmetry-handling time” prediction model is proposed, which satisfies both the premise of “part’s assembly efficiency increases with its structure symmetry” and the four basic conditions. Four different parts assembly efficiencies are estimated using five different models, and comparing results show that the “symmetry-handling time” prediction model proposed fits the experimental data better and has better discriminability and credibility.

Key words: multi-symmetry features, part assembly time, part symmetry, assembly efficiency