Abstract: A systematic methodology for automatic planning of modular fixture for dowel-pin system is presented. The approach constructs all the feasible fixture plans of a part with linear and circular edges by using the linkage mechanism theory. Based on the geometric relationships between locator triplet and three boundary edges of a part, the loading and unloading motion of the part are classified into two kinds, I.e. translational motion and rotational motion. Moreover the notions of the locator visible cone and the pivotal locator are put forward, and utilized to analyze the accessibility of locators. To effectively analyze the feasibility of clamping the part, and generate all of the feasible clamp positions, the notions of the triangle of instant rotational center and the same direction edge of the triangle are set forth and utilized.

Key words: Accessibility analysis, Clamping analysis, Modular fixture Automated fixture planning