关键词: 夹具, 定位误差分析, 定位误差要素, 平面连杆机构, 概率分析

Abstract: General analysis method of fixture positioning error in planar positioning process was studied.There were four elements related to fixture positioning error in workpiece-fixture system, i.e. machining surface, process datum, positioning datum and locators, which could be indicated by four planar geometry elements：line segment, circle, arc and point. Position of the four elements and the position variation among them were denoted by equivalent planar link mechanism model. All sequence information and interrelationships among them of workpiece-fixture system were represented by structure parameter of link mechanism. Mapping rules from contact pairs to mechanism components were established, and the expression method of mechanism components and kinematic pairs were put forward. According to the rules mentioned above, the positioning error computation model was established automatically. Finally, the positioning error in planar positioning process was calculated by mechanism error probabilistic analysis.

Key words: fixture, positioning error analysis, positioning error elements, planar link mechanism, probabilistic analysis