Kenematic Tolerance Analysis

We present a general method for worst-case limlt kinematic tolerance analysis: computing the range of variation in the kinematic function of a mecnanism [rom its part tolerance specifications. The method covers fixed and changing contact mechanisms with parametric or geometric part tolerances. We develop a new model of kincmaLic variation, called kinematic tolerance space, that generalizes the configuration space representation of nominal kinematics function. Kinematic tolerance space captures quantitative and qualitative variations in kinematic function due to variations in part shape and part configuration. We derive properties of kinematic tolerance space that express the relationship between the nominal kinematics of mechanisms and their kinematic variations. Using these properties, we develop a practical kinematic tolerance space computation algorithm for planar pairs with two degrees of freedom and for assemblies of such pairs with independent part tolerances. To appear, Computer-Aided Design, September 1996.