PARAMETRIC KINEMATIC TOLERANCE ANALYSIS OF GENERAL PLANAR SYSTEMS

We present an algorithm for functional kinematic tolerance analysis of general planar mechanical systems with parametric tolerances. The alg orithm performs worst-case analysis of systems of curved parts with co ntact changes, including open and closed kinematic chains. It computes quantitative variations and helps designers detect qualitative variat ions, such as blocking and undercutting. The algorithm constructs a va riation model for each interacting pair of parts: a mapping from the p art tolerances and configurations to the kinematic variation of the pa ir. These models generalize the configuration space representation of nominal kinematics to toleranced parts. They an composed via sensitivi ty analysis and linear programming to derive the system variation at a given configuration. The Variation relative to the nominal system fun ction is computed by sampling the system variation. We demonstrate the algorithm on detailed parametric models of a movie camera him advance and of a micro-mechanical gear discriminator. (C) 1998 Elsevier Scien ce Ltd. All rights reserved.