A Combinatorial Approach for the Automatic Sketching of Planar Kinematic Chains and Epicyclic Gear Trains

Automatic mechanism sketching can be considered to be a computational approach for converting the graph representation of a mechanism into its skeleton diagram representation, subject to the constraint of the avoidance of crossing links. The purpose of sketching is to obtain a clearer understanding of the topological and functional characteristics of a mechanism. Since the avoidance of link crossing alone cannot provide control over the numerical solution to the sketching problem, the graph-to-mechanism conversion process, subject to the constraint of link crossing avoidance, can be classified as an ill-constrained problem. The application of heuristics and semi-algorithmic methods have been applied by a number of authors in an attempt to overcome this numerical barrier. This paper introduces a new computational model, based on a combinatorial approach, for algorithmically solving the numerically continuous mechanism sketching problem as a discrete domain problem. This new approach can systematically generate explicit, concrete sketching constraints, thereby providing a well defined methodology for mechanism sketching.