QUALITATIVE KINEMATICS IN MECHANISMS

Reasoning about shapes and their interaction is an important unsolved problem in artificial intelligence. In this paper, we present a theory of qualitative reasoning about kinematic interactions in fixed-axis mechanisms. A key idea of the approach is that a mechanism is represented not by the set of its parts, but by the pairwise interactions between them. Using such symbolic representations of kinematic pairs as the basis for reasoning bypasses the difficult problem of finding a symbolic shape representation which is powerful enough for inferring kinematic properties. We introduce a qualitative representation of the kinematic function of pairs of parts, called a place vocabulary, and show how it can serve as a spatial substrate for envisionments and causal explanations. By composition of place vocabularies, complex mechanisms such as mechanical clocks can be analyzed. © 1990.