Building models for qualitative prediction of system dynamic behavior

The authors present a method of automatically constructing a model or a set of constraints from domain principles for solving the dynamic behavior of a mechanical system through qualitative simulation. The following issues are emphasized: (1) the extraction of a necessary and sufficient set of system constraints which provides the minimum uncertainty associated with qualitative simulation, and (2) the modification of system constraints through time by detecting and identifying 'system discontinuities'. The first is accomplished by describing a mechanical system by a collection of object and inter-connection primitives, which allows selection of the final set of constraints having the minimum complexity and uncertainty, based on the A* algorithm with heuristics providing the problem solving expertise. The second is accomplished by monitoring whether the states of any individual subsystems evolve to system discontinuities represented by intra/inter subsystem critical states.<>