Building models from domain principles

A method of automatically constructing a system model or set of constraints from domain principles for solving the dynamic behavior of a mechanical system is presented. The following issues are emphasized: (1) the extraction of a necessary and sufficient set of system constraints from the fundamental principles and laws of physics based solely on the physical description of a given mechanical system, and (2) the modification of system constraints through time by detecting and identifying `system discontinuities´ due to collisions, separations. and other critical states associated with each system object. The first is accomplished by describing a mechanical system by a collection of object and interconnection primitives. which allows direct invocations and instantiations of all the relevant physics laws from the knowledge base. In consequence, the final constraints are selected on the basis of 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