Qualitative rigid-body mechanics

摘要

We present a theory of qualitative rigid-body mechanics and describe a program that uses this theory to compute qualitative rigid-body dynamic simulations. The program works directly from a qualitative representation of geometry—qualitative configuration space—without need of any metric information. The program can handle devices that are composed of an arbitrary number of fixed-axis components and springs, with driving inputs coming from both applied motions and forces. The program employs quasi-static assumptions, i.e., inertia-free motion, inelastic collisions, and frictionless contacts. It employs a new qualitative representation for forces that reduces ambiguity in force sums and hence reduces unnecessary branching.