Finding curvature-constrained paths that avoid polygonal obstacles

We describe an algorithm to find a unit-curvature path between specified configurations in an arbitrary polygonal domain. Whenever such a path exists, the algorithm returns an explicit description of one such path in time that is polynomial in n (the number of features of the domain), m (the precision of the input) and k (the number of segments on the simplest obstacle-free Dubins path connecting the specified configurations). Our algorithm is based on a new normal form for unit-curvature paths and a dynamic path filtering argument that exploits a separation bound for distinct paths in this normal form.The best result known for the feasibility of bounded-curvature motion in the presence of arbitrary polygonal obstacles involves a reduction to the first-order theory of the reals. It just determines if a feasible path exists (it does not return a path) and requires exponential time and space.