From Reeds and Shepp's to Continuous-Curvature Paths

ftp://ftp.inrialpes.fr/pub/sharp/publications/fraichard:etal:icar:99.pdf.gz (not accepted here, non vectorial font)Most path planners for car-like robots compute ``Reeds and Shepp paths'' made up of line segments connected with circular arcs. Such paths have a discontinuous curvature that makes them difficult to track (curvature is related to the orientation of the front wheels). The purpose of this paper is to present one of the first path planner for car-like robots that computes paths with continuous-curvature and upper-bounded curvature derivative (curvature derivative is related to the steering velocity). The approach presented herein relies upon a steering method, i.e. an algorithm that computes paths without taking into account the obstacles of the environment, which is then embedded within a general path planning scheme in order to deal with the obstacles and thus solve the full problem. The paths computed are made up of line segments, circular arcs and clothoid arcs