This paper presents CC Steer, a steering method for car-like vehicles, ie an algorithm planning paths in the absence of obstacles. CC Steer is the first to compute paths with (a) continuous curvature, (b) upper-bounded curvature, and (c) upper-bounded curvature derivative. CC Steer also verifies a topological property that ensures that when it is used within a general motion planning scheme, it yields a complete collision-free path planner. The coupling of CC Steer with a general planning scheme yields a path planner that computes collision-free paths verifying the properties mentioned above. Accordingly, a car-like vehicle can follow such paths without ever having to stop in order to reorient its front wheels. Besides, such paths can be followed with a nominal speed which is proportional to the curvature derivative limit. The path computed by CC Steer are made up of line segments, circular arcs and clothoid arcs. They are not optimal in length. However, it is shown that they converge toward the optimal 'Reeds and Shepp' paths when the curvature derivative upper-bound tends to infinity. The capabilities of CC Steer to serve as an efficient steering method within two general planning schemes are also demonstrated.

No abstract

This paper presents a set of paths, called bi-elementary paths. These paths are smooth and feasible .for a car-like robot (i.e. their tangent direction is continuous nncl they respect a minimum turning radius constraint), nnd they can be followed by a real vehicle without stopping (i.e. they have a continuous curvature profile) -which is not the case of Dubins' curves. These paths are composed o j arc8 of clothoid (a clothoid is a curve whose curvature is a 1inea.r fumction oj its arc length), and are used to define a, simplified, i.e. non complete, planner. This simplified planner is, in turn, used in two global planning schemes, na.me1y the Ariadne's Clew algorithm and the Probabilistic Puth Planning. This paper proves a n important property of the bi-elementary palhs, from which the completeness of the two global planners is deduced. 0-7803-361 2-7-4/97 $5.00 0 1997 IEEE

No abstract