Extension of reeds and shepp paths to a robot with front and rear wheel steer

Abstract

This paper presents an algorithm for extending RS paths for a robot with both front and rear wheel steer. We call such robots as FR steer. The occurrence of such paths is due to the additional maneuver possible in such a robot which we call parallel steer, in addition to the ones already present in a vehicle with only front wheel steering. Hence we extend the optimal path set / , containing only a single element to a set : , containing n elements, thereby extending its configuration set along the optimal path from the initial to the final configuration. This extension of the set / to set : is made possible by introducing a special set, which we call the Parallel Steer (PS) Set. Such an extension of the configuration set would increase the size of the final configuration set achievable by a path that is optimal in free space. In the following discussion, we shall term all paths whose length is equal to an RS path as optimal.