Optimal grid-free path planning across arbitrarily-contoured terrain with anisotropic friction and gravity effects
Rowe, Neil C.
Ross, Ron S.
MetadataShow full item record
Anisotropic (heading-dependent) phenomena arise in the "two-and-one-half-dimensional" path-planning problem of finding minimum-energy routes for a mobile agent across some hilly terrain. We address anisotropic friction and gravity effects, and ranges of impermissible-traversal headings due to overturn danger or power limitations. Our method does not require imposition of a uniform grid, nor average effects in different directions, but reasons about a polyhedral approximation of terrain. It reduces the problem to a finite but provably-optimal set of possibilities, and then uses A* search to find the cost-optimal path. However, the possibilities are not physical locations but path subspaces. Our method exploits the surprising insight that there are only four ways, mathematically simple, to optimally traverse an anisotropic homogeneous region: (1) straight across without braking, the standard isotropic-weighted-region traversal; (2) straight across without braking but as close as possible to a desired impermissible heading; (3) making impermissibility-avoiding switchbacks on the path across a region; and (4) straight across with braking. We prove specific optimality criteria for transitions on the boundaries of regions for each combination of traversal types. These criteria subsume previously published criteria for traversal of isotropic weighted-region terrain. Our method can take considerably less computer time and space than previous methods on some terrain; at the same time, we believe it is the first algorithm to provide truly optimal paths on anisotropic terrain.
This paper appeared in IEEE Transactions on Robotics and Automation, 6, no. 5 (October 1990), 540-553. The equations were redrawn in 2008.
Showing items related by title, author, creator and subject.
Alexander, Robert S.; Rowe, Neil C. (Monterey, California. Naval Postgraduate School, 1990-05);Finding optimal paths for autonomous robots can significantly reduce travel or energy costs or the probability of accident compared to other "reasonable" paths. But finding optimal paths requires a thorough and systematic ...
Kindl, Mark R.; Rowe, Neil C. (Monterey, California. Naval Postgraduate School, 2012-03);This paper describes an efficient stochastic algorithm for planning near-optimal paths for a point agent moving through twodimensional weighted-region terrain from a specified start point to a specified goal point. ...
Obtaining Optimal Mobile-Robot Paths with Non-Smooth Anisotropic Cost Functions Using Qualitative-State Reasoning Rowe, Neil C. (Monterey, California. Naval Postgraduate School, 1997-06);Realistic path-planning problems frequently show anisotropism, dependency of traversal cost or feasibility on the traversal heading. Gravity, friction, visibility, and safety are often anisotropic for mobile robots. ...