Path Planning for Ground Vehicles

Objective

The objective of this project is to study and devise new means for motion planning for ground vehicles, using Raven as the prototype vehicle. More specifically, we try to determine smooth paths for Raven to follow, as it traverses waypoints; such paths have wide use in applications,  for instance  in following an astronaut as (s)he walks along a random path.

SPLINE BASED PATH PLANNING

We use a special kind of  spline, called PH Spline, as the path for Raven to follow. The PH Spline performs a balancing act between two quantities that determine ideal paths: the path length and the path curvature.  The way in which large ground vehicles follow such a trajectory has not been studied thoroughly before, which is precisely the objective of the current investigation. To determine the effectiveness of the trajectory, we compare the PH spline based trajectory with the default motion planning algorithms extant in ROS. We have  made some encouraging progress thus far.

Raven Executing a P H Spline

APPLICATION : GPS WAYPOINT FOLLOWING

We hare currently extending the above-mentioned PH Spline approach to make Raven follow an astronaut equipped with a GPS. In this experiment, both Raven and the astronaut  have GPS devices that communicate with each other, and Raven attempts to follow him (her) in a smooth path.  The figure below shows a typical graph resulting from this experiment.

 

Raven (red) following astronaut (green) using GPS waypoints, starting from bottom left and going to the top right

Link to PH Spline page