Kinodynamic Motion Planning on Vector Fields using RRT*

Abstract

This report presents a methodology to integrate vector field based motion planning techniques with optimal, differential constrained trajectory planners. The main motivation for this integration is the solution of robot motion planning problems that are easily and intuitively solved using vector fields, but are very difficult to be even posed as an optimal motion planning problem, mainly due to the lack of a clear cost function. Examples of such problems include the ones where a goal configuration is not defined, such as circulation of curves, loitering, road following, etc. While several vector field methodologies were proposed to solve these tasks, they do not explicitly consider the robot's differential constraints and are susceptible to failures in the presence of previously unmodeled obstacles. To add together the good characteristics of each approach, our methodology uses a vector field as a high level specification of a task and an optimal motion planner (in our case RRT*) as a local planner that generates trajectories that follow the vector field, but also consider the kinematics and the dynamics of the robot, as well as the new obstacles encountered by the robot in its workspace.