We propose a number of "divergence metrics" to
quantify the robustness of a trajectory to state uncertainty
for under-actuated or under-sensed systems. These metrics are
inspired by contraction analysis and we demonstrate their
use to guide randomized planners towards more convergent
trajectories through three extensions to the kinodynamic RRT.
The first strictly thresholds action selection based on these
metrics, forcing the planner to find a solution that lies within
a contraction region over which all initial conditions converge
exponentially to a single trajectory. However, finding such a
monotonically contracting plan is not always possible. Thus, we
propose a second method that relaxes these strict requirements
to find "convergent" (i.e. low-divergence) plans. The third
algorithm uses these metrics for post-planning path selection.
Two examples test the ability of these metrics to lead the
planners to more robust trajectories: a mobile robot climbing
a hill and a manipulator rearranging objects on a table.
This work was supported by the Toyota Motor Corporation.
BibTeX entry
@article{paper:johnson_convergent_2016,
title = {Convergent Planning},
author = {Aaron M. Johnson and Jennifer E. King and Siddhartha Srinivasa},
year = {2016},
journal = {IEEE Robotics and Automation Letters},
volume = {1},
number = {2},
pages = {1044--1051}
}