* IEEE Robotics and Automation Letters, vol. 2, no. 4, pp.
2209-2216, October 2017 * Pre-print of article appearing in 2017 IEEE Robotics and Automation
Letters. v2: incorporated reviewer feedback Access Paper or Ask Questions
* 8 pages, 10 figures. Accepted by International Conference on Robotics
and Automation (ICRA) 2017. This is the submitted version. The final
published version may be slightly different Access Paper or Ask Questions