Mobile manipulation
Load equalization via proprioceptive force feedback
Our latest research with Pepe, our PR2 robot from Willow Garage, has focused on manipulating bulky objects for which prehensile grasping strategies may be infeasible: in such cases, we may be able to constrain manipulated objects only unilaterally in some directions.
We recently focused on equalizing bulky loads applied to the PR2’s arms, which would be useful for humanoid dynamic balancing and reducing robot energy consumption. Our simple and robust reactive strategy uses proprioceptive force feedback and manipulation with the arms (not the grippers) to yield exceptional performance: the robot never fails to equalize a load in over 75 experimental trials.
Videos:
- [equalize-box.wmv] (4MB) Equalization of a cardboard box
- [equalize-pipe-variablecom.wmv] (11MB) Equalization of bulky object with changing center-of-mass We change the center-of-mass using small magnetic weights.
- [equalize-pipe-variablecom3.wmv] (15MB) Equalization of bulky object with changing center-of-mass We add weight well outside the polygon of support.
- [equalize-backpacks.wmv] (22MB) Equalization of non-rigid loads
Relevant publications:
- Roxana Leontie, Evan Drumwright, Dylan Shell, and Rahul Simha. Load Equalization on a Two-Arm Robot via Proprioceptive Sensing". Proc. of 13th Intl. Symp. on Experimental Robotics (ISER). Quebec City, Canada. June, 2012. [Powerpoint slides]