Adhesion, MobileManip

I would use the numbered Heading1 stuff for things that will make sense in the TOC -mrc

1.  Vision

We are working in collaboration with the Stanford Autonomous Systems Lab and the Intelligent Robotics Group at NASA Ames on an Early Stage Innovations grant. We plan to equip Assistive Free Flyers (AFFs), small robots aboard the International Space Station, with gecko-inspired gripper appendages to aid astronauts.

Free fliers use adhesive grippers to manipulate objects in the ISS

2.  Grasping with Gecko-Inspired Adhesives

Lifting a bag of water
using only shear forces

Gecko-inspired adhesion is capable of grasping surfaces rather than discrete features on an object. New strategies for grasping and manipulation leveraging this unique ability are being explored. Such grippers require very little force to engage with a surface and can grasp surfaces much larger than their actual span. Our gecko grippers are able to "grasp without squeezing," maintaining a hold on objects without pushing them out of their grasp.

The adhesive material is passive and space-qualified. Versions have undergone environmental testing including exposure to temperatures of −80C, vacuum pressures, and doses of radiation without significantly degrading performance.

3.  Modeling

Initial work on grasping free floating objects has explored landing envelopes on the ASL's free flyer table simulating microgravity in 2D. Bounds on successful acquisition of spinning objects have been established and will in turn guide the design and control behind assistive free flyers. The grippers are tolerant to a spread of conditions on approach angles and velocities. The goal of trajectory planning will be to ensure maneuvers fall within this verified, successful envelope.

Constraints on the gripper's ability to acquire an object include limitations on the minimum incoming linear momentum, and a maximum angular momentum the gripper is able to arrest after contact is made.

4.  Experiments on Stanford Free Flyer Testbed

Grasping experiments are conducted on the Stanford free-flyer test beda 2D microgravity analog consisting of a 3x4 m granite table with a precisely calibrated flat and level surface, on which robotic platforms can drift on air bearings with near-zero friction.

Motion of objects are tracked and recorded to sub-millimeter precision using an OptiTrack motion capture system running at 120 Hz.

5.  Research Team and Collaborations


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2015 NASA Early Stage Innovations (ESI) Team

Project Title: Assistive Free-Flyers with Gecko-Inspired Adhesive Appendages for Automated Logistics in Space

Related groups within the program:


!! News

6.  Publications

Estrada, M., Jiang, H., Noll, Bessie., Pavone, M., and Cutkosky, M.R., "Force and Moment Constraints of a Curved Surface Gripper and Wrist for Assistive Free Flyers," 2017 IEEE International Conference on Robotics and Automation (Accepted)

Estrada, M., Hockman, B., Bylard, A., Hawkes, Elliot Wright., Cutkosky, M., Pavone, M., "Free Flyer Acquisition of Spinning Objects with Gecko-Inspired Adhesives," 2016 IEEE International Conference on Robotics and Automation (preprint)

7.  Links

For space junk grasping and recycling, see Space Gripper for Large Loads.

Page last modified on May 19, 2016, at 01:13 AM