Stanford University scientists have combined gecko-inspired adhesives and a custom robotic gripper to create a device for grabbing space debris.
The device which was tested in multiple zero gravity settings – including the International Space Station – is the outcome of a collaboration with NASA’s Jet Propulsion Laboratory (JPL).
“What we’ve developed is a gripper that uses gecko-inspired adhesives,” said Mark Cutkosky, Stanford professor senior author of the paper. “It’s an outgrowth of work we started about 10 years ago on climbing robots that used adhesives inspired by how geckos stick to walls.”
The gripper is not as intricate as a gecko’s foot – the flaps of the adhesive are about 40 micrometers across while a gecko’s are about 200 nanometers – but the gecko-inspired adhesive works in much the same way.
Like a gecko’s foot, the gripper is only sticky if the flaps are pushed in a specific direction but making it stick only requires a light push in the right direction. This is a helpful feature for the kinds of tasks a space gripper would perform.
The pads further unlock with the same gentle movement, creating very little force against the object.
The gripper the researchers created has a grid of adhesive squares on the front and arms with thin adhesive strips that can fold out and move toward the middle of the robot from either side, as though it’s offering a hug. The grid can stick to flat objects, like a solar panel, and the arms can grab curved objects, like a rocket body.
The group first tested the gripper in the Cutkosky lab. They closely measured how much load the gripper could handle, what happened when different forces and torques were applied and how many times it could be stuck and unstuck.
They later attached small rectangular arms with the adhesive to a large robot at the JPL’s Robodome, then placed that modified robot on a floor that resembled a giant air-hockey table to simulate a 2D zero gravity environment. The robot was made to scoot around the frictionless floor and capture and move a similar robot.
The researchers then went on a parabolic airplane flight to test the gripper in zero gravity. The gripper successfully grasped and let go of a cube and a large beach ball with a gentle enough touch that the objects barely moved when released.
Image, video and content: Kurt Hickman/Stanford University
