Getting a Grip

By Chelsea Kalberloh Jackson
Tactical Engineering - Tomorrow
Matthew Spenko
Matthew Spenko
Photo: Bonnie Robinson

In the 1960s, “The Jetsons” cartoon creators Hanna-Barbera imagined the outer-space robot housekeeper of the future as Rosie, a sassy didactyl who was mostly successful at keeping the Jetson family’s Orbit City apartment tidy.

Today, truth is arguably just as strange as fiction-considering an inspiration for the engineering behind real twenty-first-century robots able to clean up space debris comes from an unlikely place: the forests of southeast Asia.

Associate Professor of Mechanical Engineering Matthew Spenko and his research team at the IIT Robotics Lab have taken cues from the Asian gecko lizard in their development of a surveillance robot that can climb up and perch on vertical surfaces. NASA hopes the mechanism that enables this robot’s adhesive-like gripping ability can be used with robots designed to remove space junk from low Earth orbit.

“In space there is no suction, and magnetized surfaces can’t be guaranteed,” Spenko says, noting that traditional methods of adhesion are ineffective there. “A typical approach would then be to design a robot that could attach to grapple points on debris. But much of the debris, such as satellites, don’t have grapple points, making it difficult to grasp.”

three-pronged gripper
underside of a gecko’s foot
A three-pronged gripper for grasping flat objects that uses a combination electrostatic/gecko-like adhesive [left] and [right] the underside of a gecko’s foot

NASA estimates that 21,000 pieces of debris (10 cm or larger) are circling Earth, with upwards of 100 million smaller pieces in orbit. In November 2014, NASA controllers raised the orbit of the International Space Station by one mile to avoid the near trajectory of a defunct, junked satellite.

Spenko and his team are researching whether the innovative combination of gecko-like adhesives and electrostatic electrodes that compose their robot’s gripping mechanism could be a debris-remediation solution that sticks. Part engineering and part biomimicry, this mechanism employs what is known as dry adhesion. It involves joining a molded material containing nano-sized hairs-much like the beta keratin setae on the feet of geckos, which are especially adept at gripping smooth surfaces-with charged electrodes whose polarized electrostatic fields create a force that enables the gripping of rough surfaces.

Listen to Associate Professor Matthew Spenko’s take on this in an IIT Magazine Audio Extra.

Used alone, the nano-hairs or the electrodes are limited in the types of surfaces they can attach to. Combined, they result in a gripping mechanism that is not surface dependent and able to hold seven times the robot’s body weight. Spenko says that these grippers also have potential applications in manufacturing, such as on factory lines-anyplace where a better gripping tool might surpass outdated machines.

A focus of Spenko’s Robotics Lab is building robots that achieve mobility in challenging environments, which makes unwieldy surfaces like space junk right up the team’s alley. The team developed HyTAQ, a teleoperated robot that is capable of both flying and rolling over rough terrain (a toy version of the robot is now available on Amazon), and conducts research on how wheeled robots move over various types of soil. The group is currently working with ComEd to develop robots that can supply remote monitoring in areas with unknown terrain.

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IIT Robotics Lab:

Matthew Spenko Audio Extra:

NASA Orbital Debris Program Office: