Robot grippers imitate gecko feet to help nab space junk | Science News for Students

Robot grippers imitate gecko feet to help nab space junk

Engineers tested the sticky technology on a giant air hockey table and in low gravity
Jul 28, 2017 — 7:00 am EST
gecko gripper

Aaron Parness of NASA’s Jet Propulsion Laboratory poses like Superman to grab a floating cube with a gecko-inspired gripper. He’s on an airplane that can temporarily make passengers weightless.

H. Jiang et al/Science Robotics 2017

Get a grip. A new robotic gripping tool can grab floating objects in low gravity. The grippers could one day help robots clean up dangerous space junk or assist them in climbing around the outside of space stations. A new trick for doing this in the absence of gravity: mimicking gecko feet.

Ordinary glue and tape don’t work once you leave the planet. In fact, most adhesives don’t work in space. Glues can’t withstand the wide range of temperatures. And suction doesn’t work, since space is a vacuum.

But a different sticky trick might workt. Geckos are lizards that easily climb walls. Their feet don’t feel sticky. But they cling to surfaces using weak attractions between molecules known as van der Waals forces.

Mark Cutkosky has been working on stickers like this for more than a decade. He designs robots and other devices at Stanford University in California. Now his team has built robotic gripper “hands” inspired by geckos. These hands can grasp objects many times their size without pushing them away. The researchers described their results June 28 in Science Robotics.

The team first tested its grippers in the Robo-Dome. This is like a giant air hockey-table at NASA’s Jet Propulsion Laboratory in nearby Pasadena. One 370-kilogram (815-pound) robot gently pushed another around using a small square of gecko gripper.

Then, last summer, the gecko gripper took flight. Aaron Parness works at of the Jet Propulsion Lab. He and his colleagues tested the full gripper hand aboard NASA’s Weightless Wonder aircraft. This plane flies in steep up-and-down arcs, like a roller coaster. Each time it plunges, the people on board are briefly weightless.

The complete gripper hand has several patches of gripping material in an arrangement that lets them stick to smooth surfaces with just a light touch. Gripper hands could be used to repair or move dead satellites, Parness says. Or gripping parts could help miniature satellites called CubeSats hitch a ride on larger spacecraft.

The team used the hand to grab and release a cube, cylinder and beach ball. These represent some of the different types of junk that now litter outer space. Space junk includes all of the old rocket parts and other no-longer-useful stuff people have launched into space. In all, there may be hundreds of millions of bits — some tiny, others the size of refrigerators. If pieces of this junk collide, they could break into smaller pieces. And even tiny pieces can be dangerous to useful spacecraft or to astronauts on the space station.

A gecko’s sticky feet have inspired space gadgetry.
K. HICKMAN/STANFORD NEWS, H. JIANG ET AL/SCIENCE ROBOTICS 2017, BDML STANFORD UNIVERSITY

Power Words

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arc     A curve, often mapping out what appears to be part of a circle.

astronaut     Someone trained to travel into space for research and exploration.

chemical     A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O.

colleague     Someone who works with another; a co-worker or team member.

force     Some outside influence that can change the motion of a body, hold bodies close to one another, or produce motion or stress in a stationary body.

gecko     A small to medium sized reptile found in warm to equatorial regions of the world. Some 2,000 different species of this lizard exist, in a wide range of colors. These reptiles eat insects, worms and even the occasional small bird. But they are best known for being able to climb slick surfaces, owing to special structures on the bottom surfaces of their feet.

glue     A sticky substance that attaches one material to another.

gravity     The force that attracts anything with mass, or bulk, toward any other thing with mass. The more mass that something has, the greater its gravity.

lizard     A type of reptile that typically walks on four legs, has a scaly body and a long tapering tail. Unlike most reptiles, lizards also typically have movable eyelids. Examples of lizards include the tuatara, chameleons, Komodo dragon, and Gila monster.

molecule     An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound. Molecules can be made of single types of atoms or of different types. For example, the oxygen in the air is made of two oxygen atoms (O2), but water is made of two hydrogen atoms and one oxygen atom (H2O).

NASA     Short for the National Aeronautics and Space Administration. Created in 1958, this U.S. agency has become a leader in space research and in stimulating public interest in space exploration. It was through NASA that the United States sent people into orbit and ultimately to the moon. It also has sent research craft to study planets and other celestial objects in our solar system.

planet     A celestial object that orbits a star, is big enough for gravity to have squashed it into a roundish ball and has cleared other objects out of the way in its orbital neighborhood.

propulsion     The act or process of driving something forward, using a force. For instance, jet engines are one source of propulsion used for keeping airplanes aloft.

robot     A machine that can sense its environment, process information and respond with specific actions. Some robots can act without any human input, while others are guided by a human.

rocket     Something propelled into the air or through space, sometimes as a weapon of war. A rocket usually is lofted by the release of exhaust gases as some fuel burns. (v.) Something that flings into space at high speed as if fueled by combustion.

satellite     A moon orbiting a planet or a vehicle or other manufactured object that orbits some celestial body in space.

tool     An object that a person or other animal makes or obtains and then uses to carry out some purpose such as reaching food, defending itself or grooming.

vacuum     Space with little or no matter in it. Laboratories or manufacturing plants may use vacuum equipment to pump out air, creating an area known as a vacuum chamber.

van der Waals forces     A type of molecular attraction that works over very small distances.

Citation

Journal: H. Jiang et al. A robotic device using gecko-inspired adhesives can grasp and manipulate large objects in microgravity. Science Robotics. Published online June 28, 2017. doi: 10.1126/scirobotics.aan454.