Geckos, Physics and Robotic Grippers

Gecko Gripper works without the cost, complexity and energy consumption of the compressed-air system required by vacuum grippers.

In case you’ve ever wondered, geckos are able to climb walls because there are tiny hairs on their feet that make use of something called “van der Waals” forces, which operate at a molecular level.

In case you’re wondering why you’re reading about that here, bear with us: It may be highly relevant to your manufacturing operations. Seriously.

Van der Waals forces result from the fact that the electrons that orbit the nuclei of atoms aren’t evenly spaced. So a molecule that, as a whole, is neutral in charge will be positively charged on one side and negatively charged on the other. A positive side of a molecule will be attracted by the negative side of an adjoining molecule, and it’s that attraction—not hooks, suction cups or some secreted adhesive—that lets the gecko scamper across vertical surfaces.

Robotic end-effector tooling developer OnRobot (onrobot.com) has taken this and developed what it calls the “Gecko Gripper” for the manipulation of flat, smooth objects with millions of micro-scaled fibrillar stacks that mimic the hairs on the feet of geckos.

For the right applications, a robot gripper using van der Waals attraction offers advantages over other grippers. It works without the cost, complexity and energy consumption of the compressed-air system required by vacuum grippers. Moreover, it isn’t stymied by holes in a workpiece the way a vacuum gripper would be. And it is both stronger and more energy-efficient than electrostatic grippers, which require higher voltage.

“We see the gripper now challenging traditional application and material handling design in a wide range of delicate tasks such as picking up porous and fragile objects like PCB boards,” says Kristian Hulgard, OnRobot’s General Manager for Americas.

The device began as a research project at Stanford University in 2014. The work was taken up by the NASA Jet Propulsion Laboratory in 2015, which resulted in prototype robots designed to work on the outside surface of a satellite in the vacuum of space. Perception Robotics—since acquired by OnRobot—used the technology to begin developing industrial grippers; Perception’s polymer research enables a gripping force five times stronger than what NASA had developed.