Robot design has come a long way in the last few years and newer and more radical designs are popping out of the woodwork. However, a new type of robot may see some use in space missions to come. The new robot involves a multi-legged design that allows it a climb up walls. The robot moves in a manner reminiscent of a gecko and is envisioned to crawl along the hulls of spacecraft for cleaning, repairs and general maintenance.
The current prototype, called Abigaille, has been developed by researchers from ESA and Simon Fraser University in Canada. It is a small machine but future designs could be scaled up or down depending on the need. The prototype's tiny legs have pads covered with dry microfibers that allow it to stick to surfaces.
Tiny hairs called setae on the footpads of some lizards allow them to walk along walls and other vertical surfaces. This was what inspired scientists to create the microfiber footpads on the new robot. This works through the action of van der Waals force in which the tiny hairs "stick" to a surface due to molecular attraction. While the scientists were successfully able to mimic nature, the microfiber hairs on the robot are actually a hundred times larger in diameter compared to the natural hairs that grow on a gecko's foot. While larger in diameter, the fibers can still do the job adequately. Scientists have long been looking for materials that could manage the feat but they learned early on that traditional adhesive materials proved inadequate.
"Scotch, duct or pressure-sensitive tape would collect dust, reducing their stickiness over time. They would also give off fumes in vacuum conditions, which is a big no-no because it might affect delicate spacecraft systems," said Michael Henrey, a graduate student at Simon Fraser University.
"Velcro requires a mating surface, and broken hooks could contaminate the robot's working environment. Magnets can't stick to composites, for example, and magnetic fields might affect sensitive instruments," Henrey, who tested Abigaille in ESA's Electrical Materials and Process Labs, based in the Agency's ESTEC technical center in Noordwijk, the Netherlands, with additional support from ESA's Automation and Robotics Lab, said.
"It's very expensive to upgrade hardware once it is up in space so the idea would be to fly a more general robot in the first place," said ESA's Laurent Pambaguian. "This could then be adapted through software upgrades for different tasks that weren't anticipated at the start of the project.
"Our Abigaille climbing robot is therefore quite dexterous, with six legs each having four degrees of freedom, so it should be handle environments that a wheeled robot could not," Pambaguian added.
Given the recent cooling malfunction in the International Space Station, robots like these could be very useful and keep human astronauts safely inside the station while the robots do all of the dangerous work outside.
So far, testing has been conducted on smooth surface. However, an exploratory variant of this robot would need to be able to manage moving across a wide variety of terrain and the scientists on the project intend to design variants that could handle a variety of different surfaces.
