Will The U.S. Have Spider Soldiers In The Near Future?
Can you imagine soldiers being able to scale a towering vertical glass wall similar to what you see in a Spiderman movie?
And that’s without the benefit of camera tricks or technical effects usually employed in movies to make it look like it’s real.
Joint Efforts: Stanford University Research Team And US DARPA
Researchers and scientists at Stanford University, who are closely working with the US military through the funding of US Defense Advanced Research Projects Agency (DARPA), have developed and created a material which could allow people to ascend a vertical flat wall surface as if it’s a rocky mountain.
Inspired By Gecko Feet
The researchers and scientists took their inspiration from the gripping toes of geckos as they created a climbing device made from silicone pads the size of a hand, on which tiny ridges that can adhere to smooth and flat surfaces are attached. 24 independently suspended tiles covering the 140 square centimeter adhesive area per hand comprise the synthetic adhesion system from which load is transferred to the climber’s foot.
A harness provides support to the weight of a foot rest which is connected to the pads using a pole. Rows of microscopic slanting wedges are attached to the silicone pads which temporarily bond to the glass wall surface when weight is applied.
Gecko-Like Adhesive Pads
This is not the first time that an attempt was made to copy and develop gecko feet technology, but all previous trials failed. The Stanford University scientists had found a way to share the load between 24 postage-stamp sized tiles attached on each pad to allow Elliot Hawkes, a researcher and Stanford University biomimetics student to ascend a 3.5 meter tall vertical glass wall. Hawkes weighs 154lbs. Stanford researchers and scientists are now hopeful that they can develop and fine tune a technology that would allow climbers to move in a faster and smooth fashion.
The researchers are looking at developing gloves very much like the ones used in the movie Mission Impossible – Ghost Protocol, by the character of Tom Cruise to climb up the façade of Burk Khalifa in Dubai – the world’s tallest building.
Past Efforts Ignored Basic Ergonomic Facts
According to a biomimetic engineer at Stanford University and lead researcher, Prof Mark Cutkosky, what have been developed in past efforts are “spider suits” which completely ignored some basic ergonomic issues such as the fact that people have less strength in their arms compared to the strength in their legs.
Considering this flaw, the researchers focused on a system that would use the hands to gently attach and detach the adhesive tile. They put together a system of cables and links that transfer the load to the feet.
DARPA Z Man Project
The adhesive pads which are not sticky and can be reused multiple times were developed as part of the “DARPA Z Man” Project which is aimed at helping US soldiers climb, ascend or scale tall buildings and other obstacles with much ease.
Studying The Way A Gecko Climbs
The researchers studied the climbing ways of the Tokay gecko, a type of lizard found in Asia. They discovered that geckos use setae – tiny bristles on their toes. Each of the bristle is split into nano-sized tips known as septulae and the weak electrical interactions between the surface and the molecules in the septulae provide a hold or grip that permits geckos to even climb upside down. Such observations helped the researchers reach a breakthrough as they were able to develop adhesive pads from polydimethylsiloxane (PDMS) – a silicone material, which are molded into microscopic slanted wedges.
Hand-Sized Silicone Adhesive Pads
The adhesive pads grip the smooth surfaces including:
- Painted metal
These grip the smooth surfaces, including glass, plastic, wood and painted metal, in a similar way to the gecko’s feet when they have a load pulling against the tips of the wedges. Without the weight on the pads, the grip of the adhesive pads on the surface can be removed.
The use of very small tiles which can be produced to the required exactness in size and form using a CNC wire EDM machine, allowed the pads to conform to a surface more easily than if they used a single adhesive surface.
Adhesive Pads That Can Support Human Weight
Hawkes discovered that the pads were allowed to support adult human weight through load sharing made possible by a system of “tendons” and springs. The adhesive pads are said to outperform the geckos in their climbing ability. The researchers recently published their results in the Journal of the Royal Society Interface.
Cutkosky, Hawkes and the rest of the research team believe that the “spider suits” could well be used in other ways beyond climbing walls. The team is also working with NASA to develop technology that would help grasp debris in space, which according to Cutkosky may be possible using the technology on controllable dry adhesives.
This technology does not require suction and works at low temperatures, even without external power. But that’s an entirely different undertaking for the brilliant minds of the Stanford researchers and scientists.