June 18, 2014 | David F. Coppedge

Man Climbs Glass Like a Gecko

Bio-inspired technologies are starting to reach the market.

Gecko Pads

A heavy man with a pack climbed up a sheet of glass, and it wasn’t Spider-Man.  It was a volunteer testing out new dry adhesive technology inspired by gecko toes.  “During testing, an operator climbed 25 feet vertically on a glass surface using no climbing equipment other than a pair of hand-held, gecko-inspired paddles,”  a press release from DARPA states.  “The climber wore, but did not require, the use of a safety belay.”

DARPA’s Z-Man program has demonstrated the first known human climbing of a glass wall using climbing devices inspired by geckos. The historic ascent involved a 218-pound climber ascending and descending 25 feet of glass, while also carrying an additional 50-pound load in one trial, with no climbing equipment other than a pair of hand-held, gecko-inspired paddles….

Amazing FactsThe goal of the program is to develop biologically inspired climbing aids to enable warfighters carrying a full combat load to scale vertical walls constructed from typical building materials.

“The gecko is one of the champion climbers in the Animal Kingdom, so it was natural for DARPA to look to it for inspiration in overcoming some of the maneuver challenges that U.S. forces face in urban environments,” said Dr. Matt Goodman, the DARPA program manager for Z-Man. “Like many of the capabilities that the Department of Defense pursues, we saw with vertical climbing that nature had long since evolved the means to efficiently achieve it. The challenge to our performer team was to understand the biology and physics in play when geckos climb and then reverse-engineer those dynamics into an artificial system for use by humans.”

Geckos can climb on a wide variety of surfaces, including smooth surfaces like glass, with adhesive pressures of 15-30 pounds per square inch for each limb, meaning that a gecko can hang its entire body by one toe.

The article describes how gecko toes can cling to many surfaces, without glue, using atomic (van der Waals) forces from billions of tiny spatulae on its feet.  One can see many practical applications in the consumer market for this capability.  In addition to “reversible adhesives for potential biomedical, industrial, and consumer applications” mentioned by DARPA, many a kid would love to play Spider-Man or Gecko-Man.

Eye Camera

Another example of biomimetics coming to market was announced by IEEE in a press release: “Sony Creates Curved CMOS Sensors That Mimic the Eye.” Coming soon to a camera or smartphone camera near you will be curved detectors that do a better job at light collection.

The retinas of humans and other animals line the curved inner surface of the eye. Now, in a bit of biomimicry, Sony engineers reports that they have created a set of curved CMOS image sensors using a “bending machine” of their own construction.

The result is a simpler lens system and higher sensitivity, Kazuichiro Itonaga, a device manager with Sony’s R&D Platform in Atsugi-shi, Japan reported on Tuesday at the Symposium on VLSI Technology in Honolulu, Hawaii.

There are several advantages to a curved, retina-like sensor: (1) better light collection, (2) better sensitivity at the edges, and (3) less noise per pixel.  “All told, the curved systems were 1.4 times more sensitive at the center of the sensor and twice as sensitive at the edge, according to the Sony engineers.”

PhysOrg said no dates have been provided for when the curved sensors will appear in Sony products, but the buzz is that it could be soon.  One photography blog said it promises to be “an impressive leap forward in digital imaging technology.”  Perhaps it would be better described as an impressive leap backward to technology that was already there.

Other Biomimetics News

  • Spider venom inspires bee-safe pesticide (Science Magazine)
  • It’s springtime for the artificial leaf at Caltech (Nature)
  • Understanding mussels’ stickiness could lead to better surgical and underwater glues (American Chemical Society)

The Naysayer

Are humans better inventors than nature?  “Simply copying nature is no way to succeed at inventing,” David Taylor challenged on The Conversation.  “Just ask Leonardo da Vinci” whose attempts to copy bird flight never got off the ground.  Taylor sees “bio-inspired engineering” only as a heuristic start.  “At some point you have to give up the love affair, dump nature and move on,” he says.  “The problem is that simply copying nature doesn’t work.”  In human engineering design, he argues, we cannot endure the failure rate nature tolerates, like fractured bones or breaking tree limbs.  Some designs that inspire engineers don’t scale well, he adds.  A tiny mite that runs faster than a cheetah in terms of body lengths per second.  Humans, though, are more interested in absolute speed, not relative speed, so that knowledge is not very practical for engineers.  “Nature can be a wonderful muse, an excellent starting point in the development of a new engineering device or material, but don’t make the mistake of thinking that nature has already solved your problems for you,” he ends.  While he may have a point, the gold rush from engineers bringing bio-inspired devices to market may leave him muttering to himself in their dust.

Let’s see Taylor do anything that nature does better.  Let’s see him invent something that mimics a living organism, that develops itself from an internal program, lives off the environment, and makes copies of itself.  If the efficiency, robustness and optimization of nature’s designs were not so good, then whole university departments and companies would not be rushing to copy them.  The better way to express his point is that human engineers have to make compromises that nature does not.  We have to take shortcuts to make cheap imitations of nature’s designs.

We apologize for cluttering the Amazing Facts award with DARPA’s dumb remark, “nature had long since evolved the means to efficiently achieve it.”  We cannot take responsibility for the bad habits of our sources.


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