Wednesday, December 21, 2011

Reinventing the Wheel Using Contructal Law

Speaking of reinventing the wheel (the omni-wheel), I was recently reading an article by Adrian Bejan, a Distinguished Professor of Mechanical Engineering at Duke University.  In the article he surmises that common wisdom is wrong and nature did indeed invent the wheel, not humans.  As a matter of fact, most early humans failed to recognize the properties of the wheel that were happening with bi-pedal motion.  But, there were a few shining stars, as evidenced by Da Vinci's Vitruvia (or the Homer version shown), who recognized the cyclical motion of legs.  (Based on his article, Adrian insists that the wheel was not copied from nature and is in no way a form of biomimicry.  Instead, it is an artifact "of our own evolutionary design for moving our mass on the landscape.")

Although the article makes a great case regarding the evolutionary design of the wheel, I was more interested in his continued reference to constructal law.

The Constructal Theory

Prof. Bejan has a web Portal for Constructal Theory.  It's not much to look at (at the time of this writing) but buried within the hot pink boxes are loads of information regarding contructal law.

I would love to sum up constructal theory here, but I'm afraid that is just not possible.  The multitude of examples on his website where contructal law can be used is nothing short of astounding: making biology and economics like physics; sports; technology; social interactions; web (SEO) traffic; and many many others.  It is hard to tell if Adrian is an engineer or something else.  To be able to take a single unifying law and apply it to any number of areas of study is something I think theoretical physicists would like to have for the universe.

I urge you to open your mind a take a look at the constructal theory web portal.  As Adrian concludes in the article I read, the best way to describe constructal law is that it unites animate and inanimate design phenomena and therefore allows the study of evolution within our lifetimes, not the eons it takes in nature.  Fascinating.

Tuesday, December 20, 2011

Wheels. That Rotate. On Wheels.

Every so often you see or read about a technology that is intriguing, if for no other reason than a novelty.  Then, you happen across it again and realize the subtle details of engineering required to make the novelty function.  And then, you see it in action and you realize it deserves more attention than you originally paid.
Image courtesy of Grabcad.
The Omni-Directional Wheel
The omni-directional wheel was first conceived by Swedish engineer Bengt Erland Ilon in 1972.  (SHHHH. Don't tell any Norwegians a Swede invented something first.)  The patent traded hands a few times before the technology finally developed into something product-worthy that first shipped around 2005.  It was a material handling truck (aka forklift or lift truck) called the Sidewinder, produced by Airtrax.
Image from Airtrax website.

At first glance, this wheel looks like it would provide for a very bumpy ride as the load is transferred from roller to roller.  But, as shown in the embedded video, the wheel provides a startling smooth ride. 
The control is a combination of MOSFET, sensor technology, closed-loop feedback, regenerative breaking, speed control, onboard diagnostics, and traction control.  I remember as a tool designer making a moving assembly line with A.N.T's (Adaptable kNeel-down Transporter) that had standard casters on them.  It was very difficult to move that platform through the factory.  What I wouldn't give to be able to redesign that system using wheels and controls from Airtrax.

Most people say that there is no value in reinventing the wheel, but thanks to Bengt and the team at Airtrax, it appears that a reinvented wheel has great potential in the material handling, robotics, and assembly line industries.