Friday, June 6, 2008

Faster Stronger - what the exoskeleton is really about.

What is an exoskeleton really? No, not the type arthropods have....

It is a robotic suit of sorts. A framework, a skeleton if you will, that goes around a human and is attached to him mechanically. It is designed to move with the human, to inhibit his movement as little as possible. And it has actuators of its own - motors, artificial muscles or anything else will do. And here is the interesting part: It acts in concert with the human inside it. Its actuators push and pull and move the skeleton, and the human within, in the same way the human wants to move... The result? Increased strength, speed and endurance. A human with a mind and a body that is completely normal but with physical capabilities well into the extraordinary. A marriage of human intelligence, adaptability and dexterity to the cold calculating power and strength of steel machine.

That's the premise at any rate. If you want more wiki is always at hand: linky

Making one that really works, however, is quite the challenge. Why? Pull your engineer hat on and think that over:

You need to have a steel suit that is really strong, it should be capable of allowing fairly free motion. Thats medieval Knight right there (and contrary to popular belief, even full plate suites were not very restrictive at all). Now strip away the cosmetic parts and the parts that are there for protection and not structural integrity. Done? Good. Now replace the materials with something modern - stronger and lighter that whatever it was those smiths of old wrought their creations out of. Easy enough... but it starts getting harder now. Now, you have to re-tool the system to allow maximum flexibility while insuring the complete and total safety of the wearer. At no point should a stray signal somewhere cause a chain of events that could hurt the user. And that has to be built in to the mechanical structure itself. Now take that system and push it to the limits of its structural design. Use every fancy tool in your arsenal to strip weight without sacrificing strength. Now, attach a set of motors (or whatever) at every joint. Motors that are geared to be fast enough while providing enough force to meet its requirements. They have to be light, efficient, safe and placed perfectly. Attach straps, pads, make sure the joints are perfect and so on and so forth and voila! You have just completed the first tiny step towards making something like this work!

Now come the tricky bits, the ones I work on: Making it all work. In essence, making a lump of joints, steel and actuator walk run and throw like the man strapped into it. i.e. The sensing and control schemes.

I will not bore you with the details of how that works (There are publications and papers plenty for that purpose). What I will tell you is what the control system needs to do:

It needs to sense that the man intends to do (a fraction of a second before he intends to do so if it can be helped). Sense exactly which joint he intends to flex, to what extent, with what strength and with what speed. And then compute what all the many motors and joints need to do to firstly not restrict his motion and secondly (and this is the crux of it all) to aid him by enhancing his speed and strength while he performs that motion.

It is a difficult, difficult task. Even more so when the problems we face in a real world are glimpsed at!

So whats the point of it all you might ask? Why take the trouble? Sure, it might help soldiers survive, workers heft titanic weights, the elderly and the infirm move like the rest of us and make the jobs that firefighters and rescue workers do easier and safer... but is the trouble really worth it? We do fine as we are don't we?

In response to that I shall tell you a little tale. A tale about an animal:

The animal we talk about was born a few hundred thousand years ago. Perhaps a million, but not very much longer than that. It was different. Different from all that had ever come before it in the three billion years his decedents would trace his ancestry through time. Monsters had preceded him. And agile, beautiful creatures too. But he was different from them all. He was the first of us.

We have, since our roots in sub-Saharan Africa, spread out and conquered a world. We dominate it. We are its masters in many, many ways. It is our home and we have made it ours. And how have we done so? Not by strength, not by speed and endurance. Not by any physical attribute of ourselves but by the power of the mind within us. We have made ourselves strong and deadly by the weapons we forge. We have made ourselves faster by the vehicles we make. We have built citadels to stand in for the Armour nature denied us. We bridge the skies and the oceans and the lands of all Earth like no other animal. We are, in our entirety, the strongest, fastest, toughest and most powerful of all the beings that have ever called Terra 'home'.

That is what this is all about. The exoskeleton is just one more step towards us becoming better. One closer to ourselves, our very persons, than any before.

1 comment:

Anonymous said...

Smells good. :)