Dean on Dateline Wednesday night

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Posted by Rick Berube.

Engineer on team #121, Rhode Warriors, from Middletown H.S..

Posted on 7/5/99 9:37 AM MST


In Reply to: I'm confused. posted by Daniel on 7/2/99 12:29 PM MST:



: That is beautiful.

: But...I keep staring, and the more I stare, the more confused I get. What if there was a strong gust of wind?? What if a baseball from a game of catch goes wide and hits the back of his chair? Isn't it going to fall?

: It just looks dangerous.

: I'm sure it's not, because Dean is brilliant, but I'd love to know how he does it. Does someone know how this thing works?

:
: -Daniel

Daniel,

the gyrochip measures angular velocity (or angular acceleration). That is, how fast about a point (or shaft for example) something is moving. If you think about the motion as being bi-directional (+ and -), and the point that your rotating about is the shaft of a motor, you can counteract the force off the '35lbs bag of lead' by having that motor apply an equal and force in the opposite direction. If you ever take control theory, this simple tenant will be drummed into your head time and time again. It is basic but at the core of all control systems!
As long as gravity doesn't change or that 35lbs bag doesn't become a 100lbs bag (or whatever weight the chair can no longer compensate for), I assure you it will be safe. But the FDA has many tests the chair must overcome before they allow them to be sold. I'm sure they'll become safer over time too (just like automobiles).

I think the mechanical design is really the amazing thing myself. Although I will admit that this chair wouldn't be possible without computers, electronics and software, to me its the mechanism itself that is awesome. The fact that the machine reconfigures itself effortlessly much like a kids 'Transformer' toy. What is obviously a fairly complex piece of machinery seems to be very stable by designed, yet it has several positions/configurations and terrains/environments in which it must operate.

Remember all those points of physics your engineers/teachers brought up when you were trying to build your robot? Deans chair I'll bet uses all of the same principles, starting with a low center of gravity. Heavy parts (motors/batteries/gears) mounted closest to the ground and I'll bet all the high parts (chair/structure) are strong but light weight. Dean's chair seems to possess the same fine qualities you'll find in most of the successful FIRST robots over the years!

Having said that, do you think the addition of a gyrochip in this year's kit was a coincidence? What about the games themselves over the past several years?

Rick