# pic: 612 Teaser #2

I Promise this is the last teaser, the next photo from us will be the full assembly. Until then you can try to figure out what we are doing.

Based upon the variety of ways that a team can score points in this year’s game, I am going way out on a limb here but I am using partial differential calculus and linear algebra to verify my hypothesis so if I am off target please understand:rolleyes:

You have a four-wheel drive with a crab type steer on the front wheels.
You are harvesting moon rocks and empty cells off the floor via a conveyor system using belts.
You then store them in a shelf type hopper and it gets real tricky with this next part but you are either going to dump or shoot them into the trailer.

I’ll wait to see your next picture to learn how close I am with this wild assumption:D

Seriously, It is a clean looking frame and I am very interested to see your hopper / scoring mechanism.

APS

Almost got it! Except we have a hybrid of shooting and dumping . Once it is all assembled and we start fine tuning it we will post some videos which will explain more.

Steering is via front wheel Ackermann, using independent steering motors with shaft encoders on the steering axes. (There wasn’t enough space to use the standard mechanical Ackermann link.) Each drive wheel has a quadrature encoder to ensure we get the correct wheel speed while turning.

Here’s a sketch of the system’s geometry, and the trig functions we are using in LabVIEW:

http://www.chantillyrobotics.com/team/documents/2009/steering-angle.jpg

We use the inside front wheel’s steering angle to drive the outside wheel’s angle, and the outside front wheel speed to drive the other 3 wheels’ speeds.

Using LabVIEW, these calculations were quite easy. It’s an excellent tool, and a real time saver.