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Unread 17-05-2016, 00:04
AustinSchuh AustinSchuh is offline
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FRC #0971 (Spartan Robotics) #254 (The Cheesy Poofs)
Team Role: Engineer
 
Join Date: Feb 2005
Rookie Year: 1999
Location: Los Altos, CA
Posts: 803
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Re: FRC971 Spartan Robotics 2016 Release Video

Quote:
Originally Posted by IKE View Post
I noticed looking through the pictures that you started out with a significantly different collector. Judging by the complexity and completeness of the robot, it looks like a pretty late switch to the mecanum style collector. If you could share your reasons and methods, I would love to hear them, and I think a lot could learn. I know I watched videos of your 2012 collector several dozen times a few years ago. Still one of the faster collector/sorter/columnizer mechanisms I have watched.
I'll answer your easy question first and come back to the other ones when I'm not working.

Our initial intake worked well on the bench when prototyped. We tried lifting/lowering the rollers by an inch on the bench, and it seemed to work "ok". When we finally built it, we learned that pneumatic tires bounce even more than we thought, and we would drive up on balls too easily. That was compounded with it being heavy (~16 pounds), and a bit slower than we wanted. The weight was causing the chain to stretch way too fast and even start to yield when we were going over the bumps. (We learned this year to run 35 chain in more spots). It all added up to an intake which wasn't what we wanted.

There was a video floating around somewhere on CD in like week 4 of a mecanum intake which worked, but wasn't as fast as we knew that it could be. That, the sheer simplicity of it, and 118 shipping with one made us switch over immediately after ship. We slapped together a prototype on our practice robot, worked out the ideal roller placement, and then built it. It took us a little bit over a week to pull the whole thing together from design to full implementation. It was during that time that we learned that a traction wheel in the middle would cause it to jam, but an omni wheel in the middle let it center nicely as the ball was coming into the robot. We figured that out by pulling dozens of balls into our prototype and high-speed videoing it while trying to jam it. Unfortunately, this meant that we needed a separate CDF/Portcullis mechanism, since our old intake could open them, which added more mechanisms and complexity.

I think it was very effective and we will consider doing something similar in the future. I liked our 2012 intake slightly more than this one, but I really can't complain. 2012 (which I saw a number of teams do variations of) would have required some crazy folding geometry for going under defenses. There were very few times when we contacted a ball but didn't grab it.
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