View Single Post
  #251   Spotlight this post!  
Unread 14-04-2011, 14:12
Mark Sheridan's Avatar
Mark Sheridan Mark Sheridan is offline
Head Mentor
FRC #3476 (Code Orange)
Team Role: Mentor
 
Join Date: Mar 2010
Rookie Year: 2002
Location: Irvine, CA
Posts: 561
Mark Sheridan has a reputation beyond reputeMark Sheridan has a reputation beyond reputeMark Sheridan has a reputation beyond reputeMark Sheridan has a reputation beyond reputeMark Sheridan has a reputation beyond reputeMark Sheridan has a reputation beyond reputeMark Sheridan has a reputation beyond reputeMark Sheridan has a reputation beyond reputeMark Sheridan has a reputation beyond reputeMark Sheridan has a reputation beyond reputeMark Sheridan has a reputation beyond repute
Re: Minibot climb rate

Quote:
Originally Posted by AlDee View Post
At the beginning of the build season, someone had suggested magnets and we quickly dismissed the idea, thinking with the potential weights involved, magnets would not be practical, except perhaps to hold a latching mechanism closed. As the build season progressed we experimented with many differnt concepts and prototypes. I favored a balanced approach as you describe. I found that anytime we would get close, one tweak would throw the whole thing off. When someone put together a prototype with a rare earth magnet, it became very simple. No muss no fuss, just get it to the pole and climb. That was the direction we went and it worked very well.
Yeah my team was in the same boat as you. I honestly thought magnets would not work. Now my students are amused that mentors can be wrong too.

Bill,
I fixed the calculations on my end, I am getting a climb rate of about 1.10 seconds. So I think slipping is defiantly slowing you down.

I have also been comparing my minibot to the the polycarbonate one here:
http://www.chiefdelphi.com/forums/sh...&postcount=191

Ours is the same mass but defiantly slower. I think another variable to consider is the accuracy of shaft placement. Ours is defiantly poor, the shafts are not perfectly perpendicular to the pole, so we are defiantly loosing efficiency. I don't know if this is common for others, but when we attach our un-powered minibot to the pole, it won't roll down unless we move it a bit. An accurate minibot should just slide down when not powered. Ours still slides down after the climb because it bounces off the top plate.