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Unread 14-01-2014, 01:01
bEdhEd's Avatar
bEdhEd bEdhEd is offline
Design and Drive Team Mentor
AKA: Frank E.G. Shiner
FRC #0701 (The RoboVikes)
Team Role: Mentor
 
Join Date: Nov 2012
Rookie Year: 2009
Location: Fairfield, CA USA
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Re: Forwards and Backwards Ball Pickup

Quote:
Originally Posted by atucker4072 View Post
Having a way to pick up from both sides does have its advantages. I see what you are going for now. You are going to want a good balance between torque and speed in my opinion. Or you can keep your loader light enough so that you can have a reasonable amount of speed. I don't think it would be a good idea to have a way to pick up from both sides but have it take a while for it to get to each side. That's why I said why no just turn.
We have a tried and true system for having speed AND torque without compromising either. We call it the "battle axes" because they are arcs whose center points are on the axis of rotation, and have chain along the arc length, with a sprocket rotating on a motor mounted on the arm. It's basically a rack and pinion system, but curved. We put this on our 2013 robot last year since we had a long arm that not only held all four disks in a line, but also had two 6" AM performane wheels at the very end for shooting. This is a pic of what they look like.


http://www.chiefdelphi.com/media/img...16ffd890_l.jpg

The diameter is about a foot, so it's like being able to drive the arm with a 12" sprocket , and only using 2 FP motors.


We intend on using this type of system again this year for a full rotation. Our heavy arm last year took about a second to get from down to top position, and we plan on having the same success with it this year. Turning around and rotating the arm should both take about the same amount of time.

The big advantage I forgot to mention is that during autonomous mode, we will be able to grab balls from behind us without turning, in the likely event that a robot has an unreliable, ineffective, or no autonomous mode. Just have the ball touch the other robot, and have the ball right behind our robot, and have programs for one two, or all three ball autonomous modes. If an alliance member is a goalie, they can place the ball behind us when it's in between the truss and the zone line, and we will never have to remove a ball from the beginning of the match.

My team would not prefer to turn around during auto, but rather go forwards and back, and reduce the chance of bumping into an alliance partner during auto if anything goes wrong during this period of the match.
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Last edited by bEdhEd : 14-01-2014 at 07:48.
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