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Unread 09-01-2008, 11:25
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Cjmovie Cjmovie is offline
1293 Resident Hacker
AKA: Christopher Corsi
FRC #1293 (D5 Robotics)
Team Role: Programmer
 
Join Date: Jan 2006
Rookie Year: 2006
Location: SC
Posts: 73
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Re: pic: Omni Design Trial

We do have access to a water jet, luckily. Classically all the designs coming from our team have consisted of large amounts of sheet metal. Which is pretty cool, because although it makes them all a bit homogeneous, they give a certain "1293" style to our robots with the artwork we cut into them.

Mostly what I'm worried about with this design is whether the motor mountings are strong enough. Like I said, this is the first full design I've done myself (Actually, first design I've really ever done except changing someone else's) and I'm not an engineer... I'm actually the team programmer.

My point in having Omni's vs. Mecanum is twofold. First, the one my team will probably be most happy with, is that they're a bit cheaper, and it makes every single motor assembly interchangeable for repair/replacement. But from a design standpoint, it's because it then becomes just as easy to herd a ball on the long end (therefore less change of it shifting left/right outside of the robot's pushing front) as it is to drive around robots on the short end.

As for the gearboxes, those will most likely be the same ones Banebot supplied from last year (We had ordered a couple extra, but they didn't arrive until after the season, so we can play around with those... We're thinking about doing what we did in 2006 and building a duplicate to keep at the shop).

The main idea behind this design was to make the entire thing modular. Any part can be removed from the base without more than, worst case, 6 bolts. And those on opposite sides of the robot are interchangeable, so if something gets bent up, we only need one extra for 4 shapes and we'll have a spare for anything we'll need.

Also, any idea on whether the strength of UHMW is up to the challenge of a full chassis? I'd rather not have a $2K piece of UHMW turn into two cracked-in-half robots. (Which is partially why I added some of the extra sheet metal, for reinforcement).

As for the current weigh in, it's at 40 pounds based on Inventor. But I believe the estimate of weight in Inventor for the motors is a bit low (I think it says 2 pounds), so it's probably much more realistically around 65 including bolts and bearings. I'll also need to add in the gearboxes, so my best guess is that it will end up around 85 pounds. Forty pounds should be plenty for the electronics and arm, I think. Although we do have a nasty habit of always weighing in at 120.1 pounds.... or worse. (I think one year we dropped 8 pounds by cheese-holing everything possible for our robot, with a quite humorous effect on its looks).

Thanks!
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D5 Robotics, Team 1293: Programmer, CAD'er, Mechanical, Electrical... I've made my rounds.
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Last edited by Cjmovie : 09-01-2008 at 11:28. Reason: Add weight at end...
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