Re: Rookie Team 1746 creates it's first prototype robot
 

Looks great guys. and Kyle is definitely right, K.I.S.S. all the way. As for the problem of the bot veering to the left slightly, from what I can tell you have you axle mounts mounted directly to the 80-20. You may want to check that your 2 drive wheels are spaced exactly the same position on the chassis for both sides, if they aren't that may be what is causing your problem.

JT
229

Re: Rookie Team 1746 creates it's first prototype robot
 

Yes check on the spacing. When we used the 80/20 back in 2001 for our robot we had to check them every so often because they loved to slide on us. Also be careful with the 2 wheel drive robot, especially if you get into a pushing match with a team since yours could possible spin easier than one that is 4 wheel.

Also there I haven't searched through the White Papers on drive trains or other mechanisms lately so I'm not completely up to date on what they have. But i do know that if you are interested in researching drive trains there are a few helpful pieces that JVN wrote up on our teams website. One of them is here:

http://team229.org/resources/single/181

Good luck to you guys in the up coming season. Hope to see you guys doing well at the regional(s) you attend. Remember to K.I.S.S. and you guys will do fine.

Re: Rookie Team 1746 creates it's first prototype robot
 

Looks like you have a very good start Snappel!

Concerning the drive train, you may want to be aware of whether or not your drive train meets the demands of the game. What you have here is great for a game that requires maneuverability and good offense (such as this past years' game), but I would not recommend this setup (2 wheel drive with casters) for a game that was highly defensive and required your robot to push another robot or drive up an inclined surface (any veteran teams out there remember the "caster-bots" of 2003 and how they would often veer off to the side while trying to get up the ramp?)

The same principles that make 2 wheel drive robots extremely maneuverable are the same ones that make them easy to push around. If this coming year's game requires alot of defense (bots pushing other bots), I would not recommend going with this setup. Instead, I would go with a 4 wheel drive setup instead.

Perhaps you know this already, but by altering what is called the "track" and the "wheel base" of a four wheel drive robot, you can achieve different degrees of maneuverability. Here is a paint sketch illustrating this:



Perhaps the first time you tried building a 4 wheel drive, your track was too short in comparison to your wheel base. You can try adjusting the ratio of track to wheel base until you find a perfect balance between maneuverability and pushing ability. I would recommend this setup for dealing with inclined surfaces (such as ramps), as well as defensive ones, so that your robot won't have difficulty climbing them.

Of course, there are alternatives to this design. You could go with a six wheel drive robot, with its middle wheel slightly lower than the rest, which would give it both a high degree of maneuverability as well as pushing power. Or you could try omni wheels, swerve drive, mecanum wheels... etc. However, the 4 wheel drive design is the simplest available in comparison to the others... and as rookies, it is best for you to stick with simple designs that you can master before progressing to the next level of complexity in design. I believe someone has already said it, but I will say it again: K. I. S. S. (Keep It Simple Silly)! Oftentimes, the simplest ideas are the best ones.

Good luck,
-- Jaine

Re: Rookie Team 1746 creates it's first prototype robot
 

BurningQuestion has a lot of great information. The bottom line is that simple 4WD skid steering has to overcome the friction of the wheels to slide them sideways. Thinner wheels, omni wheels, shorter wheelbase vs track are all ways to reduce the effect of the wheels skiding sideways. Engineering is all about compromise and designing for the task that the competition presents.

Looks like you guys are of to a great start.

Re: Rookie Team 1746 creates it's first prototype robot
 

"Rookie" just means you are new to the game, not that your team isn't as skilled as many already in the competition.

Last years final rookie team in FRC, 1708 from McKeesport, PA, was a Regional Champion at Pittsburgh. You may be surprised at how well your team does this year, but most veterans won't. We've seen talented rookies come in every year and play at very high levels of competition.

Good luck, and enjoy your season!

Re: Rookie Team 1746 creates it's first prototype robot
 

This looks really good. Do you have last year's FRC Robot Controller on it?

P.S.
Always have safety glasses on when having a picture of you working with the robot.They almost disqualified a team in last year's Israeli regionals because of that.

Re: Rookie Team 1746 creates it's first prototype robot
 

Wonderful robot! Remember to design the robot specifically for its task in the competition. a 2-wheel drive is simple and reliable on flat ground, but helpless on a ramp, or even if something is stuck under it. Conversely, a four-wheel drive might work well on ramps, but can't turn to save its life. Make sure to keep a low center of gravity too, and ween yourselves off 80/20 as soon as someone can weld a chassis for you! Squared aluminum tubing is much lighter.

That, and creative programming can solve almost any problem.
That's my advice for you, good luck!

Re: Rookie Team 1746 creates it's first prototype robot
 

You said one month, at 2 days a week? Wow! I hope build season goes just as smoothly for you guys. I wouldn't be the least bit suprised if you guys made it to Atlanta. Good luck!

Re: Rookie Team 1746 creates it's first prototype robot
 

last year we used ACME casters
http://www.constantines.com/browsepr...e-Casters.HTML
they also make some with plastic insted of steel ball bearings - which is what we used because they'll a lot lighter. they handle super smooth