Help out rookie/less experienced teams

[AdamHeard]

Originally Posted by Otaku

That all being said, I've seen bots with KOP wheels have a harder time turning than IFI Traction V2 wheeled robots.

Just want to reiterate.

The Kit wheels have a lower coefficient of friction than the IFI traction wheels. Any robot that has trouble turning with KOP wheels, would have more trouble with the IFI wheels.

The way to improve turning is in the drivetrain design (lowering the center wheel on a 6 wheel drive, etc...).

In general, it is best to use the maximum possible coefficient of friction for the wheels (I'm going to get some flack for that). Sure, high coefficient of friction wheels will make it harder to turn (compensate for that in design....) but will increase the robots traction.

I would reccomend checking out the following teams drives (in no specific order); 1345, 217, 1114, 254/968, 330, 233, 45, 190, 234, 179, 1889, 177, 121 (excellent example of KOP frame use), 116, 1717, 125 and a whole bunch more... All are good examples of 6 wheel drives (of varying complexity), which I believe to be the most resource effective drive for most FIRST applications.

Shameless plug, but 294's drive is pretty good this year.

[Otaku]

Hmm.

Well, when I get some free time (probably after Nationals), I'll whip out some (very) basic 6 wheel chassis designs involving both omniwheels and rocker chassis (but not at the same time), and perhaps a few more 4 wheel Chassis designs (or rather, more detailed ones)

Also, any and all Diagrams that I have/will make are yours to manipulate, use, or otherwise take in any fashion, as long as you don't claim them as yours. I do not require that you say that I made them, however. Just say "I got them from a buddy" or "I got them from somebody on CD" or something to that effect.

[Otaku]

Alright, well, I can't edit my original post, So I'll have to update it some other way.

Here's a new diagram I made. It's mostly self explanatory.

[wilsonmw04]

we used the KOP chassis and the 6-wheel drive(middle lowered and the KOP wheels) during our rookie year. It worked VERY well for us. We used the banebot tranny with a supporting bearing at the end of the shaft. We had zero problems with it. Turning was easy (sometimes too easy). That's something i'm having the programmers work on this summer.

Here are a few pics of the drive train before it was finished. It's rough, but you get the general idea. If you want to see it in action, check out the VCU match #50 on SOAP. We did well until be broke the arm

http://www.chiefdelphi.com/media/img...426e384c_l.jpg

http://www.chiefdelphi.com/media/img...d32e6bc4_l.jpg

[Otaku]

Hmm. KOP Wheels + Rocker Chassis... not something I had thought of before.

Kudos to you and your team for coming up with that.

I'm thinking I might just go ahead and find some graph paper and draw up the other diagrams then scan them -- it'd probably be less legible that way (photoshop could fix that) but more precise.

[MrForbes]

Originally Posted by Otaku

Hmm. KOP Wheels + Rocker Chassis... not something I had thought of before.

Kudos to you and your team for coming up with that.

that's what comes in the kit....although you need to get two more wheels...so it's not something secret

[Otaku]

Originally Posted by squirrel

that's what comes in the kit....although you need to get two more wheels...so it's not something secret

Remember, I've stated that I've not built a KOP Chassis before. '05 was 675's last year of doing so (for Triple Play). For both Aim High '06 and this year, we've taken aluminium stock (3x0.25 in) and turned it into a chassis.

[MrForbes]

We used fiberglass for the 1726 chassis last year and this year. But we did spend some time looking at the kit chassis, and noticed the lowered center holes.

The fiberglass works very well as a chassis material...it's tough, easy to work with if you don't have a machine shop, and the shapes we use work well for robots. The side rails which hold the wheels are I beams turned on their side, the ends are channel, and it's all held together with bolted on aluminum angles (similar to those you've shown above). We learned about this material from our mentor team 842. We use a different frame layout than they do, though.

[T3_1565]

wow what a thread to find! Being on a less experienced team myself and being one of the few that wish to prototype sweet design, we have decided to try a crab drive (to keep up with you vetren-like). I don't mean to be rude or anything and I understand this is a thread to posted ideas, not ask questions but is there any chance someone could ethier post or PM me on the simpliest way to start a crab drive. And before you ask I do understand it is complicated to do, thats why I am starting now

[Otaku]

Feel free to ask them to post it here!

This isn't just a thread for more experienced teams to help out less experienced ones, but a place where less experienced teams can come to ask for help. Remember, we're all gracious professionals here.


That being said, I don't know anything about Crab or Swerve drive. Sorry.

EDIT:

Oh, but I did find this article on Wiki Books...

http://en.wikibooks.org/wiki/Robotic...hysical_Design


Enjoy. =]

[T3_1565]

Originally Posted by Otaku

Oh, but I did find this article on Wiki Books...

http://en.wikibooks.org/wiki/Robotic...hysical_Design


Enjoy. =]

Thanks for that! I have done some research on crab drives and thats why I want to make one! unfortnatly I'm not sure how to go about starting said crab drive so any team who has done a crab drive before, it would be great to know how you started lol!

[AdamHeard]

Originally Posted by T3_1565

Thanks for that! I have done some research on crab drives and thats why I want to make one! unfortnatly I'm not sure how to go about starting said crab drive so any team who has done a crab drive before, it would be great to know how you started lol!

71, 111, 114, 118, 16, 469 and 1625 have all done crabs.

71, 111, and 118 have been doing them for years, so I would talk to them.

[Otaku]

Originally Posted by squirrel

We used fiberglass for the 1726 chassis last year and this year. But we did spend some time looking at the kit chassis, and noticed the lowered center holes.

The fiberglass works very well as a chassis material...it's tough, easy to work with if you don't have a machine shop, and the shapes we use work well for robots. The side rails which hold the wheels are I beams turned on their side, the ends are channel, and it's all held together with bolted on aluminum angles (similar to those you've shown above). We learned about this material from our mentor team 842. We use a different frame layout than they do, though.

...Woah. Fiberglass?

I'll have to mess around with that after I get a job. I'd love to see it's potential.

[Smaug]

baker post our design that you were given today it is a exact size to our bot. one of our teams drew it so each of our groups can have a copy. it is a extremely simple design. through out the comp. we were at there were quite a bit of teams who like our drive train and chassis cause it was so simple and it is an awesome test plat form.

[Otaku]

I've yet to get around to putting it into Sketchup or anything. Blake left some dimensions missing (no big deal, it's a 1:1 blueprint after all), so I'll find my tape measure then mark those in.

That, and I'm not used to CADding things, so chill out a little bit. It'll get done. Maybe not today, but it will.