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Re: Building large wheels

Posted: 07 Dec 2011, 13:19
by stryker001
sparramc wrote:The attached LEGO Digital Designer CAD File may be of assistance to you with your Rover design.
ExoForceRover.zip
I really like the design you had on your blog, so I bought 4 green wheels and I'm trying to get a hold of a second turntable (there are non on BrickLink at the moment).

Ironically, this sorta defeats me learning how to make big wheels, but now I have some and I shouldn't have to worry about needing more for awhile. :D

I don't have LDD, but I'm gonna be getting LDraw on my new computer. Is there a LDD viewer, or do I have to get LDD as well?

Re: Building large wheels

Posted: 07 Dec 2011, 14:12
by hassenplug
I think there are a couple options for mounding those wheels.

1) Use a very sturdy attachment like sparramc posted
2) Support the outside of the axle, like JBrost did on his voyager:
http://us.mindstorms.lego.com/en-us/Com ... 291610c18b

3) Simply connect using an axle and some 1/2 wide pulley wheels.

The good side of option 3 is that it's simple. The down side is that the axles will bend, if there is too much weight on the axle. The other two options should avoid that.

Steve

Re: Building large wheels

Posted: 07 Dec 2011, 14:20
by stryker001
hassenplug wrote:I think there are a couple options for mounding those wheels.

1) Use a very sturdy attachment like sparramc posted
2) Support the outside of the axle, like JBrost did on his voyager:
http://us.mindstorms.lego.com/en-us/Com ... 291610c18b

3) Simply connect using an axle and some 1/2 wide pulley wheels.

The good side of option 3 is that it's simple. The down side is that the axles will bend, if there is too much weight on the axle. The other two options should avoid that.

Steve
:o The master himself!

Unfortunately, this will be taking some serious weight, or else I would just use option #3. Since it's a balancing bot, the wheels are in the center of gravity, and so all the weight is put on them... If I weren't doing a balancing bot, then I could shift a lot of weight off the wheels and feel safe about using #3. :)

For now, though, I'll try out sparramc's design and see what I can do.

P.S. Steve, JBrost mentioned something about your "Green Monster." What's he talking about? The link doesn't work. :|
JBrost wrote:I was both inspired and challenged by Steve Hassenplug and his Green Monster creation (http://mindstorms.lego.com/nxtlog/Proje ... e34b98c4aa) to build a self-navigating outdoor robot of my own.

Re: Building large wheels

Posted: 07 Dec 2011, 15:05
by sparramc
stryker001 wrote:I don't have LDD, but I'm gonna be getting LDraw on my new computer. Is there a LDD viewer, or do I have to get LDD as well?
You will need to download LEGO Digital Designer (LDD ) as LDraw won't import it.

LDD does have a LDraw export facility, but a lot of the Technic parts are missed completely or badly miss-orientated. As an example, the Technic Type 2 Turntable can be anywhere in your model. The Import facility is pretty good in comparison.
ExoForceRover.lxf
LEGO Digital Designer CAD File: ExoForceRover.lxf
(108.68 KiB) Downloaded 378 times
ExoForceRover.ldr
LDraw CAD File: ExoForceRover.ldr
(133.44 KiB) Downloaded 389 times
I find LDD easier to use than the LDraw Interfaces, but the Export issues are a real inconvenience though!

Re: Building large wheels

Posted: 07 Dec 2011, 15:20
by stryker001
sparramc wrote:
stryker001 wrote:I don't have LDD, but I'm gonna be getting LDraw on my new computer. Is there a LDD viewer, or do I have to get LDD as well?
You will need to download LEGO Digital Designer (LDD ) as LDraw won't import it.

LDD does have a LDraw export facility, but a lot of the Technic parts are missed completely or badly miss-orientated. As an example, the Technic Type 2 Turntable can be anywhere in your model. The Import facility is pretty good in comparison.
ExoForceRover.lxf
ExoForceRover.ldr
I find LDD easier to use than the LDraw Interfaces, but the Export issues are a real inconvenience though!
I'll try out LDD then. I have no idea how to use it :P

Re: Building large wheels

Posted: 07 Dec 2011, 20:41
by hassenplug
Here's my Green Monster:http://www.teamhassenplug.org/robots/GreenMonster/

It shows other examples of the wheels. I would most likely do what John did, and put supports on both sides of the wheels.

Steve

Re: Building large wheels

Posted: 07 Dec 2011, 20:56
by stryker001
hassenplug wrote:Here's my Green Monster:http://www.teamhassenplug.org/robots/GreenMonster/
It shows other examples of the wheels. . . .
Steve
Those are amazing. Simply amazing.

And, my Gyro just came in the mail like 5 minutes ago. <3 So happy.

Re: Building large wheels

Posted: 07 Dec 2011, 21:54
by mattallen37
stryker001 wrote:...And, my Gyro just came in the mail like 5 minutes ago. <3 So happy.
Would it by any chance be the dIMU?

Re: Building large wheels

Posted: 07 Dec 2011, 22:01
by stryker001
mattallen37 wrote:Would it by any chance be the dIMU?
tevye wrote:If I were a rich man, Ya ha deedle deedle, bubba bubba deedle deedle dum.
All day long I'd buy fancy IMUs, If I were a wealthy man. . . .
I so wish it was. It's just the cheap gyro from HT.

Re: Building large wheels

Posted: 10 Dec 2011, 05:38
by nxtreme
stryker001 wrote:Hey, I'm working on a new LEGO project and am in need of some nice big wheels (at least the size of CDs, if not a few inches larger.
Well, I have just the thing for you! I put these together almost a year ago but haven't done much with them since. I'm sure you have plenty of scratched or useless software CDs lying around, that's what I used. I botched up the notches on the inside edge of the CDs, but they still fit pretty well. I put some hot-glue on the edge of the discs for a bit of extra grip. Keep in mind, these aren't the best wheels, just the cheapest.

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