Chief Delphi - anti-gravity-gas

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Re: anti-gravity-gas

Quote:

Originally Posted by generalbrando

Also, get creative! Go on down to Home Depot or Lowes or Menards for you Midwesterners. Look around and see what they have for you to play with. You'll find strong aluminum tubes that are very light and relatively cheap.

We didn't use any this year, but I've found the best stiff lightweight structural material if you don't need the strength is 6 ft. shower curtain rod that Home Depot carries - it's 1 inch diameter by about .015 thick if I recall. Makes really nice long mechanisms - you don't get the droop of PVC.

Re: anti-gravity-gas

when you're done drilling holes in the air tanks, and you're still over, make sure you take that proton-heavy lead out of your battery.

Re: anti-gravity-gas

Quote:

Originally Posted by ToMMan b182

well our personal preference is hydrogen, but sometimes that can get rowdy.....

naa im just kidding. all you need to do is selct materials wisely. EX. if something that you are planning to make of 1/2 lexan can be made with 1/4 aluminum, go for the aluminum. (also see the reference on what is called a mill and thing that goes on mill to make big holes...hey im a programmer, what do you want?)

Take a vacuum pump and suck all the air out of your pneumatic system. No air is lighter than H2.

Re: anti-gravity-gas

Quote:

Originally Posted by Adams High Man

alright, what are all you people injecting into your air tanks to make your robots 130lb? we are bordering on 130lb, and we barely have anything! our arms are fiberglass, our transmissions weigh 2.5lb. Then i see all metal robots with 6 wheels, big huge gear boxes, and 10' long arms. whats the secret?

I often wonder the same thing. Besides the team secrets Andy leaked earlier in the thread, here are a few mostly obvious tips off ghe top of my head.

Not all aluminum frame materials are equal. Pick something that is light. This is an area that can make a big difference. Last year we made our bot out of 1.5 in welded aluminum square and we were overweight. This year our robot is at least 4 times more complex and was undereight. We used 1010 series 8020 extrusion. With square round, etc wall thickness is a big factor.

wheels suck weight There is no need for giamongous metal rimmed go-kart tires. Avoid anything with metal rims like the plague.

resist the hive As goofy as this may sound, wires do take up weight, several pounds of it. Avoid hivelike electrical panels, make things as short and neat as possible.

No need for overly beefy gears. I see alot of gears that look like they belong in a bus transmission. avoid gears with hubs. Use keyways, and spacer tubes. We have gearboxes that we direct drive out of with 12.5 in wheels that combine the chips and the drills. They use 8mm wide module 1 hubless steel metric gears and are plenty beefy. Don't be afraid of plastic gears and sprockets either. Timing belts can pften be lighter than chains.

swiss cheese it early you cna save alot of weight and frusteration if you lighten parts from the start. If there is any unnecessary, non-structural material on a part, remove it.

Stay away from oversized fasteners Fasteners take up alot of weight. Use ones that are the right size. IE: not too long not too wide. In some cases if you are really desperate, you ,ight consider going back and replacing things with plastic equivalants. IE: electrical components.

Re: anti-gravity-gas

Two words....Thinwall Aluminum.

Re: anti-gravity-gas

Quote:

Originally Posted by SwaDan

when you're done drilling holes in the air tanks, and you're still over, make sure you take that proton-heavy lead out of your battery.

Bah, just use the battery that came with the EDU-Bot to run your robot!!! That sucker is so small and light... Alot lighter than than that passe' big battery you get in the kit!!! That battery is like so 5 minutes ago!!!

Re: anti-gravity-gas

Remember. Your RC is heavy. More specifically, the chips inside your RC are heavy because they contain data, and data is heavy. Open up the RC and drill a hole through each chip. Also, pneumatic tubing weighs a lot. It too can take many, many holes.

In all seriousness, tho, a charged battery weighs a noticable bit more than an uncharged one. 13.5 and 10 lb, respectively, if I remember right... Dosn't make sense to me, tho... Electrons arn't that heavy. Hell, you don't even know where they are/are going.

Re: anti-gravity-gas

Well, if you're really having problems with weight you can do what Greg did for our robot. Drive it backwards off a platform over a foot high and put a hole in the side of our compressor. That worked wonders. *shakes head*
:D

Re: anti-gravity-gas

Helium? A vacuum? Why not just use a little engineering ;)

our robot weighs in at 84lbs http://www.chiefdelphi.com/forums/sh...ad.php?t=26186

Re: anti-gravity-gas

Quote:

Originally Posted by telkanuru

I'm curious, have you actually weighed the same battery charged vs uncharged? Did you get this information from a source (if so, could you point me towards it)?

I'm not doubting you :) , I'm just trying to figure out what might cause this. Keep in mind that a charged battery has the same number of electrons as a uncharged one.

It is possible to lose quite a bit of weight by drilling holes, removing excess wires, and eliminating redundant fasteners. However, if you need to lose any substantial weight you'll probably need to redesign or eliminate a major component. Look at everything on your robot and ask yourself the question "Does this part add any value to my robot?" If you answer "no", cut that part off. It’s really disappointing to have to cut a major (and working!) subsystem off a robot but its often the only way to make the weight limit.

Greg