Weight Concerns

[Chris Fultz]

Some tips for managing weight:

Before you start anything, weight the parts that will absolutely be on your robot -

the controller, spikes, radio, etc.
Include some extra weight for wiring. Include the back-up battery.
Then add transmissions, drive motors and some drive gears and some chain.
Then add wheels or treads.
Add the pneumatic pump and mandatory controls (regulator, switch, etc.
At this ponit, you have the required basics covered.

Subtract all this from 120 pounds and this is the weight you really have to work with.

Assign maximum allowable weights to each remaining subsystem based on past history.

For example:

Frame 8 pounds -
Ball lifting mechanism with motors 12 pounds
Shooter mechanism with 2 motors 15 pounds
etc.
Make sure the estimates are realistic for your capabilities and materials.

It is important to know that you really don't have 120 pounds to work with.
A big percentage of that weight is already allocated to the mandatory robot materials.

[Andrew Y.]

yea, im a little worried about the weight of our robot.

Hmmm..im gonna haveta bring that up in tomorrows meeting...
haha...this is why i love chief delphi!

[65_Xero_Huskie]

lol, our chassy was over 100 lbs when we put it together, thats without the stuff to use balls.....so..yea..as u can guess...were gonna have to drill some holes....or something..but were not making swiss cheese, our chassey is sweet, if u can check it out, plz try, u will be impressed

[Madison]

Originally Posted by Chris Fultz

Some tips for managing weight:

Before you start anything, weight the parts that will absolutely be on your robot

Several years ago, Cyber Blue made a spreadsheet available that contained common robot parts and their weight and also allowed for the user to vary quantity and such. It's been very helpful, but is now a few years out of date. Do y'all still have anything similar?

[Kim Masi]

Our team saves (well at least tries to save) every ounce out of our robot while we can...a mentor and i were having fun weighing everything that goes on the robot...so far with the shooter and the drive system we're at about 30 lbs. however, we have always been overweight in years past so we've already swiss-cheesed our shooter...i love how i just used swiss-cheesed in a sentence....I've never used cheese as a verb anymore...hehe

[Cody Carey]

Hole-saws are over-rated... there is nothing like a home-made hacksaw to do the trick.

[Nuttyman54]

We always do a quick weight check before building (which always shows we have plenty of weight to work with) and by the end usually end up scraping the upper limits...no one's really figured out how that happens, but i have a hunch it has to do with the little fixes we make for problems that pop up along the way....

[MudThumper]

normaly during the design of the robot we like to keep our weight in check or at a close average, we have done this for several years and have been pretty close every year with in 5 lbs of the total weight. another thing that alot of people forget about when building is the center of gravity and where yalls weight is efects how easy it is to tip over.

[Schneidie]

Originally Posted by Nitroxextreme

Weight is on everyones mind throughout the build season...but how many teams try to keep it in check

Do you wait till the end than cut it out?

Today we found out that we just simply many not have the weight to do what we wanted so the first thing that we turned to was the hole saws

Now we are confident that we can do what we want as long as we drill everything out (with proportion and structure in mind)

So far, this year we haven't weighed our bot, but we have lightened parts to keep weight in mind.

[paulcd2000]

we're a new team, and so far I don't think anyone has realized that there is a significant weight limit. We're probably going to turn our bot into swiss cheese at the end.

[chinckley]

We are hoping to take ours to the local vet to have it weighed tomorrow.
We have the basic chasis without hopper, shooter, etc on it.

They we can weigh the big additions. Last year we were just over and we made a few plugs and then we were 4 ounces under.

Carolyn

[KTorak]

As of now, we are 90% complete and around 30-35 pounds UNDER weight.

We'll typically get the chasis built and working (wired), then weigh the robot, then we'll build the main component(s), weigh the robot, then go from there. If we're under...awesome, if we're over....we'll go machine holes in some non essential bars of our chasis.

[chinckley]

How much are the bumpers weighing? Are they coming out at the 15 pound limit (3 oz per inch) or are they weighing more or less?

We are just starting ours.

Carolyn

[KTorak]

Originally Posted by chinckley

How much are the bumpers weighing? Are they coming out at the 15 pound limit (3 oz per inch) or are they weighing more or less?

We are just starting ours.

Carolyn

There is a seperate 15lbs alloted to the bumpers + all fastners for the bumpers as per <R35>. http://www2.usfirst.org/2006comp/Man...obot_Rev_D.pdf , Page 11. We've yet to even really discuss/decide if we are going to build them or not. Odds are we will...we still have 15 days left.

[jpyro]

Make it work at a reasonable weight, then start thinking about what to cut. Mark what is not used, calculate weight in square in, then cut. Do this last after you spend forever measuring and calculating.