Weighing the Robot

[rachal]

Originally Posted by Gertlex

I have, and solidworks refuses to tell me the mass of multiple parts in an assembly at once.

And I don't put the bolts in my assemblies.

Ah, sorry, I use Inventor. Our mentor claims Solidworks can do that, but I've never used it, sorry...

For physical measurements, we use a bathroom scale and a force plate that's part of our mentor(physics teacher)'s classroom materials.

[beemgruem]

I don't know if it does work, but I saw my host father that hug the doggy and scale and just minus his weight..

If it is not that heavy maybe you can try this too. My team did it but I don't remember how they did it.. I will learn it for you tomorrow..

[dlavery]

If medical or athletic scales are not available, there is one simple method that we have used in the past. Take your robot down to the nearest parcel shipping store (FedEx, MailBoxes Etc., UPS Store, and others). Tell them what you are doing, and ask if they will weigh your robot on their shipping scales. It is so different from what they usually are asked to do, that most of them are more than glad to help.

-dave




.

[Otaku]

Originally Posted by dlavery

If medical or athletic scales are not available, there is one simple method that we have used in the past. Take your robot down to the nearest parcel shipping store (FedEx, MailBoxes Etc., UPS Store, and others). Tell them what you are doing, and ask if they will weigh your robot on their shipping scales. It is so different from what they usually are asked to do, that most of them are more than glad to help.

-dave




.

I might just convince my team to do this for the hell of it. Not to mention the publicity.

[artdutra04]

Team 228 has two scales for weighing robots/parts, a 150-lb scale and a 400-lb scale. Here's a link to the 400-lb scale (which is the one we primarily use) that we have, which Staples sells for $150.

http://www.staples.com/webapp/wcs/st...plesZipCodeAdd


Like the previous posters, we just add on two cross members of aluminum and re-zero the scale, then weigh the robot.

[Sunshine]

We do a combination of ideas already mentioned. We keep track of individual weights right from the start as we check the kit of parts. The wrestlers have an awesome digital scale that they let us use.

Last year our robot weighed 119.6 pounds when we loaded it into the crate. And it weighed 119.8 pounds when it was checked at competition.

Moral of the story..... leave room for error.

[rfolea]

Hi Guys,

Need an inexpensive scale? Try this for $49:
http://www.northerntool.com/webapp/w...7409_200307409

It only goes to 110lbs, but that should probably be a good goal anyway ...

They have scales that do more weight - search on "Hanging Scales"

[Tom Bishop]

We just use a bathroom scale and tip the robot up on one edge, balancing it with one finger, While this is admittedly kind of dicey, it is accurate enough so that we have a good idea whether we are legal or not. When we have gone to a scrimmage or regionals for an official weigh in, we generally aren't to far off the mark, and we haven't had to shell out $$$ for a pricey scale, or drive to a different location to get an estimate of weight. Quick and cost effective.

[Chaos204]

I have a theory for weight management for the robot. In the shop the robot usually weighs in OK, the problem is when we unpack it is mysteriously over weight! I think the robot does some eating while at drayage or on its FedEx trip. Influenced by our heavy pizza eating during build the robot makes poor dietary choices causing it to gain unwanted weight. This year i will weigh the robot on the scale in the trainer's office. I think the robot will get jealous of the featherweight wrestlers and will suck it in as to not be over weight. To aid in the shipping process I plan on hanging a poster of the new food pyramid and hope for the best!

Best of luck everybody and think thin!

-Jordan

[wilmo]

scales in the school cafeteria

[Compnerd]

Last year we were 0.8 pounds under the maximum weight. We calculated just by parts.. We took alot of weight off just to be safe.

[AndyB]

Wrestling Scales and Shipping Scales here at the university.

[sethw]

We use two identical bathroom scales, putting one under each end of the robot. Add the two readings and we have the weight of the robot. It's not perfectly accurate, but usually close enough for us.

[lukevanoort]

In 2006 we used four old bathroom scales (one in each corner) and we were off by about 20lbs (thought we were ~5lbs under, and really were 15lbs over). Last year, we used a large scale a parent had, stuck a sheet of plywood on it, zeroed it, and then placed our robot on it. We thought we were tenish under and really were five under. I think part of the issue in 2006 was that we used freshmen to zero our scales (I'm not kidding, we had freshmen who new their current weights very accurately [from sports] and used them to zero our scales), and since the human body fluctuates so much (as any wrestler can tell you), our zeros were all kind of iffy.

[Blue_Mist]

Yes, Team 766 puts a board on a scale, zeros and loads on the robot. Also, if you weld the robot, remember the extra metal. We were able to gain space and lose quite a bit of weight just by angle grinding down our aluminum welds.