Why is weight so important?

[JesseK]

Originally Posted by CraigHickman

For me, I design all moving parts to be as light as possible, and all fixed parts to try and hit the sweet spot between strength and weight. Lighter moving parts = less force required to get them moving = faster acceleration. Speed = win.

I fully concur! If anyone ever calculated their final power consumption under load (sans pushing and shoving), they'd probably find that 5 lbs of weight can easily translate into several extra watts of available instantaneous power. We all know what more power does: a more responsive drive train, faster manipulator movement, and more room for error when you're lifting a game piece.

For those of us who do offseason design, mainly drive trains are what you see. If we can shave 20% of the weight from a 35-45 drive train concept, we inherently add watts of power to be used in acceleration of the drive train. Another benefit of extra power is that drivers can simultaneously move more things at once, such as the drive train, and say 2 degrees of freedom on your manipulator.

[daltore]

Weight isn't to be blindly removed as a trophy piece, it should be carefully considered as to what it would affect. Sure, having a light-weight robot is very good most of the time, but under specific circumstances, it can be iffy. Last year, our robot weighed in at 99.1 pounds (without battery and bumpers). However, this was a 13-foot max height forklift, and it's center of gravity was actually fairly high with the lift lowered. In a practice match, 118 ran into us when we were putting the ball on the overpass and we went down, and on competition day in our second match, 118 just barely pulled us over when they got hooked on our arm early in the match. Then we added 4 steel bars about an inch from the ground and ended up at 119.1, dead on 20 pounds. Now they'd probably be the ones flopped over.

Weight is a structural property, and just like any other structural property, it can be used to help or hurt the robot.

But also consider if we'd had exactly 21 pounds of bars. To put that in perspective, that's a medium Red Bull away from being disqualified until another 20 minutes of work could be done, by which time we could have completely missed a match. Doing careful consideration on the generalized weight and weight distribution of your robot can really save you sometimes.

[Al Skierkiewicz]

Originally Posted by daltore

Then we added 4 steel bars about an inch from the ground and ended up at 119.1, dead on 20 pounds.

Note to all rookies:
Teams never give up trying and find all kinds of ways to improvise. However, unstated here is the need to reinspect before continuing with competition. Please involve your inspectors when making changes in the heat of competition. They can save you a lot of work and heartache.