Why is weight so important?

[AdamHeard]

I view weight as a limited resource on the robot, you can only have so much of it.

If you could buy drive gearboxes that worked great, were reliable, and fit your application perfectly for $100, why pay $200 for something that does the same thing? I feel the same way about weight, if you can cut weight WITHOUT killing reliability (which should be obvious, you should be making parts strong enough regardless), I see no reason not to.

Being lightweight in component design allows you many benefits; you can fit more on a robot as it all weighs less, you can keep the robot weight light for better driving & decreased battery use, and you can make up that weight with ballast real, real low on your robot to put the CG exactly where you want it.

I've seen a recent trend on CD that many people feel that removing weight through machining operations is unnecessary, and even a foolish waste of resources. It is a worthwhile operation, and doesn't even *need* to be a CNC'd accurate operation, much of the cosmetic pocketing you see on gearboxes with fancy curves and such can be approximate with a manual mill (if you know integrals, imagine you're approximating the pocket with a bunch of rectangles X units wide. X being an endmill small enough for a decent amount of material to be removed, but large enough as to not take forever). You can even draw the pattern you'd like, and drill or dremel material out; just don't take more material out than you designed in the drawing.

Before trying to machine weight out, assuming your fabrication resources are limited, you should consider thinner and lighter materials or just try to make parts smaller overall.

[Al Skierkiewicz]

As mentioned, weight is an issue with the new control system being about 3 times heavier than the old one. Generally speaking, teams have a hard time staying in the legal weight limit with a bare minimum running much less. Last year I had one or two teams that weighed in at less than 90 lbs. with the bumpers. I had one team weigh in at 143 lbs. due in part to a faulty scale at their shop. Note to self...test the scale using last year's robot with the battery out to be sure.

[MrForbes]

Weight is definitely very important. There are different ways of dealing with weight, though. If you start out with a realistic weight budget for different parts of the robot, and revise the design as needed to meet that budget, then you might be able to get away without having to do any "weight removal" machining at all. We did this last year, our robot was pretty big and capable and weighed 10 lbs under the limit.

There are some folks who seem to get carried away with making everything as light as possible, and they probably have a great future in the aerospace industry. Others don't really worry too much about spending any extra time making things light, and they probably have a great future in the consumer goods industry.