I was just wondering how much a typical VRC robot weighs.
Last year, the one tournament our team competed at was mainly composed of rookie teams, and our robot was one of the heavier ones at 12.5 pounds.
How heavy are typical VRC robots?
11 to 22 LBS is a good range. I’ve seen some beasts in prior years but last years robots traded weight for speed. This year the hanger-bots should be pretty light, I’m guessing 10-15 lbs.
Our robot last year for Clean Sweep was all-steel, (Until late in the year when we bought a kit of aluminum and used a few parts of it.) and when it was all-steel it weighed about 16 pounds I believe. This year we are using nearly all-aluminum, but have not yet weighed our robot. I hope to do this soon so we can do hanging calculations to see if it’s possible with our robot.
~Jordan
Typically, I’ll end up with a robot that weighs about 12-16 pounds. The target weight I like to shoot for is 8 or 9 pounds, since with less weight you can gear your drivetrain faster, but unless a design is absurdly simple I usually ended up at 12 pounds somehow.
I am currently at about 18 pounds. And that is with virtually all aluminum (though my use of pneumatics and batteries is fairly liberal). I will be competing next month near Pittsburgh PA and I expect that I will be the heaviest high hanger there.
The weight of the robot does not effect it immensely but I do plan on lightening it up later in the season.
It depends on the game.
- If there is something on the field to drag around (eg: QQ goal post, FRC Lunacy trailer), then heavier has some advantages.
- If you have to hang your robot (eg Hanging around, Roundup High Hang), then lighter has some advantages.
Low CG is almost always better than high CG.
Dallas BEST Game day last Saturday showed that simpler can be better;
A middle school team with a relatively simple dumptruck robot with small wheels was near the top, because they had enough time to practice driving, and didn’t have to do any precise grab movements with an Arm.
Heavy robots win pushing matches versus light robots, all other things equal. Quad Quandry was kind of the exception to the “lighter is better” rule. In that game, a majority of the points were determined by where mobile goals were located. A heavier robot could push a lighter robot controlling a goal out of position. Heavier robots also require more force to be moved.
Quad Quandry pushing matches got intense - in my event, robots pulled against a goal with enough force to unbond PVC adhesive and tear two goals apart. It was a game that seemed to call for two distinct types of robots: nimble scorers and goal controlling tanks, and inept teams that attempted to do both at the same time didn’t do so well.
This year, it seems both offensive components of the game emphasize a light robot, and that the standard defensive route of blocking the primary scoring objective and making up for the deficit with the end game will be a lot harder. This is mainly why I think defensive strategy this year won’t center around pushing, if it is a gameplay component at all, and that teams should focus on the offensive aspects of the game.
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Three Exothermic robots for “Elevation” were under 8 pounds. Last year, most were 10-11 pounds. I believe that the average robot at worlds in 2010 was probably 12-15 pounds. Some have been well above 20, but they were beasts.
What I’m waiting to see this year is whether everyone is building 18" cube “Maxbots” or if we will see a return to smaller sizes and greater agility.
our robot is 17 3/4 on all three dimensions!
but know where near the weight 
i think ours (round up) should be around 10-12 pounds
we didnt weight it yet
Previous Twisted Botz Robots (FVC,FTC,VRC) have generally weighed over 20 lbs. We didn’t consider them beasts or inefficient. Yes they did push the envelop on what the batteries and motors could do. They were designed to do as many tasks as possible as well as possible. Last year’s robot had about 5 lbs of counterweight! We use lots of aluminum to keep them that light!
This years is currently much lighter but we haven’t added the pneumatics yet.
A more generalized rule is “make sure your center of mass is evenly balanced across your drive wheels.” We’ve had both VEX and FRC robots that have been weighted to one side and have provoked driver comments of “It won’t turn to the right!”
The best first to follow is “Make sure your drive train is square and plumb and that all the wheels touch the ground”. A warped frame creates a huge set of problems down the line. In lots of cases moving the mass around isn’t going to help a frame/wheels that does not sit flat on the tiles.
No problem, by using CoM it means the formulas work out when you guys get that holonomoic hover unit working :rolleyes:
Well, now that the surprise is gone, back to the drawing board…
Sorry, I was just trying to give you a running start on the Inspire Award. But since you figured out that you can sand the top of the LED lights into a lens and use the focused beam as a Laser Range Finder to lock into the top of the goals you were still unbeatable.
Oh wait …:eek:
Our past robots:
~9lbs: Elevation
14 lbs: Clean Sweep for first 2 competitions
12 lbs: Clean Sweep worlds.
I’ve tormented the Vex community with a secret subconscious unachievable challenge haven’t I?
So much FUN! 
-Cody
EDIT: Right, the reason I wrote this post. Piratech has had a 12 lb robot, all the way up to a 28 lb robot. YES, 28 pounds! That thing was a beast with six motors powering it’s base (V6 for the win). I would say that 12-15 is great, 15+ is getting heavy, 12 and below is lightweight (which is usually good).
last year our robot was 6 1/2 lbs and was extremely fast. The problem we encountered was that it was flipped constantly. So tip,(literally) make your robot at least 11 pounds. If people try to push that and you push them back it can burn out their motors, so they stop pushing you.
Tipping is a problem with center of gravity, not with the robot’s weight.
Our robots have always been more than twelve pounds. Our final robot for worlds this year was 17 lb with everything stuffed in the chassis for a very low COG. Typically the heavier robot will win in a pushing contest. That of course though is also based on how the drive train is geared.
the heavier you get, the slower your drive also have to be (if you dont want any tripped breakers/motors)