Will your robot fit in the box?

It’s three days into the 2008 season, and it’s very likely that most teams are still deciding what to build. That means that it’s a very good time to remind everyone about the fact that each robot will be placed inside of a sizing box, as part of the inspection at every event. (See <R11> and <R108>.)

Your robot must fit in the box.

Your robot may not cross the boundaries of the box, even by 1/16 of an inch. Even zip-ties, bolt heads and decorations count toward this restriction!

Your robot may not push on the panels of the box, or use it for support (except, obviously, the floor). Many robots violate this rule every year, and many inspections are failed because of it.

It’s a fact of the competition that robot frames sometimes bend, or parallelogram. This can cause the bounding box of your robot to grow, potentially in excess of the size limit. Design your frame so this doesn’t happen, perhaps by gusseting the corners, and using the bumpers as structural elements.

Remember, the sizing boxes measure every dimension at once, while a tape measure only measures lengths, not angles (which aren’t always 90°). Plan ahead now. If there’s no functional difference between 37 in and 38 in, why not leave yourself the extra space? The same goes for the other dimensions.

Don’t be the team that ties up an inspector and a sizing box for 30 minutes, trying bravely to slide their robot in “just right”. Even worse, don’t be the team that whips out the hacksaw at the competition, because they didn’t plan ahead.

P.S. Remember to weigh your robot well before the ship date. A regular bathroom scale usually works for this purpose. You don’t want to be 30 lbs overweight on Thursday evening, 15 minutes before the pits close. (This really happened, but I conveniently forget which team was responsible.)

The other box you have to fit into is your shipping crate. Not as much an issue as last year when you could have a 72" robot. But you still have to fit 60" of robot into a 70" (outside dimension) crate, with forklift skids.

Mmmmm. Sizing box. It’s so true what’s been said about the unforgiving box. I will (sadly) say that we had to (slightly) modify the robot thanks to the sizing box. But teams, I can tell you now! While SOMETIMES an inspector may be nice enough to let a ziptie head that pokes out 1/16th of an inch over the 38 inch limit slide, don’t let it happen. Play it safe, and leave a 1/2" safety zone on all sides of the robot to account for any parts that stick out.

You could do what we do – Max dimensions are 36" x 26". That’s an extra 2in for each dimension. For bolt heads, zip ties and so forth. Worked well last year, too. Even when our frame was warped. And we never needed to use a hacksaw.

I’ve always allowed 1 inch off of each dimension. It’s come in handy quite often, for when you suddenly decide you have to bolt some new componend onto the outside of the robot.

Another recommendation: if you’re building an arm or any kind of mechanism that folds up, make sure you have enough clearance for the pieces to fold into starting position. I misjudged one section on last year’s tube gripper (a pneumatic fitting!), and suffered in every inspection because of it. I couldn’t make any modifications without destroying other parts, so we were one of those teams trying to get the robot to fit “just right”. It’s no fun, trust me. 2006, with our 27"x37"x59" box, was much less stressful, by far.