The rule says that we can not have alignment devices external to the robot, so if we Velcro two 2x4s to the robot would this be legal.
then the 2x4s have to be part of the robot, pass inspection and stay on the robot
2x4’s as in wood? Velcro wouldn’t be a very good mounting system for this, I can guarantee they’re going to fall off. As soon as they are attached to the robot they are declared part of the robot and must pass inspection as they are considered an addition.
The rules do not forbid the use of external devices to align the robot. The blue box in G8 is about delay of match schedule. That is, you may not cause a delay in the match schedule through use of external alignment devices. If you can get your alignment device in and out easily and quickly, it’s really no different than if you brought a screwdriver or diagonal cutters and tightened a screw or trimmed a zip tie.
In any case, what does this have to do with velcroing 2x4s to the robot? Any reasonably heavy part that is velcroed in place is likely to be in danger of falling off, and while not expressly illegal, is subject to failing inspection.
It’s OP’s team’s attempt at a work around for external lineup devices.
Tape a few soda straws to appropriate spots on the robot. Look through the straws to see arena landmarks that tell you you are in the right spot and are properly aligned.
Or put grooves/scratches or bumps (screw/rivet heads) into/onto the robot. Align the grooves/bumps with arena landmarks.
Or put paired bits of tape onto the robot. Align the robot so that arena landmarks line up with the gaps between the paired bits of tape.
Don’t overlook error sources (like slop in the initial state (tension, etc.) of the drive train belts/chains/gears) (or the nap of the carpet?) (or …) that come into play as the robot goes into motion (and that are likely to swamp any initial small alignment errors).
I see what you are saying. You use the 2x4’s to line up the robot and then velcro them back on. There is definitely a small hole in the rules but seriously does it matter.
What good are these 2x4’s going to do you.
you may as well add a tape mesure to your robot, it would be better, and weigh less
At our last event we used the wood to align ourselves with the guardrail so we could shoot low in autonomous. We used them about 3 times before a ref said that we couldn’t use them. We had no clue their were any rules in regards to alignment devices and we wanted to look closer into it.
If you’re still curious, the rule that would be cited is G8.
Emphasis mine.
Just a thought:
Your eyeballs ought to be calibrateable. How about marking the proper width on the robot, then using your eyes to measure where the robot is set up?
I have yet to see a ref disallow eyes as an alignment device. Shoes might be a little harder to use, but could be doable. Using the robot, or a section of robot, is a really good option as well.
At Lone Star we used a combination of a boulder plus our hand width to gauge how far away we were from the wall for our low bar autonomous.
I wouldnt rule out velcro as an option for holding a 2X4 if you get the industrial strength stuff. in 2013 my team had about 10lbs of steel as a ballast on our robot held on only by velcro. It might sound sketchy but the velcro was enough when we wanted to take the blocks off we had to hold down the robot as the velco was strong enough to lift it.