Don't Overlook the Low Rung!

If your team has (hopefully) come to the rational conclusion that the Traverse Rung is outside your team’s build capabilities, please don’t overlook the Low Rung! I can picture it now that many teams will design a climber that starts above the height of the Low Rung, and they will only be able to climb on the Mid Rung. Realistically, you can only fit 2 robots comfortably on any given Rung. One of the easiest ways to achieve the climb RP is to have 2 mid Rung and 1 Low Rung climb. If nobody is able to do a Low Rung climb then you’ll be out of luck!

Consider making it a design requirement that your Mid Rung climber can also climb the Low Rung. Alternatively, add 2013 style passive wedge climbers to your robot to enable yourself to climb the Low Rung, separately from a Mid Rung climb mechanism.


Related thread: Every team should seriously consider the low goal this year


Implementing a passive wedge climber for the low rung will prevent you getting to the mid rung, so a passive system will be most effective if it can be added or removed before each match according to your alliance strategy. This would be nice, as the passive unit would probably be faster than bringing your super-gear-reduced climber down an extra 12" to hit the low rung. Might be harder to make a passive climber at this height than for the bottom rung of 2013.

Alternately, having a climbing unit that can pop up to two different heights will let you design something with as short a travel as possible while not needing to deal with different mechanisms.

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Only if you approach the Hanger from the “front”


Oh wow, thanks for saying that. I was under the impression that the “side” of the hangar was walled in for some reason. It’s totally not.


I was a climb mentor in 2013, but I have no idea what you mean here. Can you please expand on this?

An upside-down wedge with a backstop and cutout. So you drive really fast into the bar, the momentum of the robot slides the wedge up over the bar (thereby lifting the robot), and then the bar falls into the round cutout, leaving the robot hanging a little bit above the ground.



Thanks. I saw several of those, but “passive” wasn’t how I would have described them based on the violence of using them. Further, few of those I saw worked because unless you get the notch in exactly the right place, the robot doesn’t hang straight and touches the carpet. (I’m not saying this to dissuade teams from doing this, but to let them know the pitfalls I saw so they can work around them.)

Well, it’s passive in the sense it’s not actuated (you don’t need a motor or pneumatic for the hanger). Putting the notch in the right place is a CG question and relatively easy to test/tweak to get right. But agreed these are things to keep in mind when implementing this.

Another very simple mechanism used in 2013 that might work for the #2 rung too is two vertical pneumatic cylinders with hooks on the end, just extend so they’re above the rung, drive forward until the hooks are over the rung, and retract them to lift the robot. You only need about 1.5" bore cylinders (or slightly less) to do this, as each cylinder is only lifting ~75 lbs.


@GeeTwo There is a video of a passive climber in our latest post

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