Hanging on the switch with a small robot

Our team is thinking of doing a small robot (small enough to pass under the trench) but it has to climb the switch. We’ve seen some hangings of previous years, such as 2017 and 2016, but i think this year we can’t throw projectiles, right? That leaves us with really fewer options, I’d like your advice on that, please.

“we can’t throw projectiles”…this is a SHOOTING GAME. If you are talking about tossing up a cable, I do not remember seeing that has a prohibited action. You have a cable connected to it so its not really a projectile per se. What rule specifically are you referring to?


You could explore options like a multi-stage unfolding arm, or deploying feet out the bottom of your robot at the same time as a hook of some sort out the top of your bot.

Yeah, i’m talking about throwing a cable with a claw to get hanging on the switch or something like that. Didn’t saw on the rules, but a mentor of mine said we couldn’t use it

Yeah, but i think that would get the mass center unstable, right? I dunno, the only way to keep it stable like that it’s throwing or expanding something from the middle

Maybe I’m not understanding what you’re saying here; I don’t see how this would upset your center of mass. If you’re worried about the switch being level, you could implement a wheel that you hang off of to center. If you’re worried about your robot’s CoG, I don’t think that would really matter as long as it is in a place where it causes the switch to be level.

as a mentor, I can tell you that mentors are sometimes incorrect. This is all about the written rules, go read them and prove it to yourself!


ok, I’ll try and see it on the rules

ok, just saw, and nothing about that! there were a part where it says a robot may not intentionally disassemble, but not in the endgame, so that proves we can! thanks for opening my mind

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Yeah, maybe i said it wrong, it’s the CoG. You’re sure about this? I mean, even if I do launch a claw to hook, it couldn’t upset my CoG?

Unless I’m really misunderstanding you, I don’t think it would. If you have a hook attached by rope, your COG will be directly below the hook.

One thing you have to be careful of with a grappling hook is exceeding the 12" zone from your frame perimeter. It’s easy for a projectile to go outside that zone, and since you’re using it to climb, you could get a red card if it did.


Team 148 did this in 2016 if anyone is interested.


Hmmmm, I understand. Yeah, it should be really precise. I was thinking of something like 118 did on 2016…

118s worked so well in 2016 because they could ram up against the wall and be in the same spot every time. This year, there is nothing to ram against in the middle of the field.

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yeah, but in that case the robot had support on the field, i mean, they used a wall as support. in 2020 case, it would be like a pendulum, because it’s just the hang.

It should be noted that there are some major drawbacks to grappling hooks, such as 118s in 2016. If you miss the first shot, then you are a fish out of water. No second chances. Couple that with not having a solid alignment method for the grappling hook, and it makes it very difficult to actually pull this off. Even 118 didn’t pull it off regularly in matches that year.

It is a cool idea, in theory. Very difficult in practice.

The 2016 game had many examples of hanging robots trying to solve a very similar problem - how to go from short to tall and then pull up. This would be a great place to look for ideas.


One thing to keep in mind at all times, is that pesky 12" extension rule. You want to prevent any part of your hanging mechanism from going past that. If it’s a hook on a string, and you miss the shot, etc. Or if it’s not a rigid mechanism, and you winch yourself up, and the robot tilts to one side, you could exceed the permitted extension.

So…perhaps something more rigid, that unfolds, might be the way to go. There’s still time to figure it out.


Note that a grappling hook itself isn’t a bad idea – you need a hook that will bear the weight of the robot, and grappling hooks are designed to do that. (Most of the hooks you get at, say, Home Depot, can only hold a fraction of a robot’s weight.) You just need to have it delivered by something more solid than just tossing it up in the air and hoping it catches.