PSA: A Warning about Climbs in 2020

Forgive me for the hyperbolic title… but it got you here didn’t it :wink:

With Ri3D wrapped up, and most teams determining a set of priorities by this point in the season, it’s starting to become clear that climbing will be a critical part of Infinite Recharge. If you didn’t already figure that out, take this as a hint.

In full disclosure, this Public Service Announcement is being done purely out of my own self interest. I WANT CLIMB RANKING POINTS! I want alliance partners that I can balance climbs with.

Most Ri3D teams have converged around a similar climbing style that has been very common in recent games. Non-loadbearing extendable mechanism reaches up to “drop a hook” which is then winched up to lift the robot off the ground. Ri3D teams have proven it works, it’s been done hundreds of times in recent years, why wouldn’t we all do it this year?

I’ve seen some static load diagrams that show the wide range in which two similar weight robots can climb and still be balanced… but you know what? Real life isn’t static! When you drop a hook and winch it up, your robot has the potential to swing back and forth! I’m willing to bet we see more than a few matches this year in which a climb would’ve been balanced if it weren’t for a swinging robot.

There are a few ways to improve all of our chances of getting the climb ranking point. First, if your packaging dictates that you need to “drop a hook”, make sure it’s in your center of gravity… if it’s not, you’re more likely to sway back and forth, as well as you might tip in a way that makes you illegal. Hopefully your component packaging isn’t so restrictive one week into the build season that you’re already constraining yourself to an inferior climbing method.

A rigid climbing mechanism will be superior to any sort of cable and winch this season. A rigid climbing mechanism will help to ensure you don’t sway back and forth and ruin your alliance partner’s dreams of getting the climb RP. If you have the ability to design a rigid climbing mechanism, spend the time to do it, it will make you more valuable in quals and in the playoffs. Packaging this type of mechanism is also a great justification for many teams to build tall robots.

Another solution for maximizing your potential for earning the climb RP include coordinating with your alliance partners and climbing at the same time such that the bar remains level while you both go up. Coordinating these types of things in quals is challenging but not impossible, and certainly worth trying.

We’ll see some other more outlandish and brilliant solutions to climb balancing… but do yourself a favor and start making these considerations now.


The Snow Problem robot rocked quite a bit during its climb, but the switch was pretty much at its max tilt right away. SPOILERS:

I can see some variation in angle of the switch if robots are violently accelerating up and then smashing into the bar, but until I see some other videos I don’t think swaying a bit will be much of an issue. (also I am firmly in the rigid body camp)

I wholeheartedly agree that alliances need to coordinate their climbs. Itchy joystick fingers will likely be more of an RP bummer than swaying robots.


I’m hoping for but not necessarily expecting a lot of pre-match planning involving knowing the exact weight of the two climbing robots so the teams can figure out how to arrange themselves on the bar for maximum chance of climbing success. I figure inspection is going to be busy re-weighing a lot of robots for this purpose.

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I hope some teams just bring a scale to their pit.

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Scale big enough for a robot isn’t super easy, cheap, or transportable. The inspection scale is right there and it’s hardly ever used after the big rush to get everyone inspected. And you only really need to get the robot weighed once, provided you write the result down somewhere.

I think it’s worth pointing out that the actual field switch is pivoting on iGlide bearings and has more inertia than the team version. I don’t think this is going to be the 2012 featherweight bridge level of fiasco, but I also don’t think balancing on the real switch is going to be nearly as easy as the team version.

I was just imagining us bringing our scale that looks like this and 2 2x4’s for teams to weigh their robot on.



I predict a LOT of teams will be shocked and upset when they receive a penalty rather than climb points for their endgame efforts. Be sure to have your alliance partners demonstrate how they hang before going on the field with them, kiddos.

edit: G18. I’m not clear if the climb is disallowed, but I do know that you’re either getting a foul or a red card, depending I suppose on the interpretation of the word egregious.

edit edit: G18-b doesn’t leave any room for interpretation; extending outside the 12" allowed in order to score a climb is egregious, period, and therefore a red card. Don’t do it, y’all


I feel like momentary (officially defined as < 3 secs according to FIRST) extensions past 12in because of a swinging robot on a string is very far away from egregious.
If FIRST really wanted to they could add a “G18 violations during endgame in the RZ are a yellow card as well as a foul” to mimic the extending too high rule during HAB climbs last year. Otherwise a team could easily just eat the foul and get the climb + level + RP points and its completely worth it if necessary.

Yeah I’m not thinking a a momentary swing, more like a 70 degree tilt from placing their cable on the far side of their COG

Yeah that sounds egregious and if you come to rest while violating G18 there should be a way to invalidate that climb. I don’t see that in the rules currently though


Yes that is correct according to the rules. I believe the same drawing is in the rulebook.


Assuming both robots are centered on their sides of the bar, an 85 pound robot can balance a 150 pound robot. I wouldn’t worry too much about weight differentials.


G18 says nothing about climbs. If the robot meets the definition of a climb, the alliance gets the climb points.

If G18 is violated, the violating robot gets a red card. It doesn’t gain any of the RP for the match. The alliance itself is unaffected during a qualification match. If this takes place in an elimination match, the alliance gets the red card.

Feelings aside, the blue box for G18 is pretty clear.

b. extending beyond the FRAME PERIMETER to score a HANG

As there’s no mention of momentary, the game manual specifically calls out ANY extension beyond 12" to score a hang is egregious. Momentary. Extended. Violating G18 during a climb is a red card for the robot. Don’t let feelings get in the way of reading the rules. It’ll lead to a very frustrating experience later.


I think teams depending on balancing at the exact edge of the envelope are going to be rather disappointed with their results. I don’t think the switch is going to damp itself nearly as quickly as everyone is expecting.

Sure, but nobody builds an 85 pound robot (with batteries and bumpers) that can also climb. Two full weight robots can balance each other from almost any position, and the window is still pretty huge for a ~30 pound mismatch.

I wouldn’t be so sure. If you have looked at the field tour video on the hanger, it is actually really tipsy and doesn’t compensate itself. Positioning will highly matter if you want to hit the window in which the hanger is considered balanced. Type of climb will also be a huge factor, as some of the Ri3D climbs have shown us some robots may swing. Which in a situation that you have to climb quickly could be detrimental.

Oh I didn’t notice that thanks for pointing it out!

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