Rules on Swapping out Sub Systems

Hi All,

In my teams quest to come up with the best intake system for Hatches and Cargo, someone came up with an interesting idea: Why don’t we have two separate sub systems that we can switch out biased off our alliance partners?

The thought is that for the majority of matches you will likely be paired with hatch capable robots (as we predict the Hatch ability will be far more common), therefore it would make more sense to do cargo; however, on the off chance we get paired with 2 other Cargo only bots (or malfunctioning), we would need to ability to do hatches in order to score any points.

From what I can tell from the rules, it seems to be legal.

However, the rules aren’t exceptionally clear on switching out very major components of a robot, at least not in my opinion. My hope was that someone has experience with something like this in the past? Has anyone seen this be done before? Does it seem legal or practical? Id love to hear input.



R5. The ROBOT weight must not exceed 125 lbs. (~56 kg). When determining weight, the basic
ROBOT structure and all elements of all additional MECHANISMS that might be used in different
configurations of the ROBOT shall be weighed together (see I3).

It’s worth clarifying in the official Q&A when it opens, but in the past, this is how it’s been handled:

  • If everything together weights 125lbs or less, then things are a little easier for you. At inspection, we weigh everything together, inspect one configuration, have you change it out, and inspect the second configuration. We note that you have two legal configurations and you can swap between them without any additional inspections needed.
  • If everything together weighs more than 125 (for example, your base robot weighs 110 and each of the two mechanisms weighs an additional 10 lbs - at any one time you would be 120, but with everything together it’s 130), then you can still swap between them… but you have to get reinspected every time you change configurations.

The first point works because everything together is legal - each playing configuration is legal, as is the weight of the robot with all mechanisms present. The second one works because one of the mechanisms isn’t “present” during inspection, so it doesn’t count towards the weight. When you swap it out, it’s like any other change and you get reinspected, with the other mechanism no longer “present”.

If you go with the second route, please be aware that inspectors will do what they can to help you get through each successive inspection, but you will be subject to their availability just like any other team. If you make the swap and an inspector isn’t available, you could miss a match as your robot wouldn’t be currently “inspected” in that configuration.


If it is a major change you will have to be reinspected. I would put the extra subsystem inside your bag so it doesnt affect your weight allowence for prebuilt parts. Last year my team removed our ramps when we were going to be lifted to reduce our weight and all it was was a reinspection.

So essentially, if we are able to keep all of our subsystems bellow 125 combined with the robot, their would be no need to reinspect?

The idea would be that we could change out the subsystem in less than 2 minuets to easily get between matches, so getting reinspected definitely gets rid of that ability.

I appreciate the help! Ill make sure to get the question asked tomorrow during the Q&A :grinning:

That’s how it’s worked in the past. That’s what the “all additional mechanisms” wording in R5 is all about. Weigh everything together, and if it comes in under 125 you’ll be good to go.

If you can really swap the two mechanisms that quickly, you’ll impress some inspectors, too. Very few teams can even put their bumpers on that quickly!

Hopefully it could win us a creativity award as well!!:wink:

And make sure that the inspector verifies and approves both/all configurations during your inspection (and any re-inspections for other changes).

Definitely! Thanks!

I would also take it one step further and make sure the LRI knows/sees both configurations. If any questions come up on the field, they’ll be addressed to the LRI, not to whichever inspector you happened to have!

Smart. Should we ask directly the LRI to inspect us on the grounds of us having a unique situation? Or should we just mention to do the inspector that we get, that we would like the LRI aware of the situation as to ensure that they’re no problems? Or is their a specific route that we should take?

The LRI probably won’t have time to inspect you themselves (we can be very busy helping all of our inspectors and teams!). I would ask to speak with them when you go up for inspection, explain what you’re doing and let them guide you through how they want to handle it. If it was me… I would look at both mechanisms as they were (one on the robot, one off), and have an inspector handle the actual inspection. That would let me know (more or less) what both configurations look like AND that my inspector knew to look at both before passing you.

Whether the LRI does the full inspection or not, he/she should know about it.

And the LRI should tell the Head Referee. You come out onto the field with your “new” configuration after having played with the “old” one a few times, and you might be questioned whether or not the new configuration was inspected.

Thanks to everyone for the help! Ill let you know if we go through with the idea!