Modular Mechanisms in FRC

[fruits_and_pebbles]

I was wondering if it would be possible to create a modular robot. (Ex. A robot with removable mechanisms). For the 2024 game, it would look something like having climbers/trap mechanism that could be taken off to make the robot lighter during playoffs or something like different shooter designs (one with spin and one without). My questions are:

1. Are having modular mechanisms legal?
2. Are they viable? (Both mechanically and on the software side)
3. Have there been robots from the past that have used something like this?

[LuiTheFly]

See 4946 this year.

They had 2 “Robots”, one for qualification matches, and one without a trap mechanism for playoffs. Very, very cool talking to them at champs this year.

G209 - What defines "1 Robot"

4946 this year has a second robot specifically designed for playoff matches that is smaller/faster at cycling. By removing some things and making it light enough it “is not a robot” by rules definitions apparently. Definitely taking the rules to the extreme, and was cleared by inspectors at their event a few days ago. Not sure on the whole rules legality reasoning and such, but cool to see a team push the limits to get the most amount of performance. Both robots pictured here [IMG_1144]

[FinIce]

G209 - What defines "1 Robot"

4946 this year has a second robot specifically designed for playoff matches that is smaller/faster at cycling. By removing some things and making it light enough it “is not a robot” by rules definitions apparently. Definitely taking the rules to the extreme, and was cleared by inspectors at their event a few days ago. Not sure on the whole rules legality reasoning and such, but cool to see a team push the limits to get the most amount of performance. Both robots pictured here [IMG_1144]

1519 - One Dual-Config Robot or Two Robots?

NOTE – I originally hadn’t intended to ask this question of the ChiefDelphi community prior to receiving an answer to our pending Q&A from the FIRST Game Design Committee, but so many people have asked about what happened to our dual-configuration robot in the four days since the start of our week 1 regional that I am having difficulty justifying the continued delay to reply to folks while waiting for the official Q&A response… This year our team employed a strategy that piqued our curiousity i…

These are both fun threads for this. Specifically the first one is more applicable, and that one was cleared

Edit: Sniped on the first one, good job @LuiTheFly

[fruits_and_pebbles]

I have seen what 4946 has done this year; however, by modular I meant more of removing a main mechanism such as a climber/trap mechanisms. The robot would have to be on the same drivetrain unlike what 4946 has done with having 2 “separate” drivetrains.

[superdude311]

I mean, I can’t really see why it wouldn’t be allowed. I know you can get a mechanism inspected as “spare parts” or something that could be added to the robot, so I can’t see why the reverse would be disallowed.

[FinIce]

I think that so long as it is reinspected and made clear, it should be fine. A lot of the same rules would apply, so a close reading of them would help.
In fact, I103 seems to explicetly allow it, emphasis mine

At the time of inspection, the OPERATOR CONSOLE and the ROBOT must be presented with all MECHANISMS (including all COMPONENTS of each MECHANISM), configurations, and decorations that will be used on the ROBOT in MATCHES without re-inspection (per I104) and may not exceed 150 lbs. (~68 kg) (note that while up to 150 lbs. (~68 kg) of ROBOT MECHANISMS may be inspected together, the ROBOT configuration used in a MATCH may not violate R103). The OPERATOR CONSOLE and exceptions listed in R103 are not included in this weight.

A reading of Section 9 | Inspection and Eligibility is good, as it goes more in depth on what exactly can be done

[EricH]

Legal: yes. See the Inspection section of the Manual for requirements on how to do it.

Viable: open question. May be year-dependent.

Historically, these have tended to be rare, barring the traditional “make non-working mechanisms vanish for playoffs” maneuvers.

[Skyehawk]

We have also hashed this out several times before on this forum. See above threads linked by others before trying to hash it out again.

[Prinkle]

our collector and climb arms were modular in 2024. The collector was held on by 10 bolts attached to the drive train and swerve and out climb arms were held on 12 bolts to the drive train. Thank fully we never had to swap the climb arms but being able to quickly swap collectors was a big help in short match gap situations. At Michigan DCMP we had to swap 3 times all of which our pit crew was able to to do in under 5min.

[EmilyBread]

5188 had a removable superstructure (including intake and shooter) that attached to the base with only four bolts that threaded into aluminum blocks on our base. We also bundled all wires in one spot to allow us to disconnect everything very quickly. In practice, this allowed us to easily remove the superstructure for repairs while the drive base remained operational to maximize driver practice and controls testing time. We could take the superstructure off so quickly that we even did it in queue for a couple matches to debug wiring issues (which only slightly concerned our alliance partners when they saw half our robot on the ground).

We discussed making a SoD defense attachment that would mount to The Four Bolts if our intake or shooter ever broke, but we never got around to it. For 2025, we will try to implement a similar modular strategy if it makes sense for this year’s game, mostly so that we can build multiple iterations of mechanisms and quickly swap them out.