Is it still legal to have a pneumatics system with no compressor, just air tanks mounted on the robot?


I wonder what the lightest legal compressor is. If there exists a tiny compressor that weighs way less than the standard Viair one, you could use it to pre-charge your tanks before the match. A low CFM would’nt matter since you’re essentially relying on it to pre-charge your tanks.


those of us who were around in the days of the Thomas compressor have a better understanding of why the off board compressor was allowed, in the first place. Since we’ve started using the little Viair compressor, I haven’t found any reason to go off-board.


One reason for offboard compressors was 2.55 lbs. of additional mechanisms…


I’m not sure if this counts, but it only weighs 4 oz. If you apply 12 volts to it you won’t get more than 1.10 cfm out of it, so it doesn’t really violate R86.


My best guess is the charging of some rather large air tanks with batteries not on the robot. There is a lot of potential energy in a 1 gallon tank at 120psi, that takes a bit of energy to put there. Thus an unfair advantage by having that volume of air available at match start.

Sure, most teams with onboard compressors (I would guess), charge airtanks pre-match. I am sure a significant portion of that subset swap the battery after the fact if it is convenient (swapping the battery after charging has been against the rules for years, but this is difficult to regulate (pun intended)).


Can I get a rule number on this? I have never seen a rule prohibiting swapping batteries after charging pneumatics. My teams have been doing it for years, sometimes right in front of inspectors, and have never been called out on it. If it is against the rules, I’d like to know.


This is also untrue. The rules have never explicitly specified that you have to charge your pneumatics with the same battery you go into a match with. The rule simply stated that the compressor had to be powered by the robot. Perhaps an overzealous inspector interpreted that way, but that wasn’t the rule.

In any case, it doesn’t matter because offboard compressors are illegal. Why would the rule specify that air must come from an onboard compressor if it didn’t have to be… onboard? That’s what the word means.


R46. Non-electrical sources of energy used by the ROBOT, (i.e., stored at the start of a MATCH), shall come only from the following sources:
10 ROBOT Construction Rules V0 79 of
A. compressed air stored in the pneumatic system that has been charged in compliance with R86 and R87,

While the don’t specifically allow you to swap batteries after charging the pneumatic system, it allows stored air at the start of the match. You won’t find a rule against swapping batteries after. It is common practice to do so.

As a side note off robot compressors were required to use the robot battery run the compressor so you didn’t gain anything in that respect.


Actually one of the bigger reasons we went with an off board compressor last year was to not have a compressor running off our battery during a match producing excessive air pressure that would not be used. The weight saved was nice, but having less load on our battery and more available power for other motors was much nicer.


You can fix this programmatically if you’d like.


This is really the major reason to use an offboard compressor in the last several years. The reduced current draw is a significant advantage.

Fortunately, with an onboard compressor you can just disable it to prevent this current draw in a match, but devoting weight and space to an object you literally never use in a match is frustrating.

  1. You can programmicaly turn your compressor off when ever you want and then renable control of the compressor to the PCM/pressure switch when ever you like as well. The only thing you can’t do is directly turn your compressor on bypassing the pressure switch. We regularly don’t allow our compressor to turn on during Auto or high load situations like climbing in 2017.

  2. Off-board compressors complicated inspections. As an LRI part of my training for other inspectors was to just come find me for all off-board compressors because I had to confirm that the team followed the rules and I had to give their entire pit and drive team a very stern warning to not use compressors that weren’t controlled by the roboRIO. I have had teams fill their robots with shop compressors, compressors that they built into back packs with batteries inside, teams trying to charge with two compressors and swap back forth cause they worried one was getting hot. The off-board compressor rules were being followed inconesently by a lot of teams.

  3. Your weight limit is now 125lbs, you have room to make it fit.

Just to be clear, I am in favor of this rule change but my preferred rule change is to require the McMaster 125psi blow off valve then allow teams to use what ever compressor they want, including filling the robot from a shop compressor, off board compressor, off-board and on board, etc. I’m not really sure why we care where the 125psi comes from before a match.


I believe it is primarily due to concerns of excess electrical load in the pits from running a shop or large compressor.


Inspecting in Vegas, this is the number one reason they weren’t allowed. Safety was just an added bonus.

If it’s in compliance with the rules, calling it unfair is well, unfair. We had a 3 gallon tank on our robot in 2015 that took a few minutes to charge.


Dude, can i get a rule number? I’d hate to be breaking the rules but every ri that has seen us do it has never said anything.


That should be a venue rule and not a robot rule. Several tool manufacturers now sell battery operated compressors, we own a Dewalt 60v portable compressor. The current system doesn’t ban the use of compressors for tools in the pits (unless they changed the “evergreen” rules and I didn’t notice).


This was already disallowed before Team Update 01 by R85 [fixed]. This year, there is only one plumbing schematic; the one with the off board compressor which has been in previous rule books (see R86 and R91 from the 2018 game manual) are absent.


Pedantically it is forbidden by R85. R84 lists the legal parts, R85 defines the legal circuit.

Team Update 01, modified R86 to make the “onboard” requirement painfully clear.


And now the Q&A has prevented any “off-board” devices to charge the air system.


If you do not want to run your compressor during the match pulling current from your battery, there is a simple fix for that. Even easier than programming it “off”, just pull the breaker out of the PDP for the spot where the compressor is wired. Bingo, no running compressor until the breaker is replaced.