We are looking at having alot of tanks on our bot this year. Can we fill our tanks before tbe match? We are hoping to complete this by using an external battery to power our on board compresser, then plug it back into the pcm (we are connecting it with anderson connectors). Is this legal or should we ask the q&a?
Let us know,
FRC Team 2906You can pre-fill your tanks, but not by bypassing the control system like you proposed. Just connect your robot to your driver station via ethernet cable in your pit, enable the robot until the compressor shuts off, then put in a fresh battery. Just make sure you aren’t set to run autonomous when you enable.
That definitely isn’t legal by R85. You can only power the compressor through the robot control system. If you have an onboard compressor you can just enable your bot in queue, though.
I don’t see the need for the off-board complications. Fill your air system normally then swap in a fresh battery.
You cannot bypass the control system to use the compressor like others have stated but is legal to use a different battery and pre-charge your air tanks
Also R84 “one and only one compressor”. If you have a compressor on the robot, then that is the only compressor you can use, including pre-fill.
What about a bike pump / foot pump and a schrader fitting? can that be used to fill the tank in queue rather than enabling the robot?
That would mean the ROBOT would get compressed air from a source other than the one compressor, which violates R84.
I’d also note that by “another battery” that should be another legal FRC battery, through a standard battery connector, etc.
The whole point of this portion of the pneumatics rules is to mostly limit the stored power on the robot to what’s supplied by the ONE legal battery powering the ONE legal compressor. Onboard or offboard compressor, airing up your robot should be exactly like it was running an onboard compressor on the field during a match. Ask yourself if what you’re doing is something that’d be legal during a match, minus size/weight constraints for an off-board compressor. If it’s not legal during a match, it’s not legal in your pit in prep for a match.
This means you should think about your air consumption and how well your system would work with a 6 minute field timeout between Finals matches. If you can’t fill your tanks from empty or end of match level to full enough in 5 minutes, you’re using too much air.
As others have stated, charging your pneumatic system with anything other than that provided by the rules could result in any decision by event Chief volunteers. If stored air is important to your strategy then do not risk it by charging your system by any method other than that provided in the robot rules.
RTM ::rtm::
R43. 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:
A. compressed air stored in the pneumatic system that has been charged in compliance
with R84 and R85,
B. a change in the altitude of the ROBOT center of gravity,
C. storage achieved by deformation of ROBOT parts,
D. closed-loop COTS pneumatic (gas) shocks, and
E. air-filled (pneumatic) wheels.
R84. Compressed air on the ROBOT must be provided by one and only one compressor. Compressor
specifications must not exceed nominal 1.10 cfm (~519 cm3/s) flow rate @ 12VDC.
R85. The compressor (permitted per R84) may be located off-board the ROBOT, however the
compressor must still be controlled and powered by the ROBOT when used.
The compressor may be mounted on the ROBOT, or it may be left off the ROBOT and used to pre-charge compressed air in storage tanks on the ROBOT provided the additional restrictions of R90 are met. The intent of this rule is to permit teams to take advantage of the weight savings associated with keeping the compressor off-board. However, using the compressor off-board of the ROBOT does NOT permit noncompliance with any other applicable rules.
Rules are unambiguous on this topic.
I think “one and only one compressor” is ambiguous and so we’re going to use 3 or 4 of them. And a foot pump.
:rolleyes: :rolleyes: :rolleyes:
You can only use a different legal battery if it is the only battery in the robot, powering it as it would be during a match. As others have said, this should be done before you swap batteries.
FIRST ought to just supply an air compressor field side at the queue which each team can use to fill their tanks. This would solve what is always a problem every year with teams misunderstanding the rules. Would cost $300 per field.
I second this notion. Even though its not going to happen this year. crosses fingers
There’s little reason for the 1.1CFM limit on the compressor aside from a conscious choice by the GDC to limit how quickly you can store energy in the form of compressed air. That being the case, you’ll see free stored energy available field side about the time the GDC removes the flow limits on robot compressors. I’m not holding my breath for that.
Also, teams misunderstand the bumper rules every year too. It’s still unlikely the GDC is going to back off on them because looser bumper rules mean both flimsier bumpers and more teams engineering bumpers for a competitive advantage like wedging.
third
I’ll +4
I don’t see how flow limits are at all relevant to FIRST providing an air charging station. You still have the same flow limits once the match has started. The analogy about bumpers doesn’t make any sense. It’s nowhere near a comparable situation.
It’s currently free energy. You just have to swap batteries to do it. It makes far more sense to just quit all the worrying about shop compressors in the pits and whether teams are using offboard compressors correctly and provide a compressor that every team uses to fill up before the match. Every robot is functionally identical when it is set on the field as it would be currently.
We did this in 2012, and my advice is to make sure that your pneumatic system is as leak free as possible. It is likely that you will run into the situation of a delayed match start or a timeout, and when that happened to us, we made sure to recompress after each delay.
We saw this as an inconvenience and have not opted for an offboard compressor since. This was only done because our 2012 robot was designed to be short enough to hold another robot on top of it, so there was literally no space to place an onboard compressor. Those compressors were bigger than the ones used now if I recall right.
I would only advise doing this if there is absolutely no solution to the issue of space for an onboard compressor.