Using Second battery to Charge Tanks

[wilsonmw04]

Originally Posted by Mark McLeod

I assume you asked the GDC in a Q&A not some random volunteer.
I don't recall any such Q&A though.

I think your issue here is how the question is framed and (presumably answered by the GDC).

The answer you received appears to simply be addressing the issue that the compressor must be powered through the robot by the robot battery whenever it is operated.

And that is the question I think is core to my problem. When does the robot become the robot?
From my POV once you use the battery to compress air in your tanks, that battery becomes part of the robot for that match. If you removed the battery after the compression, you are using two batteries for a match.

Mark,
The question regarding swapping batteries was asked in the Q & A and they directed the petitioner to R69. I'm just not sure how that answers the question.

[Mark McLeod]

Originally Posted by wilsonmw04

From my POV once you use the battery to compress air in your tanks, that battery becomes part of the robot for that match. If you removed the battery after the compression, you are using two batteries for a match.

Then I posit that you cannot change your battery after you have used the energy to download any code that will be used in said match.

[wilsonmw04]

Originally Posted by Mark McLeod

Then I posit that you cannot change your battery after you have used the energy to download any code that will be used in said match.

I would disagree because changing code does not store anything that could do work for the robot.
Thanks for being lighthearted about this. This is not a hypothetical for my team. With such a large set of tanks this year, it take over one minute to charge our system. If we could do that with another battery it could be a substantial advantage for the team. I just don't see how it jives with the rules. I know others do it; the GDC is rather vague on the issue. I just don't like gray areas. It get's folk in trouble and feelings hurt.

[BigJ]

Originally Posted by Mark McLeod

Then I posit that you cannot change your battery after you have used the energy to download any code that will be used in said match.

Probably should just use the same battery you used to image the cRIO last.

[Mark McLeod]

I don't believe any rule supports your self-imposed position.
I don't beleve the GDC supports your position, otherwise, they would say so.

I believe only one battery can be used during a match.
A match begins with the field sound and ends with the refs all clear flag.
(it doesn't end with a field sound this season).

I don't accept the stored energy argument (even without the evidence of a rule), otherwise, springs, elastic tubing and other potential energy storage is also suspect. Thereby excluding human muscle power from the robot, as well, if the battery is the sole source of energy.

My beliefs don't constrain the GDC, but are what I will advise any team that asks.

I'm rooting for your students.

[wilsonmw04]

Originally Posted by Mark McLeod

I'm rooting for your students.

As am I. They are a great group of kids.

Dude, just saw you'll be at VCU in a week. I'll look you up. It will be nice to match a face to a CD tag.

[Mark McLeod]

Originally Posted by wilsonmw04

As am I. They are a great group of kids.

Dude, just saw you'll be at VCU in a week. I'll look you up. It will be nice to match a face to a CD tag.

Your honorable stance teaches them all they need to know to have a successful and fulfilling life.

I'm a mentor with team 2402 from Fredericksburg. I'm older than my photo appears (my hair is graying now) -that was taken more than 10 years ago.
I get around...

Go Rams!

[Mr. Van]

So... has anyone come to a conclusion on this issue?

It is very clear that the robot must be controlling the compressor when it is filling the tanks - on board or not.

There is a very interesting question regarding switching the battery after the compression is complete. For many robots this is not a real "game changer", but at least one example that's been mentioned on these forums is a robot that requires 7 minutes to compress its tanks!

This is roughly about 40% of the total energy output from the battery in the duration of a match.

Yes, it is legal to store this much energy in springs on the robot, but there is no rule saying that "springs must be stretched/compressed under the control of the ROBOT".

It seems to me that the answer to this question could indeed be a "game changer" in certain circumstances.

When does a robot become the ROBOT?

-Mr. Van
Coach, Robodox

[Mark McLeod]

To have the force of a rule there must be a clear interpretation from the GDC and uniform "enforcement" across all events. That's the rule "rule."

I don't mean "enforcement" in the sense that an authority such as the Lead Inspector must stand over us. It's on the honor system. We all want to do the right thing.
I just mean that the event authority (and in this case it would be the Lead Robot Inspector's responsibility) makes it clear that's how the rule will be read.

Since, teams have done this for year's under essentially the same rule set, I think it's a stretch to say this is a rule, much less a uniform interpretation.
From their Q&A response and actions, or lack thereof, I don't believe that the GDC agrees with this particular interpretation.
The Q&A response seemed to be that there was obviously no such rule limiting when the battery can be changed.

I think we are all leaving with the same interpretation that we came in with...
There is no way to prove an anti-rule.

[Joe Ross]

Do teams with onboard compressors vent their pneumatic system every time they change batteries?

[Matt Krass]

Originally Posted by Mark McLeod

Your honorable stance teaches them all they need to know to have a successful and fulfilling life.

I'm a mentor with team 2402 from Fredericksburg. I'm older than my photo appears (my hair is graying now) -that was taken more than 10 years ago.
I get around...

Go Rams!

He's lying, his hair isn't graying, its gray

I believe the intention of the ruling is to make sure the pneumatics are charged and controlled under the same rules and conditions (and safety systems) any other robot with the compressor on-board would have. This makes sense, and while cumbersome, I can understand it.

However I fail to see any way in which using a separate 'practice' robot battery bypasses any of those particular intended restrictions, or otherwise gives you an advantage or presents a danger, and thus I would have interpreted the ruling to allow you to swap your battery between charging the pneumatics and competing on the field.

That said, I'm only me, and my name isn't nearly popular enough to sway inspectors or refs ask the GDC for this exact situation. I believe they will rule in your favor, but having it confirmed can help everyone rest easier.

Matt

[Travis Hoffman]

Originally Posted by Matt Krass

I believe they will rule in your favor...

Famous last words?

[1708xMr.Roboto]

Team 1708 did this in Washington DC this year,

after our First regional we ended up dumping the compressor and the Clippard tanks, for some of the lighter PVC tanks so we could include a mini bot launcher on our robot. The way our system worked was like this, we had a onboard Spike and when the tanks needed charged (Between Matches) we plugged in the compressor to the spike, and ran the compressor off the robot's battery. You are allowed to do so, as long as you can prove that your compressor and code shut off at 120psi. after that was all said and done, we switched the robot's battery and were ready to rock and roll. This made being in the Finals interesting considering it took about 4 and a half minutes to fill the tanks; and we only had 6 minutes between matches

-1708

[MikeE]

Let's try a different tack.

Here is the FRC prime directive:

<R01> Energy used by FRC ROBOTS, (i.e., stored at the start of a MATCH), shall come only from the following sources:
A. Electrical energy derived from the onboard 12V battery (see Rule <R34> for specifications and further details).
B. Compressed air stored in the pneumatic system, stored at a maximum pressure of 120 PSI.
C. A change in the altitude of the ROBOT center of gravity.
D. Storage achieved by deformation of ROBOT parts.

Note that <R01> doesn't say energy can only come from one of these sources, but "from the following sources", so it's clear that they can be used in combination.
Some energy for running the cRIO, motors, etc during the match comes from the onboard 12V battery per <R01>.A
Other energy may come from stored compressed air per <R01>.B
Rule <R69> further restricts the earlier source of this energy to a 12V battery, but doesn't expressly state that it must be the same as that of <R01>.A

[Al Skierkiewicz]

MikeE,
Your response is the defining start of the compressor rules. Those rules that pertain to off board compressors are not meant to give you an advantage over other teams on the field that do not have an off board compressor. To meet R01 while allowing off board compressors, there needed to be some massaging of the rules. The give and take for off board is reduction in robot weight for a limited air capacity. That is all. Those teams with the compressor on the robot must control it from the Crio and so too should off board compressors. On board uses the robot battery and so should off board. There can be no advantage given in either case. While the current rules do not bring robot battery into the equation, teams with on board compressors can pre-charge their pneumatics and then change batteries prior to taking the field. That being said, the same can hold true for off board. Personally, I would like to see a rule allowing only one battery per match. There are many teams that are on the edge of efficient design that are depleting a battery in a single match. If we are trying to inspire, this is one area we have fallen down on the job.
However, with the variety of pneumatic designs we see, I am always fearful of teams in the queue with pre-charged pneumatics.

Mark,
It's time for a new picture.