Re: Al's Annual Inspection Thread
 

I don't think the teams doing this are doing it because their robots drain battery that fast, they probably are just trying to be more competitive and keep that much more energy in their battery if there is no penalty for doing so.

Re: Al's Annual Inspection Thread
 

In the IFI world this was the normal mode of charging. Get onto the field, turn your robot on, charge the tanks with either on board or off board compressor and step away.

Re: Al's Annual Inspection Thread
 

In OCCRA, we connect the compressor switch to an automotive relay which runs the pump. The pressure switch is still controlling the pressure in the system, just through a relay instead of the Cortex. That way, we can bring the robots onto the field empty, turn on the power switch, and let them pump up while team introductions and vex auto are running.

Re: Al's Annual Inspection Thread
 

How nice of John to look out for the health and safety of our volunteers.

(I think he's really afraid someone is going to whip out the fire extinguisher and make sure the entire robot—not just the self-extinguishing speed controller—is good and dead.)


At SVR, I had a conversation about better practices for the pneumatic system, and one very reasonable thing that came up was the idea that it's not really important from a safety perspective that the cRIO control the compressor (via robot code). Granted, the rules are the rules, so we have no such option for this year—but it would seem quite feasible to find a pressure switch with the appropriate current rating and triggering characteristics (e.g. not prone to oscillating on the margin of the pressure limit), and wire it inline with the compressor and power distribution block. (This could also be accomplished with a big, dumb relay and the existing switch.) For those teams that simply want their compressor to pressurize the tanks whenever they're low, this solution is simple and robust.

In fact, it's safer than the current implementation: there's no possibility of bad code causing the robot to ignore the pressure switch. It also renders the overpressure valve redundant to an even greater extent. (Which is great, because the overpressure valves are a hassle to set up properly, and they're often provided in the wrong configuration. Not to mention that they're not really rated for numerous cycles.)

With a relieving regulator on the low pressure side, actuators cannot overpressurize the high side. So the only way to overpressurize is via the compressor, which would be hardwired into a simple device designed to prevent that, rather than a feedback system with numerous other dependencies. It's those dependencies that give us the requirement that the off-robot compressor be controlled by the robot. Eliminate this dependency chain, and you solve the most insane part of the off-robot compressor problem—which, by the way, is as ridiculous as controlling a battery charger with the robot: sure you could, but why?

To top it all off, make sure to give teams the option to install feedback control, if they desire, by installing a pressure transducer in addition to the built-in pressure switch.

This would allow the tanks to charge whenever the robot is on. In some configurations, this could result in robot parts moving as soon as the switch is flipped, but that's not really any different from robots that use electromagnets (custom circuits). In fact, robots that leak air have the exact same theoretical problem: the lack of pressure could cause robot parts to move uncommanded...and I don't see leaky robots being banned. (Though maybe they should be....)

Note that the above presupposes that the compressor, even if off-robot, is powered by the robot (and therefore benefits from the hardwired pressure switch). I'd even be willing to entertain non-robot-based sources of air, provided that that there was an appropriate overpressure valve installed on the robot, and that the delivery device contained a gauge (and a regulator or other relief valve, as necessary) demonstrating to any observer that it was delivering no more than the maximum allowed pressure to the robot. And of course, whatever this device was, it would need to satisfy venue rules—so don't bring in a floor-mounted shop compressor.¹


That's a longstanding annoyance of mine as well. Obviously you can't enforce the entire rulebook based on the state of a robot undergoing maintenance. As best I can reckon, the rules are unambiguously intended to apply during an inspection, and during gameplay. (If it's a full inspection, then all of the robot rules should apply; if a partial one, then only the relevant ones. If it's a game, everything applies.) This means, as a practical matter, that some rulings have to be made as the robot is placed into the starting configuration before a match: it's not illegal until you try to play with it. Until that time, teams have plausible deniability with regard to configuration issues.

Although I hesitate to frame it in these terms, getting "inspected" (i.e. a partial inspection regarding one violation in particular) right before a match is probably preferable to the inspector reporting the same violation to the referee during or following the match. If before, you've got a moment to fix the problem—in this case, simply dump the offending air. (In theory, there does exist the possibility that the team can't fix a problem, and therefore the robot could be prohibited from taking the field.²) By contrast, if the issue is reported during or immediately after the match, the sanctions from the gameplay section could be imposed (starting with a <G30> penalty, and taking it from there).

I also note that as a practical matter, inspectors will exercise discretion as to what violations would merit either of the above responses, as opposed to those violations which are minor enough to address after the match.


I don't like the sound of that. They might as well have phrased it, "read our minds, because we're too lazy to think about the consequences of what we've written"....


¹ Speaking of venue rules, since compressed gas cylinders are prohibited (to teams), that neatly rules out scuba tanks and the hassles involved with evaluating 3 000 lb/in² regulators. I sometimes wonder if that's the hazard that FIRST was trying to avoid, when it banned all non-compressor sources of air.
² It's my considered opinion that the 3-way red card for showing up for a match having an uninspected robot (<T03>) should only apply to a robot that did not ever pass inspection at the current event. The rules aren't clear about it, but that's a fair reading that gives the benefit of the doubt to teams, while maintaining what I would guess to be the primary intention of the rule. So, in my unofficial opinion, if you ever did find yourself in a situation where an inspector deemed the robot illegal right before a match, at least you could participate without completely ruining things for your alliance. (Best to have a pre-match conversation with the head referee and that inspector, if this ever comes up.)

Re: Al's Annual Inspection Thread
 

+rep for using footnotes!

Re: Al's Annual Inspection Thread
 

Not all power. Just all electrical power.

I don't see anything wrong about having the pneumatic system charged before connecting the battery you're going to use for the match. I don't even understand why it's controversial.

Re: Al's Annual Inspection Thread
 

I think this controversial issue in this thread is more the ability (or lack thereof) of teams to bring a second battery and pneumatic system in order to charge the one on the robot before the match without draining their match battery. The fact that pneumatic system is charged before a match is perfectly legal. The illegal issue is the using of a second battery pre-match.

(emphasis mine)
These rules disallow the use of any other battery than the one on the robot. Therefore, it is illegal to charge pneumatic systems with any other battery pre-match. It would be legal to have the system charged before entering into the queue line EDIT: starting a match , but past that point, it would become illegal.

Re: Al's Annual Inspection Thread
 

I don't see where your assumption that the rules start applying to the robot when it enters the queue line and not before is derived from.

I am much more inclined to agree with the interpretation that the rules apply to the robot during inspection and during the match itself.

Re: Al's Annual Inspection Thread
 

My use of the queue line in that example was more of an arbitrary point of when it becomes illegal. That isn't specified in the rules anywhere, and it probably wasn't a good decision to include that as a point. It just seemed to me that upon entering the queue line, it becomes much more problematic for a team to backcharge their pneumatics (my team got stopped for doing this in queue last year in Atlanta). Anyway, I'm sorry for using my own assumptions instead of the rules.

Re: Al's Annual Inspection Thread
 

I'm pretty sure that you guys that are making up your own rules about the robot queue should be restricted to ONE battery for the COMPETITION as the rule clearly states. :ahh:

I'm pretty accepting of pneumatic energy being listed separately from electrical energy as a separate allowable source.
And I'm very sure that the intent of the one battery rule is solely to prevent us from driving around during a match being actively powered by two or more 12v batteries.

Re: Al's Annual Inspection Thread
 

What happened to not lawyering the rules?

It is quite clear the rules mean that DURING the MATCH power can only come from one battery.

It is not saying that at any point in time, all non electrical stored energy on your robot must have been generated by the battery that ends up on the robot during the match.

Re: Al's Annual Inspection Thread
 

By <R01> there are 3 non-electrical sources of energy allowed on the robot at the start of a match.
Each source of energy is given equal ranking with all the others. Electrical does not rule over any of the others.

Re: Al's Annual Inspection Thread
 

By this logic all spings, surgical tubing etc. would have to be extended by use of a battery (never mind the competition battery). That means designing and building special motor driven mechanisms purely to pull a spring or piece of surgical tubing into a starting configuration, rather than do it manually.

The more parsimonious approach is to take <R01> as written and accept any (safe) original source of energy to be converted to the allowable stored energy devices.

Re: Al's Annual Inspection Thread
 

Not being very well versed in pneumatics, this thread has certainly taken an educational turn!

Personally, I don't have a problem with teams using a battery to charge pneumatics, and then a different battery to run the match - I think that is clearly within the rules.

However, I do have to acknowledge the potential safety aspect involved here... Turning on a robot while in line to charge pneumatics only provides a chance for mechanisms to act unexpectedly (as someone accidentally leans on controls, for example). Thus far, all of the systems I've seen have a single storage portion, that vents to the pneumatic solenoids to be controlled - it would seem simple to put a manual valve in place there to manually turn off the working portion of the pneumatic system, and allow safe storage. Then once on the field and in position, that manual valve could be turned, allowing the system to "go live" in a safe way - much the same as safety pins and lockouts that teams put in place during transport and pull once they are on the field.

Thoughts? This could be a nice safety feature...

Re: Al's Annual Inspection Thread
 

the pressure would drop as soon as you connected the two halves so you would start with less air.