Re: Pneumatic Restrictions & Improvments
 

There is one other potential reason for teams to want to use "shop air".

If you've got a properly sized compressor, you've got a very reliable and steady source of power for your tools, and possibly smaller tools to transport. If you use a cordless tool, you'll probably run out of charged batteries at some point, particularly if you've only got one or two batteries to start with. And if you've used corded tools, they're only good for as long as their cord, or you're using an extension cord, while an air line coils neatly but extends as long as you'd need it.

Re: Pneumatic Restrictions & Improvments
 

One of the reasons many teams love pneumatics is the speed at which they actuate, I seriously hope this does not become a rule. We loved having the ability to use a valve with a higher Cv value this year specifically.

For pressure sensor, check out this one from ebay, we used them on the robot this year to monitor both high and low pressure sides of the system.

Re: Pneumatic Restrictions & Improvments
 

+1 One the pressure sensor, We used it last year (Thanks CD for a previous post recommending it). It a was key factor in a QF buzzer shot for a win.

Re: Pneumatic Restrictions & Improvments
 

It would be difficult to manage this rule, yes, but I think this would encourage better quality in pneumatic work. I won't name any specific teams/years, but I have seen a number of robots with a ridiculous number of tanks, that still struggle with having enough air in match.

That makes sense. Perhaps rules could be changed to allow any teams to use external compressors, but specifically state that two compressors can't be used at the same time? My team always uses on-board compressors and we've never had any serious problems with having enough air in-match, but with some of the crazy things we saw teams doing with pneumatics this year, it would be cool to see more relaxed rules in the future.

At the events I've been to, it doesn't seem like a lack of trust, but inspectors are strict. This hold teams to a high standard, and inspectors are generally very consistent. Also, on the topic of shop compressors, my team has never encountered trouble with having a compressor in our pit. We use it almost exclusively for our rivet gun, and it stays hidden away inside of a cabinet when not in use.

Re: Pneumatic Restrictions & Improvments
 

We were allowed one type of tank and up to 4 of them. It was really simple to check.

Re: Pneumatic Restrictions & Improvments
 

I've inspected since 2009 at many events. Never have I had a LRI even hint at distrusting teams in the above (or similar) situations. That's why I was concerned when a LRI literally stated (although it was slightly unclear) that at LRI training they were told to not trust teams to use shop compressors to not fill robots. Although now it seems like that's his personal view, and not what was conveyed at LRI training?

Either way, I've found more than half of my time inspecting is actually protecting teams from other inspectors with flawed interpretations of the rules. Too many inspectors (rarely LRIs luckily) have a seeming "Us versus them" mentality, rather than focusing on how to work with teams to get them the best experience they can.

Re: Pneumatic Restrictions & Improvments
 

Don't you just love when people on a forum take something you say, twist it around, and start beating you with it every chance they get? No where in anything I said did I say I didn't trust teams to do what they thought was best and legal. No where did I even imply that anything we look for at events is because we suspect teams of cheating, as opposed to acting out of ignorance (which is probably 99.9% of what we see as inspectors).

You'll note that I never said anything about not trusting teams - the word trust wasn't brought up by me. I simply pointed out that we don't know if teams are using a shop compressor to charge their robot, and that's one reason we don't like having them present in the venue. It's not a question of trust any more than any of the other rules we enforce at an event - it's a question of "what is that freshman who doesn't know the rules going to do when the pressure is on and he's sent to get the robot ready for the match?" Many, many teams use a shop compressor during the build season to power pneumatics for testing - I know my team does, and everyone on my team knows how to do so safely... and it's quite possible that one of my students, out of ignorance, would use a shop compressor to charge up the robot when in a time crunch/pressure situation.

Re: Pneumatic Restrictions & Improvments
 

My apologies then, it really seemed like you were implying you didn't trust teams to do the right thing.

Re: Pneumatic Restrictions & Improvments
 

Agree completely

We used the same sensor as well with great success.
Maybe AndyMark or IFI can start stocking a pneumatic pressure transducer?

VEX robots also could use a pressure transducer !

Re: Pneumatic Restrictions & Improvments
 

+1

The older rules were pretty good at keeping the playing field standardized.

I really like the increased volumes of air storage with the new rules but we could write the rules like the motor restrictions of the banebot motors or the bag/mincim. "Your allowed X amount of the following approved tanks"

So teams could max out volume with the larger ones, use smaller ones for better packaging or mix and match how they see fit.

Just a suggestion for a possible number for amount of tanks, i am thinking of 8. I think that might represent the upper limit for teams but for 987 that might be more like the median of their usual quantities.

Re: Pneumatic Restrictions & Improvments
 

This seems like a good compromise. If FRC could do some testing and give us a list of certified safe air tanks, teams would have plenty of notice and an unambiguous set of guidelines to work with.

As for general limits on the volume of storage, I would hope we wouldn't see those return. Prior to 2011, those volume limitations made it very difficult to use pneumatics without having an on-board compressor. With the weight and battery issues caused by a compressor, teams often skipped pneumatics entirely, with the exception of their shifters. Once the limits were removed we saw a huge increase in the usage of pneumatics, coupled with many unique designs which were previous infeasible or very difficult (254's jaw in 2011, 2056's shooter in 2013). There's been a definite evolution in design as a result of these more relaxed rules, and I'd hate to see us take a step backwards in terms of the functionality of robots.

Re: Pneumatic Restrictions & Improvments
 

I couldn't agree more about with respect to the evolution of design that the current state of the rules has allowed.

When it comes to limiting the allowable tanks, I see this as limiting a teams ability to research alternative storage tanks. There are a number of suppliers out there as well as custom options that would be more then acceptable under the current rules. As always, size and weight are a trade off in design. FRC558 has been looking into alternative tanks in the offseason, one potential source is the automotive aftermarket, since air suspension is a popular modification in the car world. I wish that there was a direct supply for an old KOP air tank, I believe we only received them in 2011 (Shown on pg. 11). There is always the old KOP tanks from Clippard.

Re: Pneumatic Restrictions & Improvments
 

A reasonable compromise might be something along the lines of plastic (or all tanks) shouldn't be capable of receiving direct impact from another robot. This is kind of a judgement call from the inspector, but it's really something teams should be doing anyway.

Re: Pneumatic Restrictions & Improvments
 

I'm really hesitant to agree to anything that makes more judgement calls for anyone in FRC.

However, I don't want to see plastic tanks go away and I don't want to see anyone wounded by shrapnel. I guess we just need some clear guidance on safe mounting practices.

Re: Pneumatic Restrictions & Improvments
 

Hopefully, if there is a future rule listing specific tanks that can be used, there will be a listed path towards getting additional tanks approved, similar to the pre-3/18 version of R31 in 2014, which had the blue box:
As for impact/mounting rules... While the GDC certainly could add them, IMO it's already covered under the safety rules - if a direct impact on something could result in shrapnel flying into the stands, then I would cite the safety rule in requiring a team to move it or shield it in some way. It's the same way inspectors reserved the right to ask teams to dry-fire a mechanism this year to ensure it was safe from spontaneous disassembly on the field, and how we've asked for various guards/protections on robots in past years.

Re: Pneumatic Restrictions & Improvments
 

I saw a large number robotics with plastic tanks mounted on the frame perimeter. Completely unguarded. We have dents in Al plate in similar places on our robot. The trouble with using the general safety rules is what is legal at one regional is not legal at another. It also requires the LRIs to use judgement with something they may not have much experience with. Much like shooter wheel guarding in 2013.

Re: Pneumatic Restrictions & Improvments
 

I think you are confused what a soft start valve does, it only works only when the system is being initially charged. Once it reaches the open transition pressure the main valve opens that value does not close until the system reaches close transition pressure. I have an smc on my desk that has an open/close transition pressures of 3/.5 bar and is rated 10m^3/h; much higher than a FRC team would need/use. Plus it is only about 1.5x1.5x2.5" in size and weights a few ounces.

The sole job of the valve is to pressurize the system slowly to prevent the large initial pressure surge that can cause a cylinder rapid to the end of its travel.

On the field when teams uses external compressors that have a a few tanks attached, they turn the ball valve and you can see this jump clear as day. This usually happens during the down between a match and its replay. I personally saw this two or three times this year alone.

On the the pressure transducer the sunx is nice because you can configure the limits of the dio which makes it a programmable pressure switch combined with a digital gauge and a 0-10V analog for pressure feedback. All this can be done in the same package instead of three. This was really more about convinence than anything else.

Re: Pneumatic Restrictions & Improvments
 

When I've inspected at QCR, the LRIs basically said to not trust shop compressors. In 2013, we did in fact catch a team hiding a compressor to fill their (12?) tanks. At one point, our LRI told us inspectors to go around the pits looking for shop compressors and have the teams remove them.

Re: Pneumatic Restrictions & Improvments
 

In 2014 at least, teams where not allowed off board storage tanks. Just the compressor. :]

Re: Pneumatic Restrictions & Improvments
 

I'm confused. Aren't you allowed to use a soft start valve already, since it's just another solenoid-operated valve?

Edit: Then again, since this should only apply to the case of an external compressor with external tanks, even a mechanical flow control would suffice.

-Karlis

Re: Pneumatic Restrictions & Improvments
 

Everyone,
So you all understand the process here, LRIs are not distrustful. We do answer to the teams who ask, "why is that team filling their robot with a shop compressor?" If you have a shop compressor in the pit and are using it often and quite noticeably just prior to your match, it gets noticed by those around you, those passing your pit and especially by those competing against you or with you in the next match. Why? Because teams have used shop compressors to fill their robot in the past, have bypassed the pressure relief valve and ignored safety rules and design criteria. There is no official rule against compressors from FIRST but there are event rules that prevent such items particularly for their current draw and acoustic output. As we move to district events, power will become a specific issue. Larger regional events pay dearly for power distribution to be installed and to be maintained. I believe events like Boilermaker still bring in generators to supply power to the pits and field. When you use high current (that is start currents) devices, you risk taking the pits around you, the entire pit or the entire event down. I have volunteered at events that suffered from power outages for this exact reason. It may be easier to ask you to remove the compressor than to continue to field questions and complaints throughout the weekend.
As to current ratings on compressor, do not confuse "full load amps" with start current. Such a compressor rating at 10 amps will often have start currents in excess of 25 amps. If you are at the end of a power feeder, every drop upstream of your pit will experience significant brownout or breaker trips. If you read your instruction manual closely, you will see a caveat that you should have a delay trip breaker installed on the line you use for the compressor to prevent tripping a standard breaker or to use on a high current output if possible.

Re: Pneumatic Restrictions & Improvments
 

What if that team is just filling because they are going to be testing in pit, or going to the practice field? The new Vair compressors are not robust, and limiting runtime on them is important to not enter a match preheated.

Re: Pneumatic Restrictions & Improvments
 

It doesn't matter when it's done... using a shop compressor to fill the robot bypasses safety mechanisms. It would be very easy to over pressurize the system when using a shop compressor (an no, the blow off valve isn't a guarantee for this... I've seen teams that went through 2 regionals, Champs, States, and then show up at an off-season in the fall who swear they never changed it, yet have their valve set at 150+PSI. Unfortunately, not everything is caught by inspectors), and in fact we've seen teams do just that, intentionally. When in the privacy of your own shop, teams can set their own safety rules... when at an event, I personally would ask you to be respectful of the safety of everyone around you and only operate your robot as listed by FIRST, which means using a legal compressor set up to charge your pneumatics every time, even when not going to the field. I would also probably ask the Lead Safety Adviser to chime in on the issue as well - It would probably fall under their purview more than the LRI's, unless the compressor is used before sending the robot to the field.

Re: Pneumatic Restrictions & Improvments
 

Then this brings up a whole can of worms that Tristan always likes to bring up. When and where do these rules apply? it currently isn't defined.

Also, what if the shop compressor isn't capable of reaching higher pressure than the robot? We have one that only hits 100 psi.

Re: Pneumatic Restrictions & Improvments
 

Adam,
It doesn't really matter to the observer, all that is seen is a team connecting a robot to a shop compressor or the illusion that a shop compressor is being used with the robot.
Think about this...
A team sees a compressor in use in a team's pit, they inform the head ref when they take the field. The head ref assumes that the team used a compressor to fill the robot in spite of having been inspected. That team may get lucky and the ref calls the LRI for assistance (if they can be found before the start of the match), or the ref may simply release (recommended first response) all stored air, or the head ref can disable your robot for a perceived violation or in worse case, red flag or worse is issued. I don't want that, you don't want that and the team doesn't want that. Remember that the ref doesn't know that you only intended to use the compressor to operate a stapler or that you fill your tanks with it. They do not know if your relief valve is correctly calibrated and operating or that you legally filled your tanks. They simply see a robot with air and a complaint from another team. It would seem to me that removing the compressor so it is no longer an issue prevents all of these real or perceived issues from occurring.

Re: Pneumatic Restrictions & Improvments
 

Wow. Another item on the list we have to be proactive about with people at events.

We currently have inspectors sign the form and note changes of our robot, and alliance partners robot's, ever since an unwarranted red card in 2013 cost us a regional. It's a bummer there is barely any space on the form for this.

The use of the air compressor is very nice, so we'll inform the LRI and Head Ref ahead of time that we understand the rules, and how we use the compressor.

It's crazy the burden is on teams to prevent unwarranted red cards... Guilty until proven innocent huh...?

Re: Pneumatic Restrictions & Improvments
 

What if you were on the other side of this? What if you saw a team filling their air tanks with a shop compressor, then watched them wheel it out to the field... when you complained to the head ref, you'd want him taking action, right?

It's not a question of assuming teams are intentionally trying to cheat or not... it's about trying to run an event that is both safe and fair to every team involved. It's not fair to team A to allow an illegal robot to compete against them, but it's also not fair to team B to red card them if they didn't really do anything... there's no way to ensure you're always making the right decision in every situation, as the information at hand may be the same. So you have to set up the rules and guidelines so you're consistent in the rulings, warn the teams ahead of time, and ask them to help you make the event a success for everyone.

Re: Pneumatic Restrictions & Improvments
 

In complete honesty, speaking as a coach and inspector for many years, I'd be fine losing to a team that didn't get a redcard for illegaly precharging IF that meant the # of teams getting unwarranted redcards was reduced. I'd also always discuss with the team directly before going to a head ref.

"Let the kids play" is my philosophy. Rules like this aren't nearly as damaging to opponents if they are broken than someone running with illegal motors, or illegal batteries (which are far easier to catch).

Before someone takes my words the wrong way, we ALWAYS charge w/ the onboard, legal compressor for match play.

What I'm against is the culture of teams being expected to avoid certain things because people think it might be illegal and the head ref red cards w/o discussing with all parties involved.

The retroactive red card rules is one of the most terrifying in the book, and really doesn't give students a better experience at all.

Re: Pneumatic Restrictions & Improvments
 

Agreed. The students want to win on a level field. If they lose they want to lose because a good team beat them, not a team that has an advantage, no matter how small or inconsequential. Inspections occur exclusively for this reason. Our (inspectors) responsibility is to level the field as much as is possible.

Re: Pneumatic Restrictions & Improvments
 

This sounds wrong. I imagine if there was an exclusive reason to inspect robots it would be for safety.

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I've got to agree. If a team wants to cheat in a competition for high school students and beat me, they could spend extra time working on their robot with almost no chance at getting caught. I'm not saying we should do everything based on the honor system (teams make honest mistakes sometimes), but having lots of these overkill rules leads to people making bad decisions, and lots of teams getting red cards.

I hate the atmosphere that we've had this year, where students and mentors honestly believe that inspectors and head refs are trying their hardest to give penalties and call teams out on subjective judgement calls, nonexistent rules, and where they "just can't remember what rule it is, but you broke it" as often as possible. This year, I've seen it all, from inspectors telling rookie teams (at the championship) misinformation, even after I walked up to the inspector, showed him the rule, and he agreed I was right.

With my experiences this year, it seems like inspectors/refs would much rather give out a bunch of red cards and prohibit things rather than to allow one or two robots on the field that may have charged their air tanks by shorting out the pressure switch for a few seconds or from a shop compressor.

I'll always do my best to make sure my team follows all the rules, but I wouldn't be too upset if my opponent fills his air tanks with a shop compressor. I'd be a lot less upset than if anybody got an incorrect red card/DQ.

Re: Pneumatic Restrictions & Improvments
 

magnets you couldn't be more wrong. We do not want to prevent teams from competing and we certainly do not want to issue red cards. (The LRI in the past was the messenger on delivering red cards that were not related to game play. I hated that task.) We, as inspectors and refs, want to see everyone play as much as they want. My direction to inspectors is to try every trick to get a team on the field. That might mean disabling an illegal mechanism or not using pneumatics for a match. If the inspector is working with the team we will work out an agreement with the head ref and FTA to allow the team to participate while they are working. The head ref, FTA and LRI act as a group to insure that the competition is both fair and a good experience for all. The LRI oversees everything in the pit and on the robot, the ref everything on the field and with the game and the FTA is the FIRST rep at the event and is tasked with making everything (especially the field) run smooth.
One of the biggest issues we face as volunteers is the fact that it is hard to get experienced volunteers in key positions. As I look at the inspector list, for instance, there are only a handful of people that have been LRIs for more than a few years. I am a rare exception with more than 10 years of regional and Championship LRI experience. With the lack of experience comes some times when mistakes are made or rules are incorrectly interpreted. It is for this reason that all key volunteers have a series of other people to turn to. All LRIs have my cell phone number and refs can get to the Aidan. The FTA has all of those numbers and has people that can answer calls at HQ every weekend, up to and including Frank. In addition to that, we follow the Q&A and most LRIs will keep an up to date listing of the Q&A and team updates at each event they work. Finally teams question me here on CD or privately throughout the season. I respond to all of those inquiries or point the team to the Q&A. It is still surprising that more teams do not come to CD for answers or don't even know about the wealth of information that is here.

Travis, safety is a subset of this as part of the inspection process. We would never ignore a safety issue to get a team on the field.

Re: Pneumatic Restrictions & Improvments
 

With all due respect Al, you are one LRI/Inspector out of many. I will say that I have encountered a number of inspectors this year going out of there way to fail robots during inspection (in one specific case, pressing down so hard on our bumpers that the noodles deformed well off the wood and failed inspection, our bumpers were properly constructed, fabric tight, and mounted at the correct height per the rules), as well as unjustifiable penalties at competition. While overall the general experience is good, a few bad eggs do leave a sour taste in my mouth, this year was less balanced then normal.

I truly feel that there are absolutely cases where there seems to personal "bad blood" between teams and volunteers.

In other news, this thread has gotten completely off topic. Pneumatics are one of my favorite things teach students about within robotics, and its a shame that the rules are not more well written and open. Perhaps its time to review this entire section of the manual as there are many artifacts from years past?

Re: Pneumatic Restrictions & Improvments
 

jw,
I am the Chief Robot Inspector so the LRI should give me a call if there is a concern over a special rule or unusual robot design. As to the penalties this year, refs still have to follow the game manual just like I/we must follow the robot rules. Personally, I do not like games that include a lot of penalties. I also like games that allow good human players to affect the outcome of a match. This past game was one of the better games for that interaction.

Re: Pneumatic Restrictions & Improvments
 

I will back up Al with the statement that he is available during the season. As an LRI I have called him more than once during the season. I have been involved with FIRST since 2002 and have been on a team since then. Every year I find challenging questions by the different things that teams come up with. Many teams push the rules to the limit which is good as long as they don't go past.

If you ever volunteer at an event as an inspector that I am LRI you will get the same speech I use at every event that I do. " If you have any doubt about something, come and ask me. If something looks out of place or strange, ask me. ". I want all decisions to be by the rules. If I am not sure I will comb the rules, go to the FTA or contact Al. I will also send inspectors to help teams that seem to be in trouble. Al has beaten into me that our goal as inspectors and LRI's is to get every team into every match if at all possible. I spend a lot of time helping fix problems that are found during inspection. I don't want my inspectors to point to something and say "Fix!" then walk away.

Remember folks that we as volunteers give of our time because we believe in FIRST, and the students. Seeing teams succeed is the only reward that we need. Some of us have left our team to do what we do because we feel that our teams are in good hands and that we can contribute some of our experience to other teams.

Do I agree with all of the rules? Nope but they are still the rules. Do I agree with the set speed limits, nope but they are the law. We must learn to compete within whatever constraints (rules) that are put on us and rise to the challenge.