Reversed Pneumatics

I just want to make sure that we are not breaking any rules, but my team wants to use 2 pneumatic cylinders in a way where the pistons would start extended at the begininng of a match to comply with frame perimeter rules. I could not find anything explicitly against it and wanted to make sure I was not missing something important.

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This should be fine, as long as the robot is completely within its frame perimeter.

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This isn’t prohibited by any rules, so you can do it. As long as the robot starts completely within the frame perimeter, it doesn’t matter what state any of your mechanisms are in.


The key is “starts”… The robot must stay in the STARTING CONFIGURATION (completely within its FRAME PERIMETER) until the start of auto. As long as it will do this after being powered up, but not yet enabled you are good to go. As mentioned mechanisms can be in any position within their travel range, as long as they are inside the FP.

For example, we have an over the BUMPER intake mechanism. Our STARTING CONFIG is with the mechanism lifted almost straight up to be within the FP. We have a “kickstand” bar that keeps the intake in this position. Once enabled at start of auto, we lift the intake slightly and the kickstand disengages and we can drop the intake to operating position outside of the BUMPER.

Fully legal and is possible using a single solenoid rather than a double solenoid. Just have to make sure you tube the pistons correctly

If you’re depending on pneumatics to hold your robot inside the frame perimeter before the match, be extra vigilant for air leaks, and that you have your vent plug fully closed each match.

I wonder what would happen, if you were to set up the robot such that it was within the frame perimeter, but due to an extended match start delay (we’ve experienced robots sitting on the field for upwards of one hour while they’re dealing with FMS issues or whatever), the air pressure drops and the robot is no longer within its frame perimeter.

If you’re waiting for an hour, then ask the FTA for permission to recharge your tanks before the match finally does start.
But do so early, ahead of when you actually need it, not as they are finally clearing the field for a late match start. If the FTA knows ahead of time they can plan for it and tell you when to charge up.

Of course, fix leaky pneumatics. A charged system properly sealed should be able to hold pressure overnight.

These are my concerns with such a system, and why I like simple mechanical solutions. If you have a leak, you are relying on being allowed to go recharge it. Depends on the FTA, and how the event is going, as to whether you will get granted the time to recharge it. Plus it relies on a not leaky system. We have a fair bit of experience with pneumatics, and (I believe) tend to build fairly robust robots paying attention to things like strain relief and line routing. However, we have also had some issues with leaks, after enthusiastic match play. To me, it is another system to have to worry about, where failure may get us disabled (G1) especially if we have a repeat occurrence at an event.

Agree 100%.

But you also need to be ready for the quick turn-around scenario where you may not have time to pressurize. This can be especially problematic if you are making a repair between matches and are pressed for time to get your robot on the field. If you only need 1 or 2 tanks, the recharge time is quick, but not zero. If you need a lot of tanks to have enough air for some heavy usage, the re-charge time can be multiple minutes. G1 comes into play if it is not a “quick fix”. Tethering and running the compressor while the robot is on the cart rolling through the pits on the way to queue or while loading onto the field is not that much fun.

This issue might also be exacerbated by dumping your air for repairs, or at the request of field staff after matches. At the 2019 Arkansas Regional, an FTA or ref would ask us to open our release valve after every single match. This was something I had never encountered before and I don’t believe it’s actually in the rulebook but it didn’t inconvenience us enough to push the issue with the head referee. @GeeTwo, I know you volunteered at that event. Could you possibly provide insight into this? I don’t think it’s a common practice as we were never asked to dump our air after matches at any other event, including Champs. The staff at the same event also wouldn’t allow us to push our robot onto the field - they required us to carry it - even though it was faster and safer to push the robot over the gate and onto the HAB. This was also only an issue in Little Rock.

I apologize for derailing the thread but I think it’s important to be prepared for anything and I’d like to know if these calls were by the book and something OP and others should be prepared for or just overzealous officiating.

It’s not, but they may be trying to be safe and de-energize everything. Turning the robot off is a relatively common ask but dumping air isn’t. Your best move is to ask the rationale.

Understood. Thankfully it was never a huge issue for us (we had much, and I mean MUCH bigger fish to fry at that particular event), but if it’s ever an issue again I’ll put forward to ask the head ref about it. I’d like to add that besides that one point, the Arkansas Regional is run exceptionally well and my former team was ecstatic to get the opportunity to return this year. I don’t mean to seem like I’m bashing anyone at all.

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No, I didn’t spend much time in the arena as an inspector. From what you said, it sounded like it was coming from the FTA rather than the LRI. I’ll be there again this year; I’ll try to remember to ask about it at one of the inspectors’ meetings.

Much appreciated. Like I said, it was never a huge issue, just an anomaly I was curious about.

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