Pneumatic Restrictions & Improvments

[apples000]

Originally Posted by magnets

First of all, pneumatics restrictions were lessened by a lot this year. The CV of the valve restriction was removed.

The reason the GDC limits CV is for safety. If we had unlimited CV, and someone were to put their head against a medium to large size pneumatic cylinder, and it is accidentally actuated, the person would die.

Very true.

This year, we were playing around with a pneumatic launcher, and we wanted to try it with shop air. Strangely, no air was coming from the valve, and after closing all the other valves in the room (it shuts off the compressor if it detects a leak) so I went to go to the maintenance room to check on the big compressor. It turns out the room's dump valve had a faulty contact, and when I opened up the electrical panel, the valve opened, pressurizing the cylinder very, very quickly. The cylinder and its bracket went flying across the table, both fittings were torn/snapped off. It left a sizeable dent in the sheet steel counter, and chipped off part of our CNC's safety shield!

[DampRobot]

Let us charge with offboard air compressors, even if we have one onboard.

If it's made legal for everyone, it's no longer a competitive advantage, and there are ways to let it happen safely. I'd argue it's much safer to go into the match with a cool compressor than a hot one which can melt tubing or drag on battery voltage.

[Mk.32]

Originally Posted by DampRobot

Let us charge with offboard air compressors, even if we have one onboard.

If it's made legal for everyone, it's no longer a competitive advantage, and there are ways to let it happen safely. I'd argue it's much safer to go into the match with a cool compressor than a hot one which can melt tubing or drag on battery voltage.

As a robot 2014 inspector, this can be legal. You just have to power it from the robot. With either an 2nd spike or just unplugging the off board temporary. I know 987 actually had two off board compressors they switch between to make sure they never over heated.

Now I understand you probably mean just plugged in a off board into a battery, or using a shop air compressor. But safety concerns I would guess, have first to ban them and we have no power over that. Again rules many change in 2015, but doubt they would change this one.

[Gregor]

Originally Posted by Mk.32

As a robot 2014 inspector, this can be legal. You just have to power it from the robot. With either an 2nd spike or just unplugging the off board temporary. I know 987 actually had two off board compressors they switch between to make sure they never over heated.

R79 is pretty clear stating that you cannot. "One and only one compressor."

Originally Posted by 2014 Manual

R79
Compressed air on the ROBOT must be provided by one and only one compressor. Compressor specifications may not exceed nominal 12VDC, 1.05 cfm flow rate.

[Mk.32]

Originally Posted by Gregor

R79 is pretty clear stating that you cannot. "One and only one compressor."

We had this debate .... and I think it was on QA too, one and one compressor = one running at a time. So you can have two in the pits/around, but you can't use them both at the same time (aka to charge air faster).

[Jon Stratis]

Originally Posted by Mk.32

We had this debate .... and I think it was on QA too, one and one compressor = one running at a time. So you can have two in the pits/around, but you can't use them both at the same time (aka to charge air faster).

I just checked, it wasn't specifically asked on the Q&A this past year. Regardless, R79 is very clear - your robot can only have one source of compressed air. Filling it with an off board compressor then using a different on board compressor during the match is two sources. If you dump pressure before the match, your fine... And as an LRI, that's what I'll do if I see a team charging with an off board compressor while having one on board.

[JB987]

We didn't have an on board compressor on our robot. As stated in previous post, we had two off board compressors and only used ONE at any given time.

[JohnFogarty]

Don't you just love the English language and how it can be vague and very specific at the same time?

I don't understand the whole issue of using an off-board compressor to store air into the robot's system if the off board compressor can easily be connected to the robot's control system (temporarily in place of the on-board compressor) so the the robot can control the air input for a pre-match charge. This way the on-board compressor won't heat up because it isn't being used pre-match.

What I'm seeing a lot of people say is that people used multiple compressors at one time to charge a system. I can see this being a bit of an isssue, but not the situation I mentioned above, because in the senario I provided there is only one compressor/air source connected to the robot's system at any given moment.

[Mk.32]

Originally Posted by Jon Stratis

I just checked, it wasn't specifically asked on the Q&A this past year. Regardless, R79 is very clear - your robot can only have one source of compressed air. Filling it with an off board compressor then using a different on board compressor during the match is two sources. If you dump pressure before the match, your fine... And as an LRI, that's what I'll do if I see a team charging with an off board compressor while having one on board.

My apologies for mis-understanding and not being clear.
What I meant was was switching between two off board compressors, to make sure none of the over heated but only using one actively at a time. While having no on board. My team had to do this due to the enormous (5gal) tank we had and we had deliberate over the "one and only one" rule.

But if a team were to have a on board and then disconnect it, and use an off board properly wired into the robot to pre-fill before a match so the on board stays cool during the match; I would think this is legal? Since air is only being provided by one compressor at a time that is wired legally.

[Tungrus]

Originally Posted by Mk.32

But if a team were to have a on board and then disconnect it, and use an off board properly wired into the robot to pre-fill before a match so the on board stays cool during the match; I would think this is legal? Since air is only being provided by one compressor at a time that is wired legally.

This is legal, there was a clarification early this season, if I remember it correctly the requirement is that the compressor must be operated using robot control system.

Couple of years back I have seen teams using a off-board compressor directly plugged into battery and charging.. this is illegal.

The key thing is there are only so many safety inspectors who can check all on-board and off-board pneumatic systems. It isn't easy for these inspectors to twist and bend in every direction to access the on-board system. If teams are allowed for off-board control system (or worse no control system) and off-board compressor, now the inspectors will have to inspect these systems that may be on the cart or somewhere else. God bless them, they do a good job to keep everyone safe.

[Mark McLeod]

Originally Posted by Mk.32

But if a team were to have a on board and then disconnect it, and use an off board properly wired into the robot to pre-fill before a match so the on board stays cool during the match; I would think this is legal? Since air is only being provided by one compressor at a time that is wired legally.

That would still be an obvious violation of R79.
If the compressed air is generated and mixed from more than a single compressor, then rule R79 is violated.

[Jon Stratis]

Originally Posted by Mk.32

My apologies for mis-understanding and not being clear.
What I meant was was switching between two off board compressors, to make sure none of the over heated but only using one actively at a time. While having no on board. My team had to do this due to the enormous (5gal) tank we had and we had deliberate over the "one and only one" rule.

But if a team were to have a on board and then disconnect it, and use an off board properly wired into the robot to pre-fill before a match so the on board stays cool during the match; I would think this is legal? Since air is only being provided by one compressor at a time that is wired legally.

R79 did not include any wording indicating "at a time".

R79

Compressed air on the ROBOT must be provided by one and only one compressor. Compressor specifications may not exceed nominal 12VDC, 1.05 cfm flow rate.

The wording of the rule is straight forward and strict - all of the compressed air in use on the robot during a match must come from one and only one compressor. You can't mix sources between on-board and off-board, or charge halfway with one compressor and finish it off with another.

Personally, I think this rule could stand to be expanded a little to allow more variation in how pneumatic systems are charged, but as it's written it's very strict. Thinking about the reasoning behind it, I can see safety being one reason, fair play being another (not every team can afford to buy 2+ compressors just to charge their system), and good design being a third (If you can't charge your system without overheating your compressor, then you may want to re-think the design of the system and the constraints you have to work within, rather than just "throw more compressors at it" - not intended to be directed at you in particular, alternating compressors from one match to the other so they have time to cool down is certainly a valid engineering solution).

[notmattlythgoe]

There are ways of keeping a compressor from over heating. We had some over heating problems on our practice bot prior to going to our first competition, mainly because we had a lot of pneumatic components on our robot this year. What we did was place a fan on the robot blowing across the heat sink and the compressor never got hot to the touch after that.

[JB987]

Originally Posted by Jon Stratis

R79 did not include any wording indicating "at a time".



The wording of the rule is straight forward and strict - all of the compressed air in use on the robot during a match must come from one and only one compressor. You can't mix sources between on-board and off-board, or charge halfway with one compressor and finish it off with another.

Personally, I think this rule could stand to be expanded a little to allow more variation in how pneumatic systems are charged, but as it's written it's very strict. Thinking about the reasoning behind it, I can see safety being one reason, fair play being another (not every team can afford to buy 2+ compressors just to charge their system), and good design being a third (If you can't charge your system without overheating your compressor, then you may want to re-think the design of the system and the constraints you have to work within, rather than just "throw more compressors at it" - not intended to be directed at you in particular, alternating compressors from one match to the other so they have time to cool down is certainly a valid engineering solution).

And this is exactly what we did. There was simply two independently controlled compressors mounted on a small platform off board and in case there was a rapid turn around issue in eliminations (or a broken compressor) we were prepared to use the second one as a backup should the primary one be overheated. Per the reasoning demonstrated in some of these posts, anyone who has a broken compressor and replaces it would be breaking the r79 rule if they used the replacement to add air to the system. Head inspectors at two regionals agreed we were compliant. By the way, as I recall we never had to use the second compressor...and we eventually substituted for a Firestone heavy duty cycle ( also legal) compressor that worked fantastic at Champs.

[Andrew Schreiber]

Originally Posted by Mk.32

We had this debate .... and I think it was on QA too, one and one compressor = one running at a time. So you can have two in the pits/around, but you can't use them both at the same time (aka to charge air faster).

Then this needs to be communicated to ALL LRIs. That rule was cited (in an incredibly rude manner) by the LRI at one of our events as the reason to remove a secondary compressor we used to power tools. He ignored any proof that we couldn't even connect the compressor to the robot (didn't have proper fittings) and was utterly unable to provide any clarification on the rule when asked. He also seemed to think that any spares we had needed to be outside the venue.