Re: Filling Robot Pneumatic Systems
 

Why do you care if you can disable the compressor via the cRio?

The danger is not the compressor, it's the air in the tanks. Control via the cRio does not change that.

Re: Filling Robot Pneumatic Systems
 

All the inspectors are doing in their checks is testing that a) the 125psi relief valve is functioning properly, b) that the nason switch is shutting off the compressor (under control of the cRIO) at 115-120psi, c) that the working components are all downstream of a 60psi reg.

I'm not suggesting that any of these tests be abandoned. Just changed such that as long as I prove the reliefs are working and the compressor shuts off when it should (below 120), it doesn't matter what controls I used to achieve it.

Re: Filling Robot Pneumatic Systems
 

Right idea but a little off in the reasoning.

This is as simple as the inspectors and safety personnel needing to be ensured of safety by the teams.

I as an educated engineer can make several simple systems that will work for off board pnuematics charging, however it becomes incumbent on me to prove this is safe to the event staff. If everyone has a different system how do I as an inspector or safety personnel at the event know that your system is properly designed and tested? How do I know if you're not using my pressure transducer that you aren't overpressuring your system?

It is easier for FIRST to legislate the design of the system so that they know it is safe because the design is tested and proven.

Also when you consider off board compressors please think about this, Do you want to be sweatting a slow leak in the system when you're queued on the field through opening ceremonies or a long Dean speach? You may regret this decision...

Re: Filling Robot Pneumatic Systems
 

Everyone,
The basis of all this discussion comes down to one very simple rule...
R34
Non-electrical sources of energy used by the ROBOT, (i.e., stored at the start of a MATCH), shall come only from the following sources:
A. compressed air stored in the pneumatic system that is legal per R79 and R80,
B. a change in the altitude of the ROBOT center of gravity, and
C. storage achieved by deformation of ROBOT parts.

Referenced in the preamble...
"In addition, another intent of these rules is to have all energy sources and active actuation systems on the ROBOT (e.g. batteries, compressors, motors, servos, cylinders, and their controllers) drawn from a well-defined set of options. This is to ensure that all Teams have access to the same actuation resources,and to ensure that the Inspectors are able to accurately assess the legality of a given part."

Every team believes and expects that the inspectors are insuring that this rule is met. To assist us with that task the remaining pneumatic rules are in place.
If you think that teams would never bypass the rules or do something unsafe (intentional or unintentional), I suggest you spend a weekend as an inspector. Every bad scenario that you can think of, we have seen. Including the team who had a student holding the power cord for the shop compressor and would pull the power when he thought the system was sufficiently charged.

Re: Filling Robot Pneumatic Systems
 

When you're hooked up this way, is there any easy way to release stored air? It sounds like your manual vent plug isn't accessibly as it's connected to your off-board storage. I also read the rules as implying that off-board storage isn't allowed - the diagrams for off-board compressors explicitly show what is allowed off-board in those situations, and storage is not included off-board. Why would storage be allowed off-board for an on-board compressor, but not be allowed off-board for an off-board compressor?

Re: Filling Robot Pneumatic Systems
 

Al,

Is there any official way to suggest a rule change for the future? The rule is not ambiguous at all now, so it dosn't seem like the Q and A is the right place, but neither is CD.

Re: Filling Robot Pneumatic Systems
 

Al,

I know you and I have hashed this out in the past.

R79 states I must use one and only one compressor, with flow rate not exceeding 1.05cfm. While I would argue that since I can change my battery after precharging and before a MATCH, the compressor used to pre-charge my tanks is irrelevant in terms of competitive advantage, I could see an argument that using some high-flow compressor gives me an unfair advantage because I don't need to wait around while my compressor charges, even in the pits. I don't really take issue with R79. So I have to use a Viair C90 or old KOP Thomas compressor, or something very similar, no big deal.

R80 is the one that I am taking issue with. I disagree that its restriction that I must use my ROBOT's control system to control my compressor has any competitive or safety based reason for existence -- provided that I'm still proving that the reliefs and system-full shutoff are working properly. If the safeties are the same, this restriction is completely arbitrary and unnecessarily stifles creativity. Competitively, its the 120psi air that gives me a competitive advantage. Its source, and how its source is controlled are irrelevant. Safety wise, I'm recommending the checks be kept, so its still safe.

Re: Filling Robot Pneumatic Systems
 

Andrew,
While people may not post, that does not mean they are not reading and lurking here on a regular basis. I would bet that the GDC and HQ have read your posts and understand your feelings. Posting the question on the Q&A will give you a definitive answer from GDC.

Re: Filling Robot Pneumatic Systems
 

Tom,
Since it looks like you are going the Centerline for week 1 where I will be the LRI I would like to tell you that I see no provisions in the rules for off board storage of air, just provisions for an off board compressor. Additionally, the illustrations with R85 & R86 explicitly show the air storage on board the robot. Unless there is a rule update, relevant Q&A or specific instructions from the Chief FRC Inspector, I do not see off board air storage as legal. It can absolutely be done safely, but I don't think it is legal at this time. Feel free to make a counter argument.

MK

Re: Filling Robot Pneumatic Systems
 

I also don't see any rules or Q&A that explicitly disallow this setup either. It's a grey area and definitely warrants a Q&A.

Re: Filling Robot Pneumatic Systems
 

I understand that as written, this is a grey area within the rule. The grey area was removed at LRI training this year (and is consistent with prior years). Conveniently, the same guidance that was provided at training was captured in the recent FRC Ask an Expert webcast on Robot Inspection located at
https://www.youtube.com/watch?v=jW_X...e_gdata_player
It is a lengthy video. The portion relevant to this conversation is at 35:10. I realize that this is not an actual rule, but I think it is only fair for the teams to know what guidance was given to all the LRI's. For this that are not aware, this training takes place at FIRST HQ with members of the GDC in the room. Consequentially, there isn't much room for me to have an opinion on this issue.

Fortunately it is only halfway through the build season and there is plenty of time to get a Q&A submitted.

MK

Re: Filling Robot Pneumatic Systems
 

Spoiler Alert! History lesson coming....
When FRC first allowed compressed air to be used on robots, (no it was not always the case) the rules were written for very specific implementations. On board compressor and a maximum number of metal storage tanks only. Then one day Bill Beatty of the World Famous Hammond Team asked if they could take the compressor off the robot to add weight for another device. The GDC at the time decided to agree with Mr. Bill. These were the provisions, moving the compressor off board could buy the team nothing but the weight savings in return for the risky choice to have no additional air for the match. That is the quid pro quo, weight for risk. We have added a few items to that original list, as listed in R86. So regardless of how you look at this, consider that the the compressor is on board and all rules apply. If you move the compressor off board, all the rules still apply but you are taking the risk that you run out of air.