pneumatics for 2006 competition?

[Joobacca]

Ok, so my team is in a constant debate whether or not to use pneumatics this year in FIRST's competition. Basically, the two sides are: 1) It's worth using pneumatics to benefit the robot either in a ball loading mechanism, some sort of break, or a way to extend portions of the robot 2) It's not worth the extra 15 pounds that will indefinitely be added to the robot if pneumatics is used.

What are your guys' takes on whether or not to use pneumatics, and for what purposes?

Also, I was wondering if there is a way to not use a compressor on our robot, but have an alternative way to fix our pneumatics if by chance the system were to fail.

Thanks and good luck!

[Rick TYler]

I can address part of this. If you are just using pneumatics in a really limited way you can just carry the air tank(s) and leave the compressor off the robot. There is no rule that the compressor has to be onboard to use pneumatics. We might do this for parts of the robot that unfold at the beginning of each match. If we go this way, we will charge the tanks and then disconnect the compressor.

[KenWittlief]

yep. Just make sure your system has no leaks. Sometimes your bot can sit on the field for...hmmm.. as long as an hour before the match starts (if you are in the first round of the day, and they queue you on the field during the opening ceremonies?

With no compresser, and the tanks pumped to max pressure you can get several actuations on a cylinder (depending on its size) before you run out of air.

[Joobacca]

yeah one of the ideas we had is to refill the tanks before a round, but ofcourse if there is a leak or the cylindars are too big, then the air would run out very quickly, and provide for a useless pneumatics system, and possibly a robot failure.

[KenWittlief]

teams have done no-compressor designs in the past.

it works well, esp if you only have one cylinder because there are only a few connections, and its easy to check for leaks (little bit of soapy water).

If it fits into your robot concept then go for it.

[Arkorobotics]

15 pounds is a lot, but if you have fewer motors then maybe you should consider the compressor. It's all up to your design. Just shooting ball with pneumatics takes some thinking.. believe me..

[Jared Russell]

Last year, Miss Daisy left off a compressor for weight reasons and instead used pre-charged tanks for gear shifting the AndyMark gearbox. We turned down the regulator to 25 psi or so (the lowest we could go and still shift reliably) and did some experimentation to figure out how many good shifts we could make.

The program then limited the automatic transmission to 35 or so gear shifts before locking into low for the rest of the round (in practice, seldom did we use more than 20).

In retrospect, we should have used servos, but we didn't have time to outfit them to work.

In general, the more you use pneumatics the more efficient it is in terms of weight - you only pay the price of the compressors, tanks, and regulators once, while additional cylinders can be quite light.

[DarkJedi613]

It all depends on if you need them or not. We've used pneumatics every year I've been on the team, although we are sponsored by Festo. Pneumatics do come in handy and are often worth the weight in my opinion. Though it does depend on the design.

Also the overhead for using pneumatics is more like 10 lbs. not 15. You can save a lot of weight by not using all the brass in the kit - there are better ways to set up the system.

[Bruce C.]

Originally Posted by KenWittlief

teams have done no-compressor designs in the past.

it works well, esp if you only have one cylinder because there are only a few connections, and its easy to check for leaks (little bit of soapy water).

If it fits into your robot concept then go for it.

It's also handy to have the compressor connnected to a battery (safely, of course, with fusing and appropriate wire size) mounted on your transport cart. That way you can top off the air tanks while in the staging lanes right up to the last minute.

We also toyed with the idea of mounting an RV battery running a dc => ac inverter and 6A battery charger on our cart. Then we could charge our robot battery on the cart in the staging lane right up to time to take it off the cart. (Of course, we had a pretty big transport cart. )

[KenWittlief]

keeping the air tank topped off until the last minute before a match makes sense, because your pneumatics might be leaking a little bit. Putting a shutoff valve right after the tank is the best way to keep the tank full till the last minute.

but your battery should not be 'leaking charge' while its on your robot, esp unplugged. Having a big RV battery in your cart could be somewhat dangerous: they are full of acid, and if it got shorted by accident then Yikes!

[Bruce C.]

Originally Posted by KenWittlief

but your battery should not be 'leaking charge' while its on your robot, esp unplugged. Having a big RV battery in your cart could be somewhat dangerous: they are full of acid, and if it got shorted by accident then Yikes!

True, the battery won't be "leaking charge" , but sometimes, with fast match schedules and limited batteries, the battery doesn't get fully charged in the pit between matches. It's nice to be pushing that charge in until it's fully "topped off."

And certainly, an RV battery will have to be mounted safely. I would put it in a plastic RV battery box, use proper fusing, wire size, and have all terminals covered or well insulated to prevent shorts. A sealed LA battery properly mounted in a protected location on a cart should be no more dangerous than the FIRST battery. Now, as I said, it takes a pretty large transport cart to pull this off. Kinda like the ones I've seen at past Nats with the 26 bazillion watt lights and stereo systems with the six foot speakers!