Do we have to use a compressor.

[Craig1989]

We are considering using a very small pneumatic piston; however, it would only be used at the end of the match to release the ramp. My question is can we use a simpler mechaism (just cylinder, tanks, and necessary valves) or must we include all the pneumatic components?

[Al Skierkiewicz]

Craig,
You can use a servo attached to a wire locking mechanism to hold up the ramp or simply use the servo arms as a latch. Servos have a variety of attachements that you might be able to use and it weighs less than an pnumatic actuator.

[Mike Starke]

You can also have an outboard compressor, meaning that before each match, you fill up your tanks, so you don't have to have compressor on board. 340 did that at Nats last year. Yeah, its nice, but it does become a pain when you have to do it every match, it just adds one more thing you have to check. So I would look into what Al said about using a servo.

[Doug G]

Last year we had to lose some weight in Portland, we chose to lose the pump since all we did was use it for shifting. Be forewarned though you still need to follow all pnuematic rules even if you're precharging tanks before each match. You still need to regulate your working system to 60 psi and use the gauges and relief valve.

In order for us to pass inspection last year, our off board compressor had to still be wired correctly to a battery through the 120 amp fuse and separate 20 Amp fuse and use appropriate wire gauges and such even though it wasn't on the robot (it was on our cart). But once that was done it worked very nicely and is the safe and convienent way to go!!

[T3_1565]

we had to drop our compressor too 2 years ago. Its not a must, but depending on what your doing, it's a pain to run out of air lol

[JBotAlan]

Originally Posted by Doug G

In order for us to pass inspection last year, our off board compressor had to still be wired correctly to a battery through the 120 amp fuse and separate 20 Amp fuse and use appropriate wire gauges and such even though it wasn't on the robot (it was on our cart).

We had the same issue, and it sparked some serious discussion. What we had was fused and all the connections were secure, but the rules still required that we connect the pump through a Spike. Now, we lawyered the rule and ran the current of one of the leads through a Spike. That got us past inspection. This year the rules are clearer, <R101> tells us:

<R101> The compressor may be mounted on the ROBOT, or it may be left off the ROBOT and used to pre-charge compressed air in the storage tanks prior to bringing the ROBOT onto the playing field. Off-board compressors must be controlled and powered by the ROBOT. The only difference between an on- and off-board compressor is that the off-board compressor is physically removed from the ROBOT. Note: the intent of this rule is to permit teams to take advantage of the weight savings associated with keeping the compressor off-board. But using the compressor off-board of the ROBOT does NOT permit non-compliance with any other applicable rules.

So, we will probably make some kind of 5 (ish) wire connector to attach the Spike and signal cable to the robot. It is a safety issue, though--the robot won't trigger the compressor if it is disabled, so it must be enabled and powered on with the controls tethered (triple ) to fill the tanks. I will talk to my mentor about submitting this to the QnA to see if they will revise the rules to make filling up more safe.

JBot

[EricRobodox]

We did this last year, an off board compressor, basically get all your old batteries, a KOP compressor, a relay and create a simple board that you take to competitions. This is completely legal. We did this last year as i said, but we also showed like 3 other teams how to do this, and helped 696 make one in Arizona i think it was, maybe LA, cant remeber. But my friend and i built it for the team, it was definetly a good choice because the only weight of pneumatics were the pistons and the valves (solenoids, regulator, gauges) basically. Very light and not too much harder to manage. If you want to be even better, add to the compressor a bunch of air tanks, that way you dont have to turn the compressor on with the robot for a long time, you can just have the stored air transfered into the robot between matches.


Note: If you want to build one, do follow exactly the BOM to make it as i said, i mentioned just a lazy parts list for it, there are a few more electronics involved. lol.

[Al Skierkiewicz]

Originally Posted by EricRobodox

We did this last year, an off board compressor, basically get all your old batteries, a KOP compressor, a relay and create a simple board that you take to competitions. This is completely legal. ...If you want to be even better, add to the compressor a bunch of air tanks, that way you dont have to turn the compressor on with the robot for a long time, you can just have the stored air transfered into the robot between matches.

Eric and everyone, this method is not legal this year and was doubtful last year. Please check the rulebook as outlined above. The compressor needs to be under RC control and will be checked during inspection.

[steveg]

Originally Posted by Al Skierkiewicz

Eric and everyone, this method is not legal this year and was doubtful last year. Please check the rulebook as outlined above. The compressor needs to be under RC control and will be checked during inspection.

It wasn't really legal last year. That was the method we were attempting, and in Boston it was deemed illegal. We talked to some Innovation First guys, and decided that to make it legal, we wired a spike to a switch, and had him with us telling the judge it was OK during reinspection.


...


The next team update clearifed that rule, and stated that the compressor spike needed to be controlled by the RC, probably because of me.

[Daniel_LaFleur]

Originally Posted by EricRobodox

We did this last year, an off board compressor, basically get all your old batteries, a KOP compressor, a relay and create a simple board that you take to competitions. This is completely legal. We did this last year as i said, but we also showed like 3 other teams how to do this, and helped 696 make one in Arizona i think it was, maybe LA, cant remeber. But my friend and i built it for the team, it was definetly a good choice because the only weight of pneumatics were the pistons and the valves (solenoids, regulator, gauges) basically. Very light and not too much harder to manage. If you want to be even better, add to the compressor a bunch of air tanks, that way you dont have to turn the compressor on with the robot for a long time, you can just have the stored air transfered into the robot between matches.


Note: If you want to build one, do follow exactly the BOM to make it as i said, i mentioned just a lazy parts list for it, there are a few more electronics involved. lol.

Originally Posted by rules

<R101> The compressor may be mounted on the ROBOT, or it may be left off the ROBOT and used to pre-charge compressed air in the storage tanks prior to bringing the ROBOT onto the playing field. Off-board compressors must be controlled and powered by the ROBOT. The only difference between an on- and off-board compressor is that the off-board compressor is physically removed from the ROBOT. Note: the intent of this rule is to permit teams to take advantage of the weight savings associated with keeping the compressor off-board. But using the compressor off-board of the ROBOT does NOT permit non-compliance with any other applicable rules.

This is not legal this year. Off board compressors must still be controlled and powered by the robot.

[EricH]

Originally Posted by Al Skierkiewicz

You can use a servo attached to a wire locking mechanism to hold up the ramp or simply use the servo arms as a latch. Servos have a variety of attachements that you might be able to use and it weighs less than an pnumatic actuator.

We did that for our rear wedge in 2005. Cut a slot in lexan, put a servo in the back panel of the robot's tower, and put a double-ended arm type of attachment on the servo. Never had a problem with the release, but pulling the thing back up was another matter. (Also just used the servo as the latch--won't work as well here.)

The thing is that whatever you use needs to be strong enough to hold the ramp up throughout the match, when you are taking hits, making hard turns, and generally applying a lot of force to the attachment. Plan for that. If you can do it with a servo, great. If not, a small cylinder with just a tank and regulator and such is just fine.