No Pneumatics? [Archive]

artdutra04

12-04-2013, 16:25

Adding a pneumatic system to a robot now is no longer the weight penalty it once was, especially since the VIAIR compressor and plastic air tanks are a fraction of the weight of their predecessors.

They have some other nice aspects like having the ability to be stalled forever and to allow "after the buzzer" operation, both of which aided a lot of teams this year for their 10pt hanging mechanisms.

mman1506

12-04-2013, 17:36

Pneumatics also puts out the most power (speed/torque) for there weight

Tow

12-04-2013, 18:00

Actually our team has never used pbeumatics since it's rookie team, but is mayoritarily because we actually don't know how to use them well

pmangels17

12-04-2013, 18:01

For us, our transmissions use 3 different air cylinders. One for PTO (power take off), on for Hi-Lo Shifting, and one for our Pneumatic Brake. Some teams use servos to shift, but they are fidgetey. We are going to try a servo powered brake, results to come eventually. Many teams have had success with window motors for shifting multiple gearboxes at onc, but we prefer pneumatics, and with the size constraint it makes life easier. Pistons are also more accurate on many two-position mechanisms, whereas the same mechanism with a motor would require a gearbox and limit switches/potentiometers/encoders.

Pneumatics are pretty simple, as long as you don't try to put a 1/4" hose into a 6mm fitting :P

cjl2625

12-04-2013, 21:27

We've had problems with pneumatics in the past, so now we pretty much just stay away from it altogether.

CENTURION

12-04-2013, 21:41

We've had problems with pneumatics in the past, so now we pretty much just stay away from it altogether.

I've heard sayings to this effect before in my own team. We had a pneumatic system in our 2010 robot that had leaks and other sorts of issues, and that lead many students to swear to never use pneumatics again. One even said that we should make it an official team rule: No Pneumatics.

But those students graduated, and the newer students this year threw a pneumatic system in the robot. And it works just fine ;)

I guess what I'm saying (And I really do mean it in the nicest way possible) is;

It's probably not the pneumatic's fault.

mman1506

12-04-2013, 21:43

The only pneumatics part we really have had a problem with is the old festo KOP solenoids. The SMC ones work great.

Jacob.B

12-04-2013, 22:04

The HOT team doesn't use pnuematics and haven't for a while. This year they have Vex Ball shifters that they can't shift, YET! :D

Andrew Schreiber

12-04-2013, 22:04

Wait... you can build a rowboat without pneumatics? Ooops.

Andrew Lawrence

12-04-2013, 22:39

We didn't use pneumatics last year or this year. No major situations where we said "darn, we wish we had pneumatics for this". That being said, we may use them in our robot redesign for some Ultimate Ascent offseasons for shifting, feeding, and climbing.

Billfred

12-04-2013, 23:10

2815 has used pneumatics two years out of five, 2010 (shifting) and 2013 (shifting and frisbee firing).

2815 has missed Championship two years out of five, 2010 and 2013.

Correlation vs. causation aside, it is something that gives me a little pause before immediately jumping to them.

Ernst

12-04-2013, 23:30

1732 has been using pneumatics for at least the past 4 seasons. We found out this season that a lot of our leaks were coming from off-square cuts on the ends of tubes. This caused them, when plugged into a fitting, to not form a perfect seal. We solved that problem this year with a pneumatic tubing cutter (http://www.amazon.com/Compact-Cutter-Thermoplastic-Tubing-TC-01/dp/B007CJLG4Q/ref=sr_1_1?ie=UTF8&qid=1365823530&sr=8-1&keywords=pneumatic+tube+cutter) that makes it difficult to make a bad cut.

CENTURION

12-04-2013, 23:55

ice.berg

13-04-2013, 00:15

Well before 2012 we didn't use pneumatics at all. But with our octomecanum system last year we were forced to use it. This year we use pneumatics for a whole ton of stuff: floor intake, octomec. system, and disc feeding. But the nicest part about it is sensors, or lack there of. In 2011 we had a whole variety of limit switches that would always break. Now with the pneumatics the systems can be made much simpler and more reliable.

The key is:
-Follow the rulebook the first time. Make sure all your fittings tubing etc. is all legal and COTS
-Do the soapy water check, spray down all your components while under pressure with soapy water and check for leaks otherwise they will be the death of your robot
-Off-board compressor with plastic tanks, we roughly measured that we could put 6~7 tanks on our robot before having an on-board compressor would be worth it
-Do the calculations for your actuators, make sure you arent overdoing it and using the minimum amount of air needed in order to actuate it under load.

jar24

14-04-2013, 00:03

my team generally uses them every year but we ruled it out because of the weight that it adds, the space they take, and how fast it kills battery's and we did the best in our teams history.

Zuelu562

14-04-2013, 07:40

On 562, my team as a student, we used pneumatics every year except for Lunacy. We had a couple successful robots, no regional titles, but those robots were very strong.

Since joining 3623 (and even before, during their rookie year) we have not used pneumatics. We were pondering whether to use them this year to hang, but considering our design and the weight penalty comparatively (Our robot was 89 pounds, IIRC) made using pneumatics just for one system impractical. We had no problems without it.

Think about using it year to year, but make sure you know how to use it and set it up correctly. I'd never be opposed, but think about usage.

Adam Freeman

14-04-2013, 08:41

We have not used pneumatics on a robot since 2004.

It's not that we are opposed to using them, we just typically haven't found the tipping point of enough mechanisms that would need that type of actuation to make the investment in weight, packaging, etc...to put a pneumatic system on one of our machines.

With not using them for so long, I think if we are seeing mechanisms differently such that we think a motor and gearbox would work better. I'm sure if we started using pneumatics, we would find plenty of uses for them.

For this year, we were planning on having them on the robot but ran out of space for almost everything. We scrambled to even find room for the battery and cRIO, so even a "passive" pneumatic system without a compressor was pretty much impossible for us. Corner climbing systems take up a lot of space.

-Adam

MrForbes

14-04-2013, 09:38

We've used pneumatics every year (starting 2006) except 2009 for Lunacy. Pneumatics are great, they let you put the weight where you want it (the compressor can sit at the bottom center of the robot, or be moved to either end to help balance) and you can add lightweight actuators wherever you want, without having to hassle with gearboxes and extra motors and speed controllers....and limit switches, encoders, PID loops, and all that fun stuff.

Our Lunacy robot moved balls in and out with motors and rollers, it worked very well. That year we got by with only one encoder and PID loop, the rest of the motors were just run when needed.

In the end, it doesn't really matter whether or not you use pneumatics, you can make a great robot with them or without. You'll learn different things, depending on what you use. It's all good.

RonnyV

14-04-2013, 13:27

We used them this year. Our rookie year, and I wished we would've used them more!

I really love pneumatics because of the speed/torque. And once it's airtight u don't have any problems at all.... like PWM cables coming lose during a game or something. Only down sides was your inches etc....

We as a Dutch team use different measurements etc.. gave us a set back from a round 1,5 week with stuff we needed to order.. but we got a great robot :D

And we're going to St. Louis and hopefully make it to our divisions eliminations!

Clem1640

14-04-2013, 13:44

There are a number of areas in which pneumatics out-perform motors (and, of course, visa-versa). Team 1640 usually uses pneumatic devices in our robots, but in two cases (2006 & 2012) we did not for weight-saving reasons.

Having the ability to utilize pneumatic actuators in our design process provides additional degrees of freedom to enable us to design the best robot that we can. More degrees of freedom increases design difficulty, but potentially (generally) improves the product performance. Having more degrees of freedom does not mean that you need to use them; this is part of the design decision tree which engineers need to make.

Vikingtech2054

14-04-2013, 15:30

We have used pneumatic every year you team has existed, i think if you know how to use them right and for the right applications they work well. There much fast than motor but there mainly limited to two positions. Heres a link (http://www.techvikes.com/previous-years/this-year) to our 2011 robot with a fully pneumatic arm and it was a very good robot. We won an event with it, one off-season event, two-time finalist (divisional Finalist) and semi-finalist at MSC.

CENTURION

14-04-2013, 16:05

Gregor

14-04-2013, 16:20

Very interesting design, but I can't see any air storage tanks in the photos, how many did you have, and where were they located?

I see 3 metal ones on this (https://3acfd444-a-630d28f7-s-sites.googlegroups.com/a/techvikes.com/tech-vikes-frc-2054/previous-years/this-year/IMG_1270.jpg?attachauth=ANoY7cq6uIPciJ71fHcqPrkObA 9EbXolnuuj5liaHePmFwGoyEHcogExVRfXZviBUYD2AdNovJxu kKcWQ4M5JT6LajJzYLBlKgsGJLQdodtV-cv0nLnoRgGb_5MhlWXYBzsc9iiV7sidKao1fczGHsKfVqac21q miUdIvYW_rWg_Ky14POX9djSfol_58RXy35wZZSPde_kcDZ6QY ayvlLDYaAfzH81vG0y4g7O4fMbgAN_WZ4jJJKeUG0wW1qLcEty zXGBdZtOB&attredirects=0) picture.

Tommy F.

14-04-2013, 16:25

1985 has never used pneumatics on a competition bot. I would suppose that our main reason for not using them is the weight; I think this year is the only year we've fielded a robot under 119lbs. The other factor has been the size required for the tanks and actuators and cylinders. We also like the added bonus of being able to skip the pneumatics portion of inspection. And since we have hardly used them at all, we find it easier to have a motor can complete a task rather than having air complete it, but that's just us. We've seen plenty of teams be very successful with pneumatics in their designs, so do whatever your team is good at.

Richard Wallace

14-04-2013, 16:37

... a lot of our leaks were coming from off-square cuts on the ends of tubes. This caused them, when plugged into a fitting, to not form a perfect seal. We solved that problem this year with a pneumatic tubing cutter (http://www.amazon.com/Compact-Cutter-Thermoplastic-Tubing-TC-01/dp/B007CJLG4Q/ref=sr_1_1?ie=UTF8&qid=1365823530&sr=8-1&keywords=pneumatic+tube+cutter) that makes it difficult to make a bad cut.These are an absolute necessity. Perfect cuts every time!
The tubing cutter linked above looks to be similar to McMaster-Carr pn/ 8288A51. Does anyone know from experience if one of these works better than the other?

CENTURION

14-04-2013, 17:31

I see 3 metal ones on this (https://3acfd444-a-630d28f7-s-sites.googlegroups.com/a/techvikes.com/tech-vikes-frc-2054/previous-years/this-year/IMG_1270.jpg?attachauth=ANoY7cq6uIPciJ71fHcqPrkObA 9EbXolnuuj5liaHePmFwGoyEHcogExVRfXZviBUYD2AdNovJxu kKcWQ4M5JT6LajJzYLBlKgsGJLQdodtV-cv0nLnoRgGb_5MhlWXYBzsc9iiV7sidKao1fczGHsKfVqac21q miUdIvYW_rWg_Ky14POX9djSfol_58RXy35wZZSPde_kcDZ6QY ayvlLDYaAfzH81vG0y4g7O4fMbgAN_WZ4jJJKeUG0wW1qLcEty zXGBdZtOB&attredirects=0) picture.

Right you are. With how often that arm would have been used in a match, would those three tanks really be enough to keep up with the air supply required?

The tubing cutter linked above looks to be similar to McMaster-Carr pn/ 8288A51. Does anyone know from experience if one of these works better than the other?

I haven't used that design specifically, I believe this (http://www.alliedelec.com/search/productdetail.aspx?sku=70070441) is the kind I have used. don't remember the brand, but it looks exactly like that one.

who716

14-04-2013, 22:24

I am a huge fan of pneumatics they provide a lot for a alittle. last year we had pneumatics adjusting our shooter, and we could not afford the weight to mount a compressor on board. this year we got the new compressor the light one and it is awesome.

Vikingtech2054

15-04-2013, 09:32

I see 3 metal ones on this (https://3acfd444-a-630d28f7-s-sites.googlegroups.com/a/techvikes.com/tech-vikes-frc-2054/previous-years/this-year/IMG_1270.jpg?attachauth=ANoY7cq6uIPciJ71fHcqPrkObA 9EbXolnuuj5liaHePmFwGoyEHcogExVRfXZviBUYD2AdNovJxu kKcWQ4M5JT6LajJzYLBlKgsGJLQdodtV-cv0nLnoRgGb_5MhlWXYBzsc9iiV7sidKao1fczGHsKfVqac21q miUdIvYW_rWg_Ky14POX9djSfol_58RXy35wZZSPde_kcDZ6QY ayvlLDYaAfzH81vG0y4g7O4fMbgAN_WZ4jJJKeUG0wW1qLcEty zXGBdZtOB&attredirects=0) picture.

We ended up actually buying 7 plastic air tanks that were about the same size as those ones and have used them for the last couple of years. I know it sounds like a lot but the robot was really simple compared to having a lot of motors. Mainly there was only four drive motors and 6 solenoids. Especially programming for teleop took like 20 mins which was very easy

theun4gven

15-04-2013, 10:45

I haven't used that design specifically, I believe this (http://www.alliedelec.com/search/productdetail.aspx?sku=70070441) is the kind I have used. don't remember the brand, but it looks exactly like that one.

This is the cutter we use. It's an SMC branded TK-3. From experience it is more reliable than the ones posted above and locks closed after use for safety. I have no problem keeping this thing in my pocket.

To touch on the OP: Our team uses pneumatics when they seem to be the best solution for the job. It turns out that we have ended up using them every year except 2009 (Lunacy). They work well for us this year due to a lot of binary movement designs (Shooter up/down, 10 point hang up/down, load disc, etc.) and justified the weight of the pneumatic system.

It is not out of the question to design a system without an onboard compressor. This can save quite a bit of weight and make a single actuator for one purpose worth it.

Basically, there are many correct solutions. Use what works best for you in the situation.

Something else I've noticed is that quite a few teams stack all of the required high pressure side parts (pressure switch, vent plug, etc) on a long chain of brass blocks. This is very heavy and many of these parts can be piggybacked on other required parts to save weight.

MichaelBick

15-04-2013, 11:59

This is the cutter we use. It's an SMC branded TK-3. From experience it is more reliable than the ones posted above and locks closed after use for safety. I have no problem keeping this thing in my pocket.

To touch on the OP: Our team uses pneumatics when they seem to be the best solution for the job. It turns out that we have ended up using them every year except 2009 (Lunacy). They work well for us this year due to a lot of binary movement designs (Shooter up/down, 10 point hang up/down, load disc, etc.) and justified the weight of the pneumatic system.

It is not out of the question to design a system without an onboard compressor. This can save quite a bit of weight and make a single actuator for one purpose worth it.

Basically, there are many correct solutions. Use what works best for you in the situation.

Something else I've noticed is that quite a few teams stack all of the required high pressure side parts (pressure switch, vent plug, etc) on a long chain of brass blocks. This is very heavy and many of these parts can be piggybacked on other required parts to save weight.

Plastic manifolds are another really nice way to reduce the weight of a pneumatics system