View Full Version : Pnumatic Rules Suggestions/Gripes
Rickertsen2
10-07-2004, 17:26
Over the summer i have been working for a pnumatics company. The other day i was thinking about FIRST and realized that the pnumatic systems involved in FIRST robots seemed almost silly and absurd after the things i have been working on. I laughed when i whough about the cobbled together mass of disposable cylinders and haphazardly strewn about valves by different manufacturers. I would like to hear what other peoepl think about lifting some of the pnumatic restricions. Below are some of the areas whre i have a problem and what I would do to change them if i were supreme dictator of the first world.
NEGATIVE PRESURE SYSTEM RESTRICTIONS:
Ok this is the big one. This is what really prompted my post. I have worked with vacuum handling systems for microchips, cardboard boxes and water bottles all the way up to full 80 gallon drums. I have been amazed at how useful and how versatile, effective and at the same time how simple such systems can be. I think that FIRST should allow Vacuum generators and suction cups.. This alone would open a whole new dimension to they way FIRST robots manipulate things... If there were two components that i could have added to the KOP, they would be a vacuum generator and a suction cup. Its unbeliavable how easy it is to pick up just about any object with these things.. Of course, Vacuum generators are somewhat of air hogs. We would either need a higher primary side pressure, larger accumulators or a beefier compressor. I havnt' done the math, but matches are rather short, and It seems to me that if we were given larger accumulators we would be okay. The past few years, FIRST has allowed us to use cups with integrated vacuum generators, so why not allow us to seperate them. If you can come up with any reason whatsoever why we should not be allowed to sue vacuum systems, I would love to hear it.
ACTUATOR RESTRICTIONS:
Why are we limited to what are more or less bottom of the line plain jane cylinders. There are many places whre a rodless cylinder, Pnumatic gripper, multipostion cylinder etc would be of great benefit. It seems to me that the reasons behind most of the actuator restrictions are safety related. Chioces do not have to be sacrificed to achieve this. If i were supreme dictator of the FIRST world, i would allow any actuator by any manufacturer so long as if fell within a certian maximum output force criterion.
VALVING RESTRICTIONS:
I think teams should be able to use whatever valves they want so long as things come to rest when the E-Stop button is pressed (IE: everything electrically actuated. No air piloted valves and air logic.) Actually on second though i think teams should be able to use all the air logic, porportional valves etc they desire. The following is a common practice in industry and someting that could apply to a first robot to allow some of the pnumatic restrictions to be safely lifted. We have a NO 3-way single solenoid valve controlled by a spike relay. Port one( input) is plumbed to the output of the primary regulator. Port 2 is connected to to all downstream components. Port 3 is vented. When the robot is disabled, so are spikes and thus our safety valve. No compents other than the compressor, primary regulator, and acumulators have any pressure. Everything else is vented Once the robot is activated, the valve shifts and everythign gets pressure.
I'm getting bored of writing now, and i havn't proofread any of this, so if it makes no sense o well.. I'm not sure how many peope hang out on these forums during the summer, but if there is anybody here, I think this would make for an interestin discussion and i am eager to hear other peope's opinions.
Billfred
10-07-2004, 18:26
I'm no pneumatics expert by any stretch, but I distinctly recall seeing a few Palmetto robots using suction to handle the 2X balls. 1398 (Keenan HS RoboRaiders) had the system going, but I don't remember how well it worked.
I do remember the Firebirds' setup quite well. I remember them building an air pump using a kit motor of some kind and using it for suction for their cup on top. They capped quite a few times, although I seem to recall the setup releasing the magic smoke once right at the end of a match.
Can anyone more familiar with either help jog my memory?
Joshua May
10-07-2004, 19:09
I'm no pneumatics expert by any stretch, but I distinctly recall seeing a few Palmetto robots using suction to handle the 2X balls. 1398 (Keenan HS RoboRaiders) had the system going, but I don't remember how well it worked.
I do remember the Firebirds' setup quite well. I remember them building an air pump using a kit motor of some kind and using it for suction for their cup on top. They capped quite a few times, although I seem to recall the setup releasing the magic smoke once right at the end of a match.
Can anyone more familiar with either help jog my memory?
I know that 69 had a suction device, although I have no idea how it worked.
Rickertsen2
10-07-2004, 20:00
The current pnumatics rules DO allow for vacuum systems which generate negative pressure by using a System in which suction is generated by pressurizing one port of a cylinder, and using the suction from the other. This Can be efficient in terms of air usage if done properly, but is VERY bulky compared to venturi pumps and can be a bit of a hassle.
The current pnumatics rules DO allow for vacuum systems which generate negative pressure by using a System in which suction is generated by pressurizing one port of a cylinder, and using the suction from the other. This Can be efficient in terms of air usage if done properly, but is VERY bulky compared to venturi pumps and can be a bit of a hassle.
I know this may sound like a stupid question but isn't a venturi pump the same way the automatic fertilizer mixers work.
Max Lobovsky
11-07-2004, 00:38
I'm not sure how an automatic fertilizer mixer works, but a venturi pump is pretty simple. In its most basic form, have a T-junction of pipes, blow air down the not-dead-end pipe of the T and you have negative pressure on the dead-end pipe.
Because of Bernoulli's principle (faster fluids have lower pressure than slower ones), The speed of the driving air cause's its pressure to drop into negative range. The T junction lets you access this negative pressure.
I'm not sure how an automatic fertilizer mixer works, but a venturi pump is pretty simple. In its most basic form, have a T-junction of pipes, blow air down the not-dead-end pipe of the T and you have negative pressure on the dead-end pipe.
Because of Bernoulli's principle (faster fluids have lower pressure than slower ones), The speed of the driving air cause's its pressure to drop into negative range. The T junction lets you access this negative pressure.
Demonstration of a Venturi pump (http://www.michaelv.org/ideas/labs/bazooka.php)
I'm not sure how an automatic fertilizer mixer works, but a venturi pump is pretty simple. In its most basic form, have a T-junction of pipes, blow air down the not-dead-end pipe of the T and you have negative pressure on the dead-end pipe.
Yeah thats the whole concept. The negative pressure is used to suck up the fertilizer. I can't believe no one has used one. They hook up onto the hose. Only reason why I asked is because my uncle told me that the mixer uses a venturi straw. Why can't someone build a venturi pump. It really doesn't seem that hard.
Rickertsen2
11-07-2004, 14:35
Yeah thats the whole concept. The negative pressure is used to suck up the fertilizer. I can't believe no one has used one. They hook up onto the hose. Only reason why I asked is because my uncle told me that the mixer uses a venturi straw. Why can't someone build a venturi pump. It really doesn't seem that hard.
To build a Venturi Pump would be reinventing the wheel. They are readily available off the shelf. Building a venturi pump the quality of those commercially available would be very difficult. It has taken years of developement to get to the level of design tweaking they are at. most use several stages and valves which open and close to adjust to varrying vacuum conditions (IE: they put the stages in parallel when high flow low vacuum conditions are encountered, and in series when high vacuum is needed). I really can't figure out why FIRST doesn't want us to use these. They present no safety hazard, and could be of great benefit.
If you went to the pneumatics meeting at Atlanta we talked about some of these things. There is a company, can't think of, someone jog my memory that was looking into donating venturi style vaccum generators that weighed less than a 1/4 pounds, barely used any air, and had tremendous suction. If someone else knows the companies name and the device name clue everyone in. But this would solve everyones suction needs.
Another thought is raising the restrictions on the number of accumalators. This would give some more room to store air. But you got to be careful so that you aren't jeopardizing the pressure of the system.
About valve I see that it would be nice to have more options but still keep the creativity in it. You can still do a lot with what they have this year. And general restriction were fairly loose.
And for different kinds of actuators. They are honestly working to get you the best and most useful actuators. They added the rotary actuator and the actuator with magnectic reed switches(common in industry) this year and look for more ways to get us the equipment we want and need. I'm sure if you wrote out the actuators you thought would be the most beneficial, and cost efficient as a donation, and got the list to the guy who gave the presentation at the pneumatics workshop (name escapes me, look it up under the FIRST convention) he would be willing to talk, take input, and see what he could do about getting FIRST the best possible kit.
Andy Brockway
12-07-2004, 09:50
VALVING RESTRICTIONS:.........
The following is a common practice in industry and someting that could apply to a first robot to allow some of the pnumatic restrictions to be safely lifted. We have a NO 3-way single solenoid valve controlled by a spike relay. Port one( input) is plumbed to the output of the primary regulator. Port 2 is connected to to all downstream components. Port 3 is vented. When the robot is disabled, so are spikes and thus our safety valve. No compents other than the compressor, primary regulator, and acumulators have any pressure. Everything else is vented Once the robot is activated, the valve shifts and everythign gets pressure.
The example you cited is important for safety in industry, a critical need to dump all energy sources. While this is a common practice in industry it may not directly apply to FIRST. Many teams, including ours, use the air pressure in the disabled mode to position a part of the robot at the beginning or end of the match. This years example is all the hangers that withdrew their feet when the match ended.
Pat Roche
12-07-2004, 18:07
I have so many comments and ideas on this topic I dont even know where to start.
I have been doing research and such in pnuematics pretty actively for the past year or so. I have generated suction systems, recycle systems, multi-positioning systems and many more.
I could be wrong but I don't recall the use of venturi pumps being illegal this past season. In fact I think that may have been what team 69 used. I know for the offseason competitions we have been developing a suction system for manipulating 2x balls. To do this we have integrated I have integrated a venturi pump into the system and it works beautifully. To stop the flow of air through the pump all you have to do is place a solonoid on each side of the pump, that way you can turn your airflow off and still hold onto whatever object you are grappled onto(at least thats the way we have to do it with the pump we have).
As far as valve restrictions I tend to disagree with rickertsen's 3 way valve. This problem with it is that in a machine that uses lots of pnuematics(ie. 134 bot this past season which ran only two motors) it takes time and power to charge this system. Having a 3 way on a machine like that counters some of your previous arguements. (i could have misinterpretted you however)
Otherthings id like to see changed is that i think you should be able to make your own custom air containers. Using Copper piping to create an accumulater might be lighter than current accumulators and would be cheaper. To test for leaks in my current job (running pipe with plumbers) we pressure the system well over 100lbs of pressure and the pipes hold with solder. Its and economical solution that is cheap and allows for custimization of a system.
Ill prolly come up with some more stuff...
So please ponder some on these thoughts
-Pat
I have so many comments and ideas on this topic I dont even know where to start.
I...
Otherthings id like to see changed is that i think you should be able to make your own custom air containers. Using Copper piping to create an accumulater might be lighter than current accumulators and would be cheaper. To test for leaks in my current job (running pipe with plumbers) we pressure the system well over 100lbs of pressure and the pipes hold with solder. Its and economical solution that is cheap and allows for custimization of a system.
Ill prolly come up with some more stuff...
So please ponder some on these thoughts
-Pat
I assume that the pipes you refer to are water pipes. There is a world of difference in the failure of a hydraulic system, such as a water pipe filled with water, and that of a pnuematic system. Pnuematic sytems are considered "pressure vessels".
A pressure vessel refers to any container that encloses material that tends to continue expanding when pressure is released. Pressurized air and steam are common examples.
Let's look at a vessel like an one of our accumulation tanks. Let's say you were to fill it with water, pressurize it and then seal it. If the accumulator should start to fail, then as soon as any water leaked out, the pressure will be relieved and the failure would stop. This happens nearly instantaneously.
Now let's try it again with air. Here when the leak starts, the pressure remains nearly the same as what it was before. The failed part continues to fail because it remains under load. There is a good chance that eventually something is going flying in a random direction in this scenario.
The design of pressure vessels is strictly regulated and can only be legally performed by people who are qualified by the State to do so. Those people are Licensed or Registered Mechanical Engineers (the exact term varies by state). There are a few of them running around here on CD, I am one of them, Dr Joe is another. I don't think either of us is familiar enough with the ASME boiler code, which regulates the design of pressure vessels, to be able to design our own and be sure of meeting all of the requirements. The companies that make pnuematic hardware are knowledgable about the code and follow it pretty strictly. It is the "standard of practice" in this area and not following it leaves you pretty wide open for liability suits should anything go wrong. Not to mention the fact that people might get hurt.
It is interesting to note that the ASME Boiler Code came about because somebody noticed around the turn of the century that boiler explosions were one of the top ten leading causes of death. The ASME decided that they should codify the best design practices and eliminate this entirely preventable calamity. This approach has been extremely successful. The last time I even heard about somebody even being injured in a boiler accident was ten years ago and it involved an antique steam locomotive that may have been built before the Code was created.
So there are darn good engineering reasons NOT to have you guys building your own custom tanks etc. In my opinion, it is the pnuematics, not the electronics, that have the highest potential for injury on a FIRST robot. So treat them with the respect they deserve and don't "meddle in the affairs of wizards".
Elgin Clock
12-07-2004, 22:39
Ugghh... Pneumatics.. My second least favorite system on the robot next to Electronics.
Anyways, personal opinions aside, let's look at this from another standpoint.
If you were designing a game for HS kids to play/compete in, and you also got to choose the parts they use... then.. would you:
A) Let them (the HS kids) have free range and give them anything they wanted to use which would defeat the purpose of learning how things work and teach them only how to assemble parts together to work.
or
B) Would you restrict the supplies to the most basic of fields, (Pneumatic -tanks, regulators, hoses, compressors, etc...) (Electrical - chips, wires, switches, etc..) (Mechanical - Metals, Plastics, Woods:rolleyes: , etc...) Then the HS kids would have to make their own system (ie: robot) to whatever possible combinatoin of the basic parts they have available.
I personally would choose B. It's not what you can do sometimes, it's how you can accomplish it that seperates the thinkers from the assemblers.
Granted, I would love to use a ready built component rather than make one myself, but in a competition based on learning and inspiration.. Isn't that defeating the point??
I think elgin and chrish hit a lot of good points.
FIRST is working to give us the safest and most effective parts they can give us. At the pneumatics meeting we talked about a compressor that weighed 1/3 the weight but wasn't as fast at recycling. We talked about lighter accumulators more like a PVC type. We talked about more accumulators. These things are all taken into consideration. Most of all FIRST wants us to be safe and follow good design practices.
And this is about design. I always love to see what new things teams come up with. I've been proud to have suction (non-pneumatic) this last year, and multi-position actuators the previous. It took some thought but worked out great in both cases. Elgin really gets to this one. Do you want it to be the best robot or the best engineered. Like Dave said at Atlanta. We are going to have a certain amount of parts we can use on Mars and we've got to make them work. We can't go to the hardware store and buy it completely finished and ship to Mars. Same here. I like some freedom. But the constraints make the game interesting. IMHO.
Pat Roche
13-07-2004, 14:59
At the time of my post I wasnt aware of such ASME codes. I didnt mean to question the itegrity of such codes. I was just suggesting a possible alternative(even though its not quite researched).
BTW we pressurize our water systems with air to check for leaks before we allow water to move through them. We pressurize them at around 130psi
Sorry for the confusion
-Pat
At the time of my post I wasnt aware of such ASME codes. I didnt mean to question the itegrity of such codes. I was just suggesting a possible alternative(even though its not quite researched).
BTW we pressurize our water systems with air to check for leaks before we allow water to move through them. We pressurize them at around 130psi
Sorry for the confusion
-Pat
Pat,
I didn't think you were questioning their integrity, I just figured you were ignorant. Most people are about such things. Heck, I went to engineering school and they didn't talk about the Boiler Code much there either. I didn't learn much about it until I started studying for the License Exam.
BTW being ignorant about obscure technical subjects is not a reflection of your general mental abilities. It just means you haven't been exposed to that area of knowledge.
Of course if you are exposed and refuse to take into account what has been learned, then you move from Ignorance to Foolishness. The book of Proverbs in the Bible has a lot to say about fools, none of it good.
Depending on the application, testing piping with air may or may not be a good idea. In this case the pressure is reasonable and it is not for an extended period. Using an ultrasonic leak detector could also help find problems like small leaks before you make a big mess. The air is much more likely to leak through small holes than water and is much easier to clean up than water. But if a fitting was very poorly soldered, then it might also become a projectile.
It all depends on your prefered risk. In new construction for a house it might not be a great idea. But if you're retrofitting a building with lots of wiring and expensive electronics, like a recording studio or radar station then the risk might be worth it.
Rickertsen2
13-07-2004, 20:56
As far as valve restrictions I tend to disagree with rickertsen's 3 way valve. This problem with it is that in a machine that uses lots of pnuematics(ie. 134 bot this past season which ran only two motors) it takes time and power to charge this system. Having a 3 way on a machine like that counters some of your previous arguements. (i could have misinterpretted you however)
The valve WOULD NOT dump the accumulators, only depressurize downstream components. it does however create the below issue.The example you cited is important for safety in industry, a critical need to dump all energy sources. While this is a common practice in industry it may not directly apply to FIRST. Many teams, including ours, use the air pressure in the disabled mode to position a part of the robot at the beginning or end of the match. This years example is all the hangers that withdrew their feet when the match ended.
This is one thing i overlooked, but that could be prevented by using a 3 position double spring return valve with a blocked neutral state. Of couse judging by the dissaray of valves that have come in the kits the last few years, I think FIRST already has a hard enough time getting valves donated without going into anything fancy. But then agian the whole point of my crusade is to allow us to use one of those if we should so desire. I saw some weird combinations of valves to achieve multipostitioning etc that could have been achieved with a single part if we were not soo restricted.
If you went to the pneumatics meeting at Atlanta we talked about some of these things. There is a company, can't think of, someone jog my memory that was looking into donating venturi style vaccum generators that weighed less than a 1/4 pounds, barely used any air, and had tremendous suction. If someone else knows the companies name and the device name clue everyone in. But this would solve everyones suction needs...
The company was probably PIAB, whom my company is a distributor for and whose products i work with on a regular basis. These are exactly what i am referring to. In fact i can say that you are probably referring to either an Mini Chip M(xx)LP pump or a P3010 series pump. The Mini Chip M(xx)LP pumps weigh only a 16th of a pound and is 16.5mm high, 61mm long, and 30mm wide. I havn't weighed a P3010 pump (which is a little more efficient and has an integrated filter, but a stack of 2 would probably be needed in a robot that relied heavily on vacuum). The Mini Chip M(xx)LP pumps can generate a vacuum of up to 24.1-inHg with various max flow rates and air consumptions depending on what you fill the "xx" in with, from a 55psi supply. The P3010 pump can generate a vacuum of up to 27.0-inHg from a 45psi supply and has a max flow rate of 2.97scfm while consuming 1.00scfm of compressed air.
As an addendum to my previous comments, about allowing a greater selection of actuators, i was really referring to two things.
1.) I do not think we should be given a list that says "you can use these sylinders and no others", rather i think we should be given guidelines similar to the allowable parts flowchart. An example of the absurdity of the current regulations was the issue where peope were pressing out the clevis pin to get their cylinders to mount how they wnated them to. This could ahve bene avoided entirely if FIRST had just let us buy the proper cylinders in the first place. Bimba offers their classic line of cylinders with about a dozen different mounting options. Someone find me a reason why we shouldn't be able to use a cylinder that bolts down instead of using brackets, or why we shouldn't be able to use one with a hole instead of a clevis pin? There us a reason why the Bimba Classic line catalog takes up 152 pages.(The classic line is the series of cylinders provided in the FIRST kit.)
2.) I am happy about rotary actuators being allowed this past season, and i saw some creative uses for them. There is one other actuator i think should be allowed, that is the rodless cylinder. For those of you who have never seen a rodless cylinder, Here is a link to a pic of one as an example. http://www.oylair.com/graphics/bimba_ultran_rodless_cylinder.jpg
I'm not saying that these things need to be incuded in the kit, only that they should be ALLOWED.
O one last thing. limiting selection ENCOURAGES BAD DESIGN PRACTICES. It teaches kids to use the wrong parts for the wrong purpose. The proper design practice is to use the right part for the job. I think that by allowing the proper parts, we would be raising the bar of FIRST stardards not lowering it. Robots would get more complex, not more like a lego set. We have only 6 weeks to build a robot. If we wasted less of that time on menial tasks such as hacking togther assemblies to use a standard cylinder as a rodless sylinder and focused more of our energies on important tasks, we could do alot more.
Amen, James. If this goes through, no more miles of tubing to increase our air capacity for us!
But this means no more late nights spend checking every inch of tubing for leeks, just you and me, all alone in the dark technology room.
-Chris
Andy Brockway
14-07-2004, 08:06
O one last thing. limiting selection ENCOURAGES BAD DESIGN PRACTICES. It teaches kids to use the wrong parts for the wrong purpose. The proper design practice is to use the right part for the job.
This is not really encouraging bad design practices. In many companies there is a restriction on increasing the spare parts inventory. The solution to this is to see what is available in the parts crib, our real life 'kit'. While this does not always produce the 'best' design, it does provide a workable design without increasing the overhead in the plant. If I really do need something new, I can.
Of course the distributors and all my suppliers think I need the latest and greatest and don't worry they stock it for me. Unfortunately at 1 AM when the machine is down, their stock room is not open immediately.
I must admit that the 'kit' at the plant is a whole lot bigger and does gives me more choices. :D
Mike Martus
14-07-2004, 08:21
If you are working for a pneumatics company this would be a great opportunity to talk to them about FIRST and possibly being a supplier.
One of the restrictions (a very good one) of FIRST is to make sure materials and parts of all robot building is accessable to all teams (not including custom design and fabrication of some raw materials). The parts we have in the kit and parts allowed from a list are based upon safety as wells as availability. In some cases parts are donated and often purchased for the kit or from a specific list from a specific supplier (sort of payback for their donation).
Keep talking about improvements to the kit and make sure you pass on all suggestions to FIRST - they listen to teams and experts on teams. Most of the recent changes are a result of suggestions like found here in this thread.
Rickertsen2
14-07-2004, 12:18
Does anybody know who at FIRST i might try and talk to about this and how i can reach them?
Does anybody know who at FIRST i might try and talk to about this and how i can reach them?
I'd try this guy:
Fred Hord of Hydraulic & Pneumatic Engineering Company, Inc. in Deerfield Beach, Florida.
I can't say yet how to contact him but I'll look some more. Couldn'tfind it. Ask FIRST. If that fails look to the people who organized the convention. Only names I can think of are Tonya Scott and Erin Rapacki.
He was the main speaker in the pneumatics workshop and helps organize the pneumatics part of the kit.
Pat Roche
14-07-2004, 15:45
The valve WOULD NOT dump the accumulators, only depressurize downstream components. it does however create the below issue.
That is a problem when you have a 2"x24" piston and a 2"x12" piston on your machine. It takes our system a quarter of the match to charge fully(thank goodness we only need it once or twice a match). That is also the reason we have developed the recycle circuit.
What Im wondering is if there is a solonoid valve that can be used for a multiposition pnuematic system(IE:one valve instead of two or more). I ask this because using two solonoids is really draining on a new or small teams resourses and it would simplify my pnuematic boards quite a bit :rolleyes:
-Pat
Pat Roche
20-07-2004, 21:27
Another thing that I have been pondering about is the use of different kinds of pistons...This year the rotary device was added. There are many different pistons out there and many would be useful...an example would be a double ended piston (lets see if i can do art....)(sorry for the lack of terminology)
---||||||-------- <---one direction
-------|||||||--- <---the other direction
For pistons like these i see enormous value and an almost endless design advantage. It would simplify many of our current pneumatic systems and open a world of new ideas/options teams have.
-just some thoughts to ponder upon
-Pat
Squirrelrock
07-12-2004, 14:19
I'm no pneumatics expert by any stretch, but I distinctly recall seeing a few Palmetto robots using suction to handle the 2X balls. 1398 (Keenan HS RoboRaiders) had the system going, but I don't remember how well it worked.
I do remember the Firebirds' setup quite well. I remember them building an air pump using a kit motor of some kind and using it for suction for their cup on top. They capped quite a few times, although I seem to recall the setup releasing the magic smoke once right at the end of a match.
Can anyone more familiar with either help jog my memory?
I was at VCU, and we (617) were the only team to use suction that I remember. We had a dustbuster mouth (right where the motor-fan part is), but we replaced the original motor with a legal one (fisher price, i think) and sealed a pie pan onto the mouth. The ball could be lifted, but if the robot moved, the ball would fall off.
There is an on line video for pneumatics found at:
http://www.usfirst.org/robotics/2003/online.htm
Also this link to suppliers for 2004 has a Pneumatics questions and problems number.
http://www2.usfirst.org/2004comp/2004_FRC_Kit_of_Parts_Supplier_Contacts.pdf
I actually call the number last year as I was new to pneumatics and I was suppose to show the students how to do it. The people were really helpful. hope that this helps some people out.
Chris Fultz
08-12-2004, 22:41
Amen, James. If this goes through, no more miles of tubing to increase our air capacity for us!
-Chris
This is against the rules. Read 5.2.1 for the specific statement, and then also refer to the Q & A on-line sessions from 2004. The specific question was asked about using pneumatic tubing as a reservior - answer = NO.
Jeffrafa
09-12-2004, 04:07
I actually thought the pneumatics rules were quite open and not really very restricted, as some of you seem to think. Given last year was my rookie year, but my dad has also sold pneumatics for 20 years, so i do have some previous experience and exposure to them.
The restrictions that they do have only make sense - you halfta have standards set for things like compressors and accumulators or there's no way that it could even be a remotely fair playing field. I can sympathize with needing more or larger air storage, but this should still be something that is standardized, either with having an additional clippard tank or two larger tanks - not by just allowing people to pressurize whatever they can get ahold of.
As far as actuators are concerned, Section 5.2.9 <R54> states "There is no limit to the number of solenoid valves, air cylinders, and connecting fittings you may use on your robot. They must, however, be “off the shelf” pneumatic devices rated by their manufacturers for pressure of at least 125psi."
That rule states there is no limit to the number of pneumatic devices, so long as they are commercially avalible and rated for at least 125psi. This would include rodless cylinders, rotary actuators, pneumatic grippers, multiposition cylinders, and countless solenoid valves, for these are all avalible from any number of different manufacturers. I don't see how that seems restricted.
FIRST dosen't half to supply everything that you can use in the kit, and we shouldn't expect them to - although they do give you plenty to work with. Pneumatic actuators are an example, they give you some to work with, but that dosen't mean you are limited to what they give you.
Our team had a number of complexities in our pneumatic system last year. We didn't have any specialty actuators, but we did run both 30 and 60 psi in order to save air where we didn't need high force. We even had two cylinders which we could switch between the two pressures by using a solenoid valve backwards and plugging the exhaust ports, this would let us raise our hook while saving our air for when we needed it to actually hang. We had 2, three position solenoid valves and we also had an air filter hooked up just after our compressor to help eliminate some of the moisture we were getting built up in the air system, certianly not something FIRST robots usually, or mabye even have ever had - but it is standard in industry application.
Anyways, thats just a few of my thoughts
Feel free to comment back or correct me if i may have misspoke,
Jeff
Andy Brockway
09-12-2004, 08:15
As far as actuators are concerned, Section 5.2.9 <R54> states "There is no limit to the number of solenoid valves, air cylinders, and connecting fittings you may use on your robot. They must, however, be “off the shelf” pneumatic devices rated by their manufacturers for pressure of at least 125psi."
That rule states there is no limit to the number of pneumatic devices, so long as they are commercially avalible and rated for at least 125psi. This would include rodless cylinders, rotary actuators, pneumatic grippers, multiposition cylinders, and countless solenoid valves, for these are all avalible from any number of different manufacturers. I don't see how that seems restricted.
This is mostly correct. <R54> also limits where you can get the solenoid valves and air cylinders thus eliminating the majority of actuators on the market. The Flowchart is very strict, the answer is NO for just about any pneumatic device. Unfortunately the air filter you used was also not allowed as it is not a connector or an approved device. It is a great idea and something that is installed on all equipment in my plant.
Pneumatics, and electrical, have been the most tightly controlled areas of the robot. The reason is safety. Many teams have members with experience in these areas. But think of the rookie team consisting of one science teacher and students who never worked with air before. The rules are their roadmap to prevent accidents.
There is no limit to the number of solenoid valves, air cylinders, and connecting fittings you may
use on your robot. They must, however, be “off the shelf” pneumatic devices rated by their
manufacturers for pressure of at least 125psi. Besides the “free” pneumatic components listed on
the Pneumatic Components Order form, you may use additional air cylinders or rotary actuators,
however, they must be identical to those listed on the Pneumatic Components Order form, and
obtained from a Bimba or Parker Hannifan distributor.
This was from the rules of 2004. The only exception that I know of was that Canadian teams had SMC cylinders donated and they were allowed. Last year they were very strict on all pneumatics. There were some different rule interpretations but most issues followed the rules to a T.
Billfred
09-12-2004, 09:40
This is mostly correct. <R54> also limits where you can get the solenoid valves and air cylinders thus eliminating the majority of actuators on the market. The Flowchart is very strict, the answer is NO for just about any pneumatic device. Unfortunately the air filter you used was also not allowed as it is not a connector or an approved device. It is a great idea and something that is installed on all equipment in my plant.
Pneumatics, and electrical, have been the most tightly controlled areas of the robot. The reason is safety. Many teams have members with experience in these areas. But think of the rookie team consisting of one science teacher and students who never worked with air before. The rules are their roadmap to prevent accidents.
A-men. Last year, 1293 fell on the wrong side of that rule with our actuator (I think that's the technical term--we dealt with it for about five days before shipping, when a million things are on our minds) for our 2X ball gripper. We came up with a simple solution that made the inspectors happy--we disconnected the air lines and turned it into a darn expensive structural member.
Moral of the story? Read the manual--all of it!
Jeffrafa
09-12-2004, 13:54
Unfortunately the air filter you used was also not allowed as it is not a connector or an approved device. It is a great idea and something that is installed on all equipment in my plant.
Just a response to our air filter - the judges did discuss it at both regionals that we competed in and decided it was fine, although they did let us know if there was question from other teams then they may half to make us remove it.
Just because volunteers OK at one regional does not make something legal. There have been many times that things are missed or overlooked but then noticed at another event. A rule is a rule. Sometimes we don't even realize there is a problem. Our team used a wrong Victor once and it wasn't caught until the second regional. It was missed by both us and a set of inspectors. Once pointed out we corrected the problem. Last year I saw teams with bad or wrong wiring and pneumatics that passed at one regional and they were upset that they had to redo at the 2nd regional. As inspectors we have a lot of robots to see in a short time and a lot to cover. We will occasional miss some items.
Just the fact that you were told that you would have to replace it if questioned says to me that the inspectors knew that there was a problem but didn't want to deal with it.
roboguy #1
14-01-2005, 23:58
If you look at the stock compressor they give you, you will happen to notice that it has a suction/vacum port and a pressure port as the pump I belive is dyaphram or piston it creates a pressure side and a vaccum side hook what ever to the vaccum side and amazing you got urself vaccum power and without adding stuff tada. look at it all pressure pumps can create at least some vaccum i mean how can it suck it into the pump chamber without vaccum u tell me
roboguy #1
16-01-2005, 00:14
I dont know how to delete posts or w/e so im sorry there isnt a suction port but im sure u could remove the air filter and test what it can do so i looked at teh pump and changexd my mind ps. tell me how to maniplulate posts.
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