Pnumatic Rules Suggestions/Gripes

[Rickertsen2]

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]

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]

Originally Posted by Billfred

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]

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.

[Adam Y.]

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]

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.

[jgannon]

Originally Posted by maxlobovsky

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

[Adam Y.]

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]

Originally Posted by Adam Y.

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.

[ngreen]

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.

[Rickertsen2]

Originally Posted by T134guy

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.

Originally Posted by Andy Brockway

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.

Originally Posted by ngreen

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...s_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.

[Squirrelrock]

Originally Posted by Billfred

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.

[Steve W]

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/200...r_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.

[Andy Brockway]

Originally Posted by Rickertsen2

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]

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