Dissadvantages of Suction?
 

This year my team is experimenting with a suction system for our robot. We're using venturi's and a suction cup to pick up the tubes. In our testing, it works great, and the seal is strong. But we have to keep the compressor going the entire time to keep up with the loss in air pressure, and we're afraid that our battery will die quickly. We are getting 3 new batteries this year, and we have several batteries from past years (although most of those are going bad). Our main concern is that we won't be able to charge our batteries quick enough between elimination matches (if we get into the elimination matches).

Can everyone voice their thoughts?

I like the idea of suction. It's simple to build, and inexpensive (we already have the parts). But many of my team are worried about the battery

Re: Dissadvantages of Suction?
 

You make a valid point and I have seen problems before us in 2005 we used venturi and barely got through a round on one battery. So my recommendation is go to eSTOP Robotics LLC website. They are underwritten by a first team outside of Philly they sell a device called the Custom Control Interface. Using this and some simple codeing your driver or operator could turn the pump on and off as they see fit. So when you are running around not holding a tube you could turn the compressor off. This might save enough power. Just a thought

I would speak to the eSTOP people first ofcourse. I believe they use this exact function on their own robot so they would be able to tell you in more detail.

Re: Dissadvantages of Suction?
 

Weight is one thing (compressor, air tanks) unless you already have a pneumatic system in play. Another is reliability, will it always grab the tube. Strength, if you get pushed is the seal going to break. Maintenance, leaks air hose coming undone.

Everything has its advantages and disadvantages so in the end its your call.

Re: Dissadvantages of Suction?
 

Also, remember that this year, there are no limits on pneumatic accumulators. Having a large reservoir of air available to you, and a fully loaded system at the start of a match, can cut down on the required compressor run time.

Re: Dissadvantages of Suction?
 

That was our main concern when reviewing suction. Personally, I doubted that it would work. But the tubes stuck really well (we had one person hold it up with a venturi while other people acted like robots and tried to knock it down) and it sealed perfectly as long as we had a high enough PSI

Re: Dissadvantages of Suction?
 

Thanks, I'll look into it

Re: Dissadvantages of Suction?
 

For what it's worth, we looked at suction pretty hard in 2007, and ended up abandoning the idea. We could never get a system together that could reliably pick up the tubes without requiring extreme precision, and the battery requirements for it are pretty intense. We've steered away from suction ever since.

Re: Dissadvantages of Suction?
 

my team tryed out a suction system where we used a shop vac and a mask used in cpr. the suction held when we shook the tubes back and forth but only would drop when we turned off the power. one of the proubles we had was going in with a suction method you had to grab the opposite end of the tube.

Re: Dissadvantages of Suction?
 

The disadvantage of Venturi Driven suction is that it requires a Pneumatic System to function which means you're adding a minimum of an extra 10lbs or so if you have the compressor on board and a reasonable amount of air tanks.

There are other options available to create a reliable vacuum driven mechanism, perhaps the most common is to take a commercially available vacuum impeller and retrofit one of the KOP motors to it. The motor only has to run while you need the vacuum, which should draw less power over the course of a match than a compressor. This method has been used by teams in the past to hold Soccer Balls, Track balls, and Tubes so it's proven as long as you can get your implementation right.

One of the downfalls of suction is that the surface of the object has to be relatively uniform which makes positioning key. You may or may not be better off pursuing another option.

Re: Dissadvantages of Suction?
 

We have considered that idea. What would you suggest we try? I know a lot of teams have used shop vacs in the past

Re: Dissadvantages of Suction?
 

To be completely honest, I don't really know. Most of the systems I've seen have used a shop-vac or other heavy duty vacuum.

Re: Dissadvantages of Suction?
 

Buy a shop vac from Home Depot and take it apart and you should be good. I don't have a specific model, but I heard that the model 228 used basically came ready for an FP motor retrofit out of the box.

That said, I would make sure you put a lot of thought into your cup design to make sure you're getting the best possible hold on the tube.

Re: Dissadvantages of Suction?
 

last year we just ordered the impeller from the manufactures replacement parts website.

Re: Dissadvantages of Suction?
 

Ryan:

We used a vacuum system last year by making our own impeller. We took apart an 18volt hand-held vacuum and re-engineered their impeller for our purposes. It was created in our 3D printer at school. It worked great. I have enclosed a few picts of the system. If you can use the CAD files, I would be happy to pass them along.

Re: Dissadvantages of Suction?
 

It should be noted that there will be significant differences between an impeller based system and a venturi based system as described here. You may not be able to get the same strong hold with an impeller based system.

Re: Dissadvantages of Suction?
 

We also used a vacuum system last year, but all we did was rip the impeller out of a shop vac and hook it up to a geared up cim. It worked pretty well, but we gained a reputation for our incredibly loud robot. You would also need a way to turn off suction. Last year, we used our kicker to get it off of the tubes, but I don't think using a kicker will be as good of an idea this year XD

Re: Dissadvantages of Suction?
 

Greetings from eStop Robotics!!!

Thanks to Liam for suggesting our Custom Controls Interface (CCI)!

Last year, a team we sponsor, Royal Assault Team 357, was able to use the impeller and tubing from a vacuum cleaner for a suction device. They were able to control it using custom controls.

This year we've introduced a new product, the CCI, for just this purpose. It is a simple, effective way to add custom controls to your robot.

The CCI has 12 digital inputs and 4 analog inputs. No special SW or drivers to install. It works with your Driver Station PC out of the box. Your cRio programming is also no different than using a joystick, the same functions are used for the CCI as a regular joystick.

The CCI can be used to wire up switches for your controls. Using the CCI and a switch, you could turn on or off your suction device when you want to during a match.

http://www.estoprobotics.com/estore/...d&productId=33

Good Luck to all the teams!!!

Re: Dissadvantages of Suction?
 

Our team tried to use a vacuum suction system last year for ball acquisition. Let's just say it didn't go well. First of all, it can be very heavy and space consuming, since the vacuum can weigh a ton, depending on what parts you use. Second, it is very unreliable, either not having enough power to pick up a ball, or having too much power and not letting go. I suggest using either something with pneumatics or surgical tubing/spring type system. good luck!

Re: Dissadvantages of Suction?
 

If you use a venturi type system, you could mount a high-sensitivity limit switch next to the end effector that only allows air through the venturi vacuum generator when the end effector was in contact with a tube. This, combined with many and/or large air tanks, could help conserve battery power.

Re: Dissadvantages of Suction?
 

team 1086 used a venturi system in 2007 with a decent amount of success. suction can really do a good job or holding on to the tubes once you find the right suction cup. the main drawbacks we experienced were a slower pick up and release time (suction takes a second to kick in a release) and the big one is battery consumption. even with 4 clippards on our bot we had to constantly run our compressor, leaving use with a nearly dead bot at the end of the match. it could make things hard when it comes down to deploying a minibot when you can hardly move. and like you said this may force you to borrow some batteries during elims.

Re: Dissadvantages of Suction?
 

What suction cup did your team use? We used an Anver VC25 http://www.anver.com/document/vacuum...s-vc253545.htm
We bought a suction cup to test and our initial results were not too stellar, although this was with only students testing (no mentor oversight). We connected a suction cup to the end of a pneumatic cylinder and pulled the piston, creating decent suction on a flat surface, but poor suction on the tube. (Originally, the design called for a second cylinder,pulling the piston of the first, but we were not able to complete it with the materials we had.)
We were not dead set on a suction cup; it was one of two possible attachments to our arm, the other being a simple tong mechanism. But I would like to see if the idea can be scrapped in any kind of way.

Re: Dissadvantages of Suction?
 

we used a vacuum last year, and it was a real battery killer, not to mention that it barely made it through the regional before wearing out.

Re: Dissadvantages of Suction?
 

suction just sucks, unless i'm cleaning up a mess i just stay away from it.

only tried it once
http://www.youtube.com/watch?v=sxDGLgaA3QY

Re: Dissadvantages of Suction?
 

We prototyped it this year, holds the tube well except for a side to side motion. Lots of air...

Re: Dissadvantages of Suction?
 

not always although i don't think this is the year for it we used 2 fp on our 2008 bot it was awesome

http://www.youtube.com/watch?v=QeQSGmFnKAE

also we used a 2 stage impeller which gives a higher delta-p