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Suction cups used to hold position at the end of the game, powered through a single 2" bored pnuematic cylinder, can withstand forces above 500 lbs. Good luck trying to move us 
Discussion
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26-02-2003 23:51
UlTiMaTeP
Our first ideas were to use out riggers and have 4 suction cups about that size or a little bit bigger, but after some testing we found out you could put 130 lb of suction cups if you wanted and they would do absolutely nothing. When you have a bot that weighs 130 pounds crash into you at 12 FPS your bot is gonna move thats a given, no matter how many suction cups you have.
27-02-2003 00:02
sevisehda
Suction cups are kinda sketchy in my view. First they are only meant to resist force trying to pull them away from a surface. Second they work best on smooth surfaces. They don't resist nearly the same amount of force laterally. The amount of grip there gonna provide on a gouged surface is nothing compared to a good high COF >2 material.
Saying that 130lbs at 10+ ft per second is alot of bot for anything to stop. Just think of all those walls people have dented with a rampaging bot. At this point I'd put my money on a bot that has an inclined surface such as 229 and swampthing.
Watch this vid to see what I mean about the incline of 229.
http://www.clarkson.edu/~usfirst/our...d/WingTest.avi
27-02-2003 00:14
Gope|
Originally posted by sevisehda Suction cups are kinda sketchy in my view. First they are only meant to resist force trying to pull them away from a surface. Second they work best on smooth surfaces. They don't resist nearly the same amount of force laterally. The amount of grip there gonna provide on a gouged surface is nothing compared to a good high COF >2 material. |
27-02-2003 00:33
SlamminSammy|
Originally posted by sevisehda Suction cups are kinda sketchy in my view. First they are only meant to resist force trying to pull them away from a surface. Second they work best on smooth surfaces. They don't resist nearly the same amount of force laterally. |
I personally thought my system was ingenious, but my team wouldn't even try it--possibly because it's never been tried before. I think this bumper system would make suction cups an invaluable resource.
Is this just my superiority complex speaking or was I on to something? (It's ok to be brutal
)
27-02-2003 06:40
sevisehda
If your speaking of an L shaped bumper that pivoted in the bend its been done in the past. Except it was used to lift the agressing bot an inch or so off the ground so it would loose traction while the L bumper equipped bot would gain some.
I still don't see how your going to get suction if theres a gouge in the HDPE.
27-02-2003 08:45
Katie Reynolds
The possibility of gouges on the surface of the HDPE is the reason we didn't use suction cups. We found that even a fairly tiny scratch would weaken the suction so much that even I could pull the cups off with no problem (and I'm pretty weak! ) We tried a number of different things ... everything from gouges in the surface, to little scratches. We used plain ol' suction cups, and we used suction cups with a vacuum. The bottom line: No matter how tiny the scratch/gouge/mark/irregularity on the surface is, the hold of the suction cup will be weakened considerably.
Anyway, your bot looks great guys. Good luck!
- Katie
27-02-2003 10:24
f22flyboy
In defense of suction cups:
Suction cups that mechanically create a vacuum are actually pretty good at handling lateral force. They are the kind that are used for moving large panes of glass. One suction cup independently definitely won't stop 130lbs at 10 fps, but multiple ones, well placed, and backed up with good drive system, can probably stop all but the most powerful (and determined) bot.
edit- the way we tested this - a 160 student did pullups hanging on to 2 suction cups attached to a vertical pane of glass. Probably not the smartest thing, but it proves that they will hold lateral force. Also, multiple suction cups spaced out will minimize the chance that a large scratch will mess them up.
27-02-2003 10:34
sanddragA 220 pound student on our team did pullups on two 4.5" di mechanical suction cups stuck to an enamel painted door jam. Also, I stuck one to the top of my washing machine and pushed it sideways as hard as I could and it would not budge. I even hit it with a hammer too and it didn't really move. There's a lot of science behind suction cups.
27-02-2003 10:42
f22flyboy
you have the same ones we do... good thing you aren't coming to our regionals 
27-02-2003 11:55
SpikeyWe tested a vaccum cup on our robot and it was crazy, we had 4 people pushing the robot and it barely moved!! With two vaccum cups its gonna be really hard to move someone.
We did no use the vaccum cup because of weight but we have two smaller cups that work really well as long as we clean them before a match.
27-02-2003 12:07
Matt Reiland
I hope that teams out there won't be coating the botton of their suction cups with gels or fluids to try to get a better seal, that would get a pretty quick DQ in IMHO.
27-02-2003 15:08
Rook
If a team puts the thought into suction cups, they could be effective. I think many teams probably grabbed a plunger from the bathroom, slammed it down onto the HDPE, and then after watching it easily slide across the top, wrote off suction as an unworkable idea.
My team's fear of suction cups is the unpredictable nature of how much the HDPE will get scractched. We're pretty sure it's going to have some deep gauges from things like omniwheels, robots falling over, totes falling over, flailing arms, etc.
27-02-2003 15:29
pras870
The red tread on the tire is simply the timing belt given out by FIRST. As for the cups, a small scratch in the HDPE should not really matter. We even tested this on a surface of our HDPE which was scratched, and it did not effect it at all. The way the cups are designed, the pressure which is generated is spread out evenly over the base of the cup, for more surface area. We locked them down, created a vacuum, and had half our team try to push it horizontally from side to side and front to back, and it would not budge.
27-02-2003 15:49
evulish
What about dirt on the HDPE...I think that was our teams concern with suction cups (and the pneumatic resources it would use)...the only time I have seen FIRST take care of the field is when the carpet gets unwound. I really doubt they'll be shining the HDPE after every matching.
27-02-2003 15:52
Rob Colatuttoi;d like to know how dirt is going to get on the hdpe..... i'd imagine they make the feild reseters clean thier shoes before going out because that could cause a lot to the rug too
27-02-2003 16:24
Rook
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Originally posted by Nataku i;d like to know how dirt is going to get on the hdpe..... i'd imagine they make the feild reseters clean thier shoes before going out because that could cause a lot to the rug too |
27-02-2003 16:30
pras870
a little zamboni driven by a midget would be funny to watch, and serve a great purpose
27-02-2003 17:32
UlTiMaTeP
I have no doubt that suction cups will hold great. BUT when a bot hits you its not gonna try and pull you up like a potato its gonna try and push you from the side which a suction cup grips straight down.... for example take any suction cup and take somthing flat, stick it on and feel how much force is needed to pull it straight off, then stick it back on and try and slide it, if the surface is flat and smooth the suction will stay intact but you will be able to move it where ever you would like. Which is exactly what is going to happen at KOH
27-02-2003 18:15
Rook
|
Originally posted by UlTiMaTeP I have no doubt that suction cups will hold great. BUT when a bot hits you its not gonna try and pull you up like a potato its gonna try and push you from the side which a suction cup grips straight down.... for example take any suction cup and take somthing flat, stick it on and feel how much force is needed to pull it straight off, then stick it back on and try and slide it, if the surface is flat and smooth the suction will stay intact but you will be able to move it where ever you would like. Which is exactly what is going to happen at KOH |
Moving Glass
Should put away any debate on suction cups. The full weight of the glass pane is being held by the suction cups and its on it's side. I don't think the worker would stand where he is, if those cups weren't safe.
27-02-2003 18:16
Matt Reiland
I have no doubt that there are suction cups that can support huge side loads on them. My Mitsubishi Big Screen was carried into the house with 2 suction cups vertically on each side and they didn't slip. The key here is that it was on a 'prefectly' smooth surface (Glossed Burlwood). People out there that are talking about how glass panels are lifted like this are right, BUT.......... once there are small scratches in the plastic where air can leak past the rubber, your suction is gone it is not the same as glass after the first few pushing matches up there.
27-02-2003 18:27
Rook
|
Originally posted by Matt Reiland I have no doubt that there are suction cups that can support huge side loads on them. My Mitsubishi Big Screen was carried into the house with 2 suction cups vertically on each side and they didn't slip. The key here is that it was on a 'prefectly' smooth surface (Glossed Burlwood). People out there that are talking about how glass panels are lifted like this are right, BUT.......... once there are small scratches in the plastic where air can leak past the rubber, your suction is gone it is not the same as glass after the first few pushing matches up there. |
27-02-2003 18:41
Katie Reynolds
|
Originally posted by Matt Reiland I have no doubt that there are suction cups that can support huge side loads on them. My Mitsubishi Big Screen was carried into the house with 2 suction cups vertically on each side and they didn't slip. The key here is that it was on a 'prefectly' smooth surface (Glossed Burlwood). People out there that are talking about how glass panels are lifted like this are right, BUT.......... once there are small scratches in the plastic where air can leak past the rubber, your suction is gone it is not the same as glass after the first few pushing matches up there. |
- Katie
27-02-2003 18:47
OneAngryDaisy|
Originally posted by Cory wow...those things are humongous. Cory |
27-02-2003 19:02
soezggwell, there are basically 2 ways to use a suction cup.
1: Put it on the ground and suck all the air out of it so it attatches
2: Push down on it and have all the air go out of it creating suction.
the first way is reverseable
the second way is pretty good if you do it right.
admittedly, it is a good strategy for a koth bot, whether it works or not.
good luck.
27-02-2003 19:12
Clark Gilbert
Hmmm
There is another way...
Force it down, and then pull it up.
I've done some research on the internet and there are a ton of suction cups out there, (even rectange shaped). It should be really interesting what teams use this year and how they use them.
27-02-2003 20:12
evulish
The suction cup we had prototyped was made out of a circlular peice of aluminum with a groove in the bottom where a latex O-ring fit. It worked pretty well...untill we stratched up the surface a bit. Still, it wasn't very much for the resources it would use (like 2 of our cylinders) If anyone can make it hold and stay...that's where my money is going. Ohh...and that suction cup sticks to faces...not stomachs. Not that I know this personally or anything.
27-02-2003 20:41
Spikey
Re: Hmmm
|
Originally posted by Clark Gilbert There is another way... Force it down, and then pull it up. I've done some research on the internet and there are a ton of suction cups out there, (even rectange shaped). It should be really interesting what teams use this year and how they use them.
|
I think suction cups will prove to be a determing factor this year.
27-02-2003 20:51
UlTiMaTeP
But back to the point I was trying to make, the amount of force that a bot has going 12 FPS weighing 130 pounds far outweighs what ive seen in the suction cups. I also think that even if a robot that was rammed at full speed into a robot secured with suction cups *IF* they even to withstand that kinda punch, There seals would for the most chances break.
27-02-2003 23:20
sevisehda
Suction cups will work good for the first few practice matches and maybe some into the qualifying but by the time finals hit that HDPE will look like a scratching post covered in dust, dirst, and oil. Everyones pro-suction point is saying they can withstand exert a huge force on a glass-smooth surface, chances are the HDPE will be more like a rough concrete. If teams still want to go with suction cups it seems logical to go with 20 small ones instead of 1 or 2 large ones to minimize the risk of trying to lock onto an area with a scratch.
Do you want to take the chance that during finals your bot trys to lock onto the joint between the 2 pieces of HDPE and another bot knowcks you off like you weren't even there?
Also Ramp-doms have to stay for nearly the entire 2 minuts and even if the scratches only allow a slow leak chances are the ramp-dom would have to re-attach every so often.
The best option is to put some _ _ _ _ _ _ _ _ breaks on the bottom of your bot and get a COF of about 2.0 or if your budget allows and you can find it get some _ _ _ _ _ which will give you a COF of about 3.5.
Friction brakes are more reliable and lighter.
27-02-2003 23:49
OneAngryDaisyJust remember- you have to be on the top of the ramp to use your suction cup...
if you aren't first.. tough luck..
28-02-2003 14:37
|
Originally posted by sevisehda Suction cups will work good for the first few practice matches and maybe some into the qualifying but by the time finals hit that HDPE will look like a scratching post covered in dust, dirst, and oil. Everyones pro-suction point is saying they can withstand exert a huge force on a glass-smooth surface, chances are the HDPE will be more like a rough concrete. If teams still want to go with suction cups it seems logical to go with 20 small ones instead of 1 or 2 large ones to minimize the risk of trying to lock onto an area with a scratch. |
| FIRST expects the HDPE surface to become marked and soiled. The platform will be cleaned occasionally. The frequency of cleaning will depend on the amount of soiling and the time schedule of the matches. There is no guarantee that the platform surface will be clean for every match. |
Also found this
| We will try our best to maintain the condition of the HDPE. There is no schedule for replacement. There is no means for repair. We can keep it somewhat clean. Expect wear and tear. Do not expect a perfect surface for suction cup attachment. There is a seam in the HDPE at mid-platform. Because of the time required to change the HDPE, its condition will be evaluated at mid-day breaks. Spare HDPE sheets will be on site at each competition. The HDPE can be flipped to gain a new surface. We will not be able to determine the the amount of wear and tear that the HDPE will receive until we experience its use in the first week of competition. Do not expect perfect conditions for each match. |
03-03-2003 21:25
Austin
| Suction Cups slide - maybe you haven't been informed, but there are some suction cups out there that are completly immovable, as far as you know the KATS have one on each arm |
03-03-2003 21:40
soezggim liking the idea of suction cups even more at every moment
45's suction cups are sweet. meant for load paralell to the attaching surface, they should hold very well.
04-03-2003 03:29
Katywouldn't it really be from what kind of suction cup you used? If the suction cups had a very large edge to them, spare material they might hold. Think like a dinner plate, the indented area being the suction cup. There is a wide lip around the whole thing, now if that was wide enough, say maybe 3 inches of just extra material where it met the floor it could probably compensate for short 2 inch marks because the extra material would completely cover all the short ones that got under it at all and those that started midway wouldn't have access to the vacuum inside. Our team did not have an opportunity to make an entire ramp top to see how long the usual marks are or how deep they are but I'm guessing they might be deep but short meaning that might be a solution. Dust might be a problem but I don't think many robots will be dumping chain grease everywhere for the simple reason that they would work hard to fix that for the safety of their own electronics panel if nothing else. Any team that didn't wouldn't be playing many matches in which they got on the ramp anyway.
I completely admit this is all in the wonderful world of logic which often has nothing to do with the real world, please tell me how far from reality any of it has gone in your experience.
22-03-2003 22:36
Gusman1188that is a pic. of my teams suction cups and there are two 300 pound suction cups, totaling a 600 lb vacuum. Dont believe me? No robot in two regionals could move us and robots actually bounced off our bot, in fact there so effective that in order to get the robot up at the end, we have to depressurize our pnuematics.
22-03-2003 22:58
pras870
If anyone cares, I must point out, that suction cups is what won the regional at SBPLI, 2 out of the 3 teams used them, ourselves and one of our alliance partners. We would simply go to the top of the ramp, suction down, not be moved, and theres 50 points right there, kinda hard to come back with 1 bot and no multipliers
22-03-2003 23:35
philipprogramer
Easy Way to win against suction cups
I might point out that the only way the suction cups will work is like OneAngryDaisy said you have to make it to the top of the ramp to suction down. In the Florida Regionals we were up against a team with good suction cups but we wouldn't let them get up to the ramp.
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