Risk of the Lift?
 

With this years game there are two main ideas of how to get the robot up either four inches or twelve inches. They are by ramp or by lifting. For those that are lifting and for those that plan to either climb or be lifted, I believe that the lift is much more dangerous. Although with the ramp you have to to keep it in your base and with 2" of clearance due to bumpers you will need to have a small angle thus a longer ramp, it is much more safer. Your robot is always on solid ground. With the lift you are in the air. Are you sure 30 points is worth the risk of your robot falling twelve inches off of the ground? Although I hope this never happens, I think before teams start thinking of being lifted that they should all consider the possibilities both positive and negative. The main one is a robot falling, and today when my team was discussing this I thought of the fact that if you are being lifted up, you are no longer in control of your robot, and that if anything happens your robot will fall. What if it does? Will your team build a more robust robot that can take a twelve inch fall? Will your team prepare for a worst case scenario?

Before you answer keep in mind that six hard weeks of planning, designing, and building went are going to go into your creation.


Pavan.

Re: Risk of the Lift?
 

Yuu forgot another idea of lifting...
Both a Ramp and a lift, meaning either a robot will be gping up a ramp and then lifted, or one bot goes up a ramp, and another is lifted using an arm...

There are many fine ideas...be sure you think of as many as you can before you decide what you build nd what strategy you are gonna use.

U could also build your bot witha safe lifting system. Its FIRST, everything is possible here. You may even build a chopper :)

Re: Risk of the Lift?
 

I am just asking the robots that are going to be lifted, if they know the risks and I am more so asking them if they are prepared for the consequinces of their choices.

Pavan.

Re: Risk of the Lift?
 

I see what u r asking..
But u make is sound is if each and every liftins system in the game is going to be hazardous, and it will be so in osme cases, but some of them are gonng abe very safe, with not a big risk at all, bout the same risk as there was last year climbing a ramp, maybe even smaller...

I personnaly thing that 30 points are a lot and that it can cahnge the match from side to side...expecially if it's gonna be 60 points =]

Re: Risk of the Lift?
 

And then, at the end of the match, the drive teams who are being lifted all say at once (in a GOVERNATOR voice)- "GET TO ZE CHOPPER!!!"

Re: Risk of the Lift?
 

In order that robots who want to be lifted at the end of a match, someone should come up with a specification for a standard lifting attachment. This way, teams may design a lifting mechanism that other teams can design for.

Re: Risk of the Lift?
 

ROTFLMAO!

Nice.

Re: Risk of the Lift?
 

ramp = safe
lift = dangerous
bottom line
also in order to accomodate two robots on a platform it would have to be between 36 and 38 inches wide and 80-86 inches long. This would accomodate for robots with wheels along the short or long sides.

i think we got it. I designed it in inventor and have made a cardboard mach up and today I'm building a half scale model to show at the meeting tonight.

wouldn't 60 points pretty much change the match outcome in most situations?

Re: Risk of the Lift?
 

There are really three methods.

Ramp
Lift from above
Lift from below

I can see lift from below being dangerous because your centre of gravity is above the lifting point and toppling is an issue, but lifting from above should be safe as long as your attach point is solid and they aren't lifting you with silly string.

Ramps are only slightly less dangerous from a toppling perspective. Maneuvering onto a 3ft wide ramp at low speeds will be very difficult for many robots because a motor might stall and all of a sudden they spin and fall off. You can't go at high speeds because you'll damage the lifting robot and also probably fall off. If either your drivers or the rampbots drivers bump their controls, you can easily topple off.

If you're 12 inches off the ground on a ramp, you're just as far up as on a lift. That's just as much robot-destroying potential energy. In either case an accidental movement of either robot might topple you. If you're lifting from above, with a chain, even the lifting robot jiggling might be safe since you you just sway. The lifted robot could do whatever they want.

There were plenty of robots in 2004 that chin-upped without incident despite other robots competing for limited chinup space. Many of them got substantially higher than just 12 inches.

Re: Risk of the Lift?
 

Good Points, Maybe all teams should consider putting a victor brake function in their programming and controls? Just a thought

Re: Risk of the Lift?
 

Hmm, You must have been watching a different competition than I was last year. The number of teams that couldn't climb the ramp surprised me. The number of teams that tried to climb the ramp and fell over astounded me.

Re: Risk of the Lift?
 

It is almost going to be impossible to use a lift to elevate your alliance's robots. It is going to be impossible because pneumanic cylinders are not going to give enough force to exert a lifting device.

Re: Risk of the Lift?
 

Now i dont know if this idea is good for use.. But what if you had a bar extend from the "lifter" robot on both sides, and other robots had their own lifting mechanism that would pull themselves up? it would be like 2004, execpt you must make it at least 12" of the carpet.

Re: Risk of the Lift?
 

The only problem is if only one hangs, then they will both tip unless you have a way to stabilize yourself

Re: Risk of the Lift?
 

This is very true.. that is why team 118 had 2 arms on our robot chainzilla during the 2005 competiton. We had noticed after getting a certain height off the ground that more weight on one side made the robot tip over more so we added a second arm to balance the weight and always made sure that both arms had a tetra on them.

Re: Risk of the Lift?
 

I don't think we can determine which method is more dangerous since you can't know exactly how those two options are being accomplished. But if someone messes up their bot driving up a ramp it's their fault, which could be a different story with a lifter, so I'd opt for the ramp.

We've been thinking about a ramp that has a sort of jack underneath it to level out the ramp and raise your ally's bot. I see this as a combination of the two methods.

Re: Risk of the Lift?
 

I think the practice fields will be full of teams praticing lifting to lower the risk. It would be nice if at the regionals there could be the practice field and then also an extra spot of carpet that the teams could practice lifting on.

Re: Risk of the Lift?
 

That sounds good on one condition. A big sign that says "Weight Room" must be placed somewhere nearby.

Re: Risk of the Lift?
 

I wasn't refering to the ramp of last years competition. If you had a more shallow grade on your ramp it is easier to get onto. Also a ramp wouldn't require the counter balancing that would come with lifting a robot.

Re: Risk of the Lift?
 

Of course, however a lot of teams couldn't climb the ramp last year because on low ground clearance. I am just trying to point out that these robots are/should be built to take a beating, fall over, etc. A ramp is not always "safe" and even a 12" fall shouldn't be the death of a robot.

I think you should broaden your thinking about not cantileaverd lifts. ;)

Re: Risk of the Lift?
 

Well they don't tell you to build the robots hardy for nothing.
In 2004 I saw robots drop from five feet and still manage to survive and function (after some repair work) one even went as far as the final four after it dropped from the bar. Unless you built your robot out of porcelin I don't think a one foot drop is all that big a deal.

Re: Risk of the Lift?
 

Right but by making the angle more gentle you eliminate the ground clearance issue as well.

Re: Risk of the Lift?
 

last year, people knew the ramp would be there, and they still weren't able to get up. this year, the ramp isn't actually a game element, so people will be even less likely to design enough torque, or a low enough cg. also, the ramp will probably be pretty narrow. i know that when running from across the field, with 10 seconds left, there is almost no way to make it to the ramp, get aligned, and get up in time.

Re: Risk of the Lift?
 

True enough. Most people wont be sitting in the home zone with like 30 secs left in the match to be sure someone knows there set up for the whole ramp thing. I think I lift would be much faster if pulled off right. As I posted in another thread A forklift can lift a lot more than its own weight with no worry of tipping, and even if there was a chance build safety arms or something on the side so at most the robot tips a bit and wont fall off. One foot isn't much so anything is possible really.. it will depend on the situation. but a lift is do-able.

Re: Risk of the Lift?
 

I predict you'll be mighty surprised when you go to regionals and see many successful lifts ;)

Re: Risk of the Lift?
 

What difference would it make if you never even left your home zone from the very beginning of the match and just sat there the whole time ready to lift your two partners? It's not like the opposing alliance can do anything about it. You can't try to block a "bot lift" because you have to vacate the opponents home zone starting 20 seconds from the end anyway.

Re: Risk of the Lift?
 

On Galileo at Nationals during FIRST Frenzy, there was a robot suspended in the air, as high as the bar, 10 feet. The entire robot fell off the bar (yes, it fell all ten feet!), landed on polycarbonate and somehow managed to survive. Teams just have to take careful consideration when designing their robot. If you plan to drive up on any other robot, or lift other robots, you have to take the risk factor into consideration.

Also, I think thats the risk that it takes when deisigning any robot. This is what makes the game more interesting to watch.:cool:

Re: Risk of the Lift?
 

alright i'm signing out of this argument 1741 has its methods don't you worry.

Re: Risk of the Lift?
 

True enough. But how many robots are going to be sitting there at that time is what I'm trying to say. How many times would like a robot to sit there the entire match just so you can get on it in the last 15 secs? I mean it will be done, i wasn't saying it wouldn't, all I'm saying is it will take time for the ramp to get set up.

Re: Risk of the Lift?
 

If your robot cannot survive a 12" fall or a tip over onto it's back or side, you need to build it a bit better. That's my opinion. Robots will inevitably fall with or without platforms/ramps.

Re: Risk of the Lift?
 

This is my personal apology for my "attitude" earlier. Turns out after crunching the numbers lift = lighter than ramp. So drum roll please 1741 is.......lifting!! We'll see how it works. I do have a question. If we were to use honeycomb (the metal used for certain surfaces on comercial air craft) and used glue to attach the skin is that within the rules? As they read it says that you may not use adhesive back tapes, but this isn't tape so I think its legal but I wanted other opinions if you wouldn't mind.

Thanks

Re: Risk of the Lift?
 

remember last years ramp was pretty steep and also made out of diamond plate neither of which are requirements for anyonesramp

Re: Risk of the Lift?
 

IMO, if done correctly, a lift can be just as safe as a ramp.

Re: Risk of the Lift?
 

You could technically have a pneumatic lift that lifts your own bot so another bot can drive undernieth then you could raise your lifting mechanism thus you are off the floor!!!!:cool:

Re: Risk of the Lift?
 

Wouldn't it damage the other robot thus no alliance parter would want to drive under you and most offensive teams will have an arm or manipulator that is at least 3 feet high.

Re: Risk of the Lift?
 

Yeah, and the weight issue:ahh: is a biggie there too...

Re: Risk of the Lift?
 

Yeah there's a big risk with that stragedy. This will only work if teams design has a large flat area with no appendages sticking out. Also if your arms were to give before your partner was fully in position the fall could cause huge damage to the front of a robot. Also unless other robots are benching 100-120 lbs...

Re: Risk of the Lift?
 

It is almost going to be impossible to use a lift to elevate your alliance's robots. It is going to be impossible because pneumanic cylinders are not going to give enough force to exert a lifting device.

im pretty sure that the pneumatic cylinders come in larger sizes than they gave us so i think it will be possible to lift other robots with a lift. and i thin the largest size is a 2 inch cylinder.

Re: Risk of the Lift?
 

Good point. I think many people would overlook the possibilty of being dropped if planning on being lifted instead of the one lifting...

:]

Re: Risk of the Lift?
 

if they are planning on being lifted they might design the robot so that it can take a little more impact from the bottom (if dropped). But if the lift is designed correctly it probably won't be likely that it will drop a robot. Teams will take the risk into consideration and make it efficient because they wouldn't want to be dropped either.

Re: Risk of the Lift?
 

Thanks for letting out our secret!!!! Just kidding... At first our team went unanimously for the ramp, then the vote flipped and I was stuck on the ramp. Now, well I still think a ramp is going to be lighter, safer, and easier to build, but a lift does have its advantages. So I guess it's official that our team (1741) is lifting...

Re: Risk of the Lift?
 

hi my name is Matt and I think that if you have 1/3 of the robots w/ramps that they will be more valuable than others. I also think that if you have a bot that can be like a tank or a blocker and or some how create a robot with a arm that sits stationary in between your rings and the spider rack and with a pivoting arm meaning that if you create an arm that rotates 180 to 270 degrees that I think would also be valuable
:)

Re: Risk of the Lift?
 

In 2004 team 1141 had 4 pneumatic cylinders (one at each corner of the robot) that lifted them 1 ft so that their 9ft arm could grapple onto the bar. This allowed them to make it geometrically impossible for the robot to not be high enough. So the stock pneumatics CAN lift a robot.

Re: Risk of the Lift?
 

Cmon man you gotta put up a better argument than broad statements like "its almost going to be impossible..." or "im pretty sure..."...If you think teams cannot be lifted with pneumatics, you might wanna scroll through CD-media back to 2004 where quite a lot of teams used pneumatics to lift there 120lb+ selves............VERY SUCCESSFULLY

Get creative...impossible is a dangerous word my friend

Re: Risk of the Lift?
 

Why are you limiting yourselves to pneumatics? There are MANY more options that would work just fine.

And I would agree, things that were impossible 10 years ago are now old news.

Keep the good ideas coming.

Re: Risk of the Lift?
 

Why can't pneumatics lift? We used a 2-inch cylinder in 2004 to lift our robot and that was pulling. If you look at the math that 2-inch cylinder (the actual piston was probably smaller, lets say 1.5 inches) has 7 square inches of pushing power. At 60 psi that means that cylinder has 424 pounds of force. Now lets lower that estimate some for efficiency and put it at a mere 300 pounds just for fun. That means that with the number that our team currently owns (two) we could lift 5 robots off the floor to a height of about 3 ft. If we didn't lift us then with two we could lift every other robot on the field. They have more than enough power to lift your entire team.

However, I don't think that would be the way to do it cause that takes a long time to charge up for (and more than all of the storage that we got). I think a motor winch would be better suited. Also why is a lift more dangerous than a ramp? When rolling up a ramp the robot is moving on a very narrow surface and might drift without the driver being able to tell. When a lift is working then all of the force is vertical, that robot only moves up and not laterally (hopefully). No lateral force result in no lateral motion and so how does the robot topple? If the lift is done well I bet that it’s safer than a ramp cause it can be better automated.

Just a couple of thoughts

Re: Risk of the Lift?
 

While yes there is a danger in the lift, dont forget we were jumping off a foot tall ramp last year.

Re: Risk of the Lift?
 

While both the ramp and the lift have their dangers I think the ramp is a little more dangerous to the robot being climbed specifically if there is a arm or tube manipulator it. This can be prevented a little easier with something to keep the lifted robot from swinging into you.

Also, as far as pnuematics being too weak to lift a robot, (which, as its been said they are not) there is nothing ruling against aiding the piston(s) to lift a robot, such as gas springs or a pulley reduction;).

Re: Risk of the Lift?
 

The problem I forsee with pnuematics is volume of air, and weight of the system. There is the Bane Bots Transmission that is a 128:1 ratio. That my friends is serious torque. Also in regards to lifting, It would almost have to be done with a non cantilievered lift because you just won't have the counter balancing ability when you (a 135 lb robot) are lifting another 135 lb robot. Do what you will we are in the process of building our lift system this weekend I'll let you know if it works or not.

Re: Risk of the Lift?
 

why lift from above when you could just use something as easy as a ramp where there is no chance of tipping

Re: Risk of the Lift?
 

You may want to look at the math AGAIN. The cylinders are rated on the actual piston diameter, so a 2" cylinder has a 2" diameter piston. When you do the math, a 2" piston has a surface area of 3.14 square inches. At 60 psig, this equals 188 lbs. of lifting force. In addition, I believe the longest stroke you can get is 24". You are correct that these things require a LOT of air volume. We used a 2" x 24" to lift ourselves in "Raising the Bar" and it took a good 30 seconds to get us all the way up.

Re: Risk of the Lift?
 

The 2" Bimba cylindar has a push factor of just over 3. So 60PSI in the cylindar will provide just over 180 pounds of pushing force :cool: . In other words, a single 2" cylindar has the pushing force to lift a robot.

Believe me, there will be a LOT of successful lifts.

As far as which is safer ... both are just as safe. The same amount of energy will be in either design because you are raising the robot the same height. Damage occurs only when that energy is expended (IE a robot hits the floor). The difference is who's in control of the robot at the time of an accident :ahh: .

Re: Risk of the Lift?
 

The ramp was angled more off the ground last year. This year we have the option of making the ramp relatively flat.

Re: Risk of the Lift?
 

Last year the ramp angle was known and robots were designed to climb them (and still many failed). This year, if an alliance robot has a ramp, the angle will not be known, the width may, or may not be sufficient, and some robots will not be designed to climb a ramp. Last years ramp was a solid unmoving structure, this year (if a robot has a ramp) it will be mobile, and probably flex under load. Remember, the longer you make it, the more structure it needs to support the weigh. Lets hope people dont weight reduce structural members.

So even a 'relatively flat' ramp may prove to be a difficult (if not impossible) obsticle.

Re: Risk of the Lift?
 

All I know is that at the competition I know there has to be an alliance where one robot will go onto another robot and then that robot will try to lift the other and then all three will flip over and the whole regional will go quiet while this happens. Oh and the pit area is going to freak out with the silence too probably.

Re: Risk of the Lift?
 

My nightmare begins with a rookie team driving up our ramp full speed and crashing into our ringer arm. Ramps give me grey hair....oops, all my hair is grey as I type.

Ken

Re: Risk of the Lift?
 

I had an interesting thought. Lets say that my team has two independently lifting platforms set up so that the other two alliance members can drive on and be lifted when they are safely on and stop. Would it be worthwhile to have the other two alliance members hit the disbale button when they are on so they don't accidentally drive off and give us a reputation as a robot dropper.

Re: Risk of the Lift?
 

The strategy when you go with a lifter(or ramp, just call it a +12" bot) is that you want to get picked is my take. So you need to prove in someway that you're an awesome +12" bot. Ideally with a good design, despite alliance drivers errors you should still get a chance to be picked... but lots of teams have (poor) picking processes based entirely on reputation/record so I think you're right that track record is going to be really important.

1817 is going with a +12" bot this year and we have been wondering the same thing about the disable idea. Ramp or lift either way, I expect to see alot of robots try to descore themselves by operator error. I've been wondering how well other teams will take to the idea that we are asking them to disable themselves. :confused:

Re: Risk of the Lift?
 

Its even worse than that. That 2" cylinder can hold 188 lbs - it cannot lift 188 lbs. We have done experiments on "Pneumatic Power" and I presented this at the National conference last year.

Re: Risk of the Lift?
 

Could you be more specific with what teams can expect then for lifting? 1/2 of 188lbs? 1/4 of 188 lbs?

Just some ball park estimate because I think alot of teams did the math and came up with 188lbs and rejoiced (we did). If this isn't what they should expect then I think i'ts important you get information out there. :ahh:

Re: Risk of the Lift?
 

Our experiments showed that a typical cylinder under load could only "Move" between 80 to 85% of it theoretical maximum force. This is probably due to frictional forces in the cylinder and the rest of the mechanisms it was driving. There is also the affect of the transmission of pneumatic energy through the small hoses and valves.

This is no different than motor driven systems. Think of how the efficiency of a gear box reduces the actual transmitted power in those systems. We have learned to not expect 100% of the motor's torque to drive the final system. Another way to think of it is that we do not expect a motor to drive a system at its stall torque - it can hold that much torque - thus the term stall. It cannot drive at that torque. The analogy is that a pneumatic cylinder "stalls" at the rated max force. But it cannot move anything with that much force. And of course the inefficiencies reduce what force it can move.

Re: Risk of the Lift?
 

I thought there was something fishy about my math. I didn't care that much cause my team HAS used this cylinder in the past to lift our bot (one just one, not two or three but one, and it was even in the pulling orientation). It can lift a 130-pound bot.

The problem we had was that it used our entire air storage to retract the cylinder half way and then there was a wonderful time period when the robot would inch up as the compressor slowly lifted the robot off the floor. I would strongly suggest teams don't use this option unless it is the only pneumatics they use. These cylinders just use too much air. Our team is going to use motors to raise our lift and pneumatics is going to be used in very small operations (like latches and so on...)

Re: Risk of the Lift?
 

I think the best thing to do would be to test your ramp with last years robot, or with a human being on a cart (some kind of a test object)

Re: Risk of the Lift?
 

Amen pull last years bot out of moth balls set it up just like you are planning on having the other robots doing it and give it a try. Worst case scenario you drop a robot you probably won't ever use.

Re: Risk of the Lift?
 

Personally, I think people should go with what they want. If you play it safe all the time, you'll never get anywhere. You have to take risks once in a while, even if it's a good outcome or a bad outcome. just be prepared for anything and everything. If you worry about everything too much, that could hold you back. So just take a risk and get through it. Dont ever give up. Thats just my opinion.