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: