Lifting mecanisms
 

My team is looking at a winch with some sort of telescoping mecanism to get a hook up to the top of the platform.

does this sound logical? and do any other teams have ideas for lifting their bots up on the tower?

Re: Lifting mecanisms
 

Sounds reasonable.

I'd like to encourage teams this year to go back and look at the last two times there's been hanging: 2004 and 2000.

And, a tip from someone who built a robot to play the 2004 game, make sure that you can get your hook out of places you don't want it and then still hang, if you can. (Examples: the floor, another robot's lightening holes (actually happened once in 2004), the bar itself, the ball return, a tower pole...)

Re: Lifting mecanisms
 

You are going to need a lot of power to lift even 70 pounds up there. The process will be slow, you may have a hard time doing that within 20 seconds.

Personally, I have none at the moment. I have gone from pneumatics, to scissor lifts. I'm still considering the best way.

-Rion

Re: Lifting mecanisms
 

2 FPs with a stock gearbox and a 3-inch diameter winch directly connected to them is enough power to get a 130 lb robot up quickly, like inside of 10 seconds. That's hook at the bottom to robot at the top.

I've seen some other fast ways too.

(P.S. We have another CIM motor available this year, for a total of 5 maximum.)

Re: Lifting mecanisms
 

Ok. I withdraw my statement then. Now i need to look into other ways to hang the robot. :D
(I seemed to have over looked the extra CIM... :yikes: )

-Rion

PS. Is that a typo or did I over look the weight change limit?

Re: Lifting mecanisms
 

It's not a typo. Back in 2004, there was a slightly different weight rule: 130 max, battery included (and bumpers, if you really wanted them). It wasn't until 2005 that the current 120 lbs sans battery was introduced. (Either that, or I'm a year late and it was 2003/2004 for the change.) I was basing my estimate on one particular 2004 robot.

And the extra CIM happens to be located in <R52-D>.

Re: Lifting mecanisms
 

150lb would be the number to use this year with full weight bot + 20lb bumper allowance + ~10 lb battery

Re: Lifting mecanisms
 

Ah okay, now I'm not so confused.

Ah see, there is my problem. I am on <R08> at the moment. I am not an extremely fast reader...

-Rion

Re: Lifting mecanisms
 

I preferred a van door motor direct driving a 1" spool, but we don't have that option this year. :mad: It is definitely possible to lift a 150 lb robot with motor(s), just remember to think about back driving when the power turns off at the end of the match. ;)

Re: Lifting mecanisms
 

well my dad mentioned the winch on the front of a 4 wheeler to be possible, we would have to adapt it to a cim motor but it should be able to lift like 500 lbs

Re: Lifting mecanisms
 

One could easily overcome this with a simple pneumatic locking mechanism, or even a passive tension powered lock.

Re: Lifting mecanisms
 

You could also use a worm gear.

Re: Lifting mecanisms
 

You would be surprised at how fast some robots made it up. I remember team 501 had such a swift movement for getting up.

And to echo what Eric said, make sure youe hooks are secure on your robot. A lot of teams lost their hooks before they made it to the bar from collisions.

Re: Lifting mecanisms
 

To bring a little more "training" to the discussion... you just have to look at the maximum power of your motors to determine the absolute fastest you can get a robot up.

Power = Work / Time
Work = Force * Distance
so
Power = Force * Distance / Time
or
Power = Force * Speeeeeeeed

The CIM motors max out at 343W = 252 lbf*ft/s

So the fastest an optimally geared CIM will lift a bot is about 1.5 ft/s. Or you lift in about a second.

Mind, this assume you're instantly at the max power point, no friction losses, spherical chickens, the works. But, lifting your robot 20" in, say, 5 seconds is easily doable if you gear it right. The gearing it right being key. Max power occurs at 1/2 stall torque. But I'd really aim for 1/4 - 1/3 stall torque for your full load, for safety and losses and all that.

Re: Lifting mecanisms
 

Remember that the more you gear down the more time it will take to lift...