Manipulators: Claws vs rollers?

[Koko Ed]

We did pretty good in 2007 so we're gonna try to stick with our claw design as much as possible from that year with some inspiration from our even more successful 2008 bot for the elevator.

[s_forbes]

Originally Posted by IndySam

Either one can be very effective but the most effective one is a manipulator on a robot that gives your drivers plenty of time to practice.

You can have the greatest picker-upper-thingy in the world but if you don't get practice with it the team with the uber-simple one that they have spent many hours driving will still kick your butt.

This needs to be reiterated. Get those prototypes done fast, get your robot built quickly, and drive it around for a few days before you ship it! Too many teams look as though they're driving their robot for the first time on Thursday morning at competition.

The same concept applies to all the other parts of your robot, too. "Testing" is indeed part of the design process.

[pfreivald]

We are prototyping several different tube manipulators, including a simple claw and a 'roller claw'...

We are also making our robot modular, so that whatever ends up working best in practice is what ends up on the field!

[IndySam]

Originally Posted by pfreivald

We are also making our robot modular, so that whatever ends up working best in practice is what ends up on the field!

That's is a great way to go. In fact I seriously doubt we even ship our robot with a picker-up-thingy.

[pfreivald]

It's a lesson I learned in real-life engineering that I forgot at first in FIRST, and then remembered, and now am getting more and more insistent upon...

[jblay]

Ive found that in essentially every game but 05 rollers are best for picking up an object. With rollers you can have a very active control on the object and pick up the object wthout stopping.

[Rob Colatutto]

My personal experience with my teams roller gripper from 2007 was this, too much weight. Its very important to keep the weight down on these, its quite easy to get carried away. One other challenge was to design a gripper structure that was light enough to meet our weight goals and work with our wrist actuator design, but at the same time being strong enough to withstand taking a beating on the field and still grab the tubes correctly. We had a match or two where a robot hit us head on with the gripper out, and then it required some 'tweaking' to get the opening size correct. We also prototyped a few different wheel configurations, and tried many different wheel materials, this was very, very useful.

[Ian Curtis]

A claw doesn't need to require precise positioning. You can make it wider so the driver only needs to drive into the game piece, and the game piece settles into a position where you can pick it up. (granted, this will probably be much harder this year than it was in 2007)

Whatever you do, make it idiot-proof. Not because your drivers are idiots, but because the fewer precision maneuvers they have to do, the more awesome driving (and scoring!) they have time to do.

[Stephen of REX]

One thing we learned whether you use a claw or roller: mount the mechanism on a set of door hinges. That way even if the manipulator takes a hit, it won't deform it will just open the hinge.

[Gdeaver]

With any design remember how high you have to go to reach the highest row. The less mass the better.

[bearbot]

Originally Posted by Stephen of REX

Who has experience using roller type tube manipulators? Like as opposed to a claw, which you have to carefully position to pick up a tube, a design with two rollers seems like it could pick up a tube faster. Thoughts?

sweet idea REX cant wait to see your crazy design this year

[ttldomination]

Originally Posted by Koko Ed

We did pretty good in 2007 so we're gonna try to stick with our claw design as much as possible from that year with some inspiration from our even more successful 2008 bot for the elevator.

Could someone explain the lift in this image? It seems like the ropes simply go from the bottom of one stage to the top of the other, so how does it all go up exactly?

Thanks,
Sunny

[Koko Ed]

Originally Posted by ttldomination

Could someone explain the lift in this image? It seems like the ropes simply go from the bottom of one stage to the top of the other, so how does it all go up exactly?

Thanks,
Sunny

You mean the 2008 bot?
Those are slide rails that are designed for use in a copier drawer were used for the elevator.
Just be warned when using them that they can give out (check out 7:52 into the video. Ironically we won the Quality Award after this happened).

[ttldomination]

Originally Posted by Koko Ed

You mean the 2008 bot?
Those are slide rails that are designed for use in a copier drawer were used for the elevator.
Just be warned when using them that they can give out (check out 7:52 into the video. Ironically we won the Quality Award after this happened).

I'm more curious about how the actual lift was obtained. Like, it seems that the rope runs from the bottom of one stage to the top of the previous stage. How would you pull that up?

- Sunny

[Koko Ed]

Originally Posted by ttldomination

I'm more curious about how the actual lift was obtained. Like, it seems that the rope runs from the bottom of one stage to the top of the previous stage. How would you pull that up?

- Sunny

No rope.Chains moved the mechanism up and down..