Robot Speeds

[sanddrag]

Originally Posted by spears312

We had the Andy-mark transmissions on our drive train with a four wheel drive. In high gear, we got around 16 fps in a straight line. Unfortunately, we didn't run it at that speed a whole lot, due to high battery consumption and issue with arm stability in turns. In low we got between 11 and 14 (I think, I cant remember the exact fps off the top of my head).

You got 16fps or you geared for a theoretical free speed of 16 fps? Either way it is pretty high but it is okay since it shifts. If you are geared for 16 fps in high that means you are geared for approx 6.2 fps in low with an Andymark, certainly not 11 or 14, unless you modified something.

As a side note 968's 4 speed is geared for someting like 22 fps in high gear, but those kind of speeds would never be achived in the short FIRST playing field so I don't think they ever use 4th.

[santosh]

We had a single speed gearbox. 1 CIM per a wheel. We did 13 fps with holonomic and expanding drive modules.

[sanddrag]

Originally Posted by santosh

We had ... expanding drive modules.

Can we get a picture of what exactly is an "expanding drive module"? Thanks.

[Jizvonius]

I'm going to have to clarify that speed. 13 fps (...calculated, more like 10-11), but that was only parrallel to the wheels. If we drove 45 degrees across our wheels (straight) we would go about 7-8fps.... and then we put our arm on and got scared of going that fast.

Oh and the expanding module thing...hmmm i think i have an inventor pic somewhere.

found it... an old one though.

also, not in this pic is the driving mechanism for this expansion. you can see it here: http://www.chiefdelphi.com/forums/sh...highlight=1002

There was a piston involved also, but we don't like to talk about it.

[Jeff Pahl]

Approx. 4 fps in low, and I think about 12 fps in high. I don't have the numbers here with me. Single CIM with a DeWalt each side. The drivers were afraid to drive it in anything other than low, so we never put the servos on to be able to shift, just left it in low, due to a lack of practice time. We're going to set it up to shift this fall.

[EricH]

Originally Posted by sanddrag

Can we get a picture of what exactly is an "expanding drive module"? Thanks.

I saw the Circuit Runners' robot at nats (scouted it too as it was in our division) but didn't get any pictures. What happened was they had four omni wheels that slid out of the starting box at the robot's corners. I think the motors and gearboxes also slid outwards. Don't ask me how it worked, but it was pretty cool to watch.

[santosh]

^ thanks
Here are a few links that might give you a better idea of what it is.

Here is a link that shows the drive module, this picture shows it still inside the robot. One module consists of the omnie wheel and its gearbox.
http://www.circuitrunners.com/invent..._1002_omni.jpg

Here is a picture of the overall robot.
http://www.circuitrunners.com/invent...1002_front.jpg
The piston running down the middle of the robot pushes down on that piece it is connected to which is connected to all of the drive modules which causes the modules to pop out. We could move them in and out quickly.

I hope that clarifies it a little better.