Quote:
Originally Posted by Qbranch
Just as a rule of thumb... motors, because of the small compressor, tend to be faster at actuating manipulators n such, just because of the low cfm of the thompson compressor. We had a pneumatic actuator on our tetra bot... and it did slow us down some.
This year... motor drives on the elevator.... bottom to top (top row score) about 1.5 seconds give or take  |
I would have to disagree. Generally speaking, a pneumatic is faster than a motor. However, in some cases, you're correct. If you don't have any air tanks, you're limited by the airflow of the compressor. Also, if you're firing pneumatics quickly enough, or using a large enough cylinder that you're constantly draining your air tanks, the speed of the compressor comes in to play.
The trick is to have enough reservoirs, and to not use a larger cylinder than necessary.
Another nice feature about pneumatics is that they tend to be really fast when they're not under load, but they also can provide plenty of force. Our grabber can snap open, which is great when we're picking up tubes, but it also holds very strongly. It's difficult to have both with a motor.
And, generally speaking, you can get more power out of a pneumatic per ounce (excluding the compressor), which means a lighter robot, and more importantly, a lower center of gravity.
We used a combination of motors and pneumatics for our elevator this year. There's a minibike motor driving it most of the way, then when we hit the top of our 6' arm, we extend a 12" pneumatic extension, for a total height of roughly 8'. (For those of you who added 6'+12" = 7', we also have the length of the unextended cylinder in there)