robot arm

[Peter Matteson]

In addition to what Qbranch asked look through the CD media section for inspiration on simple, or complex ways of doing different functions on the arm. You will see several examples of good 4-bars from this year (125, 126, 148, 1902). If you want to look at the telescoping arm this year's best examples were 173, and 233. When it comes to greater degrees of freedom just look through the gallery there were many fine examples.

[lukevanoort]

I would definitely start with something simple like a basic four bar. If you're feeling like a little more height than a basic four bar offers I'd try doing something like 217 and 229 did in '05. Don't try something with many of degrees of freedom like 75, 537, and 1251's arms this year, I speak from experience on this, our robot this year had a 5 degree of freedom arm, and we wasted a huge amount of time making it, and wiring it, not to mention difficulty controlling it. If I were you I'd build an arm with about 2 degrees of freedom maximum.

[Lil' Lavery]

The more details you can give us, the more specific information and higher quality responses we can give you.
Are you interested in a 4-bar linkage? (Or even an 8-bar linkage).
Are you looking at telescoping arms? How about a pneumatic telescope? Or even powering your extension with surgical tubing?
Would it be powered at the shoulder joint? Or would it be powered from the base by lead screw or winch? What about any counter-balacning?

And there are tons of more factors that can apply, and we haven't even reached the actual end-effector yet! Like I said, more info you give us, more we can help.

[team 1094]

you could try a worm gear with a electrical pot system.

[AndyB]

If you are looking at doing a motorized arm, and decide to use a motor like the globe or window motor, you will want to gear it up to get more torque, but you have to mathematically determine the gearing to get enough torque while not sacrificing speed.

Many teams gear up their arms by sticking a small sprocket on the end of their motor shaft and running chain up to a larger sprocket, which is attached to the arm. This is what we are designing for the four-bar linkage we are prototyping this summer.

I have some decent pictures of team 2056, 1902, and 148's arms I believe. If I find them, I'll post them up here.