Actuator

[crarm]

I am building a movable robotic arm and the arm weighs about 1~2 lbs so would what would I use to lift the arm up and down. I dont want to spend $100+ on a servo that would lift it so what would I use.... an actuator?
Plz help.

[HDL_CinC_Dragon]

Well the amount your going to have to pay depends on how many Degrees of Freedom(DOF) you want your robotic arm to have. Different strength servos/actuators will be needed for different parts of the arm. Describe your arm a little bit better.

example:
"The base can turn 360° on the Y-Axis. The arm can move 90° up and down on the Z-Axis at the base. There is a single elbow that can turn 180° on the X axis and 180° on the Z-Axis. Then at the end is the hand which can turn 360° on the X-Axis at the wrist."

-EDIT-
Axis description when looking from the front:
X: Side to side
Y: Top to bottom
Z: Forward and back

-EDIT-
Sorta like this:

(Click for bigger view)

[crarm]

Well this arm is actually going to have a small rototiller at the end. Its not very big.. its more like a prototype. So i want the base to spin 360. The arm does not have a pivot point in the middle. It is pretty much a bent steel bar. The rototiller will be able to tilt up and down to adjust to differnet ground levels.

[HDL_CinC_Dragon]

Rototillers are not light at all. If you really want to have an "arm" to raise and drop this thing, your going to have to go hydraulic.

[crarm]

The rototiller itself weighs very little compared to the motor that turns it. You don't think we could use an actuator to raise and lower?

[HDL_CinC_Dragon]

Rototillers are typically just a motor with spinning spikes attached to it more or less. Are you saying yours has a motor that is not directly attached to it? Perhaps pictures of what youre trying to do would help

[crarm]

this rototiller is very small. The motor of it is really just a small 7.2 volt socket drill. It has a lot of torque and descent speed. This thing only weighs 1-2 pounds. do you still think we need hydroulics.Do you think we could put a actuator under the arm to lift it up and down instead of having a pivot point on the arm that would take all of the weight. wouldnt it be easier to lift from the bottom than a pivot on the arm.

[HDL_CinC_Dragon]

... so this is an electric rototiller?... are we talking about the same device here?
http://www.gardenlines.co.uk/CMS/Uploads/Products/Ardi%20Badger%203365%20L.jpg

[crarm]

umm..... no. think of the rototiller as the size of a pop can with blades. the actual base of the robot is 4"x12"

[HDL_CinC_Dragon]

Im confused... picture.

[Admin]

http://www.societyofrobots.com/robot_faq.shtml#robot_arm

[crarm]

We dont have any pictures because we havent built it yet. but we did buy some actuators some i think we are good for now.

[HDL_CinC_Dragon]

I mean a picture of the rototiller. Or are you building that also? Perhaps a picture of something similar?

[crarm]

Right now I'm at school but once i get home ill put a picture out here so you can critique it.

[crarm]

Heres a picture of the rototiller part of it.

[DC-Electronics]

I hate to be a salesman, but the motors im currently selling for $15 each would likely do the trick

http://www.societyofrobots.com/robotforum/index.php?topic=6766.0

[crarm]

Any more suggestions?