VEX version of FANUC type arm for automation been done?

VEX V5 Technical Support UNOFFICIAL Tech Support
#1

I am going to be teaching a unit on automation and am wondering if anyone has created a Fanuc type of arm with VEX. I won’t be adding wheels to the base, it will be stationary. The end effector for the arm will be a simple two finger pincher type device. If anyone has experience or pics would love to hear about it.

Thanks in advance,

Rusty

#2

We built one a few years ago, it still makes the rounds to trade-shows with the VEX booth.

-John

#3

Sounds like fun. Be sure to post your progress.

See this post, which shows Fanuc type arm on wheels:
https://vexforum.com/showthread.php?p=139864
with its link to youtube video.

My brainstorm of pointers:

  • Potentiometers are easier to use for position feedback than optical encoders. You can trade off rotation range with resolution if you want.
  • Worm drive joints have good backdrive prevention; if they are too slow, then use gears to speed them up, but keep the backdrive.
  • Use of springs (Vex latex rubber, or rubber bands) can provide some support for extended joints, but it is more difficult to do well with a multi-jointed arm.
  • Avoid transmission of torque through axles, bolt arms directly to gears.
  • Hinges make very stable unpowered joints. I haven’t yet tried to align a gear center with the pin of an axle to provide a powered joint.
  • Minimum weight of arm by using aluminum, and keep motors toward the base if you can, rather than at the ends of the arms.
  • Use a limit switch, or a bumper switch in the gripper to get feedback of grip strength, particularly if using a double worm wheel gripper.
#4