Manipulators: Claws vs rollers?

[Wayne TenBrink]

We looked at a claw and a gripper, and made quick ptototypes of each. We are going forward with a claw, but not everyone has full confidence at this point.

A claw is a lot simpler and the parts that are exposed to damage (extended) are easier to fix or replace. It is lighter. A claw can't rotate a tube after picking it up, but this year most or all tubes will essentially be horizontal on the floor. We can do any necessary rotation with the arm. A claw can be made to pick up a tube that is in contact with the robot - and robot/tube contact should orient and locate the tube for pickup. A claw requires fewer wires running out to the tip of the maniplator. It is easier to modify the details of a claw (grip materials, length of the fingers, amount of clamping, etc. Hopefully, our claw will be done soon enough to build a roller claw if it doesn't work!

I expect the tubes to be inflated quite tight. Inflation pressure really changes the dynamics of the pickup. Whatever you use, be sure it can be adjusted for, or is relatively unaffected by tube pressure.

Finish early - then practice, break it, improve it, repeat.