Steel measuring tape is an interesting material, in that it's rigid enough to hold its shape when extended, but flexible enough that it gives way under pressure. Scientists have taken advantage of that dual nature in a clever new robotic gripper designed for handling fragile items.
Created by Assoc. Prof. Nick Gravish and colleagues at UC San Diego, the mechanical appendage is known as "GRIP-tape," the word GRIP standing for "Grasping and Rolling In-Plane." It grasps objects of various shapes and sizes between two grippy but compliant triangular fingers.
Each of those fingers is made of a couple of lengths of measuring tape which are laid lengthwise one on top of the other, and adhesive-taped together in that configuration … so they form a single two-layered ribbon that's bent/buckled at the tip of the finger. Two motorized reels – one at either end of that ribbon – roll it in and spool it out as needed.
By varying the direction in which each of the four reels (two per finger) rotate relative to one another, the fingers can be made longer or shorter, they can rotate an item grasped between them, or they can draw that item in or out, conveyor-belt-style. The entire gripper can also roll from side to side and tilt up and down, swiveling on its robotic wrist.
It is hoped that once the technology is developed further, it could be utilized in fields such as agriculture, for picking fruits and vegetables without damaging them. In fact, UCLA's EEWOC (Extended-reach Enhanced Wheeled Orb for Climbing) robot already uses a measuring-tape-based magnetic limb for climbing metal structures.
”We like to look for non-traditional, non-intuitive robot mechanisms," says Gravish. "The tape measure is such a wonderful structure because of its combined softness and stiffness together."
A paper on the study was recently published in the journal Science Advances.
