Gripper device using shear-controlled dry adhesive film

Stanford researchers at the Cutkosky Lab have patented a low cost, passively activated gripper that can grasp large curved, textured or delicate objects using an adhesive film. This film employs dry, gecko-inspired fibrillary adhesives that are able to grasp convex objects almost exclusively by shear force when tension is applied. The adhesion is then easily turned off to release the object when the tension is removed. It is like a reusable, non-tacky tape that only sticks when pulled.

Because the adhesive operates by shear force rather than normal forces or friction, it can grab delicate objects without excessive pressure. This technology could enable a variety of applications that were previously unfeasible, including: transporting objects on steep conveyor belts; robotic gripping for a range of geometries, even geometries that change (like a water balloon); or catching thrown items without active control.

Gripper in action. Objects picked up and placed by a robotic arm using the shear adhesion gripper include a roll of packing tape, PVC tubing, a basketball and a five gallon water bottle. The lower series of pictures shows the gripper catching a thrown ball, including the moment before contact and the catching mechanism.

Stage of Research
The inventors have implemented the gripper device on a robotic arm and demonstrated its ability to both grasp a range of objects and catch/throw items without active control. The objects tested included a tossed ball and a partially filled Ziploc bag.

News Article
Grippy not sticky: Stanford engineers debut an incredibly adhesive material that doesn't get stuck Stanford Report May 27, 2015.