Robotic fingers to pick fragile objects with a gentle touch

London: Scientists have developed a new soft gripper that uses a process called electro-adhesion and picks up fragile objects of arbitrary shape and stiffness -- like an egg, a water balloon or a piece of paper.

Have you ever rubbed a balloon on your hair to make it stick to the wall? This electrostatic stickiness called electro-adhesion may change robotics forever, say researchers.

“This is the first time that electro-adhesion and soft robotics have been combined together to grasp objects,” said Jun Shintake, doctoral student at the Swiss Federal Institute of Technology (EPFL) in a paper that appeared in the journal Advanced Materials. 

In comparison, other soft grippers are either pneumatically-controlled or fail at picking up fragile objects without telling the gripper beforehand about the object's shape. 

They also have been unable to handle flat or deformable objects.

“The novelty of our soft gripper is the ideal combination of two technologies: artificial muscles and electro-adhesion,” said Dario Floreano of EPFL. 

“Our unique configuration of electrodes and silicone membranes is what allows us to control the bending of the flaps and the electrostatic grip,” added Herbert Shea of EPFL.

How it mimics muscle function and grips onto objects is as follows:

The electrode flaps consist of five layers. 

When the voltage is off, the difference in thickness of the outer layers makes the flaps curl outwards. 

When the voltage is on, the attraction between the two layers of electrodes straightens out the membranes. 

This straightening of the membranes from a curled position mimics muscle flexion. At the tips of the flaps, the electrodes of each layer are designed for optimal electrostatic grip. 

“These electrodes, which look like two combs fitted together, create an electrostatic field that causes electro-adhesion,” the authors noted adding that the object is then picked up using this adhesion.

The lightweight gripper may soon be handling food for the food industry, capturing debris in outer space or incorporated into prosthetic hands.