This lightweight gripper, which acts like a thumb-index gripper, is suitable for handling food in the food industry, capturing debris in outer space or being incorporated into prosthetic hands.
Jun Shintake, doctoral student at EPFL, said: "This is the first time that electroadhesion and soft robotics have been combined together to grasp objects."
The electrode flaps consist of five layers: a pre-stretched elastomer layer sandwiched between two layers of electrodes, plus two outer layers of silicone of different thickness. 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 interdigitated electrodes, which look like two combs fitted together, create an electrostatic field that causes electroadhesion.
When the voltage is turned on, the electrodes bend towards the object to be picked up, imitating muscle function. The tip of the electrodes act like fingertips that gently conform to the shape of the object, gripping onto it with electrostatic forces. These electrodes can carry 80 times its own weight and no prior knowledge about the object's shape is necessary.
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 able to handle flat or deformable objects.
