High-Force Soft Grippers with Electroadhesion on Curved Objects

Electroadhesive soft grippers can grasp the most delicate objects without damaging them. They are silent, clean, and low power (1 W). Grasping forces can be very high (>15 N with a 1 g gripper), especially with curved objects. Previous models not accounting for object curvature predict much lower forces (< 2 N). In this work, we present the first model for electroadhesion tapes adhering on curved objects. The model shows very good prediction of the holding force, with an error reduction from 80% to 2% compared with previous models not accounting for object curvature. We show that the reason for the enhanced force is that the tension in the curved tape presents a normal component, which pushes the tape against the object, increasing frictional stress. This model expands the understanding of mechanics of electroadhesion including curved objects. The simple yet accurate equations provide a tool to select materials and geometry for the design of electroadhesive devices with dramatically higher holding forces.