Tuning the grasping strength of soft actuators with magnetic elastomer fingertips

In this work, we present an approach that uses multifunctional materials to increase the grip strength of soft grippers, while still maintaining the benefits of gripper compliance. Here, magnetic particles embedded in an elastomeric fingertip, or magnetic elastomers (MEs) are shown to increase grasping strength and influence actuation trajectories in soft robotic actuators when coupled with external magnets. Two PneuNet-style actuators with ME fingertips generated up to 45 N of holding force, compared to only 10 N without a magnet. The actuator demonstrated enhanced grip strength while the ME tip was within approximately 13 mm of the magnet. This paper characterizes numerous ME compositions and demonstrates specific applications where MEs expand upon soft robotic actuation methods. Both the opportunities as well as limitations presented by ME composition are discussed at length.