Fully Integrated Silicone Electromagnetic Actuators for Untethered and Bio‐Inspired Soft Robotics

Electromagnetic (EM) soft actuators exhibit exceptional responsiveness to the critical demands of soft robotics, offering advantages such as high actuation speed, low weight, energy efficiency, and electrical controllability. However, conventional designs require external permanent magnets positioned outside the soft structure, constraining practical applications. This study addresses this limitation by developing a novel class of soft EM actuators composed of a silicone matrix with fully embedded copper coils and small magnets, eliminating the need for external magnets. This fully integrated architecture, enabled by additive manufacturing, ensures operation in unstructured environments, as functional elements are monolithically integrated within the actuator. The actuators function in two modes: attraction, inducing 41.7% compression, and repulsion, enabling 47.6% expansion. These actuators demonstrate key performance such as stretchability (continuous operability after 94% strain), scalability (up to 300%), multimodal operation, wearable compatibility (blocking force of 0.15 N), fast response (>1 Hz), low power consumption (2.8 W), lightweight design (18 g), multifrequency capability, and bio-inspired actuation, wherein compression is achieved through electrical current. These silicone EM actuators demonstrate versatility across several applications, such as flow-regulating soft valves, fluid mixing devices, high-speed soft robots (exceeding the 24 BL/s relative speed of cheetahs), and complex 3D structures for controlled contraction and expansion.