Motor-free hip exosuit via high-output fibrous dielectric elastomer actuators.

Exosuits can assist gait and reduce fatigue for both healthy and pathological populations, yet their bulky, rigid actuators (usually motors or pneumatic actuators) hinder natural, comfortable movement. Dielectric elastomer actuators (DEAs) provide a lightweight, compliant alternative, but are constrained by insufficient force, energy output, and integration challenges. Herein, we propose a motor-free hip exosuit driven by high-output fibrous DEAs, offering a previously unexplored paradigm for lower-limb assistance. We develop high-aspect-ratio fibrous DEAs that deliver high blocked stress (381.6 mN·mm-2), energy density (260 J/kg), and power density (1,664 W/kg), enabled by a dual-polar molecular design of the elastomer to overcome the intrinsic trade-offs between dielectric and mechanical properties. A Lego-like integration strategy is established to efficiently bundle fibers for force amplification. The resulting exosuit reduces the walking metabolic cost by 13.9% compared to no assistance, surpassing most hip exoskeletons. These findings advance DEAs toward practical wearable robotics for real-world human assistance.