Antagonistic-contracting-enabled high-power-output, wide-spectrum photo-oscillator for multifunctional actuations

Abstract High-power autonomous soft actuators are in high demand, yet face challenges related to tethered power and dedicated control. Light-driven oscillatory motion by stimuli-responsive polymers with remote energy input and control autonomy presents a new design paradigm, but generating high output power density is a daunting challenge, requiring a new material design principle. Herein, inspired by the flight-muscle structure of insects, we developed a self-oscillator based on two antagonistically-contracting photoactive layers sandwiching an inactive layer. The actuator can produce an output power density of 33W/kg, comparable to that of insects and 275-fold higher than other configurations. Such an oscillator allows for broad-wavelength operation and multifunction integration, including proprioceptive actuation and energy harvesting. We also demonstrated high-performance flapping motion enabling various locomotion modes, including sailboat, bi-directional walker, and flapping wing with a thrust-to-weight ratio of 0.32. This accomplishment represents a significant milestone in advancing autonomous, sustained, and untethered actuators for powerful robotics.