From Coil to Rotation: A Bat-Inspired Light-Driven Soft Robot with Self-Sustained Oscillation
Self-sustained oscillation in soft actuators enables autonomous, untethered robotic locomotion, yet existing light-driven systems suffer from low oscillation frequencies, rapid photothermal degradation, and reliance on external controllers. This work presents a bat-inspired soft robot that converts continuous near-infrared (NIR) irradiation into sustained rotational motion via a coiled MXene-based liquid crystal elastomer (LCE) actuator. The actuator integrates Ti3C2Tx MXene nanosheets as photothermal converters within an LCE matrix, achieving a photothermal conversion efficiency of 78.3% and a steady-state temperature of 142 °C under 1.5 W cm−2 NIR (808 nm). The coil geometry induces a self-shadowing effect that generates periodic light exposure, producing autonomous oscillation at 2.7 Hz with an amplitude of 45°. The robot demonstrates a rotational speed of 120 rpm and a specific power density of 3.2 W kg−1, outperforming previously reported light-driven oscillators by a factor of 2.5. Under continuous operation for 10,000 cycles, the actuator retains 92% of its initial oscillation amplitude, with a degradation rate of 0.008% per cycle. The bat-inspired wing morphology enables directional rotation and obstacle avoidance in confined spaces. This platform eliminates the need for external modulation, offering a scalable route to autonomous soft robotics for inspection, environmental monitoring, and micro-manipulation.