Bio-inspired functional recursion enables multi-mode locomotion in a 140-mg morphing microrobot

Abstract

Insects traverse diverse environments by reusing body structures and appendages through adaptable mechanics, an ability that remains a grand challenge for insect-scale robotics under strict mass constraints. Here we present an insect‑scale robot that integrates aerial takeoff and open-loop attitude modulation, terrestrial crawling, water-surface gliding, and electrowetting-triggered controlled immersion within a 140-mg platform, with these capabilities demonstrated as representative open-loop functional tests rather than a single continuous autonomous mission. Moving beyond actuator‑heavy designs, the robot encodes structural intelligence in a single multifunctional morphing frame driven by shape-memory alloy artificial muscles. This morphing body reconfigures to take on distinct roles across diverse environments: it acts as a steering transmission for asymmetric flapping-wing kinematics, a linear oscillator for terrestrial crawling through anisotropic friction, and a deformation actuator that tunes kirigami-inspired footpad gaps for interfacial support and immersion control. Footpad modulation enables active electrowetting, rupturing the water surface at 225 V to achieve controlled immersion and increasing load capacity to 1.7 × body weight. By integrating soft actuation, structural mechanics, and interfacial control into one reconfigurable structure, this work establishes a paradigm of functional recursion, where a minimal physical platform repeatedly reassigns form and function, addressing the fundamental trade-off between operational diversity and extreme miniaturization.