Self-Sustained, Continuous Jumping of a Light-Driven Electronics-Free Insect-Scale Soft Robot.

Abstract

Insects scavenge energy from the environment for self-sustained operation, and some species use repeated jumping to traverse varied terrain. Such capabilities are desirable for surveillance, disaster recovery, environmental monitoring, and hazardous environment exploration. However, insect-scale (sub-gram) robots are typically limited to few jumps due to inefficient integration of energy, actuators, and control. Here, insect-scale (301 mg) soft robots capable of continuous, autonomous jumping with energy harvesting, actuation, and control embedded in their physical structure without electronics are introduced. Powered by constant light, a single robot achieves 188 nonstop jumps and accumulates over 800 jumps in a year without diminished performance. This behavior is enabled by self-sustained, repeated snapping (SSRS), a light-driven mechanism from a self-shadowing-induced feedback loop based on dynamic light-material interplay. The SSRS exploits snap-through instability and self-shadowing of photoresponsive liquid crystal elastomers (LCEs), enabling untethered, perpetual actuation, and the snapping dynamics are investigated through simulations and experiments. Beyond sustained motion, the robot demonstrates self-righting, directional jumping, obstacle negotiation, hazardous gas sensing, and extreme load-bearing (≈1700 times its weight), highlighting potential for disaster recovery, confined-space exploration, and environmental monitoring. This work advances insect-scale robotics toward fully autonomous, long-lived micro-robots.