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Conventional robots rely on motors, batteries and processors to move and react. While effective, these components add weight, complexity and potential points of failure — especially at small scales. Building insect-sized machines that can operate autonomously without electronics remains a significant engineering challenge.
Researchers have now demonstrated a soft robot that moves using only light and material physics. The insect-scale device completed 188 consecutive jumps under continuous illumination, without a single motor, wire or onboard chip. The work highlights a growing field known as mechanical intelligence, where structure and material properties perform tasks typically handled by electronics.
The robot is constructed primarily from liquid crystal elastomers, a rubber-like material that changes shape when exposed to light. According to Interesting Engineering, when illuminated, the material contracts, bending a curved beam structure and storing elastic energy. Once a critical point is reached, the beam undergoes snap-through instability, releasing the stored energy and propelling the robot upward.
As it jumps, the robot briefly casts a shadow over itself, blocking the light source. This allows the material to cool and return to its original shape, resetting the system for the next leap. The entire sensing, actuation and reset cycle is embedded in the geometry and material response, eliminating the need for electronic control.
During testing, the team expected only a handful of jumps. Instead, the robot sustained 188 uninterrupted leaps. It also maintained performance while carrying loads up to 1,700 times its own body weight — approximately 300 milligrams — without functional degradation.
Beyond laboratory demonstrations, the approach could enable distributed, low-cost sensing platforms. Light-powered soft robots carrying lightweight sensors might traverse difficult terrain, including collapsed structures or hazardous environments, while requiring no onboard power supply.
For defense and homeland security applications, such systems could support operations in areas where electromagnetic emissions are undesirable or where electronics are vulnerable to extreme conditions. Autonomous, mechanically driven platforms may offer resilience in high-radiation zones, disaster sites or confined underground spaces.
By embedding control directly into material behavior, the research points to a class of lightweight, self-regulating machines designed to operate with minimal infrastructure.
The research was published here.
