A soft robot has no problem moving with no motor and no gears

What they built — and why it turns heads

Princeton engineers have 3D-printed a soft-rigid hybrid robot that flaps and reconfigures itself without a motor or external pumps. It’s part origami, part polymer chemistry, and part clever electronics: liquid crystal elastomer (LCE) zones are patterned to bend on demand, and flexible printed circuit boards are embedded directly into the print to heat tiny hinges. The team, led by Emily Davidson and Glaucio Paulino, published the work in Advanced Functional Materials and showed a crane-like figure that flaps its wings when selectively heated. It has been reported that the demonstration video was sped up 40×.

How it works — folding, molecules, and micro-heaters

The trick is control at multiple scales. Davidson’s customized printer lays down LCE with controlled molecular orientation so different zones contract predictably when heated. Those patterned contractions act like programmed hinges — origami logic built into the material itself. Instead of glueing on wires afterward, the group printed flexible circuit boards into the structure, using embedded heaters and temperature sensors to perform closed-loop actuation. Precise local heating drives motion, not gears or motors.

Durability, programmability, and the emotional payoff

According to the paper, the device can repeatedly move and return to shape without noticeable wear — a key sticking point for soft robots. It has been reported that the researchers demonstrated real-time programmable sequences and repeated cycles with little degradation. That’s the emotional moment: a delicate paper-crane silhouette that keeps coming back to life, again and again. Cute? Yes. Practical? Potentially. Think drug-delivery devices that bend on schedule, or exploratory bots that squeeze through tight places without heavy hardware.

Why this matters — small steps, big possibilities

The research doesn’t mean motorless soft robots will replace servo-driven machines tomorrow, but it tightens the toolbox. Co-designing LCE printing with manufacturable flexible PCBs simplifies fabrication and could lower the barrier to more robust, autonomous soft machines. Allegedly, the integration is what makes these devices feasible beyond a lab demo. The next moves will be packaging, power management, and biocompatibility — real-world hurdles, but ones this approach seems poised to tackle.

Sources: princeton.edu, Hacker News