Inch by Inch, This Robot Is Powering a More Energy-Efficient Future for Soft Robotics

A close-up of the eViper soft robot. (Photo by Bumper DeJesus)

Researchers at Princeton have created a soft robot that’s lightweight, flexible, and highly energy-efficient. Unlike traditional robots, it doesn't rely on legs or rotating parts to move. Instead, it uses special actuators that transform electrical energy into vibrations, enabling it to wiggle its way forward—all while consuming just one watt of power.

This innovative device represents a fresh direction in the design and power systems of soft robots, which rely on flexible bodies rather than rigid structures to perform tasks and navigate their environments. While soft robots show great promise for applications ranging from medical procedures to space missions, their unique construction presents distinct engineering hurdles not found in traditional robotics.

The robot operates using the piezoelectric effect—a process that converts electrical energy into mechanical motion through precisely timed pulses. One pulse causes the robot’s soft body to bend in one direction, while another bends it the opposite way. By combining this with cutting-edge power electronics, embedded sensors, and control systems, the researchers built a fully untethered soft robot with energy efficiency on par with that of land animals. Named eViper, this agile, wriggling robot could pave the way for more energy-efficient robotic systems to meet the growing demand of the future.

“Future robots must be highly energy-efficient,” said Minjie Chen, assistant professor of electrical and computer engineering and one of the lead researchers on the project. “The eViper platform gives us a way to explore how electrical, mechanical, and power systems can be designed together to optimize energy use.”

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Over the past year, the team has published multiple research papers on their work. Their most recent study, presented at the 2023 IEEE International Conference on Intelligent Robots and Systems (IROS), was recognized as a finalist for the best paper award.

Alongside Professor Chen, the project was spearheaded by Princeton graduate students Hsin Cheng, Zhiwu Zheng, and Prakhar Kumar, with additional leadership from professors Naveen Verma, James Sturm, and Sigurd Wagner. The research received backing from several institutions, including the Princeton Materials Institute, Princeton Plasma Physics Laboratory, the Semiconductor Research Corporation, and the Andlinger Center for Energy and the Environment.