Just as land animals evolved from aquatic creatures, soft robots are advancing too, thanks to new research from Cornell University focused on battery innovation and design.
A modular worm robot and a jellyfish illustrate the advantages of what’s known as “embodied energy” — a technique that integrates power sources within the body of the robot, helping to decrease weight and cut costs.
The worm and jellyfish are evolved versions of an earlier soft robot inspired by a lionfish, which was introduced in 2019. This original design could store energy and function using a circulating hydraulic fluid, likened to “robot blood.” These new designs have similar sustenance systems but come with enhancements for better battery efficiency and energy output.
“The jellyfish boasts a higher weight-to-capacity ratio, allowing it to travel much longer than the fishes,” stated Rob Shepherd, a professor of mechanical and aerospace engineering who oversaw both projects. “The worm represents our first attempt to create a version that operates above water. When submerged, buoyancy aids the robot, eliminating the necessity for a rigid skeleton.”
An important aspect of the worm robot is its segmented design. The worm’s structure consists of several connected pods, each housing a motor and tendon actuator that enable the worm to change shape and motion, along with stacks of anolyte pouches surrounded by catholyte.
“Many robots rely on hydraulic power, but we are the first to utilize hydraulic fluid as a battery. This fusion lowers the overall weight because it serves dual purposes: supplying energy to the system and generating the force needed for movement,” Shepherd explained. “As a result, we can have a worm that is nearly entirely energy-centric, allowing it to traverse significant distances.”
The researchers experimented with two movement styles. The worm can crawl along the ground by contracting each pod sequentially to move forward, or it can navigate vertically through a pipe in a caterpillar-like motion known as two-anchor crawling.
Although the robot isn’t particularly fast—it would take about 35 hours to cover 105 meters on a single charge—it does outperform other hydraulic-powered worm bots. This worm design is particularly promising for investigating long and narrow spaces like pipelines, as well as for potential repair tasks.
Similarly, the jellyfish robot is envisioned as a cost-effective tool for exploring ocean depths, as it can drift with currents, rise to the surface for communication, and then dive back down.
This research was funded by the Office of Naval Research and the Department of Energy’s Basic Energy Sciences Program.
