Cornell's Soft Robots: Jellyfish & Worm Powered by Hydraulic Fluid

Bio-Inspired Robots Powered by Novel Hydraulic Fluid Battery

A groundbreaking development in robotics was presented by researchers at Cornell University on Monday. They demonstrated two robots – a worm and a jellyfish – that operate using a battery powered by hydraulic fluid.

This innovative battery, a redox flow battery (RFB), also draws inspiration from biological systems. It functions by releasing electrolytic fluids, initiating a chemical reaction that generates energy.

Design and Functionality of the Robots

The modular worm and jellyfish robots were created within the Cornell Engineering laboratories. These systems benefit from embodied energy, a design approach that integrates the power source directly into the robot’s structure.

This integration serves to minimize both the weight and the overall cost of the robotic devices.

The Technology Behind the Hydraulic Battery

Professor Rob Shepherd, from the Departments of Mechanical and Aerospace Engineering, explained the core principle: “Many robots utilize hydraulic power, but we are the first to employ hydraulic fluid as the battery itself.”

This dual functionality – providing both energy and the force for movement – significantly reduces the robot’s weight.

Enhanced Performance and Runtime

The new battery technology has demonstrably improved the robots’ capabilities. Specifically, the jellyfish robot’s operational runtime has been extended to an impressive hour and a half.

The jellyfish’s design builds upon previous work by the school, including a biologically-inspired robot modeled after a lionfish, which was unveiled in 2019.

Researchers previously described the circulating liquid within that system as “robot blood,” leading to the playful notion of the battery functioning as a “robot heart.”

Jellyfish Robot Mechanics

The jellyfish robot utilizes a tendon that, when flexed into a bell shape, propels the robot upwards. Relaxation of this shape allows the robot to descend.

Video footage reveals remarkably natural jellyfish-like movements as the robot navigates through water.

Worm Robot Construction and Locomotion

The worm robot is constructed from interconnected, modular segments, reminiscent of designs seen in larger snake robots.

Each segment incorporates a motor and a tendon actuator, which expands and contracts to facilitate movement.

Challenges of Transitioning to Land

The research team highlighted the difficulties encountered when adapting the technology for terrestrial use.

A key challenge is that robots operating underwater do not require the structural support of a rigid skeleton.

Evolutionary Inspiration

“This mirrors the evolution of life on land,” Shepherd stated. “Starting with aquatic creatures, organisms transitioned to simpler forms supported by the ground.”

He further explained that the worm, while simple, possesses a greater range of motion than many other designs.