Researchers at Cornell University on Monday showcased a pair of bio-inspired robotics running on a hydraulic fluid-powered battery. The redox flow battery (RFB) also mimics biological functions, as it releases electrolytic fluids, which dissolve to create energy through chemical reaction.
The first two robots on display are a modular worm and a jellyfish, designed by the Cornell Engineering labs. The batteries powering these systems utilize embodied energy, “an approach that incorporates power sources into the body of a machine, to reduce its weight and cost,” according to the school.
Mechanical and aerospace engineering Professor Rob Shepherd describes the underlying technology thusly: “There are a lot of robots that are powered hydraulically, and we’re the first to use hydraulic fluid as the battery, which reduces the overall weight of the robot, because the battery serves two purposes, providing the energy for the system and providing the force to get it to move.”
In addition to improving the speed and movements, the battery technology extended the robot jellyfish’s runtime to an hour and a half. The robot itself was built atop technology the school utilized in the development of a lionfish-inspired biological robot. When that system was unveiled in 2019, researchers referred to the circulating liquid as “robot blood,” which presumably makes the battery a robot heart.
The RFB powering the jellyfish features a tendon that propels the robot upward when flexed into a bell shape. When the shape is relaxed, the robot sinks down. Footage of the system in action showcases familiar jellyfish-like movements as it navigates through the water.
The worm, meanwhile, is constructed from modular segments, similar to those seen on larger snake robots. Each segment contains a motor and a tendon actuator, which expands and contracts to create locomotion.
The team notes that the transition from underwater to land presented its own challenges. Chief among them is the fact that submerged robots don’t require a rigid skeletal structure.
“This is how life on land evolved,” Shepherd says. “You start with the fish, then you get a simple organism and it’s supported by the ground. The worm is a simple organism, but it has more degrees of freedom.”
