These machines utilize integrating power sources within their structure to drastically reduce weight and enhance functionality
Taking a cue from nature’s evolutionary path from water to land, the Organic Robotics Lab and the Archer Group at Cornell Engineering have made a fascinating development in modular robotics.
Their new worm and jellyfish robots are built around the transformative concept of “embodied energy,” where integrating the power source into the robot’s structure reduces weight and cost, mirroring the evolutionary advancements from aquatic to terrestrial life.
The technology stems from a 2019 prototype inspired by a lionfish, utilizing a hydraulic fluid system, or “robot blood,” that powers devices by circulating energy. This system has been refined for higher battery capacity and power density, supporting the new robotic forms in more complex environments.
Professor Rob Shepherd explains that the jellyfish’s enhanced capacity allows it to operate longer than its aquatic predecessor, while the worm, their first terrestrial model, demonstrates greater freedom of movement without needing a rigid structure.
Innovative battery design propels Cornell’s jellyfish robot
Both bio-inspired robots’ core is the redox flow battery (RFB), a system where electrolytic fluids catalyze energy release through redox reactions. This “beating heart” powers the robots efficiently and sustainably.
The jellyfish robot, in particular, leverages an RFB enhanced by a tendon mechanism. This design allows the jellyfish to alter its shape and achieve movement, ascending when the bell expands and descending as it relaxes.
Professor Rob Shepherd highlights the leap in battery technology led by Lynden Archer’s team. Their robot features dual redox batteries using zinc iodide and zinc bromide. A key advancement is the integration of graphene, which prevents dendrite buildup, facilitating smoother and more reliable battery charging cycles.
Additionally, the strategic addition of bromine enhances ion transport in the zinc bromide battery, substantially boosting the robot’s power density and operational agility. These enhancements have extended the jellyfish robot’s active period to about 90 minutes, significantly increasing its efficacy and speed.
Modular design enhances mobility in Cornell’s worm robot
The worm robot showcases its unique, modular design, consisting of interconnected pods, each equipped with a motor and tendon actuator. This configuration allows the robot to alter its shape dynamically, enabling a broad range of movements.
Chong-Chan Kim, the study’s lead author, employed a novel dry-adhesion method during the manufacturing process, bonding Nafion separators directly to the robot’s frame. This technique efficiently separates anolytes and catholytes within the robot, facilitating smooth electron flow and energy distribution.
Professor Shepherd explained the dual functionality of the hydraulic fluid used in the robot, serving both as a battery and a force provider. “This dual role not only reduces the robot’s overall weight but enhances its energy efficiency, allowing for extended travel distances,” Shepherd noted.
The worm robot’s design enables it to navigate challenging terrains, from inching along flat surfaces to scaling vertical pipes using a two-anchor crawling method similar to a caterpillar’s movement.
Although not built for speed, taking about 35 hours to cover 344 feet (105 meters), the worm robot is faster than other hydraulically powered counterparts. It is ideally suited for exploration in confined spaces like pipelines, potentially aiding in maintenance and repairs.
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Both robots represent significant progress toward robust, energy-efficient robotic designs capable of performing complex tasks in different environments. Shepherd envisions incorporating high-capacity lithium-polymer batteries in embodied-energy robots with skeletal structures as this technology evolves, making them more versatile.
