Aquatic life inspires next wave of prosthetics

Muscle movements in fish shift the current of research and development of assistive technologies for those with disabilities

Students building robotic fish with professor

RIT mechanical engineering students Tzu-Ting Hsu and Maxwell Reitz and their Professor Kathleen Lamkin-Kennard are inspired by nature to build robotic technologies that can be incorporated into wearable prosthetic devices.

It started with the keen observation of the short, powerful, yet simple, muscle movements of the common river trout.

A team of RIT engineering students began to experiment with replicating those movements to create a fully submersible robot fish using elastomeric material, a super strong, stretchy fiber that carries an electrical charge. Using that charge, the material contracts, similar to the way human muscles do after receiving an electrical impulse from the brain.

RIT researchers say the technology could lead to a new wave of prosthetics that can help those with disabilities to regain fine motor skills.

Making a robotic fish means researching and studying how real fish move. It’s an assignment Professor Kathleen Lamkin-Kennard gives to her engineering students, the first step in designing a robotic creature that moves as sinuously as a real fish.

“I was looking for a fun senior design project. Students like to build things, and the soft, stretchy muscle actuators (artificial muscles) are lightweight and present an interesting design challenge,” said Lamkin-Kennard, a professor of mechanical engineering at RIT’s Kate Gleason College of Engineering.

"We made these robotic creatures. But for me, it is really the end goal—how can we adapt this?"


While whimsical, it is serious science where flexible muscles designed today could be part of better functioning assistive technologies for people tomorrow. Lamkin-Kennard’s students are learning to understand motion and to replicate it through technology that might mean mobility for people with disabilities.

Lamkin-Kennard’s work builds on her experience in industry, where she helped to develop a high-fidelity, robotic patient simulator device. She used that experience to create unconventional multidisciplinary senior design projects, starting with a robotic hand in response to an increased interest in prosthetics and wearable technologies. That early work proved soft muscle actuators could be used for different types of motion. New projects evolved into robotic systems that walked, jumped, and swam.

“There is a big push in the robotics field for taking inspiration from nature. There are some very efficient designs in nature and in the bodies of animals that are just so spectacular. How can we use that?” said Lamkin-Kennard, whose menagerie of robotic animals now includes an ant, otter, trout-like fish, and a multi-leg crab—all built using flexible actuators and sensor technology.

Overhead photo of robotic fish

“We made these robotic creatures. But for me, it is really the end goal—how can we adapt this?” said Lamkin-Kennard, who collaborates with peers in RIT’s assistive technology group, who work to expand techniques for exoskeletons and surgical robots using newer, evolving elastomeric materials.

What if more assistive devices could be built with this technology? “That’s what we are looking at long term,” she said.

For RIT, it’s this kind of research and creative thinking that fuels innovations that move the world forward. These robots are a direct result of the inquisitive nature of faculty and students, who are encouraged to explore the wonder and possibility of their own ideas. Students and faculty tinker and test, and reimagine when needed, to solve problems that impact the world around them.

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