Researchers explore fish movement to enhance underwater robots

By taking a deep dive into the complex interaction between structure and fluid dynamics, mechanical engineering professors hope to advance bio-inspired technology


By Erin Cassidy Hendrick

UNIVERSITY PARK, Pa. — To understand the sensing, control and physics of fish-swimming with the goal of mimicking their performance in advanced robotics, researchers in the Penn State Department of Mechanical Engineering, in collaboration with the University of Houston and the University of Virginia, have recently been awarded a $1.2 million grant from the National Science Foundation (NSF).

Penn State’s Bo Cheng, assistant professor of mechanical engineering, and Asok Ray, distinguished professor of mechanical engineering, will receive $550,000 of the grant as the principal investigators to develop a bio-inspired robot fish platform and the corresponding learning algorithm to control and optimize its movements in underwater environments. 

“We essentially want to study locomotion in fluids, by learning how fish swim and then use that fundamental knowledge to optimize robotic swimming,” Cheng said. “The high-level objective is to understand how structure can move efficiently in water.”

At the University of Houston, researchers will develop a stretchable skin with sensors to gather flow and pressure data while the robot is moving within the water. Meanwhile, at the University of Virginia, researchers will study the physics of the fluid and its corresponding impact on the structure of the robot.

This data will inform the work at Penn State in several ways: The corresponding robot fish platform will use the sensors to detect nearby objects to adjust its path accordingly and be able to optimize the control strategy of the robot’s movement in fluid.

“Through this collaboration, the key problem we hope to understand is the fundamental nature of fluid structure interaction in the context of underwater locomotion, investigated as a biologically-inspired, cyber-physical system,” Cheng said.

Ray explained similar problems are studied extensively in the aerospace industry, where aircrafts contend with the fluid dynamics of the atmosphere and wind patterns.

“However, there is less work exploring the impacts in underwater technology,” he said. “There will be significant technical differences and challenges, but the knowledge can be applied to many other disciplines.”

Cheng’s work largely examines flying animals to better understand and quantify their biologically masterful movements. By unlocking the science behind these fundamental challenges, more powerful and efficient robotics can be developed.

The knowledge gleaned from this project will also serve to elevate Ray’s research.

“This project is of great interest to my work in robotics, since the fluid environment is much more complicated than where I usually conduct my work,” he said. “It is fascinating to mix the physics of fluids with the ability of sensors, robots and controls.”

The project will be funded for three years by the NSF Cyber-Physical Systems (CPS) program, which supports research into engineered systems that are built and optimized with the seamless integration of computational and physical components. 

“The work is truly in the spirit of CPS, it merges the physical challenges of moving within water and how the different disciplines inside the robot are sensing, controlling and learning,” Ray said. “It is important to unify this knowledge.”

By taking this deep dive into the physics of fish locomotion, the researchers hope to make discoveries that influence a new understanding of robotics development. For instance, it could enhance search-and-rescue missions in the ocean or in confined underwater environments or help develop nanoscale technology that could deliver medical treatments by swimming in blood vessels.

Looking ahead, the researchers appear to be wading into a sea of potentially unlimited applications.


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Megan Lakatos

“We essentially want to study locomotion in fluids, by learning how fish swim and then use that fundamental knowledge to optimize robotic swimming. The high-level objective is to understand how an object can move most efficiently in water.”
—Bo Cheng, assistant professor of mechanical engineering



With more than 60 faculty members, 330 graduate students, and 800 undergraduate students, the Penn State Department of Mechanical Engineering embraces a culture that welcomes individuals with a diversity of backgrounds and expertise. Our faculty and students are innovating today what will impact tomorrow’s solutions to meeting our energy needs, homeland security, biomedical devices, and transportation systems. We offer B.S. degrees in mechanical engineering as well as resident (M.S., Ph.D.) and online (M.S.) graduate degrees in mechanical engineering. See how we’re inspiring change and impacting tomorrow at

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