Fish Muscles Reveal Hidden Senses for Smarter Underwater Robots
A researcher at Peking University's Intelligent Biomimetic Design Lab holds a live fish gently in a water tank while a 16-channel electrode array records real-time muscle electrical signals from its flank, capturing t...đˇ AI illustration
- â Bio-signal framework decodes muscle electrical activity
- â Posture and flow inferred without external sensors
- â Principles transferable to robotic systems
At the Intelligent Biomimetic Design Lab at Peking University, researchers have uncovered a dual function in fish muscles that goes beyond propulsion. Led by Professor Xie Guangming of the School of Advanced Manufacturing and Robotics, the team used a 16-channel device to record muscle electrical signals in real time. These signals were then processed to reconstruct the fishâs body posture and estimate local flow conditionsâessentially revealing an internal sensing system that operates without external sensors. The work, carried out by twin researchers Waqar Hussain Afridi and Rahdar Hussain Afridi, was published across three studies, including in Advanced Intelligent Systems.
The core innovation lies in treating muscle activity not just as a motor output but as a sensory input stream. In biological terms, fish are constantly adjusting to water movement, but it appears they also use muscular feedback to âfeelâ their orientation and the forces acting on them. This integrated approach reduces the need for separate inertial or pressure sensorsâa significant advantage for miniaturization and system resilience. As noted in the TechXplore Robotics report, the framework effectively turns the body into both actuator and sensor.
From biological signals to robotic control: the engineering bridge
An autonomous underwater vehicle (AUV) hovering in turbulent flow while relying on bulky external sensors, contrasting with the fish's internal sensing system revealed in the study.đˇ AI illustration
The source material also shows that for robotics, this biological principle opens a path to more adaptive underwater machines. Current autonomous underwater vehicles (AUVs) rely on a suite of external sensors to navigate complex flows, which adds cost, weight, and points of failure. A muscle-inspired control system could allow robots to sense disturbances and adjust posture using actuator feedback alone. This is especially valuable for tasks like pipeline inspection, coral reef monitoring, or military reconnaissance, where operating close to structures or in turbulent water is common.
However, moving from fish to robot involves scaling challenges. Fish muscles are dense, parallel-fibered, and coupled with a flexible skeletonâa hard combination to replicate mechanically. The research team is now working on translating the signal-processing algorithms into robotic controllers. Early prototypes will likely use soft actuators and strain sensors to mimic the biological coupling. The real test will be performance outside the lab: can the system handle sandstorms, strong currents, or prolonged operation without recalibration?