Closed-loop speed control for a biohybrid neural interface using frequency-modulated lateral-line stimulation

Area of Science:

• Biohybrid Systems
• Neuroengineering
• Robotics

Background:

• Aquatic biohybrid systems offer potential for energy-efficient locomotion.
• Controlling biohybrid systems in real-time remains a challenge.
• Lateral-line neuromodulation is a promising method for controlling fish behavior.

Purpose of the Study:

• To achieve robust and energy-efficient target-speed regulation in free-swimming eels.
• To integrate closed-loop feedback with frequency-modulated lateral-line neuromodulation.
• To develop an adaptive biohybrid robotic system.

Main Methods:

• A closed-loop eel-computer biohybrid system was created using Monopterus albus.
• A microelectronic backpack noninvasively delivered electrical stimulation to lateral-line nerves.
• A proportional-derivative (PD) feedback controller adjusted stimulation frequency based on real-time velocity.

Main Results:

• Posterior lateral-line nerve (PLLN) stimulation induced forward swimming (9.0-17.8 cm/s) and anterior lateral-line nerve (ALLN) stimulation induced backward swimming (6.9-9.5 cm/s).
• Closed-loop control reduced velocity deviations by 63.7% (forward) and 50.6% (backward) compared to fixed-frequency stimulation.
• Stimulation power was energy-efficient, ranging from 0.87 to 1.54 mW/g.

Conclusions:

• Bidirectional closed-loop speed regulation in freely swimming eels was demonstrated.
• A compact, noninvasive framework for adaptive, energy-efficient aquatic biohybrid robots was established.
• Lateral-line-driven neural interfaces provide a viable approach for biohybrid system control.