Distributed flow sensing for closed-loop speed control of a flexible fish robot.

Area of Science:

• Robotics
• Fluid Dynamics
• Biomimetics

Background:

• Fish flexibility is crucial for maneuverability in predator avoidance and turbulent flows.
• Robotic systems can benefit from biomimetic designs for enhanced aquatic locomotion.

Purpose of the Study:

• To develop a flexible fish robot with integrated pressure sensors for flow sensing.
• To implement a closed-loop speed control strategy for the robot based on estimated flow conditions.

Main Methods:

• A flexible fish robot body was constructed from soft, hyperelastic material with a Joukowski-foil shape.
• Quasi-steady potential-flow and discrete-time vortex-shedding models were used for flow estimation and simulation.
• A recursive Bayesian filter assimilated pressure measurements to estimate flow parameters.
• A closed-loop speed-control strategy combined feedforward and proportional-integral feedback controllers.

Main Results:

• The study demonstrated the effectiveness of the distributed pressure sensing system for flow estimation.
• The closed-loop control strategy successfully regulated the robot's speed by adjusting flapping amplitude.
• Both simulation and experimental results validated the proposed estimation and control approach.

Conclusions:

• A systematic approach for distributed flow sensing and closed-loop speed control in flexible robots was established.
• The flexible fish robot design enables effective maneuverability and adaptive swimming in fluid environments.
• This research advances biomimetic robotics and intelligent control systems for underwater applications.