Tunable stiffness enables fast and efficient swimming in fish-like robots

Area of Science:

• Biomechanics
• Robotics
• Animal locomotion

Background:

• Fish exhibit remarkable swimming efficiency across various speeds.
• Achieving comparable performance in robotic fish remains a challenge, despite advancements in flexibility.

Purpose of the Study:

• To investigate how fish modulate tail stiffness using muscles to enhance swimming efficiency.
• To develop a model explaining the relationship between stiffness tuning and swimming performance.

Main Methods:

• Derivation of a mathematical model to analyze stiffness modulation effects.
• Analysis of how muscle tension scaling with swimming speed impacts efficiency.

Main Results:

• Muscle tension should scale with swimming speed squared for maximal efficiency.
• Tuning tail stiffness can double swimming efficiency at high frequencies and speeds.
• Energy savings increase with frequency, particularly beneficial for high-frequency robotic systems.

Conclusions:

• Tunable flexibility is crucial for fish swimming efficiency.
• The derived model provides a strategy for optimizing fish-like robots.
• Further research can leverage these findings for advanced bio-inspired robotics.