From Theory to Thrust: Revealing the Role of Actuation and Sensing in How Undulatory Swimmers Change Speed

Acceleration is essential for the locomotion of both living and robotic swimmers. Fish constantly change their speed to capture prey, avoid predators, and maneuver through complex habitats. Yet, we lack a framework to understand how undulatory swimmers change their swimming speed. A greater understanding of underwater acceleration would have important biological, ecological and engineering applications, including enabling the design of bio-inspired vehicles that better swim in the turbulent waters of coastal zones where critical environmental monitoring is necessary to understand the impacts of climate change. This research project aims to use both biology and engineering perspectives to uncover how undulatory swimmers change their swimming speed by coordinating their muscle actuation with their ability to sense their own motion and the surrounding flow. Research findings will be shared with the public through multimedia and K-9 outreach programs. The goal of this project is to understand the role of actuation and sensing in coordinating the acceleratory kinematics that allow undulatory swimmers to change swimming speed. This project will identify the fundamental acceleration mechanisms using an interdisciplinary approach that combines computational modeling of kinematics, hydrodynamic and kinematic testing of soft robotic swimmers, and biological testing of accelerating fishes. This research will focus on four specific aims: (i) establishing physics-based relationships that describe the role of actuation in acceleration, (ii) identifying the breakdown mechanisms of acceleration at the limits of swimming speed, (iii) identifying the role of sensory feedback activity in biological fishes during acceleration, and (iv) understanding how kinematic sensing and muscle actuation are coordinated to control acceleration. By integrating biology and engineering, this research will uncover the acceleration mechanisms of biological and robotic undulatory swimmers which will provide insights that extend to the sensorimotor control of bio-inspired vehicles. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.