ABSTRACT

This Faculty Early Career Development Program (CAREER) project will benefit the national interests from a scientific, economic, and security perspective by supporting fundamental research on bioinspired underwater robots equipped with actively morphing fins. The research work is inspired by marine creatures that continuously change their fins' shape and stiffness to achieve optimal energy advantage for different swimming regimes. This project will study the fundamental role of active fin stiffness and shape control for the purpose of enhanced underwater propulsion. Understanding this novel swimming paradigm will allow for robotic vehicles with highly efficient operation, enabling missions with extended duration and autonomy. As a result, the new knowledge will enable the development of next generation underwater robots for scientific exploration and ecological conservation of water bodies, underwater resource prospecting and mapping, and surveillance or stealth operations for defense purposes. Through an integrated research and education plan, this project will positively impact graduate and undergraduate students and will support K-12 STEM education in the state of Nevada and beyond, with emphasis to broadening participation of underrepresented students in engineering.

The research objective of this CAREER project is to establish the bioinspired framework of unsteady fluid-structure-control interactions which will address fundamental scientific questions in dynamical systems and enable an engineering paradigm shift in soft robotic underwater propulsion. This research will contribute new understanding of the complex interplay of morphing active flexible structures and the surrounding fluid environment by synergistically leveraging structural and fluid nonlinearities via self-sensing and feedback control. Models for self-sensing and control via smart materials embedded in artificial fins will be formulated and implemented. The system coupled dynamics will be studied theoretically and experimentally characterized via image-based motion analysis and flow diagnostics. Modeling, simulations, and experiments will be translated into robotic platforms to study bioinspired locomotion and test hypotheses on the effectiveness of active morphing. This project will advance the theory of nonlinear systems with time-periodic coefficients, by investigating control-induced instabilities and complex structural resonances mediated by nonlinear hydrodynamic actions. It will elucidate the potential of harnessing vortex shedding for flow control and its relation to modulation of hydrodynamic forces and power dissipation. Furthermore, this project will advance the current state-of-the-art in underwater robotic propulsion, by exploiting the transformative concept of active stiffness and shape morphing.

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.

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