@article{abney_reed_naik_bryant_herbert_leonard_vadlamannati_mook_beknalkar_alvarez_et al._2022, title={Autonomous Closed-Loop Experimental Characterization and Dynamic Model Validation of a Scaled Underwater Kite}, volume={144}, ISSN={["1528-9028"]}, DOI={10.1115/1.4054141}, abstractNote={Abstract
               This paper presents the closed-loop experimental framework and dynamic model validation for a 1/12-scale underwater kite design. The pool-based tow testing framework described herein, which involves a fully actuated, closed-loop controlled kite and flexible tether, significantly expands upon the capabilities of any previously developed open-source framework for experimental underwater kite characterization. Specifically, the framework has allowed for the validation of three closed-loop flight control strategies, along with a critical comparison between dynamic model predictions and experimental results. In this paper, we provide a detailed presentation of the experimental tow system and kite setup, describe the control algorithms implemented and tested, and quantify the level of agreement between our multi-degree-of-freedom kite dynamic model and experimental data. We also present a sensitivity analysis that helps to identify the most influential parameters to kite performance and further explain the remaining mismatches between the model and data.}, number={7}, journal={JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME}, author={Abney, Andrew and Reed, James and Naik, Kartik and Bryant, Samuel and Herbert, Dillon and Leonard, Zak and Vadlamannati, Ashwin and Mook, Mariah and Beknalkar, Sumedh and Alvarez, Miguel and et al.}, year={2022}, month={Jul} }
 @article{beknalkar_naik_vermillion_mazzoleni_2022, title={Closed-Loop-Flight-Based Combined Geometric and Structural Wing Design Optimization Framework for a Marine Hydrokinetic Energy Kite}, ISBN={["978-1-6654-6809-1"]}, ISSN={["0197-7385"]}, DOI={10.1109/OCEANS47191.2022.9977369}, abstractNote={A marine hydrokinetic (MHK) kite offers an economical solution to the challenges of size and investment costs posed by the existing class of energy converters used to harvest tidal and ocean current energy. MHK kite systems are complicated devices that harvest ocean current energy by flying a tethered kite perpendicular to the motion of the current flow. They possess strong coupling between closed-loop flight control, geometric design, and structural design and hence it is important to consider all three facets simultaneously while designing a MHK kite system. Our previous work addressed this problem of simultaneous optimization of plant and controller through a control-aware optimization framework that fuses a geometric optimization tool, a structural optimization tool, and a closed-loop flight efficiency map. While our previous work analyzed the effect of key wing geometric parameters (wingspan and aspect ratio) on the performance of MHK kite systems, the present work represents the next crucial step in the study of ocean energy-harvesting kite systems and expands the design space to include several other wing geometric parameters - airfoil design, wing taper, wing twist, and dihedral angle. The effect of these decision variables on the power-to-mass ratio is estimated through an optimization framework based on a sequential approach. First, using sensitivity analysis, the framework determines which design variables in the design space affect the peak mechanical power generated while flying a cross-current path. In the next step, the combined geometric and structural optimization tool derives optimal values of variables in the reduced design space that results in a minimum structural mass. The constraints in the optimization problem include a lower limit on the peak power and limits on the number and dimensions of I-beam spars and the thickness of the wing shell. With a wing structure that can sustain peak lifting loads equal to less than a fixed value, the rest of the design variables are optimized to achieve maximum time-averaged power using medium-fidelity closed-loop-flight-based simulations. The final results of the optimization framework include an optimized wing geometry and wing structure with a maximized power-to-mass ratio for an MHK kite.}, journal={2022 OCEANS HAMPTON ROADS}, author={Beknalkar, Sumedh and Naik, Kartik and Vermillion, Chris and Mazzoleni, Andre}, year={2022} }
 @article{naik_beknalkar_reed_mazzoleni_fathy_vermillion_2023, title={Pareto Optimal and Dual-Objective Geometric and Structural Design of an Underwater Kite for Closed-Loop Flight Performance}, volume={145}, ISSN={["1528-9028"]}, DOI={10.1115/1.4055978}, abstractNote={Abstract
               This paper presents the formulation and results for a control-aware optimization of the combined geometric and structural design of an energy-harvesting underwater kite. Because kite-based energy-harvesting systems, both airborne and underwater, possess strong coupling between closed-loop flight control, geometric design, and structural design, consideration of all three facets of the design within a single codesign framework is highly desirable. However, while prior literature has addressed one or two attributes of the design at a time, this work constitutes the first comprehensive effort aimed at addressing all three. In particular, focusing on the goals of power maximization and mass minimization, we present a codesign formulation that fuses a geometric optimization tool, structural optimization tool, and closed-loop flight efficiency map. The resulting integrated codesign tool is used to address two mathematical optimization formulations that exhibit subtle differences: a Pareto optimal formulation and a dual-objective formulation that focuses on a weighted power-to-mass ratio as the techno-economic metric of merit. Based on the resulting geometric and structural designs, using a mediumfidelity closed-loop simulation tool, the proposed formulation is shown to achieve more than three times the powerto-mass ratio of a previously published, unoptimized benchmark design.}, number={1}, journal={JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME}, author={Naik, Kartik and Beknalkar, Sumedh and Reed, James and Mazzoleni, Andre and Fathy, Hosam and Vermillion, Chris}, year={2023}, month={Jan} }