Test operation of the Altaeros BAT in 2013
3D printed model of the 2013 Altaeros BAT undergoing flight characterization in the UNC-Charlotte water channel
Mitchell Cobb Graduate Student
University of North Carolina at Charlotte Department of Mechanical Engineering
and Engineering Science Control and Optimization for Renewables
and Energy Efficiency (CORE) Lab
9201 University City Blvd. Duke Centennial Hall 380 Charlotte, NC 28223-0001
U.S.A.
mcobb12@uncc.edu coefs.uncc.edu/cvermill
Evolution of a Lab-Scale Platform for Dynamically-Scalable Characterization of
Airborne Wind Energy System Flight Dynamics and Control
Chris Vermillion, Mitchell Cobb, Nihar Deodhar, Joe Deese University of North Carolina at Charlotte
Over the past four years, researchers at the University of North Carolina at Charlotte, University of Michigan, and Altaeros Energies have developed a lab-scale platform for characterizing the flight dynamics and control of airborne wind energy (AWE) systems. This work started in 2013 with a lab-scale, water channel-based system for char-acterizing passive flight dynamics. The system was en-hanced in 2014 to support closed-loop control and was fur-ther augmented in 2015-2016 with additional image pro-cessing and control features that allowed for the demon-stration of crosswind flight. This presentation will review the evolution of this lab-scale platform, discuss the dy-namic scaling results that relate lab- and full-scale flight behavior, and review recent successful efforts to emulate crosswind flight at lab-scale.
The lab-scale system described herein began as a sim-ple platform for qualitatively assessing the performance of the Altaeros Buoyant Airborne Turbine (BAT), as de-scribed in [1] and [2]. In 2015, this system was augmented to incorporate closed-loop control, still under stationary operation [3]. Recently, we have shown in [4], using di-mensional analysis (via the Buckingham Pi Theorem) that these lab-scale results correlate with full-scale flight re-sults, with the only difference being uniformly acceler-ated time constants at lab-scale. Finally, we have recently extended our lab-scale framework and dynamic similar-ity analysis to accommodate crosswind flight, as initially disclosed in [5]. In fact, the dynamic similarity results from [4] have been extended to crosswind flight as well.
Furthermore, these dynamic similarity results have been corroborated through validation experiments at multiple model scales. This presentation will review (i) the state of the UNC-Charlotte experimental platform, (ii) the dy-namic similarity analysis, and (iii) the validation experi-ments used to corroborate the results of this analysis.
References:
[1] Vermillion, C., Glass, B., Greenwood, S. łEvaluation of a Water Channel-Based Platform for Characterizing Aerostat Flight Dynam-ics: A Case Study on a Lighter-Than-Air Wind Energy System," in AIAA Lighter-Than-Air Systems Conference, Atlanta, GA, 2014. [2] Vermillion, C., Glass, B., Szalai, B., łDevelopment and Full-Scale Experimental Validation of a Rapid Prototyping Environment for Plant and Control Design of Airborne Wind Energy Systems," in ASME Dynamic Systems and Control Conference, San Antonio, TX, 2014.
[3] Deese, J., Muyimbwa, T., Deodhar, N., Vermillion, C., Tkacik, P., łLab-Scale Experimental Characterization of a Lighter-Than-Air Wind Energy System - Closing the Loop," in AIAA Lighter-Than-Air Systems Technology Conference, Dallas, TX, 2015.
[4] Deodhar, N., Bafandeh, A., Deese, J., Smith, B., Muyimbwa, T., Vermillion, C., Tkacik, P., łLaboratory-Scale Flight Characterization of a Multitethered Aerostat for Wind Energy Generation," AIAA Jour-nal, Vol. 55, Issue 6, pp. 1823-1832, 2017.
[5] Cobb, M., Vermillion, C., Fathy, H., łLab-Scale Experimental Crosswind Flight Control System Prototyping for an Airborne Wind Energy System," in ASME Dynamic Systems and Control Confer-ence, Minneapolis, MN, 2016.
