Heliogyro Control

Abstract

Heliogyros with blade length-to-width aspect ratios of 1000 can achieve ambitious science mission goals, but such designs have not been analyzed with rigor. Archived heliogyro analyses indicate that aspect ratios of 1000 are feasible, but the calculations supporting this claim are based on the simplifying assumptions of decoupled twist, vertical deflection, and in-plane deflection of the blades. In making such simplifications, the equations become more tractable, but crucial behavioral characteristics are possibly lost. Without a more rigorous analytical investigation, the reliability and robustness of the heliogyro remains in doubt. However, with verified control models and an appropriate operations strategy, performance of aggressive heliogyro designs can be presumed. This thesis asserts that heliogyro blades with aspect ratios of 1000:1 can sufficiently operate in space. The crux of this investigation is a high-fidelity model that accurately represents a heliogyro blade. Pitch controls command the thrust vector of the large sail structure. Although the validation model mimics a real solar sail, the controller is driven toward the most simplified configuration. The results of this research validate that a model-based controller that neglects blade twist, coning, and wrinkling can sufficiently control the thrust vector of a suitably designed heliogyro.