Aeroelastic Shape Control Using Fiber-Optic-Measured Strain Data and Multiple Control Surfaces

Abstract

The paper presents an experimental study of aeroelastic shape sensing and control based on strain data measured in fiber-optic sensors (FOSs). Past studies demonstrated how FOS strain data could be used to reconstruct the static and dynamic deformed shapes of a flexible wing. The current study further develops these capabilities and demonstrates wing shape control. Specifically, FOS-measured strain data are used in an optimization scheme, with a target of keeping the wing’s elastic deformations small, below a user-defined threshold, while maintaining a constant lift value (as required for trimmed flight) and with minimal usage of the control surfaces. The method is demonstrated computationally and experimentally on a wing model with four control surfaces. The wing was designed for this study, fabricated using additive manufacturing, and wind-tunnel tested. The trim optimization is performed both computationally and experimentally, following the same procedures but using strain and strain-modes data from finite element analysis and experiments. The wind-tunnel study demonstrated how a flexible wing’s shape could be controlled based on experimental strain data only, without resorting to a computational model. In both the computational and experimental parts of the study, considerable control-surface deformations were required. This primarily indicates that large control surfaces are not the optimal means for wing shape control. However, the same strain-based technique can be used with other effectors, such as distributed control surfaces, strain actuators, etcetera. The study opens a path to using FOSs to optimize winged unmanned-aerial-vehicle performance, and thus design lighter and more efficient platforms.