New aircraft designs are more flexible than ever before, making them susceptible to adverse aeroelastic phenomena such as a large dynamic response to atmospheric turbulence and even flutter. On the other hand, some studies suggest that wing flexibility can be leveraged to achieve optimal performance. This motivated the aeroelastic community to develop methods for sensing the deformed shape of flexible wings in-flight. The current research study proposes a novel method for shape sensing that is based on strain data, an aeroelastic model, and the use of the Kalman state estimator.
Several recent studies proposed different methods in which strain data, measured in optical fibers, can be used to estimate the deformed shape of a flexible wing. Fiber optic sensors typically provide accurate, high-resolution strain data, yielding accurate estimates of a wing’s deformed shape. However, the strain data could be imperfect (for example, due to saturation or temperature effects), corrupted, or missing. The current study proposes to use a Kalman state estimator that weighs strain data and simulation output of an aeroelastic model to estimate wing deformations. The method is demonstrated in a wind-tunnel test of a flexible wing model excited by prescribed control surface deflections. Fiber Bragg Grating sensors embedded in two optical fibers over the wing’s span measure strains, which are used to estimate the wing deformations. The latter are compared to wing deformations measured by a motion recovery camera system. Results show the advantages of the proposed method when the strain data or the aeroelastic model are imperfect. Additionally, the method provides smooth estimates of the modal velocities readily available for use by the vehicle’s control system.
