Spatial Control of Spanwise Lift Distribution for Gust Alleviation

2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. This work presents a novel approach to gust alleviation, based on the application of shape control techniques to the lift distribution profile along a wing featuring trailing edge flaps. The spanwise lift distribution is modeled using the Unsteady Vortex Lattice Method (UVLM), yielding a linear, time-invariant, high-order state-space model. The Eigensystem Realization Algorithm (ERA) is applied for model-order reduction and modal identification, providing aerodynamic mode shapes and associated eigenvalues. By expanding the system output (lift distribution) as a truncated superposition of aerodynamic mode shapes, a low-order MIMO modal representation is obtained, suitable for controller synthesis. In this work, this methodology is used to synthesize regulators, to drive lift disturbance caused by exogenous inputs (gusts) to zero, and also trackers, to dynamically follow any desired reference lift profile. The loads induced by a discrete gust (shear force and bending moment at the wing root) were reduced by 50%, as compared to the open-loop case. A special observer structure decouples the gust input from the state estimation process, thus providing not only estimates for all shape coefficients, but also for the gust amplitude along time.

Spatial Control of Spanwise Lift Distribution for Gust Alleviation Conference Paper