Robust Gust Load Alleviation at Different Flight Points and Mass configurations

Abstract

This work studies the gust load alleviation of a flexible aircraft equipped with a lidar sensor that measures the wind velocity ahead of the aircraft. The focus is put on the aeroelastic dynamics uncertainties due to the evolution of the velocity and the altitude during a flight, and to the variations of the aircraft mass configuration. A robust control approach is adopted in order to minimize the aircraft loads due to the wind in presence of such uncertainties with low-order controllers that satisfy the constraints imposed by the system's limitations and the implementability considerations. This is achieved through structured mixed H 2 /H ∞ synthesis with multiple models. The load alleviation capability of controllers of various orders, using a variable number of control surfaces, is assessed through the computation of the maximum loads obtained in various conditions of velocity, altitude and mass configurations.

Reduced-Order Identification of Aeroelastic Systems with Constrained and Imposed Poles

“…Gust Load Alleviation (GLA) [18,19] and active flutter suppression [20] are typical active research topics that are often based on linear models. If a trim equilibrium of the aircraft has been computed using nonlinear techniques, one can make the hypothesis of small displacements and deflections around this point such as done in [21,22], allowing to define linear structural dynamics of the incremental displacements.…”

Gust Load Alleviation Control of Aircraft with Varying Mass Distribution

“…[14] proposes a linear quadratic Gaussian regulator (LQG) to reduce the structural displacement. Using measurements of a light detection and ranging (LIDAR) sensor, which detects turbulence ahead of aircraft and therefore enables a faster reaction time to approaching gusts, is considered in several publications [15][16][17][18][19]. Feedforward control can be applied with LIDAR.…”

“…[15] additionally uses an adaptive control method in order to adapt to changes in the structural dynamics of aircraft. Quite popular is the application of H ∞ methods [6,9,17,19,20]. These aim at reducing the H ∞ norm of transfer functions within a certain frequency range [21].…”