Aeroelastic and Trajectory Control of High Altitude Long Endurance Aircraft

We investigate the aeroelastic and trajectory control of an high altitude long endurance aircraft model in the presence of gust and turbulence disturbances. The model is derived from geometrically nonlinear beam theory using intrinsic degrees of freedom and linear unsteady aerodynamics, which results in a coupled structural dynamics, aerodynamics, and flight dynamics description. The control design employs a two-loop PI/linear active disturbance rejection control (LADRC) and H_∞ control scheme in both the longitudinal and lateral channels, based on a reduced-order linearized model. In each channel, the outer loop (position control) employs a PI/LADRC technique to track the desired flight routes and generate attitude command to the inner loop, while the inner loop (attitude control) uses H_∞ control to track the attitude command generated from the outer loop and computes the control inputs to the corresponding control surfaces. A particle swarm optimization algorithm is employed for parameter optimization of the weighting matrices in the H_∞ control design. The simulation tests conducted on the full-order nonlinear model show that the aeroelastic and trajectory control system achieves good performance with respect to robustness, trajectory tracking, and disturbance rejection.