Longitudinal Short-Period Aircraft Motion Control Under Loadcase Variation

In this paper, an LPV longitudinal flight controller design is presented, which takes variations of mass and mass distribution into account without the need for additional measurements or estimation of the current loadcase (a certain combination of mass, center of gravity and inertia tensor). This means the loadcase variation is included in the LPV model, but the obtained controller depends on the measurable variations of altitude and airspeed only. Therefore, a technique based on LPV systems with partly-measurable parameters is used. This approach is applied to the control of the short-period dynamic on a model of a small regional aircraft. The obtained controller is evaluated on a more detailed linear model, which takes parts of the real control system into account, as well as within a 6DOF high-fidelity nonlinear simulation environment, which is used to analyze flight controllers before real-life flight tests.