Grid-based LPV Modeling of Aeroelastic Aircraft with Parametrized Control Surface Design

The fuel efficiency of future aircraft can be improved by reducing the weight and structure and by increasing the wingspan. This makes the aircraft structure more flexible and results in increased aeroservoelastic (ASE) effects. The use of active control systems to suppress ASE effects is an important aspect for future flight control systems. Control surface sizing is traditionally done in an iterative process. In such approach the size is determined based on engineering rules for which then the control laws are engineered. This approach, in addition to being time consuming, might not be applicable for future aircraft in which the flexible dynamics and rigid body control surface sizing can become coupled. Instead, a parametric control surface design approach can be applied, which to engineering rules takes limitations of control laws into consideration. Therefore, the control surfaces can be optimized in a single step with the control design. The aim of this paper is to develop a control oriented, control surface parametrized ASE model of the mini MUTT flexible aircraft, designed at the University of Minnesota. The ASE model is based on the integration of aerodynamics, structural dynamics and flight dynamics. A grid based linear parameter-varying (LPV) model is obtained from the nonlinear ASE model, which can serve as a basis for simultaneous control surface sizing and baseline/flutter suppression control synthesis optimization. The resulting parametric control surface LPV models are assessed with the help of numerical simulations including a gain scheduled baseline controller.