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The main direction of aircraft design today and in the future is to achieve more lightweight and higher aspect ratio airframes with the aim to improve performance and to reduce operating costs and harmful emissions. This promotes the development of flexible aircraft structures with enhanced aeroelastic behaviour. Increased aeroservoelastic (ASE) effects such as flutter can be addressed by active control technologies. Control design for flutter suppression heavily depends on the control surface sizing. Control surface sizing is traditionally done in an iterative process, in which the sizing is determined considering solely engineering rules and the control laws are designed afterwards. However, in the case of flexible vehicles, flexible dynamics and rigid body control surface sizing may become coupled. This coupling can make the iterative process lengthy and challenging. As a solution, a parametric control surface design approach can be applied, which includes limitations of control laws in the design process. For this a set of parametric models is derived in the early stage of the aircraft design. Therefore, the control surfaces can be optimized in a single step with the control design. The purpose of this paper is to describe as well as assess the developed control surface parameterized ASE models of the mini Multi Utility Technology Testbed (MUTT) flexible aircraft, designed at the University of Minnesota. The ASE model is constructed by integrating aerodynamics, structural dynamics and rigid body dynamics. In order to be utilized for control design, control oriented, low order linear parameter-varying (LPV) models are developed using the bottom-up modeling approach. Both grid- and polytopic parametric LPV models are obtained and assessed.

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Hybrid-electric, unconventional aircraft solutions can possibly be the solutions for the ambitious emission reduction targets set by regulators, based on society's demands. One such disruptive solution is a morphing wing cargo UAV, with distributed propulsion. This paper investigates the aerodynamics, flight dynamics and control of a scaled down technology demonstrator UAV, built to validate the feasibility of the morphing wing concept. Several types of analyses are run to gain knowledge on the performance, stability and control properties of the aircraft. The flight mechanical effects of the distributed propulsion system are taken into account based on the integral momentum theorem. The increased flow speed behind propellers increases the local lift forces. Therefore, the distributed propulsion can be used to control the roll, pitch and yaw motion of the morphing wing aircraft. The nonlinear 6 degrees of freedom, distributed propulsion aircraft model is constructed utilizing the stability and control derivatives obtained from the aerodynamic analysis. Grid and Tensor Product (TP) type linear parameter-varying (LPV) models of the morphing wing aircraft are generated via Jacobian linearization and TP model transformation. The LPV models capture the parameter varying dynamics arising from the airspeed, morphing wing and payload weight variations. Gain scheduled lateral and longitudinal baseline controllers are synthesized using the grid-based LPV model of the aircraft.

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