Aeroelasticity of Bird-Inspired UAVs

Abstract

Unmanned aerial vehicles (UAVs) have been developed and used in different applications that involve technical operations in engineering and entertainment. Among the different types, bio-inspired UAVs stand out, which involve wing movement, typically called flapping wing systems. The main types of these vehicles are inspired by insects and birds, respectively called insect-like and bird-like UAVs (Unmanned Aerial Vehicles). The works in this area, in general, approach the rigid body dynamics of the vehicles, neglecting aerodynamic effects, as usually done for conventional UAVs with rotation wings or, on the other hand, consider the modeling of aerodynamic forces, with a predominantly quasi-stationary approach, being applications with non-stationary aerodynamics limited. In this context, this project comprises the study of small UAVs inspired by birds, such as the ornicopter, through the aeroelastic modeling of the SUAV vehicle (Small Unmanned Aerial Vehicle), which includes the structural model, the aerodynamic model and the mesh coupling . Also, the scope involves testing with prototypes. The research objectives are: to develop a structural model of the SUAV vehicle using the Finite Element method and to couple the structural mesh to a mesh of panels obtained for non-stationary aerodynamics of flapping wing systems, obtain the aeroelastic model and perform divergence analysis, among others; to develop a control strategy for SUAV mainly based on LMIs (Linear Matrix Inequalities) in order to ensure the flight in a previously defined trajectory; and perform flight tests to prove the developed modeling and control methodologies. The Finite Element Method (FEM) will be considered to develop the structural model of the SUAV. The aerodynamic forces will be obtained using the panels method for non-stationary potential aerodynamics, already developed for flapping wing systems. The Virtual-Works-based method will be employed to connect the structural and aerodynamic meshes. As a control strategy, LMI controllers will be considered, especially based on Fuzzy Takagi-Sugeno approaches and on Affine Parameter Models, duly converted to convex models, mainly aiming to enable the use of modern controllers, with relaxation strategies in relation to quadratic stability. The central idea is to compute control forces, based on states and/or outputs, to obtain the flight on a previously defined trajectory. Flight tests will be carried out indoor and outdoor to verify the performance of the designed controllers.