Study of a Flexible UAV Proprotor

This paper is concerned with the evaluation of design techniques, both for the propulsive performance and for the structural behavior of a composite flexible proprotor. A numerical model was developed using a combination of aerodynamic model based on Blade Element Momentum Theory (BEMT), and structural model based on anisotropic beam finite element, in order to evaluate the coupled structural and the aerodynamic characteristics of the deformable proprotor blade. The numerical model was then validated by means of static performance measurements and shape reconstruction from Laser Distance Sensor (LDS) outputs. From the validation results of both aerodynamic and structural model, it can be concluded that the numerical approach developed by the authors is valid as a reliable tool for designing and analyzing the UAV-sized proprotor made of composite material. The proposed experiment technique is also capable of providing a predictive and reliable data in blade geometry and performance for rotor modes

Four Tilting Rotor Convertible MAV: Modeling and Real-Time Hover Flight Control

International audienceThis paper describes the modeling, control and hardware implementation of an experimental tilt-rotor aircraft. This vehicle combines the high-speed cruise capabilities of a conventional airplane with the hovering capabilities of a helicopter by tilting their four rotors. Changing between cruise and hover flight modes in mid-air is referred to transition. Dynamic model of the vehicle is derived both for vertical and horizontal flight modes using Newtonian approach. Two nonlinear control strategies are presented and evaluated at simulation level to control, the vertical and horizontal flight dynamics of the vehicle in the longitudinal plane. An experimental prototype named Quad-plane was developed to perform the vertical flight. A low-cost DSP-based Embedded Flight Control System (EFCS) was designed and built to achieve autonomous attitude-stabilized flight

Nonlinear Feedback Control of Axisymmetric Aerial Vehicles

We investigate the use of simple aerodynamic models for the feedback control of aerial vehicles with large flight envelopes. Thrust-propelled vehicles with a body shape symmetric with respect to the thrust axis are considered. Upon a condition on the aerodynamic characteristics of the vehicle, we show that the equilibrium orientation can be explicitly determined as a function of the desired flight velocity. This allows for the adaptation of previously proposed control design approaches based on the thrust direction control paradigm. Simulation results conducted by using measured aerodynamic characteristics of quasi-axisymmetric bodies illustrate the soundness of the proposed approach

Modeling and Control of mini UAV

International audienc

Automatic control of convertible fixed-wing drones with vectorized thrust

This paper proposes a control design strategy, encompassing trajectory tracking and path following, for a category of convertible aircraft with fixed wings and vectorized thrust, as exemplified by the Harrier jet aircraft and the V-22 Osprey. The approach relies on, and extends, previous works on the control of hovering vehicles (helicopters, quadrotors,...), ax-isymmetric devices (rockets, missiles,...), and fixed-wing aircraft (airplanes). In particular it exploits a common nonlinear model of aerodynamic forces exerted on the vehicle, both simple and representative of the underlying physics. Besides the unifying property of this approach, the proposed solution addresses the delicate transition problem between hovering and cruising flight, and thus the concomitant thrust tilting issue, in a novel manner with the possibility of continuously minimizing the thrust intensity, and thus energy expenditure

Development of the flight model of a tilt-body MAV

This article presents the results of a wind tunnel campaign for a tilt-body UAV, the MAVion. The objective of this campaign is to develop a simplified flight model for use in control systems design and implementation. In order to achieve precise flight control during transition, stationary and cruise modes, the aerodynamic coefficients are identified for a wide flight envelope of angle of attack and sideslip. Additionally, the equilibrium transition is studied and the results validate the MAVion design. Moreover, an analysis of performance on aerodynamics due to addition of winglets in this platform is carried out

Aeronautical design of a convertible VTOL unmanned aerial vehicle

Veículos aéreos não tripulados (VANT) conversíveis são capazes de atender missões complexas automaticamente se forem dotados de um sistema de controle de voo. O desenvolvimento de tais sistemas depende de uma plataforma de testes e validação que deve se comportar como um veículo aéreo não tripulado conversível. O projeto de tais aeronaves inclui questões únicas relativas à combinação de diferentes dinâmicas de voo, assim como questões específicas ao voo não tripulado. Este trabalho apresenta o projeto aeronáutico completo de uma aeronave não tripulada conversível que visa servir como uma plataforma de desenvolvimento de sistemas de controle de voo. A aeronave proposta é capaz de decolagem e pouso vertical e inclui dois modos de voo: asa-rotativa e asa-fixa. A aeronave é desenvolvida seguindo as três etapas clássicas de projeto aeronáutico (projeto conceitual, projeto preliminar e projeto detalhado). Uma análise conceitual é apresentada e os resultados das escolhas de projeto são analisados. Uma aeronave asa voadora tailsitter com baixa razão de aspecto, dois motores, dois ailerons e construção simplificada é proposta. A performance é analisada e características são definidas seguindo a metodologia típica de projeto aeronáutico. Os componentes da aeronave são projetados, detalhados, construídos, testados e validados. Os resultados incluem a pesquisa e desenvolvimento relativos a veículos aéreos não tripulados conversíveis, o projeto da aeronave proposta, um protótipo da aeronave, um modelo matemático e resultados de um voo inicial em malha aberta. Se concluiu que tal tipo de aeronave pode ser desenvolvida, que a performance obtida e as características de voo da aeronave proposta são aceitáveis e que o protótipo construído pode servir como plataforma de desenvolvimento de sistemas de controle de voo em trabalhos futuros.Convertible unmanned aerial vehicles (CUAV) can fulfill complex missions automatically if a flight control system is available. The development of such systems requires a platform for tests and validation that presents the same dynamic behavior of an actual CUAV. The design of such aircraft includes challenges related to the combination of different flight dynamics as well as to unmanned flight. This work presents the complete aeronautical design of a CUAV aircraft which serves as a development platform for flight control systems. The proposed design is a vertical takeoff and landing (VTOL) aircraft with two flight modes: fixed-wing and rotary-wing. The aircraft development follows the classical aeronautical design path (conceptual design, preliminary design, and detailed design). Conceptual analysis is presented and the design trade-offs are discussed. A flying-wing tailsitter aircraft with a low aspect ratio, two motors, two ailerons, and a simple build is proposed. The performance is analyzed and the aircraft characteristics are defined following the typical aircraft design methodology. The aircraft components are designed, detailed, built, tested, and validated. The results include research and development related to CUAV-VTOL design, the proposed aircraft design itself, a prototype of the design, a mathematical model, and an open-loop maiden flight. In conclusion, credible CUAV-VTOL designs are possible, the obtained performance and flight characteristics of the proposed aircraft are acceptable, and the built prototype can be used as a development platform for flight control systems in future works