Development of an autonomous unmanned aerial vehicle specification of a fixed-wing vertical takeoff and landing aircraft

• Autor(a) principal: Silva, Natássya Barlate Floro da
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: http://www.teses.usp.br/teses/disponiveis/55/55134/tde-16102018-100220/
• topic: Algoritmos de seguimento de trajetória; AVALON; AVALON; Controle para VANTs; Fusão de sensores; Path-following algorithm; Sensor fusion; Tailsitter; Tailsitter; UAV control

Several configurations of Unmanned Aerial Vehicles (UAVs) were proposed to support different applications. One of them is the tailsitter, a fixed-wing aircraft that takes off and lands on its own tail, with the high endurance advantage from fixed-wing aircraft and, as helicopters and multicopters, not requiring a runway during takeoff and landing. However, a tailsitter has a complex operation with multiple flight stages, each one with its own particularities and requirements, which emphasises the necessity of a reliable autopilot for its use as a UAV. The literature already introduces tailsitter UAVs with complex mechanisms or with multiple counter-rotating propellers, but not one with only one propeller and without auxiliary structures to assist in the takeoff and landing. This thesis presents a tailsitter UAV, named AVALON (Autonomous VerticAL takeOff and laNding), and its autopilot, composed of 3 main units: Sensor Unit, Navigation Unit and Control Unit. In order to choose the most appropriate techniques for the autopilot, different solutions are evaluated. For Sensor Unit, Extended Kalman Filter and Unscented Kalman Filter estimate spatial information from multiple sensors data. Lookahead, Pure Pursuit and Line-of-Sight, Nonlinear Guidance Law and Vector Field path-following algorithms are extended to incorporate altitude information for Navigation Unit. In addition, a structure based on classical methods with decoupled Proportional-Integral-Derivative controllers is compared to a new control structure based on dynamic inversion. Together, all these techniques show the efficacy of AVALONs autopilot. Therefore, AVALON results in a small electric tailsitter UAV with a simple design, with only one propeller and without auxiliary structures to assist in the takeoff and landing, capable of executing all flight stages.