Control validation with softwareintheloop for a fixedwing vertical takeoff and landing unmanned aerial vehicle with multiple flight stages Unmanned Aerial Vehicles (UAVs) are aircraft without a human aboard that can fly autonomously or be remotely piloted. Several configurations of UAVs have been developed to fulfill the requirements of different applications. Between them, it is possible to highlight the tailsitter, a hybrid design with the advantages of fixedwing and Vertical TakeOff and Landing (VTOL) aircraft. A tailsitter UAV with simplicity as its main characteristic is AVALON (Autonomous VerticAL takeOff and laNding), which also has the disadvantage of a complex operation due to its multiple flight stages. To enable its autonomous procedure, AVALON requires a control system capable of stabilising the flight during its entire operation. Therefore, this paper reports the validation of control structures based on proportionalderivative controllers for AVALONxe2x80x99s flight stages with softwareintheloop experiments in the flight simulator XPlane. The results show small errors for most of the flight stages, with the exception of landing. Despite of being able to land vertically, it still presented large errors and a yaw variation during this last stage.

Precision Modeling and Optimallysafe Design of Quadcopters for Controlled Crash Landing in Case of Rotor Failure The seminal work cited in 1,2 showed, for the first time, that flight stability of quadcopters would be possible in case of one or even multiple rotor failures. However, the quadcopter can remain airborne only by going through a spinning maneuver about an axis, fixed w.r.t the vehicle (i.e., resolved yaw). Furthermore, positional control can be achieved by periodically tilting this axis. This paper builds upon this concept with two major improvements: (1) introducing a precise aerodynamic model of propellers that takes the flapping torque due to unbalanced lifting force in the advancing and retreating blades subjected to freestream, into account, and (2) adding to the stability and flight efficiency of the quadcopter by introducing symmetric fixed tilting angles to the trust vectors. In our previous work 3, it was shown how the flight stability and energy efficiency can be improved by introducing fixed tilting angles in the thrust vectors. For controlled crash landing in case of one rotor failure, where a resolved yaw maneuver would be inevitable, introducing a titling angle in rotors can generate a reasonable resolvedrateyaw spinning speed to keep the quadcopter airborne at a lower rotational speed of the blades by taking advantage of the freestream generated by spinning. This tilting angle would also lead to passive stability in yaw motion of the quadcopter before the failure. Our hypothesis was successfully tested via simulations.