Modelling, Design and Simulation of a Quadrotor with Tilting Rotors Actuated by a Memory Shape Wire.
Henrique Bezerra Diógenes1; Davi Antônio dos Santos1
1 Instituto Tecnológico de Aeronáutica
doi:10.20906/CPS/CON-2016-0452
Resumo
This paper deals with a quad rotor hovercraft provided with a mechanism based on a memory shape alloy witch allows tilting the rotors angles. Thus the thrust force vector of each propeller can assume two possible directions: perpendicular to the plane formed by the center of the rotors or tilted inwards. The performed analysis shows that with the second set the vehicle has greater stability and higher agility horizontally, while with the first, the energy consumption is lower and the vertical acceleration is higher. The vehicle's dynamics was studied both analytically and by simulations using MATLAB/Simulink in order to compare the two possible configurations. Based on the analytical study, it is shown that the internal inclination of the rotors, combined with the placement of the vehicle's center of mass below the propellers plane, allows an increase on the maximum torque applied by the controller to establish attitude. Also, when tilting the rotor, perpendicular forces to the hovercraft plane appear. A change in the conventional control law allows these forces to be used, improving performance. Three different scenarios were performed by simulation. In the first scenario, with the MAV hovering, it was measured the time it takes to move horizontally to a certain position. In the second scenario, an initial attitude inclination was applied to the hovering Micro Aerial Vehicle (MAV) and the time until stabilization was measured. The MAV with tilted rotors showed better results in the first scenario, wile the conventional configuration showed better performance in the second scenario. The third simulation revealed that the act of tilting the rotors does not change the MAV's position significantly.
Palavras-chave: Quad Rotor Hovercraft; Dynamic Model; Memory Shape alloy; Aerial Robotics