Tilt-Rotor Quadcopter Xplored: Hardware based Dynamics, Smart Sliding Mode Controller, Attitude Hold & Wind Disturbance Scenarios

This paper provides insights on the tilt-rotor quadcopters being a fully actuated system. The tilt-rotor quadcopters are a novel class of quadcopters with the capability of rotating each arm/rotor of the quadcopter to an angle using a servo motor. With the additional servo control inputs, the tilt-rotor quadcopters are fully actuated systems and hence can even hover at any desired orientation. The dynamics of the tilt-rotor quadcopters are derived based on hardware developed in the laboratory with minimal assumptions. A novel nonlinear sliding mode controller is designed that provides the controller input values to achieve any orientation and position as desired. Computational Fluid Dynamic (CFD) simulations were performed on a CAD model of the tilt-rotor quadcopter to obtain real time drag forces for various wind velocities. The robustness of the sliding mode controller is demonstrated under various wind disturbance scenarios while the quadcopter is hovering at a desired position and attitude.