Control System Design for Tiltable Quad-rotor with Propeller Failure

The traditional quad-rotor UAV is an under-driven system, and it is difficult to ensure stability when the actuator fails. In this paper, a new mechanical structure is adopted on the traditional quad-rotor to enable the rotors to tilt around the arm that the 4 additional actuated dofs are added and the full controllability over the quad-rotor attitude is obtained. The dynamics and kinematics models of the quad-rotor with the new structure are established and be linearized at a given equilibrium point. Based on the linearization model, the controller based on the linearized feedback method is designed to stabilize the system when the two opposing propellers failed. Numerical simulation and a quad-rotor prototype experiment are provided to verify the effectiveness of the proposed new mechanical structure and control algorithm.