Fabio Ruggiero's website
Both a PID approach here and a backstepping one here have been proposed to cope with the failure of a quadrotor’s propeller. The presented methodologies suppose to turn off also the motor which is opposite to the broken one. In this way, a birotor configuration with fixed propellers is achieved. The birotor is hence controlled to follow a planned emergency trajectory. In truth, in both cases, theory shows that any point in the Cartesian space can be reached, provided that the possibility to control the yaw angle is lost.