Fault Tolerant Control of a Quadrotor Helicopter Using Model Reference Adaptive Control

This paper proposes a useful approach to Fault Tolerant Control (FTC) based on the Model Reference Adaptive Control (MRAC) technique with application to a quadrotor helicopter Unmanned Aerial Vehicle (UAV) in hovering as well as trajectory tracking flight in order to control and keep the desired height and trajectory of the quadrotor helicopter in both normal conditions and in the presence of faults in one or more actuators. A Linear Quadratic Regulator (LQR) controller is used in cooperation with the MRAC to control the pitch and roll attitude of the helicopter. Three cases of fault are considered: 1) simulated fault in all the four actuators; 2) simulated fault in back and right motors; 3) a physical damage of 23% of one of the four propellers during autonomous flight. It can be seen from the test results that under the faulty and damage conditions MRAC controller provided a good response of the quadrotor UAV and result in safe landings of the quadrotor.