Active Fault Tolerant Control for a UAV Subject to Sensor Faults Using Sliding Mode Control

Unmanned aerial vehicle (UAV) pitch tracking control in the presence of pitch rate gyro sensor faults is addressed in this work using sliding mode control (SMC). Fault estimation is carried out using two different observers, a high gain observer (HGO) and a radial basis function neural network (RBFNN). Real-time fault estimations are used in the control law to counter the effects of the faults. The chattering problem of SMC is resolved using a power reaching law in the switching part of the control. This forms an active fault tolerant control without the need for controller reconfiguration. The stability of the faulty system is proved using the Lyapunov method. The proposed strategy is applied to pitch tracking control of a scaled Yak-54 UAV. The simulation results show the effectiveness of the proposed methodology.