Robust Adaptive Control Based on Incremental Nonlinear Dynamic Inversion for a Quadrotor in Presence of Partial Actuator Fault

In this paper, a nonlinear robust adaptive trajectory tracking control architecture based on Incremental Nonlinear Dynamic Inversion (INDI) is introduced to stabilize and control a quadrotor in presence of actuator partial fault. In a novel approach, a three-loop cascade architecture of the controller is proposed. The INDI algorithm is applied as the baseline controller in the inner-loop and a nonlinear model reference adaptive controller is augmented in the outer-loop to provide robustness for the unmodeled fault in the inner-loop. In the proposed control strategy, a modified PID controller is introduced in the most outer-loop for tracking the desired path. The fault effect has been modeled by considering the sudden variations of motor thrust and torques. To increase the robustness of the control algorithm the projection operator has been applied in the robust adaptive structure. The performance of the proposed controller is compared with a previous successful algorithm, which had been implemented on a quadrotor model. The results demonstrate that the proposed controller can provide full controllability of the desired faulty quadrotor in pitch, roll, and yaw channels in presence of partial fault of actuator up to 50%.