Abstract—An adaptive fault-tolerant sliding mode control is presented in this paper. A regular sliding mode controller is designed as the inner loop of the control structure, while in the outer loop the desired trajectory components are converted to the desired attitude. The problem of identification of the faulty subsystems’ dynamics is converted to the mathematical problem of determining the unknown coefficients of a Linear-In-Parameter (LIP) model. Subsequently, an effective observer is developed in the paper based on the well-known Online Sequential Extreme Learning Machine (OS-ELM) approach in order to identify the dynamics of faulty subsystems and afterward, a disturbance observer is proposed to estimate the effects of external disturbances on the dynamic model. Furthermore, the stability of the closed-loop system is analyzed based on the Lyapunov theorem. The introduced control structure is applied to a quadrotor Unmanned Aerial Vehicle (UAV) for tracking a predefined trajectory in the 3D environment. The simulation results demonstrate that using the proposed control scheme, the air vehicle can follow the desired trajectory in the presence of simultaneous actuator faults and external disturbances.
Index Terms—Adaptive control, OS-ELM, quadrotor UAV, sliding mode control, trajectory tracking.
S. A. Emami and A. Banazadeh are with the Department of Aerospace Engineering, Sharif University of Technology, Tehran, Iran (e-mail: Banazadeh@sharif.edu).
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Cite: Seyyed Ali Emami and Afshin Banazadeh, "Nonlinear Fault-Tolerant Trajectory Tracking Control of a Quadrotor UAV," International Journal of Modeling and Optimization vol. 9, no. 5, pp. 285-290, 2019.