Fault‐Observer‐Based Fault‐Tolerant Fuzzy Terminal Sliding Mode Control of a Quadrotor Encountered the Deviation of Rotor Thrust

ABSTRACT Due to the high nonlinearity of the quadrotor dynamics and the generated structural faults, a Fault‐Observer‐Based Fault‐Tolerant Fuzzy Terminal Sliding Mode Controller (FT2SMC) is utilized. This strategic utilization remains effective even when the system encounters input saturation. A fault observer estimates the fault vector since it is applied to the governing equations of motion as external disturbances. Additionally, a Fuzzy Inference System (FIS) has been employed to estimate the discontinuous term of the terminal sliding mode control and to alleviate the chattering phenomenon. The finite‐time convergence of the tracking errors of the attitude and the altitude toward the origin has been guaranteed, and the entire closed‐loop stability of the faulty quadrotor has been proved using Lyapunov theory, ensuring that it continues following the desired trajectory even in the presence of faults. The simulation results indicate the prodigious effectiveness of the controller, which navigates the quadrotor to a desired altitude. Also, the superiority of this control algorithm is demonstrated by comparing the results of the control inputs with those obtained with a regular terminal sliding mode controller.