Robust IFNTSM–ESO Control Design for Aircraft Subject to Parameter Uncertainties

A comprehensive strategy that combines improved fast nonsingular terminal sliding mode (IFNTSM) control and an extended state observer (ESO) is developed to solve the problems of uncertainty in the aeronautical field. First, the IFNTSM control method is proposed to solve the singularity problem and guarantee a faster finite-time convergence speed. Second, an ESO is introduced to estimate the parameter uncertainties, and then a control scheme that combines IFNTSM and ESO is developed to overcome the drawback of large switching gains in a sliding mode controller and alleviate the chattering problem. The stability of the composite system is analyzed via the Lyapunov stability theorem. Finally, the simulation demonstrates that the composite controller accelerates the convergence speed and offers excellent robustness for complex parameter uncertainties.