This editorial article gives a short introduction to Special Issue of International Journal of Control on Adaptive Sliding Mode Control and Observation.

Output tracking in causal nonlinear systems with an output time delay is considered using sliding mode control. The problem is reduced to that of the tracking of the output reference profile given by an exogenous system in a causal non-minimum phase system without delay, where the delay is being replaced by its Pade’ approximation. The non-minimum phase output-tracking problem is transformed to a corresponding state tracking problem. Bounded state tracking profiles are generated by equations of the stable system center. A sliding mode control algorithm is developed. A numerical example demonstrates the effectiveness of the sliding mode control design.

This paper uses the recently developed sliding mode control driven by sliding mode disturbance observer approach to design a robust flight controller for a small quadrotor vehicle. This technique allows for continuous control robust to external disturbance and model uncertainties to be computed without the use of high control gain or extensive computational power. The multiple-loop, multiple time-scale flight controller is designed to provide robust position and attitude control of the vehicle while relying only on knowledge of the limits of the disturbances. Extensive simulations of a 6 DOF computer model demonstrate the robustness of the control when faced with external disturbances (including wind, collision and actuator failure) as well as model uncertainties.