Fractional order predictive sliding-mode control for a class of nonlinear input-delay systems: singular and non-singular approach

摘要

Nonlinear models of physical systems usually suffer from input delay and external disturbances. Moreover, when a delayed state is in the input signal gain, it can be non-singular or singular. So, designing a robust controller in a nonlinear system with input and state delay, suitable for non-singular and singular input signal gain, is imperative. The main contribution of our study is to design a new state feedback fractional order predictive sliding mode control (FOPSMC) procedure which not only guarantees the stability of a nonlinear system with known constant input and state delay but also controls the output signal to the desired value. Firstly, a predictor is designed for the system to achieve an input-delay-free one. Then, a state feedback FOPSMC is proposed based on a fractional order sliding signal for a nonlinear system with non-singular control gain. Also, a state feedback FOPSMC and a fractional order sliding mode observer (FOSMO) for the virtual disturbance are designed for singular control gain situation. It is proved analytically, through the Lyapunov stability criteria, that both control procedures can stabilise the system and can control the output signal to the desired value, effectively. Finally, the simulation results verify the effectiveness of the analytical achievements.