Extended State Observer Based Integral Sliding Mode Control for Maglev System With Fixed Time Convergence

The purpose of this study is to explore the design of a robust control strategy for regulating the magnetic levitation system, which is affected by model uncertainty and surrounding disturbance. This paper integrates a fixed-time extended state observer (ESO) with a fixed-time integral sliding mode control (ISMC) design. The fixed-time ESO is employed to estimate the total disturbance within the system in a fixed time. The estimated output is then fed to the composite control law to cancel the actual disturbance in the system. Consequently, it avoids large gain for switching function in the ISMC law, thus suppressing the chattering from the control input. It also avoids employing a conservative condition on the advance information of disturbance bound. In addition, the proposed ISMC design ensures fixed time convergence of closed-loop signals. Moreover, since the integral sliding surface has no reaching phase; therefore the proposed composite scheme has a better invariance behavior from the initial time. The Lyapunov stability theory proves the fixed time stability of sliding variable and relative states. Furthermore, the effectiveness of the presented methodology is validated using numerical analysis with a comparative performance of state-of-the-art control schemes. The numerical results of these schemes are judged based on convergence time, residual bound, energy consumption, and total input variation.