“…The second concern of handling unmatched uncertainty is justified because it has been observed that the major uncertainties present in many MCS such as rail track input in MAGLEVs, 28 load torque in PMSM, 29 external wind disturbances in flight control system, 30 and so on do not adhere to so-called matching condition and hence robust performance out of SMC may not be achieved. 31 Hence, due to the importance of nullifying mismatched uncertainties for getting precise and effective performance from MCS, many decent SMC strategies focusing the mismatched disturbance attenuation have been reported in the literature, for example, Riccati based approach, 32 LMI-based, 33 H ∞ control based, 34 adaptive approach, 35 and so on. However, these approaches are designed to handle mismatched uncertainties if they are vanishing type, that is, H 2 norm-bounded which may not be the case in real-time system, for example, in MAGLEV transportation system, the considered lumped uncertainties may not have zero steady-state and hence not H 2 norm-bounded.…”