Nonlinear Robust Composite Levitation Control for High-Speed EMS Trains With Input Saturation and Track Irregularities

Abstract

Unavoidable track irregularities continuously excite a traveling high-speed electromagnetic suspension (EMS) train. This issue deteriorates the levitation performances such as stability and comfortability. A robust levitation controller is critical for the EMS unit to suppress irregularities. In this work, a novel composite control scheme is proposed for high-speed maglev trains. It combines a fixed-time disturbance observer (FTDO) and a global finite-time controller (FTC). The FTDO is designed to estimate irregularities precisely within desired bandwidth, while the FTC is to address the fast dynamics of the levitation system of a high-speed maglev train. In addition, the command filter is integrated to increase the practicability of the composite control scheme. Theoretical analysis establishes the stability of the whole system. With ideal irregularity models and the field data measured from a commercial line, numerical simulations under various operation scenarios, including high speed, time-varying speed, gust and slope, verify that the proposed control scheme improves the air gap response while maintaining the stationarity of primary levitation and the ride comfortability for passengers. The simulations on a full bogie with load also demonstrate effectiveness of the proposed scheme.