Discrete fuzzy variable structure control for pantograph position control

A discrete fuzzy variable structure control is developed for high-speed rail pantograph position control systems in the presence of system uncertainty and external perturbation. The proposed method gives a simple and effective tuning algorithm for the control law. The switching surface is defined using the system output signals. The stability of this control system is guaranteed and robust output performance is ensured. The closed-loop eigenvalues are placed stable. The control system is guaranteed driven to the quasi-sliding mode. Fuzzy logic serves to detect and accommodate the unexpected perturbation.