Prior-Information-Based Finite-Frequency H∞ Control for Active Double Pantograph in High-Speed Railway

The fluctuation in contact force between the pantograph and the catenary severely affects the current collection quality of electric multiple units in high-speed railway. In particular, when double pantographs operate simultaneously, the contact force on trailing pantograph (TP) fluctuates violently due to the passage of leading pantograph (LP). To address this problem, a prior-information-based finite-frequency textH ∞controller, incorporating an adaptive estimator, is proposed for the active control of double pantographs in this paper. As the prior information is of great importance, the frequency characteristics of contact force are analyzed based on power spectrum density and utilized in calculating the control gain matrix. The finite-frequency control is employed to decrease the contact force fluctuation within the concerned frequency range with limited control force. Considering the unknown and time-varying noise statistic, an adaptive cubature Kalman filter is presented to estimate the states of pantographs. The effectiveness and robustness of the proposed control strategy are evaluated with implementations in a nonlinear double-pantograph-catenary system model under different operational conditions. The results show that, for both LP and TP, the control strategy can adequately decrease the contact force fluctuation. Particularly, it has a good capability to reject parameter perturbations and external disturbance.