Active vibration control of a railway pantograph

Current collection for electrical trains can be improved by the use of an active pantograph. To design such a system the behaviour of both the active pantograph and the overhead catenary system must be considered together. In this paper a two degrees-of-freedom model of an active pantograph, combined with a time-varying spring representing the catenary's influence, is employed and its dynamic performance is studied. Based on this model, three types of control strategies for an active pantograph are proposed and investigated, and all these models consider the interaction of the pantograph with the overhead wire. Two possible positions for mounting an actuator on the pantograph are considered and compared. From these active pantograph models the magnitude of the control force required can be estimated, and the advantages and disadvantages are discussed. The optimal control strategy shows the best performance, but introduces measurement difficulties because it needs full-state feedback. Classical feedback control is the least difficult to implement, but a compromise between the stability and the performance should be reached.