Abstract
It becomes difficult for a current collector of high-speed railways to maintain constant contact force between the contact strip and the trolley-wire, since it suffers strongly from wire and lift disturbances in high-speed. Accordingly, it is necessary to control the height of current collector. Electrical sensors can be installed only below the insulator, since the upper part of the insulator is located in high voltage. In this paper, it is clarified to be difficult to distinguish wire disturbance from lift one in low frequency range. However, this difficulty is solved by separating the frequency range of these disturbances. Two kinds of contact force control using H∞ control theory are presented in this paper. One is a servo H∞ controller of contact force using the lift estimated from drag. This controller can reduce the contact force variation due to wire disturbance at the frequency range less than 1.5Hz, and the contact force due to the lift can be reduced if the lift is estimated exactly through the drag force. The other is a H∞ regulator which estimates those disturbances in the separated frequency ranges. This controller can reduce the contact force variation due to the wire disturbance at the frequency range from 0.2Hz to 6Hz compared and contact force variation due to the lift at less than 0.1Hz. Furthermore, it is confirmed that if a sensor can measure the displacement of contact strip, contact force can be controlled better against those disturbances.
