Abstract
The authors have been studying on the method for reduction in contact force fluctuation between catenary and pantograph using variable stiffness devices. The normal pan springs of the pantograph are replaced by the devices utilized in this study. It is possible to improve the current collection performance by varying the stiffness of the device in such a way that the peak frequency of pantograph's mechanical compliance is consistent with the dominant frequency of the disturbance to the pantograph. We produced a prototype of the device and mounted it on a pantograph. The device is composed of two air springs and is capable of varying its stiffness by changing the air pressure. However, its stiffness is biased by the rubber parts of the air springs so that the controllable peak frequency range of the pantograph's mechanical compliance is limited only in higher frequency region. The rubber parts cannot make thinner to reduce its stiffness contribution to the device because it is necessary for the device to retain pressure capability. In order to overcome abovementioned problem, we propose the other type of variable stiffness device which actually is a pneumatic cylinder. The device has lower stiffness without losing pressure capability. The pantograph with this device indicates better performance in terms of the controllable peak frequency range of the mechanical compliance.
