2020 年 86 巻 881 号 p. 19-00251
The railway current collection system consists of a line and a pantograph. We take up the problem of the contact loss between a rigid conductor line and a pantograph. In order to avoid the damage on the line surface by the electric ark, it is important to prevent the contact loss. From the series of experiments with an actual pantograph system, an essential model that regards the contact loss as impact oscillations between a rigid conductor line and a pantograph was proposed. This model consists of a spring supported mass and an external exciting source that is pushed against the mass. In this paper, in order to suppress the impact oscillations, we add an oscillatory system coupled to the spring-mass system. Then, we consider the impact oscillations between the excitation source and the main mass in the two-degrees-of-freedom system. We numerically investigate the problems and obtain the bifurcating motions. When the exciting frequency is near the second mode natural frequency in the two-degrees-of-freedom system, the impact oscillations between the main mass and the external excitation source is suppressed. We conducted a series of experiments in order to verify the theoretical results. The experimental results also reveal the suppression of the impact oscillations. The experimental results qualitatively well agreed with the theoretical predictions.
