Active vertical vibration suppression of high-speed railway vehicles by controlling internal pressure of the air spring using μ-synthesis control

In recent years, railway vehicles have become lighter since it corresponds not only to the improvement of the running speed but also to the reduction of running cost and environmental noise. On the other hand, this causes an increase in the vertical elastic vibration of the car body and the riding comfort has deteriorated. Therefore, various strategies to reduce vertical vibration have been studied. In this study, vertical vibration reduction, by controlling the internal pressure of the air spring using mu-synthesis control, is proposed. The merit of mu-synthesis control is that it can guarantee robust performance. A controller by mu-synthesis was designed for vibration reduction of a 1/6 scale railway model and compared nominal performance and robust performance with H8 control theory. Moreover, a feasibility study of this strategy was investigated for full-scale railway vehicles through simulation.