Torsional Vibration Reduction of Railway Vehicle by Controlling Internal Pressure of Air Springs Using H-Infinity Control

As railway vehicles become faster and lighter, the vibration of car body tends to increase and that makes the ride comfort worse. In lateral and vertical rigid-body vibration, a number of reduction technologies have been put into practical use, such as semi-active suspensions and variable vertical dampers installed between car body and bogie. In elastic vibration, various methods have been studied, such as control by previously mentioned dampers, stack-type piezoelectric actuators. However, these methods focused on only the bending vibrations, it has been difficult to reduce multiple elastic vibration modes simultaneously. The authors propose a method to simultaneously reduce multiple elastic vibration modes, including torsional vibration, by controlling internal pressure of air springs. Since this method uses existing devices, it is superior in weight, cost, and maintenance compared to installing a new vibration compensator. First of all, we developed railway vehicle analytical model that can express elastic vibration including torsional vibration. Furthermore, we designed a control system by H-infinity methods and verified vibration-reduction effect on the stationary excitation test of simple railway vehicle model. As a result, it was confirmed that multiple elastic vibration modes, including torsional vibration, can be reduced simultaneously.