Sliding mode control for comfort improvement in railway vehicles

There already exist various investigations in the field of comfort improvement with the help of actuators in the secondary suspension. They are often based on the assumption that only track set irregularities but not trace are chosen as a disturbance variable of the system. The first part of this contribution describes how to ensure a comfortable journey along a track with inclination changes and no track set irregularities, using information on the trace and current vehicle position. If this technique is combined with comfort optimisation methods to control short-wave irregularities, the nonlinear parts of the characteristic curves of the spring and damper elements are used. The application of successful comfort optimisation methods, notwithstanding these nonlinearities, with the aid of Sliding Mode Control is given in the second part of the paper.