Study of H.INF. Controlled Active Suspensions for Railway Vehicles.

Recently in railways, lightweight vehicles have been used in order to save transport energy. This tendency is notable especially in high-speed railways. However, the flexibility of such vehicles sometimes induces deterioration of ride quality. Therefore, to obtain high ride quality, an H∞ control method for an active suspension system in rail cars is proposed. In design of the H∞ controller, it is necessary to determine suitable weighting functions so as to achieve a special frequency band at which high ride quality can be attained. Additionally, in this controller, robust stability against modeling errors such as changes in vehicle weight or disregard of high-frequency resonances must be pursued. The effects of H∞ active suspensions are confirmed by digital simulations.