Active control of airspring secondary suspension to improve ride quality and safety against crosswinds

Mechatronic technologies are increasingly adopted on railway vehicles, with particular reference to active secondary suspensions, as a means to improve vehicle performancein terms of ride safety and quality. This article presents the results of a theoretical and experimental research aimed at introducing active control capabilities in the pneumatic secondary suspension of a high-speed railway vehicle.The active airspring suspension is used, together with an active lateral suspension, to reduce passengers’ exposure to lateral acceleration in curves and to improve ride safety with respect to vehicle overturning in the presence of extreme crosswind. In this article, the active airspring concept is developed and suitable open- and closed-loop control strategies are proposed. Then, the results of an experimental characterization of the active suspension are reported, and based on these results a mathematical model of the vehicle with active suspension is defined. Finally, the active suspension performance is demonstrated by means of numerical experiments, showing the potential to bring substantial benefits in terms of both higher service speed for the same cant deficiency sensed by the passengers and increased ride safety.