Active control of secondary airspring suspension

This paper 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 provide a limited carbody tilt, reducing passengers’ exposure to lateral acceleration in curves and hence allowing to raise service speed on existing high speed lines. To this aim, a suitable control strategy is defined for the active suspension, based on the combination of open-loop and closed-loop control, and the parameters of the actuation and control system are optimised using simplified models of the actively controlled vehicle. The active suspension concept is then demonstrated by means of laboratory tests performed on a full-scale test stand consisting of one bogie with active pneumatic secondary suspension and of a ballast mass reproducing the inertia of half carbody. The numerical and experimental results obtained show the potential of the proposed active suspension to meet the targets set for the investigation.