Passive and Semi-Active Airspring Suspensions for Rail Passenger Vehicles—Theory and Practice

The performance of passive and semi-active secondary airspring suspension systems on rail passenger vehicles has been studied theoretically and experimentally. Classical and modern optimal control theory was utilized in the studies. The concept of the semi-active damper was realized in a laboratory test by a butterfly valve, for which a practical position control logic was developed. The quarter vehicle test rig results have shown that by making the orifice damper variable, a 29 per cent ride improvement has been achieved. For the full vehicle computer simulation, a ride improvement of 20 per cent has been achieved. In addition, for both cases, the dynamic suspension working space has been reduced by 10 per cent.