Active vibration reduction in a light high speed train bogie

Vibration induced sound in the car of a light high speed train is of great interest since the light structure makes it more resonant. Low weight is important and and the aim is to decrease the weight of future trains significantly, compared to the X2000. Classical sound attenuation techniques are good for higher frequencies but active techniques are more suitable when lowering the low frequency induced noise in the car. This work therefore addresses a problem that is likely to occur in future trains, due to the decreased weight. The sleepers are a dominant excitation source for this case, and this implies a periodic excitation of 85 Hz when the train is running at 200 km/h. The sleeper frequency excitation will be an even larger problem when the car has a lower weight as well. This paper describes an active vibration isolation, or damping, where the goal is to reduce the sound inside the car due to the sleeper frequency excitation not the vibrations levels. Four actuators have been used and both an AVC as well as an ASAC control strategy has been tested and the results are presented. Tests have been performed on a full scale train in a lab as well as on track at approximately 200 km/h.