Control strategies to improve ride quality in railway trains

Design of railway active suspensions for ride improvement is currently based upon controlling an isolated carriage within a train without taking into account dynamic interaction from adjacent vehicles, and a knowledge of the track disturbance from vehicles upstream of the vehicle under consideration. This paper aims to combine these two deficits, by considering full train dynamics, and by applying control laws which have a knowledge of the highly correlated time-delayed track input. Current thinking encourages the use of secondary actuators to inject ride improving forces into the system. An alternative approach is to use inter-vehicle actuators to inject controlling forces into the system. Such an arrangement is also looked at. The aim therefore is to produce a less conservative design for the ride controller which give us an improvement in ride quality over existing techniques. The use of inter-vehicle actuators will reduce the number of actuators required, and their bandwidth requirement.