The lateral suspension of a railway vehicle contains a diversity of dynamic elements, ranging from secondary suspension airbags to primary suspension wheelset dynamics. An active suspension can be applied to the lateral secondary suspension with the aim of improving passenger ride quality, however the active secondary suspension interacts with the primary suspension dynamics of the vehicle and it is important that these dynamics are considered when designing active control laws. Previous work in the area has concentrated on applying control techniques to low order models which neglect important dynamic behaviour purely for reasons of simplicity. This paper considers a much more accurate lateral model, and applies three active control techniques to it, namely linear optimal control, complementary filter control, and semi-active control. The merits of each of these control strategics will be addressed in terms of their ride quality improvement and practicality of implementation.
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