Rail Vehicle Active Suspensions for Lateral Ride and Stability Improvement

The potential performance benefits of simple, low power active elements in the lateral secondary, between the truck and carbody is investigated analytically by parametric studies utilizing a fifteen degree of freedom lateral dynamic model subject to alignment and cross-level inputs. It is shown that significant improvements in ride quality can be obtained at current operating speeds by using less than 3 kw per truck by sensing lateral carbody accelerations and utilizing lateral force actuators between the truck and carbody. It is also shown that in order to improve the truck critical speed and/or to improve the ride quality at very high speeds requires control of the truck kinematic mode. This can be achieved, at the expense of increased power requirements, by sensing absolute truck lateral and yaw velocities and utilizing combined lateral force actuators to exert a yaw moment on the truck. It is concluded that significant ride quality improvements can be achieved by low power, small bandwidth actuators while stabilty improvements requires increased power and larger bandwidth systems.