The paper presents a study of an active yaw relaxation system in which conventional traction rods are replaced with an active design, the lengths of which can be varied in a controlled manner. Various control strategies have been tried, and these have been assessed on the basis of transition and steady-state curving perfomance. The most significant discovery is that a very simple control law, the objective of which is to reduce the steady-state wheelset yaw moment to zero, is extremely effective at improving curving performance. The strategy achieves 'ideal' curving on large radius curves for which there is sufficient rolling radius difference, and significant improvements even where flange contact is inevitable. Under the latter condition it was found that it is better not to control the trailing wheelsets, but this has led to a more advanced strategy in which two wheelsets in a bogie are controlled in a coordinated manner. Actuator power levels, albeit under ideal conditions, have been shown to be very low. A useful development of the study would be to determine how well the concept works with a higher coinicity wheel profile, which would of course require increased longitudinal stiffness to ensure stability. Normally this would counteract the ability afforded by the higher conicity to negotiate tighter curves, but the active yaw relaxation will ensure the increased rolling radius difference can be exploited. Having established the viability of the concept of active yaw relaxation, the next stage will be to use the results to undertake an outline design of suitable actuators, to extend the modelling of the system to include the practicalities of a real actuator and to assess how this affects the performance.
Active yaw relaxation for improved bogie performance
Vehicle System Dynamics ; 28 , 4-5 ; 273-289
1997
17 Seiten, 17 Bilder, 4 Tabellen, 6 Quellen
Article (Journal)
English
Active Yaw Relaxation For Improved Bogie Performance
Online Contents | 1997
|Active yaw relaxation for improved bogie performance
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