Potential of Active-Steering Bogie for Reducing Lateral Axle Load Caused at Worn Welded Joints of Outer Rail in Curved Track

摘要

This paper deals with the potential of an active-steering bogie to reduce the large lateral axle load that arises at worn welded joints of the outer rail in a curved track when high-speed trains pass. The shape of the worn joint, called lateral ‘angular bent’, is modeled on the basis of the measured irregularity shape of actual joints. Then, numerical simulation of running on a curved track is carried out for a two-axle bogie vehicle to compare an active-steering bogie and a conventional nonsteering bogie. The behavior of the vehicle negotiating the curve is evaluated from the viewpoints of decreasing the peak value of lateral axle load within the allowance limit and maintaining the running stability. To satisfy the requirements, wheelset-supporting parameters and feedback gains for active-steering are optimized on a curved section of 400 m radius by the Genetic Algorithm. On the basis of the optimized wheelset-supporting parameter values, additional sets of feedback gains, which are adjusted for the curves of different radii, are proposed. The numerical simulation shows that the operation speed of a vehicle with active-steering bogies having the optimized parameter values has the potential to be raised to the possible speed for tilting trains while satisfying the criterion of riding comfort.