Stability Analysis of High-Speed Truck Having New Conception Steering and Z-N-Link Suspension Device Mechanism

It is empirically known that a railway vehicle is by nature, characterized by contra-dictory behaviors on a tangent track and on curves. Hence, it becomes clear that the Z-link-equipped vehicle, which is intended to improve the passing performance on curves, has a slight forward expansion of the unstable region of body hunting in comparison with traditional vehicles. In order to improve this hunting unstability, the steering truck with a unique mechanism, Z-N-link suspension device mechanism, has been developed, which contributes to enhancement of good running performance both on the tangent track and on curves. On the basis of the theoretical analysis, it is recognized that adequate supporting stiffness at the point of connection between N-links is an effective means of increasing the hunting velocity, and that there exist two limit cycles, that is, one is an unstable limit cycle and the other is a stable one. In this paper, a new concept of the steering truck is given, which provides guidelines of future design of high-speed trucks.