ABSTRACT

When designing articulated tractor-trailer systems, engineers should take care to contrast some undesired phenomena associated with the lateral dynamics: the path off-tracking, namely the trajectory deviation of the points of the two units compared to the midpoint of the tractor fore; the rearward amplification of the transverse acceleration. The off-tracking may lead the vehicle tail to invade the opposite direction lane or the emergency lane, whereas the rearward amplification may involve the danger of the trailer rollover. Nonetheless, the arrangement of multi-steering axle systems with the proper correlation among the steering angles may substantially cancel the off-tracking, both along a path with constant curvature and while entering or leaving the road bend. Moreover, the proper control of the increase and decrease of the steering angle during the transient phases can restrain the lateral acceleration of the towed unit. The present analysis considers several nonlinear effects of the vehicle lateral dynamics, such as large steering angles, nonlinear cornering characteristics and changes of the cornering forces because of the centrifugal effect. The goal is a practical formulation of the correlation among the steering angles to correct the vehicle run and ensure lateral stability.

摘要

在设计铰接式拖拉机-拖车系统时，工程师应注意对比与横向动力学相关的一些不良现象：路径偏离轨道，即两个单元的点相对于拖拉机前部中点的轨迹偏差；横向加速度的向后放大。跑偏可能导致车辆尾部侵入对向车道或应急车道，而后向放大则可能涉及拖车翻车的危险。尽管如此，在转向角之间具有适当相关性的多转向轴系统的布置可以在沿着具有恒定曲率的路径以及在进入或离开道路弯道时基本上消除偏离轨道。而且，在瞬态阶段适当控制转向角的增减可以抑制被牵引装置的横向加速度。目前的分析考虑了车辆横向动力学的几种非线性效应，例如大转向角、非线性转弯特性以及由于离心效应引起的转弯力的变化。目标是对转向角之间的相关性进行实际公式化，以校正车辆行驶并确保横向稳定性。