车辆侧翻倾向动态测试的研究(一)

为了定量分析车辆的侧翻倾向,必需开发一变工况下预测车辆侧翻可靠的动态测试方法。本文介绍车辆侧翻稳定性方面已经开发的动态测试的一些成果。开发车辆侧翻倾向的测试,必需首先确定车辆侧翻所绕的轴线(侧翻轴)的位置。为此应首先进行中心轴概念的研究。如本文所述表明,车辆中心轴位置是不可预测的,导致三种可能的侧翻轴的分析,要进行车辆系统的动能和势能,和其部件变形造成的结果以及过去开发的能量基础函数所谓侧翻防止能量储备(RPER)的研究。RPER的定义为车辆到达侧翻位置所需的能量和车辆回转运动能量可转换成举升车辆的重势的差值。根据这种定义,在车辆侧翻情况下,在到达侧翻位置前,RPER函数值应降至零,通常在非侧翻情况RPER常为正值。本文介绍了开发的计算RPER的算式。RPER函数已经被Missouri-Columbia大学,采用全尺寸6辆轻型货车,箱式载货车和轻型箱式越野车辆以及二辆轿车,在不同的控制和侧翻掉纵过程的扩展试验获得的试验结果证实。试验时还采用的路边几何状况,包括路面铺土到铺石子的过渡段。本文对两侧翻和非侧翻情况绘出RPER的性能曲线。

An Investigation Into Dynamic Measures of Vehicle Rollover Propensity

A reliable dynamic measure to predict vehicle rollover under various conditions must be developed in order to quantitatively analyze the rollover propensities of vehicles. Several efforts have been made and are introduced in this paper on the development of such a dynamic measure of vehicle rollover stability. The position of the axis about which a vehicle rolls over （rollover axis） must be determined prior to developing a vehicle rollover propensity measure. For this reason, an investigation into the central axis concept was first performed. However, as shown in the paper, the unpredictability of the central axis position of the ve- hicle leads to the analyses of three other possible rollover axes. Investigations into the kinetic and potential energies of the vehicle system and its components have resulted in the modification and the extension of a previously developed energy based function called Rollover Prevention Energy Reserve （RPER）. The RPER function is defined as the difference between the energy needed to bring the vehicle to its tip-over position and the vehicle rotational kinetic energy which can be transferred into gravitational potential thergy to lift the vehicle. According to this definition, the value of the RPER function drops below zero before a vehicle reaches its tip-over position in a rollover case, but always remains positive in a non-rollover case. The algo- rithm developed to calculate RPER is presented in the paper. The RPER function has been validated using experimental results obtained from full-scale vehicle testing performed by the University of Missouri-Co- lumbia. Six light trucks, vans, and utility vehicles, as well as two passenger cars, were extensively tesied in a variety of handling and rollover maneuvers. Different roadside geometries, including transitions from pavement onto soil and into a curb, were used. The validation plots present the RPER functions for both rollover and non-rollover cases.