車輛側(cè)翻傾向動(dòng)態(tài)測(cè)試的研究（一）

車輛側(cè)翻傾向動(dòng)態(tài)測(cè)試的研究（一）

為了定量分析車輛的側(cè)翻傾向，必需開發(fā)一變工況下預(yù)測(cè)車輛側(cè)翻可靠的動(dòng)態(tài)測(cè)試方法。本文介紹車輛側(cè)翻穩(wěn)定性方面已經(jīng)開發(fā)的動(dòng)態(tài)測(cè)試的一些成果。開發(fā)車輛側(cè)翻傾向的測(cè)試，必需首先確定車輛側(cè)翻所繞的軸線（側(cè)翻軸）的位置。為此應(yīng)首先進(jìn)行中心軸概念的研究。如本文所述表明，車輛中心軸位置是不可預(yù)測(cè)的，導(dǎo)致三種可能的側(cè)翻軸的分析，要進(jìn)行車輛系統(tǒng)的動(dòng)能和勢(shì)能，和其部件變形造成的結(jié)果以及過去開發(fā)的能量基礎(chǔ)函數(shù)所謂側(cè)翻防止能量?jī)?chǔ)備（RPER）的研究。RPER的定義為車輛到達(dá)側(cè)翻位置所需的能量和車輛回轉(zhuǎn)運(yùn)動(dòng)能量可轉(zhuǎn)換成舉升車輛的重勢(shì)的差值。根據(jù)這種定義，在車輛側(cè)翻情況下，在到達(dá)側(cè)翻位置前，RPER函數(shù)值應(yīng)降至零，通常在非側(cè)翻情況RPER常為正值。本文介紹了開發(fā)的計(jì)算RPER的算式。RPER函數(shù)已經(jīng)被Missouri-Columbia大學(xué)，采用全尺寸6輛輕型貨車，箱式載貨車和輕型箱式越野車輛以及二輛轎車，在不同的控制和側(cè)翻掉縱過程的擴(kuò)展試驗(yàn)獲得的試驗(yàn)結(jié)果證實(shí)。試驗(yàn)時(shí)還采用的路邊幾何狀況，包括路面鋪土到鋪石子的過渡段。本文對(duì)兩側(cè)翻和非側(cè)翻情況繪出RPER的性能曲線。

［Abstraet］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 vehicle 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 algorithm 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-Columbia.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.

側(cè)翻傾向 側(cè)翻防止能量?jī)?chǔ)備 動(dòng)態(tài)測(cè)試 側(cè)翻穩(wěn)定性

（上接第2期）

圖16 石子傾斜路面?zhèn)确抡娼Y(jié)果Fig.16 Curb-tripped rollover simulation results

側(cè)邊和路邊碰撞產(chǎn)生的結(jié)果示于圖19，這些側(cè)邊路邊碰撞是4.5 m／s，5.0 m／s和5.5 m／s下進(jìn)行的，僅在5.5 m／s情況下車輛發(fā)生側(cè)翻，三RPER2函數(shù)和彈性質(zhì)量?jī)A倒角同時(shí)發(fā)生，僅5.5 m／s RPER2成為負(fù)值。

和路邊30°傾斜碰撞的結(jié)果如圖20所示。這些仿真是在初始速度為5.0，5.5和6.0 m／s進(jìn)行的。僅在6.0 m／s車輛發(fā)生側(cè)翻。因此，對(duì)此初始速度在6.0 m／s以下的，RPER2函數(shù)值均保持為正。

所述結(jié)果表明，RPER2函數(shù)可始終如一地精確地確定車輛側(cè)翻，而RPER2同時(shí)還能預(yù)測(cè)車輛側(cè)翻的發(fā)生。對(duì)于側(cè)邊和傾斜沙地碰撞的側(cè)翻最小速度分別是7.0和8.0 m／s。對(duì)于側(cè)邊和傾斜路邊碰撞的側(cè)翻取小速度分別為5.5和6.0 m／s。當(dāng)車輛彈簧質(zhì)量?jī)A倒角達(dá)50°時(shí)，應(yīng)考慮側(cè)翻發(fā)生。

對(duì)于側(cè)邊沙地碰撞RPER2函數(shù)在接近0.45秒傾倒角為28°成為負(fù)值，然而該傾倒角直到0.7秒仍未達(dá)到50°。傾斜沙地碰撞RPER2函數(shù)在接近0.9秒彈簧質(zhì)量?jī)A倒角為38°時(shí)成為負(fù)值，在這樣情況直到1.30秒，傾倒角達(dá)不到50°。

路邊碰撞RPER2函數(shù)幾乎直到0.45秒傾倒角達(dá)28°仍保持為正值，直到0.7秒，彈簧質(zhì)量?jī)A倒不到50°。傾斜路邊碰撞RPER2函數(shù)在接近0.40秒和傾倒角30°成為負(fù)值。然而彈簧質(zhì)量要求0.8秒達(dá)傾倒角50°。

概括和結(jié)論

發(fā)現(xiàn)中心軸概念，對(duì)分析彈簧質(zhì)量運(yùn)動(dòng)，在傾斜的車輛側(cè)翻方面不能提供一合適的軸，而導(dǎo)致三可能側(cè)翻軸的研究。采用該三軸估算用于動(dòng)態(tài)側(cè)翻測(cè)量中勢(shì)能和動(dòng)能項(xiàng)目間能量的改變?；谶@方面分析，第一側(cè)翻軸平行于車輛的X軸，確定其僅對(duì)用于側(cè)翻預(yù)測(cè)函數(shù)是合適的。

兩動(dòng)態(tài)測(cè)量可以估算和預(yù)測(cè)車輛側(cè)翻，側(cè)翻防止能量?jī)?chǔ)備RPER1和RPER2已采用實(shí)驗(yàn)和仿真結(jié)果進(jìn)行開發(fā)和驗(yàn)證。在RPER2數(shù)值方面，實(shí)驗(yàn)數(shù)據(jù)和仿真結(jié)果之間，該驗(yàn)證產(chǎn)生少許差異。這些驗(yàn)證進(jìn)一步表明兩RPER函數(shù)適于在輕度和適度碰撞工況下工作，但在最嚴(yán)重的碰撞工況下，RPER2比RPER1更可靠，因?yàn)镽PER2在預(yù)測(cè)車輛側(cè)翻方面更加穩(wěn)定。因此，RPER2被推薦為廣泛應(yīng)用的側(cè)翻預(yù)測(cè)函數(shù)。

采用上述結(jié)論研究4組仿真方案RPER2函數(shù)的性能，在各組方案中，進(jìn)行個(gè)別仿真時(shí)，僅初始速度有少量增大。從小的傾倒角到完全側(cè)翻，伴隨著合適的RPER2特性，傾倒角逐漸增大。EPER2函數(shù)對(duì)非側(cè)翻開始并保持為正值，而RPER2函數(shù)對(duì)側(cè)翻過程變成并保持為負(fù)值。

盡管本研究?jī)H采用傾斜側(cè)翻駕駛方案，但該RPER概念已成功用操縱誘導(dǎo)側(cè)翻以及［18-19］補(bǔ)充和證實(shí)，在其中采用RPER函數(shù)在靈敏度分析中作為實(shí)物側(cè)翻測(cè)量，目的在于確定不同的車輛和對(duì)車輛側(cè)翻響應(yīng)環(huán)境參數(shù)的影響。用RPER函數(shù)在靈敏度分析已證實(shí)比采用傾倒角或傾倒率作為側(cè)翻測(cè)量更加優(yōu)越。

除它理論上用于預(yù)測(cè)側(cè)翻和確定其嚴(yán)重性外，該RPER概念可完成現(xiàn)行事故防止或在車輛擺脫駕駛員的控制或接近側(cè)翻作為乘客的保持裝置。而且為有助于工程師們和保護(hù)乘客的另一種可能，今后建議它明確列入高速公路車輛系統(tǒng)法規(guī)（IHVS）中。（谷雨譯自SAE paper No.930831）

圖17 側(cè)滑移入沙地Fig.17 Side skid into sand

圖18 傾斜滑入沙地Fig.18 Oblique skid into sand

圖19 側(cè)滑入路邊Fig.19 Side skid into a curb

感謝

感謝美國交通部國家交通安全局（NHTSA）的支持，本文中部分研究描述屬No.DTNH22-89-C-07005有關(guān)評(píng)價(jià)，調(diào)查結(jié)果和建議允許包含本著作中，作者可不必表明出至NHTSA。

圖20 傾斜滑入路邊Fig.20 Oblique skid into a curb

符號(hào)

Nomenelature

回轉(zhuǎn)軸最接近車輛彈簧質(zhì)量中心的點(diǎn)

A

Point on rottional axis closest to vehicle sprung mass center

車輛車輪支持區(qū)周線和通過A點(diǎn)側(cè)翻軸垂直平面交點(diǎn)

B

Intersection point of vehicle wheel support area perimeter and the plane perpendicular to the rollover axis passing through point A

車輛彈簧質(zhì)量中心

C

Vehicle sprung mass center

重力加速度矢量

G

ravitational acceleration vector

車輛彈簧質(zhì)量質(zhì)心慣性矩陣

IC

Vehicle sprung mass centroidal inertia matrix

慣性參考系統(tǒng)

IRS

Inertial Reference System

ms

車輛彈簧質(zhì)量

Vehicle srun mass pg

車輛總質(zhì)量

mt

Vehicle total mass

N

沿側(cè)翻軸法向矢量

Normal vector along rollover axis

非慣性的參考系統(tǒng)

NIRS

Non-Inertial Reference System

彈簧質(zhì)量沿NIRSX軸回轉(zhuǎn)半速

p

Rotational quasi-velocity of sprung mass along x-axis of NIRS

彈簧質(zhì)量沿NIRS Y軸回轉(zhuǎn)半速

q

Rotational quasi-velocity of sprung mass along y-axis of NIRS

RAC

在IRS內(nèi)從點(diǎn)到C點(diǎn)矢量

Vector from point A to point C in IRS

RBC

在IRS內(nèi)從B點(diǎn)到C點(diǎn)矢量

Vector from point B to point C in IRS

彈簧質(zhì)量沿NIRS Z軸回轉(zhuǎn)半速

r

Rotational quasi-velocity of sprung mass along z-axis of NIRS

在NIRS內(nèi)A點(diǎn)到C點(diǎn)矢量

rAC

Vector from point A to point C in NIRS

在NIRS內(nèi)B點(diǎn)到C點(diǎn)矢量

rBC

Vector from point B to point C in NIRS

側(cè)翻防止能量?jī)?chǔ)備

RPER

Rollover Prevention Energy Reserve

回轉(zhuǎn)動(dòng)能

TK

Rotational kinetic energy

轉(zhuǎn)換矩陣

T

Transformation matrix

彈簧質(zhì)量沿NIRS X軸的平移速度

u

Translational velocity of sprung mass along x-axis of NIRS

彈簧質(zhì)量中心在IRS內(nèi)總平移速度

VC

Total translational velocity of sprung mass center in IRS

彈簧質(zhì)量中心沿IRS的X軸速度分量

VXComponent of sprung mass center velocity along X-

axis of IRS

彈簧質(zhì)量中心沿IRS的Y軸速度分量

VY

Component of sprung mass center velocity along Y-axis of IRS

車輛重力勢(shì)能

Vcru

Gravitational potential energy of vehicle

彈簧質(zhì)量沿NIRS的Y軸的平移速度

v

Translational velocity of sprung mass along y-axis of NIRS

車輛彈簧質(zhì)量中心的速度垂直于NIRS內(nèi)側(cè)翻軸

vr

Velocity of vehicle sprung mass center perpendicular to vehicle rollover axis in NIRS

車輛彈簧質(zhì)量中心在NIRS內(nèi)總速度

vs

Total velocity of vehicle sprung mass cen＇er in NIRS

車輛彈簧質(zhì)量中心沿車輛NIRS內(nèi)側(cè)翻軸的速度

vt

Velocity of vehicle sprung mass center along vehicle rollover axis in NIRS

彈簧質(zhì)量沿NIRS的Z軸的平移速度

w

Translational velocity of sprung mass along z-axis of NIRS

沿IRS的X軸任意點(diǎn)的座標(biāo)

X

Coordinate of arbitrary point along X-axis of IRS

XAC

沿NIRS的X軸任意點(diǎn)的座標(biāo)

x

Coordinate of arbitrary point along x-axis of NIRS

沿IRS Y軸任意點(diǎn)的座標(biāo)

Y

Coordinate of arbitrary point along Y-axis of IRS

（下接2014.No.4）

An Investigation Into Dynamie Measures of Vehiele Rollover Propensity

Amdrze G.Nalecz Zhengyu Lu Kemneth L.d＇Entremont
SJTU Mechanical&Power Engineering Institute

Rollover propensity Rollover provention energy reserve（RPER） Dynamic measures Rollover stability

U467.1＋9

A

1006-8244（2014）03-44-05