在自動(dòng)駕駛汽車的設(shè)計(jì)圖上，我們常常會(huì)看到座椅呈傾斜或朝向后方。奧托立夫公司（Autoliv）致力于為未來(lái)的自動(dòng)駕駛汽車營(yíng)造安全乘坐環(huán)境，對(duì)于公司的工程師而言，這些以前看似不可能實(shí)現(xiàn)的座椅布置方式，對(duì)被動(dòng)安全保護(hù)提出了新的挑戰(zhàn)。
這家汽車安全公司的產(chǎn)品研發(fā)副總裁E. Scott Dershem此前在位于密歇根州奧本山的技術(shù)中心接受了《汽車工程》雜志的采訪，他表示：“自動(dòng)駕駛汽車的被動(dòng)安全是一個(gè)難以解決的復(fù)雜問(wèn)題，這也是為什么我們選擇從最基本的場(chǎng)景切入——即坐在稍微傾斜的座椅上的前排乘客遇到正面碰撞。”
安全工程師已經(jīng)認(rèn)識(shí)到，自動(dòng)駕駛汽車的座椅布置方式將有別于傳統(tǒng)汽車。Dershem表示，“我們面臨的難題不是如何達(dá)到某個(gè)自動(dòng)駕駛級(jí)別，而是如何為車內(nèi)靈活布置的座椅提供有效的安全保護(hù)。”
這就是為什么“以座椅為中心”的安全變得至關(guān)重要。Dershem表示，“目前的法律法規(guī)已經(jīng)對(duì)安全帶的掛點(diǎn)位置做出了強(qiáng)制規(guī)定。但是自動(dòng)駕駛汽車的座椅會(huì)發(fā)生旋轉(zhuǎn)和傾斜，因此目前的掛點(diǎn)位置已不再是最佳的選擇。我們可以通過(guò)改變掛點(diǎn)位置的方式來(lái)解決該問(wèn)題，比如前移掛點(diǎn)，讓安全帶不再扣在腹部的位置。”
安全氣囊的封裝通常受到座艙配置的影響。如果自動(dòng)駕駛汽車去除了儀表板或其它傳統(tǒng)的座艙配置，那么座椅將是放置氣囊的最佳位置。
Dershem說(shuō)道，“自2014年起，我們就在開發(fā)一款叫‘LifeCell’的概念產(chǎn)品，這是一款帶有兩個(gè)充氣裝置的簾狀氣囊。”Life Cell安全氣囊啟動(dòng)時(shí)從座椅內(nèi)彈出。完全釋放后，氣囊會(huì)包裹住乘客的頭部和肩部。Dershem表示，“我們已經(jīng)改良了這款產(chǎn)品，此前的第一代氣囊是不會(huì)包住頭部的。”
研究人員和工程師正在探討，當(dāng)座椅的傾斜角度處于所謂的“正常后傾”角度時(shí)，應(yīng)當(dāng)如何保護(hù)乘客的安全。目前計(jì)算機(jī)模擬和碰撞假人測(cè)試結(jié)果表明，此時(shí)乘客的頭部并不在安全氣簾的保護(hù)區(qū)域內(nèi)。
Dershem還談到了乘坐自動(dòng)駕駛汽車可能會(huì)導(dǎo)致的另一個(gè)問(wèn)題，“我們正在討論是否應(yīng)該在座椅傾斜時(shí)抬高座椅。這樣做有兩個(gè)好處：1. 當(dāng)發(fā)生側(cè)面碰撞時(shí)，抬高座椅可以讓氣簾得以包裹住頭部。2. 乘客頭部的位置會(huì)在車輛的腰線以上，并和車窗重新持平，以預(yù)防暈車。”
仿真第一
奧托立夫的被動(dòng)安全系統(tǒng)測(cè)試流程通常從計(jì)算機(jī)仿真測(cè)試開始，然后進(jìn)行靜態(tài)測(cè)試。靜態(tài)測(cè)試的目的是為了檢測(cè)安全氣囊觸發(fā)后測(cè)試假人的狀況。接著是測(cè)試假人受到固定障礙物沖擊的滑車測(cè)試。Dershem表示，“如果我們想要調(diào)整一項(xiàng)不完善的技術(shù)，通常會(huì)需要從源頭開始。”最后一步的測(cè)試將在實(shí)車上進(jìn)行。
據(jù)介紹，奧托立夫的技術(shù)人員可能會(huì)到2020年才開始進(jìn)行假人實(shí)車碰撞測(cè)試。Dershem表示，“一些汽車制造商希望打造自動(dòng)駕駛汽車接送服務(wù)，這些車企很可能會(huì)率先開展實(shí)車測(cè)試。”
當(dāng)碰撞事故發(fā)生時(shí)，被動(dòng)安全系統(tǒng)可以保護(hù)乘客的安全。與此同時(shí)，這些技術(shù)在事故預(yù)防中也發(fā)揮著重要作用。
Dershem表示，“自動(dòng)駕駛汽車會(huì)采取避撞措施，比如快速變道或緊急剎車，以防止和路面物體發(fā)生沖撞。這些物體可能是其它車輛，也可能是行人、騎車者，甚至可能是一頭鹿。試想一下，如果座艙布置得像客廳一樣，沒(méi)有一位乘客系著安全帶，然后車輛突然以1G的減速度剎車，那么車內(nèi)肯定會(huì)怨聲四起。”
Reclined and rotated seating positions are commonly depicted for autonomously driven vehicles. But for the Autoliv engineers tasked with developing occupant safety for tomorrow’s self-driving vehicles, those previously improbable seating positions dictate innovative new passive safety protections.
“Passive safety for autonomous vehicles is a pretty complicated problem to solve, which is why we’re starting out with the simplest scenario: a frontal crash with a front occupant in a partial-recline position,” E. Scott Dershem, Autoliv’s Vice President of Product Development, said in an interview with Automotive Engineering at the safety supplier’s Auburn Hills, Michigan technical center.
Safety engineers know occupants in self-driving vehicles might be seated in unconventional positions. “For us, it’s not really about a particular level of autonomy; it’s more about the level of seating flexibility inside the vehicle,” he said.
That’s why "seat-centric" safety is vital. “There are laws and regulations now as to where seatbelt anchors have to be. But as seats rotate and recline, today’s anchor points aren’t in the optimum location. That issue could be solved with a change in the anchor point, such as moving it further forward to get the seatbelt off the abdomen area,” he offered.
In-cabin features heavily influence the packaging of airbags. But if a self-driving vehicle is without a conventional instrument panel or other traditional cabin fixtures, the seats are the prime packaging locale for airbags.
“We’ve been working on our Life Cell concept since 2014. It’s a curtain airbag with two inflators,” said Dershem. The Life Cell airbag deploys from the seat and when fully deployed essentially envelopes the occupant’s head and shoulders. “The product has evolved. Our first-generation version didn’t go over the occupant’s head,” he said.
Researchers and engineers are looking for ways to address what happens during a so-called ‘normal-recline seating position.’ Computer simulations and testing with crash dummies show that the occupant’s head won’t be within the curtain airbag’s protection zone when seated in the ‘normal recline’ position.
“We’ve been talking about raising the seat up as you recline. That does two things: It gets the head back into the curtain area during a side impact. It also puts the head above the vehicle’s belt line and back into the window area so the occupant doesn’t get motion sickness,” he said, referring to a malady that’s possible when riding in an autonomously-driven vehicle.
Simulation first
Autoliv’s typical testing process for passive safety systems starts with computer simulations. That’s followed by static testing to determine what happens to crash test dummies when airbags deploy and sled crashes with crash-test dummies into fixed barriers. “It’s not uncommon to go back to the beginning if we want to tweak an under-development technology,” he said. The final testing stage involves actual vehicles.
Autoliv technicians likely won’t conduct crash tests with dummies inside physical vehicles before the 2020 timeframe. “Some vehicle manufacturers are looking to do autonomous mobility as a delivery service, so those are likely to be first in-line for actual vehicle testing,” he said.
Passive safety systems offer protection during a vehicle crash, but those same technologies could be vital in instances of accident avoidance.
“There will be evasive maneuvers by autonomously driven vehicles that prompt a quick lane change or emergency braking to avoid a collision with another vehicle, pedestrian, bicyclist, deer, or some other object,” said Dershem. “Imagine if the occupants are in ‘living room’ seating position and the vehicle does 1G braking and no one is belted. It’s going to get ornery inside that vehicle.”
Author: Kami Buchholz
Source: SAE Automotive Engineering Magazine
Autoliv工程師正在設(shè)計(jì)安全氣囊和安全帶系統(tǒng)，用于自動(dòng)駕駛車輛的傾斜和放松座椅位置。(圖片來(lái)源：Autoliv)
Autoliv副總裁Scott Dershaw身旁的碰撞測(cè)試假人（圖片來(lái)源：Autoliv）
這款由Adient設(shè)計(jì)的模塊化座椅框架包含一個(gè)安裝在框架上的安全氣囊和一個(gè)集成的安全帶系統(tǒng)。 Autoliv正在與座椅制造商合作，將其安全氣囊和安全帶系統(tǒng)整合到車輛座椅中。（圖片來(lái)源：Autoliv）
安全氣囊上的油漆痕跡顯示了將測(cè)試假人撞到障礙物的后遺癥。(圖片來(lái)源：Autoliv)