今天，無論是卡車運(yùn)營(yíng)商還是商用車供應(yīng)商，都在努力提升車輛的安全性，他們一方面正在推動(dòng)高級(jí)駕駛輔助系統(tǒng)（ADAS）的標(biāo)準(zhǔn)化，另一方面則在探索車對(duì)車（V2V）通信技術(shù)的應(yīng)用潛能。盡管V2V通信擁有眾多好處，但該技術(shù)能否普及開來依然是個(gè)未知數(shù)。
全球規(guī)模最大的幾家汽車管理公司的高管是汽車安全的積極倡導(dǎo)者。比如在近期由沃爾沃（Volvo）卡車與聯(lián)邦快遞（FedEx）共同舉行的V2V技術(shù)演示會(huì)上，F(xiàn)edEx 的CEO John Smith就反復(fù)強(qiáng)調(diào)要提升車輛安全性。而他的同事則具體闡述了公司將為車隊(duì)全面安裝安全系統(tǒng)的計(jì)劃。
聯(lián)邦快遞通信主管MicheleEhrhart女士表示：“在今年年底，我們將為公司的所有車輛配上碰撞緩解、側(cè)翻穩(wěn)定性控制以及車道偏離預(yù)警功能。并且，除了最陳舊的車輛外，我們其余的所有車輛都安裝了自適應(yīng)巡航控制系統(tǒng)（ACC）系統(tǒng)。”
卡車制造商們也進(jìn)而紛紛表示，買家們都愿意為安裝汽車安全系統(tǒng)而支付更多的費(fèi)用。人身安全是無價(jià)的，而保護(hù)車輛和貨物的經(jīng)濟(jì)回報(bào)是可以估量的。
戴姆勒（Daimler）卡車部門北美福萊納卡車（Freightliner Trucks）分部戰(zhàn)略總經(jīng)理 Kary Schaefer 表示：“由于安全系統(tǒng)能夠減少交通事故，并提高車輛的運(yùn)行時(shí)間，因此車輛安全性的提升能夠大幅提高車輛駕駛過程中的經(jīng)濟(jì)性。需要指出的是，主動(dòng)安全系統(tǒng)與車輛推進(jìn)系統(tǒng)及網(wǎng)聯(lián)系統(tǒng)，并稱為汽車行業(yè)的三大投資領(lǐng)域。”
在卡車供應(yīng)商與運(yùn)營(yíng)商的共同努力下，ADAS系統(tǒng)的配置率有所上升。除此之外，研究者們也開始探究起V2V通信技術(shù)的潛在優(yōu)勢(shì)。汽車行業(yè)目前采用的V2V通信技術(shù)大多基于標(biāo)準(zhǔn)版5.9 GHz頻段專用短程通信技術(shù)（DSRC），用于車輛與車輛以及車輛與路邊信號(hào)裝置的“交流”。值得一提的是，越來越多的公司開始測(cè)試V2V通信技術(shù)應(yīng)用于車輛編隊(duì)行駛的好處。由于編隊(duì)中的車輛能夠互相告知制動(dòng)時(shí)間，因此行車安全性得到了極大提升。此外，V2V技術(shù)的應(yīng)用還能夠縮短車距，幫助整個(gè)車隊(duì)節(jié)約10%的油耗。
ZF公司ADAS系統(tǒng)、車輛自動(dòng)化與商用車技術(shù)研發(fā)部門主管Dan Williams 先生表示：“V2V通信技術(shù)將被首次應(yīng)用于車輛編隊(duì)。而車輛與基礎(chǔ)設(shè)施通信（V2I）技術(shù)的應(yīng)用，能夠幫助車輛在有限的區(qū)域環(huán)境里互相傳遞較為有價(jià)值、且獲取成本不高的信息。”
V2V技術(shù)的應(yīng)用可以有效縮短安全車距，并確保整個(gè)卡車編隊(duì)做到同時(shí)減速。此外，沃爾沃還將V2V通信與自適應(yīng)巡航控制（ACC）系統(tǒng)相結(jié)合，提供了更高的冗余，以確保當(dāng)編隊(duì)頭車放緩速度時(shí)，其它車輛也相應(yīng)立刻放緩速度。
Volvo卡車北美分部產(chǎn)品規(guī)劃副總裁KeithBrandis先生表示：“我們?cè)跇?biāo)準(zhǔn)ACC系統(tǒng)的基礎(chǔ)上加上了V2V通信技術(shù)。這樣，當(dāng)卡車編隊(duì)頭車減速行駛或剎車時(shí)，后續(xù)車輛就能夠利用協(xié)作式ACC系統(tǒng)的DSRC技術(shù)獲取頭車的行駛信息。”
雖然研究人員預(yù)測(cè)V2V通信技術(shù)能夠?yàn)檐囮?duì)運(yùn)營(yíng)商帶來巨額利潤(rùn)，但該技術(shù)的應(yīng)用前景卻受到了質(zhì)疑。具體而言，如果采用編隊(duì)控制系統(tǒng)對(duì)車隊(duì)進(jìn)行控制，那么即使較小規(guī)模的車隊(duì)也能夠獲取一定的運(yùn)營(yíng)利潤(rùn)；如果車隊(duì)規(guī)模較大，就能獲得更大的利潤(rùn)。但在車隊(duì)規(guī)模較小的情況下，額外支付費(fèi)用再添置車輛網(wǎng)聯(lián)技術(shù)就顯得沒有必要。
Williams先生表示：“在這樣一個(gè)混合環(huán)境中，采用V2V通信技術(shù)有時(shí)候能夠幫助我們獲取到有用信息，有時(shí)候卻不能。如果獲取的信息不可靠，那么司機(jī)在做出安全決策時(shí)也就不會(huì)參考這一信息了。”
如今，美國(guó)國(guó)家公路交通安全管理局（NHTSA）遲遲沒有推出有關(guān)強(qiáng)制新車安裝V2V通信設(shè)備的規(guī)定，這進(jìn)一步引發(fā)了人們的猜測(cè)。而蜂窩通信技術(shù)的提倡者們則進(jìn)一步進(jìn)行宣傳，稱5G通信技術(shù)能夠提供足夠的帶寬，給汽車行業(yè)帶來很多好處。
以蜂窩通信技術(shù)為基礎(chǔ)的V2V技術(shù)簡(jiǎn)稱為C-V2V技術(shù)。由于采用了未來幾年內(nèi)有望普及的蜂窩調(diào)制解調(diào)器，該技術(shù)可以省下原先的DSRC鏈接技術(shù)的成本，因此已經(jīng)引起了一些汽車制造商們的興趣。由于汽車或卡車的C-V2V技術(shù)配置率均較低，因此一些汽車公司開始考慮出售5.9-GHz頻段DSRC技術(shù)，不過這一想法遭到了大多數(shù)DSRC技術(shù)支持者的反對(duì)。
Brandis先生表示：“我們正在與美國(guó)聯(lián)邦通信委員會(huì)（FCC）合作共同保護(hù)我們的無線頻段。如果我們獲得的帶寬變窄，那么我們發(fā)出的數(shù)據(jù)量也會(huì)有所減少。由于汽車在未來發(fā)送的數(shù)據(jù)量將會(huì)越來越多，因此這一問題事關(guān)汽車未來發(fā)展。”
如果將來通信基礎(chǔ)設(shè)施能夠做到處理大量的數(shù)據(jù)，那么我們距離實(shí)現(xiàn)所有車輛的自動(dòng)化也就不遠(yuǎn)了。具體來說，無人駕駛汽車在接收到與路況及天氣狀況相關(guān)的數(shù)據(jù)后，能夠有效提升行駛安全。車與車之間能共享路邊行人的信息，以及實(shí)時(shí)交通流量信息。V2V通信技術(shù)所獲取的數(shù)據(jù)，通常比車載傳感器所獲取的數(shù)據(jù)涉及面更廣。因此，隨著自動(dòng)駕駛卡車的不斷普及，提高環(huán)境數(shù)據(jù)的數(shù)量與置信度變得至關(guān)重要。
Williams繼續(xù)解釋說：“傳感范圍的大幅提升有助于車輛更好地發(fā)現(xiàn)周圍的交通安全隱患，使橫向與縱向的控制更好地結(jié)合起來。而這些自動(dòng)駕駛功能的實(shí)現(xiàn)，將提升商用車的安全性與效率，并進(jìn)而提升汽車的自動(dòng)化程度。第一批自動(dòng)駕駛車輛將用于導(dǎo)航難度相對(duì)較低的任務(wù)中，如在偏遠(yuǎn)地區(qū)的公路上將礦物從礦井運(yùn)輸至火車站，或在特定高速公路上保持同車道行駛。”
Truck owners and commercial-vehicle suppliers are ramping up their safety efforts, making more advanced driver-assistance systems (ADAS) standard while looking at the potential benefits of vehicle-to-vehicle (V2V) communications. Though V2V can bring many benefits, widespread usage remains shrouded with questions.
Support for improved safety comes from some of the top executives of the largest vehicle fleets. FedEx CEO John Smith repeatedly commented on the need for improved safety during a recent Volvo Trucks-FedEx V2V demonstration. Associates detailed the push to fully equip the FedEx fleet with safety systems.
“By the end of the year, we will have collision mitigation, rollover stability control and lane-departure warnings on all our vehicles,” said FedEx communications director Michele Ehrhart. “We already have adaptive cruise control on all but the oldest vehicles.”
Truck makers are moving in lockstep, noting that it’s easy for buyers to justify the cost of safety systems. Safeguarding human lives is priceless, but protecting vehicles and cargo has a definable financial payback.
“There’s a very strong business case for improving safety,” said Kary Schaefer, general manager of strategy for Daimler Trucks North America’s Freightliner Trucks. “Every accident that safety systems prevent provides more uptime for the fleet. Active safety is one of three major areas of investment for the industry, along with propulsion and connectivity.”
As suppliers and owners move to equip more vehicles with ADAS, researchers are also exploring the potential benefits of V2V. The industry has standardized 5.9 GHz dedicated short-range communications (DSRC) to let vehicles talk to each other and communicate with roadside beacons. Many companies are testing V2V’s benefits for platooned convoys. When vehicles can tell each other when they’re braking, safety can be improved. Tightening distances between trucks can bring fuel savings up to 10%.
“The first use of V2V communication will be platooning,” said Dan Williams, director of ADAS and autonomy, commercial vehicle technologies, at ZF. “Vehicle-to-infrastructure communication could allow more cost-effective information in a restricted area environment.”
Safely shortening following distances means ensuring that trucks slow down synchronously. Volvo provides redundancy by closely linking adaptive cruise control (ACC) with V2V communications. That helps ensure that all vehicles immediately react when the lead vehicle slows.
“We’re using our standard ACC and adding a layer on top, using V2V,” said Keith Brandis, vice president for product planning at Volvo Trucks North America. “Cooperative ACC uses DSRC to let trailing vehicles know immediately when the lead truck is slowing or braking.”
Researchers feel V2V brings major financial benefits, but its usage remains in question. Platooning brings benefits even if the operating fleets are small. Greater benefits occur when more trucks can communicate, bringing broader safety improvements. It can be difficult to justify connectivity costs when only a few vehicles can talk to each other.
“In a mixed environment where sometimes this information might be available, sometimes not, it can become a source of potentially useful information, but if it is unreliable you may not want to base safety decisions on this data source,” Williams said.
The National Traffic Highway Safety Administration's (NHTSA) tardiness in mandating a rollout date has created questions around adoption. Cellular promoters say that 5G connections provide enough bandwidth to provide many of the benefits.
Called C-V2V, it is gaining some interest from automakers who feel they can eliminate the cost of a DSRC link by using cellular modems that are likely to be on most cars in a few years. Given the lack of usage in cars and trucks, some groups have discussed selling some of the 5.9-GHz DSRC spectrum. That’s not palatable for most DSRC proponents.
“We’re working with the FCC to protect our wireless spectrum,” Brandis said. “If we get narrower bandwidth, it will restrict the amount of data we can send. That’s important for the future, when even more data will be sent.”
Having a communications infrastructure capable of handling lots of data is viewed as an important element in the drive to automate all driving. Data on road and weather conditions can help autonomous vehicles navigate safely. Vehicles could also share information about pedestrians near roadways, as well as providing real-time traffic info. V2V input is often viewed as sensor information that extends farther than on-board sensors. Increasing the volume and confidence levels of environmental data will be important as autonomous trucks move from limited applications to mainstream driving.
“Further out, we will use more sensing to identify safety issues all around the vehicle, and combine longitudinal and lateral control,” Williams said. “These associated functions will help to improve safety and efficiency of commercial vehicles, and lead to increasing levels of automation. The first automated vehicles will appear in duty cycles that are relatively easy to navigate, such as hauling from a mine pit to a railhead on a remote road, or maintaining a lane on a limited access highway.”
Author: Terry Costlow
Source: SAE Truck & Off-highway Engineering Magazine
各種ZF傳感器所獲取的數(shù)據(jù)能夠服務(wù)于車輛的傳動(dòng)系統(tǒng)與制動(dòng)系統(tǒng)，從而提高車輛的安全性。（圖片來源：ZF公司）
編隊(duì)行駛可以帶來很多好處，但是V2V認(rèn)證的規(guī)則仍然不明朗。
