聊聊BMW的ACC功能和實現結構1
我最近在收集一些測試ACC(自適應巡航)和FSRA(全速度範圍自適應巡航)的測試結果,因為實際車上使用有變遷,所以先需要拿2~3家的產品歷史變遷和解決方案來探究一下,以便於討論,因為有BMW的University關於產品的說明比較全,所以從這裡開始。
這裡根據不同的車型平台換代時間,根據其發布給經銷商的介紹資料可以發現,自適應巡航功能(ACC)它大概有過這麼幾個階段:
2002t第一代ACC 1st Gen Active Cruise Control (ACC)
2006t第二代ACC 2nd Gen Active Cruise Control ACC
2007t外購的 t(DCC) Dynamic cruise control (cruise control with brake intervention)tttttttttt
2008t第三代ACC tIntegrated Chassis Management DCC ACC Stop and Gotttttttttt
2012t第四代ACC Active Cruise Control with Stop & Go function (Camera and Radar Sensors)tt
2013t低成本的基於視覺的ACCt Active Cruise Control with Stop & Go Function (Camera Sensors Only)tttttttttt
就關鍵的一些指標,根據裡面摘了出來,等後面我們解析
運行參數(速度範圍、速度範圍內的加速和減速範圍)
靜止物體響應
ISO 15622:2002&2010 Transport information and control systems Adaptive Cruise Control Systems Performance requirements and test procedures
ISO 22178:2009 Intelligent transport systems Low speed following (LSF) systems Performance requirements and test procedures
ISO 22179:2009 Intelligent transport system, Full speed range adaptive cruise control system, performance requirements and test
第一代系統
單雷達(76~77GHz)系統,雷達和ACC模塊是做一起的,通過PT CAN與系統連接。
如減速較小,採用發動機制動來實現 When possible, ACC will decelerate the vehicle by of means of torque or throttle intervention in the DME. If engine drag torque or engine speed reduction is not sufficient for deceleration the ACC control unit requests the DSC hydraulic unit to build up brake pressure for adjustment of the deceleration.
如用了DSC,根據情況核算要不要電剎車燈 If deceleration is triggered by the ACC, the brake lights are activated by the DSC dependent on a specific pressure or deceleration rate.
第二代系統
這裡單獨拎出來一個LDM:
The LDM is a control module that is used for drivetrain and brake coordination purposes ,plus provides significant improvement with regard to automatic cruise control (ACC or DCC) with a general control function capability ranging from requesting acceleration to requesting braking (integrated function).
這裡演算法方面做得更複雜,也有冗餘的功能,從前代前方的放到了後方,整個安裝位置也好了不少。
單個77G雷達固有情況就是如此,這是忽略靜止物體的原因:
The radar waves received cannot distinguish between animals, vehicles and traffic signs.
Traffic signs and parked vehicles standing next to the vehicles lane could incorrectly be assigned to the lane.
In order to prevent incorrect reactions, stationary objects and traffic in the other direction is ignored in the distance control.
外購系統,這是博世的,這個有些奇怪,單獨列出來。
第三代系統
從單雷達系統改進成為一長距+2短距雷達,這裡BMW也將上面的LDM(縱向)改為了 Integrated Chassis Management,這個控制器實現了系統功能物理存在上的整合。
有了兩側的兩個短距雷達,其實對於前方靜止物體的檢測和辨認,就可以實現了,此處在說明內沒有明確的說法,進一步證實需要通過BMW發表的學術論文內的結果和後續內容進行確認。第四代系統、低成本系統我明日整理,這裡引入了視覺系統,也是ADAS系統獨立分離的開始。
小結:大概理了一下整個脈絡,再根據測試結果來對比以上的假定。
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