First: Autonomous Industry Background

Since 2012, as Tesla had developed rapidly in autonomous driving, a slash tendence on ADAS and ADS system developmeny spreading worldwide. Many OEMs and Tier1 suppliers had devoted themselves eagerly to ADAS from 2017 based on BEV vehicles, afraid of left behind with Tesla Model S elevating production and selling.

Figure01: ADAS

Second: Safety status present worldwide

However, functional safety in ISO 26262 cannot address fully in the human beings foreseeable misuse, function design limitations accompanying detail use cases. Under this circumstances, ISO groups had derived out Safety Of The Intended Functionality as CD 21448 ISO for future, present only Level0~Level2 can be covered.

I have seen some OEMs and training companies had show how their concept for functional safety and SOTIF, however at present they are not so in high maturity and complete enough for further developments, and which is why I wrote out some passages regarding this issue.

This page will take Lane Keep Assistance and Lane Change Assistance this two Level 2 ADAS system as example to derive out item definition example for reference.

Third: LKA&LCA item definition in OEM side

(1) OEM function Architecture(not real project in any OEM, just brainstorm)

Figure02 Functional Architecture

We have the following related parts will be relative with LKA&LCA

Figure03

(2) Physical properties around each functional component

P-01:

①V2X,

②4G technologies using as state of art, the min{TTI}=1ms, following is the 4G-LTE photos:

Figure04

P-02: Dot-Matrix Infrared Camera, set type RL-1006P as example,

①night vision<120m,

②monitoring_angle=(5~60)deg,

③IP65,

④24h monitoring and scanning,

⑤(-20~50)degC,

⑥Lifetime>7000h

P-03: set type B-70,

①monitoring_angle=(0~105)deg,

②32 lightings once, 16 objects simultaneously

③max_detection_distance=70m if human reflection>30%

④max_detection_distance=35m if reflection ratio >10%

⑤min_delay_time=(400~500)ms

⑥Auto-filtering regularly motion objects

⑦Fixation style: horizonal or vertically

⑧(-20~50)degC,

P-04：77GHz MMVR,

①monitoring_angle=(-20~20)deg,

②shall be positioned in 2.5m

③Positioning in Front or Side, 24GHz[100m] often in the rear

⑤min_delay_time=(150~200)ms

⑥can monitor against fog, smoke, dust, but invalid in heavy rain

⑦Fixation style: horizonal or vertically

⑧(-40~85)degC at least

P-05: GPS+INS

①Longitude error: 9m

②Latitude error: 8m

③Velocity random varies: 0.1m/(s*h^0.5)

④Potential treatment delay time: 1.005s-->150ms

⑤Velocity accuracy: 0.01m/s

Reference: http://www.doc88.com/p-6107677208932.html

Following is the main sensors allocated in the vehicle, there are 2 LIDARs, 4 MMWRs, 2 Cameras:

Figure05:

(3) Cyberphysical attack interface

Red points symbolize potential cyberphysical attack interface.

Figure06:

Fourth: ADAS related important attribute

(1) LKA & LCA is LEVEL2 ADAS system.

As from SAE J3016, sustained lateral and longitudinal vehicle motion control shall be system, but OEDR(including steering+brake) shall be performed by driver, so that the DDTA shall be fallback from system to driver, and ODD is on limited use cases.

So that in HARA steps, the OEM shall derive out many use cases to perform functional safety+SOTIF analysis, then to come to more things.

Figure07:

Fifth: item definition{following things not real project in any OEM, just predictions}

(1) functional safety considerations:

① consider the vehicle only sold in CHINA, so only Chinese legislation GBT 34590+SOTIF+CNAP+else CHINA shall be discussed

②Lane keep assistance will performed when vehicle is in straight way, including highway.

operation mode: vehicle is operating in (40~100)km/h, driver hands on steering wheel, foots on brake

operation state: vehicle is BEV, with all potential weather and road conditions in CHINA,

Lane keep assistance can keep vehicle in the middle of two parallel lanes. If vehicle had sensed lane not as straight in 100meters, then lane keep assistance will have stopped, also send warning to driver for fallback.

LKA functions can working continuously to stop, with 5ms for DTTI lane and distance identification. As usual, LKA can keep working for 8 years, estimating for using it in 16 times a day. If it is needs repaired, it can be done within 5h in 4S store when in 1 year usage, 12h in 4S store when in 3 year usage.

Figure08:

③Lane change assistance will perform when driver want to change the road line in the nearby, no matter if the lane is straight or not.

Figure09:

one potential situation is double lane change, at which vehicle facing with multiple lanes to judge the circles.

Figure10:

The assumption is that LCA also in CHINA, obey GBT34590+CD 21448 ISO as guidance, also CNAP and other Chinese Legislations.

operation mode: in (30~80)km/h, driver hands on steering wheel, foots on brake

operation state: vehicle is BEV, with all potential weather and road conditions in CHINA,

Lane change assistance can warning nearby vehicles and change the lane in the available situations. When changing finished, LCA will inform driver the information and start on to fallback. When in double lane changing, it requires more time to judge and actuate.

LKA functions can working continuously to stop, with 5ms for DTTI lane and distance identification. As usual, LKA can keep working for 8 years, estimating for using it in 16 times a day. If it is needs repaired, it can be done within 5h in 4S store when in 1 year usage, 12h in 4S store when in 3 year usage.

④LCA and LKA will share same items in the vehicle level, which in same color in the Figure03.

(2) SOTIF considerations:

①Use cases of LKA and LCA:

There are too many use cases for LKA and LCA, we only forecast following two critical and corner cases analysis:

Figure11:

(3) Cybersecurity considerations:

In Figure11 use cases, cyber attackers will attack the vehicle from Figure06 potentially.

Basically above context shall be included in the real project as example and all data or contexts is not from real project from any OEM, or sources, it is only brainstorming to perform the methodologies.

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Much thanks!