car-mechatronics introduction to advanced driver ... summer school 2011 - advanced driver assistance...

HAWtech Summer School 2011 - Advanced Driver Assistance Systems (ADAS)

Prof. Dr. T. Trautmann 01.08.2011- 1 -

CAR-Mechatronics

Introduction to Advanced Driver Assistance Systems



CAR-Mechatronics

Topics

Vehicle Stability Control (ESP)

Intersection Assistance



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Vehicle Stability Control - Necessity

ESP`99

Typischer Unfallablauf: Seitenkollision

Unfallbeteiligter: geringe Verletzungen

Unfallverursacher: tödliche Verletzungen

Unfallverursacher ist am Ende des Überholvorganges ins Schleuderngeraten

Unfallbeteiligter

Unfallstelle

Bild 13b

Loss of control after overtaking



CAR-Mechatronics

Vehicle Stability Control – Detection of unstable situation (1)

A

B

C

β

BewegungsrichtungFahrzeugschwerpunkt

Fahrzeuglängs-

achse

v y vF

v x

yaw-ratesteering-angle

slip-angle(should be < 5° !!!)



CAR-Mechatronics

Vehicle Stability Control – Detection of unstable situation (2)

1 – without ESP2 – with ESP

Loss of control for vehicle 1Slip-angle can not be measured, thereforethe yaw-rate will be used for the detectionof unstable situation.



CAR-Mechatronics

Vehicle Stability Control - Control

Controller(PID)+

-

Calculationof Expected

value

Actuator-Gateway ABS / ASR

vehi

cleMwheel,iMzSignal-

configuration

Yaw-rate-sensor

S

I

,vx,ay,..

Structure of ESP-Controller (simplified):

Two ways of calculation:Can be measured

Limitation of maximum friction



CAR-Mechatronics

Vehicle Stability Control – Calculation of yaw-rate

0 5 10 15 20 25 30 35 40 45 500

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Fahrzeuggeschwindigkeit / m/s

Gie

rge

schw

indi

gke

it / 1

/s

Maximal mögliche Querbeschleunigung(Reibwertbegrenzung,Im Beispiel ay = 0.9g)

= 30°

= 60°

= 90°

ay = 0.3g

ay = 0.6g

ay = 1.0g

vchar at maximum yaw-rate



CAR-Mechatronics

Vehicle Stability Control - Elements

Drehzahlfühler

Lenkradwinkel-sensor Gierraten-

sensor

Hydraulikblock

Hydraulikaggregatmit Steuergerät

Steuergerät



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Vehicle Stability Control - Results



CAR-Mechatronics

Intersection Assistance - Necessity

Failure to yield the right of way is frequently involved. A key underlying cause is the complexity of the traffic situation and hence the substantial increase in the burden on the driver's attention at intersections.

Traffic signal and right-

of-way assistanceTurning and entering

assistance

Approximately 60 % of accidents in city traffic and 28% of all accidents occur at intersections.

Here, driver assistance systems capable of reducing the driver burden and providing timely hazard warnings offer a considerable potential for preventing accidents.



CAR-Mechatronics

Intersection Assistance - Example

Strehlener Straße

Fran

klin

stra

ße

source: EUSKA

Number and sortof accidents in year 2005 at an intersection in Dresden nearuniversity

Car-Motorbike

Car-CarCar-bicycle

Drink-driving



CAR-Mechatronics

Intersection Assistance – Basic principle



CAR-Mechatronics

Intersection Assistance – distance measurement



CAR-Mechatronics

Intersection Assistance – Complexity of Situation

ca. 5s ca. 58 s



CAR-Mechatronics

Intersection Assistance – High-Resolution Scanner

Laserscanner

Fahrerkamera Außenkamera

Zentrale Messtechnik

Laserscanner

Fahrerkamera Außenkamera

Zentrale Messtechnik

ID 1

ID 3 ID

4ID 5 ID

6

ID 13

ID 7

ID 9ID

10ID 11

ID 15

ID 2

ID 8

ID 14

ID 12

ID 3

ID 16

ID 18

ID 17

ID 19

ID 20ID

21

ID 1

ID 3 ID

4ID 5 ID

6

ID 13

ID 7

ID 9ID

10ID 11

ID 15

ID 2

ID 8

ID 14

ID 12

ID 3

ID 16

ID 18

ID 17

ID 19

ID 20ID

21

1 measurement:

80ms240° field of view0,25° resolution2 objects per channel4 layers

>>> 7680 points @ 80ms>>> 96000 points @ 1s !!!



CAR-Mechatronics

Intersection Assistance – Detection of objects (1)

1

2

3

4

5

6

Segmentation of raw data

1. Search of edgesMerging of points to lines orrectangles depending on distance and straigtness

2. Calculation of center of gravityUse of geometrical data and signal intensity



CAR-Mechatronics

Intersection Assistance – Detection of objects (2)

1. Segmentation

FusObj_new_Pos(40 x 8)

4.6.

SegDat(40 x 4)1.SensDat

(91 x 4)

(Dis0, Amp0) (Dis1, Amp1)

(x, y, Amp, Anz)

FusObj(40 x 8)

5.

SensDat_rest(40 x 4)

2.

new_Obj(40 x 8)3.

2. Assoziation of objects and segments

3. Find new objects4. Fusion and ordering of objects

5. Return of current objects and survive objects

6. Prediction

Parameters



CAR-Mechatronics

Intersection Assistance – Detection limits (1)

Rmin1 = B/2 / (tan(/2)) - v·(0.06s·Z)

Rmin2 = B/2 / (tan()) - v·(0.06s·Z) B

v

Rmin1

D = v*0.06s*Z



CAR-Mechatronics

Intersection Assistance – Detection limits (2)

Maximum possible speed for oncoming vehicles

0

10

20

30

40

50

60

70

80

90

100

110

120

130

0,8 1 1,2 1,4 1,6 1,8 2 2,2 2,4 2,6 2,8 3 3,2 3,4 3,6 3,8

Winkelauflösung [°]

max

. Ges

chw

indi

gkei

t [km

/h] LKW

PKW

Angle [°]

Vel

ocity

v [k

m/h

]

Detection time: 300 ms (5 cycles)

max. deceleration (truck, b = 2.55m): 5m/s²max. deceleration (passenger car, b = 1.8m): 8m/s²



CAR-Mechatronics

Intersection Assistance – Test Design in Citroën C6

Radar RadarScanner

Display

Driver information is possible by a Display or the built-in Head-Up-Display

Active intervention is possible due to external control of the electromechanical parking brake(prevention of driveaway)



CAR-Mechatronics

Intersection Assistance – Test Design in Citroën C6

P



CAR-Mechatronics

Intersection Assistance – Accident example (1)

source: EUSKA

source: GIDAS



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two traffic signs

meanwhile traffic light installed



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16,58m

Detection Distance:

Rmin = 21.8 m

Braking Distances:

s_br1 = 8.0 ms_br2 = 44.0 m

5,25m

Resolution Laserscanner: 3.6°

Driver-information too late – accident not avoidable

!



CAR-Mechatronics


36,16m

11,45m

Driver-information on time - accident avoidable

!

Resolution Laserscanner: 1.8°

Detection Distance:

Rmin = 48.6 m

Braking Distances:

s_br1 = 8.0 ms_br2 = 44.0 m



CAR-Mechatronics

Intersection Assistance – Further Development

Detailed Analysis of Drivers behaviour Position/Movement of drivers head use of physiological markers like heart beat, skin conductivity,…

100 150 200 250100

120

140

160

180

200

[m]

[m]

globale Objektposition

sx =1.82 m

sy =9.07 m

s =9.25 munbekannt kleinunbekannt gross

Objekt klein

Fahrzeug

GebaeudeRand

-100 -50 0 50 100-20

0

20

40

60

80

100

[m]

[m]

Fahrzeugumfeld

12

234

389

6325

4326

61

56

27

6

1

29 14

39

35

560 580 600 620 6400

20

40

60

80

100

[cycle]

[%]

Pedalbetätigung

Bremse

Gas

560 580 600 620 6400

20

40

60

80

100

[cycle][k

m/h

]

Geschwindigkeit

v Obj =24.05 km/hv car =0.00 km/h

500 550 600 650

-100

-50

0

50

100

[cycle]

[Blic

kric

htun

g]

Blickwinkel



CAR-Mechatronics

Intersection Assistance – Practical exercise

Calculation of object velocity use of position detected by laser-scaner calculation/filtering of object velocity comparision with on-board velocity-sensor

car-mechatronics introduction to advanced driver ... summer school 2011 - advanced driver assistance...

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