a fcw, cib and dbs benefit estimation method developed in acat program hirofumi aoki, masami aga,...
TRANSCRIPT
A FCW, CIB and DBS benefit estimation method developed in ACAT program
Hirofumi Aoki, Masami Aga, Yoshiki Miichi, Yoshiaki Matsuo, and Shin
TanakaToyota Motor Corporation
Developing Systems to Reduce/Mitigate Rear-end Collisions
Toyota
Honda
Subaru
Mercedes
Volvo
Control Sequence
FCW, DBS and CIB specification
System benefit
The objective in ACAT
Ordinary
DrivingCollisio
n
DBS (Brake Assist)FCW
CIB (Automated braking)
Time
Speed
Drivers reaction to BenefitOrdinar
y Driving
Collision
Time
Speed
FCW + DBS
CIB
DBS (Brake Assist)FCW
CIB (Automated braking)
Drivers reaction to Benefit
So…
Each benefit significantly depends on
“how drivers react before collisions”.
Ordinary
Driving
Time
Speed
Collision
FCW + DBS
CIB
DBS (Brake Assist)FCW
CIB (Automated braking)
Driver behavior investigation using the Driving Simulator
Driving Simulator Test Example
Driver Reaction Before Collisions
Maximumdeceleration
20 - 30s40 - 50s60s -
Period from warning to braking onset
0
2
4
6
8
10
0.0 1.0 2.0
[m/s2]
[s]
(31 persons in total)
Rear-end Reconstruction Concept
How are rear-end collisions
happening?
Traffic accidents are happening incidentally
Rear-end Collision ModelingRear-end collisions are happening by a combination of
Braki
ng
pat
tern
s
* Various braking patterns
Coasting
Various brake trigger timings
Brake trigger timing
* Various response delays
Braking
How was the hypothesis verified
EDR Data Analysis
- 60
- 40
- 20
0
Sp
eed
red
ucti
on
(m
ph
)
3m/s 24m/s 25m/s 2
0
10
20
30
Nu
mb
er
of
cases
None-1s
(Total 70 cases)
20
28
11
41
6
-2s -3s -4s -5s
Braking onset before a crash
None-1s -2s -3s -4s -5s
Braking onset before a crash
Source : NHTSA EDR database
CDR system connected to a crashed vehicle
ftp://ftp.nhtsa.dot.gov/NASS/EDR_Reports/
Comparison between EDR
10
20
30
40
[%]
Fre
qu
en
cy
50
Sp
eed
red
ucti
on
[m
ph
]
0
-30
-20
-10
-40
-50None
-1s
-2s
-3s
-4s
-5s
None-
1s-
2s-
3s-
4s-
5s
and simulation result
0
Simulation result
Braking onset before a crash
Braking onset before a crash
EDR
Simulation result shows similarity to EDR
Rear-end Collision SimulationWithout a System
B
D
A
C
E
CoastingBrakin
g
Braki
ng
pat
tern
s
System benefit can be estimated by comparing P v.s. A, Q v.s. B, R v.s. C and so on.
With a System
Warning
Q
S
P
R
T
DBS CIB Danger is noticed later thanwarning onset
Braking onset
will besooner
Danger is noticed prior towarning onset
+FCW,DBS & CIB
FCW onset
DBS onset
CIB onset
= 1.7 sec= 0.8 sec= 0.45 sec
SV = 20m/s
*e.g., sleepy or fell asleep
Expected to push brake pedal
(%)
Speed reduction
Crash avoidance ratio
0
5
10
15(mph)
FCW FCW +DBS
FCW +DBS +CIB
CIB
Not expected to push brake pedal*
3.2mph
6.3mph8.1mph
4.5mph
0
5
10
15
0.0% 0.0% 1.0% 0.0%
*Under the Japanese MLIT guideline in 2003
Simulation 1
FCW FCW +DBS
FCW +DBS +CIB
CIB
5.7 mph
12.3 mph15.4 mph
9.1 mph
0.0%7.9 %
13.5 %
0.0 %
Simulation 2
FCW onset
DBS onset
CIB onset
= 2.0 sec= 1.1 sec= 0.75 sec
SV = 20m/s
(%)
Speed reduction
Crash avoidance ratio
0
5
10
15(mph)
FCW FCW +DBS
FCW +DBS +CIB
CIB
0
5
10
15
FCW FCW +DBS
FCW +DBS +CIB
CIB
Expected to push brake pedal
Not expected to push brake pedal
Conclusions
An estimation of the benefit of FCW, CIB and DBS was developed.
1. Driver response before collisions was measured in the driving simulator. It was shown that response varied widely from person to person.
2. Rear-end collisions were reconstructed. The result was validated with the EDR data analysis.
3. Estimation method demonstrated the benefit difference by each specification.
Current Study; LDW benefit estimation
End