Transcript A FCW, CIB and DBS benefit estimation method developed in ACAT program Hirofumi Aoki, Masami Aga, Yoshiki Miichi, Yoshiaki Matsuo, and Shin Tanaka Toyota Motor.

A FCW, CIB and DBS
benefit estimation method
developed in ACAT program
Hirofumi Aoki, Masami Aga, Yoshiki Miichi,
Yoshiaki Matsuo, and Shin Tanaka
Toyota Motor Corporation
Developing Systems to
Reduce/Mitigate Rear-end Collisions
Subaru
Toyota
Honda
Mercedes
Volvo
Control Sequence
Ordinary
Driving
Collision
FCW
Speed
DBS (Brake Assist)
CIB (Automated braking)
Time
The objective in ACAT
FCW, DBS and CIB
specification
System
benefit
Drivers reaction to Benefit
Ordinary
Driving
Collision
FCW
Speed
DBS (Brake Assist)
CIB (Automated braking)
FCW
+ DBS
CIB
Time
Drivers reaction to Benefit
Ordinary
Driving
Collision
FCW
Speed
DBS (Brake Assist)
CIB (Automated braking)
FCW
+ DBS
CIB
Time
Each benefit significantly depends on
“how drivers react before collisions”.
So…
Driver behavior investigation
using the Driving Simulator
Driving Simulator Test Example
Driver Reaction Before Collisions
[m/s2]
Maximum
deceleration 10 (31 persons in total)
20 - 30s
40 - 50s
60s -
8
6
4
2
0
0.0
1.0
2.0
[s]
Period from warning to braking onset
Rear-end Reconstruction Concept
How are rear-end collisions
happening?
Traffic accidents are happening
incidentally
Rear-end Collision Modeling
Rear-end collisions are happening by a combination of
Various brake trigger timings
* Various response delays
* Various braking patterns
Brake trigger timing
Coasting
Braking
How was the hypothesis verified
EDR Data Analysis
Number of cases
(Total 70 cases)
30
20
10
28
20
11
6
4
1
0
None -1s -2s -3s -4s -5s
Braking onset before a crash
Speed reduction (mph)
CDR system connected
to a crashed vehicle
0
- 20
- 40
- 60
None -1s -2s -3s -4s -5s
Braking onset before a crash
Source : NHTSA EDR database
ftp://ftp.nhtsa.dot.gov/NASS/EDR_Reports/
EDR
Simulation result
Frequency
[%]
50
0
40
-10
30
-20
20
-30
10
-40
0
-50
None -1s
-2s
-3s
-4s
Braking onset before a crash
-5s None -1s -2s -3s -4s -5s
Speed reduction [mph]
Comparison between EDR
and simulation result
Braking onset before a crash
Simulation result shows similarity to EDR
Rear-end Collision Simulation
Without a System
Danger
is
noticed
later
than
warning
onset
Danger
is
noticed
prior to
warning
onset
A
Coasting
+FCW,DBS & CIB
Braking
With a System
P
B
Q
C
R
D
S
E
T
DBS CIB
Braking
onset
will be
sooner
Warning
System benefit can be estimated by comparing
P v.s. A, Q v.s. B, R v.s. C and so on.
Simulation 1
FCW onset = 1.7 sec SV = 20m/s
DBS onset = 0.8 sec
*Under the Japanese MLIT
guideline in 2003
CIB onset = 0.45 sec
Expected to
push brake pedal
FCW
0
Speed
3.2mph
CIB
4.5mph
6.3mph
5
reduction
FCW
FCW
+DBS +DBS
+CIB
Not expected
to push
brake pedal* *e.g.,
8.1mph
10
(mph)15
FCW
0
Crash
avoidance
ratio
5
10
(%)
15
0.0%
FCW
FCW
+DBS +DBS
+CIB
0.0%
1.0%
CIB
0.0%
sleepy or
fell asleep
Simulation 2
FCW onset = 2.0 sec SV = 20m/s
DBS onset = 1.1 sec
CIB onset = 0.75 sec
Not expected
to push
brake pedal
Expected to
push brake pedal
FCW
0
Speed
5
reduction
9.1 mph
12.3 mph
15.4 mph
(mph)15
FCW
0
5
10
(%)
15
CIB
5.7 mph
10
Crash
avoidance
ratio
FCW
FCW
+DBS +DBS
+CIB
0.0%
FCW
FCW
+DBS +DBS
+CIB
CIB
0.0 %
7.9 %
13.5 %
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