Modeling Car Periphery
Supervision (CPS) System
Robert Bosch GmbH case study for
AMETIST project
Tomas Krilavičius¹ & Biniam Gebremichael²
¹ - University of Twente, ² - University of Nijmegen
Outline
Sources
Car Periphery Supervision (CPS)
Informal description
General model
Model of Car Periphery Supervision system
CPS model
Timed model
Sensor
Measurement Control
Plans for a hybrid model
Results
Further plans & questions
Tomas Krilavičius & Biniam Gebremichael
Modeling Car Periphery Supervision System 2
Sources
Pre-crash Sensing – Functional Evolution based
on Short Range Radar Sensor Platform
Rainer MORITZ, Robert Bosch GmbH
A Case Study in Applying a Product Line
Approach for Car Periphery Supervision Systems
Steffen THIEL, Stefan FERBER, Thomas Fischer,
Andreas HEIN, Michael SCHLICK, Robert Bosch GmbH
OSEK/VDX, Time-Triggered Operating System
OSEK group
Real-Time Service Allocation for Car Periphery
Supervision
Stefan KOWALEWSKI, M. RITTEL, Robert Bosch GmbH
Tomas Krilavičius & Biniam Gebremichael
Modeling Car Periphery Supervision System 3
CPS: Informal description
CPS obtains and makes
available for other
systems information about
environment of a car. This
information may be used
for:
Parking assistance
Pre-crash detection
Blind spot supervision
Lane change assistance
Stop & go
Etc
Based on Short Range
Radar (SRR) technology
Tomas Krilavičius & Biniam Gebremichael
The CPS considered in
this case study
Reduced to one sensor
group (1..6 sensors)
Only the front sensors
and corresponding
controllers
Application: pre-crash
detection, parking
assistance, stop & go
Modeling Car Periphery Supervision System 4
CPS: General model
Hybrid
Environment
Sensors
Measurement
control (ECU)
Stochastic
ECU – tasks
running on OSEK
Car
Airbag control
Belt Tensioner
HMI
Etc
HYBRID
TIMED
STOCHASTIC
Sensor
W
Sensor
ECU
O
Tasks
R
running
L
on
D
Tomas Krilavičius & Biniam Gebremichael
C
A
R
OSEK
Sensor
Modeling Car Periphery Supervision System 5
CPS Model
Step-wise modeling
First step - timed
Sensors
Measurement Control
Second step - hybrid
World
Sensors
Measurement Control
On every step –
input from a
stochastic model
Tomas Krilavičius & Biniam Gebremichael
HYBRID
W
O
TIMED
Sensor
Sensor
Measu
ECU
rement Tasks
R
running
L
Control
D
Sensor
on
OSEK
Modeling Car Periphery Supervision System 6
CPS: Timed model
UPPAAL (based on timed
automaton) model
Sensors – send and receive
radar signals and make basic
data processing
Measurement control - sends
the commands DScan
(reqDScan) and
CVMeasurement (CVScan) to
all sensors and receives
responses
Tomas Krilavičius & Biniam Gebremichael
Problems
Behavior with given
parameters
Safe limits for the
different parameters
Behavior of the different
configurations (different
number of sensors)
Modeling Car Periphery Supervision System 7
CPS: Sensor
Sensor – sends and receives
radar signals and makes basic
data processing
Failure mode – a sensor is
broken, but it can be repaired,
if it gets command Repair
Tomas Krilavičius & Biniam Gebremichael
Modes
CVMode – delivers the radial
velocity of the object
passing the gate
DMode – delivers a onedimensional list of objects
(radial velocity, radial
distance, etc)
Modeling Car Periphery Supervision System 8
CPS: Measurement Control
Measurement control –
sends the commands DScan
(reqDScan) and
CVMeasurement (CVScan) to all
sensors and receives responses
Failure mode – a sensor is
broken, but it can be repaired
by sending Repair command
Tomas Krilavičius & Biniam Gebremichael
Modes
CVMode – delivers the radial
velocity of the object
passing the gate
DMode – delivers a onedimensional list of objects
(radial velocity, radial
distance, etc)
Modeling Car Periphery Supervision System 9
CPS: Plans for a hybrid model
Hybrid automaton based
model
Problems
Minimal and maximal
speeds handled with given
parameters
Handling of several
dangerous objects
Tomas Krilavičius & Biniam Gebremichael
X
v
Y
Modeling Car Periphery Supervision System 10
Results
A timed model (draft version) in UPPAAL
Some results from analysis of systems:
If a speed of an approaching object is <13km/h (3,6m/s),
CPS looses it, because timeout occurs in CVMode processing
If a speed of an approaching object is >270km/h (75m/s), a
deadline of 30ms (section 2.3.3.4 Situation Analysis)
combined with 15ms and 7m (section 2.3.3.1 Measurement
Control) can not be satisfied
Tomas Krilavičius & Biniam Gebremichael
Modeling Car Periphery Supervision System 11
Further plans
Iterative extension of model
Development and analysis of the timed model
Exchange of the results between the stochastic and the timed
models
Development and analysis of the hybrid model
Exchange of the results between the models
Stochastic-hybrid model (?)
Tomas Krilavičius & Biniam Gebremichael
Modeling Car Periphery Supervision System 12
Questions
More communication with Robert Bosch GmbH
Properties of sensors – maximal and minimal velocities,
distances
Behavior of the system, when several objects are in the
“dangerous area”
Timeouts for Sensor in DSMode(2) mode
Timeouts for Measurement Control (TCVM, TDScan)
Are these questions are interesting?
Comments?
Tomas Krilavičius & Biniam Gebremichael
Modeling Car Periphery Supervision System 13
That’s all...