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Modeling Car Periphery Supervision (CPS) System. Robert Bosch GmbH case study for AMETIST project. Tomas Krilavi čius ¹ & Biniam Gebremichael². ¹ - University of Twente, ² - University of Nijmegen. Outline. Sources Car Periphery Supervision (CPS) Informal description General model
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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
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 SystemsSteffen 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 SupervisionStefan KOWALEWSKI, M. RITTEL, Robert Bosch GmbH
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 • 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
CPS: General model HYBRID STOCHASTIC TIMED Sensor ECU W O R L D Sensor CAR Tasks running on OSEK Sensor • Hybrid • Environment • Sensors • Measurement control (ECU) • Stochastic • ECU – tasks running on OSEK • Car • Airbag control • Belt Tensioner • HMI • Etc
CPS Model HYBRID TIMED Sensor ECU W O R L D Measu rement Control Sensor Tasks running on OSEK Sensor • Step-wise modeling • First step - timed • Sensors • Measurement Control • Second step - hybrid • World • Sensors • Measurement Control • On every step – input from a stochastic model
CPS: Timed model • Problems • Behavior with given parameters • Safe limits for the different parameters • Behavior of the different configurations (different number of sensors) • 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
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 • Modes • CVMode – delivers the radial velocity of the object passing the gate • DMode – delivers a one-dimensional list of objects (radial velocity, radial distance, etc)
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 • Modes • CVMode – delivers the radial velocity of the object passing the gate • DMode – delivers a one-dimensional list of objects (radial velocity, radial distance, etc)
CPS: Plans for a hybrid model X • Hybrid automaton based model • Problems • Minimal and maximal speeds handled with given parameters • Handling of several dangerous objects v Y
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
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 (?)
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?