Mastering Unexpected Situations Safely. Chassis & Safety Vehicle Dynamics

Transcription

1 Mastering Unexpected Situations Safely Chassis & Safety Vehicle Dynamics

2 Benefits and Challenges of using SystemC Models for Pre-Silicon Software Development in the Automotive Industry Division Chassis & Safety

3 Agenda Continentals Business Unit VED Why do we model what in SystemC Simulation and Safety Creating abstract simulation models Conclusion 3

4 Continental Corporation Five Strong Divisions Chassis & Safety Powertrain Interior Reifen ContiTech Vehicle Dynamics Hydraulic Brake Systems Passive Safety & Sensorics Advanced Driver Assistance Systems (ADAS) Engine Systems Transmission Hybrid Electric Vehicle Sensors & Actuators Fuel & Exhaust Management Instrumentation & Driver HMI Infotainment & Connectivity Intelligent Transportation Systems Body & Security Commercial Vehicles & Aftermarket Pkw-Reifen Erstausrüstung Pkw-Reifen Ersatzgeschäft, EMEA Pkw-Reifen Ersatzgeschäft, The Americas Pkw-Reifen Ersatzgeschäft, APAC Air Spring Systems Benecke-Kaliko Group Compounding Technology Conveyor Belt Group Elastomer Coatings Fluid Technology Nutzfahrzeugreifen Power Transmission Group Zweiradreifen Vibration Control 4

5 The Basics If a car assists you or drives you automatically, it has to sense its environment and vehicle s current state... plan its actions......act using the car s actuators and control systems. 5

6 Chassis & Safety Division Business Units Vehicle Dynamics Hydraulic Brake Systems Passive Safety & Sensorics Advanced Driver Assistance Systems Hydraulic Electronic Control Units (HECU) ABS ESC Software functions Traction Control Adaptive cruise control Regenerative brake system Active front steering Hill start assist Hydraulic brake assist Trailer stability assist Chassis electronics Suspension systems Calipers Drum brakes Brake hoses Boosters Tandem master cylinders Electric parking brakes Pedal modules Brake pressure regulators Washer systems Integrated vehicle safety development, safety testing & validation Airbag control units / safety (domain) control units Crash sensors Inertial measurement units Chassis and driver intention sensors Battery and energy monitoring sensors Electronic components (1st tier customer) Wheel, engine and transmission speed sensors Accelerator Force Feedback Pedal (AFFP ) Functions Adaptive cruise control Emergency brake assist Lane departure warning Lane keeping support Blind spot detection Traffic sign assist Intelligent head lamp control Rear cross traffic alert Surround View Sensors Radar Camera Lidar V2X systems 6

7 Business Unit VED Automotive Safety Integrity Level A malfunction of VED products can lead to situations that are with a high probability (E4) uncontrollable (C3) and Life-threatening (S3) Our products thus have to comply with ASIL D. 7

8 Reaching ASIL D High level safety goal: Ensure correctness of timing, order and result Achieved by a proprietary combination of redundancy, error-correcting codes, monitors in software and hardware 8

9 Agenda Continentals Business Unit VED Why do we model what in SystemC Simulation and Safety Creating abstract simulation models Conclusion 9

10 Components of a HECU Motor Valve block Electronic Control Unit Microcontroller Mixed-Signal IC (PCU) 10

11 What do we model for which purpose MCU standalone OS and driver development MCU + PCU communication interface MCU Abstraction MCU + PCU + simple model of selected ECU components ECU Abstraction PCU standalone Test case development: SystemC model for VirtualAte Source: System-level concept validation: Verilog-AMS 11

12 Why do we use SystemC models Reduce Time-to-market by front-loading software development SystemC is standard for high level MCU simulations Tool suites with software analysis features are available Debugger support with similar look and feel as on silicon Identical software image as on silicon Acceptable simulation speed 12

13 Latest MCU (Quasar3) Key features 3x2 Cores in Lockstep Operation 250 MHz Custom-specific failsafe architecture (ASIL-D) 8 MB Program Memory and 1.5 MB SRAM both with ECC 2x Flexray 1x PSI5 1x Ethernet 2 different custom-specific communication interfaces Motor control peripheral set 3x CAN 3x SPI 2x LIN 13

14 Success Stories Beta release of drivers and OS for Quasar3 completely developed on simulator only final tests on silicon Two out of three milestones in the development of the MCU abstraction layer were reached before silicon availability 14

15 Agenda Continentals Business Unit VED Why do we model what in SystemC Simulation and Safety Creating abstract simulation models Conclusion 15

16 Requirements from SW Developer Point of View Software must run on the simulator as on silicon Same exceptions and interrupts need to be triggered Any systematic software bug needs to be detected No software straps are allowed 16

17 ASIL D and Simulation A simulation model will never show wrong behavior. Do I have to model the safety measures implemented in hardware? Which timing accuracy is sufficient for the intended use cases? 17

18 Modeling Safety Measures To meet ASIL D target our hardware requires the software to regularly test the hardware safety measures. Not modeled Software detects hardware error and leaves correct execution path. Hardware Safety Measures Major negative impact on simulation time Detailed model Emulation Preferred trade-off 18

19 Timing Accuracy At the first glance software development at OS level and higher should only require loosely timing. However, it needs to be ensured that the timing requirements of the safety measures are met. Practice has shown that already a wrongly introduced branch delay slot can be a risk for meeting the timing requirements. 19

20 Agenda Continentals Business Unit VED Why do we model what in SystemC Simulation and Safety Creating abstract simulation models Conclusion 20

21 Good and Bad Abstraction of Behavior Often unimplemented functionality is sold as abstraction In fact this usually means the functionality was missed or didn t fit in the schedule Frequently causes unacceptable limitations Small impact on simulator performance Real abstraction requires careful planning of the best way to implement all modules Use available abstraction techniques as e.g. TLM Emulate functionality if applicable 21

22 Pin level abstraction TLM also allows an efficient modeling of communication interfaces Drawbacks Device pins are usually multiplexed Compatibility of interfaces from different suppliers / tools Some use cases require pin level accuracy We need a standard for modeling pin behavior 22

23 Agenda Continentals Business Unit VED Why do we model what in SystemC Simulation and Safety Creating abstract simulation models Conclusion 23

24 Conclusion High safety requirements in the automotive industry require also special attention in model creation Safety measures need to be implemented Abstraction is important for reduction of modeling effort and runtime. But needs to be applied wisely Taken care of the above using SystemC models for software development is feasible and saving development time. 24

25 Thank you for your attention! ASIC solutions for Vehicle Dynamics 25

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