1. Plant Modeling for Powertrain Control Design Modelica Automotive Workshop Dearborn, MI November 19, 2002 Dr. Larry Michaels GM Powertrain Controls Engineering

2. Challenges in PT Control Design Control System Design starts late Rush to develop algorithm and write code Minimum opportunity to influence hardware Sensors & actuators may already be determined Cost is always a major factor

3. Model-Based PT Control Design Process HWIL tests (Simucar) Calibration Procedures Control System Conceptual Design Software Engineering Testing & Calibration Concept Software System Engineering Analysis Control System Design Algorithm Models Plant Models Diagnostic models Other Deliverables Calibration Methods Test Scenarios Test Calibrations RPC to validate concept Use models to understand algorithm Validate S/W vs. algo. model Software-in-the-loop tests Control Strategy Enhancements Control System Architecture Design Implementation Issues Elaborated algo model Refined PT models Sensor/Actuator models Diagnostics Calibration Procedure Cost models Robustness Controller H/W Engineering Sensor/Actuator Design Powertrain Design PT Plant Models Existing Algorithm Models New Ideas SSTS CTS CTR ADD

4. Control Algorithm Design Process Build Plant Model Analyze and Choose Control Theory Build Plant Control Design Model Calculate Control Algorithm Build Algorithm Model

5. Types of Models Plant - physical system that is a major PT element of interest in a control problem, e.g., engine, transmission, EGR subsystem. It typically includes actuators, sensors, controller circuitry, wiring and environment Plant Model - physics-based or behavioral math model built to understand the problem and represent the dynamics of the system being controlled Plant Control Design Model - simplified plant model used to develop control algorithm via Control Theory, usually linearized model, possibly created from experimental data (System Identification) Algorithm Model - executable representation of an algorithm - equations, data flow diagram, state charts

6. Plant Modeling Issues Plant models may take long to develop Many different models needed –Problem dependent –Fidelity and complexity No standard plant model architecture Need to validate model vs. hardware Desire to reuse models Different tools being used Sensors, actuators, signal delivery system important

7. Controller Hardware and Software ActuatorsSensors Powertrain Engine and Transmission Platform Interface InstrumentationService Tools Assembly Plant Powertrain Control System Block Diagram

8. Input Circuits and HWIO Compute Engine Output Circuits and HWIO On/Off High Side Pulse Width Modulated On/Off Low Side Operating System Application SW HWIO SW Math Library Crank Sensor Throttle Position Coolant Temp O2 Sensor Force Motor Injectors Ignition signals Fuel Pump ECM or TCM Controller Hardware & Software A/D Converter Pulse Counter Frequency measure

9. Plant Modeling Strategies Specific model for problem-at-hand One-size-fits-all model Reconfigurable models for levels of complexity Causal vs. a-causal models –Data flow diagrams –Topological models

10. Plant Modeling Tool Requirements Co-simulation with other tools –detailed engine & transmission models –algorithm models –sensor & actuator models –calibration tools Capable of real-time simulation for HIL Support for various levels of fidelity –e.g., model order reduction Modular structure Easily validated and correlated

11. Plant Modeling Tool Requirements Compatible with CM and version control tools Support for libraries Parametric configuration facilities Enterprise support –documentation, readability, portability Supports software-in-the-loop Scripting capability Web interface