Model optimization refers to improving a Simulink model to achieve:
| Goal | Description |
|---|---|
| Faster simulation | Reduce execution time of the model |
| Reduced memory usage | Efficient use of system resources |
| Efficient code generation | Generate optimized embedded code |
| Real-time capability | Ensure model runs within time constraints |
Optimization may involve:
- reducing unnecessary blocks
- optimizing data types
- simplifying algorithms
- improving sample time design
Automotive Example:
Optimizing a motor control model to meet a 1 ms control loop execution time.
Slow simulations may be caused by:
| Reason | Impact |
|---|---|
| Complex plant models | High computational load |
| Unnecessary logging | Increased memory and processing time |
| Large solver step sizes | Reduced accuracy and inefficiency |
| Inefficient block structures | Poor execution performance |
Automotive Example:
Vehicle dynamics model slowing ADAS simulations.
Solver optimization ensures selecting the correct solver type and step size for better performance.
| Solver Type | Usage |
|---|---|
| Fixed-step solver | Used for real-time and embedded systems |
| Variable-step solver | Used for detailed analysis and simulation accuracy |
Automotive Example:
Real-time ECU control loop simulation.
Methods to reduce model complexity include:
- simplifying mathematical expressions
- removing redundant blocks
- modularizing subsystems
Automotive Example:
Simplifying tire model for faster ABS simulations.
Logging too many signals increases memory usage and slows simulations.
| Optimization Method | Benefit |
|---|---|
| Log only required signals | Reduces memory usage |
| Use decimation | Logs data at intervals instead of every step |
| Disable unnecessary scopes | Improves simulation speed |
Automotive Example:
Logging only critical signals in cruise control model.
Block reduction removes unnecessary or redundant blocks during simulation to improve performance.
| Concept | Description |
|---|---|
| Block reduction | Eliminates redundant blocks |
| Example | Two gain blocks merged into one |
Automotive Example:
Simplifying control signal calculations.
Signal storage reuse allows the same memory location to be reused for different signals during simulation.
| Benefit | Description |
|---|---|
| Reduced RAM usage | Lowers memory consumption |
| Efficient code | Improves embedded system performance |
Automotive Example:
Optimizing memory usage in motor control software.
Data type optimization reduces memory usage and improves execution speed by choosing appropriate data types.
| Conversion | Benefit |
|---|---|
| double → int16 | Lower memory and faster execution |
Automotive Example:
Using fixed-point signals in motor controllers.
Fixed-point arithmetic reduces computational cost compared to floating-point operations.
| Benefit | Description |
|---|---|
| Faster execution | Less processing overhead |
| Reduced memory usage | Efficient storage |
Automotive Example:
Motor current controller in EV inverter.
Algorithm simplification improves performance by reducing complexity in calculations.
- reducing mathematical complexity
- removing redundant calculations
Automotive Example:
Simplified vehicle dynamics model for ACC.
Lookup tables are used to approximate nonlinear functions efficiently.
| Optimization Technique | Description |
|---|---|
| Reducing table size | Minimizes memory usage |
| Interpolation methods | Improves accuracy between points |
Automotive Example:
Engine torque maps.
Model partitioning divides large models into smaller, manageable subsystems.
| Benefit | Description |
|---|---|
| Easier maintenance | Simplifies debugging and updates |
| Improved simulation speed | Enhances execution efficiency |
Automotive Example:
Separating plant model and controller.
Multi-rate optimization assigns different sample times to different subsystems within a model.
| Concept | Description |
|---|---|
| Multi-rate system | Different parts run at different speeds |
| Sample time assignment | Optimizes performance and accuracy |
Automotive Example:
Fast sensor processing loop and slower control loop.
Dead code elimination removes unused or unnecessary blocks and code during optimization.
| Aspect | Description |
|---|---|
| Unused code removal | Eliminates redundant logic |
| Performance improvement | Reduces execution time |
Automotive Example:
Removing unused diagnostic logic.
Dead code elimination removes unused or unnecessary blocks and code during optimization.
| Aspect | Description |
|---|---|
| Unused code removal | Eliminates redundant logic |
| Performance improvement | Reduces execution time |
Automotive Example:
Removing unused diagnostic logic.
Execution order optimization ensures that blocks execute in the correct and efficient sequence.
| Factor | Importance |
|---|---|
| Correct order | Ensures accurate results |
| Efficient sequencing | Improves simulation performance |
Automotive Example:
Sensor signals processed before control algorithm.
Vectorization processes multiple signals simultaneously instead of one at a time.
| Benefit | Description |
|---|---|
| Faster simulation | Parallel signal processing |
| Efficient computation | Reduced loop operations |
Automotive Example:
Processing multiple sensor signals.
Subsystem reuse optimization involves using reusable subsystems to avoid duplication in models.
| Concept | Description |
|---|---|
| Reusable subsystems | Common logic used multiple times |
| Reduced duplication | Simplifies model maintenance |
Automotive Example:
Shared filtering algorithm across sensors.
Memory optimization reduces RAM usage in Simulink models.
| Technique | Description |
|---|---|
| Storage reuse | Reuse memory for multiple signals |
| Fixed-point signals | Reduce data size |
| Reduced logging | Minimize stored simulation data |
Automotive Example:
Low-memory microcontroller running control software.
Simulation profiling identifies blocks that consume the most execution time during simulation.
| Purpose | Description |
|---|---|
| Performance analysis | Detect slow parts of the model |
| Optimization support | Helps target improvements |
Automotive Example:
Complex plant model slowing simulation.
Signal propagation ensures correct data types and dimensions automatically flow through the model.
| Aspect | Benefit |
|---|---|
| Automatic propagation | Reduces manual configuration |
| Consistency | Avoids mismatch errors |
Automotive Example:
Avoiding unnecessary conversion blocks.
Parallel simulation distributes computations across multiple CPU cores to improve performance.
| Feature | Benefit |
|---|---|
| Multi-core processing | Faster simulation execution |
| Parallel runs | Handles multiple scenarios efficiently |
Automotive Example:
ADAS scenario testing with many simulations.
Code generation optimization improves the efficiency of automatically generated code.
| Aspect | Improvement |
|---|---|
| Execution speed | Faster runtime performance |
| Memory usage | Reduced resource consumption |
| Maintainability | Cleaner and structured code |
Automotive Example:
Generating optimized ECU software.
Model references allow parts of a model to be reused and compiled independently.
| Feature | Benefit |
|---|---|
| Independent compilation | Faster build times |
| Reusability | Reduces duplication |
Automotive Example:
Large ADAS models with reusable modules.
Parameter tuning adjusts model parameters without modifying the model structure.
| Aspect | Description |
|---|---|
| Parameter adjustment | Changes values for better performance |
| No structural change | Model design remains intact |
Automotive Example:
Engine torque map calibration.
Parameter tuning adjusts model parameters without modifying the model structure.
| Aspect | Description |
|---|---|
| Parameter adjustment | Changes values for better performance |
| No structural change | Model design remains intact |
Automotive Example:
Engine torque map calibration.
Model reduction simplifies complex dynamic models while preserving essential behavior.
| Purpose | Benefit |
|---|---|
| Simplification | Reduces model complexity |
| Performance | Faster simulation and analysis |
Automotive Example:
Reduced vehicle dynamics model for control design.
State reduction decreases the number of states in dynamic models to simplify computation.
| Aspect | Benefit |
|---|---|
| Fewer states | Reduced computational complexity |
| Simplified model | Improved simulation speed |
Automotive Example:
Simplified battery model.
Hardware-aware optimization considers system limitations while designing the model.
| Constraint | Description |
|---|---|
| CPU speed | Processing capability of the hardware |
| Memory | Available RAM for execution |
| I/O constraints | Input/output limitations |
Automotive Example:
Model running on ARM-based ECU.
Multi-core optimization distributes simulation tasks across multiple processor cores.
| Feature | Benefit |
|---|---|
| Parallel execution | Faster processing |
| Task distribution | Efficient resource utilization |
Automotive Example:
Running multiple AD