This course is about the simulation of complex technical systems. It covers the range from detailed equations to integration of multiple software for simulation. The course is based around the transmission line modelling (bi-directional delay lines) paradigm for partitioning of models, with application in the Hopsan simulation package, and for co-simulation. However, it also includes more general topics applicable to simulation in general.
Course objective
After the course the participants should:
- Have a broad orientation of simulation methods and tools.
- Be able to use methods and tools for simulation and co-simulation.
- Be able to develop system models.
- Be able to develop component models at an equation level for system simulation.
- Be able to match the level of detail with what is needed for a specific task.
- Use simulation models for optimization.
- Being prepared to use Large Language Models, LLMs for modelling.
Course content
- Introduction and Basic Concepts of System Simulation
- Course overview
- Introduction to the Hopsan simulation package and relation to other simulation tools
- Transmission Line Modelling
- Simulation in the frequency domain
- Frequency dependent friction.
- Hydraulic and Electrical systems.
- The Unit Transmission Line Element
- Numerical Methods
- Accuracy and stability analysis and characteristics of different methods
- Differential Algebraic Equations
- Algebraic solvers, Newton-Raphson
- Variable time step
- Event free systems
- Equation Based Modelling
- Object Oriented Modelling
- Modelica
- Connectivity
- Co-simulation (e.g., Matlab/Simulink)
- Simulation with FMI
- Simulators connecting to e.g. UNREAL Engine
- Component modelling
- Hopsan built-in editor and Mathematica/Compgen
- Hydraulic components
- Electrical components
- Gas/pneumatic components
- Mechanical components
- Euler-Lagrange equation
- Friction, multi-body systems, 2D-mechanics
- Discrete event systems
- Using LLM for modelling and simulation
- Simulation based optimization.
- Optimization methods
- Objective function formulation
- Parametrization
- Optimizer performance
- Macro functionality
Literature
- Lecture Notes
- Selected research publications
- Dissertations from IEI/Flumes.
Examination
The course is examined through a project that is defined together with the examiner which is then executed and then presented at the end of the course.
Instructors 2026
Petter Krus petter.krus@liu.se
Robert Braun robert.braun@liu.se
Schedule
Date |
Topic |
| 2026 Oct 13 13-17 CET |
Introduction and Basic Concepts of System Simulation (PK, RB) – Simple modelling and simulation using LLM – Transmission line dynamics |
| Oct 21 13-17 CET |
Transmission line dynamics. (PK) – Simulation in the frequency domain – Frequency dependent friction. – Electrical Systems |
| Nov 5 13-17 CET |
Numerical methods (PK, RB) |
| Dec 2 13-17 CET |
Equation based modelling. (RB) |
| Dec 9 13-17 CET |
Co-simulation (RB) |
| Dec 16 13-17 CET |
Component Modelling (PK, RB)
|
| 2027 TBD |
Component Modelling (PK, RB) |
| 2027 TBD |
Simulation based optimization (RB) |
| 2027 TBD |
Examination (PK; RB) |
Download course plan here: Course plan System Modelling and Simulation 2026 (002).