Robust Modelling Using Bi-Lateral Delay Lines for High Speed Simulation of Complex Systems
Petter Krus · KTH Publication Database DiVA (KTH Royal Institute of Technology) · 2011
A very effective method for modelling and simulation of large complex dynamic systems is represented by distributed modelling using transmission line elements (or bi-lateral delay lines). This method evolves naturally for calculation of pressures when hydraulic pipelines are modelled with distributed parameters, and it can be used to effectively partition the model to use local solvers for the differential equations in each component or subsystem. It is also applicable to other physical systems, such as mechanical, electrical, gas etc. One interesting application for distributed solvers using bi-lateral delay lines is in real time simulation, since they are very robust and usually quite large simulation times steps can be used. Modelling for real-time applications puts special requirements on robustness in the numerical methods used. In real-time applications there is no room for decreasing time step in numerically critical stages. Furthermore, if a system is relaying on a real-time simulation for its functionality, failure in the numerical properties is unacceptable. It is also in many applications possible to simulate the system faster than real time, which means that high fidelity system simulation can be used to plan ahead in control applications, and for simulation based optimisation. Since solvers can be embedded in components or subsystems, it is very straightforward to implement parallel processing using the multi-core processors which now is the standard for desk top computers. There is also an increasing need in many situations to resolve the time scale to finer details, where the effect of wave propagation needs to be modelled.