Co-Simulation Interface Prediction for Accurate Parallel Simulation

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Solution Overview

Problem

Co-simulation in mechatronic systems faces challenges due to incompatible platforms and software, leading to reduced accuracy and increased processing time, with existing methods like Gauss-Seidel exchanges and energy conservation struggling to manage numerical artefacts and discontinuities.

Innovation Solution

A method that disaggregates systems into subunits, uses data prediction models to forecast numerical data, and adjusts simulation steps based on error and time-stepping to ensure smooth communication and accurate simulation, employing polynomial functions and Hermite interpolation for continuity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If data exchange frequency is increased to improve accuracy, then simulation accuracy improves, but processing time increases

Engineering Contradiction:
Improvesimulation accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by using data prediction models (polynomial functions, Hermite interpolation) to forecast interface variables before actual data exchange occurs. This allows receiving subsystems to proceed with simulation steps using predicted values, reducing the frequency of actual communications while maintaining accuracy. The prediction models are prepared in advance and continuously updated based on historical data patterns.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces prediction models as intermediary elements between sending and receiving subsystems. These models act as mediators that translate and forecast interface variables, allowing subsystems to operate with predicted values instead of requiring continuous direct communication. This intermediary layer reduces communication overhead while preserving simulation accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If discrete time sampling is used for communication between subunits, then parallel simulation efficiency improves, but numerical artefacts and instabilities occur

Engineering Contradiction:
Improveparallel simulation efficiencyVSAvoidsimulation stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements continuity of useful action by using continuous prediction models (polynomial functions and Hermite interpolation) to generate interface variables between discrete communication events. This creates a continuous approximation of the interface behavior, eliminating the discontinuities that cause numerical instabilities while maintaining the efficiency of discrete parallel simulation architecture.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent applies parameter changes by transforming discrete sampled data into continuous prediction models with adjustable parameters (polynomial coefficients, interpolation points). This allows the system to maintain discrete communication timing while generating continuous variable representations that prevent numerical artefacts and solver restarts.

Inventive Principle:
Principle #35Parameter changes

3Loss of time

If higher time steps are used for data exchanges to improve efficiency, then processing time decreases, but accuracy of global solution deteriorates

Engineering Contradiction:
Improveprocessing timeVSAvoidglobal solution accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent uses preliminary action by pre-computing prediction models based on historical data patterns before larger time steps are taken. This allows the system to skip intermediate communication events while having accurate predictive models ready, maintaining global solution accuracy even with higher time steps between actual data exchanges.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where prediction models are continuously updated and refined based on actual measured data from previous simulation steps. This feedback loop ensures that even with larger time steps, the prediction accuracy is maintained by adapting models to actual system behavior patterns observed during simulation.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4229489B1Co-simulation, computer system
Publication Date: 2024.07.10 SIEMENS IND SOFTWARE NV
  • EP4229489B1 patent drawingFigure 1A
  • EP4229489B1 patent drawingFigure 1B
  • EP4229489B1 patent drawingFigure 2

AI summary

A computer-system (CPS) and a computer-implemented method for numerical modular simulation of a system (SYS), comprising: (a) disaggregating said system (SYS) into at least two subunit (SSY) simulation subsystems (SMN), (b) simulating the respective subunits (SSY) stepwise repeatedly generating subsystem-step-output (MSO) from subsystem-step-input (MSI) during a respective subsystem-time-step (SMP). To improve accuracy and performance said method comprises the additional steps: (c) transmitting subsystem-step-inputs (MSI) to a receiving subsystem (SMR) and simulating this subsystem (SMN) over a delay-time (DLT) before its subsystem-step-outputs (MSO) are generated, (d) receiving connection interface variables (TRD) from a sending subsystem (SMS) comprising at least one of: - numerical data (DTA), - at least parameters of a data-prediction-model (DEM) of said numerical data (DTA), - a data-prediction-model (DEM) assigned to said numerical data (DTA), (e) predicting said numerical data (DTA) by a data-prediction-model (DEM) over said delay-time (DLT) to obtain predicted numerical data (EDT) of said interface variables (TRD) provided by said sending subsystem (SMS), (f) starting the next simulation step of said receiving subsystem (SMR) generating the next subsystem-step-output (MSO) from subsystem-step-input (MSI), wherein said subsystem-step-input (MSI) comprises said predicted numerical data (EDT).