Non-Iterative Co-Simulation Error Correction via Feedback

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Solution Overview

Problem

Non-iterative co-simulation methods face inaccuracies due to extrapolation of coupling variables, leading to errors in energy analysis between subsystems, which are exacerbated by larger macro step sizes and the limitations of existing numerical solution algorithms.

Innovation Solution

A method that estimates and modifies coupling variables using a correction signal to reduce errors, where the error signal from each macro time step is used to adjust the correction signal for subsequent steps, allowing for adaptive macro step size control without requiring meta-information about the subsystems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If non-iterative coupling strategy is used, then simulation time is reduced and productivity is improved, but accuracy deteriorates due to extrapolation errors

Engineering Contradiction:
Improvesimulation timeVSAvoidaccuracy of coupling variables
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the error signal from each macro time step is used to adjust the correction signal for subsequent steps. The correction system continuously monitors the difference between estimated and actual coupling variables and uses this feedback to minimize extrapolation errors in future predictions, thereby maintaining accuracy while preserving the speed benefits of non-iterative coupling.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically changes the correction signal parameters based on the error signal from previous time steps. By adapting the correction magnitude and timing according to actual simulation results, the method optimizes the balance between computational efficiency and accuracy, reducing extrapolation errors without requiring iterative recalculations.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If larger macro step sizes are used, then productivity is improved, but accuracy deteriorates due to increased extrapolation errors

Engineering Contradiction:
Improvesimulation speedVSAvoidaccuracy of energy analysis
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The feedback mechanism monitors energy transfer accuracy and adjusts correction signals accordingly. When larger macro step sizes are used, the error signal becomes more significant, triggering stronger correction actions that compensate for the increased extrapolation errors, thus maintaining energy analysis accuracy while preserving the productivity benefits of larger time steps.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent combines multiple approaches into a composite coupling method: it integrates non-iterative coupling for speed with a correction system that applies targeted adjustments based on error feedback. This composite approach allows the system to benefit from both large macro step sizes and maintained accuracy, effectively resolving the contradiction between simulation speed and energy analysis precision.

Inventive Principle:
Principle #40Composite materials

3Measurement precision

If iterative coupling approach is used, then accuracy is improved, but productivity deteriorates due to multiple iterations required

Engineering Contradiction:
Improveaccuracy of coupling variablesVSAvoidsimulation time
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies preliminary correction actions based on error feedback from previous time steps. Instead of performing multiple iterative calculations during each macro time step, the method pre-adjusts the coupling variables using correction signals derived from historical error data, achieving high accuracy in a single pass and eliminating the time-consuming iterative process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The method dynamically changes correction parameters based on accumulated error signals, allowing the system to adapt to varying system conditions and maintain accuracy without requiring repeated iterations. This parameter adaptation enables the system to achieve iterative-level precision with non-iterative computational efficiency.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If extrapolation of coupling variables is performed, then productivity is improved, but harmful factors increase due to energy transfer errors

Engineering Contradiction:
Improvesimulation efficiencyVSAvoidenergy transfer errors
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The feedback mechanism specifically targets energy transfer errors by monitoring the difference between estimated and actual energy exchanges. The correction system uses this energy-specific feedback to adjust coupling variables in a way that minimizes spurious energy creation or destruction, thereby maintaining simulation efficiency while eliminating the harmful energy transfer errors generated by naive extrapolation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent converts the harmful energy transfer errors into beneficial information by using the error signal to drive correction actions. The extrapolation errors, rather than being discarded as unwanted side effects, are systematically analyzed and transformed into corrective adjustments that improve the accuracy of energy transfer calculations while preserving the computational efficiency of the non-iterative approach.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP2442248B1Coupling method for non-iterative co-simulation
Publication Date: 2016.12.14 KOMPETENZZENTRUM DAS VIRTUELLE FAHRZEUG FORSCHUNGS GMBH
  • EP2442248B1 patent drawingFigure 1
  • EP2442248B1 patent drawingFigure 2
  • EP2442248B1 patent drawingFigure 3~4

AI summary

The method involves determining the introduced error signal during co-simulation for modifying subsequent extrapolations (13) to compensate for the disturbance influence. The simulation result for current macro-step is generated based on estimated resultant signal. An error signal over current macro-step is determined, by comparison of estimated signal and resulting simulation result. An independent claim is included for method for reducing influence of exploration of error produced by non-iterative co-simulation.