Control Device Disturbance Detection Using Relational Value Comparison

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Solution Overview

Problem

Existing control devices require high-accuracy simulation models to detect disturbances and abnormalities, which is impractical and inefficient.

Innovation Solution

A control device that compares relational values to detect changes in output values using a low-accuracy model, incorporating a relational value comparator, change amount comparator, and margin calculator to set thresholds for accurate detection without relying on high-accuracy simulation models.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a high-accuracy simulation model is used to detect disturbances and abnormalities, then detection accuracy is improved, but model complexity and parameter setting difficulty increase

Engineering Contradiction:
Improvedisturbance detection accuracyVSAvoidmodel complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts only the necessary input-output relationship from the complex simulation model, creating a simplified model that captures essential behavior without requiring full physical accuracy. This extracted simplified model is sufficient for disturbance detection when combined with relational value comparison.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the approach from using detailed physical parameters to using relational values that represent input-output relationships. By comparing how these relational values change under different conditions, the system achieves accurate disturbance detection without needing high-accuracy physical parameters.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a high-accuracy simulation model is used to detect disturbances and abnormalities, then detection accuracy is improved, but calculation load increases

Engineering Contradiction:
Improvedisturbance detection accuracyVSAvoidsimulation calculation load
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The invention extracts only the essential input-output behavioral characteristics from complex simulation models, creating simplified models that require minimal calculation resources while maintaining sufficient accuracy for disturbance detection through relational value comparison.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses simple, computationally inexpensive models that can be rapidly updated and discarded if needed, replacing the need for continuous use of computationally intensive high-accuracy simulation models while maintaining detection effectiveness.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If model accuracy is reduced to simplify the model, then ease of manufacture and operation improve, but detection accuracy deteriorates

Engineering Contradiction:
Improvemodel production easeVSAvoiddisturbance detection accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The invention introduces relational values as an intermediary between the simplified model and the disturbance detection function. These relational values capture the essential input-output relationships needed for detection, allowing simple models to achieve accurate disturbance detection without requiring high physical accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention transforms the detection approach from relying on accurate physical parameters to relying on changes in relational values. This parameter transformation allows simple models to effectively detect disturbances by monitoring how input-output relationships change, rather than requiring accurate absolute values.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3173891B1Control device, control program, and recording medium
Publication Date: 2019.06.26 OMRON CORP
  • EP3173891B1 patent drawingFigure 1
  • EP3173891B1 patent drawingFigure 2~3
  • EP3173891B1 patent drawingFigure 4~5

AI summary

A characteristic change, disturbance, and an abnormal state are accurately detected with no use of a high-accuracy simulation model. A control device for controlling a control target includes a predictive value calculator that outputs a predictive value of an output value to an input value with respect to a model of the control target, a prediction error calculator that calculates a relational value indicating a relationship between the predictive value and a measured value of output of the control target; and a change detector that compares a first relational value to a second relational value, the first relational value being the relational value in a reference state in which the control target operates normally, the second relational value being the relational value in an operating state in which the control target is operated.