Position Encoder Signal Calibration for Precision Error Correction

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Solution Overview

Problem

Existing devices for determining position, length, or angle, such as encoders, suffer from inaccuracies due to systematic and random errors, sensor variations, and aging-related changes, which affect the precision of position determination.

Innovation Solution

Incorporating a correction unit that influences measurement signals during a calibration run to generate a correction table or function, compensating for deviations from an ideal curve, and applying this correction during normal operation to improve accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If correction is applied to measurement signals, then position determination precision is improved, but device complexity increases

Engineering Contradiction:
Improveposition determination precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing calibration runs before normal operation to generate correction tables and functions. These corrections are pre-calculated and stored, then applied during normal measurement operations. This approach improves precision without adding complex real-time correction mechanisms, as the complex calibration work is done beforehand.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes parameters by introducing correction tables and correction functions that modify measurement signals based on pre-determined calibration data. Instead of fundamentally redesigning the measurement system, it adjusts the signal parameters using correction factors derived from calibration runs, thereby improving precision with minimal structural changes.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If calibration run is performed to generate correction data, then measurement accuracy is improved, but loss of time occurs

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The calibration process is performed as a preliminary action before normal operation begins. The correction tables and functions are generated once during calibration runs, and then reused during normal measurement operations. This concentrates the time investment in a single setup phase rather than requiring continuous calibration time during operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a copy of the ideal measurement behavior through correction tables and functions derived from calibration runs. Instead of repeatedly performing full calibration procedures, the system uses these copied correction data to maintain accuracy during normal operation, significantly reducing the time loss associated with recalibration.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP4636361B1Device and method for determining position, length or angle
Publication Date: 2026.03.18 SICK AG
  • EP4636361B1 patent drawingFigure 1
  • EP4636361B1 patent drawingFigure 2A
  • EP4636361B1 patent drawingFigure 2B~2C

AI summary

The present invention relates to a device, in particular for determining the position, length, or angle between two parts that are movable relative to one another. The claimed device is characterized by a correction unit designed to influence the course of measurement signals used to determine the relative position between the two parts. For this purpose, a calibration signal is generated from output signals of corresponding sensors in a calibration run. The course of this calibration signal is compared with a predetermined reference course. From this, a correction table and/or a correction function is generated. Based on this correction table and/or function, the course of the subsequently generated at least one measurement signal is then influenced in order to correct errors and/or deviations indicated by corresponding deviations.