Rotary Position Error Detection Using Reference Device

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Solution Overview

Problem

Current methods for determining rotational position errors in rotary devices are impractical and costly, particularly for smaller devices, as they require extensive calibration time and are sensitive to temperature changes, making it difficult to accurately detect short-period errors.

Innovation Solution

A method using a reference rotary device with a lower error rate to determine rotational position errors by varying the positions of parts relative to each other, allowing for precise measurement of changes without significant external rotation, thereby simplifying the error detection process and reducing calibration time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional calibration methods are used to determine rotational position errors, then measurement precision is improved, but loss of time increases and device complexity increases

Engineering Contradiction:
Improverotational position error detection accuracyVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

A reference rotary device with known, lower error characteristics is introduced as an intermediary standard. The test rotary device is coupled to this reference device, and their relative positions are measured. This intermediary reference system enables accurate error determination without requiring extensive calibration time, as the reference device provides a stable baseline for comparison.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces complex mechanical calibration procedures with a measurement-based approach using optical or electromagnetic position detection systems. Instead of physical alignment and mechanical adjustment, the system uses non-contact measurement of relative positions between the test device and reference device, significantly reducing calibration time while maintaining precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If conventional calibration methods are used to determine rotational position errors, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improverotational position error detection accuracyVSAvoidcalibration system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The reference rotary device serves as a simplified intermediary that provides known reference positions. By coupling the test device to this simple reference standard and measuring their relative positions, the system achieves high measurement precision without requiring complex calibration equipment or procedures.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system creates a simplified measurement model by copying the essential functional relationship between the test device and a reference device. Instead of using complex absolute calibration methods, it measures the relative position relationship, which can be mathematically processed to determine errors without requiring complex physical reference standards.

Inventive Principle:
Principle #26Copying

3Manufacturing precision

If high accuracy rotational position determination systems are used, then manufacturing precision is improved, but cost increases disproportionately

Engineering Contradiction:
Improvepositioning accuracyVSAvoidcost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Instead of manufacturing extremely precise mechanical components for the rotary device itself, the patent substitutes mechanical precision with measurement and calculation. Standard components are used, and their errors are determined through the calibration method using the reference device, then compensated through mathematical correction, achieving high positioning accuracy without high manufacturing costs.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the approach from improving physical manufacturing parameters to improving measurement and computational parameters. By using software-based error compensation and mathematical models to correct for mechanical imperfections, the system achieves high positioning accuracy while using standard, low-cost mechanical components.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If extensive calibration is performed to detect short-period errors, then measurement precision is improved, but loss of time increases

Engineering Contradiction:
Improveshort-period error detectionVSAvoiddetection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The calibration method uses periodic rotation of the rotary device through specific angle ranges, measuring relative positions at multiple discrete points during each period. This periodic measurement approach efficiently captures short-period errors (high-frequency spatial variations) without requiring continuous, time-consuming measurement, as the periodic sampling captures the essential error characteristics.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2943742B1Method and arrangement for determining errors in a rotation position determination system
Publication Date: 2019.07.10 CARL ZEISS INDUSTRIELLE MESSTECHNIKE GMBH
  • EP2943742B1 patent drawingFigure 1
  • EP2943742B1 patent drawingFigure 2
  • EP2943742B1 patent drawingFigure 3

AI summary

Method for determining one or more errors in a rotation position determination system which measures rotation positions of parts of a rotary apparatus (201), wherein a first part (206) and a second part (205) of the rotary apparatus (201) can rotate relative to one another about a rotation axis (D) of the rotary apparatus (201), and the method comprises the following steps: determining a first rotation position of the rotary apparatus (201) with two parts (206, 205) which can rotate relative to one another, determining a first rotation position of a reference rotary apparatus (60) with two parts (61, 62) which can rotate relative to one another, wherein one of the two parts is a third part (61) which is coupled to the second part (205) of the rotary apparatus (201) in a rotationally fixed manner in relation to the rotation axis, and the other part of the two parts is a fourth part (62) which can rotate relative to the third part (61) about a rotation axis of the reference rotary apparatus (R), varying the rotation position of the rotary apparatus (201) in relation to a second rotation position of the rotary apparatus, determining the second rotation position of the rotary apparatus with the rotation position determination system, varying the rotation position of the reference rotary apparatus (60) in relation to a second rotation position of the reference rotary apparatus, determining a resulting rotation position of the first part (206) and of the fourth part (62) relative to one another, said rotation position being changed by virtue of the variation of the rotation positions, determining the rotation position errors of the rotation position determination position from the changed resulting rotation position of the first part (206) and of the fourth part (62) relative to one another, and/or, as an alternative or in addition to the preceding step, varying the rotation position of the rotary apparatus (201) to a second rotation position of the rotary apparatus and varying the rotation position of the reference rotary apparatus (60) to a second rotation position of the reference rotary apparatus (60), with the result that the resulting rotation position of the first part (206) and of the fourth part (62) is not changed, determining the second rotation position of the rotary apparatus (201), and determining the rotation position errors of the rotation position determination system from the rotation positions of the rotary apparatus (201) or the change in the rotation position of the rotary apparatus, and from the rotation positions of the reference rotary apparatus (60) or the change in the rotation position of the reference rotary apparatus.