Angle Measuring Device Eccentricity Correction

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Solution Overview

Problem

High-precision angle measuring devices face accuracy issues due to manufacturing tolerances causing eccentricity and wobble errors in large diameter shafts and rotary tables, especially when using absolutely coded code tracks, which existing correction methods cannot address.

Innovation Solution

An angle measuring device with a graduation carrier, at least two scanning units, and a control unit that processes angle values from these units to correct for eccentricity and wobble errors, allowing for improved accuracy by transmitting corrected angle values to subsequent electronics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple scanning units are used to measure不同角度 values for correction, then measurement accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveangle measurement accuracyVSAvoidnumber of scanning units and processing circuitry
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The code track is divided into multiple segments that can be read by different scanning units positioned at different angular locations. Each scanning unit reads a portion of the code track, and the control unit combines these partial readings to determine the complete angular position, thereby improving measurement accuracy without requiring a single complex scanning unit

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control unit acts as an intermediary that receives angle values from multiple scanning units, processes these values to correct for eccentricity and wobble errors, and outputs the corrected angle value. This intermediary processing step enables accuracy improvement while managing the complexity through centralized coordination

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If correction processing is implemented in the angle measuring device, then measurement accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveangle measurement accuracyVSAvoidprocessing unit and correction algorithms
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control unit performs correction processing in advance by calculating correction values based on the angle values from multiple scanning units before outputting the final corrected angle value. This preliminary correction action ensures that accuracy is improved while the complexity is managed through pre-computed correction factors

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from multiple scanning units to detect eccentricity and wobble errors, then feeds this information back to the control unit which calculates appropriate correction values. This feedback mechanism enables continuous accuracy improvement while maintaining manageable device complexity through iterative correction

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2551645B1Method and device for measuring angles
Publication Date: 2017.06.14 DR JOHANNES HEIDENHAIN GMBH
  • EP2551645B1 patent drawingFigure 1
  • EP2551645B1 patent drawingFigure 2~3
  • EP2551645B1 patent drawingFigure 4

AI summary

The device (10) has a graduation carrier (20) provided with a code track (25). Two scanning units (30-33) determine angle values of the carrier by scanning the code track. A control unit (40) includes a device interface (42) that is in communication with a follower electronics unit (100). A control unit interface (45-48) is in communication with the interfaces of the scanning unit. The angle values of the scanning units are requested and processed into a corrected angle value by a processing unit (41), where the corrected value is transmitted to the electronics unit. An independent claim is also included for a method for performing angular measurement.