Angular Measurement Device with Rotary Member for Cyclic Error Reduction

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Solution Overview

Problem

Existing angular measurement devices, such as encoders and resolvers, suffer from cyclic errors due to non-uniform division and eccentricity, which require calibration and limit accuracy, and provide only incremental information without absolute position until initialization.

Innovation Solution

A device with a rotary member that generates two dynamic AC signals, allowing phase measurement and time interval analysis to reduce cyclic errors and provide absolute position without calibration, using detecting means that autonomously detect references on the rotary member to measure phase differences and rotation speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If classical encoders are used with regular signs on the disk, then the device can measure rotation angle and provide incremental information, but cyclic errors due to non-uniform division and eccentricity limit measurement precision and require calibration

Engineering Contradiction:

Improveangular measurement precisionVSAvoidaccuracy without calibration

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent divides the measurement task into multiple independent detecting means, each reading different references (first references and second references) on the rotary member. This segmentation allows the system to measure multiple parameters simultaneously and independently, enabling error reduction through comparison and correlation of the measurements without requiring calibration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a feedback mechanism where the control unit continuously monitors the phase differences between signals from multiple detecting means and adjusts the measurement calculations accordingly. The system uses the measured phase differences to compensate for cyclic errors in real-time, providing accurate angular measurement without calibration.

Inventive Principle:

Principle #23Feedback

2Productivity

If incremental encoders are used, then the device can measure rotation amount and speed, but absolute position information is unavailable without initialization procedure

Engineering Contradiction:

Improvemeasurement speedVSAvoidabsolute position information

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent makes the detecting means multi-functional by enabling them to read both first references and second references on the rotary member. This universal capability allows the same detecting means to provide both incremental measurement (through phase difference changes) and absolute position information (through the fixed phase relationship between different references), eliminating the need for separate initialization procedures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If optical encoders are used in hostile environments, then high resolution can be achieved, but the device may be damaged by high temperatures, dust, and humidity

Engineering Contradiction:

Improveangular resolutionVSAvoidenvironmental damage

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the vulnerable optical sensing system with a magnetic sensing system. The detecting means use magnetic sensors to read magnetic references on the rotary member, which are immune to environmental factors like dust, humidity, and temperature. This substitution maintains high measurement precision while providing robustness against hostile environments.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The device significantly reduces cyclic errors and achieves high accuracy without calibration, enabling improved angular measurement resolution and absolute position determination, even in hostile environments.

Implementation Method 1

generates two dynamic AC signals, allowing phase measurement and time interval analysis to reduce cyclic errors and provide absolute position without calibration

Methodology Applied

Scientific EffectPhase measurement:

Implementation Method 2

generates two dynamic AC signals, allowing phase measurement and time interval analysis to reduce cyclic errors and provide absolute position without calibration

Methodology Applied

Scientific EffectTime interval analysis:

Implementation Method 3

A device with a rotary member that generates two dynamic AC signals, allowing phase measurement and time interval analysis

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2534451B1Device for angular measures equipped with rotary member

Publication Date: 2016.11.02 IST NAZ DI RICERCA METROLOGICA (I N RI M)

Figure 1~2
Figure 3~4

AI summary

A device (1) for angular measures is described, composed of a first part (3) and a second part (5), each one of such parts (3, 5) being able to relatively rotate one with respect to the other around a rotation axis (R-R); between such parts (3, 5) at least one rotary member (7) is interposed, continuously rotated around such axis (R-R) through actuating means, each one of such parts (3, 5) being equipped with at least one respective detecting means (9, 10) and such member (7) being equipped on its surface with references adapted to be autonomously detected by each one of such detecting means (9, 10).