Multi-DOF Displacement Measuring Device Using Rotary Scale Patterns

Solution Overview

Problem

Conventional rotary encoders are inadequate for accurately measuring complex multi-degree-of-freedom displacements in robots and machine tools, as they can only detect rotation angles and speeds, failing to capture movements involving multiple axes and misalignments, which leads to increased equipment size and complexity.

Innovation Solution

A multi-degree-of-freedom displacement measuring device comprising a rotary scale with patterns around a first rotation axis and a detection head group that calculates relative rotation angles and movement amounts along multiple axes using electromagnetic induction principles, allowing for simultaneous detection of eccentricity and inclination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional rotary encoder is used to detect rotation angle, then the device structure is simple, but it cannot measure multi-degree-of-freedom displacements including movements along multiple axes and misalignments

Engineering Contradiction:

Improvemeasurement capabilityVSAvoiddevice structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The rotary encoder is designed to perform multiple measurement functions simultaneously. By arranging multiple detection heads around the rotation axis and detecting patterns at different radial positions, a single device can measure rotation angles around the rotation axis, movements along the rotation axis, and movements along orthogonal axes, eliminating the need for multiple separate measurement devices

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces measurement capabilities in additional dimensions by detecting patterns at multiple radial positions from the rotation axis. This allows the system to measure not only rotational movement but also linear movements along the rotation axis and orthogonal axes, transforming a single-axis rotation detector into a multi-degree-of-freedom measurement system

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If multiple separate measurement devices are used to capture multi-degree-of-freedom displacements, then measurement precision is improved, but equipment size and complexity increase

Engineering Contradiction:

Improvedisplacement measurement accuracyVSAvoidequipment size

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple measurement functions into a single integrated rotary encoder system. Multiple detection heads are arranged around the rotation axis, with each detection head capable of detecting patterns at different radial positions. This merging of functions allows the system to achieve comprehensive multi-degree-of-freedom measurement capability that would otherwise require multiple separate devices

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The rotary encoder is designed to perform multiple measurement functions simultaneously. By arranging multiple detection heads around the rotation axis and detecting patterns at different radial positions, a single device can measure rotation angles around the rotation axis, movements along the rotation axis, and movements along orthogonal axes, eliminating the need for multiple separate measurement devices

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables accurate measurement of complex displacements, reducing the need for additional monitoring devices and simplifying equipment setup by providing comprehensive position information across multiple axes, enhancing precision and reducing equipment size.

Implementation Method 1

A multi-degree-of-freedom displacement measuring device comprising a rotary scale with patterns around a first rotation axis and a detection head group that calculates relative rotation angles and movement amounts along multiple axes using electromagnetic induction principles

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20240230378A1Multi-degree-of-freedom displacement measuring device and multi-degree-of-freedom displacement measuring method

Publication Date: 2024.07.11 MITUTOYO CORP

AI summary

A multi-degree-of-freedom displacement measuring device includes a rotary scale that has a scale pattern including a plurality of patterns that are arranged around a first rotation axis and arrayed along a circumference direction of the rotary scale, a detection head group including a plurality of detection heads, each of which is provided around the first rotation axis, is arranged on an installation face facing the rotary scale, and is configured to detect each of the plurality of patterns from the scale pattern, and a calculator configured to, based on detection values acquired by the plurality of detection heads, calculate a relative rotation angle around the first rotation axis, and calculate at least one of a relative movement amount in a direction along the first rotation axis and a relative movement amount in a direction along a second rotation axis orthogonal to the first rotation axis.