Mirror-Assisted Workpiece Alignment for Precise Relative Positioning

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Solution Overview

Problem

Existing robot control systems face challenges in accurately aligning objects when assembling them to a fixed receiving object, requiring precise relative alignment between the object and the receiving object.

Innovation Solution

An alignment device comprising a holding device, a moving device, a mirror member, an image sensor, and a control device that calculates the position of the second workpiece relative to the first workpiece based on captured images and performs feedback control to align the second workpiece with the first workpiece, using a mirror to reflect the second workpiece and capture its image simultaneously with the first workpiece.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single camera is used to image objects from multiple directions, then the device complexity is reduced, but the measurement precision of relative alignment deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidmeasurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

A mirror member is introduced as an intermediary optical element to reflect light from the second workpiece to the image sensor. This allows the single camera to capture images of both workpieces simultaneously from different spatial perspectives, enabling accurate relative alignment measurement without requiring multiple cameras or complex multi-directional imaging systems

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mirror member redirects the optical path from the second workpiece into the imaging plane of the single camera, effectively adding a spatial dimension to the imaging capability. This allows the image sensor to capture both the first workpiece (directly) and the second workpiece (via reflection) in the same image frame, achieving precise relative position measurement with simplified device configuration

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If the second workpiece is arranged away from the first workpiece, then the ease of operation for positioning is improved, but the measurement precision of relative alignment deteriorates

Engineering Contradiction:
Improveease of operationVSAvoidmeasurement precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system captures images of both workpieces simultaneously, calculates their relative positions and orientations from the captured images, and uses this information to guide the positioning process. This visual feedback mechanism enables accurate relative alignment even when workpieces are initially positioned at a distance, as the system can continuously monitor and adjust based on the captured images

Inventive Principle:
Principle #23Feedback

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 alignment device achieves more accurate relative alignment between the first and second workpieces by calculating their positions and angles through image processing and feedback control, ensuring precise assembly.

Implementation Method 1

a mirror member capable of reflecting the second workpiece, the mirror member being arranged adjacent to the first workpiece in a second direction intersecting the first direction

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3878606B1Alignment device
Publication Date: 2025.01.01 OMRON CORP
  • EP3878606B1 patent drawingFigure 1
  • EP3878606B1 patent drawingFigure 2
  • EP3878606B1 patent drawingFigure 3

AI summary

An alignment device includes a holding device capable of holding the second workpiece, a moving device that moves the holding device toward the first workpiece, a mirror member capable of reflecting the second workpiece, the mirror member being arranged adjacent to the first workpiece, an image sensor arranged to be able to simultaneously and continuously capture the first workpiece and a mirror image of the second workpiece reflected on the mirror member, and a control device that performs feedback control of the moving device based on the calculated position of the second workpiece with respect to the first workpiece based on the first workpiece and the mirror image of the second workpiece, which are captured by the image sensor, to align the second workpiece with the first workpiece.