Multi-Axis Photoelectric Sensor for Stable Workpiece Detection

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Solution Overview

Problem

Conventional multi-optical-axis photoelectric sensors face challenges in detecting complex-shaped work pieces with holes or irregular shapes, and vibration, leading to unstable detection and productivity issues due to the reliance on single-optical-axis sensors.

Innovation Solution

The sensor apparatus automatically adjusts the number of sensing optical axes based on the shape and vibration of the work piece, expanding the range of optical axes to ensure stable detection, and switches between sensing modes to maintain continuous signal supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple independent muting sensors are arranged upstream and downstream of the hazard sensing sensor, then the muting function can be achieved, but the stability of the muting function depends on the performance and stability of external muting signals

Engineering Contradiction:
Improvestability of muting functionVSAvoidnumber of external muting sensors
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the hazard sensing sensor and muting sensor functions into a single integrated sensor device. The light receiving unit includes both hazard sensing photodetectors and muting sensing photodetectors, eliminating the need for separate external muting sensors and improving system reliability by reducing dependency on external signal stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensor device performs multiple functions simultaneously: it acts as both a hazard sensing sensor with multiple optical axes for safety monitoring and a muting sensor for productivity maintenance. This multi-functionality is achieved by incorporating both hazard sensing and muting sensing capabilities within the same light receiving unit.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If single-optical-axis sensors are used for muting detection, then the device complexity is reduced, but the detection stability deteriorates when work pieces have complex shapes or vibration

Engineering Contradiction:
Improvesensor configurationVSAvoiddetection stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent merges the muting sensing capability into the multi-optical-axis hazard sensing sensor. The light receiving unit includes photodetectors that serve both hazard sensing and muting sensing functions, allowing stable detection of complex-shaped work pieces while maintaining simple device configuration.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If the number of optical axes for sensing is increased to detect complex-shaped work pieces, then the detection accuracy improves, but the device complexity increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidnumber of optical axes
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines hazard sensing and muting sensing functions into a single integrated sensor device. The light receiving unit includes both hazard sensing photodetectors and muting sensing photodetectors, eliminating the need for separate external muting sensors and improving system reliability by reducing dependency on external signal stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensor device performs multiple functions simultaneously: it acts as both a hazard sensing sensor with multiple optical axes for safety monitoring and a muting sensor for productivity maintenance. This multi-functionality is achieved by incorporating both hazard sensing and muting sensing capabilities within the same light receiving unit.

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

This approach allows for stable detection of complex-shaped work pieces and those experiencing vibration, preventing false shutdowns of manufacturing equipment and improving productivity by ensuring accurate muting processing.

Implementation Method 1

a light emitting element 51 and a light receiving element 61, and forms an optical axis L1 between them

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Implementation Method 2

receive light along the optical axis with the light receiving element 61

Methodology Applied
Scientific EffectPhotoelectric detection: Photoelectric Effect

Data Source

PatentEP3002615B1Sensor and safety system
Publication Date: 2020.02.26 OMRON CORP
  • EP3002615B1 patent drawingFigure 1
  • EP3002615B1 patent drawingFigure 2
  • EP3002615B1 patent drawingFigure 3

AI summary

Provided is a sensor apparatus according to which a sensing target (work piece W) being conveyed can be sensed appropriately without requiring a complex setting task, regardless of the shape of the sensing target (work piece W) or the existence of vibration. A sensor apparatus includes multiple pairs that each include a light emitting element and a light receiving element configured to receive light emitted from the light emitting element, and, in response to optical axes (L1, L1, etc.) formed in a region between the light emitting elements and the light receiving elements entering a blocked state, senses a sensing target (work piece W) moving in the region. In an initial state, sensing is performed using a sensing optical axis (A1, B1) composed of a portion of the optical axes (L1, L1, etc.), and when an optical axis of the sensing optical axis (A1, B1) used in sensing in the initial state is blocked, the number of optical axes included in the sensing optical axis (A1, B1) is increased so as to expand the sensing optical axis (A1, B1).