Linear Sensor Array for Conveyor Workpiece Detection

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Solution Overview

Problem

Existing devices for emptying transport carriers with randomly arranged workpieces face accuracy errors due to angle changes and shading issues, which hinder optimal detection and removal of workpieces, especially those near side walls or under bulges.

Innovation Solution

A sensor arrangement with at least two image sensors and two laser units, permanently connected and movable linearly above the transport carrier, ensuring no angle changes and optimal illumination of all areas, including corners and shadowed regions, using a fixed angle configuration to minimize shadows and detect workpieces accurately.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a swiveling laser unit is used to project laser beams over the detection area, then the field of view can be adjusted, but angle changes occur causing accuracy errors in position data

Engineering Contradiction:
Improvefield of view adjustmentVSAvoidposition data accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system divides the detection task into multiple fixed laser units instead of using one swiveling unit. Each laser unit is positioned at a different fixed angle, collectively covering the entire detection area without requiring angle changes during operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of making the laser unit swivel to change the field of view, the invention inverts the approach by using multiple fixed laser units positioned to cover different areas. The field of view is expanded through spatial distribution rather than angular movement.

Inventive Principle:
Principle #13The other way round (Inversion)

2Area of stationary object

If the sensor arrangement is positioned to cover the detection area, then workpieces can be detected, but shadows are created preventing detection of workpieces near side walls

Engineering Contradiction:
Improvedetection coverage areaVSAvoidshadowing effect
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The lighting function is segmented into multiple laser units positioned at different locations and angles. This distributes the light sources throughout the detection area, ensuring that no single shadow can obscure the entire view and allowing detection of workpieces near side walls.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different laser units are positioned to provide localized illumination from specific angles, creating optimal lighting conditions for different regions of the transport carrier. This ensures that each area, including shadow-prone regions near side walls, receives adequate illumination.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If multiple image sensors and laser units are used to eliminate shadows and improve detection, then detection accuracy improves, but device complexity increases

Engineering Contradiction:
Improveworkpiece detection accuracyVSAvoidsensor arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention combines multiple image sensors and laser units into a single integrated sensor arrangement that moves as one unit. This merging reduces the complexity of coordinating multiple independent systems while maintaining the detection accuracy benefits of multiple sensors.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensor arrangement is designed to perform multiple functions simultaneously: detection, illumination, and positioning. By making the entire assembly linearly movable, the system achieves versatility in detecting workpieces at various positions without requiring separate mechanisms for each function.

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 solution enables precise and error-free topographic imaging of transport carriers, ensuring complete and collision-free emptying of workpieces, regardless of size or configuration, optimizing cycle time and allowing real-time operation.

Implementation Method 1

a sensor arrangement with at least two image sensors and at least two laser units

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

Workpieces illuminated in this way can be removed from a box or container by a robot

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 3

a fixed camera capturing the resulting points of light

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 4

the sensor arrangement serves to create a topographical surface image of the contents of the respective transport carrier

Methodology Applied
Scientific EffectTriangulation: Geometry

Data Source

PatentEP3184958B1Apparatus for emptying a conveyor with an apparatus for workpiece identification and/or workpiece position detection of a plurality of arbitrary disposed workpieces within the conveyor and gripping apparatus for emptying the conveyor
Publication Date: 2020.03.18 LIEBHER VERZAHNTECHNIK GMBH
  • EP3184958B1 patent drawingFigure 1~2
  • EP3184958B1 patent drawingFigure 3~4

AI summary

The invention relates to a device for workpiece identification and/or workpiece position detection of a plurality of workpieces within a transport carrier by means of a sensor arrangement comprising at least two image sensors and at least two laser units. According to the invention, the image sensors and the laser units of the sensor arrangement are rigidly connected to one another by means of connecting elements and are linearly movable above the transport carrier.