Edge Detection Assembly for Conveyor Vehicle Sorting

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Solution Overview

Problem

In conveyor and sorter systems, accurately detecting the transfer of objects from or to conveyors is challenging, especially for objects of varying shapes, sizes, and optical properties, leading to potential delays or errors in vehicle movement within material handling systems.

Innovation Solution

The implementation of an object sensing arrangement using a collimated optical energy source and a linear array of photodetectors, which emits a diverging beam to detect the leading and trailing edges of objects, ensuring accurate detection regardless of object shape, size, or opacity, and a sensing logic circuit to signal state changes, facilitating reliable transfer confirmation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional sensors are used to detect object transfer, then the system structure remains simple, but detection accuracy deteriorates for thin or transparent objects

Engineering Contradiction:
Improvedetection accuracyVSAvoidsensing arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensing arrangement is segmented into multiple photodetector elements arranged in a line, each detecting light at different positions. This segmentation allows the system to detect objects of various sizes and shapes by monitoring which specific elements are blocked, thereby improving detection accuracy for thin or transparent objects while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A collimated light source is introduced as an intermediary between the sensor and the object. The light source projects a structured light pattern that interacts with the object's physical properties (opacity, transparency, thickness), creating detectable variations in the light field that pass through to the photodetector array, enabling accurate detection of otherwise difficult-to-detect objects.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the vehicle waits for transfer confirmation before returning to charging station, then transfer reliability is ensured, but system productivity decreases due to delays

Engineering Contradiction:
Improvetransfer confirmation reliabilityVSAvoidvehicle utilization efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The sensing arrangement performs detection continuously and in advance, identifying objects on the conveyor before they complete the transfer. This preliminary detection allows the system to predict transfer completion and prepare for the vehicle's return to charging station ahead of time, ensuring reliability while minimizing delays and improving productivity.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If a collimated optical energy source with photodetector array is used, then detection precision for varied objects is improved, but energy consumption increases

Engineering Contradiction:
Improveobject detection precisionVSAvoidoptical energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

Instead of using a single high-power omnidirectional light source, the system employs a collimated optical energy source that concentrates light in a specific direction, and a linear array of photodetectors that focuses detection on the relevant transmission path. This local quality approach reduces energy waste in unnecessary directions while maintaining high detection precision for objects with varying shapes, sizes, and optical properties.

Inventive Principle:
Principle #3Local quality

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 detection of object transfer completion, reducing delays and errors, and allowing vehicles to return to charging stations without incomplete transfers, even for thin or transparent objects, thereby enhancing system efficiency and reliability.

Implementation Method 1

emits a diverging beam to detect the leading and trailing edges of objects

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

linear array of photodetectors

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3575006B1Apparatus for sorting items
Publication Date: 2022.12.28 AMAZON TECH INC
  • EP3575006B1 patent drawingFigure 1~2B
  • EP3575006B1 patent drawingFigure 3A~3B
  • EP3575006B1 patent drawingFigure 4

AI summary

An apparatus for sorting a plurality of items includes a plurality of sort destinations and a plurality of delivery vehicles (400) for delivering items to the sort destinations. Each vehicle includes a surface for supporting items to be delivered and an edge-detection assembly (404) for detecting an edge of an item when the item is conveyed onto or discharged from the vehicle. The edge-detection assembly includes an emitter (104) for emitting a beam of light toward the surface. The emitter is positioned below the surface so that the beam of light is projected transverse the surface. The emitter edge-detection assembly also includes a plurality of detectors (106) for detecting the beam of light, wherein an object on the surface of the vehicle affects the beam of light received by the detectors.