Overhead Traveling Vehicle Obstacle Detection

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Solution Overview

Problem

Existing overhead traveling vehicle systems face challenges in reliably detecting obstacles near load ports without mistakenly identifying the local carriage track as an obstacle, which can lead to hindered article transfer and safety issues.

Innovation Solution

The buffers are suspended from the local carriage track by vertical supports, eliminating a frame over the load port, and downward sensors on the carriage track monitor obstacles, while separate sensors detect articles and operators, preventing false obstacle detection and ensuring safe transfer by stopping hoists upon detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a frame is provided over the load port to support buffers, then buffers can be arranged vertically under the local carriage track, but the frame may be mistakenly detected as an obstacle by sensors and may contact hoists or articles during horizontal swinging

Engineering Contradiction:
Improveobstacle detection reliabilityVSAvoidfalse obstacle detection and physical contact risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the frame structure that previously supported the buffers over the load port. Instead, buffers are suspended directly from the local carriage track using vertical supports, eliminating the intermediate frame that caused false obstacle detection and physical contact risks while maintaining the vertical stacking capability of buffers

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent repositions buffers from a horizontal arrangement on a frame over the load port to a vertical suspension arrangement directly under the local carriage track. This dimensional change eliminates the frame structure entirely while maintaining buffer support functionality and improving safety by removing objects from the hazardous zone

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

2Ease of operation

If sensors are positioned to monitor the load port area, then obstacles can be detected, but the local carriage track may be mistakenly identified as an obstacle causing unnecessary transfer stops

Engineering Contradiction:
Improvesafe article transferVSAvoidunnecessary transfer stops
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

By removing the frame structure from over the load port, the patent eliminates the source of false obstacle detection. Sensors can now clearly distinguish between actual obstacles (operators, articles) and the normal operational environment, preventing unnecessary transfer stops while maintaining safety monitoring

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a spatial separation between the buffer support structure and the load port area. By suspending buffers vertically under the track rather than positioning them horizontally over the load port, the system creates a clear distinction between operational zones, allowing sensors to function without false positives

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2878552B1Overhead traveling vehicle system and transfer control method for overhead traveling vehicle system
Publication Date: 2021.01.13 MURATA MASCH LTD
  • EP2878552B1 patent drawingFigure 1
  • EP2878552B1 patent drawingFigure 2
  • EP2878552B1 patent drawingFigure 3

AI summary

An overhead traveling vehicle (4) is prevented from mistakenly detecting a track (10) for a local carriage (8) or the like as an obstacle. The overhead traveling vehicle (4) includes a hoist (22) and a first sensor (38) that monitors obstacles below, and the local carriage (8) includes a hoist (27) and travels along the track (10). A buffer (12) is suspended from the track (10) by vertical supports (32) that extend vertically downward, and no members of the buffer (12) are provided directly over load ports (16, 17). A second sensor (36), which monitors an obstacle that is in a vicinity of the load ports (16, 17) and in a passageway-side area on a side opposite to a processing device (13), is provided on the track (10) and transmits an obstacle detection signal to the overhead traveling vehicle (4) and the local carriage (8). Upon receiving the obstacle detection signal from the second sensor (36), the overhead traveling vehicle (4) and the local carriage (8) stop the hoists (22, 27), and the overhead traveling vehicle (4) does not monitor obstacles in the passageway-side area using the first sensor (38).