Rail-Guided Carrier Mark Layout for Compact Position Sensing

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Solution Overview

Problem

Conventional rail systems for tracked carts lack the ability to dispose two types of marks indicating different information on the same location without increasing the cart's size, as they only have one surface for mark disposition.

Innovation Solution

The tracked cart system features a track with first and second surfaces on each rail, allowing two types of marks to be disposed on different surfaces, with the second surface inclined towards the cart, enabling sensors to detect these marks without protruding, thus maintaining cart size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If two surfaces are formed on the rail to dispose two types of marks, then two types of marks can be disposed on the same location, but the size of the tracked cart increases due to the need for sensors to face these surfaces

Engineering Contradiction:
Improveinformation from marksVSAvoidsize of tracked cart
Core Design Contradiction:
Loss of informationVSVolume of moving object

Solution Approach 1:

The rail is designed with two different surfaces (first surface and second surface) that are inclined relative to each other, allowing marks to be disposed on different dimensional planes. This enables two types of marks to be placed at the same longitudinal location without requiring the sensor to protrude, as the inclined surfaces bring both mark types within reach of the sensor's detection range.

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

2Measurement precision

If the second sensor protrudes from the tracked cart to face the second surface, then the second mark can be detected, but the size of the tracked cart increases

Engineering Contradiction:
Improvedetection of second markVSAvoidsize of tracked cart
Core Design Contradiction:
Measurement precisionVSLength of moving object

Solution Approach 1:

The second surface is designed to be asymmetrically inclined toward the tracked cart relative to the first surface. This asymmetric inclination allows the second mark to be positioned closer to the tracked cart body, enabling the second sensor to detect the mark without protruding outward, thus maintaining a compact cart structure while ensuring detection capability.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP4592158A1Rail-guided carrier system
Publication Date: 2025.07.30 MURATA MASCH LTD
  • EP4592158A1 patent drawingFigure 1
  • EP4592158A1 patent drawingFigure 2
  • EP4592158A1 patent drawingFigure 3

AI summary

The overhead traveling vehicle system includes a track in which a plurality of first rails extends in an X direction and a plurality of second rails extends in a Y direction in a grid, and a traveling vehicle travels on a pair of the first rails adjacent to each other in the Y direction and travels on a pair of the second rails adjacent to each other in the X direction, in which each of the first rail and the second rail has a first surface on which a cell recognition mark is disposed and a second surface on which a position recognition mark is disposed, the second surface, when viewed from a center of a cell in plan view, being disposed outside the first surface and being inclined toward the traveling vehicle 2 side with respect to the first surface.