Overhead transport vehicle and method for calculating rotation amount of winding drum in overhead transport vehicle

Patent metadata

Field	Value
Publication number	US-12014945-B2
Application number	US-202117463744-A
Country	US
Kind code	B2
Filing date	Sep 1, 2021
Priority date	Oct 7, 2020
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

An overhead transport vehicle includes a lift stage to transfer an article, a winding drum to overlap and wind a suspension attached to the lift stage, and a controller to control a rotation amount of the winding drum to control a lifting/lowering amount of the lift stage. The controller is configured or programmed to execute a first processing including calculating, as individual values of the overhead transport vehicle, an individual value of an entire length of the suspension, an individual value of a diameter of the winding drum, and an individual value of a thickness of the suspension, and a second processing including calculating a rotation amount of the winding drum with respect to a lifting/lowering amount of the lift stage.

First claim

What is claimed is:

1. An overhead transport vehicle comprising:
a lift stage to transfer an article;
a winding drum to overlap and wind a suspension attached to the lift stage; and
a controller to control a rotation amount of the winding drum to control a lifting/lowering amount of the lift stage; wherein
the controller is configured or programmed to execute:
a first processing including calculating, as individual values of the overhead transport vehicle, an individual value of an entire length of the suspension, an individual value of a diameter of the winding drum, and an individual value of a thickness of the suspension; and
a second processing including calculating a rotation amount of the winding drum with respect to a lifting/lowering amount of the lift stage based on the individual value of the entire length of the suspension, the individual value of the diameter of the winding drum, and the individual value of the thickness of the suspension calculated in the first processing.

2. The overhead transport vehicle according to claim 1 , wherein in the first processing, the individual value of the entire length of the suspension, the individual value of the diameter of the winding drum, and the individual value of the thickness of the suspension are calculated using a fact that the lifting/lowering amount of the lift stage is approximated by a square function of the rotation amount of the winding drum, the square function including as coefficients, the individual value of the entire length of the suspension, the individual value of the diameter of the winding drum, and the individual value of the thickness of the suspension.

3. The overhead transport vehicle according to claim 2 , wherein in the first processing, the individual value of the entire length of the suspension, the individual value of the diameter of the winding drum, and the individual value of the thickness of the suspension are calculated based on a data group including two or more pieces of sample data including the lifting/lowering amount of the lift stage and the rotation amount of the winding drum at a time of that lifting/lowering amount.

4. The overhead transport vehicle according to claim 3 , wherein in the first processing, the individual value of the entire length of the suspension, the individual value of the diameter of the winding drum, and the individual value of the thickness of the suspension are calculated based on the following equations:

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C
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Assignees

• Murata Machinery Ltd

Inventors

• Suriki Keiichiro
• Aomoto Kazuya

Classifications

• H10P72/3214

  by means of a cart or a vehicle · CPC title

• H10P72/0606

  Position monitoring, e.g. misposition detection or presence detection · CPC title

• H10P72/3221 Primary

  Overhead conveying · CPC title

• H10P72/53

  using optical controlling means · CPC title

• H10P72/3222

  Loading to or unloading from a conveyor · CPC title