Library Device Encoder Verification Control

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Solution Overview

Problem

Existing library devices fail to verify the movement distance of the accessor mechanism using an encoder count number when the correlation between the number of pulses of a stepping motor and the encoder count number changes, due to extrinsic factors such as changes in the module gears.

Innovation Solution

A library device with a control mechanism that includes a movement control means to drive the accessor mechanism using stepping motor pulses, a verifying means to compare actual and assumed encoder count numbers, and an adjustment means to determine a proof factor for calculating the assumed encoder count number, ensuring accurate verification of movement distance even if the pulse-count correlation changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the number of pulses of the stepping motor is used to control the movement distance of the accessor mechanism, then the movement can be controlled according to the desired distance, but the correlation between the number of pulses and the encoder count number may change due to extrinsic factors such as changes in module gears, causing the accessor mechanism to fail to reach the designated position

Engineering Contradiction:
Improvemovement controlVSAvoidposition accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces a feedback mechanism where the control device compares the actual encoder count number (obtained from the encoder sensor during motor pulse driving) with the assumed encoder count number (calculated based on the number of motor pulses). This feedback loop enables the system to detect deviations in movement distance and adjust the correlation between pulse counts and encoder readings, ensuring the accessor mechanism reaches the correct designated position even when extrinsic factors cause changes in the pulse-encoder correlation.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the correlation between the number of pulses of the stepping motor and the encoder count number is assumed to be fixed, then the movement distance can be verified using the encoder count number, but the verification fails when extrinsic factors cause changes in the correlation, such as changes in module gears

Engineering Contradiction:
Improvemovement distance verificationVSAvoidcorrelation stability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent transforms the fixed correlation assumption into a dynamic, adjustable correlation. The control device determines a proof factor based on the actual encoder count number and the number of motor pulses, allowing the correlation between pulses and encoder readings to adapt to changes caused by extrinsic factors. This dynamic adjustment maintains measurement precision for movement distance verification while accommodating variations in the mechanical system, such as changes in module gears.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2551852B1Library device, control method, and program
Publication Date: 2019.08.07 NEC PLATFROMS LTD
  • EP2551852B1 patent drawingFigure 1
  • EP2551852B1 patent drawingFigure 2A~2C
  • EP2551852B1 patent drawingFigure 3A~3B

AI summary

A library device in which, even if the relation between the number of pulses of a stepping motor and an encoder count number changes, a movement distance of a medium transfer means can be verified by an encoder count number counted by an encoder sensor is provided. A control means (2) determines a proof factor used when calculating an assumed encoder count number assumed based on the number of pulses according to a movement distance of a medium transfer means (5). When a movement distance of the medium transfer means (5) is verified, an assumed encoder count number, which is assumed based on the above-mentioned determined proof factor and the number of pulses according to the movement distance of the medium transfer means (5), and an actual encoder count number, which is counted by an encoder sensor when a stepping motor is driven by the number of pulses according to the movement distance of medium transfer means (5), are compared.