Carriage Motion Control for Variable-Load Workpiece Conveyance

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Solution Overview

Problem

Conventional conveyance systems are inefficient when handling a variety of workpieces with different machining times, as they rely on fixed acceleration/deceleration parameters, leading to potential decreases in operating efficiency and machining accuracy.

Innovation Solution

A conveyance system with a main controller and local controller that adjusts the carriage's movement based on the number of conveyance requests, using different traveling control parameters to manage workload, reducing load on the device by moving more slowly when requests are low.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the conveyance device moves at high speed with fixed acceleration/deceleration parameters, then productivity is improved, but machining accuracy deteriorates due to vibrations

Engineering Contradiction:
Improveconveyance speedVSAvoidmachining accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the acceleration/deceleration parameters changeable based on real-time system status. The control device switches between first parameters (for high speed when system is busy) and second parameters (for low speed when system is idle), allowing the conveyance device to adapt its movement characteristics to current operational conditions, thus resolving the contradiction between productivity and machining accuracy

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the acceleration/deceleration parameters dynamically. When the system is busy with multiple conveyance requests, first parameters enabling high speed are used. When the system is idle, second parameters enabling low speed are applied. This parameter switching mechanism allows the system to optimize both productivity and machining accuracy according to actual operational needs

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the conveyance device uses high acceleration/deceleration for quick positioning, then productivity is improved, but reliability deteriorates due to vibrations affecting machining

Engineering Contradiction:
Improvepositioning speedVSAvoidmachining stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control device dynamically adjusts acceleration/deceleration parameters based on system busy status. When multiple conveyance requests are pending, high acceleration parameters are applied for quick positioning. When the system is idle, low acceleration parameters are used to minimize vibrations. This dynamic adaptation ensures both productivity and reliability are maintained according to real-time conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback by monitoring the number of retained conveyance requests in real-time. Based on this feedback information, the control device automatically selects appropriate acceleration/deceleration parameters, creating a closed-loop control system that adjusts positioning behavior to maintain machining stability while preserving productivity when needed

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If the system handles a variety of workpieces with different machining times, then adaptability is improved, but productivity deteriorates due to ineffective fixed-parameter control

Engineering Contradiction:
Improveworkpiece variety handlingVSAvoidconveyance efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent applies dynamics by making the control parameters adaptive to different workpiece types and machining times. Instead of using fixed parameters, the system dynamically adjusts acceleration/deceleration based on the current workload and machining duration, enabling efficient handling of diverse workpieces while maintaining high conveyance productivity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements parameter changes by switching between different acceleration/deceleration parameter sets based on the specific machining requirements. When machining times vary significantly, the control device adjusts parameters to optimize both the handling of diverse workpieces and the overall conveyance efficiency, preventing productivity loss that would result from rigid fixed-parameter control

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3971112B1Transport system
Publication Date: 2024.07.17 MAKINO J CO LTD
  • EP3971112B1 patent drawingFigure 1
  • EP3971112B1 patent drawingFigure 2
  • EP3971112B1 patent drawingFigure 3~5

AI summary

This conveyance system (190) comprises: a main control device (150) that receives a conveyance request for a workpiece (W) from a plurality of processing machines (1A, 1B); and a conveyance device (100) that conveys the workpiece (W) between a storage shelf (2) and the plurality of processing machines (1A, 1B). The main control device (150) transmits a standby signal indicating whether or not a plurality of conveyance requests are held in the main control device (150). A local control device (70) of the conveyance device (100) moves a carriage (10) with a first travel control parameter when the standby signal indicates that the plurality of conveyance requests are held in the main control device (150), and moves the carriage (10) with a second travel control parameter when the standby signal indicates that the plurality of conveyance requests are not held in the main control device.