Mold-Clamping Position Control with Switched Feedback Modes

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Solution Overview

Problem

Conventional positioning control devices for mold-clamping apparatuses require a special servo amplifier to switch between first and second feedback control modes, which can be difficult for general-purpose servo amplifiers to handle, limiting their ability to position a movable body at low costs and high accuracy.

Innovation Solution

A positioning control device with a controller that switches between first and second control modes using a switching unit, allowing the servo amplifier to perform first feedback control when the movable body is far from the target and second feedback control when close, eliminating the need for a special servo amplifier and enabling high-accuracy positioning without relying on it.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a special servo amplifier is used to switch between first and second feedback control modes, then positioning accuracy is improved, but device complexity and cost increase

Engineering Contradiction:
Improvepositioning accuracyVSAvoidservo amplifier complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The feedback control mode switching function is extracted from the servo amplifier and transferred to a separate controller. This allows the servo amplifier to remain a simple, general-purpose device while the controller handles the complex logic of switching between first feedback control (when the movable body is far from the target) and second feedback control (when close to the target), thereby resolving the contradiction between positioning accuracy and device complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A separate controller acts as an intermediary between the servo amplifier and the feedback control system. This intermediary handles the complex switching logic between different control modes, allowing the servo amplifier to remain simple and general-purpose while still achieving high positioning accuracy through coordinated control

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a special servo amplifier is used to handle feedback control switching, then control functionality is improved, but ease of manufacture and cost worsen

Engineering Contradiction:
Improvecontrol functionalityVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The controller is designed to universally handle multiple control functions including switching between first and second feedback control modes, position calculation, and coordination with the servo amplifier. This multi-functional controller allows the use of standard, off-the-shelf servo amplifiers rather than requiring expensive custom-designed special servo amplifiers, thereby improving ease of manufacture and reducing costs while maintaining full control functionality

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If second feedback control is performed throughout the entire movable range, then positioning accuracy is improved, but device complexity and cost increase

Engineering Contradiction:
Improvepositioning accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The movable range is segmented into two zones: a first region where first feedback control is used (when the movable body is far from the target position) and a second region where second feedback control is used (when close to the target position). This segmentation allows the system to use simpler control methods when high precision is not required and switches to more complex control only when necessary, thereby reducing overall device complexity and cost while maintaining positioning accuracy where it matters most

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3473403B1Positioning control device and mold-clamping apparatus
Publication Date: 2021.11.24 MURATA MASCH LTD
  • EP3473403B1 patent drawingFigure 1
  • EP3473403B1 patent drawingFigure 2
  • EP3473403B1 patent drawingFigure 3

AI summary

A positioning control device mounted on an industrial machine including a driver including a motor, a movable body movable by the driver, a first detector that detects a position of the movable body based on the amount of driving of the driver, a servo amplifier that performs first feedback control of feedback-controlling driving of the motor based on a first detection value by the first detector, and a second detector that detects a position of the movable body when the movable body comes closer to a target position within a certain distance or shorter. The positioning control device is configured to position the movable body at the target position and includes a controller that controls the servo amplifier. The controller includes a switching unit that switches control modes between a first control mode performing the first feedback control and a second control mode disabling the first feedback control of the servo amplifier and performing second feedback control of feedback-controlling driving of the motor based on a second detection value by the second detector.