Tundish Lifting Cylinder Synchronization With Position Deviation Correction

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Solution Overview

Problem

The synchronization control accuracy of hydraulic cylinder synchronization control modes in continuous casting tundishes is affected by factors such as hydraulic system leakage, manufacturing accuracy differences, and uneven loads, leading to asynchronous lifting and potential safety hazards like molten steel overflow and equipment damage.

Innovation Solution

A synchronization control method for lifting hydraulic cylinders using a system with master and slave hydraulic cylinder control subsystems, including position deviation correction units, fault interruption control, and automatic position holding, to ensure synchronous movement and high fault tolerance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydraulic cylinder synchronization control mode based on four hydraulic synchronous motors or universal master/slave hydraulic cylinder synchronization control mode is used, then the lifting hydraulic cylinders can be controlled to move synchronously, but the synchronization control accuracy is easily affected by hydraulic system leakage, different manufacturing accuracy of hydraulic elements, and uneven load

Engineering Contradiction:
Improvesynchronization control accuracyVSAvoidhydraulic system leakage, manufacturing accuracy differences, uneven load
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback control mechanism where the actual positions of all hydraulic cylinders are continuously monitored by a control system. The control system calculates position deviations between the master and slave hydraulic cylinders in real-time, and dynamically adjusts the proportional regulation valves to correct these deviations. This closed-loop feedback ensures high synchronization accuracy despite hydraulic leakage, manufacturing variations, and uneven loads.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces traditional mechanical synchronization mechanisms (such as mechanical linkages or synchronous motors) with an electrical control system that uses sensors, controllers, and proportional regulation valves. This substitution allows for more precise control and better compensation of disturbances compared to pure mechanical systems, as the electrical system can rapidly detect and correct position deviations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If four hydraulic synchronous motors are used for synchronous lifting, then the hydraulic cylinders can be driven simultaneously, but asynchronous lifting occurs due to abnormal working of motors or internal leakage

Engineering Contradiction:
Improvesynchronous lifting operationVSAvoidsynchronization accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Instead of relying on the mechanical synchronization of four hydraulic synchronous motors, the patent uses a feedback control system that continuously monitors the actual position of each hydraulic cylinder and dynamically adjusts their speeds. The control system calculates position deviations and sends correction signals to proportional regulation valves, ensuring all cylinders remain synchronized even if motors or seals fail.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the control parameter from fixed mechanical coupling (in synchronous motors) to dynamic electrical control. The control system continuously adjusts the flow parameters through proportional regulation valves based on real-time position feedback, allowing flexible compensation for motor abnormalities or internal leakage that would cause asynchronous lifting in motor-driven systems.

Inventive Principle:
Principle #35Parameter changes

3Extent of automation

If universal master/slave hydraulic cylinder synchronization control mode with independent PI regulator and proportion regulation valve is used, then synchronous control can be achieved, but asynchronous lifting still occurs due to internal leakage

Engineering Contradiction:
Improveautomatic synchronization controlVSAvoidsynchronization accuracy
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The patent enhances the master/slave control mode with a comprehensive feedback mechanism that monitors all hydraulic cylinders' positions. The control system continuously calculates position deviations between master and slave cylinders and dynamically adjusts proportional regulation valves. This feedback loop compensates for internal leakage and other disturbances, maintaining synchronization accuracy despite the complexity of the automated control system.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3643930B1Synchronous control method based on synchronous control system for lifting hydraulic cylinders of tundish in continuous casting
Publication Date: 2023.10.11 MAANSHAN IRON & STEEL CO LTD
  • EP3643930B1 patent drawingFigure 1
  • EP3643930B1 patent drawingFigure 2
  • EP3643930B1 patent drawingFigure 3

AI summary

The present disclosure is applicable to the hydraulic drive control field, and provides a synchronization control method based on a synchronization control system for lifting hydraulic cylinders of a continuous casting tundish. According to the method, a master hydraulic cylinder synchronization position deviation velocity correction unit and a slave hydraulic cylinder synchronization position deviation velocity correction unit correct a position deviation exceeding a set range between a master hydraulic cylinder and a slave hydraulic cylinder. If the position deviation between the two exceeds a set maximum allowable position deviation, a master hydraulic cylinder synchronization position deviation out-of-range control unit and a slave hydraulic cylinder synchronization position deviation out-of-range control unit control a fast moving master hydraulic cylinder or slave hydraulic cylinder to stop moving, until the position deviation between the two is less than the set maximum allowable position deviation again. A master hydraulic cylinder automatic position holding control unit and a slave hydraulic cylinder automatic position holding control unit are used to avoid position deviation of the master hydraulic cylinder and the slave hydraulic cylinder without a manual instruction. Therefore, according to the synchronization control method, the master hydraulic cylinder and the slave hydraulic cylinder can be synchronously moved in cases of leakage of a hydraulic cylinder, different manufacturing accuracy of hydraulic elements, and uneven load.