Coating Weight Control via Strip Position Estimation
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Solution Overview
Problem
Existing coating weight control methods in hot-dip coating plants face challenges in accurately controlling coating weights on both sides of a steel strip while preventing nozzle-strip contact, often requiring costly sensors and failing to account for strip thickness, tension, and correcting roll position changes, leading to reduced accuracy and increased risk of contact.
Innovation Solution
A coating weight control apparatus that estimates the movement of the strip passing position without a special sensor, using a prediction model to control nozzle pressures and positions based on strip speed, nozzle pressures, and distances, ensuring balanced coating weights and safe operation by adjusting nozzle positions in response to changes in strip thickness, tension, and correcting roll position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a sensor for detecting strip passing position is installed, then automatic control of nozzle position becomes possible, but system cost increases and additional maintenance is required
Solution Approach 1:
The system uses readily available sensors (strip thickness sensor, tension sensor, correcting roll position sensor) that already exist in the coating plant to automatically detect strip passing position changes, eliminating the need for dedicated position detection sensors and their associated maintenance
Solution Approach 2:
The invention introduces a control unit that acts as an intermediary, calculating strip passing position changes by synthesizing information from multiple existing sensors (strip thickness, tension, correcting roll position) rather than directly measuring position, thereby avoiding the need for expensive position detection sensors
2Manufacturing precision
If nozzle position is controlled manually, then contact risk is reduced, but coating weight accuracy and balance deteriorate
Solution Approach 1:
The system continuously monitors strip parameters (thickness, tension, correcting roll position) and automatically adjusts nozzle position in real-time based on detected changes, maintaining both coating accuracy and safety without manual intervention
Solution Approach 2:
The invention replaces manual mechanical position adjustment with automated control based on calculated strip passing position changes, using computational methods to determine optimal nozzle positions while preventing contact
3Ease of operation
If sensor for detecting strip passing position is disposed in upper portion of nozzle, then detection is simplified, but detection accuracy deteriorates due to vibration and warp
Solution Approach 1:
The control unit serves as an intermediary that calculates strip passing position changes by combining data from multiple sensors (strip thickness sensor, tension sensor, correcting roll position sensor) rather than relying on a single position detection sensor, thereby achieving high accuracy without direct position measurement
Solution Approach 2:
The invention replaces direct mechanical position detection with a computational approach that calculates position changes based on measured physical parameters (thickness, tension, roll position), eliminating the problems associated with direct position sensing in vibrating environments
Data Source
AI summary
A coating weight control apparatus includes: a strip passing position movement amount estimate part configured to estimate an movement amount of a strip passing position, in response to any of activation factors for movement of a strip passing position, that is, a welding point passing, a change in tension, and an operation of a correcting roll; and a nozzle position control part configured to shift each of positions of a front side nozzle and a back side nozzle by an amount corresponding to the movement amount of the strip passing position estimated by the strip passing position movement amount estimate part.