Yarn Unwinding Control via Dynamic Threshold
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Solution Overview
Problem
Conventional yarn unwinding control systems require initial calibration and a speed signal from the downstream machine, and are not adaptable to fluctuating yarn consumption, leading to inefficiencies and potential false stoppage detections in textile processes.
Innovation Solution
A method that continuously counts the relative operating position of the machine and calculates a threshold based on yarn pickup rate, generating a stop signal when the position exceeds a dynamically calculated threshold, without the need for initial calibration or a speed signal, allowing for automatic adaptation to yarn consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional yarn breakage sensors (mechanical or electronic) are used to detect stoppages, then stoppage detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses the existing unwinding pulses (a copy of the yarn movement information) to detect stoppages, rather than installing additional dedicated sensors. The control unit analyzes the timing of these existing pulses to infer stoppage conditions, eliminating the need for separate detection devices.
Solution Approach 2:
The control unit performs multiple functions: it generates stop signals based on unwinding pulse analysis, controls yarn tension, and manages the overall feeding process. This multi-functionality eliminates the need for separate dedicated stoppage detection devices, reducing system complexity.
2Device complexity
If mechanical sensors are used for stoppage detection, then device complexity is reduced, but response time and yarn tension control precision deteriorate
Solution Approach 1:
The patent replaces mechanical sensors with an electronic control system that analyzes unwinding pulse timing. This electronic approach provides faster response times compared to mechanical sensors while maintaining simplicity by using existing pulse signals rather than adding complex electronic sensor assemblies.
3Device complexity
If fixed threshold values are used for stoppage detection, then device complexity is reduced, but adaptability to varying yarn consumption deteriorates
Solution Approach 1:
The patent implements dynamic threshold adjustment where the control unit continuously adapts the stoppage detection threshold based on actual yarn consumption patterns observed during operation. This allows the system to automatically adjust to varying consumption rates without requiring complex pre-programming or manual intervention.
Solution Approach 2:
The control system automatically adapts to varying yarn consumption by analyzing actual operational data and adjusting its own detection parameters. This self-adjusting capability eliminates the need for external calibration or manual intervention while maintaining simplicity.
4Measurement precision
If initial calibration step is implemented, then measurement precision is improved, but productivity and ease of operation deteriorate
Solution Approach 1:
The control unit automatically performs calibration by analyzing actual yarn consumption during normal operation and adjusting its detection parameters accordingly. This self-calibration approach eliminates the need for manual initial calibration steps while maintaining measurement precision through continuous adaptive adjustment.
Data Source
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AI summary
Method for controlling the unwinding of yarn from a weft feeder wherein detection means (18) generate unwinding pulses (UWP) that indicate the release of a turn or fraction of a turn of yarn from a feeder (10); a continuous count is made of a relative operating position (NPSD_CNT) of a textile machine (16), measured from the last unwinding pulse (UWP); the amount of yarn picked up at each machine revolution (YCPR) is calculated continuously, as well as a threshold operating position (NPSD) as a function of the variation of position corresponding to a machine revolution, of a maximum length of yarn that can be inserted in the machine and can be chosen by the user, and of the amount of yarn picked up at each machine revolution; when the relative operating position (NPSD_CNT) equals or exceeds the threshold operating position (NPSD), a stop signal is generated.