Yarn Defect Detection Using Position-Based Winding Speed Calculation
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Solution Overview
Problem
Existing textile machines inaccurately measure yarn speed due to varying actual speed during the winding process, leading to errors in defect detection and reel uniformity, resulting in false positives or negatives and increased waste.
Innovation Solution
Implementing a textile machine with a position sensor and processing unit that accurately calculates yarn speed by considering the speed profile of the yarn guide cylinder and reel diameter, providing precise defect detection and reel square footage calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If average winding speed is used to calculate defect length, then defect detection can be performed, but measurement precision deteriorates due to speed variations during crossing
Solution Approach 1:
The patent uses a mathematical model (speed profile) that is calculated once and stored in memory, replacing the need for complex real-time speed measurement hardware. The model is a lightweight computational solution that provides accurate speed values without requiring additional sensors or complex measurement devices.
Solution Approach 2:
The speed profile is pre-calculated based on the yarn guide cylinder geometry and winding parameters, then stored in the control unit's memory. During operation, the system simply retrieves the pre-calculated speed values corresponding to the current yarn position, avoiding the need for real-time speed measurement while maintaining high precision.
2Measurement precision
If real-time yarn speed measurement is implemented, then defect detection accuracy improves, but device complexity increases due to additional sensors
Solution Approach 1:
The patent replaces physical speed measurement sensors with a mathematical model that calculates yarn speed based on the known geometry of the yarn guide cylinder and the current position of the yarn. The control unit computes the instantaneous speed using the stored speed profile, substituting mechanical sensing with computational calculation.
Solution Approach 2:
The speed profile acts as an intermediary between the yarn guide cylinder geometry and the defect detection system. Instead of directly measuring yarn speed, the system uses the speed profile as a intermediary data structure that translates cylinder geometry and yarn position into accurate speed values for defect length calculation.
3Reliability
If average speed is used for defect detection, then device complexity is reduced, but reliability deteriorates due to false positives and negatives
Solution Approach 1:
The system continuously monitors the yarn position along the crossing and uses this feedback to retrieve the corresponding instantaneous speed from the stored speed profile. This feedback mechanism ensures that the correct speed value is always used for defect length calculation, eliminating errors caused by using average speed during speed variations.
Solution Approach 2:
The patent transitions from using a static average speed value to using dynamic instantaneous speed values retrieved from the speed profile. The system adapts the speed parameter in real-time based on the yarn's position during crossing, ensuring accurate defect length measurement throughout the winding process.
Data Source
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AI summary
Textile machine (4) with improved device for detecting defects of the yarn (12) being wound comprising a spool (8) on which a yarn (12) is unwound and rewound on a reel (16), a reel (16) on which to wind said yarn (12) unwound from said spool (8), a head supporting a yarn guide cylinder (24), rotating about a rotation axis (X-X), said yarn guide cylinder (24) having a plurality of slots (28) which receive and guide the yarn (12) unwound from the spool (8), said slots (28) defining a speed profile (32) of the yarn (12) housed therein, said yarn (12) translating, parallel to said rotation axis (X-X), from a first transverse end or tip (36) of said yarn guide cylinder (24) to a second transverse end or tail (40) of said yarn guide cylinder (24) and vice versa in an alternating manner according to a crossing movement, before being wound onto the reel (16), a clearer (44), arranged between the spool (8) and the yarn guide cylinder (24) so as to analyse the yarn (12) unwound from the spool (8) and not yet wound on the reel (16), to identify possible defects thereof, in a given time interval, the yarn (12) crossing the clearer (44) along a straight direction according to a running speed, at least one position sensor (48) which identifies at least one transverse position (Y) of the yarn (12) with respect to the yarn guide cylinder (24), along said crossing movement, a processing and control unit (52) operatively connected to the clearer (44), to said yarn guide cylinder (24) and to said at least one position sensor (48), and provided with said speed profile (32) of the yarn (12), as a function of the transverse position (Y) of the yarn (12) with respect to the yarn guide cylinder (24), so as to be able to calculate the running speed of the yarn (12) at the clearer (44). The processing and control unit (52) being programmed so as to receive from the at least one position sensor (48) the transverse position (Y) of the yarn (12), calculate the running speed of the yarn (12) upstream of the yarn guide cylinder (24) and send it to the clearer (44) so as to calculate the length of the yarn (12) crossing the clearer (44) in said given time interval.