Yarn Consumption Control via Dynamic Tension Adjustment
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Solution Overview
Problem
Existing methods for controlling yarn consumption rate in textile machines, particularly large-diameter knitting machines and machines for stockings, are inadequate as they either require costly adjustments to knit triangle controllers or fail to maintain consistent yarn consumption, leading to defects in finished garments, especially in knitting steps with constant consumption.
Innovation Solution
A method and apparatus that utilize a triplet of sensors to measure and control yarn consumption rate by adjusting the reference tension based on measured consumption rates, enabling precise control of yarn consumption without modifying knit triangles, using a control unit connected to the knitting machine via a bus for feedback and alarm systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If yarn tension is controlled by modulating braking to stabilize tension on a preset value, then yarn tension stability is improved, but yarn consumption rate control deteriorates
Solution Approach 1:
The control system is segmented into two independent control loops: a tension control loop that stabilizes yarn tension by modulating braking, and a consumption control loop that regulates yarn consumption rate by adjusting drum rotation speed. This segmentation allows each loop to independently optimize its specific parameter without interfering with the other.
Solution Approach 2:
The invention introduces dynamic adjustment of drum rotation speed based on measured consumption rate, making the system adaptive. The control unit continuously monitors consumption rate and dynamically modifies the drum's rotational velocity to maintain the desired consumption rate, while tension control independently manages tension stability through braking modulation.
2Manufacturing precision
If knit triangles of the textile machine are adjusted to compensate yarn rate variations, then yarn consumption control is improved, but device complexity and cost increase
Solution Approach 1:
The invention implements a feedback control system where a velocity sensor continuously measures the actual yarn consumption rate, and the control unit compares this measured value with the desired consumption rate. Based on this feedback, the control unit automatically adjusts the drum rotation speed to minimize the difference between actual and desired consumption rates, eliminating the need for complex knit triangle adjustments.
Solution Approach 2:
The control unit acts as an intermediary between the velocity sensor and the drum drive mechanism. It processes the consumption rate information from the sensor and generates appropriate control signals to adjust the drum rotation speed, thereby mediating the control of yarn consumption without requiring modifications to the knitting machine's knit triangle controllers.
3Ease of operation
If yarn consumption rate is not controlled on large-diameter knitting machines, then ease of operation is maintained, but manufacturing precision deteriorates due to stripes in finished garment
Solution Approach 1:
The system performs self-service control by automatically monitoring its own yarn consumption rate through the velocity sensor and autonomously adjusting the drum rotation speed via the control unit. This self-regulating mechanism maintains precise consumption control without requiring manual intervention or complex operational procedures from the operator, thus preserving ease of operation while improving manufacturing precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for economic and practical control of yarn consumption rate on existing machines, preventing defects and ensuring repeatability in garment size by dynamically adjusting tension based on measured consumption rates, particularly in constant consumption steps.
Implementation Method 1
a velocity sensor adapted to measure a consumption rate of the yarn
Implementation Method 2
continuously comparing the consumption rate with a desired consumption rate, if a difference between the measured consumption rate and the desired consumption rate falls within a predefined error range, then adjust the reference tension so as to minimize the difference between the measured consumption rate and the desired consumption rate
Data Source
Figure 1
AI summary
The yarn tension is stabilized on a reference tension (T_ref) by a weft braking device (20) driven by a control unit (CU) that receives a measured tension signal (T_meas) from a tension sensor (22). The yarn consumption rate (YS_meas) is continuously measured and is continuously compared with a reference rate (YS_ref). If the difference between the yarn consumption rate (YS_meas) and the reference rate (YS_ref) falls within a predefined error range that indicates that the machine is operating with constant consumption, then adjust the reference tension (T_ref) so as to minimize the difference between the yarn consumption rate (YS_meas) and the reference rate (YS_ref), otherwise disable the adjustment of the reference tension (T_ref).