Air Jet Loom Weft Yarn Arrival Timing Control
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Solution Overview
Problem
Existing methods for controlling weft insertion in air jet looms using feed-forward control require complex calculations due to variations in weft yarn type and air pressure, leading to potential timing deviations that complicate the process.
Innovation Solution
A method that modifies the lifting timing of a holding pin in response to deviations between predicted and target weft yarn arrival timings, simplifying calculations by decoupling the lifting timing from transfer speed influences, thereby correcting arrival timing without affecting the transfer speed of the weft yarn.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the duration of opening of the nozzle or air pressure is modified as control parameters, then the weft yarn arrival timing can be adjusted, but the calculation complexity increases due to varying transfer speeds depending on weft yarn type and air pressure
Solution Approach 1:
The patent extracts the holding pin lifting operation from the transfer speed control parameters. By modifying only the holding pin lifting timing rather than adjusting nozzle duration or air pressure, the system decouples the timing correction from the complex transfer speed calculations that vary with weft yarn type and air pressure conditions
Solution Approach 2:
The control process is segmented into two independent parts: transfer speed control (determined by nozzle parameters) and arrival timing control (determined by holding pin lifting timing). This segmentation allows each parameter to be optimized independently, simplifying the overall control calculation
2Manufacturing precision
If the nozzle opening duration or air pressure is changed to correct arrival timing deviation, then the weft insertion timing accuracy improves, but the transfer speed of weft yarn is inadvertently altered
Solution Approach 1:
The patent separates the control of transfer speed and arrival timing into independent parameters. The nozzle opening duration and air pressure control transfer speed, while the holding pin lifting timing controls arrival timing. This segmentation ensures that correcting arrival timing does not inadvertently alter transfer speed
Solution Approach 2:
The holding pin lifting timing acts as an intermediary control parameter that directly influences arrival timing without affecting transfer speed. By using this intermediate control point, the system can correct timing deviations independently of the transfer speed parameters
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 approach simplifies the weft insertion control calculations and ensures accurate timing without altering the transfer speed, allowing for consistent performance across different weft yarn types.
Implementation Method 1
a weft yarn characteristics detection unit configured to detect a characteristic of the weft yarn
Data Source
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AI summary
A method of controlling weft insertion of an air jet loom that includes a holding pin (17) configured to hold and release a weft yarn (11), and a weft insertion nozzle (6, 7, 8) that injects air is provided. The method includes the steps of: detecting a characteristic of the weft yarn (11) that is yet to be inserted; predicting a weft yarn arrival timing at which the weft yarn (11) inserted in accordance with a specified weft insertion condition arrives at a specified position in a weft insertion direction, on the basis of the detected characteristic of the weft yarn (11); determining a difference between the predicted weft yarn arrival timing (TWp) and a target weft yarn arrival timing (TWr); modifying a lifting timing of the holding pin (17) in accordance with the determined difference; and lifting the holding pin (17) at the modified lifting timing to insert the weft yarn (11).