Warp Yarn Tension Control Through Dragging-Roller Torque
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Solution Overview
Problem
Existing textile machines lack an efficient and cost-effective method for accurately controlling warp yarn tension during operation, particularly in the absence of load cells and dancer rollers, leading to potential defects in the textile product.
Innovation Solution
The method employs the detection of drag torque on the dragging roller to adjust the tension of warp yarns by monitoring the supply current of the drag motor, using a central processing unit to maintain a target tension through a braking system, eliminating the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional tension control systems using load cells and dancer rollers are employed, then measurement precision of warp yarn tension is improved, but device complexity and cost increase
Solution Approach 1:
The invention extracts the tension measurement function from separate sensors (load cells, dancer rollers) and integrates it into the existing drag motor system. The drag torque detector already present in the system is repurposed to detect warp yarn tension through the relationship between drag torque and tension, eliminating the need for additional measurement devices.
Solution Approach 2:
The drag motor and its torque detection system serve dual functions: maintaining fabric tension during weaving and measuring warp yarn tension. By controlling the drag motor to maintain constant drag torque, the system simultaneously performs mechanical work and provides accurate tension measurement without requiring dedicated measurement components.
2Device complexity
If drag torque detection method is used to control warp yarn tension, then device complexity is reduced by eliminating sensors, but measurement precision may be compromised
Solution Approach 1:
The system employs feedback control by continuously monitoring drag torque and adjusting the drag motor operation accordingly. The drag torque detector provides real-time feedback on the tension state, and the control system modifies the drag motor's torque output to maintain the desired tension level, ensuring both simplicity and precision.
Solution Approach 2:
The invention replaces complex mechanical measurement systems (load cells, dancer rollers) with an electrical control system that uses the existing drag motor and torque detector. The relationship between drag torque and warp yarn tension is exploited to substitute mechanical measurement with electrical sensing and control.
3Productivity
If supply motors are used to positively rotate supply units, then productivity is improved by ensuring continuous yarn supply, but device complexity and cost increase
Solution Approach 1:
The invention merges the supply motor function with the drag motor system. The same drag motor that controls fabric tension also drives the supply reels to unwind warp yarns. By integrating these functions, the system achieves continuous yarn supply without requiring separate supply motors, thereby maintaining productivity while reducing device complexity.
Solution Approach 2:
The drag motor system serves multiple purposes including driving the supply reels, maintaining fabric tension, and providing tension measurement. The system is designed so that the drag motor's rotation and torque control inherently manage the yarn supply process, eliminating the need for additional dedicated supply mechanisms.
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 ensures precise and reliable tension control of warp yarns, maintaining consistent tension throughout the weaving process, thereby enhancing product quality and simplifying the construction of the textile machine.
Implementation Method 1
The drag motor is a known electric motor which is capable of submitting the dragging roller to a controlled drag torque
Implementation Method 2
a brake is provided which is capable of being acted upon by the central processing unit, to increase and/or decrease the braking action exerted on the warp yarns
Data Source
Figure 1
Figure 2
AI summary
Warp yarns (3) unwound from a supply unit (2) moves to reach a yarns-interlacing area (5), wherein a textile product (6) is formed. A dragging roller (8) advances the textile product (6) away from the yarns-interlacing area (5), keeping a selected target advancement speed Vtv. A braking action is achieved on the warp yarns (3) upstream of the dragging roller (8), to provide a supply traction force SF along the warp yarns (3). Monitoring of the supply traction force is achieved based on an instant value DT of a drag torque applied by the dragging roller (8). A target value SFtv of the supply traction force is kept during operation of the textile machine (1) by repeated control cycles, each comparing the instant value DT with a target value DTtv of the drag torque, corresponding to said target value SFtv of the supply traction force. The braking action is modulated to keep the supply traction force SF at the target value SFtv.