Traversing Unit Controller With Dual QEP Evaluation Units
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Solution Overview
Problem
Existing traversing units for guiding threads during bobbin winding face challenges in precision and speed control, particularly at the ends of the traversing stroke, leading to deviations from target positions and speeds, which results in uneven thread windings and increased breakage.
Innovation Solution
A traversing unit with a controller utilizing two QEP evaluation units with different clock frequencies for generating data streams, coupled with a signal processing unit and optocoupler, allows for precise control of the thread guide by differentiating angular velocity and ensuring accurate positioning and movement, especially in reversal areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single QEP evaluation unit with fixed clock frequency is used, then the device complexity is reduced, but the manufacturing precision deteriorates due to inability to adapt to different angular velocities
Solution Approach 1:
The system dynamically switches between two QEP evaluation units with different clock frequencies based on the angular velocity of the drive shaft. During reversal phases with low angular velocity, the first QEP evaluation unit with higher clock frequency provides high-resolution measurement. During linear motion with high angular velocity, the second QEP evaluation unit with lower clock frequency is used, preventing erroneous reactions while maintaining adequate measurement capability.
Solution Approach 2:
The control device is segmented into two parallel QEP evaluation units, each optimized for different operating conditions. The first evaluation unit handles low-speed reversal phases with higher measurement resolution, while the second handles high-speed linear motion. A selection mechanism chooses which evaluation unit's data stream to use based on current operational phase, effectively dividing the measurement task into specialized sub-tasks.
2Productivity
If the thread guide moves quickly through the changing stroke, then the productivity is improved, but the manufacturing precision deteriorates due to insufficient control accuracy at reversal points
Solution Approach 1:
The control system dynamically adapts its measurement resolution to the operational phase. During high-speed linear motion, the lower clock frequency of the second QEP evaluation unit prevents erroneous reactions while maintaining adequate control. During critical reversal phases, the system switches to the first QEP evaluation unit with higher clock frequency, ensuring precise control and accurate thread placement even though these phases occupy less time in the overall cycle.
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 enables precise and efficient thread winding with reduced errors, ensuring that thread windings are deposited uniformly on the bobbin, enhancing the usability of the spool for further mechanical processing.
Implementation Method 1
coupled with a signal processing unit and optocoupler
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The invention relates to a traversing unit for guiding a thread and to a method for controlling such a traversing unit. The traversing unit has a motor (170) with a driveshaft (171) for driving a thread guide (120), said motor being connected to a controller (330). The controller is connected to an incremental encoder (180) which is coupled to the driveshaft of the motor. The aim of the invention is to allow an analysis of the incremental angle signals of the incremental encoder dependent on the guiding speed of the thread guide. According to the invention, this is achieved in that the controller has a first QEP analysis unit (320-1) for generating a first data stream and a second QEP analysis unit (320-2) for simultaneously generating a second data stream.