Yarn Feed Control System for Low-Speed Tension Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing yarn or metal wire feed devices, particularly those using brushless motors, face challenges in controlling tension and speed at low speeds due to poor braking action, leading to undesirable dragging of the drive shaft and inability to maintain precise yarn feed tension.
Innovation Solution
A control system that continuously measures the angular position of the drive shaft using an encoder, compares it with predetermined parameters, and feeds command signals to the actuator to maintain desired yarn characteristics, such as tension, speed, and torque, independent of external stresses, using PID controllers and an inverter with vectorial piloting to optimize motor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a brushless motor is used to drive the yarn feed device, then the motor provides considerable accelerating action and high power, but the braking action is poor at low speeds causing the drive shaft to be dragged into rotation undesirably
Solution Approach 1:
The system uses a tension sensor to continuously measure yarn tension and feeds this information back to a PID tension controller, which compares the measured tension with a reference signal and adjusts the motor command signals accordingly to maintain desired yarn feed tension
Solution Approach 2:
The system changes the control parameters by using PID (proportional-integral-derivative) control instead of simple speed control, allowing the motor to maintain precise tension control across varying speeds by dynamically adjusting motor output based on tension feedback
2Speed
If the actuator rotational speed is reduced to control yarn tension, then the yarn feed speed decreases, but the braking torque becomes insufficient allowing external traction to drag the drive shaft
Solution Approach 1:
The system transitions from speed-only control to tension-based PID control, changing the control parameter from rotational speed to yarn tension, enabling the actuator to maintain adequate braking torque even at low speeds by responding to tension feedback rather than speed commands
Solution Approach 2:
The tension sensor provides continuous feedback on yarn tension, allowing the control system to detect when external traction is dragging the drive shaft and immediately adjust motor output to compensate, maintaining control authority across the full speed range
3Reliability
If a PID tension controller is used to maintain yarn tension, then tension control is improved, but the system cannot operate independently without interface or synchronism with the textile machine
Solution Approach 1:
The system is designed with dual capability: it can operate independently using tension sensor feedback and PID control, or it can interface with textile machine synchronism systems when required, making it universally applicable to different machine configurations
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 control of yarn feed characteristics, minimizing torque ripple and ensuring optimal yarn tension and speed regulation at low motor speeds, preventing drive shaft dragging and achieving high precision and efficiency in yarn feeding.
Implementation Method 1
means 4 for continuously measuring an angular position of the drive shaft of the actuator 2, for example by means of an encoder
Implementation Method 2
the actuators of known type, in particular brushless motors, have a considerable accelerating action but poor braking action
Data Source
Figure 1~3
Figure 4~6
AI summary
A system (1) for controlling the feed of a yarn to a textile machine or a metal wire to a coil winder or a similar machine, the yarn or wire unwinding from its own spool and cooperating with a rotary member associated with its own rotation actuator (2) before being directed to the machine, the yarn or wire having its own characteristic value of tension and/or speed and/or quantity during this feed, the rotation actuator (2) comprising a stator and a rotor acting on an exit drive shaft (13) and being piloted by its own piloting means, the rotary member about which the yarn or wire winds being keyed onto the exit drive shaft (13), the control system comprising: - means (4) for continuously measuring an angular position of the drive shaft of the actuator (2), - comparison and command means (5, 8) connected downstream of the measurement means (4), to compare an instantaneous parameter correlated to the measured angular position of the drive shaft (13), with a corresponding predetermined parameter relative to a prefixed characteristic value of the yarn or wire, and to feed command signals to piloting means (3, 6) for the actuator (2) such that the instantaneous parameter conforms to the predetermined parameter, so as to obtain the required characteristic value of the yarn or wire fed to the machine.