Method and device for operating a creel designed for a winding system and corresponding creel
The invention concerns a creel ( 2 ) comprising a plurality of winding heads ( 7 ) from which several yarns of the same type or of different types are drawn simultaneously by means of a winding machine ( 3 ). Said creel comprises at least one dynamic yarn tension device ( 6 ) which is associated with each winding head and at which a variable braking force is applied to the yarn to produce a predetermined yarn tension. Each yarn tension device ( 6 ) can be activated by means of an associated drive motor ( 20 ). Said creel ( 2 ) comprises a control device for controlling the yarn tension based on the angular speed or the yarn speed during a start-up and/or an interruption of the winding machine ( 3 ), as well as a regulator ( 25 ) for regulating the yarn tension during the normal stationary phase of the winding machine ( 3 ). The control device and the regulator ( 25 ) are designed such that the yarn tension or the output tension of each yarn can be maintained at a substantially constant level relative to a setpoint value. In order to determine a quantity of regulation ( 32 ) of the braking force required to control the yarn tension device ( 6 ), a precompensation of the disturbing quantity is implemented. Said precompensation calculates from the yarn speed (v) as input quantity a compensated correction quantity ( 34 ) of at least the inertia of the motor and a friction coefficient of the drive motor ( 20 ).
1. A method for operating a creel for a winding system having a plurality of bobbin stations, in which method a plurality of threads are taken up from the bobbin stations jointly by means of a winding machine rotating at an angular speed, the thread being acted upon with a variable braking force at each bobbin station with the aid of at least one thread tensioner in order to generate a specific thread pull, the thread tensioner being activated by a drive motor wherein, during a run-up operation and/or a stopping operation of the winding machine, each thread tensioner is controlled via the angular speed of the winding machine, in order to keep the thread pull of each thread approximately constant with respect to a desired value.
2. The method as claimed in claim 1 , wherein the angular speed of the winding machine is measured continuously during the run-up operation and/or the stopping operation and is converted into a thread speed, each thread tensioner being controlled by means of the thread speed as an input variable for the control.
3. The method as claimed in claim 1 , wherein a braking force for controlling the thread tensioner is calculated from thread speed and parameters of the drive motor of the thread tensioner.
4. The method as claimed in claim 1 , wherein, to determine a manipulated variable for a braking force for controlling the thread tensioner, a disturbance variable compensation, with thread speed as an input variable, calculates a correcting variable.
5. The method as claimed in claim 1 , wherein, to determine a manipulated variable for a braking force for controlling the thread tensioner, a disturbance variable compensation, with thread speed as the input variable, calculates a correcting variable compensated by at least the motor inertia and the coefficient of friction of the drive motor.
6. The method as claimed in claim 1 , wherein, during steady-state operation of the winding machine, the actual value of the thread pull of each thread is detected continuously by a thread tension sensor and is regulated to the desired value by means of a controller.
7. A device for operating a creel for a winding system with a creel having a plurality of bobbin stations and with a winding machine for the joint winding of a plurality of threads of which are taken up from the bobbin stations, for maintaining a constant thread pull of each thread, wherein the device has a disturbance variable compensation for controlling the thread pull during the run-up operation and/or the stopping operation of the winding machine, which is operatively connected on an input side to a rotary encoder of the winding machine, by means of which rotary encoder a signal for the angular speed of the winding machine can be generated.
8. The device as claimed in claim 7 , wherein a speed measurement device is provided, by means of which thread speed can be measured on the basis of the angular speed of the winding machine.
9. The device as claimed in claim 7 , further comprising a controller for regulating the thread pull during steady-state operation of the winding machine is provided.
10. The device as claimed in claim 7 , further comprising a summing device for generating a manipulated variable representing a braking force necessary for controlling the thread tensioner which summing device adds a correcting variable output by the disturbance variable compensation to a desired variable for the braking force of the thread tensioner.
11. A creel having a plurality of bobbin stations, from which a plurality of threads can be taken up simultaneously by means of a winding machine, and having at least one dynamic thread tensioner which is assigned to each bobbin station and which the thread can be acted upon with a variable braking force in order to generate a specific thread pull, each thread tensioner being activatable by means of a respective drive motor further comprising a control device for controlling thread pull as a function of angular speed or thread speed during a run-up operation and/or a stopping operation of the winding machine and a controller for regulating thread pull during steady-state operation, the control device and the controller being configured in such a way that thread pull or initial thread tension of each thread can be kept approximately constant with respect to a desired value.
12. The creel as claimed in claim 11 wherein each thread tensioner has in each case at least one rotatable rotary body with an axis of rotation, the thread engaging at least partially on the circumferential region of the rotary body for action by a braking force and the rotary body can be driven via the respective drive motor in order to set the braking.
13. The creel as claimed in claim 12 , wherein the thread is wound at least once around said rotary body.