EP2207922A1

EP2207922A1 - Thread delivery device with an adaptive regulator

Info

Publication number: EP2207922A1
Application number: EP07819283A
Authority: EP
Inventors: Rolf Huss; Norbert Bammert
Original assignee: Memminger IRO GmbH
Current assignee: Memminger IRO GmbH
Priority date: 2007-10-24
Filing date: 2007-10-24
Publication date: 2010-07-21
Anticipated expiration: 2027-10-24
Also published as: EP2207922B1; TWI427202B; TW200940768A; CN101849056A; WO2009052846A1; CN101849056B

Abstract

A thread delivery apparatus (1) for tension-regulated thread feeding has an adaptive regulator for controlling its drive motor (7). The adaptive regulator controls the drive motor (7) according to the thread tension which is detected by means of a thread tension sensor (12). A calibrating module (16) is provided for determining the compliance of the thread (2) in a test and for fixing the regulating parameters of the regulator correspondingly. This relates, in particular, to the D proportion of the regulator, but can also relate to the P proportion and/or the Ü proportion. The thread delivery apparatus is therefore adapted automatically to different use conditions.

Description

Yarn feeding device with adaptive controller

The invention relates to a yarn feeding device for supplying at least one thread to a yarn consumption point. In particular, the invention relates to a yarn feeding device for live yarn delivery.

Yarn feeding devices for live yarn delivery are known. For example, EP 0943713 A2 discloses such a device. It has a yarn feed wheel, which is driven by an electric motor. The thread wraps around the yarn feed wheel one or more times and then runs over a yarn tension sensor to the yarn consumption point. The thread tension sensor is associated with a lift-off device to lift the thread from time to time from the sensor. As a result, the thread tension sensor is relieved and a zero point adjustment can be made.

The yarn feeding device serves to supply the yarn with substantially constant tension to the yarn consumption point. For this purpose, the electric motor and the thread tension sensor are connected to each other via a control loop.

The removal of the yarn feeding device from the yarn consumption point and the thread properties can influence the function of the control loop positively or negatively. This can lead to practical difficulties.

On this basis, it is an object of the invention to provide a yarn feeding device, which is largely independent of the nature of the threads to be supplied as well as possible independent of the mounting position of the yarn feeding device, especially in terms of its distance from the yarn consumption point works reliably.

This object is achieved with the yarn feeding device according to claim 1:

The yarn feeding device according to the invention has a motor-driven Fadenlieferrad which is adapted to convey the thread. In the yarn path a yarn tension sensor is arranged, which detects the yarn tension and supplies a yarn tension signal to a control device. The drive device controls the motor so that thread tension fluctuations are counteracted. The yarn delivery device according to the invention contains an adjustment module. This is adapted to detect the compliance of the thread. Preferably, the drive means is adjusted based on the detected thread tension so that the operation of the motor will meet the characteristics of the yarn to be supplied. In other words, the control device adapts its operation to the flexibility of the thread determined by the adjustment module.

It can vary the recorded thread hardnesses or compliance in a wide range. For example, very hard threads have a spring coefficient of more than 10,000 cN / m. By contrast, very soft threads have a spring constant of less than 100 cN / m. It is possible and preferred here to classify the threads to be delivered into several, for example four, compliance classes. These four classes may be, for example, classes which typically include elastane (up to 100 cN / m), medium hard filaments (100 to 1000 cN / m), hard filaments such as cotton (1000 to 10,000 cN / m) and very hard filaments (eg more than 10,000 cN / m). The adjustment module detects the actual thread tension and then selects, for example, one of the four classes mentioned for setting the activation device. The yarn feeding device can then be operated with this selected setting until a new adjustment takes place.

It is possible to cause the determination of the thread property by means of the adjustment module by an external signal. Such a signal may be, for example, a keystroke of an operator on a corresponding control button, a trim signal obtained via a wired or non-wired network, or a start signal provided by a central machine controller of a knitting machine. Further modifications are possible. In this case, for example, the operator places a thread on the yarn feeding device and then actuates a corresponding acknowledgment button, whereupon the yarn feeding device determines the thread tension and after this process goes into normal operation. The completion of the determination of the yarn hardness can be provided by an acknowledgment signal to the central control of the knitting machine to release it.

It is also possible that the adjustment module makes the determination of the thread hardness or the flexibility of the thread independently from time to time. Such compliance tests can be carried out, for example, in phases in which the yarn delivery wheel is in spite of running knitting machine or other thread-consuming machine. For patterned fabrics, this happens from time to time when the thread in question is not needed. This procedure has the advantage that the yarn feeding device works independently, without the need for an operator or other parts of the control system to ensure that a calibration is carried out. will be.

The yarn feeding device has, for example, a rotary encoder connected to the motor or the yarn feeding device, which detects the rotational position of the yarn feeding wheel. Preferably, a rotary encoder is used here, which detects a high resolution of, for example, 360 increments per revolution of the yarn feed wheel. In the preferred embodiment, the encoder has a resolution of 800 increments per revolution. To determine the compliance of the thread, the yarn delivery wheel is rotated in an idle phase, in which it should in itself be in a given angular position, by an angular amount, in order to consciously change the thread tension. The rotation of the yarn feed wheel can take place both in the sense of an increase in the thread tension and in the sense of a reduction in the thread tension, which is preferred. The thread tension can be reduced to zero, whereby on the one hand not linear spring characteristics of the thread can be detected and on the other hand, a zero point adjustment of the yarn tension sensor is possible. On the other hand, the increase of the thread tension for test purposes has the advantage that a drop of turns from the yarn feed wheel is safely excluded. If the yarn hardness determined by increasing the thread tension (reverse rotation of the yarn feed wheel) is preferably only a small angle of rotation of the yarn feed used. In addition, it may be advantageous to arrange a yarn store in front of the yarn feed wheel, which receives the thread section delivered back by the reverse rotation of the yarn feed wheel.

It is possible to perform the thread tension test with a constant travel of the motor. It is then detected the incoming thread tension change. However, it is also possible to generate a predetermined voltage change (for example voltage change on a given voltage). value or zero) and to track the required rotation angle of the motor. Both tests provide information about the compliance of the thread.

Preferably, the spring action of the thread between Fadenlieferrad and yarn consumption point is determined. This value depends on the thread properties and the length of the thread running path and thus characterizes the total elasticity of the thread. The control device is preferably a control loop with a controller which has at least one P component (proportionately amplifying component) and at least preferably also one D component (differentiating component). The magnitude of the amplification of the P component as well as the amplification of the D component, as well as its frequency at which it takes effect and its time constant are parameters of the control loop. These parameters are tuned by the balancing module on the properties of the thread in particular its compliance. Thus, the yarn feeding device automatically sets the parameters of its control loop with respect to the compliance of the yarn to be supplied.

Alternatively it can be provided that the adjustment module determines the thread compliance empirically. For this purpose, it may be provided that the controller initially works with parameters that are to be applied to frequently used threads. If the parameters are specified, for example, for several thread compliance classes, you can initially work with a class that is frequently used. From the resulting temporary control deviations, ie from the dynamic behavior of the controller can then be determined whether to work with a matching class, or whether the class should be changed. Accordingly, the controller can automatically reset its control parameters after a short (trial) operating time. This can be done without separate adjustment Procedure done during operation. With sufficiently fine graduation of the classes can be optimized in this way the operation of the controller, ie the control quality.

Further details of advantageous embodiments of the invention are the subject of the description, the drawings or claims. The description is limited to essential aspects of the invention and other circumstances. The drawing is complementary and reveals more details. Show it:

1 shows a yarn feeding device with control loop in a schematic representation,

FIG. 2 is a schematic representation of the regulator of the yarn feeding device according to FIG. 1,

Figure 3 transmission functions of the controller of Figure 2 in a schematic representation and

Figure 4 shows different spring characteristics of threads that can deliver the yarn feeding device of Figure 1.

FIG. 1 shows a yarn delivery device 1. represents, which may be part of a larger system or as a separate yarn feeding device. The yarn feeding device 1 serves to supply a yarn 2 from a suitable source, such as a large bobbin, to a yarn consumption point 3 formed, for example, by needles 4 of a knitting machine. The thread 2 is the Fadenverbrauchsstelle 3 supplied with controlled voltage. Serves a yarn feed wheel 5, which is engaged with the yarn 2. For example, it is wrapped one or more times by the thread 2 in order to draw the thread 2 from the thread source, optionally through a thread brake 6, and to deliver it to the thread consumption point 3.

The yarn feed wheel 5 is driven by a motor 7. This can be designed as a DC motor, as a stepping motor, pancake motor or the like. Its output shaft 8 carries the yarn feed wheel 5. The motor 7 is connected via a plurality of lines 9, which are illustrated schematically in Figure 1, with a drive means 10. If the motor 7 is a stepper motor, the rotational position of the wear shaft 8 and the yarn feed wheel 5 is given by the step pulses supplied by the drive device 10. Thus, a corresponding memory register can be provided in the control device 10, which contains a value characterizing the rotational position of the yarn feed wheel 5, for example in the form of digital data.

If the motor 7 is an otherwise motor, for example a DC motor, the motor 7 may be connected to a position sensor 11, which detects the rotational position of the output shaft 8, preferably with high resolution of, for example, more than 360 pulses per revolution. This position sensor 11 can also with the yarn feed wheel 5 cooperate to detect the rotational position directly.

Between the yarn consumption point 3 and the yarn feed wheel 5, a yarn tension sensor 12 is provided. This one has e.g. two thread guiding elements, e.g. in the form of pins 13, 14, between which a pin 14 connected to a force transducer is connected. The force transducer (not further illustrated) forms the actual sensor which generates the electrical sensor output signal of the yarn tension sensor 12. This output signal is passed to a comparator stage 15, which compares the thread tension actual value with the thread tension setpoint value and generates a difference signal therefrom. This is supplied to the drive device 10 which controls the motor 7 based on the deviation or error signal in order to minimize the error signal.

The sensor output signal is also supplied to an adjustment module 16, which can influence the drive device 10. For this purpose, several active compounds 17 are entered in FIG. The active compounds serve to set parameters of the control device 10 and to trigger a calibration mode. This can be carried out internally, for example, time-controlled or state-controlled, for example after detection of a prolonged inactivity of the electric motor 7 or by a pulse to an input 18 of the balancing module 16 and / or the control device 10.

The control device 10 is formed for example as a regulator. This receives at its input 19 from the comparator stage 15, the error signal representing the deviation between the actual value of the thread tension and the desired value. The signal is sent to three parallel mo- delivered in hardware or software _. can be. The three modules 20, 21, 22 represent different "parts" of the controller 10. The module 20 represents an I component of the controller. The I component is an integrating component, its transfer characteristic, ie the ratio of its output signal to the input signal via The frequency ω is illustrated as a falling straight line in Figure 3. The I component of the control device 10 eliminates the permanent control deviation.

Between the control device 10 and the motor 7, a position control loop or a speed control circuit can be arranged. The drive circuit then specifies a desired yarn wheel angular position as a function of time or a desired yarn wheel speed. The position or speed control circuit then controls the motor 7 accordingly so that the desired angular position or the desired speed can be set.

The module 21 represents the proportional portion of the driver 10. Its transfer characteristic is illustrated in FIG. 3 by a horizontal straight portion.

The module 22 represents the differentiating component (D component) of the controller of the drive device 10. The D component forms a transfer characteristic with an increasing straight line, as illustrated in FIG.

The slopes and positions of the straight lines of the I component and the D component and the gain of the P component represent parameters of the controller of the control device 10.

The controller can use other eg non-linear blocks or Contain functional groups. For example, the controller can be connected to an observer who draws conclusions from his reactions and, if necessary, adjusts controller parameters. The observer can also be part of the adjustment module 16.

The thread located between the yarn feed wheel 5 and the yarn consumption point 3 can be regarded as a spring. Depending on the yarn hardness, it has a large or a small change in the tensile force F with a corresponding change in length X. This is shown in FIG. 4 at different yarn characteristics 23, 24, 25, 26. These characteristics 23 to 26 may be linear or non-linear - depending on the type of thread.

The yarn feeding device 1 described so far operates as follows:

It is initially assumed that the parameters of the controller of the control device 10 are fixed and that the comparator stage 15 is supplied to a setpoint value for the thread tension. The yarn sensor 12 detects the yarn tension and reports this to the comparator stage 15. The control device 10 controls the motor 7 in such a way that the desired yarn tension on the sensor device 12 is set. This applies to both stationary and running thread. If, for example, the yarn consumption point picks up 3 threads and this thread take-off tends to increase the thread tension, the activation device 10 sets a corresponding engine speed of the motor 7, so that the supplied amount of thread corresponds to the requirement. If the thread requirement increases, which would lead to an increase in the thread tension at a constant engine speed, the drive device 10 increases the engine speed, so that the yarn delivery also increases. The reverse applies when reducing the thread consumption. The driver 10 can adequately respond to rapid changes in yarn consumption. This is particularly due to the module 22 with the D portion of the controller. If, for example, a sudden change in the thread requirement is noted, this initially leads to a temporary thread tension deviation, ie a difference between the thread actual tension and the thread set tension. The D component of the controller amplifies these short-term changes particularly strong and thus leads to an accelerated acceleration of the motor. 7

In particular, the size of the D component, ie its parameters, are variable. The control device 10 can thus be adjusted with respect to the slope and / or the frequency ω, from which the D component is effective. If, for example, according to FIG. 3, the D component is normally effective as of a frequency of ω _x , the D component can be adjusted such that it already becomes effective at a lower or even at a higher frequency ω ₂ . In addition, the slope of the D component in the transmission diagram of Figure 3 can be adjusted. The D component can thus be adjusted with regard to at least one parameter, but preferably also with regard to two or more parameters. The adjustment takes place on the basis of the yielding of the thread determined by the adjustment module 16, ie on the basis of the characteristic of the controlled system. For this, the active compounds 17 are provided.

In detail, the adjustment of the controller can be done in a setting mode in which, for example, the motor 7 is not running. For example, the adjustment module 16 detects this idle state. Alternatively, it may also be activated by a pulse at its input 18. The balancing module 16 now indicates a command via the operative connection 17 This controls the motor 7 now, for example, so that the yarn feed wheel 5 rotates in the conveying direction. The angle of rotation of the yarn feed wheel is detected either via counted drive step pulses supplied to the motor 7 or based on a signal from the angle sensor 11. This is then connected via a not further illustrated signal transmission line to the balancing module 16. The adjustment module 16 now allows the motor 7 to rotate while monitoring the thread tension by means of the sensor 12 until the thread tension has reached a reduced value of, for example, zero. The angle traveled by the yarn feed wheel 5 corresponds to a change in length of the yarn 2. The experienced force change, when set in relation to the change in length, results in the steepness of the yarn characteristic. Thus, the linear spring coefficient of the thread is determined. This works well for threadlines such as the curves 23, 24 in FIG. 4. They represent straight lines through the zero point of the Fx diagram.

In the case of nonlinear characteristics such as characteristic curves 25 or 26, this method will lead to different notions of the characteristic depending on whether the starting point 27 or the starting point 28 for the thread tension has been started. These are dotted registered.

However, these characteristics approximate the behavior of the thread relatively well and can therefore be used as the basis for further adjustment of the controller.

If, on the other hand, the thread tension is not lowered to zero as described above, but rather to a value other than zero, the gradient of the Characteristic 25 or 26 determined in the vicinity of the thread tension with which the thread is to be delivered. The control parameters can then be determined based on this value of compliance. The yielding thus determined is also called differential compliance.

If the thread tension is reduced to zero during adjustment, the zero point of the thread tension can be recognized by the fact that the signal delivered by the thread tension sensor 12 no longer reduces despite (slight) further rotation of the thread feed wheel 5. The yarn feed wheel 5 is then stopped and a zero adjustment of the yarn tension sensor can be made.

It has proven to be expedient if the balancing module 16 classifies the detected resilience of the thread into classes, for example four classes K1, K2, K3 and K4. The threads with the characteristic curves 23 and 24 are independent of the measuring method and starting point of the measurement in the classes K1 and K3. The thread with the characteristic curve 25 can be sorted into the class K3 or K4 depending on the starting point 27 or 28. In particular, if the "small-signal behavior", ie the dynamic or differential thread compliance, is sufficient, a small variation of the thread tension is sufficient to determine the compliance, in which case the thread 25 is class K. The thread with the non-linear characteristic curve 26 is clearly in the Class K4, however, if it is supplied in a strongly tensioned state, ie if the operating point lies in its right steeply increasing characteristic part, the measurement of the thread hardness results in the membership of the classes K2 or K3.

The balancing module 16 can determine for each of the predefined classes the suitable parameters for the controller of the control system. Keep the device 10 ready and transmit it to the controller once the thread has been determined. The controller then works with a relatively well adapted to the thread, ie the controlled system control characteristics.

A yarn feeding device 1 for tension-controlled yarn feeding has an adaptive controller for controlling its drive motor 7. The adaptive controller controls the drive motor 7 according to the detected by means of a yarn tension sensor 12 thread tension. An adjustment module 16 is provided to determine in a test, the compliance of the thread 2 and set the control parameters of the controller accordingly. This concerns in particular the D-portion of the controller but can also affect the P-portion and / or the Ü-portion. The yarn feeding device thus adapts automatically to different operating conditions.

Reference number:

1 thread delivery device

2 threads

3 thread consumables

4 needles

5 thread feed wheel

6 thread brake

7 engine

8 output shaft

9 lines

10 drive device

10 'controller

11 angle encoder

12 thread tension sensor

13, 14 pens

15 grade level

16 adjustment module

17 active compound

18, 19 entrance

20, 21, 22 module

23, 24, 25, 26 characteristics

27, 28 starting points

Claims

Claims:

1. Yarn feeding device (1) for supplying a thread

(2) to a thread consumption point (3),

a yarn feed wheel (5) engaged with a yarn (2) to convey it,

with a motor (7) which is connected to the yarn feed wheel (5) in order to drive it in rotation,

with a drive device (10) which is connected to the motor (7) in order to supply it in a controlled manner with operating current,

a yarn tension sensor (12) connected to the drive means (10) for supplying a yarn tension signal thereto;

wherein the drive device (10) is adapted to control the motor (7) controlled by the thread tension, and

wherein the drive means (10) comprises an adjustment module (16) adapted to determine the compliance of the thread (2).

Second yarn feeding device according to claim, comprising a rotary encoder (11) which is connected to the motor (7) or the yarn feed wheel (5) to detect its rotational position and which is connected to the drive means (10) to a rotational position signal to deliver these.

3. Yarn feeding device according to claim 1, wherein the drive means (10) comprises a regulator (10 ').

4. Yarn feeding device according to claim 3, wherein the controller (10 ') has a frequency-independently proportional proportion (P).

5. Yarn feeding device according to claim 4, wherein the controller (10 ') additionally has a differentiating component

(D).

6. Yarn feeding device according to claim 5, wherein the controller (10 ') additionally an integrating portion

(I).

7. Yarn feeding device according to claim 3, wherein the controller (10 ') has parameters that are adjustable.

8. Yarn feeding device according to claim 7, wherein the parameters are adjustable by the balancing module.

9. Yarn feeding device according to claim 1, wherein the adjustment module (16) for determining the compliance of the thread (2) causes the motor (7) to perform an adjusting movement for changing the thread tension, wherein the travel of the motor (7) is detected.

10. Yarn feeding device according to claim 9, wherein the thread tension is reduced to zero, in addition to determining the compliance of the thread (2) carry out a zero adjustment of the sensor device (12).