EP0617149B1 - Method for evening textile fibre bands - Google Patents

Description

The invention relates to a method for homogenizing textile fiber tapes in a draw frame with tape feed rollers and tape discharge rollers according to the preamble of claim 1.

DE 23 31 217 A1 discloses a device for uniformizing the thickness of fiber slivers, in which the fluctuations in mass of the fiber slivers are detected cyclically by a measuring device.

The cyclically determined measured values are entered one after the other into storage locations in an electrical store (capacitor store) and, after a predetermined runtime, are fed out of phase as additional control variables to one of the drives in the region of the delay line.
The cycle or cycle time can be changed depending on the material speed.
The saved values are output in the same rhythm as the measured values are recorded and saved.
The basic size of the cycle time can be set using a mechanical gear.

With such a device, the manipulated value determined by a measured value can be realized when the measured section of the sliver is in the adjustable warping field.
The capacitor stores used here were unsatisfactory.

The device operates in a similar manner according to DE-Gbm 75 31 226.
In this device, the measured values are stored in a shift register in the cycle of their measurements and are pushed through the memory in the same cycle sequence.

The control values are output at the same frequency as the clock values.

The cycle sequence can be changed by an actuating gear, which varies the cycle time on the basis of the speed of the delay elements.

For the purpose of adapting the device to the processing of different fiber materials, the sliding register can be provided with several outputs. A mechanical switching element activates the output that offers the best conditions for the respective fiber material.

The disadvantage of this process is that the control signals are changed in direct dependence on the clock signal of the transmitter.

If you choose a very short cycle time, you get an exact image of the mass of the sliver with the measured values.

It has been shown that the motor is however not able to follow this necessarily large number of changed manipulated variables in the then very short time.
The motor movement becomes irregular and deviates from the specified target values as the machine's operating speed increases.
The sliver becomes or remains irregular.
The irregularities are only reduced insufficiently and distributed differently.

If, on the other hand, the cycle times for the acquisition of the measured values are longer, there is a risk that strongly deviating strip sections cannot be recorded at all and therefore cannot be corrected.

German patent 36 22 584 C2 describes a method and a device for regulating the warping of a sliver on a textile machine.
In the method proposed here, measured values from an encoder at the input of the drafting system and measured values at the output of the drafting system are alternately fed to a controller, temporarily stored and processed together to form a setpoint.

The setpoint thus formed is read into a shift register in time with the detection and is fed to the motor to be controlled with a time delay in the same cycle.

Such a way of working is complex and complicated. It also brings insufficient improvement in the uniformity of the sliver because the irregularities of the sliver detected at the end of the drafting system are not subject to a delay to be regulated again.

The disadvantages identified in connection with DE-Gbm 75 31 226 are also not eliminated with this method and this device.

DE 36 19 248 A1 essentially builds on the prior art just described.

With the aim of taking into account the parameters of the warping capability of the fiber slivers when outputting the manipulated variable, actuating means are proposed which are suitable for shifting the reaction point within the warpage zone or for changing the translation of the manipulated values.
Commonly used adjusting means are used for this purpose.

However, the basic problem described above is also not solved with this device.

• die im Faserband vorhandenen Ungleichmäßigkeiten möglichst vollständig zu beseitigen und
• das Entstehen neuer Ungleichmäßigkeiten durch die Trägheit des Reglers und seiner Stellmittel nach Möglichkeit vollständig auszuschalten.

Das gesuchte Verfahren soll durch bekannte und verfügbare technische Mittel realisierbar sein und dem Bedienpersonal die Möglichkeit geben, den Regler auf optimale Werte einzustellen.The object of the invention is to propose a method for equalizing textile fiber slivers in a drafting system, which is suitable

• to eliminate the irregularities in the sliver as completely as possible and
• if possible, completely eliminate the emergence of new irregularities due to the inertia of the controller and its adjusting means.

The method sought should be realizable by known and available technical means and should give the operating personnel the possibility of setting the controller to optimum values.

According to the invention, the stated object is achieved in a surprisingly simple manner by the method according to claim 1.

With the acquisition of absolute measured values, the problem of rechecking the warpage result is eliminated. The setpoint specified once at the start of the process is available as a measurement basis for each recorded ACTUAL value.

Another, but decisive, relief is the determination of average values from several measured values and the use of the average values to prepare a speed control value for the motor to be controlled.

The exact structure of the sliver is recorded for the control process, without having to carry out extremely fast adjustment processes with a large amplitude.

The storage of the measured value in a preferably electronic memory that can be managed by a processor also enables an average value or speed setpoint to be called up at any time to an optimized reaction point.

Practice has shown that the combination of these essential features of the method produces a sliver whose parameters come very close to the optimum.

The effort for the necessary device can be kept at a low level.
The use of the microcomputer that can be used for this is simple. The reaction point and the reaction area can be designed freely by entering appropriate parameters with the help of keyboards.

The optimization of the setpoint specification with a one-time test run, which can be freely selected in length, is a prerequisite for the procedure according to the open control loop.

With the compilation of pairs of values and their evaluation according to claim 2, the basis is created for the fact that each measured value or average value for controlling the motor is available at any point and can be called up. This reaction point can also be corrected manually or by an appropriate program while the machine is running.

The modification of the method according to claim 3 ensures that the measured values evaluated on the sliver to determine the average values also have a mutual relationship. The average values obtained in this way represent the actual strip thickness with sufficient accuracy.

The determined and stored average values then become effective as manipulated values in the area of the sliver in which the initial values for determining the average value were measured.

The advantages of this control method are, above all, that the motor for driving the rollers, which are driven in a controlled manner, is loaded with already optimized mean manipulated values and that different manipulated variables can be applied at larger time intervals than the frequency of the measuring steps for Ensure capture of an accurate image of the sliver structure.

The position of the reaction point and thus the distance to be covered from the measuring point to the reaction point is automatically determined by the processor for various slivers according to the average fiber length entered at the terminal. To determine the absolute average sliver mass at the entrance, a length of freely selectable test sliver is run at the beginning of the processing of a new sliver type, from which the average sliver mass obtained at the outlet is determined externally and entered into the processor via the terminal, which then automatically sets the basic delay corrected that the required storage tape mass is observed.

To clarify the concern of the present invention, the special features are to be described in more detail using an exemplary embodiment with associated drawings.

Fig. 1

Verfahrensschema - Bandmassesteuerung

Fig. 2

Schema der Werterfassung, Lagezuordnung und Auswertung

Show it

Fig. 1

Process scheme - tape measure control

Fig. 2

Scheme of value recording, location assignment and evaluation

As shown in FIG. 1, a drive motor M1, which drives a pair of rotating measuring rolls 1, a measuring device 4 and the feed area 2, is located on one line, as shown in FIG. 1. Another motor M 2 drives the drafting rollers 3 after the draft zone. An encoder 4, preferably an absolute encoder, is arranged on the pair of measuring rollers 1 for recording the measured value of the actual value of the input band wet IW / EM.

As shown in FIG. 2, the measured actual value IW / EM is entered into the memory S and coupled with the value of the absolute position SW / R of the reaction point R, which results from the distance lR to be covered.
The actual value acquisition IW / EM can take place at any intervals x.
The processor P constantly checks the reaction points SW / R assigned to the actual values IW / EM by comparing them with the actual value IW / R to determine whether a pair of values IW / EM // SW / R has reached the reaction point R. If this is the case (IW / R = SW / R), according to the measured deviation of the strip thickness from the average strip thickness, the setpoint value SW / D is output to the motor M 1 via the frequency controller fN and the value SW / AT to the output terminal AT .
This changes the speed of the input motor M1 in such a way that the instantaneous unevenness of the strip is compensated for in the draft zone.
Due to the absolute time independence of the strip mass control, its effect is only determined by the distance covered by the axis of the input motor M1, the time tR between measuring the actual value IW / EM at the measuring point M0 and the output of the setpoint SW / D can always be different.
The writing of actual value measurement pairs IW / EM with the associated position of the reaction point SW / R and the output of setpoints SW / D are two different processes which are not necessarily linked to one another, but only use the same memory S. Writing new value pairs IW / EM / SW / R into the memory does not automatically result in the output of a setpoint SW / D.

• die Eingangsbandmasse EM
• die Dublierung D
• die Ausgabebandmasse AM
• die Istwertbandmasse des Probebandes IM/P

in den Speicher eingegeben.
Die Istwertbandmasse wird durch den Lauf eines in seiner Länge frei wählbaren Probebandes ermittelt und ist Voraussetzung, daß bei jedem beliebigen Faserband der Prozeß der Steuerung auf einem Grundverzug geeicht wird.To carry out the procedure, ET

• the input band mass EM
• the duplication D
• the output tape mass AM
• the actual tape mass of the sample tape IM / P

entered into memory.
The actual value sliver mass is determined by running a freely selectable length of the test sliver and is a prerequisite that the process of the control is calibrated to a basic delay for any sliver.

• Es ist kein Regelkreis mit einer der Verzugszone nachgeordneten Meßeinrichtung erforderlich.
• Es werden alle Ungleichmäßigkeiten im Band präzise bearbeitet, es bleiben keine Teilstücke zwischen Meßort und Kontrollort unbeeinflußt.
• Es ist keine Grenze für die Bemessung des Steuerbereiches im Plus- und Minusbereich gegeben.
• Die Lage des Reaktionspunktes ist nicht zwangsweise vorgegeben, diese kann den Verarbeitungsbedingungen angepaßt werden.
• Die Maschinengeschwindigkeit hat keinen Einfluß auf das Arbeitsregime, so daß Anfahr- und Abtourvorgänge der Maschine gleichermaßen exakt behandelt werden.
• Es ist keine externe Verzugsberechnung erforderlich, dies erfolgt intern im Prozessor. Am Terminal werden nur textiltechnisch relevante praktische Daten des Spinnplanes eingegeben.

Particular advantages of this procedure are:

• There is no need for a control loop with a measuring device downstream of the warpage zone.
• All irregularities in the strip are processed precisely, no sections between the measuring point and the control point remain unaffected.
• There is no limit for the measurement of the control range in the plus and minus range.
• The position of the reaction point is not mandatory, it can be adapted to the processing conditions.
• The machine speed has no influence on the working regime, so that starting and turning off of the machine are treated equally precisely.
• No external delay calculation is required, this is done internally in the processor. Only practical data of the spinning plan relevant to the textile technology are entered at the terminal.

Claims (3)

1. Process for equalizing textile slivers (fiber bands) in a drawing field with sliver feed rollers and sliver delivery rollers, whereby

   - the mass of the undrawn sliver is measured,

   - the values that are measured at intervals are successively stored,

   - a delay time is specified between the measuring process and the initiation of the correction process,

   - the stored measured values used for initiating the correction process are routed as rotational speed setpoint values to the motor (M1) of the feed rollers (2),

   characterized by the fact

   that absolute measured values (IW/EM) for the mass of the sliver are recorded in freely selectable steps (x),

   that these measured values (IW/EM) are stored in a memory (S) that is managed by a processor (P),

   that the stored measured values (IW/EM) are processed in groups and converted to an average value by means of a processor (P),

   that the average values (IW/EM) are stored in a form retrievable by the processor (P) together with the data (SW/R) of a reaction point defined as related to its position and

   that the average values (IW/EM) at the reaction point (R) are retrieved by the processor (P) independent of time according to a specified path traveled by the motor and are routed in the form of rotational speed setpoint values (SW/D) to the motor (M1)
2. Process in accordance with Claim 1, characterized by the fact that the average values (IW/EM) are each combined with the data (SW/R) of the reaction point (R) to form a value pair (IW/EM/ /SW/R) and
   that the value pair (IW/EM/ /SW/R) is retrieved from the data (SW/R) of the reaction point (R) by means of the processor (P) and routed as a rotational speed control output (SW/D) to the motor (M1).
3. Process in accordance with Claim 1 or 2, characterized by the fact

   that the average value derived from the successively stored measured values (IW/EM) of a measured range and

   that the value pair (IW/EM/ /SW/R) that comprises this average value is then retrieved when the beginning of this measured section reaches the reaction point (R).

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