EP0541794B1 - Process and device for correcting the moment and intensity of regulation - Google Patents

Description

The invention relates to a method and an apparatus for correcting the point of regular use and the intensity of regulation a regulation, a drafting system for slivers with the Features of the preambles from claims 1 and 12.

The task of regulation is to detect a change in the thickness of the sliver and to compensate for it by changing the warp.
The thickness signals are recorded at the measuring point in front of the drafting system entrance. On the subsequent path of the measured sliver points to the delay point, the associated measurement signal is buffered with a time delay. When this delay time has elapsed, the regulation is used immediately in accordance with the deviation from the sliver thickness. This point of use is the regulating point of use.

The problem here is that the regulatory point of application is not too early or too late compared to the default point, because that would be a default. The regulation intensity, i.e. the Gain should not be too small or too strong.

In practice, there are machine-internal influences or environmental influences the cause, so that the delay point is not precisely defined can become errors in the determination of the regulatory point of use and the intensity of regulation comes.

In the event of sudden fluctuations in the thickness of the sliver, for example, one that exceeds the tolerance limit The mechanical components for the drive can be needle impulses the drafting rollers are not fast enough due to their inertia consequences. A complete compensation of the fluctuation in thickness is in hardly possible in this case. The problem is exacerbated that there is a need, the speed of the sliver from an average of 500 m per minute to 800 m per minute and to increase more.

Another borderline case is fluctuations in thickness that grow very slowly over time. The reaction of regulation is not there either sufficient.

DE-OS 36 19 248 proposes a correction value for the delay time depending on the slope or the relative Determine the size of the mass fluctuation. The result is one Shortening the delay time depending on the slope and the size of the mass fluctuation. This solution has the disadvantage that the result of the regulation cannot be checked. This is disadvantageous in that it is due to internal machine influences or environmental influences affect the correction made can be.

The solution according to EP 412 448 suggests the use of a on the drafting system meshed control before, the measurement signal after the Drafting system output is recorded and evaluated. Purpose of the solution is the result of the controlled change in delay through monitoring at the drafting system outlet, in the same control system attributed and separated by low frequency and to evaluate the high-frequency component in an optimization process. The manipulated variable Y optimized by the main control thus becomes as setpoint for controller 8.2 of the drive for the main warpage 12 used (EP 412 488, page 12, 12th-15th line). This solution continues to assume that the measured values are always for one Use setpoint optimization. The crucial shortcoming with this procedure is that for the adjustment of the Correction values to be used are not independent and therefore not processed by the regulatory system without interference.

To make changes in regulation independent of regulation So far, the "tape test" carried out. The "tape test" is random and manual carried out to determine the correct regulation of Variations in the sliver thickness. A test tape is created. The operator places a single belt section on the feed belts or creates a limited interruption due to tape breakage. The length of the sliver produced is cut out and their actual strip thickness determined by weighing (see operating instructions RIETER Spinning Systems, section RSB 851, SB 851, point 4.5.6., Edition 8/1990). It is therefore a production stop unavoidable in the minute range. That is a essential disadvantage for continuous production at high Production speed.

EP 176 661 B1, column 4, lines 42 to 51 describes, as a solution, that in principle another closed loop was introduced is that of a measuring device at the exit of a drafting system takes the signals, converts them into electronics and the Parameters in control electronics of the open control loop are influenced. This further, closed control loop does not work directly on the regulation section, but on the regulation parameters of the open control loop. The regulation parameters are optimized through an iterative process. The iterative process works continuously throughout the operating life of the Regulating section. A disadvantage of this method is that The iterative procedure is used to achieve a desired regulating state is constantly being continued and thus the regulation is permanent Changes are suspended. There is no evaluation of the signal delivered by the measuring device at the output of the drafting system for regulation.

The object of the invention is a method and an apparatus to create the correction of the regulatory point of application and the Regulation intensity on regulation of the drafting system improved.

This object is achieved with a method or a device according to claim 1 or claim 12.

In contrast to existing regulatory procedures, the FFT analysis use to arrive at correction values, uses the invention Process the feature, only individual events of the sliver thickness to choose, and to do so independently of the existing one Regulatory system to start working within a given time range necessary corrections against the regulatory system (i.e. correction of the rule's starting point or the intensity of regulation). The method according to the invention is therefore not constantly in operation. The process only takes place when a special signal is detected put into operation and stopped after a specified period of time.

The procedure is not a return of the Control variable in the sense of a closed control loop or a Feedforward control.

The method requires a transient signal of the sliver thickness is present at measuring point 1. The transient signal must have a high amplitude so that it is clearly exceeded the tolerance limit of the sliver thickness with sufficient Period. At the same time, this amplitude must be steep possess that is significantly different from a permanent one increasing sliver thickness, but smaller than that of a needle pulse is.

This signal must be similar to a jump signal. This Jump signal is fed to regulation and used at the same time, the method according to the invention for correcting the regulating point of use and start regulating intensity. Regardless of Existing regulation uses the response signal as a pulse diagram recorded at the drafting system exit and its change in comparison evaluated to the jump signal to the regulating point and the Correct regulation intensity. The procedure is based on a defined period of time ended.

The device will be in parallel with the existing regulation Assemblies installed that both detect a transient Signal enable as well as an evaluation of the response signal with regard to the point of regulation and the intensity of regulation enable.

The advantage of the method is that it is independent and thus works without influence from existing regulation. This means that the correction value is determined more precisely because it is internal to the machine Influences or environmental influences on the delay point better can be taken into account. Related to that, Another advantage is partial automation of the "tape test" by adding a test tape in an automated manner is generated without interrupting the production process.

Because the process is the targeted selection of a random individual event deviating sliver thickness is required, none is required permanent operation of the process.

Figur 1:

Blockschaltbild zum Verfahren und zur Vorrichtung

Figur 2a:

Sprungsignal

Figur 2b:

Antwortsignal, Reguliereinsatz zu früh

Figur 2c:

Antwortsignal, Reguliereinsatz zu spät

Figur 2d:

Antwortsignal, Reguliereinsatz zu früh und Verstärkung zu hoch

Figur 2e:

Antwortsignal, Reguliereinsatz zu früh und Verstärkung zu niedrig

Figur 3 :

Blockschaltbild zum Verfahren und zur Vorrichtung ohne Reservebandzuführung.

The method of operation of the method and its interaction with a known regulating system is described below with reference to the figures in an exemplary embodiment:

Figure 1:

Block diagram for the method and the device

Figure 2a:

Jump signal

Figure 2b:

Response signal, regulating use too early

Figure 2c:

Response signal, regulating use too late

Figure 2d:

Response signal, regulating use too early and amplification too high

Figure 2e:

Response signal, regulating use too early and amplification too low

Figure 3:

Block diagram for the method and for the device without reserve tape feed.

FIG. 1 shows the block diagram for the invention Method with the essential features of the device. The sliver 5 passes through a measuring point 1. This measuring point 1 can be, for example, a pair of mechanical sensing rollers. Before the Measuring point 1 are the feed roller of the reserve belt feed 3 the reserve tape 4 shown. The drafting takes place in drafting system 6 of the sliver. At the exit of the drafting system is a measuring point 2 arranged. The conventional regulation system 7 receives from the Measuring point 1 the measuring signals. These measurement signals are stored in a measured value memory 7.1 saved with a delay and delivered to an amplifier 7.2, the output of amplifier 7.2 Signal is passed to an actuator 7.3. The actuator 7.3 changes the speed of a pair of rollers in the drafting system 6, see above that the delay changes.

In terms of the device, this described regulation system 7 an assembly 8 installed. This assembly 8 of the invention The process works in parallel and independently of the conventional one Regulation system 7. In assembly 8 are shown Control unit 8.1, a measured value evaluation 8.2, a counting and evaluation unit 8.3 and an averager 8.4, an intermediate. memory 8.5 and a comparator 8.6.

A reserve belt feed has the task of production downtimes to avoid by sliver break or by end of tape in a jug. The function of the reserve tape feed 3 is for the invention Transfer purpose to another application. The reserve tape feed 3 is double Part of a device used to carry out the method.

To start the process, one of the ways is that the Control unit 8.1 a start signal to the reserve tape feed 3 gives. After a defined time of supplying the reserve tape the reserve tape feed 3 is stopped again. This duration corresponds to the required duration of the procedure.

Another way to start the process is through the Submission tapes given themselves. This possibility is shown in FIG. 3 shown.

The tapes can even at the measuring point 1 before Drafting device 6 by random deviation of the sliver thickness Generate transient signal. Prerequisite is that the transient Signal has a high amplitude. The amplitude must be approx. 10% deviate from the mean and a time period (at least three Clock pulses of the measuring clock) are present. This signal must be recognized become. For this purpose is between measuring point 1 and control unit 8.1 a measured value analysis 8.0 arranged (Figure 3). With the Measured value analysis 8.0 is by means of long-term averaging Measured values set a comparison value. An overshoot by At least 10% of the comparison value is considered to be a threshold detected by the measured value analysis 8.0. The amplitude must thereby last at least a period of three clock pulses. The slope is determined in parallel with the determination of the amplitude. If their steepness also increases suddenly then the required transient signal is found. With The process is started when such a signal is detected. After a predetermined number of clock pulses, the process completed. The number of clock pulses corresponds at least to that Pass from measuring point 1 to measuring point 2.

The process works in parallel and independently of the existing one Regulation. With the connection of the reserve tape 4 or by random deviation of the sliver thickness, a defined one Jump signal according to FIG. 2a (shown in idealized form) triggered. This jump signal is sent to measuring point 1 given and the time course of the output signal is with the measuring point 2 detected at the output of the drafting system 6. The output signal can take, for example, idealized forms, such as shown in Figure 2b, Figure 2c, Figure 2d or Figure 2e. The the measuring point 2 has a subsequent evaluation 8.2 in the exit two paths, one path for the control of the regulating point of use and another path for control intensity control.

In the processing branch for checking the regulating point of use are according to the pulse diagram of the response signal two amplitudes recorded (FIG. 2d), the first amplitude generally used in the course and phase for evaluation becomes. According to FIG. 2d, the delay t and is evaluated the difference - f (t) between the basic level of regulation and the basic level of the response signal. As a result of the evaluation in assembly 8, these characteristic values for the assessment of the Effectiveness of regulation. According to Figure 1 these characteristic values as signals in the measured value memory 7.1 or Amplifier 7.2 of the existing regulatory system 7 introduced and enable a correction of the parameters in the regulation system.

For further understanding of the procedure, the following is Explanation given with supply of the reserve tape. With the feeder of the reserve tape 4, the measuring point 1 registers one sudden increase in sliver thickness. That corresponds to that Jump signal. With the detection of the jump signal at the measuring point 1, the control unit 8.1 receives the information about the start of the procedure. At the same time, the measured value evaluation 8.2 starts Averaging 8.4. This first detects those signals that until the response signal arrives, i.e. the corrected volume, Run into the measured value evaluation 8.2 at measuring point 2. These mean values formed are stored in the buffer store 8.5.

When the first edge of the response signal arrives, the averager is formed 8.4 again mean values for the duration of the Pass the response signal. These averages, however are fed directly to comparator 8.6, which is now also receives its values from the buffer 8.5. Ascertained the comparator 8.6 is the difference in amount between the basic signal level with the start of the reserve band and the one with the response signal supplied basic signal level. A possible difference the comparison corresponds to a measure of the regularity. The Output of the comparator 8.6 goes to an amplifier 7.2 the intensity according to the difference in amount and their polarity the reinforcement realized.

Simultaneously with the arrival of the edge of the first pulse of the response signal at measuring point 2 is the counting and evaluation unit 8.3 started via the measured value evaluation 8.2. After running the The counting and evaluation unit becomes the first pulse of the response signal 8.3 stopped again. This result is stored in the measured value memory 7.1 delivered. The number of clock cycles of the first The pulse of the response signal provides the characteristic value for the size the misalignment of regulation. The phase alga (polarity) says something about the direction of the misalignment, i.e. at In a positive phase position, the regulation is too slow, in a negative phase Phasing too fast. The last pulse of the response signal remains unconsidered. That is always a subsequent one Pulse of opposite polarity to the first. The simplicity this step is that the length of this counted impulse is already a measure for the time of the regular use. This characteristic value is fed to the measured value memory 7.1, which at the same time corresponds to the standard operating point according to the characteristic value corrected.

It is characteristic of the counting and evaluation unit 8.3 that this is started and stopped by the measured value evaluation 8.2 and works according to a machine-dependent measuring cycle 7.4. The machine-dependent Measuring timing 7.4 is synchronized with the sliver speed, so that the evaluation of the pulse diagram done at the right times.

Claims (14)

1. Process for the correction of the regulation onset point and of regulating intensity of the regulation (7) of a drawing frame (6) for fibre slivers with a measuring point (1) before the sliver enters the draw frame (6) to measure fibre sliver thickness said measuring point being connected with a regulation system (7) that regulates the draft in the draft system (6) and comprises at least one measured-values memory (7.1), that determines the regulation onset point, an amplifier (7.2), that determines the regulation intensity, and an adjusting element (7.3), a further measuring point (2) at the output of the drawing frame (6), and a component group (8) for the regulation which is connected with both measuring points (1, 2), characterised in that an accidental deviation of fibre sliver thickness is detected in form of a transient signal at the measuring point (1) before the entry of the drawing frame, said transient signal having a high amplitude which exceeds a tolerance limit of the fibre sliver thickness with simultaneously suddenly increasing steepness and that said transient signal is transmitted simultaneously to the regulation system (7) and to the component group (8) and said component group (8) by detecting the transient signal starts the process so that the result of the regulation is detected as a response signal at measuring point (2) and the curve of the response signals is evaluated by the component group (8), the characteristic values of the signal, which are determined by the relation between transient signal and response signal, being imported into the regulation system (7) for correction before the process of one run is finished.
2. Process according claim 1, characterised in that the amplitude of the transient signal exceeds a threshold value which is beyond a tolerance limit of the mean value of fibre sliver thickness.
3. Process according claim 2, characterised in that the amplitude must last for a period of time.
4. Process according claim 3, characterised in that this period must be equal to at least three clocking impulses of a measuring phase.
5. Process according claim 1, characterised in that the transient signal is similar to a surge signal.
6. Process according claim 1, characterised in that an accidental deviation of the fibre sliver thickness is transmitted as a transient signal by a reserve sliver feeding system (3) which feeds a reserve sliver segment (4) to the fibre slivers (5) to be processed.
7. Process according claim 1, characterised in that the evaluation of the response signal takes place by means of the component group (8) in a processing path (8.3) for the regulation onset point as well as in a processing path (8.4, 8.5, 8.6) for the intensity of regulation and the characteristic value of the signal to correct the regulation onset point is transmitted to the measured-values memory (7.1) of the regulation system (7) and the characteristic value of the signal to correct the intensity of regulation is transmitted to the amplifier (7.2) of the regulation system (7).
8. Process according claim 7, characterised in that the first amplitude is detected in the processing path (8.3) for the regulation onset point in accordance with the impulse diagram of the response signal, and that the period from the beginning of impulse rise until tapering of the impulse to the background signal level and the appertaining positive or negative phase position is ascertained, so that the actual position of the regulation onset point in the drafting zone is determined.
9. Process according claim 7, characterised in that an evaluation of polarity and of the difference amount between basic signal level of control and basic signal level of the response signal is carried out in the processing path (8.4, 8.5, 8.6) for the intensity of regulation.
10. Process according claim 8, characterised in that the counting and evaluation unit (8.3) is started by the measured value evaluating unit (8.2) when the forward flank of the first impulse of the response signal is detected, and is stopped when this impulse drops to its basic signal level with the number of impulses counted by the counting and evaluating unit (8.3) being a measure for the asynchronism of the onset of regulation so that this value is the correction value for the regulation onset point.
11. Process according claim 9, characterised in that the measured value evaluating unit (8.2), starting with the detection of the transient signal via the measuring station (1) and until the arrival of the input impulse flank of the response signal at the measuring station (2) causes the mean value former (8.4) to form mean values of the detected signals and to convey them into the buffer memory (8.5), whereby, starting with the detection of the input flank of the response signal, the corresponding mean values are formed for the duration of this signal and whereby these as well as the mean values stored in the buffer memory are transmitted to a comparator (8.6), with an amount difference being formed between the basic signal level at the start of the transient signal and the basic signal level supplied with the response signal while their polarity is ascertained, a characteristic value for the correction of regulating intensity being thereby formed.
12. Device for the correction of the regulation onset point and of regulating intensity of the regulation (7) of a drawing frame (6) for fibre slivers in which a measuring station (1) for measuring of the fibre sliver thickness is located before the entry of the sliver into the drawing frame, said measuring station (1) being connected to a regulation system (7) which regulates the drawing in the drawing system, this regulation system (7) comprising at least one measured value memory (7.1) that determines the regulation onset point, one amplifier (7.2) that determines the intensity of regulation, and an adjusting element (7.3) and another measuring station (2) at the output of the drawing frame (6), as well as a component group (8) for the regulation which is connected with both measuring stations (1, 2), characterised in that the measuring station (1) transmits an accidental deviation of fibre sliver thickness as a transient signal parallel to the regulation to a component group (8), where, if a transient signal has arrived, a control circuit (8.1) by means of a measured value evaluation (8.2) starts the evaluation of a response signal, transmitted by the measuring station (2), said measured value evaluation (8.2) starting the evaluation of the response signal on a path for the control of regulating intensity which is formed by a mean value former (8.4), a buffer memory (8.5), and a comparator (8.6), said comparator (8.6) correcting the intensity of regulation by means of a connection with the amplifier (7.2) if a difference resuits from the comparison, and said measured value evaluation (8.2) starting the evaluation of the response signal on a path for the control of the regulation onset point which is formed by a counting and evaluating unit (8.3), as soon as the flank of the first impulse of the response signal arrives at the measuring station (2), and stopping the counting and evaluating unit (8.3) after the running through of the first impulse, the number of the ascertained clocking impulses forming a characteristic value of the signal, which corrects the regulation onset point at the measured value memory (7.1) via a connection to this memory, before the correction for one run is finished.
13. Device according claim 12, characterised in that a reserve sliver feeding system (3) is connected to a control circuit (8.1) and the measuring station (1) is connected to the control circuit (8.1) and to the measured value memory (7.1) of the regulation (7) and that an input of the measured value evaluation (8.2) is connected to the measuring station (2), whereby the output of the measured value evaluation (8.2) is connected on the one hand with a counting and evaluating unit (8.3), the output of said counting and evaluating unit (8.3) being connected to the measured value memory (7.1) of the regulation (7) and said counting and evaluating unit (8.3) being connected to a machine dependent impulse generator (7.4), and is connected on the other hand with a mean value former (8.4) which has two outputs, one being connected directly to a comparator (8.6) and a second one being connected to a comparator (8.6) via a buffer memory (8.5), the output of said comparator (8.6) being connected directly to the amplifier (7.2) of the regulation system (7).
14. Device according claim 12, characterised in that the measuring station (1) is connected to a measured value analysis system (8.0) and to the measured value memory (7.1) of the regulation (7) and that an input of the measured value evaluation (8.2) is the connection with the measuring station (2), whereby the output of the measured value evaluation (8.2) is connected on the one hand with a counting and evaluating unit (8.3), the output of said counting and evaluating unit (8.3) being connected to the measured value memory (7.1) of the regulation (7), and is connected on the other hand with a mean value former (8.4) which has two outputs, one being connected directly to a comparator (8.6) and a second one being connected to a comparator (8.6) via a buffer memory (8.5), the output of said comparator (8.6) being connected directly to the amplifier (7.2) of the regulation system (7).

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