DE1272784B - Method for regulating the draft of the fiber web in spinning preparation machines, in particular beating machines - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

DOIg

German KL: 76 b -3/01

Number: 1272784

File number: P 12 72 784.3-26 (C 24878)

Filing date: August 14, 1961

Opening day: July 11 , 1968

The invention relates to a method for regulating the draft of the fiber web on spinning preparation machines, in particular beating machines, with the number of the fiber web entering the machine and leaving the exit rollers is continuously measured and the value measured at the output to influence the input measured value is used and the value determined from it to regulate the delay serves, whereby the value continuously measured at the output concerns long-period number fluctuations, which are converted into a servomotor speed over certain lengths of the fiber web and the angle size 1 «after certain revolutions of the servomotor is the value of the integral corresponds to the number fluctuation with respect to time.

There are already devices on impact machines known which have a control and additional Control means include and serve to equalize the fiber material before spinning yarns. However, the control of such known devices acts on the conveyor rollers at the machine entrance, so that the additional control means used in an inverse relationship to the control of the feed side stand. Such known devices therefore have the significant shortcoming that when large Measured variable fluctuations the influence of the control has a cumulative effect, d. H. to an excess of the manipulated variable leads.

In a known method of the type mentioned at the outset, short-period fluctuations in the number of the fiber web are measured at the entrance to a beating machine, while the long-period fluctuations in numbers are measured at the machine exit. The measured values are then fed to a control mechanism which influences the speed of the feed roller via a controllable drive. In this known device, which comprises a control circuit for taking into account the short-period number fluctuations and a control circuit for taking into account the long-period number fluctuations, the spreading rollers (calender rollers) are driven at a constant speed. This necessarily results in the disadvantage that such a controlled or regulated machine cannot work satisfactorily when the inlet thickness of the fiber web on the machine inlet side assumes a value below a certain limit. These disadvantages can also occur under certain circumstances on carding machines, cards and winding machines in which the dispensing method is used to regulate the draft of the
Fiber web in spinning preparation machines, in particular beating machines

Applicant:

The Cotton Silk and Man Made Fibers

Research Association,

Didsbury, Manchester (Great Britain)

Representative:

Dipl.-Ing. R. Busselmeier, patent attorney,

8900 Augsburg, Rehlingenstr. 8th

Named as inventor:

Arthur Linnert,

Harold Catling, Didsbury, Manchester;

Albert Edward de Barr,

Cheadle (UK)

Claimed priority:

Great Britain 13 August 1960 (28 101)

rollers or the like are driven at constant speed as before.

This object is achieved by the fiber material of the machine in a known manner with one of their Regulating device supplied with uninfluenced and constant speed and a function generator is used, in which the value of the inlet thickness measured at the inlet · of the fiber web in a signal that corresponds to the value is converted and that continuously at the output of the machine an actual value of the fiber web thickness is measured and a difference is formed therefrom with its nominal value, which is converted into a corresponding speed of the servomotor, the angular size After certain revolutions of the servomotor shaft, η is proportional to the value

(D ₂ - D) German

is, and that the revolutions are then entered into the function generator and thereby the multiplication

109 569/167

the said constants α and b is made possible, so that is constant

a = P + q ((D ₂ -D) di b = m + η ((D ₂ -D) Ut,

the values p, q, m and η being selected and adjusted so that the error value of the difference (D ₂ - D) is reduced and that the value thus obtained is fed to a motor speed controller of the drive motor of the output rollers as a control variable and that the constant peripheral speed the feed roller or rollers is introduced into the motor speed controller as a further control variable and the two control variables thus introduced into the motor speed controller are converted in the latter into such a new electrical control variable that gives the drive motor of the output rollers such a respective speed that the exit speed of the fiber web is the same the value

D.

Compared to known methods and devices, the method according to the invention has to be carried out the same has the essential advantage that the controlled by the method according to the invention Beating machine satisfactory regardless of the inlet thickness of the fiber web on the input side of the machine is working. This considerable progress is made compared to what is known, in particular achieved that in the present invention the speed of rotation of the spreading rollers in accordance variable with the speed and the infeed thickness of the fiber web on the input side of the machine is. The control according to the invention thus enables the initial value with regard to the thickness (number) of the fiber web (cotton wool web) to a very specific value and to maintain this value constant.

In addition to control means, regulating means are also used to carry out the method according to the invention intended. As a result, the invention has, inter alia, the advantage that via the control loop all the property to be regulated during the passage of the fiber material through the machine influencing disturbance variables are taken into account, but without the regulation - in contrast to known designs - can exert a cumulative influence on the manipulated variable, since the control signal is only used according to the invention, together with the control signal in a Function generator to be fed where the actual control signal by multiplying with constant sizes is formed. This actual control signal is used to control the output characteristic the machine used in such a way that deviations from the desired property of the Fiber goods are compensated.

When controlling the output characteristics of the machine according to the invention, the desired characteristics are found Thickness (number) of the fiber web (cotton wool web) at the exit of the machine in the formation of the actual, the control signal acting on the output characteristics of the machine by processing the Control signal (manipulated variable) and the control signal (measured variable) in the function generator, so that long-period, in addition to short-period fluctuations of the to be regulated Property value in a technically advanced way to modify the operation of the machine can be used.

The figures of the drawing show an embodiment of the subject matter of the invention, namely shows

F i g. 1 is a schematic representation of an impact machine with the control devices according to the invention,

F i g. 2 is a partial view of the control device on the output side of the impact machine,

F i g. 3 is a partial view of the control device on the input side of the impact machine, 4 shows the circuit diagram of the function generator,

F i g. 5 the circuit diagram of the motor integration system,

Fi g. 6 the circuit diagram of an engine speed controller, the associated engine and system comprising a speedometer or tachometer.

The feed roller .R _{1 of} an impact machine S (Fig. 1) is driven by a motor CSM at a nominally constant speed. In order to be able to determine the occurrence of undesired variations in the speeds of the motor CSM , the speeds or the running speed are measured by means of a tachometer TA ₁ , which gives an electrical signal which corresponds to the speed V _{1 of} the feed rollers K _1.

The calender rollers KW and also the screen drums or centrifugal baskets as well as the devices for producing the finished winding of the beater are driven by a controllable motor VSM to which a tachometer TA _{2 is} coupled. The tachometer TA ₂ sends electrical signals which correspond to the speed V _{2 of} the calender rolls.

The control of the uniformity and uniformity of the material delivered by the impact machine S via the control circuit is accomplished by an input thickness energy converter TR ₁ , which by means of a hollow lever system (Fig. 3) emits a signal which corresponds to _{the intake thickness D 1.} To evaluate a known deviation from the linearity between the thickness of the fed fiber web and its surface density and also deviations in the reciprocal value or compressibility of the fed fiber material, a function generator FG is used, which converts a signal corresponding to the value of D ₁ into a value D ₁ = / (D ₁ ) = a D ₁ + b transforms the corresponding signal. The signal D ₁ is input into an engine speed controller or in an engine speed control element MSC ₁ , the task of which is

to hold, where D is the desired thickness of the applied fiber web (cotton wool web). This is achieved by an additional feedback, namely by the tachometer TA ₂ , as in FIG. 1 shown by a dashed line is achieved. A time delay in the effect of this control is not necessary in operation with regard to the working characteristics of the impact machine; however, it could be used on other types of machines with longer

working hours become necessary. However, if the energy converter TR _{1 is connected} upstream of the feed rollers of the beater, a time delay is necessary for this reason.

The control over the control circuit takes place via an energy converter TR ₂ , which shows deviations in the thickness of the applied fiber web (cotton wool web) and sends out a signal which corresponds to the value (D ₂ - D), with D _{2 being} the real strength of the delivered Fiber web is designated. This signal is in turn input into a further motor speed controller MSC ₂ , which controls an associated servomotor SM in such a way that it runs at a speed which corresponds to the value (D ₂ ~ D) . To ensure operational accuracy, a feedback, which is connected to the tachometer TA ₃ , is provided between the servo motor SM and the motor speed controller MSC ₂ (see the dashed line in FIG. 1). The final element in the control loop is formed by a mechanical element in the form of the shaft sh , which connects the servo motor SM and the function generator FG. Since the speed of the servo motor SM always corresponds to the value (D ₂ -D), its angular position and thus also the angular position of the shaft sh is dependent on the integral of this speed with respect to time, ie proportional to

(D ₂ - D) German

A rotation la is thus entered into the function generator FG which corresponds to the value

(D ₂ - D) German

35

is proportional , allowing the constants α and b to be modified so that is constant

a = ρ + q f (D ₂ - D) dt b = m + η j * (D ₂ - D) dt,

40

where the values of ρ, q, m and η are chosen and adjusted in such a way that they always strive to _{reduce the value of the error (D 2} - D).

The mentioned rotation 1 α can be derived as follows:

since λ η

- ~ ² - ^T W

45

50

German

la =

60

ndt + K;

it means

η = speed

Γ turns

mm

u = angle of rotation [degrees],
t = time [see],
K = constant of integration.

55

60

In the system described , the control exercised by the motor speed controller 'MSC ₁ is based partly on the action of a control circuit which is suitable for determining short-period variations which occur with regard to the properties of the material subject to the control, and partly on the influence of a control circuit which is intended to determine long-period variations in the properties subject to _{control A.} The control pulses regulate the operation of the impact machine in such a way that both types of variations are compensated for. Since the control is effected in such a way that the speed of the output rollers is varied, it is not necessary to generate reciprocal values for the purpose of the control, nor will a gradual emptying or exhaustion of the material supply have such a disruptive effect, as already described above but the application speed will be reduced to the extent necessary to compensate for the decreasing inflow of the fiber web.

As in Fig. 2, the calender rolls KW are provided in the usual manner on the output side of the beater S, and a plurality of detectors or sensing elements 12, which respond to vertical movements of the roll 11, are arranged above the upper roll 11. The two-sided calender frames 13 carry a plate 14 running over the entire width of the calender, which at each end carries a bearing block 15 which is arranged directly next to the corresponding bearing 11a of the upper calender roll 11. An arm 16 of the sensing element 12 is pivotably mounted on each of the bearing blocks 15. The arm 16 carries an energy converter 17 (TR ₂ ), the sensor of which rests on a bolt 18 which is carried by the bearing Ha . At the other end of each arm 16 there is a setting and comparison knife element which is known per se and is not described in greater detail here.

Each of the energy converters TR ₂ consists of a linearly variable differential transformer, which comprises a correspondingly excited primary and secondary coil, with a common core. This common core represents the sensitive part of the energy converter, which responds to the vertical movement of the calender rolls, which is caused by the changing thickness of the fiber web (cotton wool) running between the calender rolls. The electrical impulse or the electrical output power is proportional to the movement of the core and thus also corresponds to the thickness of the strip of material coming from the impact machine. The signal D ₂ -D comes about in such a way that the signal which originates from the energy converter is compared with a constant a which corresponds to the desired strength D.

On the input side of the percussion machine S , a well-known hollow lever system 19 is arranged in the usual way, which is based on a button lever system, but has been modified according to the invention in such a way that a rod-shaped end member 20 influences the energy converter TA ₁ . The energy converter TR _{1 also} represents a linearly variable differential transformer from which the signal D _{1 is} output (FIG. 3).

The electrical parts of the control system described are shown in the circuit diagrams in FIG. 4, 5 and 6 shown schematically. The F i g. 4th

shows a circuit diagram of the function generator FG and the associated components and switching elements.

The signal emanating from the energy converter TR ₁ is converted into a direct current signal by means of a rectifier and filter E and is amplified by an amplifier A ₁ . A bias voltage V _{A is} added to this signal, which goes through a resistor ^ ₁ and the size of which can be regulated by a variable resistor RV ₁ . Furthermore, a bias voltage V _{B is} added, which is proportional to the value

synchronizing PC so that

^άβ -Kin m

where (·) means the angular displacement or angular rotation of the shaft of the servo motor SM . The servomotor SM drives the control potentiometer RV _ir RV _h , (Fig. 4) via a gear GB (not shown) with a slip clutch, so that the movement of the potentiometer arm over time

(D ₂ - D) German

t = K \ (D ₂ - D) df

is. The bias voltage V _B goes through a control potentiometer RV _a and a fixed resistor R ₂ . The movable arm of the control potentiometer RV ₁₁ is operated by the servomotor SM , the voltage of which can be regulated by the variable resistor RV ₂ .

The regulation of the size of the bias voltage V _A by means of the variable resistor RV ₁ corresponds to the regulation of the parameter m, and the regulation of the size of the bias voltage V _B by means of the resistor RV ₂ corresponds to the regulation of the proportionality constant n.

The total signal is input to a second DC amplifier A ₂ , where the gain as a function of the value

(D ₂ - D) df

takes place in that the other part "of the servo potentiometer RV _{1 is connected} to a feedback loop which includes a variable resistor RV _3.

The overall gain experienced by signal D ₁ is given by the formula

^ - ^ RV _h j (D ₂ -D) dt + R shown which is equivalent to the expression

ρ + c]

-D) German

while the functional influencing variables can be determined by regulating RV ₃ and RV _h.

A circuit diagram of the motor integration system, which comprises the motor speed controller MSC ₂ , the servo motor SM and the tachometer TzI ₃ , is shown in FIG. 5.

The circuit of the motor speed controller, in which the signal D ₂ -D is input, comprises a preamplifier A ₃ , to which an output amplifier A ₄ . is connected downstream, which in turn feeds a coil of the bidirectional speed-controllable two-phase AC servo motor SM , while the other coil is fed via a phase compensation circuit from a transformer, not shown. The speed of the servo motor SM is approximately proportional to the input signal from A ₂ , but this element of the circuit is linearized by feeding back a signal from a resistance tachometer TA ₃ through a phase-out.

The F i g. 6 shows a circuit diagram of the system which comprises the motor speed controller MSC ₁ , the speed-controllable motor VSM and the tachometer TA _1.

The VSM motor is a 2 HP DC motor, the speed of which is controlled by a well-known full-wave thyratron armature.

The input signal D {= J (D ₁ ) coming from the function generator FG is amplified by the amplifier A ₅ and entered into the lattice circle GC of the thyratron. A precision DC tachometer generator PT takes over the feedback in order to ensure a linear frequency and to reduce the natural frequency drift in this part of the device to a minimum. Further feedback from E and F is used to secure maximum values for the frequency. These are combined in the circuit NC with the signal coming from the tachometer TA _{1 in} order to compensate for impermissible increases in the speed of the feed rollers R _1.

Claims (1)

Claim: Method for regulating the warpage of the fiber web in spinning preparation machines, in particular beater machines, the number of the fiber web being measured continuously when entering the machine and when leaving the output rollers of the machine and the value measured at the output is used to influence the input measured value and the result The value determined serves to regulate the delay, whereby the value continuously measured at the output relates to long-period number fluctuations, which are converted into a speed of a servo motor over certain lengths of the fiber web and the angular size 1 «after certain revolutions of the servo motor according to the value of the integral of the number fluctuations corresponds to the time, characterized in that the fiber web is fed to the machine in a known manner at a constant speed that is unaffected by its regulating device and a function generator (FG) is used in which the one at the inlet uf measured value (D ₁ ) of the inlet thickness of the fiber web is converted into a signal (D {), which corresponds to the value (a D ₁ + b) and that an actual value (D ₂ ) of the fiber web thickness is continuously measured and at the output of the machine from this, with its nominal value (D), a difference (D ₁ -D) is formed, which is converted into a corresponding speed of the servomotor (SM) , the angular size Δ α after certain revolutions of the shaft (sh) of the servomotor proportional to the value (D ₂ - D) German is, and that the revolutions are then input to the function generator, thereby enabling the said constants α and b to be multiplied, so that is constant P + q J (D ₂ - D) dt b = m + η Γ (D ₂ - D) dt, wherein the values p, q, m and η are selected and adjusted so that the error value of the difference (D ₂ -D) is reduced and that the so The value obtained is fed to a motor speed controller (MSC ₁ ) of the drive motor (FSM) of the output rollers as a control variable and that the constant peripheral speed of the feed _{roller (R 1} ) or rollers is introduced into the motor speed controller as a further control variable (F ₁ ) and the two are thus introduced into the Motor speed controller introduced control variables (F ₁ ) and (D ₁ ') in the latter are converted into such a new electrical control variable (SG) , which gives the drive motor (VSM) of the output rollers such a respective speed that the exit speed of the fiber web (F ₂ ) equal to the value Φ1 Considered publications:
German Patent Nos. 720 200, 1043 886;
French Patent Nos. 1210083,1237428; U.S. Patent No. 2,770,843,2,930,084. 1 sheet of drawings 809 »9/167 7.6t O Bundesdruckerei Berlin