EP1932957B1 - method of stopping a warp knitting machine - Google Patents

Description

The invention relates to a method for stopping a knitting machine, the components of which are operated in accordance with the signals of a moving leading axis coordinated with each other, wherein the process of stopping is initiated by the triggered once a stop event.

Knitting machines of the type mentioned are well known. They are used to make knitwear in all fields requiring the use of textile fabrics. It is also an important field of application of the knitting machines to join together sets of yarns deposited on one another, which serve as reinforcing inserts in the art of fiber composite construction, cf. eg the DE 197 26 831 C5 , The main driven components of the knitting machines are the knitting tools, the decisive for the laying cycle shotgun, weft or shotgun, the warp beam, ggs. a warp beam, with the supply of warp threads and / or the fabric take-off.

In older knitting machines, the components are all driven by a central main drive motor, with which they via intermediate gear, transmission links u. Like. Be in operative connection. Since the movement of the components has to be coordinated with each other, the drive here also serves to control the components. If there is no slippage between the shaft of the drive motor and the main shaft of the knitting machine driving the knitting tools, as can occur by means of V-belts, the shaft of the main drive motor is at the same time the leading axis which determines the course of all movements. In the presence of slippage, the main shaft of the knitting machine, ie the common drive shaft of the knitting tools, must serve as a guide shaft.

In newer knitting machines, the components are increasingly driven individually by computer-controlled servomotors, such as the DE 198 16 440 C1 shows. From the DE 102 43 398 A1 It is even known to drive the individual knitting tools of a warp knitting machine, ie needle bar, closing wire bar and lever, separated by its own servo motors. The servomotors are connected to a programmable electrical control. A memory connected to the controller contains the necessary information for executing the coordinated working movements of the knitting tools, which are recurring in every working stroke. The components are then controlled by a computer numerically controlled, a structurally designed leading axis is not available; for reasons of clarity, however, one can speak of a virtual master axis.

• eine Umdrehung der Hauptwelle der Wirkmaschine,
• eine definierte Anzahl von Umdrehungen der Hauptwelle entsprechend einem Musterrapport,
• eine Doppelmasche an einer Wirkmaschine mit Doppelnadelbarren,
• einen Schusslegezyklus (Schusseintragsmaschine),
• einen gemeinsamen Legezyklus mehrerer Schusslegestationen.

The signals of the master axis are repeated periodically; They form a master axis cycle in accordance with the repetitive motion processes of the knitting machine. A master axis cycle can be defined in various ways, for example by

• one revolution of the main shaft of the knitting machine,
• a defined number of revolutions of the main shaft according to a pattern repeat,
• a double stitch on a knitting machine with double needle bars,
• a firing cycle (weft insertion machine),
• a common laying cycle of several Schusslegestationen.

The knitting machines of all these designs have the disadvantage that an undefined stop position comes about when they are turned off. Initially, a stop event is triggered manually or automatically. The normal stop can be performed manually by depressing the stop button or / and if necessary selecting a desired stop position or the emergency stop by pressing the emergency stop button. The possibilities of an automatically triggered machine stop are manifold: For example, a thread break detector can respond to a thread break and that Trigger stop event for a normal stop. The same can be effected by a device for monitoring the thread tension, by a counter for the length of the running web (meter counter), by safety light barriers, by fault messages from the hardware used or simply by mains voltage failure.

In the knitting machines mentioned so far it is left to the system-related coincidence when the stop event makes their drive ineffective. In a sense, the knitting machine brakes itself down; in simplified terms, it is also possible to speak of a running out of the knitting machine, although the frequency inverters and servo motors customary today can develop a considerable braking effect even when switched off. At some point, the leading axis on the knitting machine also comes to a standstill. The stop position of the knitting machine, that is, its components, remains undefined. So it can not be foreseen or defined in which position of the leading axis cycle the knitting machine stops.

In this case, the knitting machine can remain in a position which affects the produced goods or the active elements unfavorable or even harmful. For example, the main shaft can fall back after switching off the position controller by their own momentum, which results in the dropping of mesh, the product is therefore faulty. Furthermore, a stop position may result in which the knitting tools are engaged, ie in the stitch formation, which means increased wear. Or it may result in a stop position in which the pattern repeat is not yet completed. In another, unintentional stop position can be exerted by thread tension, a train on the active elements, which also means increased wear.

But not only for the produced goods and knitting tools can an undefined stop position be harmful. This can also make it difficult to make an action when the standstill of the knitting machine intended action. For example, if the knitting tools or other machine elements in the stop position are not freely accessible, can they can not be serviced or replaced. Or the immediate repair of thread breaks can be difficult.

In practice, the disadvantages mentioned have often been compensated by the fact that after the accidental machine downtime with a subsequent crawl a better suitable stop position was approached. Other attempts have been to achieve a satisfactory stop position from the undefined stop position with alternating restarting. Apart from the associated loss of time but was found in this approach as a disadvantage that any interruption of the normal process of action such as stopping, starting and stopping the hand leads to errors in the knitted fabric, the so-called stand rows. These can be visible over the entire fabric width and mean a quatitäts deficit in the knitted fabric.

An improvement brought a knitting machine according to DE-A-2 419 694 in which the one-time triggering of the stop event until the standstill of the knitting machine leads in one go to a defined stop position of one or more of the components. In this knitting machine, a main motor with a rotation angle detector is present whose pulse trains are the basis for the control of knitting tools. The knitting tools are driven by individual stepper motors which receive their control commands from the machine control via a pulse distributor and special drive mechanisms. The stepper motors control the guide rails. When switching off the knitting machine, the speed of the main motor is reduced to a set low value; Finally, after information about the completion of a course of stitching, a signal for switching off the power source is given without the need for further operator access. The deceleration thus takes place in two steps and should cause the main shaft of the knitting machine to come to a standstill in a favorable position. Deceleration of the main drive shaft begins immediately with the delivery of the stop signal. Furthermore, the tools are turned off for themselves, the main motor is no longer the leading axis for the deceleration process. The braking distance, after the the knitting tools come to a stop in a predetermined position must be known in advance.

According to the DE-A-28 54 257 Different variants of weaving and knitting machines are to be shut down decentrally. For this purpose, the individual machine components are disconnected from the main drive and seek independently of each other a preferred end position. It is also possible to shut down one component in overdrive and the other in smooth operation. The components are braked by special braking devices; the braking distance must be known in advance. If one of the components does not stop exactly in the desired position, a fault is detected and the brakes must be readjusted. This method thus requires exact and expensive braking devices that must be constantly monitored and readjusted.

In the EP-A-0 684 331 A1 is a knitting machine described in which each individual knitting tool is linearly displaced by a separate stepper motor via a cranking operation in two mutually perpendicular planes. Each crank drive has its own microprocessor, with all microprocessors being coordinated via a central control. A separate zero position can be set for each stepper motor, and the zero positions of all stepper motors can be coordinated by the central controller. In the event of a power failure, each stepping motor moves in accordance with the programmed operating conditions, which must be known, in its predetermined zero position and thus also in a defined end position of the associated knitting tool. Even with this known control device must be determined in the design of the program, with which speed, acceleration or deceleration the necessary steps for approaching the zero position in case of power failure is approached. The known method of stopping the knitting machine, which is only geared to knitting tools, thus operates in a decentralized manner and is not set flexibly to different stop events.

Finally, out of the US-A-2,779,448 a knitting machine is known, which corresponds to the preamble of claim 1 of the present application. In this known knitting machine there is a main shaft which drives the control members for influencing the needle bars via two cams. The main shaft is driven by means of a V-belt via an electromagnetic actuated clutch. Further, an electromagnetically actuated brake is present; the operating mode is set so that either the brake or the clutch is active. The knitting machine shuts down by decelerating the main shaft and the driven needle bars closely follow this deceleration. It is expressly intended to stop in a predetermined position of the knitting tools. When the stop switch is pressed, a control program with three relays is de-energized, decoupling the main shaft from the drive and decelerating it by the brake. The shutdown and stop process is automatic, no further operator intervention is required. At the end, the main shaft should remain in a preselected position.

According to the US-A-2,779,448 the main shaft continues to run after the stop signal is triggered. For this purpose, an electrically conductive control disk is provided which controls the triggering of a control circuit with the three electrical relays, wherein a scan is carried out via contact brushes. When the scan passes through an isolation point on the control disk, the braking process becomes active and the main shaft comes to a standstill. The angular position of the insulation point on the main shaft is adjustable and corresponds to the braking distance of the knitting machine. Based on empirical values, a rotation angle corresponding to the braking distance is set permanently before the starting of the knitting machine. The isolation point on the control disc thus defines an intermediate position and triggers a phase of controlled active deceleration, which then eventually stops at a defined stop position. Even with this prior art knitting machine thus determined by testing braking distance must be set electromechanically fixed and repeatedly checked and readjusted in the course of operation.

In contrast, the invention has for its object to improve the method for stopping a knitting machine according to the preamble of claim 1 in such a way that the defined stop position of one or more of the components at different stop events and changing operating conditions in each case under conditions , which are adapted to the stop event, with a selbstätige reliable operation without complex control, maintenance and readjustment is guaranteed.

This object is solved by the entirety of the features of claim 1.

The method according to the invention does not only relate to defined stop positions of the knitting tools. The stop position of one or more specific components of the knitting machine is an exactly predefined position within the leading axis cycle. By this invention is brought about in the fastest technically possible and meaningful way, it is ensured that the knitting machine is at a standstill in a state that is optimally focused on the previous stop event and / or subsequently required action on the knitting machine. So it can be realized a stop position in which neither quality reductions of the product or increased wear or damage to machine parts are to be feared and / or in the need for subsequent maintenance or repair work can be easily made.

• eine Stopp-Position, in der ein Rückfallen der Hauptwelle durch Eigendynamik ausgeschlossen ist, in der sich also die Hauptwelle bzw. die Nadeln im unteren Totpunkt (u.T.) befinden;
• eine Stopp-Position für den freien Zugang zu verschiedenen Maschinenelementen, z.B. beim Platinenwechsel;
• eine Stopp-Position für den sofortigen Fadeneinzug;
• eine Stopp-Position für den Wechsel eines Teilkettbaumes;
• eine Stopp-Position am Anfang oder Ende des Musterrapports; die Musterelemente werden also vor dem Maschinenstillstand noch fertiggestellt;
• eine Stopp-Position nach Beendigung des Maschenbildungsvorganges;
• eine Stopp-Position nach Beendigung eines Schusslege-Zyklus;
• eine Stopp-Position nach dem Ansprechen des Meterzählers.

Such defined stop positions to be achieved with the method according to the invention may be the following:

• a stop position in which a fall back of the main shaft is excluded by momentum, in which so the main shaft or the needles are in the bottom dead center (uT);
• a stop position for free access to various machine elements, eg during board change;
• a stop position for immediate thread feeding;
• a stop position for changing a sectional warp beam;
• a stop position at the beginning or end of the pattern repeat; the pattern elements are thus completed before the machine is stopped;
• a stop position after completion of the stitch forming operation;
• a stop position after completion of a firing cycle;
• a stop position after the meter counter has responded.

The process for stopping the knitting machine is performed in one go. That is, if the stop event is triggered once, e.g. manually by depressing the stop button, the desired defined stop position of at least one of the components is automatically achieved without another operation process, solely by controlled deceleration of the leading axis movement. The method according to the invention thus also works faster than the procedure hitherto usual in practice, in which the knitting machine must again be approached step by step in creeping travel and thereby brought into the desired position.

The controlled deceleration of the leading axis motion does not mean that the delay must occur immediately upon the triggering of the stop event. Normally, during certain stop events, the leading axis movement will still remain in the state of motion that prevailed prior to the triggering of the stop event. Mostly this will be the steady movement of continuous operation; but it can also be the acceleration during startup of the knitting machine. The reason for this is that the machine control must first obtain the relevant influencing variables in order to influence the master axis movement. It is important to combine the respective stop event, the optimal stop position of one or more components, and the braking distance of the knitting machine and its components which is possible and meaningful in the present state of motion. Since these influencing variables are known for a specific knitting machine and can be stored or calculated, the machine control can automatically execute the deceleration process until the leading axis stops.

The servomotors of the components must follow the position of the master axis strictly synchronously. If several of the components are to reach a defined stop position at the same time, those positions of the master axis must be waited for, with certain components at the same time being in their selected stop position. The deceleration or braking distance is then correspondingly longer. In any case, however, deceleration is achieved solely by controlled action on the master axis motion, with the servomotors following the components accordingly. Special mechanical brake devices are not required.

In the method according to the invention, the technically possible and meaningful braking distance Δs is calculated for the movement state present when the stop event is triggered, with which the knitting machine can be shut down. In addition, the standstill position of the master axis is given, in which one or more of the components are in the desired defined stop position. By now mathematically the desired standstill position of the master axis is shifted back by the amount of the braking distance .DELTA.s, results in an intermediate position of the master axis in which the phase of the controlled, active slowing down the Leitachsbewegung is triggered. When the standstill of the master axis and components has been reached, the components are in the intended defined stop positions.

The required influencing variables for the controlled deceleration of the leading axis movement are determined by the already existing computer of the machine control in a particular case. In simple cases, retrieving averages from an electronic memory is sufficient.

In a knitting machine with a central main drive motor can be according to claim 2, the drive shaft of this central main drive motor itself is the relevant guide axis for performing the method.

Another possibility is that according to claim 3, the relevant leading axis through the main shaft of the knitting machine, so the common drive shaft of the knitting tools, is formed. This is particularly advantageous if there is a drive subject to slippage, as may be the case, for example, when driving by means of a belt. In this case, the main shaft of the knitting machine as the leading axis of a slip of the drive is independent. The Leitachsbewegung can then be derived from a located on the main shaft rotary encoder.

In today's high-performance knitting machines, the control and synchronization of the individual components is computer-controlled in each case. It is expedient that the master axis according to claim 4 is a virtual master axis formed by the software of the computer.

According to an advantageous embodiment of the method according to the invention is provided according to claim 5 that the servo motors of the components of position signals of the master axis are position-controlled. In such a method, which proceeds according to the master-slave principle, each position of the master axis is assigned in a strictly synchronous context, an associated position of the servomotors for each of the components. This refinement leads to a high degree of accuracy in the course of the method according to the invention, in which it is important to combine a certain defined stop position of a component, and thus also the stop position of its servomotor, with a braking path that is to be maintained as accurately as possible.

The advantages of this method are the more pronounced the more the drive of the components is decentralized, that is to say by computer-controlled servomotors. The implementation of such a method takes place in a time range of milliseconds.

In a further development of a computer-controlled method, it may also be expedient to form an additional signal according to claim 6 when stopping a knitting machine, whose drive is subject to slip, and to introduce it into the method, which takes into account the slip shortly before reaching the stop position.

Depending on the configuration of the knitting machine and its control can be provided in an advantageous manner according to claim 7, that in the course of a once triggered stop event, several components at the same time reach a defined specific stop position for them. For example, it is readily possible that together with the bottom dead center of the main shaft and a certain position of the wagon in the laying cycle and at the same time the end of the pattern repeat are achieved as defined stop positions. Since the position of the components is strictly synchronously bound to the position of the leading axis, they are also strictly coupled with each other. Therefore, an extension of the braking and discharge path is usually associated with this approach, the more components must be considered, the less common are the positions in which the defined stop position is common to all components.

With strong decentralization of the drives with individual computer-controlled driven components, but it is also possible with the embodiment of the method according to claim 8 that individual components reach their defined stop position at different times, while other components are still in motion. In this way, the braking and the Auslaufweg can be shortened without having to do without the fact that defined stop positions of different components in the final state are common.

Naturally, the defined stop positions are not to be observed as physically absolutely exact values. A certain tolerance for the end position must be taken in any case. However, the method according to the invention can be designed from the outset according to the embodiment according to claim 9 in an advantageous manner such that at the standstill of the knitting machine at the relevant components, a defined stop position window is reached. The execution of the computer control becomes more economical. If, for example, a main shaft revolution is divided into 3600 units in the computational design, then such a stop-position window can be in a range of +/- 5 units or +/- 0.5 °. It is then only desired that the leading axis and thus the component in question come to a halt without restarting within the window.

With the development according to claim 10, the possibility is created to take into account a sudden further stop event that occurs during an already ongoing stopping process. The short computation times make the subsequent change of an already running deceleration ramp possible.

• Fig. 1 zeigt in der üblichen Darstellung von Bewegungs- oder Bremsrampen Beispiele für ausgewählte Stopp-Positionen einer oder mehrerer Komponenten einer Wirkmaschine.
• Fig. 2a erläutert den zurückgelegten Weg s der virtuellen Leitachse in Abhängigkeit von der Zeit t beispielhaft für ein erstes Stopp-Ereignis.
• Fig. 2b ist die entsprechende Darstellung für ein weiteres Stopp-Ereignis.
• Fig. 2c zeigt die den Figuren 2a und 2b entsprechende Darstellung im Falle des Normal-Stopps.
• Fig. 3 ist ein beispielhaftes Ablaufdiagramm mit den Programmschritten zur Ausführung des erfindungsgemäßen Verfahrens.

The invention will be explained in more detail below with reference to selected exemplary details. In the figures, the following is shown:

• Fig. 1 shows in the usual representation of movement or braking ramps examples of selected stop positions of one or more components of a knitting machine.
• Fig. 2a explains the distance covered s of the virtual master axis as a function of the time t as an example for a first stop event.
• Fig. 2b is the corresponding representation for another stop event.
• Fig. 2c shows the the FIGS. 2a and 2 B corresponding representation in case of normal stop.
• Fig. 3 is an exemplary flowchart with the program steps for carrying out the method according to the invention.

The embodiment is based on a computer-controlled knitting machine, the components of which continue to take their synchronized in the required manner coordinated positions in accordance with the position of a virtual master axis strictly synchronously. There is a position or position control, in which the servomotors, which drive the individual components, follow the master-slave principle of the respective position of the virtual master and even have to assume a position corresponding to the respective position of the virtual master. The components may be prescribed relative motion, for example moving 10,000 units. However, the command can also be to execute an absolute movement, ie to approach a certain position ("drive from the current position or a defined position to position 10,000"). In the multitasking process, all servomotors receive their position or position commands from the same virtual master axis at certain constant time intervals (task cycle). The virtual master axis itself is time-dependent controlled. Thus, if a certain path segment of the virtual master requires a greater time interval until it has traveled, this means a slowing of the motion, which must also be followed by the servomotors of the components. The same applies for a shorter time interval, ie for an acceleration.

When describing the movement processes, distances in steps, that is to say step intervals, so-called units, are specified because the basic principle of the control is a position or position control. If one revolution of the main shaft corresponds to a stitch formation on the knitting head, then this process can be based on 3600 path units or step intervals, which corresponds to a resolution of 0.1 °.

In the five representations of FIG. 1 the abscissa represents the path progress s of the virtual master axis, which can be imagined in units of distances or revolutions. On the ordinate in the partial representation a of the leading axis cycle LZ is shown in the form of a movement ramp. In this case, it corresponds to 60 revolutions of the main machine shaft and thus also to a mesh count of 60 stitches per LZ master axis cycle. After the end of a leading axis cycle LZ corresponding to point S5 on the abscissa, the next leading axis cycle begins.

The partial diagram b shows - also in the form of movement ramps - the revolutions of the main machine shaft. The main shaft of the knitting machine is representative of the knitting process, because in most cases the knitting tools are driven by the main shaft via gear and lever. The partial diagram b clearly shows how the bottom dead center UT is traversed 60 times within a master axis cycle LZ.

In the partial diagram c, the movement of a firearm is shown as a movement ramp. The wagon is also referred to as a weft and puts the weft threads in the chains of the longitudinal conveyor. In this case, in the example of the partial diagram c, the laying cycle is set at 30 courses, ie two feeding cycles are carried out for each leading axis cycle LZ. According to example c, a passage of the firing carriage results from left to right or vice versa during 30 revolutions of the main shaft. Thereafter, each of the next cycle of the shotgun begins.

The partial diagram d illustrates the movement ramp of the pattern repeat, which is repeated here after 20 revolutions of the main shaft.

Partial diagram e shows another example of the movement ramp of a firearm. Deviating from the partial diagram c, the laying cycle of the firing carriage in example e is set to ten revolutions of the main shaft; during 10 revolutions, a crossing of the wagon takes place from left to right or right to left. For each lead-axle cycle LZ, six lay cycles of the wagon come about.

In FIG. 1 shows clearly that when driving a selected stop position very often and thus quickly the bottom dead center of the main shaft can be achieved. Selected breakpoints for the wagon, such. B. in the middle of its lay cycle are rarer. All the more, this applies to the pattern repeat. This already shows very clearly that a longer way to reach the desired stop position is required if certain stop positions are to be maintained at the same time when stopping the knitting machine for several components.

In the case of a Kettfadenbruches will endeavor to stop the knitting machine very quickly and, above all, to ensure that the main shaft stops in the area of its bottom dead center UT. This condition can be achieved after relatively few revolutions of the main shaft. The connection goes in FIG. 1 from the partial view b, wherein the stop event of Kettfadenbruches is indicated on the abscissa with SE1, the resulting coming stop position in bottom dead center UT of the main shaft with the point S1.

Another stop event is a weft break; this event is labeled SE2 and for convenience of illustration in FIG FIG. 1 exemplarily placed in the same place as the event of Kettfadenbruches SE1. In the case of a weft break, the stop position must be next to the bottom dead center UT of the main shaft and a certain position of the Schusswagen be achieved. In this case, the representation c shows a stopping of the firing carriage in the middle of the track, cf. the point S2, and the representation e a stop shortly before the end of the laying cycle, cf. the point S3.

If the meter counter is reached, this triggers the stop event SE4 and stops at point S4, thereby also combining a bottom dead center UT of the main shaft with a center position of the firing carriage.

An exemplary normal stop is detected at points SE5 and S5. The normal shutdown as a stop event takes place in point SE5. In this case, one has sufficient time to stop all relevant components at the same time in selected positions, namely the bottom dead center UT of the main shaft in conjunction with an end of the laying cycle and the end of the pattern repeat, cf. the point S5. In principle, it is also possible to proceed in the case of the stop event SE4 in the same way.

The point S6 illustrates the standstill of the knitting machine in the event that the mains voltage fails. Since the servomotors have stored a certain energy and feed them back in the event of mains voltage failure, the control of the knitting machine can still bring about a stop position in which the main shaft is at bottom dead center.

It is different in an emergency stop, for example, if a threat threatens or has occurred. In this case, no preferred position can be approached, resulting in the shortest possible braking distance, a random position corresponding to the point S7.

The defined stop positions are achieved solely via the controller and the computer of the knitting machine, without any additional mechanical intervention would be required by the arrangement of additional components such as a brake.

The FIG. 2a shows a typical movement sequence of the virtual master axis in a warp breakage as a function of time. Shown is the way s of the virtual master axis over time t. In continuous operation of the knitting machine is the steady state, therefore, the trajectory I of the virtual leading axis is a straight line. She would continue in her dashed representation on. But at time TE1, the stop event of the warp break occurs. The virtual master axis is located at the point SE1 at this time. Taking into account all relevant movement parameters, the computer of the machine control now calculates the minimum braking distance Δs in which the knitting machine is to be sensibly stopped. This also corresponds to a certain stop time t _s . The desired stop position in the case of Kettfadenbruches is the bottom dead center UT of the knitting machine main shaft. On the time axis results in the possible time T1 of the machine stop after a stop time t _s of 4 sec. By computationally backward-shifting the stop time by the stop time t _s results in the time TB1 at which the braking process is initiated got to. The virtual master axis is at this time TB1 in the intermediate position SB1. The path curve I of the virtual master axis is now in the delayed course I 'over, like that FIG. 2a can be seen above. The virtual master axis remains at the stop point T1 at the standstill point S1 after the braking distance Δs has been completed. Since the components of the knitting machine of the virtual master axis are followed strictly synchronously according to the master-slave principle, the main shaft of the knitting machine, as intended, also remains in its bottom dead center UT.

The special feature is that the braking process was not triggered immediately at the occurrence of the stop event SE1 at the time TE1, but that the lead time t _{v is} waited until it is ensured on reaching the intermediate position SB1 that the thus triggered phase of the controlled, active slowing down to a standstill position S1 and thus to the defined stop position UT of the main shaft leads.

For better clarity are in FIG. 2a below the path representation also the associated course of speed and delay of the virtual master axis shown.

FIG. 2b is one of the FIG. 2a corresponding representation for the case that the stop event SE2 is a weft breakage. In this case, not only does a defined stop position have the main shaft of the knitting machine in its bottom dead center UT. In addition, the shotgun must take a defined position, for example, in the middle of the track, as the basis of FIG. 1 has been explained. This results in a longer minimum braking distance Δs and a correspondingly longer stopping time t _s . The system of designations is in FIG. 2b same as in FIG. 2a (Stop event at point SE2 at time TE2, intermediate position at point SB2 at time TB2, standstill of the leading axis at point S2 at time T2). The representation is therefore readily understandable: The decisive factor is again the intermediate position SB2, at which the phase of the controlled active deceleration was initiated.

Figure 2c shows the corresponding representation for the case of normal stop. The designation of the symbols with the large letters is the same as in the case of the symbols FIGS. 2a and 2 B , but with the number 5 as Ordnungsziffer. In this case, there is sufficient time available, and defined stop positions of the machine main shaft, the firing carriage and the laying cycle can be maintained simultaneously and together. It would therefore be stopped at the end of a leading axis cycle LZ. The lead time in this case is longer in comparison to the previous cases, ie it can be stopped gently.

It may also be an overrunning of a longer stop event by a shorter one if, during the lead time, or even during the ramp, another stop event (eg, thread break) requires a faster off-timing than the overall optimum.

FIG. 3 is a flowchart showing by way of example how the virtual master axis is controlled by the software of the computer in the inventive method. The program steps are called cyclically by the multitasking operating system. In the query stage A1 is queried whether a stop event exists. If the answer is "no" this is done Signal 1 and no further reaction. If the answer is "yes", the signal 2 is passed on to the computing stage B1 via an emergency stop or via a normal stop.

In B1, the calculation of the stop parameters takes place depending on whether there is an emergency stop or a normal stop. These are above all the required and possible delay a _neg as well as the limit values of the motion parameters. Subsequently, in the requesting step A2, the required stop type is asked for different conditions. A distinction must be made between the undefined stop position and the defined stop position. An undefined stop position can be controlled in crawl travel, but may also be required in absolute emergency as a prerequisite for the fastest possible standstill. A defined stop position is sought in normal stop, but also in an automatically triggered machine stop, which does not necessarily require the fastest possible stop. This is z. B. Kettfaden- or weft break the case; Similar conditions are present at the stop from the overdrive.

1. 1. Berechnung des Mindestbremsweges Δs unter Berücksichtigung aller relevanter Bewegungsparameter, nämlich:
   • Stopp-Zeit t_s,
   • aktuelle Geschwindigkeit v,
   • eventuelle Beschleunigung a_pos,
   • Ruckzeit t_r, (eine Zeitkorrektur, die dem Umstand Rechnung trägt, dass der zeitliche Ablauf der Geschwindigkeit entgegen der schematisierten Darstellung in den Fig. 2a bis 2c nicht in Geraden mit scharfen Knickpunkten, sondern an den Übergangsstellen abgerundet verläuft).
   • Verzögerung a_neg,
   • Zykluszeit des Tasks t_zyklus.
2. 2. Bewertung des Bremsweges und eventuelle Korrektur mit Default-Werten als Standardwerten der Plausibilität oder Geschwindigkeit (z. B. bei sehr kleinen Wegen).
3. 3. Berechnung des zurückgelegten Weges während der Berechnung und Verknüpfung mit dem Mindestbremsweg Δs unter Berücksichtigung aller relevanter Bewegungsparameter, nämlich der aktuellen Geschwindigkeit v und der Anzahl der Taskzyklen während der Berechnung. Der Vorgang des Anhaltens spielt sich im Bereich von Millisekunden ab, so dass selbst die Zeit zur Berechnung des Stoppsignals in die Berechnung selbst eingehen muss.
4. 4. Berechnung der absoluten Stopp-Position unter Berücksichtigung des berechneten Bremsweges und der gewünschte Stopp-Position (je nach Stopp-Ereignis) im Leitachs-Zyklus.
5. 5. Vorgabe und Starten einer Absolut-Bewegung der virtuellen Leitachse auf die errechnete Stopp-Position der Leitachse mit den ermittelten Bewegungsparametern.

If a defined stop position is desired, the signal 3 is sent to the computing stage B2. In this, the defined stop position of the master axis is calculated. The calculation is made in the following essential stages:

1. 1. Calculation of the minimum braking distance Δs taking into account all relevant movement parameters, namely:
   • Stop time t _s ,
   • current speed v,
   • possible acceleration a _pos ,
   • Jerk time t _r , (a time correction that takes into account the fact that the time sequence of the speed contrary to the schematic representation in the Fig. 2a to 2c not in straight lines with sharp break points, but rounded at the transition points).
   • Delay a _neg ,
   • Cycle time of the task t _cycle .
2. 2. Evaluation of the braking distance and possible correction with default values as default values of plausibility or speed (eg for very small paths).
3. 3. Calculation of the distance traveled during the calculation and linking with the minimum braking distance Δs taking into account all relevant motion parameters, namely the current speed v and the number of task cycles during the calculation. The process of stopping takes place in the range of milliseconds, so that even the time for calculating the stop signal must be included in the calculation itself.
4. 4. Calculation of the absolute stop position taking into account the calculated braking distance and the desired stop position (depending on the stop event) in the master axis cycle.
5. 5. Specifying and starting an absolute movement of the virtual master axis to the calculated stop position of the master axis with the determined motion parameters.

Subsequently, in the interrogation stage A3, the determination of an existing slip occurs, as may be present in a belt drive of the knitting tools.

If, however, the query in query step A2 revealed that an undefined stop position should be reached, signal 4 activates the computing state B3, in which the stop command to the master axis is formed as the relevant stop signal. The signal 5 causes the stop of the master axis C undefined with the calculated stop parameters.

If the polling stage A3 determines that the system is not subject to slip, then the standstill of the master axis C is also effected by means of the signal 6, but in this case with a defined stop position. In the presence of slip, however, the signal 7 is sent to the computing stage B4. In this a correction for the slip is calculated shortly before reaching the stop position. The calculation is based on the current position and the stop position. As soon as the correction calculation is completed, a corrected absolute movement of the master axis is specified and calculated. Via the signal 8, the stop position of the master axis is reached at C in this case. With the absolute movement of the master axis, the time span from the detection of the stop event to the standstill of the virtual master axis is calculated. But it can also be expected with a relative movement of the leading axis, which corresponds to the position of the virtual master axis after completion of the calculations and also leads to a targeted stop position.

Claims (10)

1. Method of stopping a warp knitting machine, the components of which are operated in a manner coordinated with one another in accordance with signals from a moving master shaft (C), the stopping procedure being initiated by one-off triggering of a stop event (SE1, SE2, ... SE5), and the one-off triggering of the stop event (SE1, SE2, ... SE5) leading to controlled retardation of the master shaft movement in a sequence down to a standstill leading to a defined stop position (S1, S2, ... S5) of one or more of the components,
   characterized in that, following the triggering of the stop event (SE1, SE2, ... SE5), the following measures are carried out:

   a) in accordance with the movement relationships present, a stop time (t_s) appropriate to the triggering stop event (SE1, SE2, ... SE5) and the associated braking travel (Δs) are determined;

   b) an intermediate position (SB1, SB2, ... SB5) of the master shaft (C) is determined, which is at a distance from the intended position (S1, S2, ... S5) of its stoppage by the amount of the braking travel (Δs) determined;

   c) when the master shaft reaches the determined intermediate position (SB1, SB2, ... SB5), it triggers a phase of the controlled, active slowing of the master shaft movement;

   d) the phase of the controlled, active slowing ends after the braking travel (Δs) determined has been covered, with the stoppage of the master shaft (C) in the intended position (S1, S2, ... S5), which brings about a defined stop position of one or more of the components.
2. Method according to Claim 1, characterized in that the master shaft (C) used is the drive shaft of a central main drive motor.
3. Method according to Claim 1, characterized in that the master shaft (C) used is the main shaft of the warp knitting machine.
4. Method according to Claim 1, characterized in that, in the case of a computer-controlled warp knitting machine having individual drives of the components, the master shaft (C) is a virtual master shaft formed by the software of the computer.
5. Method according to Claim 4, characterized in that the servomotors of the components are position-controlled by displacement signals from the master shaft (C).
6. Method according to one of Claims 1 to 5, characterized in that, when stopping a warp knitting machine the drive of which is affected by slippage, an additional signal which takes the slippage into account shortly before reaching the stop position (S1, S2, ... S5) is formed and introduced into the method.
7. Method according to one of Claims 1 to 6, characterized in that the stoppage position (S1, S2, ... S5) of the master shaft (C) is determined as a point at which a plurality of components at the same time reach a stop position specifically defined for them.
8. Method according to one of Claims 4 to 7, characterized in that, in the phase of the controlled, active slowing of the master shaft movement, the common coupling of the actuating motors driving the components to the master shaft (C) is cancelled and individual control of the components is carried out.
9. Method according to one of Claims 1 to 8, characterized in that when the warp knitting machine is at a standstill, in the case of the critical components, a defined stop position window is achieved instead of a defined stop position.
10. Method according to one of Claims 1 to 9, characterized in that, in the phase of the active slowing, the predefined stoppage position (S1, S2, ... S5) of the master shaft (C) is corrected when a new stop event is input.

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