Title of Invention

THREAD DISPLACEMENT DRIVE, IN PARTICULAR FOR A WORKSTATION OF A TEXTILE MACHINE

Abstract

The invention relates to a mechanism for controlling a thread displacement, in particular for a  textile machine working station comprising a thread guide and an electric  motor individual  drive  provided  therefor  and  an  angle  sensor  for determining an actual angular position (11) (f_real) of a thread guide and a controller (4) for predefining at least one correcting variable (9) (u) for the output stage of the electric motor individual drive for driving the thread. The inventive mechanism for controlling a thread displacement makes it possible to obtain high displacing frequencies by preventing displacement errors, wherein the controller (4) comprises a multivariable control system for accurately controlling at least  one correcting variable (9) (u), and thereby the actual angular position (11) (f_real) of the thread guide.  A status monitor (12) for accurately determining the internal conditions such as in a real control section (10) and for transmitting them to the controller is provided.

Full Text

FORM 2 THE PATENT ACT 1970 (39 of 1970) The Patents Rules, 2003 COMPLETE SPECIFICATION (See Section 10, and rule 13) 1. TITLE OF INVENTION THREAD DISPLACEMENT DRIVE, IN PARTICULAR FOR A WORKSTATION OF A TEXTILE MACHINE 2. APPLICANT(S) a) Name b) Nationality c) Address OERLIKON TEXTILE GMBH & CO. KG GERMAN Company LANDGRAFENSTRASSE-45 , D-410 69 MOENCHENGLADBACH, GERMANY 3. PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed : - Description Thread displacement drive, in particular for a workstation of a textile machine The invention relates to a thread displacement drive, in particular for a workstation of a textile machine according to the preamble of claim 1. In order to produce a textile bobbin, it is known for example from the document DE 198 58 548 Al, on the one hand, to make the relevant textile bobbin rotate and, on the other hand, to traverse the thread running onto the bobbin along the bobbin axis. The traversing of the thread takes place, for example, with the aid of a finger thread guide which is also called a wiper. So that a special or predetermined winding structure can be produced in the bobbin to be produced, the drive of the bobbin must be separated from the drive of the thread guide. By means of this uncoupling of the drives required a precision or step precision windings can be produced. This technical measure therefore means that winding patterns are avoided on the bobbin which can lead to considerable problems during later unwinding. Textile bobbins of this type with a so-called cross-winding are therefore not only distinguished by a comparatively stable bobbin body, but also by good run-off behaviour. By using a thread guide known from the document DE 198 58 548 Al, which is provided with an electromagnetic drive, a qualitatively high-value cross-winding of a textile bobbin can be produced by relatively rapid and precise traversing of the thread. The use of the finger-like thread guide allows - from a purely mechanical point of view - thread displacement frequencies of more than 30 Hz. As, however, high acceleration values act at the reversal points of the thread guide and an overshoot is easily caused at the reversal points owing to the mass inertia of the thread guide, the drive of the thread guide has to be precisely activated or controlled to avoid thread displacement errors. The open-loop and closed-loop control systems known from the prior art are only in a position to achieve a precise drive of the thread guide at low thread displacement frequencies. Consequently, the technical possibilities of the thread guide can only be exploited to a limited extent, and this as a whole affects the winding speeds of the corresponding winding station and therefore also the productivity of the textile machine. In the non-prior publication DE 103 54 587 Al, a special angle sensor is described for the already described thread guide or wiper. Owing to this angle sensor, which inter alia consists of an analogue Hall sensor and a magnet, the actual angular position of the thread guide is detected and passed to an open-loop or closed-loop control system, not described in more detail, of the thread guide drive for further processing. Although the actual angular position of the thread guide can be rapidly and precisely determined by the angle sensor disclosed, nevertheless the above-mentioned problem of the previously used open-loop or closed-loop control systems is not solved thereby. WO 99/05055 A describes a method and a traversing device for displacing a thread. In this case, the traversing thread guide is moved by means of an electric motor, the desired position of the traversing thread guide being determined by a position of the electric motor. The actual position of the traversing thread guide is detected continuously by means of a measuring device and supplied to a control device, which carries out a desired/ actual comparison of the position of the traversing thread guide and generates a corresponding differential signal to control the electric motor. The electric motor can be controlled by means of amplitude. When there is a deviation between the actual position and the desired position, the electric motor receives through the differential signal a current which is changed with respect to its amplitude. Thus, the positioning of the traversing thread guide can be implemented with great precision in particular in the reversal region. Proceeding from the prior art mentioned above, it is therefore the object of the present invention to provide a thread displacement drive with a thread guide, which allows high displacement frequencies while avoiding thread displacement errors. In the process, the technical structure present or the configuration should be utilised as far as possible. To achieve this object, a thread displacement drive with the features of claim 1 is proposed. Advantageous developments of the thread displacement drive according to the invention are listed in the sub-claims 2 to 10. The necessary displacement curve for the thread guide, consisting of the respective angular positions can be calculated using the predetermined winding structure. The thread guide has to precisely follow this displacement curve. It is provided according to the invention that, for this purpose, the controller comprises a multivariable control system, in order to precisely control the angular position (j_actual) of the thread guide by means of the at least one control variable (u) for the real control section. The output stage and the electromechanical displacement drive of the thread guide form the real or actual control section. By using a multivariable control system, the desired precise control for positioning the thread guide at the required thread displacement frequencies can therefore be achieved. The subject of the invention is advantageously set up to generate at least one non-measured input variable in addition to the at least one measured input variable of the controller. In order to provide further input variables for the multivariable control system of the controller, it is provided that, apart from the predetermined angular position (j_desired) of the thread guide, a plurality of input variables such as the corresponding moment (M_desired), the corresponding angular acceleration (w_point_desired), the corresponding angular speed (w_desired) as well as the current (I_desired) required for displacement for the drive of the thread guide are also entered as desired variables. Thus, information on the moment (M_desired), the angular acceleration (w_point_desired), the angular speed (w_desired) and the necessary drive current (I_desired) is also available for the controller at each angular position((j_desired) of the thread guide. Because of the precalculated displacement curve, the control system or the controller can thus prevent an overshoot of the thread guide at the reversal points of the bobbins as well as other displacement errors at high thread displacement speeds. This obviously only applies for as long as no disturbance variables occur. So that, apart from the desired variable of the angular position (j_desired), the desired values of the moment (M_desired), the angular acceleration (w_point_desired), the angular speed (w_desired) and the displacement current (I_desired) do not have to be additionally provided for each displacement curve of a winding structure, the missing variables for the ideal control section are calculated by means of a section model, which simulates the real control section by control technology or mathematically, from the respective angular positions (j_desired). In this case, the desired variable of the angular position ((j_desired), on the one hand, directly enters the controller and, on the other hand, in parallel enters the section model of the ideal control section. The moment (M_desired) corresponding to the respective angular position ((j_desired), the corresponding angular acceleration (w_point_desired), the corresponding angular speed (w_desired) and the necessary displacement current (I_desired), are determined with the aid of the ideal control section and, as output variables of the section model, enter the controller as further desired variables for the multivariable control. The comparable actual values, which consist of the actual angular position (j_actual) of the thread guide, the current moment (M_actual), the current angular acceleration (w_point_actual), the current angular speed (w_actual) of the thread guide as well as the available displacement current (I_actual), to the entering desired values are also expediently available to the controller. As in practice a series of disturbance variable acts on the actual control section, the control system also requires the actual values of these variables to be able to compensate a deviation of the actual values from the desired values. These actual values may, for example, be detected directly by additional sensors or measuring detectors or indirectly calculated with the aid of other physically detectable measured variables and passed to the controller by means of a feedback. Nevertheless, the exact measurement of the torque designated moment as well as of the current in the thread displacement drive (I_acrual) is technically very laborious and expensive. The angular speed and the angular acceleration could be generated by the derivation of the signal, which the angle sensor supplies. As the control system should advantageously be digitised to convert the calculations in a microprocessor, a very noisy signal is produced by the derivation of a digital value. So this signal can be used, filtering would be unavoidable. However, this would result in a large loss of dynamics. Therefore, a further measure improving the invention provides that the comparable actual values (to the desired values of the controller) after the real control section can be determined by a status observer as so-called estimate values (j_top, M_top, w_point_top, w_top, I_top) and passed to the controller (by the already mentioned feedback), at least one control variable (u) of the controller and the actual angular position ((j_actual) being available as input variables for the status observer. The status observer itself is a further time-invariant model, by which the desired actual values can be reconstructed. Although the values obtained from the status observer are called "estimate values", these are not in any way "estimated values", but precisely determined and calculated values. In other words, the connected observer allows the inner states, such as are present in the real control section, to be determined with adequate accuracy and to be provided to the controller. Owing to this measure, the above-described, additional sensors can be dispensed with as only the actual value of the angular position (j_actual) is detected with the already available angle sensor. Consequently, the above-mentioned disadvantages of the additional measuring sensors can also be prevented by the status observer used. Therefore, the existing technical structure or the configuration of the thread displacement drive can be reverted to. In a further preferred embodiment, the status observer is configured as a Luenberger observer or else as a so-called asymptotic observer. Reference is made with regard to the Luenberger observer, for example, to Otto Follinger "Regelungstechnik" (control technology), Dr. Alfred Huthig Verlag Heidelberg 1990. On pages 502 et seq. of the Book it is explained in more detail how the observer parameters are determined and how an observer is designed by means of complex transmission functions for a single variable system or multivariable system, as in the present case. The proposed Luenberger observer has the advantage that the system state can be precisely reconstructed again after an initial disturbance with the aid thereof. This applies in particular for disturbances, which are repeated from time to time, as the observer is in a position to again detect the new system state. Consequently, the use of the Luenberger observer allows the thread displacement drive to be precisely controlled even in the case of possible disturbances. Expediently, a weighting of the individual desired and actual values is provided in the controller by weighting components, separated from one another in each case, so the control quality of the controller can additionally be improved in a simple manner. The respective weighting of the individual values can be determined experimentally, for example. Furthermore, it may be advantageous for it to be possible for the individual desired and actual values to not only be weighted in a linear manner, but also potentially or exponentially by the weighting components. As already described in the section above, this measure can also further raise the quality of control in a simple manner. The control differences of the individual desired/actual values may be detectable by the controller, for example after a weighting has been carried out, and the controller may carry out a correction of at least one control variable (u) in a control difference which does not equal zero. It is therefore possible to reproduce a control algorithm by means of the proposed controller, which carries out a desired/actual comparison of the control variables used in a possible weighting of the individual variables and redetermines or recalculates at least one control variable (u), if there is a control difference. In a further alternative embodiment of the invention, an angle sensor is used to detect the actual angular position (j_actual) of the thread guide and has an analogue Hall sensor and a magnet, in particular a permanent magnet, which are in operative connection with one another. More details and application examples can be inferred from DE 103 54 587 Al. Obviously, however, instead of the analogue Hall sensor, an optical (digital) angle sensor may also be used to detect the actual angular position (j_actual) of the thread guide. A calculator (microprocessor or computer), which simulates at least the section model and/or the status observer using control technology or mathematically, allows the present invention to be implemented economically and simply. If a computer of this type is used, it can also be used for the controller. The technical construction of the invention can thus be further simplified and additional costs saved. In order to optimise the efficiency of a textile machine, which is used to provide bobbins and is equipped with the thread displacement drive according to the invention, all the workstations present are equipped with the thread displacement drive according to the invention. The invention allows high thread displacement frequencies while avoiding displacement errors. As far as possible the existing technical structures of the thread displacement drive are used. The angular position (j_desired) advantageously enters the controller directly as a desired value, on the one hand, and, on the other hand, as an input variable for a section model connected upstream, which simulates the real control section by control technology or mathematically. Owing to this section model connected upstream, further desired values, such as, for example, the angular speed (w_desired) corresponding to the angular position, the corresponding moment (M_desired), the corresponding angular acceleration (w_point_desired) and the necessary displacement current (I_desired) are determined for a multivariable control of the controller. Thus, a precise and rapid control of the thread displacement drive is made possible, as long as no disturbance variables occur in the system. As, unfortunately, disturbance variables can never completely be ruled out in practice, it is advantageously provided while retaining the existing technical structures of the thread displacement drive, that by means of a status observer, the angular position (j_top) of the thread guide, the corresponding angular speed (w_top) of the thread guide, the corresponding moment (M_top), the corresponding angular acceleration (w_point_top) and the current (I_top) of the drive necessary for the displacement are generated as estimate values from the control variable (u) of the controller and the actual angular position (j_actual) and are available to the controller as further input variables (by a feedback). Thus the control system also reacts to possible disturbances, which are therefore compensated. All five input variables are not required in every case for the control. For example, three input variables for control according to the invention may be sensible, such as the angular position, the, angular speed and the current. However, it is also possible to use more than five input variables for the control. The more input variables are entered, the greater is the control precision that is achievable. However, the outlay for control increases with an increasing number of input variables. Further advantages, features and details of the invention emerge from the following description and the drawing with respect to an embodiment of the invention. In this case, the features mentioned in the claims and in the description may be fundamental to the invention on their own or in any combination. In the drawing: Fig. 1 shows a block diagram with regard to the exemplary control structure of the thread displacement drive. Fig. 1 shows a block diagram with regard to the control structure of the thread displacement drive with a status observer 12. In this case, from the desired value sensor 1, the predetermined angular position ((j_desired) enters the controller 4 directly as the desired variable 2. This angular position (j_desired) is also used as an input variable for the section model 3. By means of the section model 3, the real control section 10, which consists of the output stage of the thread guide drive and the further electromechanical thread displacement drive, is depicted as the ideal control section. Thus, the further desired variables 2, namely the corresponding moment (M_desired), the required displacement current (I_desired), the corresponding angular speed (w_desired) and the corresponding angular acceleration (w_point_desired) of the thread guide, can thus be generated as additional input variables for the controller 4. In the controller 4, a weighting of the desired variables 2 being entered may be provided individually by weighting components 5 separately for each desired variable 2. So the controller 4 can also react to possible disturbance variables 14, which act on the real control section 10, actual values, which are present at the end of the real control section 10, are also entered as a basis for a comparison with the desired values 2. For this purpose, the actual values are fed back to the controller 4. In the present case, however, the desired actual values are supplied as estimate values 13 from a status observer 12 to the controller 4, as the actual values present can only be determined with a disproportionate outlay. The status observer 12 namely allows, using the control variable 9 (u), which represents a voltage, and the control variable 11, which consists of the actual angular position 11 (j_actual) of the thread guide, the comparable estimate values 13 to the required actual values to be determined. These actual values consist of the actual angular position 11 (j_actual), the associated moment (M_actual), the associated angular speed (w_actual) of the thread guide, the associated angular acceleration (w_point_actual) and the actual displacement current (I_actual). Accordingly, the status observer 12 supplies the estimate values 13 of the angular position 11 ((j_top), the associated torque (M_top), the associated angular speed (w_top) of the thread guide, the associated angular acceleration (w_point_top), and a displacement current (I_top). By using the status observer 12 the technical structure or configuration of the thread displacement drive subsequently does not need to be changed. The estimate values 13 determined by the status observer 12, as already mentioned, enter the controller 4 as further variables. Thus, a determination of a plurality of various actual values by measuring at the end of the real control section 10 can be dispensed with. Furthermore, a weighting of the fed back estimate variables 13 in the controller 4 may take place owing to existing weighting components 6. The variables resulting therefrom are processed in computer units 7 and compared with the also weighted desired variables 2 by means of a desired/actual comparison 8. The comparison of the desired/actual values generally takes place by calculations of the difference. If the result should differ from zero, the controller will carry out a correction of at least one control variable 9 (u) for the real control section 10. This means that the thread guide reaches it predetermined angular position (j_desired) again. The control variables 9 (u) output by the controller 4 are passed to the real control section 10, so the angular position of the thread guide is changed. The actual angular position 11 (j_actual) of the thread guide is detected by an angle sensor, not shown, and is the actual control variable 11 of the control system depicted. This control variable 11 is the only actually determined actual value of the entire control system. As already mentioned above, it is also conceivable for the required actual values to be detected by additional sensors or measurement detectors and passed to the controller 4 via a feedback. List of reference numerals 1 desired value sensor 2 desired variables/values 3 section model with ideal control section 4 controller 5 weighting components for weighting the desired values 6 weighting components for weighting the actual or estimate values 7 computer unit 8 desired/ actual comparison 9 control variable 10 real or actual control section (output stage + electromechanical thread displacement drive) 11 actual value/control variable 12 observer 13 estimate value 14 disturbance variable WE CLAIM: 1. Thread displacement drive, in particular for a workstation of a textile machine, comprising a thread guide and an electric motor single drive provided for this and an angle sensor for detecting the actual angular position (j_actual) of the thread guide and a controller (4), by means of which at least one control variable (9) (u) for an output stage of the electric motor single drive can be predetermined, to drive the thread guide, characterised in that the controller (4) comprises a mulrivariable control system to precisely control the angular position (j_desired) of the thread guide by means of at least one control variable (9)(u) and in that a plurality of the following input variables i) the predetermined angular position (j_desired) of the thread guide, ii) the corresponding moment (M_desired) of the thread guide, iii) the corresponding angular acceleration (w_point_desired) of the thread guide, ((j_desired) iv) the corresponding angular speed (w_desired) of the thread guide, and v) the current (I_desired) necessary for displacement of the drive enter the controller (4) as desired values (2). 2. Thread displacement drive (1) according to claim 1, characterised in that a section model (3) is present, which simulates the control section (10) (current output stage + drive of the thread displacement system) and predetermines a plurality of the further input variables of the controller (4) of the thread guide from the predetermined angular position (j_desired). 3. Thread displacement drive (1) according to claim 1 or 2 characterised in that after the control section (10) a feedback is present, which provides the controller (4) with comparable actual values to the desired values (2). 4. Thread displacement drive (1) according to any one of claims 1 to 3, characterised in that the comparable actual values to the desired values (2) after the control section (10) can be determined as so-called estimate values (13) by a status observer (12) and are available to the controller (4), and at least one control variable (9) (u) and the actual angular position (11) (j_desired) are used as input variables for the status observer (12). 5. Thread displacement drive (1) according to claim 4, characterised in that the estimate values (13) generated by the status observer (12) comprise i) the predetermined angular position (j_top) of the thread guide, ii) the corresponding moment (M_top) of the thread guide, iii) the corresponding angular acceleration (w_point_top) of the thread guide, (j_top) iv) the corresponding angular speed (w_top) of the thread guide, and v) the current (I_top) necessary for displacement of the drive. 6. Thread displacement drive (1) according to claim 4 or 5, characterised in that the status observer (12) is a Luenberger observer. 7. Thread displacement drive (1) according to any one of claims 1 to 6, characterised in that, in the controller (4), a weighting of the individual desired and actual values by weighting components (5, 6), separately form one another in each case, is provided. 8. Thread displacement drive (1) according to claim 7, characterised in that the weighting components (5, 6) comprise a linear, potential or exponential weighting of the individual desired and actual values. 9. Thread displacement drive (1) according to any one of claims 1 to 8, characterised in that the angle sensor for detecting the actual angular position (11) (cp_actual) of the thread guide has an analogue Hall sensor and a magnet, in particular a permanent magnet, which are in operative connection with one another. Dated this 19th day of November 2007 ABSTRACT The invention relates to a mechanism for controlling a thread displacement, in particular for a textile machine working station comprising a thread guide and an electric motor individual drive provided therefor and an angle sensor for determining an actual angular position (11) (f_real) of a thread guide and a controller (4) for predefining at least one correcting variable (9) (u) for the output stage of the electric motor individual drive for driving the thread. The inventive mechanism for controlling a thread displacement makes it possible to obtain high displacing frequencies by preventing displacement errors, wherein the controller (4) comprises a multivariable control system for accurately controlling at least one correcting variable (9) (u), and thereby the actual angular position (11) (f_real) of the thread guide. A status monitor (12) for accurately determining the internal conditions such as in a real control section (10) and for transmitting them to the controller is provided.

Documents:

1939-mumnp-2007-abstract(18-1-2010).pdf

1939-mumnp-2007-abstract.doc

1939-mumnp-2007-abstract.pdf

1939-mumnp-2007-cancelled pages(18-1-2010).pdf

1939-mumnp-2007-claims(18-1-2010).pdf

1939-MUMNP-2007-CLAIMS(AMENDED)-(18-1-2010).pdf

1939-mumnp-2007-claims.doc

1939-mumnp-2007-claims.pdf

1939-MUMNP-2007-CORRESPONDENCE(18-1-2010).pdf

1939-mumnp-2007-correspondence(ipo)-(3-11-2009).pdf

1939-mumnp-2007-correspondence-others.pdf

1939-mumnp-2007-correspondence-received.pdf

1939-mumnp-2007-description (complete).pdf

1939-MUMNP-2007-DESCRIPTION(COMPLETE)-(18-1-2010).pdf

1939-mumnp-2007-drawing(18-1-2010).pdf

1939-mumnp-2007-drawings.pdf

1939-mumnp-2007-form 1(14-12-2007).pdf

1939-mumnp-2007-form 2(18-1-2010).pdf

1939-mumnp-2007-form 2(title page)-(18-1-2010).pdf

1939-MUMNP-2007-FORM 3(18-1-2010).pdf

1939-mumnp-2007-form-1.pdf

1939-mumnp-2007-form-18.pdf

1939-mumnp-2007-form-2.doc

1939-mumnp-2007-form-2.pdf

1939-mumnp-2007-form-26.pdf

1939-mumnp-2007-form-3.pdf

1939-mumnp-2007-form-5.pdf

1939-MUMNP-2007-FORM-IPEA-409(18-1-2010).pdf

1939-mumnp-2007-form-pct-ib-306.pdf

1939-mumnp-2007-form-pct-ipea-416.pdf

1939-mumnp-2007-pct-search report.pdf

1939-MUMNP-2007-PETITION UNDER RULE 137(18-1-2010).pdf

1939-MUMNP-2007-REPLY TO EXAMINATION REPORT(18-1-2010).pdf

1939-mumnp-2007-specification(amanded)-(18-1-2010).pdf

1939-MUMNP-2007-SPECIFICATION(AMENDED)-(18-1-2010).pdf

1939-mumnp-2007-wo international publication report(14-12-2007).pdf

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