Method and apparatus for controlling the winding of threads and the like onto rotating supports such as reels of yarn and the like

Description

[0001] The present invention relates to a method and an associated apparatus for controlling the winding of threads and the like onto rotating supports such as reels for weaving and the like.

[0002] It is known that in the weaving industry every process which is performed using thread results in the need to store the said thread so that it is available in the most convenient form for subsequent operations.

[0003] One of the most common and widely used forms of storage consists of the so-called reel, namely a cylindrical element onto which the thread is wound so as to produce a spool (or reel) which must have precisely determined characteristics - such as the diameter, weight, shape, unwinding precision and speed - which are those used for defining the greater or lesser adaptability of a certain type of reel for subsequent processing which may require a high unwinding speed or an unwinding tension which is as small as possible, or a uniform density or high volume.

[0004] It is also known how said characteristics are substantially determined by the reel winding methods and conditions, said winding having to be, however, as fast and precise as possible.

[0005] Said winding is essentially performed by fastening one end of a thread to a cylinder supporting the reel and by causing rotation of the said cylinder by means of a controlled motor; the thread is simultaneously inserted into a guiding element (thread guide) which is actuated so as to perform an alternating rectilinear movement with a trajectory parallel to the axis of the cylinder.

[0006] It is also known that winding of the thread onto the reel produces two main control-related problems arising from:

• the need to keep the time required for reversing the movement of the thread guide as small as possible so as to achieve the highest possible winding speed and
• the need to ensure the maximum precision of the thread reversal point, namely the point where the thread completes an outward winding cycle and starts the return winding cycle; control of the reversal position is of critical importance for preventing separation of the thread from the reel or, vice versa, overlaying of the thread (ribbing), which are the direct cause of breakage of the thread and/or incorrect unwinding of the reel during subsequent processing.

[0007] In order to achieve control of the two abovementioned parameters, solutions based on the use of stepper motors have been proposed, said motors being operated by means of controlled and programmed sequences of pulses which, varying in frequency, perform slowing down and reversal of the movement of the thread guide as well as compensation of any errors in the reversal point.

[0008] This technique is known, for example, from EP 0,453,622.

[0009] Although fulfilling their function, these solutions, however, have certain drawbacks arising from the use of pulse-controlled stepper motors which, since there is no bi-univocal correspondence between the stator current and the torque produced, generate pulsating torques which are the cause of electrical and mechanical resonance which arise at given frequencies, producing stoppage of the motor and, at the same time, causing loss of all the information relating to the position of the thread guide, said information having to be subsequently restored.

[0010] In order to eliminate these problems, common practice envisages using only 70% of the motor's rated power during winding of the thread and keeping the remaining 30% available for overcoming the said blockage points as quickly as possible.

[0011] The use of only 70% of the available power, however, reduces the possibility of obtaining the high accelerations (braking torque) which are necessary for reducing the time required for reversing the movement of the thread guide. Moreover, the use of a pulse-control system, which depends solely on the frequency of the said pulses, requires that the current which is supplied to the motor must be kept at a value higher than that which would actually be necessary, since an excessive reduction in the said current would not leave a safety margin for preventing loss of the step sequence and consequent stoppage of the apparatus, should there be random increases in the resistance torque due, for example, to the irregular nature of the thread.

[0012] The technical problem which is posed, therefore, is that of providing a method and an associated apparatus for controlling devices for guiding and laying yarns and the like to be wound onto cylindrical supports for forming a reel, which are able to minimize the time required for reversing the direction of movement of the thread guide, thereby overcoming the abovementioned problems associated with pulse-controlled stepper motors.

[0013] Within the scope of this problem a further requirement is that the method and the associated apparatus should be able to control with a high degree of repeatability the precision of the thread winding reversal point and that this control should be such as to allow easy and rapid variation of the associated parameters in relation to the different types of winding required.

[0014] These technical problems are solved according to the present invention by an apparatus for controlling the alternating movement of a thread guide which is actuated by an electric motor via means supporting the said thread guide and is intended to wind a thread onto rotating supports, comprising an angular transducer for detecting the angular position of the rotor of the motor, a device for vectorial control of the currents supplied to the motor, and a circuit for controlling the speed of rotation of the rotor, which is connected to the angular transducer and to the vector control circuit.

[0015] The present invention also relates to a method for controlling the alternating movement of a thread guide which is actuated by an electric motor via means supporting the said thread guide and is intended to wind a thread onto rotating supports, comprising the steps of detecting the angular position of the rotor of the motor, sending corresponding signals to a circuit controlling the currents supplied to the motor and to a circuit controlling the speed of the thread guide, vectorial control of the currents supplied to the motor and control of the speed of the thread guide.

[0016] Further details may be obtained from the following description of a non-limiting example of an embodiment of the invention, provided with reference to the accompanying drawings in which:

• Figure 1 shows the diagram of a first embodiment of the apparatus for winding yarns with associated means for controlling the speed of the thread guide;
• Figure 2 shows the detailed diagram of the circuit for vectorial control of the motor;
• Figures 3a,3b show a linear representation of the movement of the thread guide and the signals for controlling the speed alone;
• Figure 4 shows the diagram of a further embodiment of the apparatus according to the invention with control of the speed of rotation and position for reversal of the thread guide movement;
• Figures 5a,5b show a linear representation of the movement of the thread guide and the signals controlling the speed and the position of the thread guide.

[0017] As illustrated in Fig. 1, a spooling machine of the known type essentially comprises a spool or reel 1 which is rotationally driven by a motor 2, optionally via a drive roller (not shown), and a thread guiding device comprising a second motor 4 (in the example of the two-phase type) which is independent of the first motor and connected to a first pulley 5a of the thread guiding device 5 which also comprises a second pulley 5b and a belt 6 endlessly wound around said pulleys and supporting the cursor 6a through which the thread 7 passes.

[0018] The motor 4 is of the multiple-pole type and may be of the stepper type or so-called brushless type.

[0019] The rotational operation, in both directions, of the pulley 5a - and therefore the belt 6 - causes the alternating linear movement of the cursor 6a and consequently the outward/return cycle of the thread which is wound onto the reel.

[0020] Said alternating movement (Fig. 3a) is performed between two ends (reversal points) X0 and X3 which are chosen according to the programmed winding parameters and determined with reference to a predefined "absolute zero" position of the machine; as shown in Figs. 1 and 3a, in a preferred embodiment, said reversal points are both on the same side with respect to the said absolute zero Z0 which forms the reference point for the entire machine.

[0021] In the example shown, said absolute zero consists of a mechanical stop (or position sensor) 8 which is arranged beyond the right-hand reversal position for winding of the thread 7.

[0022] The apparatus 100 for controlling winding comprises a first detection device consisting of an angular transducer 110 which in the example is formed by an incremental encoder and is able to detect the angular position of the rotor 4a of the motor 4 and send corresponding electric signals to a circuit 120 for vectorial control of the currents supplied to the stator 4b of the motor 4; the same signals of the encoder 110 are also sent to a circuit 130 for controlling the speed of rotation of the motor 4.

[0023] In greater detail, the circuit 120 for vectorial control of the currents comprises:

• a circular counter 121 which, for example, is dimensionally designed so as to count sixty four pulses per revolution and which:
  • receives at its input a signal 110b which is emitted by the encoder 110 in relation to the angular position of the rotor 4a;
  • and emits at its output a signal 121b corresponding to angular values α which represent the angular position of the rotor and increase/decrease in relation to the direction of rotation of the rotor and which are sent:
• to a block 122 for converting said values of α into corresponding cyclically repeated sine and cos values of α able to send corresponding signals 122b;
• to a first input of a pair of multipliers 123 which receive at a second input a signal 135b emitted by the speed control device 135; said multipliers therefore determine the value of the modulus of the two vectors of the current supplied to the respective stator windings;
• a switch 124 which is able to assume two positions A and B respectively for normal continuous control and initial phase synchronization, respectively, (described in detail below) and the outputs 124b of which are supplied to:
• a power circuit 125 for supplying the currents to the motor 4.

[0024] As mentioned, by means of the vector control circuit 120 it is possible to perform also initial phase synchronization of the device suitable for determining output, by the motor, of the maximum available torque for each angular position of the rotor.

[0025] Said phase synchronization of the maximum torque is obtained by ensuring that the vector representing the vectorial sum of the stator magnetic fields is always perpendicular to the vector of the rotor magnetic field.

[0026] Essentially (Fig. 2), whenever the machine is switched on, it is required to define an angle between the two fields such as to determine the maximum torque operating condition; for this purpose:

• the switches 124 are switched to position B where:
• the maximum current value is defined in the stator winding 4c and
• the current value in the stator winding 4d is zeroed;
• in these conditions, after a few fractions of a second, the rotor is aligned with the maximum current winding,
• and it is possible to set the counter 121 to the numerical value (16, if the counter is a 64-pulse counter) corresponding to an angle α which is phase-displaced by 90° with respect to the existing alignment position; in this way the counter 121 will output signals corresponding to the detected angular value displaced by +90°, imposing this angular phase displacement for each point of rotation of the motor, in order to maintain the desired maximum torque condition;
• once phase synchronization has been obtained, the currents are reset to zero and the switch 124 is again switched to position A in order to start normal control of the winding cycle.

[0027] In the case of motors with more than two phases, a similar procedure is adopted, taking into account the angular position of the resultant of the stator field. It is also envisaged that initial phase synchronization may alternatively be implemented by means of control of the counter 121 - or its output 121b - performed by the calculation unit 133.

[0028] The circuit 130 controlling the speed of the rotor 4a - and therefore that of the thread guide 6a - is, as mentioned, based on the encoder 110 and comprises:

• a device 134 for detecting the direction of movement of the rotor 4a which, depending on the sequence of signals 110b sent to its input by the encoder 110, is able to emit a signal 134b representing the direction of rotation of the rotor - and hence the direction of movement of the thread guide 6a - which is sent to a first input of:
• a counter 131
  • which receives at a second input the pulses 110b which are emitted by the encoder 110 and are counted and stored so as to generate a counting signal 131b representing the existing position of the rotor 4a and therefore that of the thread guide 6a;
  • an existing position comparator 132 which receives at its input:
  • the signal 131b emitted by the counter 131,
  • the signal 134b emitted by the direction of movement detector 134,
  • two signals 141b and 142b emitted by a pair of calculation units 141,142 associated with the central processing unit 133 and representing the calculated position of the points X2,X5 where it is required to reverse the torque,
• emits a corresponding signal 132b which represents the direction of the torque required for that unwinding section and which is sent to the register 122 of the vector conversion circuit 120.

[0029] At the same time, the signal 110b of the encoder 110 is also sent to the speed control and regulation device 135 which, receiving at its input:

• also a signal 133c emitted by the unit 133 and representing the speed programmed for the specific winding section,

emits a current signal 135b corresponding to the torque value required in order to reach and maintain the intended speed along the existing trajectory section.

[0030] In this way the vector conversion circuit is able to control both the modulus and the direction of the torque which must be output by the motor 4 in order to obtain the speed value of the thread guide required for the specific situation along the travel path of the said thread guide.

[0031] Since the encoder 110 is of the incremental type, all the control is also of the incremental (i.e. non-absolute) type and, whenever the machine is switched off, memorization of the position of the thread guide 6a with respect to the absolute zero 8 of the machine is lost, said memory having consequently to be restored whenever the apparatus is switched on.

[0032] For this purpose, the counter 131 is set, at each switch-on, using the following procedure:

• a small torque and speed value are set by means of a limiting device 136 in order to prevent mechanical damage to the thread guide when it comes into contact with the mechanical stop 8;
• the thread guide is displaced until it stops in abutment against the absolute-zero mechanical stop 8,
• after lapsing of a certain predefined maximum time interval - or alternatively when there is the prolonged absence of pulses from the encoder 110 - a signal indicating that stoppage has occurred is sent to the central control unit 133 which, in turn, resets the counter 131, restoring the reference value of the apparatus,
• from this moment the sequence of pulses 110b emitted by the encoder 110 determines the location of the existing position and the direction of displacement of the thread guide 6a.

[0033] In the exemplary case of reversal points arranged on the same side with respect to the absolute zero, in order to start the actual spooling cycle, the direction of movement of the thread guide is reversed, checking that the value of the counter 131 is equal to the value 133b programmed to start winding and sent to the counter:

• for as long as the two values are different, the thread guide continues to advance and the motor maintains a certain torque value;
• when the two values are the same (starting point reached), the torque is reduced to zero and the signal for starting spooling is awaited.

[0034] Since the speed of the thread guide and the presence of unpredictable variables such as friction, tension, vibration and the like affect operation of the machine such that the thread guide reverses its travel movement not exactly at the predefined points X0,X3, but at points which may be before (negative error or underestimation) or after (positive error or overestimation) these programmed points X0,X3, the operating and control apparatus 100 also comprises a circuit 140 for correcting said reversal error.

[0035] Said circuit 140 comprises:

• a device 145 for measuring the error in travel through the reversal point,
• a pair of corresponding storage units 143,144 designed to store the respective the right-hand or left-hand error which has occurred during winding.

[0036] In greater detail, the error measuring device 145 receives at its input:

• the signal 134b emitted by the circuit 134 for detecting the direction of movement,
• the counting signal 131b emitted by the counter 131 and
• the associated signal emitted by the processing unit 133 and corresponding to the set value of the reversal points X0,X3;
  and outputs:
• a signal 145b corresponding to the value of the error measured during travel through the reversal points;

said signal 145b is sent to the respective right-hand storage unit 143 or left-hand storage unit 144 which in turn emits a corresponding signal which is sent to the input of the associated calculation units 141,142 which, receiving at their input also a pre-set initial error signal 141a (for the sake of convenience the same on the right and on the left), performs calculation of the new value of the switching points X2,X5 for which the reversal error is minimized during the next travel stroke.

[0037] In other words, the apparatus is able to displace, with each travel stroke, the torque reversal points X2,X5 depending on the error in the reversal point detected during the previous travel stroke.

[0038] This calculated value 141b,142b is input into the position comparator 132b which in turn provides the new torque direction signal 132b.

[0039] The operating principle of the apparatus (Figs. 1, 3a,3b) is as follows:

• the processing parameters for the specific form of the reel to be produced are defined (speed of rotation of the reel, number of turns, angle of lay, angle between turns, etc.),
• the following are also established:
  • the position of the reversal points X0,X3 with respect to the absolute zero,
  • the maximum programmed speed for the thread guide 6a in relation to processing (of the thread) in progress;
  • the initial error.

[0040] This initial error is introduced specifically in order to determine two initial switching points, and hence reversal points, which are definitely located internally with respect to the two actual reversal points X0,X3, thus ensuring that the reversal error during the first rotation is definitely an underestimation error such as not to move the thread beyond the maximum dimension of the reel, with consequent breakage of said thread and blockage of the apparatus;

• the following preliminary operations, already described, are performed:
  • vectorial phase synchronization in order to determine the maximum torque condition,
  • detection of the absolute zero with initialization of the counter 131,
  • positioning of the thread guide in a position between the reversal points.

[0041] Starting the winding cycle and assuming winding in the clockwise direction, the speed control device 135 will initially request the maximum torque available in order to bring the thread guide 6a, which is at a standstill, to the programmed working speed which is maintained until the thread guide reaches the predefined, right-hand, first switching point X2 which is calibrated by means of the initial error introduced by the operator and is detected by the position comparator 132 and where the said comparator 132 causes reversal of the direction, adding 180° to the actual value of α detected and sending the corresponding signal 132b to the conversion block 122.

[0042] This reversal causes braking of the motor and hence a reduction in the speed of the thread guide which is detected by the speed control circuit which reacts by requesting greater torque in order to compensate for the slowing down effect; in this way, since the torque is directed in the opposite direction to the direction of rotation of the motor, the thread guide is brought to zero speed at the reversal point X3 where the direction of its movement is reversed, said movement thereby matching the torque which, from this point, pushes the thread guide so as to reach the programmed speed 133c for the linear return section.

[0043] The programmed speed is reached at the point X4 where the speed control circuit reduces the required torque signal, keeping it at the minimum value necessary for maintaining the speed as far as the first left-hand reversal point X5 which is calibrated by the initial error introduced by the operator and where the torque reversal cycle and then the thread guide movement reversal cycle are repeated when the reversal point X0 is reached.

[0044] When the two reversal points, i.e. the right-hand reversal point X0 and the left-hand reversal point X3, are passed through, the respective error calculation circuits 141,142 detect the underestimation of the reversal point X0,X3 and set the new value of X2,X5 which compensates for the initial error set so that, as from the second rotation, reversal of the movement occurs at the predefined reversal points less the intrinsic error of the apparatus.

[0045] In the case where greater precision is required with regard to attainment of the points for reversal of the movement of the thread guide 6a, compensating for any errors, due to external causes, between one detection operation and the next, it is envisaged that the control apparatus may also comprise a position control device 150 which intervenes, in place of the speed control circuit 135, along the section respectively lying between the right-hand switching point X2 and left-hand switching point X5 and the associated reversal point X0,X3.

[0046] In greater detail and with reference to Figs. 4,5a,5b, said position control device comprises:

• means 151 for disabling the speed control system and enabling the position control system, represented by way of example in the figures by a switch which is able to switch from a position for enabling the speed control circuit 135 to a position for enabling:
• a position control circuit 152 which receives at its input:
  • a reference signal 133f representing the programmed position for the reversal point X0,X3;
  • a signal 131b which indicates the existing position of the thread guide 6a and is sent from the counter 131;
  • an existing speed signal 135f.

[0047] In this way the circuit 152 is able to perform the following:

+ detect continuously, along the section X2-X3 or X0-X5, the difference D between the programmed value of X0,X5 and the existing value of the thread guide position;

+ compare the corresponding existing speed value with the programmed speed value for that point;

+ calculate the relevant difference δV between said speeds;

+ intervene so as to generate a signal 152b for varying the modulus of the torque which may be increased/decreased depending on the sign of the difference δV detected.

[0048] In a simplified alternative embodiment of the position control device, it is also possible to perform variation of the torque 152b in accordance with a graph which is a function of the sole variable D instead of the variable δV.

[0049] Basically the position control device causes a short slowing down transient for the thread guide which allows the correction of any imprecision accumulated during the travel thereof, which is controlled only in terms of speed, as well as attainment of the programmed reversal point with a high degree of precision.

[0050] Once the reversal point X0,X3 is reached (D=0), the control device 133 again switches the switch 151 to the speed control device 135 which, finding a zero speed, instantaneously recalls the maximum torque value so as to adjust as rapidly as possible the speed of the thread guide to the programmed travel speed and resume normal control of the thread guide.

[0051] As illustrated in Fig. 1, it is also envisaged that the apparatus may comprise a second encoder 210 which is located between the reel 1 and the calculation unit 133 and by means of which it is possible to control the speed of the thread guide according to the speed of the reel and/or another parameter external to the control apparatus, so as to produce windings of a special type. It is therefore obvious how, with the apparatus according to the invention, it is possible to reverse the direction of the torque when the speed of the thread guide is still at a maximum level, thereby achieving a reduction in the time required for reversal of the thread guide movement; moreover, with the speed control system according to the invention it is possible to limit the current supplied to the motor to the minimum value required, limiting the dissipation phenomena and therefore wear of the said motor.

Claims

1. Apparatus for controlling the alternating movement of a thread guide (6a) which is actuated by an electric motor (4) via means (5a,5b,6) supporting the said thread guide and is intended to wind a thread (7) onto rotating supports (1)
characterized in that it comprises

- an angular transducer (110) for detecting the angular position of the rotor (4a) of the motor (4);

- a device (120) for vectorial control of the currents supplied to the motor (4);

- a circuit (130) for controlling the speed of rotation of the rotor (4a), which is connected to the angular transducer (110) and to the vector control circuit (120).

2. Apparatus according to Claim 1, characterized in that said angular transducer (110) is an encoder.

3. Apparatus according to Claim 1, characterized in that said angular transducer is of the incremental type.

4. Apparatus according to Claim 1, characterized in that said device for vectorial control of the currents comprises at least one bidirectional counter (21) for counting and memorizing the pulses (110b) of the angular transducer (110).

5. Apparatus according to Claim 1, characterized in that said device for vectorial control of the currents comprises at least one vector conversion circuit formed by a conversion block (122) and by at least one pair of multipliers (123) which receive an input signal from the speed regulation circuit (135).

6. Apparatus according to Claim 1, characterized in that said device for vectorial control of the currents comprises means (124) for switching from a normal operating condition (A) to an initial phase synchronization condition (B).

7. Apparatus according to Claims 1 and 6, characterized in that, in phase synchronization conditions, said counter (121) is set to a value corresponding to a phase displacement of 90° between the vector representing the vectorial sum of the stator magnetic fields and the vector representing the magnetic field of the rotor (4a).

8. Apparatus according to Claim 1, characterized in that said speed control circuit (130) comprises at least one bidirectional counter (131) for counting and memorizing the pulses (110b) of the angular transducer (110).

9. Apparatus according to Claim 8, characterized in that said speed control circuit comprises a direction of movement detector (134) and a position comparator (132) able to generate a directional signal (132b) for the torque to be output, which is sent to the input of the vector control conversion block (122).

10. Apparatus according to Claim 8, characterized in that it comprises a speed regulation device (135) designed to emit said signal (132b) regulating the modulus of the current supplied to the motor (4).

11. Apparatus according to Claim 1, characterized in that it comprises a circuit (140) for detecting and compensating for the error in the right-hand reversal point (X0) and left-hand reversal point (X3).

12. Apparatus according to Claim 11, characterized in that said error compensation circuit comprises at least one pair of calculation units (141, 142) which are designed to calculate the subsequent torque reversal point (X2,X5) and emit corresponding signals (141b, 142b) to be sent to the comparator (132).

13. Apparatus according to Claim 12, characterized in that it comprises a right-hand and left-hand error measuring device (145) and at least one unit (143) for storing this error.

14. Apparatus according to Claim 13, characterized in that said storage devices are two in number (143, 144).

15. Apparatus according to Claim 1, characterized in that it comprises a position control circuit (150) able to modify the conditions for approaching the reversal point.

16. Apparatus according to Claim 15, characterized in that said position control circuit comprises means (151) for enabling position control and disabling speed control and vice versa and a torque regulator (152).

17. Apparatus according to Claim 16, characterized in that said torque regulator (152) receives at its input the signal (131b) of the position counter (131), a reference signal (133f) corresponding to the programmed reversal point (X0,X3) and a signal (135f) indicating the existing speed of the thread guide and emits a signal (152b) indicating the modulus of the torque to be sent to the vector control circuit.

18. Apparatus according to Claim 17, characterized in that said signal (152b) emitted by the regulator (152) is a function of the difference (D) between the programmed reversal point and the existing position.

19. Apparatus according to Claim 17, characterized in that said signal (152b) emitted by the regulator (152) is a function of the difference in speed (6V) between the programmed speed and the speed detected in the existing position (D).

20. Apparatus according to Claim 1, characterized in that it comprises a second angular transducer (120) located between the reel (1) and the calculation unit (133).

21. Apparatus according to Claim 1, characterized in that said motor (4) is a multiple-pole motor.

22. Apparatus according to Claim 21, characterized in that said motor is a stepper motor.

23. Method for controlling the alternating movement of a thread guide (6a) which is actuated by an electric motor (4) via means (5a,5b,6) supporting the said thread guide and is intended to wind a thread (7) onto rotating supports, characterised in that it comprises the steps of:

- detecting the angular position of the rotor (4a) of the motor (4) via associated means (110);

- sending corresponding signals to a circuit (120) controlling the currents supplied to the motor (4) and to a circuit (130) controlling the speed of the thread guide;

- vectorial control of the currents supplied to the motor;

- control of the speed of the thread guide (6a).

24. Method according to Claim 23, characterized in that said detection of the angular position of the rotor (4a) of the motor (4) is performed by means of an angular transducer (110).

25. Method according to Claim 24, characterized in that said transducer (110) is incremental.

26. Method according to Claim 23, characterized in that it envisages the following steps:

- counting and memorizing the signals relating to the angular position of the rotor;

- generating corresponding counting signals;

- vectorial conversion of said counting signals;

- multiplication of said converted signals by a torque value determined by the speed control device;

- power amplification of the current values obtained by means of said multiplication;

- sending of the amplified signals to the motor.

27. Method according to Claim 23, characterized in that it comprises an initial phase synchronization step for relative orientation of the vector representing the vectorial sum of the stator magnetic fields and the magnetic field of the rotor of the motor.

28. Method according to Claim 27, characterized in that said relative orientation envisages 90° phase displacement of said vectors.

29. Method according to Claim 28, characterized in that said phase displacement is maintained for each point along the angular trajectory of the rotor.

30. Method according to Claim 27, characterized in that said initial phase synchronization envisages the following steps:

- supplying, to the stator phases, currents such as to produce a stator field oriented at a predefined angle;

- waiting for a predefined time interval;

- setting the count to a number corresponding to a predefined angle of the stator field;

- incrementing this number by a value corresponding to a phase displacement of 90°.

31. Method according to Claim 23, characterized in that said control of the speed of the thread guide comprises the steps of:

- counting and memorizing the pulses representing the position of the thread guide;

- determining the direction of movement of the thread guide;

- comparing the count value of the existing position of the thread guide and the programmed value;

- sending torque directional signals to the device for vectorial control of the currents;

- generating a signal indicating the modulus of the torque required for the existing trajectory section;

- sending said signal indicating the modulus of the torque to the circuit for vectorial control of the currents.

32. Method according to Claim 31, characterized in that said speed control envisages an initial zero search step.

33. Method according to Claim 32, characterized in that said zero search operation envisages the following steps:

- reduction of the torque and the speed of the motor to a predefined value;

- displacement of the thread guide into a position corresponding to the absolute zero of the machine;

- resetting of the thread-guide position count;

- displacement of the thread guide into the cycle start position;

- resetting of the motor current and torque.

34. Method according to Claim 23, characterized in that it comprises error correction of the reversal point of the thread guide movement.

35. Method according to Claim 34, characterized in that said error correction envisages the following steps:

- detection and measurement of the error in the existing right-hand and left-hand speed reversal point;

- separate storage of said right-hand and left-hand error;

- calculation of the respective subsequent torque reversal point;

- sending of the calculated reversal point to the system for comparing the existing value and the programmed value.

36. Method according to Claim 35, characterized in that said calculation of the new torque reversal point is performed on the basis of the programmed value and the error detected and stored during the previous travel movement.

37. Method according to Claim 23, characterized in that it comprises positional control along the section lying between the torque reversal point and the movement reversal point.

38. Method according to Claim 37, characterized in that said positional control envisages the following steps:

- detecting the torque reversal point;

- deactivating the speed control;

- activating the positional control;

- detecting the programmed position for the speed reversal point;

- detecting the existing position;

- calculating the difference between the two positions, i.e. the programmed position and the existing position;

- determining the torque value to be output.

39. Method according to Claim 38, characterized in that said determination of the torque value to be output is a function of the said difference between the two positions.

40. Method according to Claim 38, characterized in that said determination of the torque value to be output is a function of the calculated difference between the programmed speed and existing speed at the position of the said difference between the two positions.

Ansprüche

1. Vorrichtung zum Steuern der alternierenden Bewegung eines Fadenführers (6a), der mit einem Elektromotor (4) über den Fadenführer abstützende Mittel (5a, 5b, 6) betätigt wird und einen Faden (7) auf umlaufende Träger (1) aufwickeln soll,
dadurch gekennzeichnet, dass sie

- einen Winkelgeber (110) zum Feststellen der Winkellage des Läufers (4a) des Motors (4);

- eine Anordnung (120) zur Vektorsteuerung der dem Motor (4) zugeführten Ströme und

- einen Schaltkreis (130) zum Regeln der Drehzahl des Läufers (4a), der mit dem Winkelgeber (110) und dem Vektorsteuerkreis (120) verbunden ist,

aufweist.

2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass der Winkelgeber (110) ein Codierer ist.

3. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass der Winkelgeber ein inkrementeller Geber ist.

4. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass die Anordnung zur Vektorsteuerung der Ströme mindestens einen bidirektionalen Zähler (21) zum Zählen und Speichern der Impulse (110b) des Winkelgebers (110) aufweist.

5. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass die Anordnung zur Vektorsteuerung der Ströme mindestens einen Vektorumwandlungsschaltkreis aufweist, der aus einem Umwandlungsblock (122) und mindestens einem Paar Multiplizierer (123), die ein Eingangssignal von einem Drehzahlregelungsschaltkreis (135) empfangen, besteht.

6. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass die Anordnung zur Vektorsteuerung der Ströme Mittel (124) zum Umschalten von einem normalen Betriebszustand (A) zu einem Anfangsphasensynchronisationszustand (B) aufweist.

7. Vorrichtung nach den Ansprüchen 1 und 6, dadurch gekennzeichnet, dass bei vorliegender Phasensynchronisation der Zähler (121) auf einen Wert gesetzt wird, der einer Phasenverschiebung von 90° zwischen dem Vektor, der die Vektorsumme der Magnetfelder des Ständers verkörpert, und dem Vektor des Magnetfelds des Läufers (4a) entspricht.

8. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass der Drehzahlregelungsschaltkreis (130) mindestens einen bidirektionalen Zähler (131) zum Zählen und Speichern der Impulse (110b) des Winkelgebers (110) aufweist.

9. Vorrichtung nach Anspruch 8, dadurch gekennzeichnet, dass der Drehzahlregelungsschaltkreis einen Bewegungsrichtungsdetektor (134) und einen Lagekomparator (132) aufweist, der ein Richtungssignal (132b) für das auszugebende Drehmoment erzeugen kann, das an den Eingang des Vektorsteuerungs-Umwandlungsblocks (122) gesendet wird.

10. Vorrichtung nach Anspruch 8, dadurch gekennzeichnet, dass sie einen Drehzahlregler (135) aufweist, der so ausgelegt ist, dass er das Signal (132b) ausgibt, das den Modul des dem Motor (4) zugeführten Stroms regelt.

11. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass sie einen Schaltkreis (140) zum Feststellen und Kompensieren des Fehlers am rechten Umkehrpunkt (X0) und am linken Umkehrpunkt (X3) aufweist.

12. Vorrichtung nach Anspruch 11, dadurch gekennzeichnet, dass der Fehlerkompensationsschaltkreis mindestens ein Paar Rechenwerke (141, 142) aufweist, die so ausgelegt sind, dass sie die nachfolgenden Drehmoment-Umkehrpunkte (X2, X5) berechnen und entsprechende Signale (141b, 142b) ausgeben, die an den Komparator (132) gesendet werden sollen.

13. Vorrichtung nach Anspruch 12, dadurch gekennzeichnet, dass sie eine Anordnung zum Messen des rechten und linken Fehlers (145) und mindestens eine Einheit zum Speichern dieses Fehlers (143) aufweist.

14. Vorrichtung nach Anspruch 13, dadurch gekennzeichnet, dass die Anzahl der Speicheranordnungen zwei ist (143, 144).

15. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass sie einen Lageregelkreis (150) aufweist, der die Bedingungen für die Annäherung an den Umkehrpunkt modifizieren kann.

16. Vorrichtung nach Anspruch 15, dadurch gekennzeichnet, dass der Lageregelkreis Mittel (151) zum Aktivieren der Lageregelung und zum Deaktivieren der Drehzahlregelung und umgekehrt und einen Drehmomentregler (152) aufweist.

17. Vorrichtung nach Anspruch 16, dadurch gekennzeichnet, dass der Drehmomentregler (152) an seinem Eingang das Signal (131b) des Lagezählers (131), ein Bezugssignal (133f), das dem programmierten Umkehrpunkt (X0, X3) entspricht, und ein Signal (135f), das die aktuelle Drehzahl des Fadenführers angibt, empfängt und ein den Modul des Drehmoments angebendes Signal (152b) ausgibt, das an den Vektorsteuerkreis gesendet werden soll.

18. Vorrichtung nach Anspruch 17, dadurch gekennzeichnet, dass das Signal (152b), das von dem Regler (152) ausgegeben wird, eine Funktion der Differenz (D) zwischen dem programmierten Umkehrpunkt und der aktuellen Position ist.

19. Vorrichtung nach Anspruch 17, dadurch gekennzeichnet, dass das Signal (152b), das von dem Regler (152) ausgegeben wird, eine Funktion der Drehzahldifferenz (δV) zwischen der programmierten Drehzahl und der an der aktuellen Position festgestellten Drehzahl ist.

20. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass sie einen zweiten Winkelgeber (120) aufweist, der zwischen der Haspel (1) und dem Rechenwerk (133) angeordnet ist.

21. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass der Motor (4) ein mehrpoliger Motor ist.

22. Vorrichtung nach Anspruch 21, dadurch gekennzeichnet, dass der Motor ein Schrittmotor ist.

23. Verfahren zum Steuern der alternierenden Bewegung eines Fadenführers (6a), der mit einem Elektromotor (4) über den Fadenführer abstützende Mittel (5a, 5b, 6) betätigt wird und einen Faden (7) auf umlaufende Träger (1) aufwickeln soll,
dadurch gekennzeichnet, dass es die Schritte

- Feststellen der Winkellage des Läufers (4a) des Motors (4) über zugehörige Mittel (110);

- Senden entsprechender Signale an einen Schaltkreis (120), der die dem Motor (4) zugeführten Ströme regelt, und an einen Schaltkreis (130), der die Drehzahl des Fadenführers regelt;

- Vektorsteuerung der dem Motor zugeführten Ströme und

- Regelung der Drehzahl des Fadenführers (6a)

aufweist.

24. Verfahren nach Anspruch 23, dadurch gekennzeichnet, dass das Feststellen der Winkellage des Läufers (4a) des Motors (4) mit einem Winkelgeber (110) durchgeführt wird.

25. Verfahren nach Anspruch 24, dadurch gekennzeichnet, dass der Geber (110) ein inkrementeller Geber ist.

26. Verfahren nach Anspruch 23, dadurch gekennzeichnet, dass es die Schritte

- Zählen und Speichern der die Winkellage des Läufers betreffenden Signale;

- Erzeugen entsprechender Zählsignale;

- Vektorumwandlung der Zählsignale;

- Multiplizieren der umgewandelten Signale mit einem von dem Drehmomentwertregler bestimmten Wert;

- Leistungsverstärkung der durch die Multiplikation erhaltenen Stromwerte und

- Senden der verstärkten Signale an den Motor

vorsieht.

27. Verfahren nach Anspruch 23, dadurch gekennzeichnet, dass es einen Anfangsphasensynchronisationsschritt zur relativen Orientierung des Vektors, der die Vektorsumme der Magnetfelder des Ständers verkörpert, und des Vektors des Magnetfelds des Motorläufers aufweist.

28. Verfahren nach Anspruch 27, dadurch gekennzeichnet, dass die relative Orientierung eine 90°-Phasenverschiebung der Vektoren vorsieht.

29. Verfahren nach Anspruch 28, dadurch gekennzeichnet, dass die Phasenverschiebung für jeden Punkt entlang der Winkeltrajektorie des Läufers aufrechterhalten wird.

30. Verfahren nach Anspruch 27, dadurch gekennzeichnet, dass die Anfangsphasensynchronisation die Schritte

- Zuführen von Strömen zu den Ständerphasen, sodass ein Ständerfeld entsteht, das in einem vorgegebenen Winkel orientiert ist;

- eine bestimmte Zeit lang Warten;

- Setzen des Zählers auf eine Zahl, die einem vorgegebenen Winkel des Ständerfelds entspricht; und

- Erhöhen dieser Zahl um einen Wert, der einer Phasenverschiebung von 90° entspricht, vorsieht.

31. Verfahren nach Anspruch 23, dadurch gekennzeichnet, dass das Regeln der Drehzahl des Fadenführers die Schritte

- Zählen und Speichern der Impulse, die die Lage des Fadenführers verkörpern;

- Bestimmen der Bewegungsrichtung des Fadenführers;

- Vergleichen des Zählwerts der aktuellen Position des Fadenführers mit dem programmierten Wert;

- Senden von Drehmomentrichtungssignalen an die Anordnung zur Vektorsteuerung der Ströme;

- Erzeugen eines Signals, das den Modul des Drehmoments angibt, das für den aktuellen Trajektorie-Abschnitt erforderlich ist; und

- Senden des den Modul des Drehmoments angebenden Signals an den Schaltkreis zur Vektorsteuerung der Ströme

aufweist.

32. Verfahren nach Anspruch 31, dadurch gekennzeichnet, dass die Drehzahlregelung einen Anfangsnullsuchschritt vorsieht.

33. Verfahren nach Anspruch 32, dadurch gekennzeichnet, dass die Nullsuche die Schritte

- Reduzieren des Drehmoments und der Drehzahl des Motors auf einen vorgegebenen Wert;

- Verschieben des Fadenführers zu einer Position, die dem absoluten Nullpunkt der Maschine entspricht;

- Rücksetzen des Fadenführerpositionszählers;

- Verschieben des Fadenführers zu einer Taktausgangsposition und

- Rücksetzen des Motorstroms und -drehmoments

vorsieht.

34. Verfahren nach Anspruch 23, dadurch gekennzeichnet, dass es eine Fehlerkorrektur des Umkehrpunkts der Fadenführerbewegung aufweist.

35. Verfahren nach Anspruch 34, dadurch gekennzeichnet, dass die Fehlerkorrektur die Schritte

- Feststellen und Messen des Fehlers am aktuellen rechten und linken Drehzahl-Umkehrpunkt;

- getrenntes Speichern des rechten und linken Fehlers;

- Berechnen des jeweiligen nachfolgenden Drehmoment-Umkehrpunkts undSenden des berechneten Umkehrpunkts an das System zum Vergleichen des aktuellen Werts mit dem programmierten Wert

vorsieht.

36. Verfahren nach Anspruch 35, dadurch gekennzeichnet, dass das Berechnen des neuen Drehmoment-Umkehrpunkts aufgrund des programmierten Werts und des Fehlers erfolgt, der bei der vorangehenden Bewegung festgestellt und gespeichert worden ist.

37. Verfahren nach Anspruch 23, dadurch gekennzeichnet, dass es eine Lageregelung entlang dem Abschnitt aufweist, der zwischen dem Drehmoment-Umkehrpunkt und dem Bewegungs-Umkehrpunkt liegt.

38. Verfahren nach Anspruch 37, dadurch gekennzeichnet, dass die Lageregelung die Schritte

- Feststellen des Drehmoment-Umkehrpunkts;

- Deaktivieren der Drehzahlregelung;

- Aktivieren der Lageregelung;

- Feststellen der programmierten Position für den Drehzahl-Umkehrpunkt;

- Feststellen der aktuellen Position;

- Berechnen der Differenz zwischen den beiden Positionen, d. h. der programmierten Position und der aktuellen Position; und

- Bestimmen des auszugebenden Drehmomentwerts

vorsieht.

39. Verfahren nach Anspruch 38, dadurch gekennzeichnet, dass das Bestimmen des auszugebenden Drehmomentwerts eine Funktion der Differenz zwischen den beiden Positionen ist.

40. Verfahren nach Anspruch 38, dadurch gekennzeichnet, dass das Bestimmen des auszugebenden Drehmomentwerts eine Funktion der berechneten Differenz zwischen der programmierten Drehzahl und der aktuellen Drehzahl an der Position der Differenz zwischen den beiden Positionen ist.

Revendications

1. Dispositif de commande du mouvement alternatif d'un guide-fil (6a) qui est actionné par un moteur électrique (4) par l'intermédiaire de moyens (5a, 5b, 6) supportant ledit guide-fil et est destiné à enrouler un fil (7) sur des supports rotatifs (1)
caractérisé en ce qu'il comprend

- un transducteur angulaire (110) pour détecter la position angulaire du rotor (4a) du moteur (4),

- un dispositif (120) pour la commande vectorielle des courants appliqués au moteur (4),

- un circuit (130) pour commander la vitesse de rotation du rotor (4a), qui est connecté au transducteur angulaire (110) et au circuit de commande vectorielle (120).

2. Dispositif selon la revendication 1, caractérisé en ce que ledit transducteur angulaire (110) est un codeur.

3. Dispositif selon la revendication 1, caractérisé en ce que ledit transducteur angulaire est du type incrémentiel.

4. Dispositif selon la revendication 1, caractérisé en ce que ledit dispositif de commande vectorielle des courants comprend au moins un compteur bidirectionnel (21) pour compter et mémoriser les impulsions (110b) du transducteur angulaire (110).

5. Dispositif selon la revendication 1, caractérisé en ce que ledit dispositif de commande vectorielle des courants comprend au moins un circuit de conversion vectorielle formé par un bloc de conversion (122) et par au moins une paire de multiplicateurs (123) qui reçoivent un signal d'entrée du circuit de régulation de la vitesse (135).

6. Dispositif selon la revendication 1, caractérisé en ce que ledit dispositif de commande vectorielle des courants comprend des moyens (124) pour passer d'une condition de fonctionnement normal (A) à une condition de synchronisation de phase initiale (B).

7. Dispositif selon les revendications 1 à 6, caractérisé en ce que dans des conditions de synchronisation de phase, ledit compteur (121) est réglé sur une valeur correspondant à un déphasage de 90° entre le vecteur représentant la somme vectorielle des champs magnétiques du stator et le vecteur représentant le champ magnétique du rotor (4a).

8. Dispositif selon la revendication 1, caractérisé en ce que ledit circuit de commande de la vitesse (130) comprend au moins un compteur bidirectionnel (131) pour compter et mémoriser les impulsions (110b) du transducteur angulaire (110).

9. Dispositif selon la revendication 8, caractérisé en ce que ledit circuit de commande de la vitesse comprend un détecteur de sens du mouvement (134) et un comparateur de position (132) capable de générer un signal directionnel (132b) pour le couple à produire, qui est envoyé à l'entrée du bloc de conversion (122) de commande vectorielle.

10. Dispositif selon la revendication 8, caractérisé en ce qu'il comprend un dispositif de régulation de la vitesse (135) destiné à émettre ledit signal (132b) régulant le module du courant fourni au moteur (4).

11. Dispositif selon la revendication 1, caractérisé en ce qu'il comprend un circuit (140) pour détecter et compenser l'erreur dans le point de renversement à droite (X0) et le point de renversement à gauche (X3).

12. Dispositif selon la revendication 11, caractérisé en ce que ledit circuit de compensation d'erreur comprend au moins une paire d'unités de calcul (141, 142) qui sont destinées à calculer le point de renversement du couple subséquent (X2, X5) et à émettre les signaux correspondants (141b, 142b) à envoyer au comparateur (132).

13. Dispositif selon la revendication 12, caractérisé en ce qu'il comprend un dispositif de mesure (145) de l'erreur à droite et à gauche et au moins une unité (143) pour stocker cette erreur.

14. Dispositif selon la revendication 13, caractérisé en ce que lesdits dispositifs de stockage sont au nombre de deux (143, 144).

15. Dispositif selon la revendication 1, caractérisé en ce qu'il comprend un circuit de commande de position (150) capable de modifier les conditions pour approcher du point de renversement.

16. Dispositif selon la revendication 15, caractérisé en ce que ledit circuit de commande de position comprend des moyens (151) pour valider la commande de position et invalider la commande de vitesse et vise-versa et un régulateur de couple (152).

17. Dispositif selon la revendication 16, caractérisé en ce que ledit régulateur de couple (152) reçoit à son entrée le signal (131b) du compteur de position (131), un signal de référence (133f) correspondant au point de renversement programmé (X0, X3) et un signal (135f) indiquant la vitesse existante du guide-fil et émet un signal (152b) indiquant le module du couple à envoyer au circuit de commande vectorielle.

18. Dispositif selon la revendication 17, caractérisé en ce que ledit signal (152b) émis par le régulateur (152) est une fonction de la différence (D) entre le point de renversement programmé et la position existante.

19. Dispositif selon la revendication 17, caractérisé en ce que ledit signal (152b) émis par le régulateur (152) est une fonction de la différence de vitesse (δV) entre la vitesse programmée et la vitesse détectée dans la position existante (D).

20. Dispositif selon la revendication 1, caractérisé en ce qu'il comprend un deuxième transducteur angulaire (120) situé entre la bobine (1) et l'unité de calcul (133).

21. Dispositif selon la revendication 1, caractérisé en ce que ledit moteur (4) est un moteur multipolaire.

22. Dispositif selon la revendication 21, caractérisé en ce que ledit moteur est un moteur pas à pas.

23. Procédé pour commander le mouvement alternatif d'un guide-fil (6a) qui est actionné par un moteur électrique (4) par l'intermédiaire de moyens (5a, 5b, 6) supportant ledit guide-fil et est destiné à enrouler un fil (7) sur des supports rotatifs, caractérisé en ce qu'il comprend les étapes consistant :

- à détecter la position angulaire du rotor (4a) du moteur (4) par l'intermédiaire de moyens associés (110),

- à envoyer des signaux correspondants à un circuit (120) commandant les courants fournis au moteur (4) et à un circuit (130) commandant la vitesse du guide-fil,

- en la commande vectorielle des courants fournis au moteur,

- en la commande de la vitesse du guide-fil (6a).

24. Procédé selon la revendication 23, caractérisé en ce que ladite détection de la position angulaire du rotor (4a) du moteur (4) est effectuée au moyen d'un transducteur angulaire (110).

25. Procédé selon la revendication 24, caractérisé en ce que ledit transducteur (110) est incrémentiel.

26. Procédé selon la revendication 23, caractérisé en ce qu'il envisage les étapes suivantes :

- comptage et mémorisation des signaux en rapport avec la position angulaire du rotor,

- génération des signaux de comptage correspondants,

- conversion vectorielle desdits signaux de comptage,

- multiplication desdits signaux convertis par une valeur de couple déterminée par le dispositif de commande de la vitesse,

- amplification en puissance des valeurs de courant obtenues au moyen de ladite multiplication,

- envoi des signaux amplifiés au moteur.

27. Procédé selon la revendication 23, caractérisé en ce qu'il comprend une étape de synchronisation de phase initiale pour l'orientation relative du vecteur représentant la somme vectorielle des champs magnétiques du stator et du champ magnétique du rotor du moteur.

28. Procédé selon la revendication 27, caractérisé en ce que ladite orientation relative envisage le déphasage de 90° desdits vecteurs.

29. Procédé selon la revendication 28, caractérisé en ce que ledit déphasage est maintenu pour chaque point le long de la trajectoire angulaire du rotor.

30. Procédé selon la revendication 27, caractérisé en ce que ladite synchronisation de phase initiale envisage les étapes suivantes :

- fournir aux phases du stator des courants de manière à produire un champ de stator orienté à un angle prédéfini,

- attendre pendant un intervalle de temps prédéfini,

- régler le comptage sur un nombre correspondant à un angle prédéfini du champ du stator,

- incrémenter ce nombre d'une valeur correspondant au déphasage de 90°.

31. Procédé selon la revendication 23, caractérisé en ce que ladite commande de la vitesse du guide-fil comprend les étapes consistant à :

- compter et mémoriser les impulsions représentant la position du guide-fil,

- déterminer le sens de mouvement du guide-fil,

- comparer la valeur de comptage de la position existante du guide-fil et la valeur programmée,

- envoyer des signaux directionnels de couple au dispositif pour la commande vectorielle des courants,

- générer un signal indiquant le module du couple requis pour la section de trajectoire existante,

- envoyer ledit signal indiquant le module du couple au circuit de commande vectorielle des courants.

32. Procédé selon la revendication 31, caractérisé en ce que ladite commande de la vitesse envisage une étape de recherche zéro initiale.

33. Procédé selon la revendication 32, caractérisé en ce que ladite opération de recherche zéro envisage les étapes suivantes :

- réduction du couple et de la vitesse du moteur à une valeur prédéfinie,

- déplacement du guide-fil dans une position correspondant au zéro absolu de la machine,

- remise à zéro du comptage de position du guide-fil,

- déplacement du guide-fil dans la position de début de cycle,

- remise à zéro du courant du moteur et du couple.

34. Procédé selon la revendication 23, caractérisé en ce qu'il comprend la correction d'erreur du point de renversement du mouvement du guide-fil.

35. Procédé selon la revendication 34, caractérisé en ce que ladite correction d'erreur envisage les étapes suivantes :

- détection et mesure de l'erreur au point de renversement existant de la vitesse à droite et à gauche,

- stockage séparé de ladite erreur à droite et à gauche,

- calcul de chaque point de renversement du couple subséquent,

- envoi du point de renversement calculé au système pour comparer la valeur existante et la valeur programmée.

36. Procédé selon la revendication 35, caractérisé en ce que ledit calcul du nouveau point de renversement du couple est effectué sur la base de la valeur programmée et de l'erreur détectée et stockée pendant le mouvement de translation précédent.

37. Procédé selon la revendication 23, caractérisé en ce qu'il comprend la commande positionnelle le long de la section se trouvant entre le point de renversement du couple et le point de renversement du mouvement.

38. Procédé selon la revendication 37, caractérisé en ce que la commande positionnelle envisage les étapes suivantes :

- détecter le point de renversement du couple,

- désactiver la commande de la vitesse,

- activer la commande de position,

- détecter la position programmée pour le point de renversement de la vitesse,

- détecter la position existante,

- calculer la différence entre les deux positions, c'est-à-dire la position programmée et la position existante,

- déterminer la valeur du couple à produire.

39. Procédé selon la revendication 38, caractérisé en ce que ladite détermination de la valeur du couple à produire est une fonction de ladite différence entre les deux positions.

40. Procédé selon la revendication 38, caractérisé en ce que ladite détermination de la valeur du couple à produire est une fonction de la différence calculée entre la vitesse programmée et la vitesse existante au niveau de la position de ladite différence entre les deux positions.

Drawing