JP2006304511A - Drive control unit of stepping motor, and sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve precision in the amount of the drive of a drive system significantly by canceling an error by the hysteresis of the amount of drive in a system to be driven when performing drive control to the system driven by a stepping motor. <P>SOLUTION: In the drive control for performing feedback control to an X-directional drive motor by an encoder signal, there are a counter for counting the number of drive pulses to the X-directional drive motor, and a signal counter for counting the number of encode signals. A home position setting operation is executed in a cloth feeding device driven by the X-directional drive motor (S12). When the counted value of the number of commands when the home position setting operation is completed does not coincide with a signal count value × C (C is a prescribed positive constant) (S13:No), a specified hysteresis cancellation operation of the cloth feeding device is executed by the X-directional drive motor (S14) for canceling the hysteresis in the cloth feeding device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stepping motor drive control device and a sewing machine, and more particularly to a drive control device that eliminates hysteresis with respect to a command value for controlling a stepping motor when a driven system is driven and controlled by a stepping motor.

  Conventionally, when driving various drive systems, stepping motors that are easy to drive control by an open loop are mostly used. For example, in an electronic sewing machine, a small and easy-to-control stepping motor is used when a needle bar is swung by a needle swing mechanism or a cloth is fed by a cloth feed drive mechanism via a feed dog.

  By the way, when carrying out the cloth feed operation by moving the feed dog or the cloth holding frame, if the load is large, there is an error between the number of command pulses from the control means and the number of encoder signals for the rotation amount of the pulse motor. Occurs, and the feed dog and the cloth holding frame cannot be moved accurately, causing a problem of pattern collapse. Therefore, various stepping motor control techniques have been proposed in which the output of the pulse motor is always set to the maximum torque and the predetermined driving amount is always secured to prevent the occurrence of pattern collapse.

  For example, the pulse motor control program described in Patent Document 1 sets an ideal deviation value in each drive section such as when the pulse motor is accelerating or during the first stage of deceleration, and drives at any time during the drive control. An actual deviation value, which is the difference between the first pulse number commanded to be performed and the second pulse number that is the number of encoder signals, is obtained by calculation, and the next drive pulse is determined based on the set deviation value and the actual deviation value. The output timing is adjusted. That is, by adopting so-called feedback control using an encoder signal, the maximum torque can be generated when the embroidery frame is driven by a pulse motor.

  In addition, the electronic cycle sewing machine described in Patent Document 2 is provided with an X-axis and Y-axis origin sensor, origin search control means, etc., and moves the table in the X-axis direction and the Y-axis direction orthogonal to each other. The origin of the table is set when the sensor signal is input from the origin sensor of the axis and the Y axis.

  Therefore, in the pulse motor control program described in Patent Document 1, since the embroidery frame is driven by the pulse motor when the power is turned on or at the start of sewing, as in Patent Document 2, the origin setting of the embroidery frame must be executed. It is.

In Patent Document 1, when setting the origin of the embroidery frame, a first counter that counts the number of first pulses and a second counter that counts the number of second pulses are provided. Clear processing for clearing the count value of the two counter is executed, and after the origin setting processing, the count values of the first and second counters are cleared again.
JP 2004-321771 (pages 10 to 14, FIGS. 6 and 7) Japanese Patent Laid-Open No. 6-126049 (pages 3 to 5, FIG. 1)

  In Patent Document 1, when the origin setting process is executed, when driving the embroidery frame for the origin setting process and the driving load of the embroidery frame driving system is relatively large compared to the driving torque of the stepping motor, At the end of the origin setting process, the drive shaft connected to the drive shaft of the stepping motor and attached with an encoder disk that generates an encoder signal is affected by the load during driving and corresponds to the command pulse from the control means. There is a delay (so-called hysteresis) in the rotational phase with respect to the normal stop position.

  That is, in such a hysteresis state, the second count value is often smaller than the first count value. However, in this way, when the first count value and the second count value do not match, that is, in a state where hysteresis has occurred, the first and second count values are cleared again and the sewing process is executed. Therefore, even if the output timing of the drive pulse is adjusted based on the deviation value in the sewing process, there is a problem that it cannot be sufficiently reflected in the generation of the maximum torque by the pulse motor and the pattern collapse cannot be prevented reliably.

  The stepping motor drive control device according to claim 1 is a stepping motor drive control device that feedback-controls the stepping motor by an encoder signal. The stepping motor drive control device counts a command number counter that counts the number of drive pulses for the stepping motor and an encoder signal number. When the signal counter and the command count value at the end of the predetermined operation of the driven system driven by the stepping motor do not match the signal count value × C (where C is a predetermined positive constant), the stepping motor And a hysteresis elimination control means for eliminating the hysteresis of the driven system by driving the driven system in a specific operation mode.

  When the predetermined operation of the drive system is completed by driving the stepping motor, the count value of the command number counter that counts the number of drive pulses does not match the count value × C of the signal counter that counts the number of encoder signals. When a so-called hysteresis state occurs, the driven system is driven in a specific operation mode by driving the stepping motor, so the hysteresis state is eliminated and the command count value and the signal count value × C match. It becomes like this. That is, after that, the drive system is driven with the maximum torque by the stepping motor.

  According to a second aspect of the present invention, there is provided the stepping motor drive control device according to the first aspect, wherein the hysteresis elimination control means uses the stepping motor to move the driven system in the direction opposite to the operation direction of the predetermined operation and in the opposite direction by a predetermined number of pulses. By repeating the drive, the hysteresis of the driven system is eliminated.

  According to a third aspect of the present invention, there is provided the stepping motor drive control apparatus according to the second aspect, wherein the driven system includes an X-axis drive system and a Y-axis drive system that drive the drive target in the X and Y directions perpendicular to each other in a horizontal plane. The hysteresis elimination control means simultaneously eliminates hysteresis for the X-axis drive system and the Y-axis drive system.

  In a drive controller for a stepping motor according to a fourth aspect, in any one of the first to third aspects, the predetermined operation is an origin setting operation for setting an origin of a driven system driven by the stepping motor.

  According to a fifth aspect of the present invention, there is provided a driving control device for a stepping motor according to the fourth aspect, further comprising an origin setting control means for performing the origin setting operation, wherein the origin setting control means switches off a detection signal of an origin sensor provided in a driven system. The origin setting control is terminated when it is changed.

  A sewing machine according to a sixth aspect includes the stepping motor drive control device according to any one of the first to fifth aspects, and the driven system is configured by a work cloth feeding mechanism.

  According to the first aspect of the present invention, the stepping motor drive control apparatus that feedback-controls the stepping motor by the encoder signal includes the command number counter, the signal counter, and the hysteresis elimination control means. Even when a so-called hysteresis state occurs in which the command count value does not match the signal count value x C when the predetermined operation of the drive system ends, the hysteresis on the stepping motor side is reliably eliminated by the hysteresis elimination means. Therefore, the drive system can be driven with the maximum torque of the stepping motor after the end of the predetermined operation, and the accuracy of the drive amount in the drive system with respect to the drive command can be significantly increased.

  According to a second aspect of the present invention, the hysteresis elimination control means repeats driving the driven system by a stepping motor in the direction opposite to the operation direction of the predetermined operation and the opposite direction in order by a predetermined number of pulses. Eliminate drive system hysteresis. In this case, even if hysteresis is generated in the driven system due to a predetermined operation, the stepping motor is driven by a predetermined number of pulses in the direction opposite to the operation direction of the predetermined operation to execute a so-called hysteresis elimination operation. By doing so, the hysteresis of the drive system may be eliminated.

  However, even when the hysteresis of the drive system cannot be eliminated by the current hysteresis elimination operation, the hysteresis of the drive system can be reliably eliminated by repeatedly executing the hysteresis elimination operation. Other effects similar to those of the first aspect are obtained.

  According to a third aspect of the present invention, the driven system has an X-axis drive system and a Y-axis drive system that drive the drive target in the X and Y directions orthogonal to each other in a horizontal plane, The hysteresis is eliminated simultaneously for the axis drive system and the Y-axis drive system. In this case, since the cancellation of the hysteresis generated in the X-axis drive system that drives the drive target and the cancellation of the hysteresis generated in the Y-axis drive system are performed at the same time, it is possible to eliminate the hysteresis in a plurality of drive systems in a short time. Can be done quickly. Other effects similar to those of claim 2 are obtained.

  According to the invention of claim 4, the predetermined operation is an origin setting operation for setting an origin of a driven system driven by a stepping motor. In this case, the hysteresis of the drive system can be reliably eliminated in the origin setting operation executed when the power is turned on. Other effects similar to those of any one of claims 1 to 3 are provided.

  According to the invention of claim 5, the origin setting control means for performing the origin setting operation is provided, and the origin setting control means ends the origin setting control when the detection signal of the origin sensor provided in the driven system is switched. To do. In this case, the origin position can be set to the position where the origin sensor is provided using the origin sensor. Other effects similar to those of the fourth aspect are achieved.

  According to the sixth aspect of the present invention, the stepping motor drive control device according to any one of the first to fifth aspects is provided, and the driven system is the work cloth feed mechanism, so the work cloth feed mechanism is driven by the stepping motor. When controlling, the sewing machine which can exhibit the effect acquired with the drive control device of the stepping motor according to any one of claims 1 to 5 can be realized.

  The stepping motor drive control device of this embodiment is configured to drive the cloth stitching device of the pattern sewing machine with the X-direction and Y-direction drive motors composed of stepping motors. Is reciprocated by a predetermined number of steps to eliminate the hysteresis of the cloth feeding device.

  As shown in FIG. 1, the pattern stitching sewing machine 1 includes a bed portion 2, a pedestal column portion 3 erected from the rear end portion of the bed portion 2, and the bed portion 2 from the upper end portion of the pedestal column portion 3. The arm portion 4 and the like extend forward.

  Although not shown in the drawings, the pedestal 3 and the arm 4 have a sewing machine motor 7 for driving the sewing needle up and down via the needle bar 6 and the driving force of the sewing machine motor 7 via the main shaft. However, since it is a known technique, a detailed description thereof is omitted here. In addition, a needle bar vertical movement mechanism for moving the needle bar 6 up and down is provided inside the head 5 which is the front end of the arm part 4.

  Although not shown in the figure, the bed portion 2 includes a cloth holding mechanism and a cloth feeding device that moves the cloth holding mechanism in the X direction (left-right direction) and the Y direction (front-back direction), as well as the vertical movement and adjustment of the sewing needle. A rotary hook that occasionally forms pattern stitches, a lower shaft that transmits the rotational driving force of the sewing machine motor 7 to the rotary hook via the main shaft, and a thread trimming mechanism that simultaneously cuts the upper and lower threads when sewing is completed Is provided.

  Here, the cloth holding mechanism is connected to an X-direction moving body of a cloth feeding device, which will be described later, and holds a work cloth between a rectangular frame-shaped cloth holding frame 10 and a lower cloth receiving plate 11 in a plan view. Since it is well known and is not related to the present invention, its detailed description is omitted.

  A cloth feeding device that feeds a cloth by moving a cloth holding body 12 (which corresponds to a driving target) composed of a cloth holding frame 10 and a cloth receiving plate 11 in the X direction and the Y direction is simplified without illustration. explain. In the bed portion 2, a Y-direction moving mechanism that moves the Y-direction moving body in the Y direction, an X-direction moving mechanism that moves the X-direction moving body in the X direction, and the like are provided. However, the X-direction moving mechanism is driven by the Y-direction moving body of the Y-direction moving body, and the cloth holding frame 10 and the cloth receiving plate 11 are moved and driven simultaneously by the X-direction moving body.

  Here, the X-direction moving mechanism corresponds to the X-axis driving system, and the Y-direction moving mechanism corresponds to the Y-axis driving system. In this case, the X-direction moving mechanism 13 is configured to drive the X-direction moving mechanism by a stepping motor, and the Y-direction driving motor 15 is configured to drive the Y-direction moving mechanism. The resolution of these X and Y drive motors 13 and 15 is, for example, 800 pulses.

  Next, the control system of the pattern sewing machine 1 will be briefly described. As shown in FIG. 2, the control device 20 includes an input / output interface 21, a computer including a CPU 22, a ROM 23, and a RAM 24, and drive circuits 27 to 29.

  The input / output interface 21 drives a start / stop switch 25, a drive circuit 27 for the sewing machine motor 7, a drive circuit 28 for the X-direction drive motor 13 for driving the X-direction drive mechanism, and a Y-direction drive mechanism. A drive circuit 29 for the Y-direction drive motor 15 to be driven, an X-direction origin sensor 17 for origin setting provided in the X-direction movement mechanism, and a Y-direction origin sensor 18 for origin setting provided in the Y-direction movement mechanism. Etc. are connected. However, the X-direction and Y-direction origin sensors 17 and 18 are proximity sensors, respectively.

  Incidentally, an X encoder 14 is attached to the drive shaft of the X direction drive motor 13. This X encoder 14 is for detecting the actual amount of rotation of the X direction drive motor 13, and is a disk fixed with a drive shaft so as to be rotatable and having slits formed at appropriate intervals in the circumferential direction, a light emitting portion and a light receiving portion. And a detector.

  Therefore, in the X encoder 14, when the light emitted from the light emitting unit passes through the slit of the disk and is detected by the light receiving unit, an encoder signal related to the X direction movement is output to the input / output interface 21, and the X direction drive motor The rotation angle of 13 drive shafts is detected. The drive shaft of the Y-direction drive motor 15 is also provided with a Y encoder 16 configured in the same manner as the X encoder 14, and the encoder signal related to the Y-direction movement is also output from the Y encoder 16 to the input / output interface 21. It has become.

  In this case, the X encoder 14 outputs 800 encoder signals by one rotation of the X direction drive motor 13, and the Y encoder 16 similarly outputs 800 encoder signals by one rotation of the Y direction drive motor 15. Is output.

  The ROM 23 drives and controls various drive mechanisms, and stores a sewing control program for various patterns, a control program for origin setting control unique to the present application described later, and the like. The RAM 24 outputs not only a sewing data memory for storing sewing data to be used for sewing, but also a command number counter 24 a for counting the number of drive pulses for the X and Y direction drive motor 15 and the X and Y encoders 14 and 16. A signal counter 24b that counts the number of encoder signals to be processed, and various memories, pointers, counters, and the like that accommodate the calculation results calculated by the CPU 22 are provided as necessary.

  Next, the origin setting control executed by the control device 20 of the pattern sewing machine 1 and the origin setting operation for the X-direction moving mechanism performed by the X-direction drive motor 13 will be described with reference to the flowchart of FIG. . However, in the figure, reference sign Si (i = 11, 12, 13,...) Represents each step. For the Y-direction drive motor 15, the origin setting control executed simultaneously with the X-direction drive motor 13 is the same as the flowchart shown in FIG.

  When power is turned on to the pattern sewing machine 1 and an origin detection start signal is input to the CPU 22, this control is started. First, the count value CC of the command number counter 24a is cleared and the count value SC of the signal counter 24b is cleared (S11). Next, an origin setting operation (this corresponds to a predetermined operation) is executed (S12).

  However, in this origin setting operation, every time a drive command is output from the CPU 22 to the drive circuit 28 for the X-direction drive motor 13, the count value CC of the command number counter 24a is sequentially incremented, and the X encoder 14 Each time an encoder signal is output to the input / output interface 21, the count value SC of the signal counter 24b is sequentially incremented. When the sensor signal from the X direction origin sensor 17 is switched, the origin setting operation is terminated.

  Next, when the command count value CC and the signal count value SC do not coincide with each other when the origin setting operation is completed (S13: No), a hysteresis elimination operation (see FIG. 4) is executed (S14). ). When this control is started, first, the X-direction drive motor 13 is driven by 4 pulses so as to move the cloth holder 12 in the direction opposite to the final movement direction of the origin setting operation executed in S12 (S21). .

  Subsequently, the X-direction drive motor 13 is driven by 4 pulses so as to move the cloth holder 12 in the opposite direction (S22), and this control is terminated and the process returns to S13 of the origin setting control. Here, the movement operation | movement of the cloth holding body 12 by S21 and S22 is equivalent to a specific operation | movement aspect. Therefore, in the origin setting control, when the command count value CC does not match the signal count value SC (S13: No), S14 is repeatedly executed.

  On the other hand, when the command number count value CC and the signal count value SC match (S13: Yes), the command number count value CC and the signal count value SC are cleared respectively (S15), and this control is finished. Here, the hysteresis elimination control corresponds to the hysteresis elimination control means, S12 of the origin setting control, in particular, S12 corresponds to the origin setting control means, and the control device 20 corresponds to the stepping motor drive control device 20.

  Thus, when the origin setting operation in S12 of the origin setting control is executed, if the driving load of the X-direction moving mechanism is relatively large compared to the driving torque of the X-direction driving motor 13, the origin setting operation ends. Sometimes, the drive shaft of the X-direction drive motor 13 to which the X encoder 14 is attached is delayed by the rotational phase with respect to the normal stop position corresponding to the command pulse from the control device 20 due to the influence of the load during driving. (So-called hysteresis) occurs.

  That is, in such a hysteresis state, the signal count value SC is often smaller than the command count value CC. However, in this way, the command count value CC and the signal count value SC do not match, that is, in a state where hysteresis has occurred in the X direction moving mechanism, the X direction moving mechanism is moved in the opposite direction to the origin setting operation. As a result, the influence of the load applied to the drive shaft of the X-direction drive motor 13 from the X-direction moving mechanism is avoided, and the rotational phase of the drive shaft of the X-direction drive motor 13 is controlled by the command pulse from the control device 20. It matches the regular stop position corresponding to.

  When the hysteresis is resolved in the X-direction moving mechanism, the command count value CC and the signal count value SC are cleared again and a sewing process (not shown) is executed. By adjusting the output timing of the pulse based on the deviation value, the maximum torque by the X direction drive motor 13 can be surely exhibited, and the accuracy of the driving amount of the cloth holder 12 can be remarkably increased. Breakage can be reliably prevented.

  The cloth feeding device has an X-direction moving mechanism and a Y-direction moving mechanism for driving the cloth holding body 12 in the X direction and the Y direction orthogonal to each other in the horizontal plane, and hysteresis is simultaneously applied to the X direction moving mechanism and the Y direction moving mechanism. Since the cancellation of the hysteresis state generated in the X-direction moving mechanism that drives the cloth holder 12 and the cancellation of the hysteresis state generated in the Y-direction movement mechanism are performed simultaneously, the hysteresis in the plurality of drive systems is eliminated. Resolution can be performed quickly in a short time.

  In addition, since the operation (S21, S22) for canceling the hysteresis state is executed in the origin setting operation for setting the origin of the cloth feeding device driven by the X direction drive motor 13 and the Y direction drive motor 15, the power is turned on. In the origin setting operation that is sometimes executed, the hysteresis state of the cloth feeding device can be reliably canceled.

  The origin setting control for performing the origin setting operation ends the origin setting control when the detection signals of the X and Y direction origin sensors 17 and 18 provided in the cloth feeding device are switched. 17 and 18 can be used to set the origin position at the position where the X and Y direction origin sensor 18 is provided.

  Next, a modified embodiment in which the above embodiment is partially modified will be described.

  1) In S21 and S22 of the hysteresis elimination control, the number of pulses for driving the X-direction drive motor 13 is not limited to "4 pulses", and may be less or more. Further, the number of pulses may be configured to be input and set by an operator.

  Furthermore, S22 of hysteresis elimination control can be omitted. However, in this case, it is necessary to move in the reverse direction by the number of pulses driven in the opposite direction in S21 after the origin setting operation is performed and before the start of sewing.

  2] Since the resolution (800 pulses) of the X and Y direction drive motors 13 and 15 and the number of encoder signals output from the X and Y encoders 14 and 16 are the same, “CC = SC "?", But when the number of encoder signals is larger than the resolution of the stepping motor, the determination is made according to "CC = SC × C (where C is a predetermined positive constant)?" It may be.

  3] The origin setting control unique to the present application shown in FIG. 3 is not limited to the origin setting operation, and may be executed immediately after the movement of moving the cloth holding body 12 to the sewing start position or after the sewing is completed. It may be executed when the movement of the cloth holding body 12 is completed.

  4] The origin setting control peculiar to the present application shown in FIG. 3 is applied only to the stepping motor drive control device that drives the cloth holding body 12 that drives the cloth holding body 12 holding the work cloth in the X direction and the Y direction by the stepping motor. The present invention is not limited to this, and can be applied to various stepping motor drive control devices that feedback control the stepping motor using an encoder signal.

  5] The present invention is not limited to the embodiments described above, and those skilled in the art can implement the present invention by adding various modifications without departing from the spirit of the present invention. The present invention includes those modifications.

It is a perspective view of the pattern sewing machine which concerns on embodiment of this invention. It is a block diagram of the control system of the pattern sewing machine which concerns on embodiment of this invention. It is a flowchart of origin setting control. It is a flowchart of hysteresis cancellation control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pattern sewing machine 10 Cloth holding frame 11 Cloth receiving plate 12 Cloth holding body 13 X direction drive motor 14 X encoder 15 Y direction drive motor 16 Y encoder 17 X direction origin sensor 18 Y direction origin sensor 20 Controller 24a Command number counter 24b Signal counter

Claims (6)

In a stepping motor drive control device that performs feedback control of a stepping motor by an encoder signal,
A command number counter for counting the number of drive pulses for the stepping motor;
A signal counter for counting the number of encoder signals;
If the command count value at the end of a predetermined operation of the driven system driven by the stepping motor does not match the signal count value × C (where C is a predetermined positive constant), the stepping motor Hysteresis cancellation control means for eliminating the hysteresis of the driven system by driving the driven system in a specific operation mode;
A stepping motor drive control device comprising:   The hysteresis cancellation control means repeatedly drives the driven system in the direction opposite to the operation direction of the predetermined operation and the opposite direction by the predetermined number of pulses in order to reduce the hysteresis of the driven system. The stepping motor drive control device according to claim 1, wherein the stepping motor drive control device is eliminated.   The driven system has an X-axis drive system and a Y-axis drive system that drive a drive target in an X direction and a Y direction orthogonal to each other in a horizontal plane, and the hysteresis elimination control means includes the X-axis drive system and the Y-axis drive. The stepping motor drive control apparatus according to claim 2, wherein the hysteresis is eliminated simultaneously for the system.   4. The stepping motor drive control apparatus according to claim 1, wherein the predetermined operation is an origin setting operation for setting an origin of a driven system driven by the stepping motor.   The origin setting control means for performing the origin setting operation, wherein the origin setting control means ends the origin setting control when the detection signal of the origin sensor provided in the driven system is switched. 5. A stepping motor drive control device according to 4. A sewing machine comprising the stepping motor drive control device according to claim 1, wherein the driven system is a work cloth feed mechanism.

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