JP2001334093A - Motor control device for sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform sewing at an appropriate speed without the need for halting a motor for a sewing machine even in the case of sewing an object to be sewn with large sewing resistance. SOLUTION: This control device is provided with a command pulse generating part 10 to output a command speed to rotate the motor M for the sewing machine, a speed detecting part 14 to detect the actual speed of the motor M rotated on the basis of the command speed on the basis of the output of an encoder 12, a comparator 18 to output a speed deviation from both a command speed signal generated by a deviation counter 24 and a location amplifier 16 from a command pulse from the pulse generating part 10 and an actual-speed signal from the detecting part 14, and a seed amplifier 20 to control the motor M so that the seed deviation becomes zero. The control device is provided with both the deviation counter 24 to compute a locational deviation from the difference between the pulse of the pulse generating part 10 and the pulse of the encoder 12 and a deviation monitoring control part 26 to compare the locational deviation with a reference value and to lower the command speed when the deviation exceeds the reference value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine motor control device, and more particularly, to a sewing machine motor which is suitably applied when the sewing motor is appropriately rotated regardless of the magnitude of a sewing resistance caused by a difference in a sewing product. The present invention relates to a motor control device.

[0002]

2. Description of the Related Art Conventionally, in a so-called cycle sewing machine in which a sewing operation is performed in the order of acceleration, constant speed, and deceleration from the start of sewing in accordance with a command speed shown by a dashed line in FIG. In this case, the actual speed changes as shown by the solid line in the figure, and the position deviation becomes an operation waveform that changes as shown by the broken line. However,
The unit of speed is rpm, and the unit of position deviation is pulse (pul)
se). Further, the command speed is given by the number of pulses per unit time output from a command pulse generator, which will be described later, that is, the frequency. The shorter the interval, the shorter the pulse.

When the normal sewing as shown in FIG. 5 is performed, the actual speed follows the command speed slightly in the acceleration section, and catches up after reaching the constant speed section. Is controlled so as to approach while increasing or decreasing with respect to the command speed. At this time, the position deviation amount also stops rising at a certain value, and is controlled while stably moving up and down.

However, when sewing a cloth having a large sewing resistance due to a thick sewing material or the like due to the above-described cycle sewing machine, a phenomenon occurs in which the rotation speed of the sewing machine motor cannot be increased to a commanded speed. The deviation may continue to increase.

Therefore, conventionally, when such a phenomenon occurs, as shown in FIG. 5, an overload abnormality detection level, which means that the positional deviation is excessive, is set. When the positional deviation exceeds the level, the sewing machine motor is stopped and the operator is notified. That is, as shown in the operation waveform of the sewing machine motor similar to that of FIG. 5 when the overload abnormality occurs in FIG. 6, the sewing machine motor is stopped at the time of occurrence of the abnormality indicated by the arrow.

[0006]

However, in the case where the sewing machine motor is stopped in the middle due to the sewing of the sewing product having a high sewing resistance as described above, it is necessary to perform the sewing once to complete the sewing product. After the thread was unwound, it was necessary to lower the set value of the motor command speed using the operation panel or the like, and then re-sewing.

Further, in order to prevent the phenomenon that the sewing machine motor is stopped halfway, as described above, before sewing, an operator sets an appropriate motor command speed set value suitable for the sewing product. The operation of inputting using an operation panel or the like was required, which was very troublesome.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described conventional problems. Even when sewing a sewing product having a large sewing resistance, the sewing machine motor can be stopped without stopping.
An object of the present invention is to provide a sewing machine motor control device capable of sewing at an appropriate speed.

[0009]

According to the present invention, there is provided a commanding means (10) for outputting a command pulse for commanding a rotation amount and a speed of a sewing machine motor, and a sewing machine motor rotating based on the output command pulse. Rotation amount detection means (12) for detecting the rotation amount; deviation calculation means (24) for calculating a deviation between the command rotation amount commanded by the command means and the actual rotation amount detected by the rotation amount detection means; Wherein the output frequency of the command pulse output from the command means is reduced when the deviation calculated by the deviation calculation means exceeds a predetermined reference value. This problem has been solved by providing a deviation monitoring control means (26) for causing the above.

That is, in the present invention, when the position deviation detected (calculated) at the time of sewing exceeds a reference value set in advance to an appropriate value, the target command speed is reduced. In addition, since the load on the sewing machine motor can be prevented from becoming excessive, the sewing operation can be continued at an appropriate rotation speed without stopping the sewing machine motor.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a circuit block diagram showing an outline of a sewing machine motor control device according to an embodiment of the present invention.

The control device according to this embodiment includes a command pulse generator (command command) for outputting a command speed corresponding to a target speed set when rotating a sewing machine motor (servo motor) M as the number of pulse signals per unit time. Means) and the actual speed of the sewing machine motor M rotating based on the command speed is detected as the number of pulse signals per unit time outputted from an encoder (rotation amount detecting means) 12 synchronized with the motor M. At the same time, a speed detection unit 14 that converts and outputs a signal corresponding to the actual speed and a pulse signal output from the command pulse generation unit 10 perform a process described later to output a signal corresponding to the command speed. Position amplifier 16
And a comparator 18 for comparing a command speed input as a signal from the position amplifier 16 with an actual speed input as a signal from the speed detector 14 to calculate a speed deviation, and eliminating the calculated speed deviation. And a speed amplifier 20 for multiplying the deviation signal from the comparator 18 by a predetermined gain to output a control signal.
The torque converter 22 is controlled based on the control signal from the controller to control the rotation speed of the sewing machine motor M to follow the command speed.

In this embodiment, the position deviation (rotation amount deviation) is determined by the number of pulses (designated rotation amount) input from the command pulse generator 10 and the number of pulses (actual rotation amount) input from the encoder 12. ), A deviation counter (deviation calculating means) 24 that calculates in real time, a monitoring function that compares the calculated position deviation amount with a predetermined reference value that is set in advance, and monitors the calculated position deviation. When the deviation exceeds the reference value, the deviation monitoring control unit (deviation monitoring control means) 26 having a change function for lowering the command speed set at that time for the command pulse generation unit 10 is provided. Have.

A signal corresponding to the position deviation output from the deviation counter 24 in real time is input to the position amplifier 16, multiplied by a predetermined gain by the amplifier 16, and output to the comparator 18. The signal is converted into a signal corresponding to the command speed.

In the present embodiment, the deviation monitoring control unit 26 having the command speed changing function includes a deviation counter 24.
If the position deviation calculated in step (1) is smaller than the reference value, control for increasing the command speed is performed. As will be described in detail later, the reference value for calculating the position deviation is set to a value lower than the abnormality detection level for stopping the control as an overload abnormality described in FIGS. 5 and 6. .

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

A specific example of the control operation is a case in which the sewing resistance is large due to, for example, the entire sewing material being thick as in the case shown in FIG. FIG. 3 shows a control operation waveform of the sewing machine motor corresponding to FIG. 6 in this case.

In this embodiment, as described above, a reference value to be compared for monitoring the position deviation is set in advance, and a broken line indicated by reference numeral A in FIG. 3 corresponds to this reference value. . Since the reference value A is lower than the overload abnormality detection level, safety can be ensured, and the reference value A is experimentally set in consideration of sewing efficiency.

According to the flowchart, the sewing machine motor M is started (step 2), and the command pulse generator 10 starts outputting command pulses (step 4). The output pulse signal is supplied to the deviation counter 24.
The position deviation amount is calculated in real time as the difference from the pulse signal input from the encoder 12 and the position deviation monitoring control unit 26 compares the deviation amount with the reference value A. Is performed (step 6).

If the positional deviation exceeds the reference value A (Yes in step 6), the command speed output from the command pulse generator 10 (the number of command pulses per unit time)
, That is, the output frequency of the command pulse output from the command pulse generator 10 is reduced (step 8). Conversely, if the value falls below the reference value A (No in step 6), control is performed to increase the command speed, that is, the output frequency of the command pulse output from the command pulse generator 10 is increased (step 10).

As described with reference to FIG. 6, the above control operation is continued until the end of the sewing range unless the position deviation exceeds the overload abnormality detection level and overflows (No in step 12). (Step 14,
16). If an abnormal situation occurs and an overflow occurs in step 12, the sewing machine is stopped for safety as in the prior art (step 18).

As described above, when the positional deviation exceeds the reference value A, the command speed is reduced, and when the position deviation amount falls below the reference value A, the command speed is increased. By performing the rotation control of the sewing machine motor based on the speed, it is possible to perform appropriate control based on the operation waveform as shown in FIG.

That is, since the sewing material has a high sewing resistance,
Since the actual speed (solid line) does not reach the commanded speed (dashed line), the positional deviation amount (dashed line) gradually increases. If the position deviation amount thus increased exceeds the value of the reference value A at the point of time T1 marked with a vertical line, control for reducing the command speed is performed. When the command speed decreases and the number of rotations at which the motor can rotate can be reached, the positional deviation starts to decrease, and at time T2, the reference value A
It becomes smaller than the position. When the position deviation amount becomes smaller than the value of the reference value A at the time point of T2, the control is performed in the reverse direction to return the commanded speed to the original rotation speed.

Similarly, at each subsequent time indicated only by the vertical line, the command deviation is changed depending on whether the position deviation is larger or smaller than the value of the reference value A. It can be controlled so that it goes up and down around the value of A. In this case, as indicated by the max rotation speed in the figure, the initial command speed corresponding to the constant speed in the case of a normal sewing product becomes the maximum value, and control is performed so as not to exceed this maximum value.

In this case, the command speed output from the command pulse generator 10 as the number of pulses per unit time is as shown in the lower part of FIG. This means that the pulse waveform is changed over time. Also, the actual operation pulses listed below are
When the control is performed by outputting the “command pulse”, the pulse corresponds to the pulse waveform output from the encoder 12.

FIG. 4 is a sewing machine operation waveform showing a specific example in the case where there is a section where the sewing resistance is large in a part of the sewing section. Since this is the same as the case of the control shown in FIG. 3, the details will be omitted, but if the control is performed to change the command speed depending on whether the position deviation amount is larger or smaller than the reference value A, This is an example of the case where the command speed is reduced to the operable speed only in the section with large resistance such as the overlapped sewing part in the middle, so that the motor can be controlled at the optimum rotation speed for the resistance of the sewing product. is there.

As described in detail above, according to the present embodiment,
The following excellent effects can be obtained.

(1) The sewing machine speed (command speed) is automatically reduced even for a sewing product having a large sewing resistance, so that the sewing machine does not stop halfway, so that a re-sewing operation is not necessary.

(2) The operator does not need to input the sewing machine speed from a panel or the like in advance according to the sewing product.

(3) Even a sewing product having a large resistance can be sewn at an optimum sewing speed within an allowable range, so that the cycle time is shorter than when the operator inputs the sewing speed according to the sewing product. Improvement can be achieved.

Although the present invention has been specifically described above, the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the gist thereof.

For example, the specific configuration of the sewing machine motor control device of the present invention is not limited to the one shown in the above embodiment.

As shown in the above embodiment, the command speed is not limited to the case where the position deviation amount is repeatedly reduced and increased while comparing the position deviation amount with the reference value.
The value may be maintained.

[0035]

As described above, according to the present invention,
Even when sewing a sewing product having a large sewing resistance, sewing can be performed at an appropriate speed without stopping the sewing machine motor in the middle.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram illustrating an outline of a sewing machine motor control device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment.

FIG. 3 is a diagram showing a control operation waveform of the sewing machine motor together with the effect of the present embodiment.

FIG. 4 is another diagram showing the control operation waveform of the sewing machine motor together with the effect of the present embodiment.

FIG. 5 is a diagram showing a control operation waveform of a sewing machine motor by a conventional control device in a normal operation.

FIG. 6 is a diagram showing a control operation waveform of the sewing machine motor by the conventional control device at the time of abnormal operation.

[Explanation of symbols]

 M: Servo motor (sewing machine motor) 10: Command pulse generator 12: Encoder 14: Speed detector 16: Position amplifier 18: Comparator 24: Deviation counter 26: Deviation monitoring controller

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G05D 3/12 306 G05D 3/12 306Z H02P 5/00 H02P 5/00 PF term (Reference) 3B150 CA03 CE03 CE23 GD14 GD22 JA08 LA85 LA88 LB01 MA02 MA15 NA74 NC07 PA03 QA06 QA07 5H209 AA20 BB08 CC01 DD06 EE20 GG01 HH04 HH15 5H303 AA30 BB01 BB06 BB14 DD01 EE10 FF09 HH01 JJ02 KK12 KK14 KK18 KK18 KK18 KK18 KK18 KK18 KK18

Claims (3)

[Claims] 1. A command means (10) for outputting a command pulse for commanding a rotation amount and a speed of a sewing machine motor, and a rotation amount detection for detecting a rotation amount of the sewing machine motor rotating based on the output command pulse. Means for calculating the deviation between the commanded rotation amount commanded by the commanding means and the actual rotation amount detected by the rotation amount detecting means; A controller for controlling the sewing machine motor, wherein, when the deviation calculated by the deviation calculating means exceeds a predetermined reference value, a deviation monitoring control means (26) for lowering an output frequency of a command pulse output from the command means.
A sewing machine motor control device comprising: 2. The apparatus according to claim 1, wherein said deviation monitoring control means increases an output frequency of a command pulse output from said command means when the calculated deviation is smaller than said reference value. Sewing machine motor control device. 3. The sewing machine motor control device according to claim 1, wherein the reference value is set to a value lower than an abnormality detection level for stopping control as an overload abnormality.