JP3339769B2 - Control device for sewing machine motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a sewing machine motor for controlling a sewing machine motor for rotating a main shaft of the sewing machine.

[0002]

2. Description of the Related Art Conventionally, a control apparatus for a sewing machine motor generally uses proportional integral control (or proportional control) as shown in FIG. 9 in order to rotate a main shaft of the sewing machine at a target constant speed. Here, the sewing machine motor 2 composed of, for example, a DC motor is directly or directly connected to the main shaft 4 via a belt mechanism or a gear mechanism, and drives the needle bar and shuttle mechanism by rotating the main shaft 4. It is supposed to. The speed detection circuit 6 includes a rotary encoder and the like, and detects an actual rotation speed value V of the main shaft 4. The target speed command device 7 includes a switch or a slide switch, and generates a target speed command value R.

A subtractor 8 calculates a speed deviation e from the target speed command value R and the rotational speed command value V,
The proportional integral compensator 10 sets a value proportional to the speed deviation value e and its integral value I as a command torque value Uc as a motor drive circuit 12.
Output to

In this case, assuming that the control gains are k0 and k1, the command torque value Uc is obtained by the following equation.

[0005]

(Equation 1)

The motor drive circuit 12 drives the sewing machine motor 2 so as to generate the command torque value Uc output from the proportional-integral compensator 10. For example, it is driven by a circuit that controls the current so that a current of Uc / k flows through the motor using the command torque value Uc and the torque coefficient k of the motor. Note that P is determined from the command torque value Uc and the rotation speed value V.
The WM pulse width may be calculated and driven by a chopping circuit.

Conventionally, this type of sewing machine motor control device has a problem in that when sewing thick cloth, the sewing needle penetrating force of the sewing machine is insufficient, and the sewing machine motor is locked by resistance of the cloth. Therefore, as disclosed in Japanese Patent Application Laid-Open No. 4-176492, when sewing a thick cloth, the penetration force of the sewing needle of the sewing machine is increased by repeatedly turning off the power supply to the sewing machine motor for a predetermined time.

[0008]

However, in the sewing machine motor control device as described above, when sewing a thick cloth, the energization of the sewing machine motor is repeatedly cut off for a predetermined period of time. The penetration force increases, but the vibration is very large, and there is a risk that the sewing needle of the sewing machine may be broken. In addition, since the magnitude of the penetrating force is set by changing only the time during which the power supply to the motor is cut off, the magnitude of the penetrating force cannot be set finely.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is intended to increase the penetrating force of a sewing needle of a sewing machine when sewing a thick cloth and to easily reduce the magnitude of the penetrating force. An object of the present invention is to provide a control device for a sewing machine motor that can be set finely and has small vibration.

[0010]

In order to achieve this object, a control device for a sewing machine motor according to the present invention comprises a speed detecting means for detecting a rotation speed of a motor or a main shaft of the sewing machine, and the speed detecting means. In order to eliminate a speed deviation value between the detected motor or spindle rotational speed value and the target command value, an operation amount output means for outputting an operation amount, and an operation amount output by the operation amount output means The determination means for determining whether the amount is equal to or more than the amount, and when the determination means makes an affirmative determination, the large operation amount and the small operation amount are alternately output , and the alternate output is determined by the determination unit.
Alternating output means repeated until a negative determination Ri, the exchange
Two types of magnitudes of operation amount output by mutual output means
And setting means for setting each of them. Therefore, it is possible to increase the penetrating force of the sewing needle of the sewing machine when sewing a thick cloth, to reduce vibration, and to use the sewing machine when sewing a thick cloth.
It is easy to finely set the size of the penetration force of the sewing needle
It is possible, Ru can be ensured safety.

[0011]

Further, the control device for a sewing machine motor according to a second aspect of the present invention includes a setting means for setting a period in which the alternate output means outputs two types of large and small operation amounts. Therefore, the magnitude of the penetrating force of the sewing needle of the sewing machine when sewing a thick cloth can be easily and finely set, and the vibration can be further reduced.

[0013]

[0014]

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

FIG. 1 is a schematic block diagram of a control device for a sewing machine motor according to a first embodiment of the present invention. As shown in FIG. 1, the same means as in the prior art are denoted by the same reference numerals, and detailed description thereof will be omitted. The sewing machine motor 2 is connected to the main shaft 4 of the sewing machine, and drives the needle bar and the shuttle mechanism by rotating the main shaft 4.

The control device includes a speed detecting circuit 6 as speed detecting means, a subtractor 8 as manipulated variable output means, a proportional-integral compensator 10, and a torque controller 16 as judging means and alternate output means. It is configured.

The subtractor 8, the proportional-integral compensator 10, and the torque controller 16 are constituted by a one-chip microcomputer 18, and their respective functions are realized by the hardware and software configuration. As shown in FIG. 2, the one-chip microcomputer 18 includes a CPU 20 for performing various arithmetic processes and an RO for storing a processing program and the like.
M22, a RAM 24 for storing variable data, a timer 26 for generating an interrupt process, a speed detection circuit 6, a target speed command device 7, an I / O port 28 for exchanging data with the motor drive circuit 12, and the like. .

The subtracter 8 calculates a speed deviation value e from the target speed command value R given by the target speed command device 7 and the rotation speed value V detected by the speed detection circuit 6. Has become. And the proportional-integral compensator 1
0 is obtained from the above equation 1 from the speed deviation value e and its integral value I.
The command torque value Uc is obtained as shown in FIG.
6 is output.

Next, the operation of the first embodiment will be described.
This will be described with reference to FIGS. 3 and 4 show the main part of the operation procedure in the CPU 20 of the one-chip microcomputer 18. When the processing program stored in the ROM 22 is started, as shown in FIG. 3, first, in step S1 (hereinafter simply referred to as S1; the same applies to the other steps), the command torque stored in the RAM 24 is determined. The value Uc and the count value N are initialized to 0. Next, in S2, the driving of the timer 26 is started. Thus, a timer interrupt is generated at regular time intervals (for example, 8.3 msec). This timer interrupt is continued until the operation of the sewing machine ends, for example, the switch is turned off (S3).

When a timer interrupt occurs, C
The PU 20 executes an interrupt handler as shown in FIG. That is, in S101, the rotation speed value V of the main shaft 4 is detected by the speed detection circuit 6. Next, in S102, S
Using the current rotational speed value V detected at 101 and the target speed command value R, a command torque value Uc is calculated from the above equation 1 and written into the RAM 24.

At S103, the torque controller 16 controls the command torque value Uc and the predetermined torque value Uf (for example, 12 kgf · cm).
Compare. If the command torque value Uc is smaller than the predetermined torque value Uf, the count value N is reset to 0 in S104. Thereafter, in S105, the sewing machine motor 2 is driven so as to generate the command torque value Uc read from the RAM 24 by the motor drive circuit 12.

On the other hand, if the command torque value Uc is equal to or larger than the predetermined torque value Uf in S103, the count value N stored in the RAM 24 is incremented by one in S106. Next, in step S107, the count value N and a are compared. If the count value N is equal to or smaller than a in FIG. 5, the first torque value Ub (for example, 25 kgf · cm) is substituted for the command torque value Uc in S <b> 108 and written into the RAM 24. Here, a is the number of times the first torque value Ub is output. After that, S105 is executed.

If the count value N read from the RAM 24 in S107 is larger than a in FIG.
At step 9, the command torque value Uc is added to the second torque value Us (for example, 1
0 kgf · cm) and write it into the RAM 24. next,
In S110, the count value N is compared with b. If the count value N is equal to or more than b, the count value N is reset to 0 in S111. Here, b is the number of times obtained by adding the number of times of outputting the second torque value Us to a. If the count value N is smaller than b in S110, S111 is skipped and S105 is executed.

Here, how the command torque value Uc is output from the torque controller 16 to the motor drive circuit 12 will be described. Command torque value U calculated in S102
If c is smaller than the predetermined torque value Uf, the command torque value Uc in S102 is output as it is.

When the command torque value Uc calculated in S102 increases and becomes equal to or more than the predetermined torque value Uf, the first torque value Ub is output from the first interruption to the a-th interruption as shown in FIG. Then, the second torque value Us is output from the (a + 1) -th interruption to the b-th interruption.

Further, the first torque value Ub is output from the (b + 1) th interrupt to the (b + a) th interrupt, and the second torque value Us is output from the (b + a + 1) th interrupt to the 2bth interrupt. Output. This is repeated until the command torque value Uc calculated in S102 becomes smaller than the predetermined torque value Uf.

As described above, according to the first embodiment,
When sewing a thick cloth, the penetrating force of the sewing needle of the sewing machine can be increased, and the vibration can be reduced.

FIG. 6 is a schematic block diagram of a sewing machine motor control device according to a second embodiment of the present invention.
As shown in FIG. 6, the same units as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. Setting means 30
Is constituted by a one-chip microcomputer 18, and is set by changing various values of a, b, a first torque value Ub, and a second torque value Us.

Next, the operation of the second embodiment will be described.
This will be described with reference to FIGS.

FIGS. 7 and 8 show a main part of an operation procedure in the CPU 20 of the one-chip microcomputer 18. As shown in FIGS. 7 and 8, the same processes as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

When the processing program stored in the ROM 22 is started, as shown in FIG.
The command torque value Uc, the count value N, and the count value M stored in 24 are initialized to 0. In step S5, the count value M is compared with c. If the count value M is larger than c, the count value M is set by changing the values of a, b, the first torque value Ub, and the second torque value Us ( S6).
Here, c is the number of times determined by the fixed time interval of the timer interrupt, the magnitude of the penetrating force of the sewing needle of the sewing machine, the number of times a, b, and the like. Thereafter, in S7, the count value M is reset to 0. If the count value M is smaller than c, S6 and S7 are skipped.

When a timer interrupt occurs, C
The PU 20 executes an interrupt handler as shown in FIG. As shown in FIG. 8, in S103, the torque controller 16 compares the command torque value Uc with the predetermined torque value Uf. If the command torque value Uc is smaller than the predetermined torque value Uf, S1
At 04, the count value N is reset to 0. further,
In S112, the count value M is reset to 0.

On the other hand, in S103, the command torque value U
If c is equal to or more than the predetermined torque value Uf, R is determined in S106.
The count value N stored in the AM 24 is incremented by one. Further, in S113, the count value M stored in the RAM 24 is incremented by one.

Here, a method of setting the values of a and b, the first torque value Ub, and the second torque value Us in S6 will be described. For example, if you want to increase the penetration force,
By adding a certain number of times to each of a and b, the number of times of outputting the first torque value Ub increases, and the penetration force increases. Note that the penetration force may be increased by increasing the first torque value Ub or decreasing the second torque value Us. Further, the penetration force may be increased by changing and setting all the values of a, b, the first torque value Ub, and the second torque value Us.

In the second embodiment, when the count value M is equal to or larger than c by the CPU 20 of the one-chip microcomputer 18, the a, b and the first torque value U are automatically set.
b, the second torque value Us is set by changing the value, but may be set constantly by a switch or the like.

As described above, according to the second embodiment,
Unlike conventional products, vibration is small when sewing thick fabrics, and the strength of the penetrating force can be set finely, so safety is high, and design suitable for sewing machine applications is easily performed. be able to.

In particular, in each of the above embodiments, since control is performed using the command torque value of the motor, an intuitive and simple design can be performed. Further, since the functions of the respective units are performed by the one-chip microcomputer 18, advantages such as a simplified configuration can be obtained.

In each of the above embodiments, the interrupt processing is performed at fixed time intervals by the timer 26. However, for example, the interrupt processing is performed in synchronization with the pulse output from the rotary encoder constituting the speed detection circuit 6. May be. Further, the speed detection circuit is not limited to the one using the rotary encoder, but may be one using a magnetic sensor or the like. Further, the operation amount output means, the alternate output means, and the setting means are not limited to those using a one-chip microcomputer, and may be constituted by independent circuits.

The present invention is not limited to the above embodiments. For example, the load applied to the sewing needle of the sewing machine is determined based on the torque value of the sewing machine motor 2. You may decide. Also, the driving method of the sewing machine motor 2 is not limited to the DC voltage driving method, and may be a driving method using a commercial AC power supply voltage, and may be appropriately changed and implemented without departing from the gist. is there.

[0040]

As apparent from the above description, according to the sewing machine motor control device of the present invention, it is possible to increase the penetration force of the sewing needle of the sewing machine when sewing a thick cloth. And vibration can be reduced ,
Of sewing needle of sewing machine when sewing thick fabric
Size can be easily set finely and safety
Ru can be ensured.

[0041]

[0042] Further, according to the control apparatus of the sewing machine motor according to claim 2, the vibration from and can be easily finely set the stitch penetration size of the needle of the sewing machine when sewing a thick fabric Can be reduced.

[0043]

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a control device for a sewing machine motor according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of the one-chip microcomputer of the embodiment.

FIG. 3 is a flowchart showing the operation of the CPU of the embodiment.

FIG. 4 is a flowchart showing an interrupt handler of the embodiment.

FIG. 5 is a waveform chart for explaining the operation of the embodiment.

FIG. 6 is a schematic configuration diagram of a control device for a sewing machine motor according to a second embodiment of the present invention.

FIG. 7 is a flowchart illustrating an operation of a CPU according to the second embodiment.

FIG. 8 is a flowchart showing an interrupt handler according to the second embodiment.

FIG. 9 is a diagram corresponding to FIGS. 1 and 6 showing a conventional example.

[Explanation of symbols]

 2 Sewing machine motor 4 Main shaft 6 Speed detection circuit 7 Target speed command device 8 Subtractor 10 Proportional integral compensator 12 Motor drive circuit 16 Torque controller 18 One chip microcomputer 20 CPU 22 ROM 24 RAM 26 Timer 28 I / O port 30 Setting means

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02P 5/00 D05B 69/18

Claims (2)

(57) [Claims] A speed detecting means for detecting a rotation speed of a motor or a main shaft of a sewing machine; and a speed deviation value between a rotation speed value of the motor or the main shaft detected by the speed detecting means and a target command value. An operation amount output unit that outputs an operation amount; a determination unit that determines whether the operation amount output by the operation amount output unit is equal to or greater than a predetermined operation amount; a large operation is performed when an affirmative determination is made by the determination unit. outputting the amount and small operation amount alternately, and its alternate output
Output means for repeating the above until a negative determination is made by the determination means, and two types of large and small operation amounts output by the alternate output means
And a setting means that can set the size of each of the sewing machine motors. 2. The control device for a sewing machine motor according to claim 1, further comprising a setting unit for setting a period during which the alternating output unit outputs two types of large and small operation amounts.