JPS60141181A - Speed controller of motor - Google Patents

Abstract

PURPOSE:To reduce the number of parts and to eliminate the regulation of the minimum speed of a motor by comparing the rotating speed of a motor with the target rotating speed by a microcomputer, and controlling the rotating speed of the motor. CONSTITUTION:The energizing time of a motor M per period of a power source in response to the value of a variable resistor VR in the normal load of a motor M is stored in a ROM1 of a CPU, a time TA obtained from the target rotating speed set by a variable resistor VR is stored in a ROM2, and a time TB obtained from a signal from rotating speed detecting means of a slit disc P is stored in a ROM3. A value obtained by subtracting the time TB by the time TA and the value obtained by adding the energizing time stored in the ROM1 are as the energizing time of the motor M, thereby controlling the energization of a transistor Tr.

Description

[Detailed Description of the Invention] [Technical Field] The present invention provides a method for smoothly rotating a motor, such as a motor used in a sewing machine, whose rotational speed varies over a wide range and whose load torque fluctuates widely. The present invention relates to a speed control device for a motor.

[Background technology] Conventional sewing machine control circuits use operational amplifiers, transistors,
Thyristors, etc. are used. In addition, in conventional devices, to set the minimum speed of the motor, the output voltage of the integrating circuit and the induced voltage of the motor were compared, and based on this result, the time to energize the motor was determined. When the motor speed is slow, the induced voltage of the motor becomes low, and it is necessary to set the resistance value of the variable resistor in response to this low voltage.

[Problems with Background Art] As described above, the conventional technology has a problem of high cost due to the large number of parts. Furthermore, it is necessary to adjust the minimum speed, which leaves a problem that the manufacturing stage remains complicated.

[Purpose of the Invention j The present invention has been made in view of the above-mentioned problems of the conventional art, and it reduces the number of parts when controlling the speed of a motor, and eliminates the need to adjust the minimum speed of the motor. It is an object of the present invention to provide a motor speed control device that can eliminate complications in the manufacturing stage by doing so.

[Summary of the Invention] The present invention sets a target rotational speed of a motor using a variable resistor, detects the rotational speed of the motor using a slit disk or the like linked with the motor, and combines this detected value with the target value.
The comparison is made using a microcomputer, etc., and the rotational speed of the motor is controlled.

[Embodiments of the invention] FIG. 1 is a circuit diagram showing one embodiment of the present invention.

In this figure, a slit disk P attached to the shaft S of a motor M is provided with ten equally spaced slits, and as the motor M rotates, the passage of light from the photointerrupter PI is intermittently blocked. When M rotates once, photointerrupter P'l outputs 10 pulses, which are input to input terminal x1 of ICQ5 via inverter Q2. Normally, input terminal x1 of ICQ5 is connected to output terminal X, and when motor M rotates, pulses corresponding to the rotation are input to boat P20 of CPU QO. CPLI QO performs various controls according to information from each input port, and provides ICQI for boat expansion.
are connected to the CPU, , and QO through a data bus.

CB1 of ICQl for boat expansion is connected to inverter Q4. A pulse synchronized with the commercial power supply is input to the inverter Q4 through the resistor R1 and the bridge diode BD1. In response to the pulse input from inverter Q4, from I RQB to CP of ICQl for boat expansion.
An interrupt signal is transmitted to [RQl of U QO.

IC number 05 is an IC for setting the CPU QO operation mode. When the power is turned on, charge is accumulated in capacitor C1 through resistor R3, so the potential of capacitor C1 lags behind the +V potential. Rise. For this reason, when the power is turned on, CPLJ Qo is reset, and the output terminals X, Y, and Z of ICQ5 are respectively connected to terminal XO.
, YO, and ZQ. In addition, terminals XO, Y0, 2
0 is given a potential for determining the operation mode of CPLI Qo. Thereafter, the potential of capacitor C1 rises, and the X, Y, and Z terminals of ICQ5 are connected to terminals X1. Y
1 and Zl, respectively.

The A/D converter Q6 receives at its input terminal AO a voltage that changes depending on the value of the variable resistor VR for setting the rotation speed, and sends a serially digitized signal to the CPLJ Qo. ADCLK input of A10 converter Q6 is connected to CPU Q through ICQ5.

is connected to baud 1-P22. , CPU QO are synchronously generating pulses from boat P22.

In synchronization with the above pulse, the A/D converter Q6 outputs CPtJ.
When QO boat P24 changes from 1 to O, D
The value of the variable resistor VR is converted into an 8-bit digital value and output from the ATA OUT to the CPjJ QO boat P22. On the other hand, CPU QO baud 1-P23
The data of the variable resistor VR input from is held in the RAM3.

A voltage obtained by rectifying the commercial power supply with the bridge diode BD2 is supplied to the motor M, and the voltage between the motor M and the 1-transistor T
r are connected in series. According to the given flow angle,
The rotational speed of the motor M is controlled by switching the transistor Tr.

A photocoupler PC is used in the base circuit of the transistor Tr.
A phototransistor is inserted, and the first Kabra PC
When a current is passed through the light emitting diode side, the transistor Tr is turned on and the motor M is energized.

The light emitting diodes of Fo 1 to Cabra PC are connected to inverter Q.
3. CPIJ Qo boat P21 via ICQ5
The motor M is controlled by receiving signals from the motor M.

The ROM1 (first storage means) stores the relationship between the value of the variable resistance VR at a normal load of the motor M and the rotational speed of the motor M. Here, the normal load is 0.3
mmPi! This refers to the load on the motor M when sewing two layers of cloth having a thickness of 100 mm, and the content thereof may be determined as necessary. In other words, the ROMI stores the time required to energize the motor M per cycle of the power supply in order to operate the motor M at a target rotational speed.

FIG. 2 shows the relationship between the energization time of the motor M and the rotational speed of the motor M' when the sewing machine is operated under a normal load.

FIG. 3 is a graph showing the relationship between the sliding amount d of the variable resistor VR and the data obtained by digitizing this slide ff1d.

The ROM2 (second storage means) stores data obtained from the target rotation speed set by the variable resistor VR. The ROM3 (third storage means) contains a slit disk P.
Data obtained from rotational speed detection means such as the above are stored. Data in ROMI is stored as fixed data at addresses $FOOO to $FOOF, data in ROM2 is stored in addresses $FO10 to $FOIF, and data in ROM3 is stored in addresses $FO20 to $FO3F.

FIG. 4 shows the ROMI, ROM2. This figure specifically shows the relationship between addresses and data in the ROM3.

The data in the variable resistor VR is 8 bits, and if one piece of data is composed of 1 byte, 256 bytes of information are required, so the data is compressed and the data in ROM1 and ROM2 are composed of 16 bytes each. This uses the data obtained by incrementing the index register IX for the upper 4 bytes of the 8 bits of data of the variable resistor VR, and performs linear interpolation with the lower 4 bits of the variable resistor VR. Insert the energization time data and rotation speed data of the corresponding motor.

The detected rotation period of the motor M is displayed in 2 bytes, and since the rotation speed is inversely proportional to the rotation period, the smaller the rotation period, the more accurate data is required.

Therefore, ROM3 is $F020~$FO'2F,
It consists of two parts: $F030 to $FO3F. If the upper byte of the rotation period of the motor is smaller than $10, from $FO20 to $FO2F, and if the upper byte of the rotation period of motor M is larger than $10, $FO30
~ Get data from $FO3F by linear interpolation.

Full-wave rectification of the commercial power supply with bridge diode BD1,
After passing the N voltage divided by resistors R1 and R2 through inverter Q4, it is input to CB1 of ICQl for boat expansion. In this boat expansion ICQl, Ql becomes 0 when the signal input to its CB1 rises. When the IRQl becomes O, a power synchronization interrupt is entered.

FIG. 5 is a diagram showing a timer control circuit built into the CPU QO. Free running counter F
RC is a 16-bit power counter that counts up according to the basic clock of CPLI QO, and here counts up every 1 μsec. The 8-bit timer control register F outputs a signal to the boat P21, changes the signal from the boat P20, and controls the CPU QO.
Controls internal interrupt IRQ2.

In the 16-bit register ICR, when the signal on the port P20 changes as shown in IEDG of the timer control register F, the edge detection section operates and the value of the counter FRC is held in the register ICR, and at the same time, the ICR of the timer control register F is changed. Set C'F. EICI of timer control register F is a bit that controls whether or not to generate IRQ2 when the signal of boat P20 changes as shown in IEDG.If this bit is set, ICF is set. Sometimes I
Let RQ2 be generated.

Here, IEDG of timer control register F is set to 1, and when the signal of boat P20 rises and changes,
The edge detection section works and generates ■RQ2.

The value of the 16-bit alarm conveyor register OCR and the value of the free running counter FRC are compared in the data comparison section, and when the two values match, the data comparison section selects the GK of the D-type flip 70-tube. is output to. When a pulse is input to this CK, the value of 0LVL of the timer control register F is output to the Q of the D-type flip-flop.

Bitl Boat 2 data direction register G
is set to 1, so the value of 0LVL of timer control register F is output to boat P21.

Next, the operation of the above embodiment will be explained.

First, in order to operate the motor M at a rotational speed of R1 when the sliding amount of the variable resistor VR is set to dl, the following settings may be made in advance. In other words, from Fig. 2, the motor energization time to operate the motor M at the rotational speed R1 is T.
1, and from Figure 3, the 8-bit digitized variable resistor V when the sliding amount of the variable resistor VR is dl.
Observe that the data in R is $Y1. Therefore, R
Store the data of time T1 in the part corresponding to $Y1 in OM1. In this way, when the sliding amount of variable resistor VR is set to dl, if the load is normal, the rotation speed R1 Motor M performs the rotation.

Then, determine the target rotation speed over the entire sliding range of the variable resistor VR, and use Figures 2 and 3 to determine the motor By storing data on the energization time of M in the ROMI, the target rotational speed can be obtained in the ROM1 according to the sliding amount of the variable resistor VR.

, F, in the case of a normal load, the motor M rotates at the target rotational speed based only on the data in the ROM1. However, when sewing thick materials or when rotating the motor M slowly, the motor load changes greatly during one rotation of the sewing machine, resulting in a decrease in rotational speed or uneven rotational speed. In order to eliminate these problems, when the rotation of motor M becomes slow, it is necessary to
It is sufficient if the energization time to the motor M is set longer per cycle.
Conversely, when the rotation of the motor M becomes faster, it is sufficient to shorten the energization time to the motor M per revolution of the commercial power supply. In this way, feedback is required to reduce changes in rotational speed.

This feedback needs to be adjusted depending on the target rotation speed and the actual rotation speed. In the above embodiment, the magnitude of feedback is determined by subtracting the data obtained from the actual rotational speed (data in ROM3) from the data obtained from the target rotational speed (data in ROM2).

Here, if the target rotation speed is A and the actual rotation speed is B, then what is the ideal feedback at this time? Let I (time, :m5ec) be TF. This ideal feedback time TF can be determined as follows.

It is TF-TB-TA.

The time 1111TA is the time measured from the target rotation speed A, and the time TB is the time measured from the actual rotation speed B. In other words, the time TA is determined according to the sliding amount of the variable resistor (R), and the time TB is determined according to the period of the slit S.

FIG. 6 is a graph showing the ideal feedback time determined through experiments for the rotational speeds A and B of the motor M.

The element that stores data on time TA with respect to target rotational speed A is ROM2, and the element that stores data on time TB with respect to the period of slit S is ROM3.
It is.

FIG. 7 is a flowchart showing the operation of the above embodiment. Figures 7(a), (b), and (c) are respectively ICF
3 is a flowchart showing an interrupt, a main routine, and a power synchronization interrupt.

[In the CF interrupt, the rotation period can be detected by subtracting the previous [CR value from the current IOR value within a unit time, and the value is stored in RAM1.]
Store in. After that, as the current ICR value, RA
Store it in M2 and hold it until the next ICF interrupt.

In the main routine, to calculate the energization time of the motor M in one cycle of the commercial power supply, that is, to calculate the ideal feedback time, the following processing is performed.

The time of 1/10 rotation of the slit disk S is loaded, and data from the ROM 3 is extracted according to the rotation period. Store the retrieved data in RAM5. Next, load the data of variable resistor VR, and according to this data, ROM2
data, and store this extracted data in RAM.
Store in 6. On the other hand, from the data of variable resistor VR, RO
The data of M1 is extracted and this data is stored in RAM7. Then, the data in RAM5 is subtracted from the data in RAM6, and the result is R, A M7. , and store the addition result in RAM8. The data stored in the RAM 8 is the energization time.

In the power synchronization interrupt, if the frequency of the commercial TI source is 50
If it is H2, use the data in RAM8 as is, and if the frequency of the commercial power supply is 60Hz, change the data in RAM8 to 0.
．． Multiply it by 83 before using it. This is so that even if the commercial power frequency becomes 6082, the same rotational speed as when it was 50H2 can be maintained.

C as a calculation means for obtaining the memory contents of the RAM 8.
PU QO is used, and the internal timer of this CPU QO calculates the power frequency from the difference between the internal timer value at the previous power synchronization interrupt and the internal timer value at the current power synchronization interrupt. The *m frequency is detected, and the time during which the motor M is energized is controlled according to this *m frequency.

ROM2. Feedback can be set appropriately according to the difference in rotational speed using the data in ROM3, so motor M
Needless to say, there is no need for adjustment at the high and medium speeds of the motor, and since there is no need for adjustment at the lowest speed of the motor, the complexity of adjustment at the manufacturing stage of the sewing machine can be eliminated. Also, R
The rotational speed of the motor M can be set steplessly using OMI data.

Note that the data in ROMI and the data in ROM2 are extracted with the same value of the variable resistor VR, and are respectively extracted from RAM7. R
Stored in AM6. Therefore, ROM1 and ROM
If the values of the two ROMs 2 and 2 are added from the beginning and the data is stored in another ROM, it becomes unnecessary to use ROM1 and ROM2 if one other ROM is provided. In other words, the number of ROMs can be reduced by one.

[Effects of the Invention] As described above, the present invention can reduce the number of parts when controlling the motor speed of a sewing machine, and eliminates the need to adjust the minimum speed of the motor. This has the effect of eliminating the complexity of adjustment at the sewing machine manufacturing stage.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a graph showing the relationship between the energization time of the motor M and the rotational speed of the motor M when the sewing machine is operated under a normal load. 3
The figure is a graph showing the relationship between the sliding amount of the variable resistor and the data obtained by digitizing this sliding amount, and Figure 4 is the ROM
Figure 5 is a diagram showing the timer control circuit built into the CPU, Figure 6 is a graph showing the relationship between motor rotation speed and feedback time, and Figure 7 is a diagram showing the memory contents of 1 to 3. 7 is a flowchart showing an example operation, and FIGS. 7(a), (b), and (c) are respectively ICF
3 is a flowchart showing an interrupt, a main routine, and a power synchronization interrupt. M...Motor, S...Shaft, P...Slit disk, Qo...CPU, Ql...Port expansion IC
, Q2... Inverter, Q3... Inverter, QO
...A/D converter, PC...photocoupler, VR/
...Variable resistance. Figure 7 tσ lb (C)

Claims (1)

[Claims] (1) A rotational speed detection means for detecting the rotational speed of the motor is provided, a variable resistor is provided for setting the rotational speed of the motor to a target rotational speed, and the value of the variable resistance and the rotation of the motor at a normal load of the motor are provided. A first storage means is provided for storing the relationship with the speed, and a second storage means is provided for storing data obtained from the target rotation speed set by the variable resistor, and the second storage means is provided for storing data obtained from the rotation speed detection means. A third storage means is provided, and an arithmetic means is provided for adding the data of the first storage means to a value obtained by subtracting the data of the third storage means from the data of the second storage means, and the output signal of the arithmetic means is A motor speed control device comprising a motor energization means for controlling the rotational speed of the motor by controlling the energization time to the motor accordingly. (2. Claim 1 provides that a CPU is used as the calculation means, a power supply frequency is detected by an internal timer of the CPU, and the time for energizing the motor is controlled according to this power supply frequency. Characteristic motor speed control device.