JPS6046800A - Step motor control circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a stepper motor control circuit having a plurality of windings that can be selectively routed from one end to the other for rotating a rotor to a desired angular position. The present invention relates to a control circuit having a power supply connected to the winding for controlling the winding.

Back of the Invention Jj1 and Problems The problems that arise when controlling the rotor without the aid of a transducer that follows the rotor are as follows: , the rotor vibrates about 4 degrees from the designated stop position 11'21', and there is a considerable influence between <z 1141 of this /C angle advance cycle. This issue is particularly problematic because elements that change their position continuously (for example, flexible brake pad type characters JL + holding wheels used in high-speed typewriters and printing devices) , or magnetic medium V (magnetic hemispheres 1 to 1 for loading and reading data)
This is a case where a step motor is used as a means of positioning.

In the conventional 4.1'11 construction for damping the vibrations of the rotor of a step motor, a metal ring is fixed to the motor shaft so that the ring rotates together with the motor shaft. The ring is rotatable within a lubricating oil-filled cavity housed in a stationary cylindrical container.

This mechanical braking action only partially reduces the vibrations of the rotor; however, it is disadvantageous to considerably increase the associated quality, thereby impairing the efficiency of the motor. .

OBJECTS/SUMMARY OF THE INVENTION It is an object of the present invention to assist in controlling or damping the vibrations of the rotor of a stepper motor using electronic circuitry associated with the circuitry that controls the motor from pylon 1.

In order to achieve this object and to eliminate the drawbacks of conventional mechanical braking arrangements, a circuit according to the invention is characterized in that a braking circuit is connected to one of the windings and a signal representative of the rotor's angular velocity is detected. At the same time, it is connected to a power supply device to adjust the power supplied to the other windings so that the vibrations of the rotor are damped during the rotor operation at a desired angular position.

DESCRIPTION OF THE EMBODIMENTS In a single diagram + rc, the present invention is embodied in a Buhi electronic circuit J
-0 is for controlling the step motor 11, and the control circuit 12, which is a component thereof, controls the winding of the motor 11 based on the data given by the control circuit J3, which is composed of, for example, a micro sensor. Control pulse to line (
(Details will be described later) can be generated. The auxiliary circuit 14 is connected to the step motor 1, the control unit 13, and the control circuit 12.

! Before entering into a detailed explanation of the moving circuit 14, a general explanation regarding step motors will be briefly explained.

Figure 2 is a circuit diagram of a single-stage, four-phase step motor. The stator J5 of the step motor is provided with windings A, A, J3 and magnetic pole pieces 16, 17, 18 and 19 with positive windings -fI-.

A rotor 20id made of a permanent magnet is attached to a motor shaft 21 coaxial with the stator 15.

One end of the windings A, A, , B and B is the open/close switch 22
．． 23. Power supply (power supply) via 24 and 25 respectively
It is connected to VA, and the other end is grounded.

Normally, in order to bring the rotor 20.r to rest, the switch corresponding to the winding associated with the desired resting position of the rotor is fully closed. For example, to hold rotor 20 between pole pieces 16 and 18, switch 22 is closed and winding A is de-energized to energize pole pieces 16 and 18 to the south and north poles, respectively.

To rotate the rotor 20 with respect to the stator 5, other windings are sequentially energized. 1] When the switch 24 is closed and the switch 22 is opened to energize the winding B, the rotor 20 rotates by one step in the counterclockwise direction and reaches the position 20' shown by the broken line in FIG. Proceed to. But winding A,! :
When B is activated at the same time, the rotor 20 assumes a position 20'' between the magnetic pole pieces 16 and 17. It is held stationary by the resultant force of the two forces generated by the magnetic field.This stopping position is therefore preferable to the stopping position in which the rotor 20 is completely opposite one of the pole pieces of the stator 15.

As can be seen from the figure, in a unipolar step motor, the direction of current flowing through all the windings is always the same.

Unlike FIG. 2, FIG. 3 is an equivalent circuit diagram of a double camellia-shaped step ball. stator 3 of the step motor],
There are provided magnetic 41V pieces 32, 33, 34 and 35 around which windings A, B, A and B are respectively wound.

The rotor 36trJ is attached to the shaft 37 with a permanent magnet.

Windings A and A are connected in series with each other and the -'1fi
i is connected to switch 41, and the other end is connected to switch 42. Windings B and B are also connected in series! -ψ product; (Ij switch 43 and fJ switch 44
Vc is connected. Each switch 41, 42, 43 and 44v'i has three f1 lines 11''1''σ, h and C. (3' (In position a, switch 11. Force supply section (
Power supply) Connected to VA, open at 1 standing B, position @C
Then it will be grounded. In this type (bipolar type) step motor, C is the winding A.

Current flows through B, A and B in both directions.

In the condition shown in FIG. 3, switches 43 and 44 are open and no current flows through windings B and B, -force, switch 41.
is grounded and switch 42 is connected to power supply VA, so current flows through windings A and A, and rotor 36 is connected to N4.
ψ is placed at a position opposite to the front surface of the magnetic pole piece 32.

Rotate the rotor 36 clockwise in 1/2 steps (1 fit 3)
6"), move switch 43 to position a and switch 44 to position C to apply current to windings B and B.

Both monopolar and bipolar motor types can be controlled so that the rotor advances J/2 stenopules or one step at a time.

One of the widely used control methods for controlling step motors (-1) is a method used in constant current fully intermittent or "chopper" mode.

By using the constant current supply mode, one day within the J11 range, it is possible to output the speed and the actual torque.
By supporting the power output (rather than '), the ratio between the available output and the supplied power can be increased.

An example of the control circuit 45 is shown in FIG. Here, four pairs of l
・Ran resistors (50 and 51), (52 and 53), (54
and 55) and (56 and 57) are used, and their bases are logic signals F i , F 2 , F 3
, F'4, F5.

F6. F7. F8 is supplied respectively. These transistors act as switches for selectively passing current through windings A, A, B and B.

Signals F1 to F811-J are the outputs of a series of AND gates 58 and 58. These elements receive, as their input signal, a signal A which is given by the decoder 46 based on the data VC sent from the control unit 3 via the channel 57 (see FIGS. 1 and 4).

■Electric 'B, FC:, FD, and signals INl and N given by two flip-flops 48 and 413, respectively.
I'll take the second one. Decoder 46 is of a known type and will therefore not be described in detail below.

The circuit 45 & further includes an oscillator 60 which provides timing pulses O8 at a constant frequency, for example 22KH7. Both flip-flops 48 and 49 (d) are set by this signal O8 and reset by the signals RESI and RES2 output by the two comparators G1 and C2, respectively. The signal “M+.” is 1, and the other human power is, respectively.
This is a signal taken out from one end of resistors R31 and R82.

g anti-R31,! : Two resistors R are connected between comparator C1.
A voltage divider circuit consisting of R' 14 and R' 16 is provided. Similarly, there are two resistors R between m anti-FI$2 and comparator C2.
A voltage dividing circuit consisting of 13 and 815 is provided and the Z.0 circuit 4
The operation of 5 is as follows.

First, it is assumed that signal FA is at logic level 1 and signal B''B is at logic level 0. Therefore, transistors 51 and 5
2 is in a conductive state, and transistors 50 and 53 are in a non-conductive state. Therefore, current flows from the positive electrode to the ground through the transistors 51 and 52 and the detection resistor E (SL') in the winding B.
It flows through Bi. Due to this current increase, the detection resistor R3
The voltage on I rises, and eventually the comparator 61, which continuously compares this voltage with the reference voltage 4.12, is activated. When the conhalator G1 and TJ'dJ are activated, the flip-flop 48 is inverted and the level of the inhibition signal NI becomes O, so that the power supply is disconnected from the windings B and B. When the signal I N l is at level 0, a new pulse O8 is output from the oscillator 60 (see Fig. 4) (see Fig. 8).
Continue with -1. When the signal INI becomes level 1, the initial power supply state is restored.

The above motion continues while the signal FA maintains level 1. A similar operation is performed for the circuit portion where the windings A and A are connected from the FC and FD VC.

As is clear, the frequencies of the signals FA, FB, FC and F' D generated by the Tecourg rotation WJ46 can be varied according to the angular distance 1 to 1 which the rotor must advance in order to reach the desired position. This is a well-known technique and can be achieved by a program recorded in the memory of the control unit 1-13.Although the time required to cover all the coils L over this angular distance can be shortened, the public force increases, so the rotor stops at the desired position.

As a result, the point at which one element in the fracture direction can be used is delayed because it vibrates around it.

Now that we have finished explaining the general voltage detection matters, we will now move on to the control circuit 10 (see Figure 1) according to the present invention, that is, the circuit that can damp the vibrations of the rotor after it has moved to a desired angular position. Explain in detail.

In accordance with the present invention, a brake circuit 14 is coupled to the O. of the windings of the stepper motor 11 to detect all electrical signals representative of the speed of the rotor. This information is processed and used to vary the power delivery to other windings, as detailed below.

To better understand this feature of the invention, - by way of example, FIG. 5 shows a step motor similar to that of FIG. The ends 70 and 71 are connected to two three-position switches 72.
-91 winding B has 2
It is connected to two switches 74 and 75, and the winding 76 is not connected to the power supply VAK, and one end 76 is connected to ground, and the other end 76 is connected to the ground.
7 is connected to the braking circuit.

Therefore, although the motor 11 appears to be a unipolar motor, it actually constitutes a bipolar motor depending on the winding connection method.

The braking circuit 14 (see FIG. 6) consists of four blocks 80.8.
1.82 and 83. Blocks 80 and 83 constitute a filter and gain adjustment means, block 81 is a simple inverting section, and block 82 is a logic section that handles the signal A T T 3 from the control unit 13 and the signal PO8 from the decoder circuit 46. It is. Specifically, the block 80 has an amplifier 85 whose first power is -1, volume 1'AIB
A voltage signal proportional to the back emf ()3ack EMF) of
(given through r. The second power of amplifier 85 is resistor R
= grounded via l. A comparator 012 and a resistor R1 are inserted between the output of the amplifier 85 and the first human power.

Block 80 (also includes resistor T (12 and capacitor C)
Has r3*.

The Zoroku 81 has an amplifier 86, the first input of which is connected to the output of the Noroku 80 via a resistor 6;
The second human power is grounded through a resistor 1 (7'c). A resistor R5 is provided between the output of the amplifier 86 and the first human power.

The logic section 82 has two NAND gates 87 and 88,
The human power on one side of each gate is the control cornisoto 13 (η1,1
(see figure). Game 1・
The other input of 87 (see FIG. 6) is the decoder circuit 46.
(See FIG. 7), and the other input of gate 1.88 is connected via an inverter 89 to signal PO3K. The logic section 82 (d) further comprises two field effect transistors (1('ET) 90 and 91, the control electrodes of which are connected to the outputs of the gates 87 and 88, respectively. is resistance R9
'x connected to the output of block 80 J, -9,
The input of F″ET T91 is connected to the control circuit 81 via resistor R8.
0 outs are connected.

Flock 83 has two resistors 1l-(8, R9 and amplifier 9
:3woi1, the first power of the amplifier is D″ET90 and 91
, and the second human power is grounded via a resistor R11. A capacitor G1.4 and a resistor R10 are connected between the output of the amplifier 93 and the first power source. Braking time: The output SMR of the flame 14 is controlled by the control circuit 12 (Fig. 1,
(see Figure 7).

Control circuit 12 is similar to circuit 45 (FIG. 4) described above in that it can control a bipolar stenomorph. The difference between the two is that in circuit 12, the detection resistor R82 and the associated resistor R13
One end is connected to the output of the braking circuit 14. Therefore, the circuit 14 reproduces the back emf present in the winding B of the motor 11 and extracts the speed 4'Ff signal from it, thereby increasing the winding The electric currents in lines A and A are fully modulated to achieve the desired damping effect.

Winding B (in exceptional cases, the rotor is rotated all the time, but u:
Components other than the back emf RTT force signal that should not be isolated are also induced in the winding (which does not use the RTT signal). Therefore, the point to be considered is that after issuing the final step command to the motor (after braking motor 1), the current flowing through winding B will no longer change; The component is winding B ((
This means that it will cease to exist. That is, the braking motor consists of only two components, one being the frequency of the pulse O8 (22K[-1Z
) is the square wave component, and the other is the back electromotive force.

If there is a square wave component 0:j-1, as mentioned above,
Current passing through glands A-A and VC
Therefore, by opening and closing the power supply means of u['' and others at the frequency of the pulse OS, ξ control is performed.

This 22 kHz frequency component (at both ends of winding B) has a peak-to-peak magnitude that is almost the same as the power supply voltage VA (FIG. 9).

The block 80 (FIG. 6) of the brake circuit 14 consists of circuit elements (
R2, R3, C1l), (R1, C:12) and (E
(J2.C13) filter the signal 22KH7 component of the winding B, and the amplifier 85 amplifies the counter-motive force component. Output signal S of block 80
Waveform f of X: Shown in FIG. As you can see from this diagram,
The signal SX is proportional (albeit inverted) to the signal amplitude representing the full effective angular velocity of the motor shaft relative to the nominal rest position, and also has some residual component of 22 Kt(z).

Each filter reduces the 22K H7 component to about 1, so that at the output of block 80 the magnitude of this component is approximately equal to the product of the supply voltage VA and the gain factor of amplifier 85. 4°O(l VC.

θ(, the vibration of the rotor 20 at the end of the nominal stop position, W
We will now explain how to use a signal representing the angular velocity of the rotor to brake l.

First, the windings A, A and Bi are both energized and the rotor 20 is stopped at a position where its N pole is between the magnetic pieces 16 and 17 (as shown in FIG. 5).

In the signal (Fig. 9), when the rotor is moving toward the magnetic pole piece 16, the positive direction is positive;
When it is moving towards , it is considered a negative direction.

Winding B is wound around the magnetic pole pieces 17 and 19 so that it has a positive voltage when the rotor is moving towards pole piece 16 and a negative voltage when it is moving towards pole piece J7. This induced signal in winding B is supplied to circuit 14, filtered and amplified, and used to modulate the currents A and A flowing in windings H4yA and H8.

In detail I11, 'Tunryucho 71. π becomes as shown in FIG.

This figure 1) As you can see, the current air, the person is the rotor 20
When it goes towards the sky, it gets bigger,
■When the coater moves toward the iwaboha 16, it becomes smaller.

However, when the N pole of the o-torter 20 is stopped between the magnetic pole pieces J6 and 17, the current in the windings A, A and B is To damp the vibrations of the rotor 20 in this position, the modulation of the current in the windings A and A must also be reversed.To achieve all this, the signal relating to the position of the rotor 20 pos
(created by decoder circuit 46). Signal P
o5il'':i: The N pole of the rotor 20 is the magnetic pole piece 16 or 17
When it is between the pole pieces 18 and 19, the logic level is 1.
The Jg match in between becomes level O.

Now, when the control unit 13 issues the last step command to be executed to the circuit 12, it also sets the logic level of the signal ATT to 1 to narrow the brake circuit 14. Braking circuit 1
4 is normally deactivated since signal ATT is at logic level O.

Belief A '1' When the logic level of T is 1 (6th
), when signal PO8 is at logic level 1, FET9
When Q is closed, p″ET91 is open, and when signal PO8 is at logic level O, FET90 is open and FET91 is closed.

Therefore, when the rotor 20 is stopped at the position shown in FIG. 5, the signal SX outputted from the block 80 (see FIG. 6) is supplied to the amplifier 93 of the block 83 via the resistor R9f. Therefore, the output signal S of circuit 14
Ivi R is the completely inverted and amplified signal SX (
(See Figure 9).

However, when the coater 20 (see FIG. 5) is stopped at a position where its N pole is halfway between the magnetic pole pieces 18 and 19,
The output signal of the block 80 (see FIG. 6) is sent to the amplifier 93 of the block 83 via the SX gate lock 8J and the resistor R8. Since the block 81 is just an inverting amplifier with unity gain, the signal Sx is once inverted in the block 8J,
The precision is reversed by the clock 83, so that the output signal SMFf of the circuit 14 is the same phase as Sx, although it is an amplified version of Sx.

In any case, capacitor C14id22 KHZ
Acts as a filter to further remove components. As mentioned above, the signal SMI' is thus sent to the open side j circuit 12 (see FIG. 7).

Does it flow to windings A and A? W 7A lower 8. The instantaneous value of A is equal to (RJ-30) (15) and the instantaneous value of the ratio VCVS2 of R13 (multiplied by the ratio of direct and R82).The voltage Vs2 will always be the reference value VR1,9. However,
For current, the peak of τ can be seen as equal to the ratio of (R13+R15) and RI3 multiplied by the ratio of VI('TEF and R82).

When the signal $1φR is zero, the current flowing through the windings A and A becomes the nominal current In. However, when the signal SMR is positive or (r) takes a negative value, d:, winding current air, 7,
k l<>, decreases or increases (d), modulating the current with respect to n below the nominal value. The reason for this is that the voltage of resistor R82 plus the voltage of qs MH becomes ■S2 and therefore ■
Hl! This is because it must be maintained equal to :l'i.

As a result, the rotor 20 is rapidly braked.

As is clear from the above explanation, the braking circuit is connected to one of the windings of the motor, and from that winding all signals representing the angular velocity of the rotor are output, and from this signal the acid force is applied to the other windings. By adjusting the supply voltage 416, it is possible to damp the vibration of the rotor when stopping the rotor at a desired angular position. - Embodiments other than those described above are also possible.

The use of the circuit according to the invention as a control circuit for a stepper motor for the angular positioning of a character wheel in an office printer has produced remarkable results. That is, by suppressing the vibration of the rotor, the total time of each selection cycle can be shortened to half Fr, and the speed of the printer can be significantly increased.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a control circuit embodying the present invention, Fig. 2 is a schematic diagram of a single-pole step motor, and Fig. 3 (
f, j Schematic diagram of bipolar step motor, 884 diagram &:
I: Circuit diagram of a control circuit of a bipolar step motor, Fig. 5 is a circuit diagram of a circuit according to the present invention vC up-controlling blue-colored step motor - 4 times, Fig. 6: i A circuit diagram implementing the present invention. Detailed circuit diagram of Maki 1 part. Figure 7 is a detailed circuit diagram of the second part of the above implementation circuit, Figure 8 is a waveform diagram of some signals of the circuits shown in Figures 4 and 7, Figure 9 is the diagram of the circuit shown in Figure 6. The waveforms of some signals in the circuit of
It is. It, Uma'ImM'1 person Ink Chii Olivenochi
And Chii0 Nis Hi0-A (5 others)

Claims (1)

[Scope of Claims] (1) A circuit for controlling a step motor having a rotor (2fl) and a plurality of windings (A, A, B, B) selectively comprising: In a circuit having a power supply (12)' connected to the winding for rotating the rotor towards a desired angular position, the braking circuit (14)
When the signal representing the angular velocity of the rotor (20) is connected to one of the windings (B) and all the signals representing the angular velocity of the rotor (20) are output, the 'power supply device (
12) to change the power supply to other windings so that the vibrations of the rotor that occur when the rotor is stopped at the desired angular displacement 16- are damped. circuit. (2. In the circuit described in claim 1, the winding of the step motor is divided into four phases (A, A, B, B), and three of these phases (A, A, B) are Connected to a power supply (I2), this device (121) is selectively biased +j to rotate the rotor (20) towards the desired angular position, while the fourth phase is braked. circuit(
14) A circuit characterized in that it is connected to. (3) In the circuit according to claim 2, two phases (A, A
) is a circuit characterized in that the motors are connected in antiparallel to each other so as to form a bipolar configuration. (/I) 71 In the circuit set forth in claim 3, fli! l motion circuit +14) l=, J, rotor (2
0) vibrates at the desired angular position.
A) A circuit characterized in that it provides a detection resistor (f(J:3)K) associated with the circuit.
, i to t in the fourth term, the fixed pole pieces (16 ( 9) between the two pole pieces, and a nominal current is supplied to the three phases connected to the power supply (12) in order to stop the rotor at this desired angular position. (6) In the circuit according to claim 4 or 5, the braking circuit (14) has an anti-parallel connection.
The currents in the windings (A, A) of the two phases are [co-ta (20)
A circuit characterized in that the desired angular position of the oscillator is changed in proportion to the vibration speed IW. (7) In the circuit according to claim 1, the power supply device (I2) selectively selects the windings (A, A, B, B) based on data supplied from the control unit (13). energizing and braking circuit (1<)+J, while the rotor is rotating towards the desired angular position iqJ, is deenergized by the control unit, causing the rotor to rotate towards the desired angular position. A circuit characterized by being the old capital when the final step is executed. (8) In the circuit according to claim 1, power is supplied to the windings and motors (A, A, B, B) of the motor with a modulation motor 1' of a predetermined frequency, and 0 and braking. A circuit characterized in that the circuit (14) comprises at least one demodulation circuit (80) k for demodulating an electrical signal representative of the angular velocity of the rotor.