RU2784828C1 - Apparatus for programmable control of a stepper motor - Google Patents

Abstract

FIELD: controlling.

SUBSTANCE: invention relates to the field of automation and computing technology, and can be used to automate the control of displacement mechanisms in units equipped with stepper electric drives. The technical result of the claimed technical solution is achieved by including interrelated logic elements "AND", "OR", dividers by 2, a clock frequency generator, a reset pulse shaper, pulse counters, a code comparison circuit, triggers, a displacement sensor, and a shift register.

EFFECT: ensured fault-free operation of the apparatus.

5 cl, 1 dwg

Description

The invention relates to automation and computer technology and can be used to automate the control of movement mechanisms in crystal growth installations, metal-cutting machines and other devices equipped with stepper electric drives.

A stepper motor control device [1] is known, containing a stepper motor, a stepper motor position indicator, a comparison element, a controlled signal source, a winding switch, a speed controller, a controlled delay unit, an adder and a code converter.

However, this device uses a code indicator of the positions of a stepper motor, which significantly limits the use of this circuit design due to the high cost of the code position indicator. In addition, to control the stepper motor in this device, it is necessary to change two physical parameters: the speed signal from the master in the controlled signal source and the controlled delay signal in the speed controller, which complicates the process of controlling the stepper motor.

A device for program control of a stepper motor [2] is also known, containing a program input unit, a pulse shaper of the installation, a phase switch, an "OR" element, a displacement sensor and a trigger. In this device, according to the program, the pulse comes from the output of the input block through the "OR" element to the first input of the switch and causes the rotation of the stepper motor, which is rigidly mechanically connected to the pulse-type displacement sensor. During normal operation, when there are no errors during movement, for each pulse of the program from the input block, a pulse must also come from the displacement sensor.

With a negative or positive error, when two pulses less or more than from the displacement sensor are received from the input block, the R-trigger performs the function of a frequency comparison circuit and switches the passage of pulses from the input block to the first one that allows the switch input, thereby eliminating the positive error .

This device does not provide reliable control and control of the acceleration speed of the stepper motor. So, for example, if from the input of the program stepwise, from zero, the maximum frequency of controlling the stepper motor is applied, then this circuit will not be able to work out the specified signal.

However, the most important disadvantage of both devices listed above is the possibility of stopping the stepper drive with an increase in the load on the movement mechanism due to an emergency situation, for example: "mashing" in some units of installations, such as crystal growing installations, poor lubrication in the gearbox of the movement mechanism, and others. factors.

The torque on the shaft of stepper motors has a significant dependence on the speed of rotation of the motor shaft. The ratio of torques at low speeds (motor control frequency within hundreds of hertz) to torques at high speeds (motor control frequency within units of kilohertz) is 5, 6 or more times.

The technical objective of the invention is to improve the reliability of stepper motor control and provide a given operating speed in emergency situations. The proposed device, with an abnormal increase in the load on the stepper motor, leading to its stop, automatically switches the control device to a low control frequency, thereby increasing the torque of the stepper motor several times. Having overcome an abnormal increase in load, the device automatically accelerates the stepper drive to the set operating speed of rotation (up to the set stepper motor control frequency).

The technical result is to ensure the normal trouble-free operation of the installation in which the proposed device is used.

The solution of the set technical problem and the achievement of the desired result are ensured by the fact that in the device for program control of a stepper motor, containing a program input unit (1), an installation pulse shaper (2), a phase switch (23), an "OR" element (15), a sensor displacements (21) and a trigger (16), additionally introduced two frequency dividers by two (4 and 5), a clock frequency generator (3), two reset pulse shapers (6, 9), six “AND” blocks (7, 8, 10, 18, 19, 20), two pulse counters (AND, 13), a code comparison circuit (12), a second "OR" element (12), a shift register (14) and a second flip-flop (17). At the same time, the output of the program input block (1) is connected to the first frequency divider by two (4), the fourth and fifth elements "AND" (18, 19), the pulse shaper (2) is connected to the first and second frequency divider by two (4, 5), as well as to the first element "OR" (15), the clock frequency generator (3) is connected to the first and second element "AND" (7, 8), the first frequency divider by two (4) is connected to the first element "AND" (7), the third "AND" element (10) and the first reset pulse shaper (6), the second frequency divider by two (5) is connected to the second and third "AND" elements (8, 10), as well as to the second pulse shaper reset (9), the first reset pulse shaper (2) is connected to the first pulse counter (11) and the shift register (14), the first element "AND" (7) is connected to the pulse counter (11), the second element "AND" (8 ) is connected to the second pulse counter (13), the second reset pulse shaper (9) is connected to the second pulse counter (13), the third "AND" element (10) is connected to the second trigger (17), the first pulse counter (11) is connected to the code comparison circuit (12) and the first "OR" element (15), the second pulse counter (13) is connected to the code comparison circuit (12), and the latter is connected to the second trigger (17), the shift register (14) is connected to the first flip-flop (16) and the first "OR" element (15), the first flip-flop (16) is connected to the fourth "AND" element (18), the fifth "AND" element (19) and the sixth element "AND" (20), the second trigger (17) is connected to the fifth element "AND" (19) and the sixth element "AND" (20), the fourth element "AND" (18) is connected to the second element "OR" ( 22), the fifth element "AND" (19) is connected to the second element "OR" (22), the sixth element "AND" (20) is connected to the second element "OR" (22), the second element "OR" (22) is connected to the switch phase switch (23), the phase switch (23) is connected to the stepper motor (24), which is electrically connected to the displacement sensor (21), which is connected to the sixth element "AND" (20) and the second voltage divider by two (5).

A 4-bit binary reversible counter - a K555IE7 microcircuit was used as a frequency divider, and a KR1006VI1 microcircuit was used as a generator. A 4-bit digital comparator-microcircuit K555SP1 was used as a comparison circuit. As each of the triggers, a D-trigger is used, the function of which is performed by the K555TM2 microcircuit.

The essence of the invention is illustrated by the diagram in the figure, where:

1 - program input block;

2 - pulse shaper;

3 - clock frequency generator;

4 - the first frequency divider by two;

5 - second frequency divider by two;

6 - the first reset pulse shaper;

7 - the first element "And";

8 - the second element "AND"

9 - second reset pulse shaper;

10 - the third element "And";

11 - the first pulse counter;

12 - code comparison scheme;

13 - second pulse counter;

14 shift register;

15 - the first element "OR";

16 - first trigger;

17 - second trigger;

18 - the fourth element "And";

19 - the fifth element "And";

20 - the sixth element "And";

21 - displacement sensor;

22 - the second element "OR";

23 - phase switch;

24 - stepper motor;

ft - clock frequency;

fpr - frequency of pickup of a stepper motor;

fz - frequency of rotation of the motor shaft set by the operator;

fd - the actual speed of the motor shaft measured by the sensor.

The device works as follows.

When the power is turned on, the initial setting pulse shaper 2 generates a single setting pulse, which sets the frequency dividers 4, 5 by two, the shift register 14 and the trigger 16 in the initial state, i.e. direct outputs of frequency dividers 4, 5 by two are set to position "1", shift register 14 is set to position "0" at the inverted output, trigger 16 is set to position "1" at direct output.

Thus, at the initial moment, the "AND" circuits 7, 8 are open for the passage of electrical pulses with a frequency ft from the clock frequency generator 3 through them. The "AND" elements 19, 20 are closed by the low potential of the trigger 16, and the "AND" element 18 is open and allows the signal fz to pass through the "OR" elements 22 to the phase switch 23 and then to the stepper motor 24.

The frequency ft coming from the clock frequency generator 3 is selected in such a way that when the signal period fc is filled with the frequency ft in the case of 0≤fc≤fpr (where: fpr is the pickup frequency of the stepper motor), the pulse counter 11 is completely filled, i.e. . with the "highest digit" inclusive, and when fz>fpr - filling the pulse counter 11 until the "highest digit" is triggered.

The reset pulse shaper 6 is used to reset the pulse counter 11 to "0" before each cycle of measuring the frequency period fc, and the reset pulse shaper 9 is used to reset the pulse counter 13 to "0" before each measurement cycle of the frequency period fd.

The device has three modes of operation:

- the first mode - at 0≤fз≤fpr

- the second mode - at fpr<fз≤fд

- the third mode - when fz>fd.

In the first mode of operation, the flip-flop 16 is constantly set to position "1" at the direct output by the "high order" signal (coming from the counter 11 and passing through the "OR" element 15 to the R-input of the D-flip-flop 16). In this case, the passage of the signal fz through the element "AND" 18 is allowed and the passage of fz through the element "AND" 19 and the signal fd through the element "AND" 20 is prohibited.

The signal fz, passing through the "AND" element 18, the "OR" element 22, is fed to the phase switch 23, which drives the stepper motor 24.

The shift register 14 (in the first mode of operation) serves to prohibit the passage of reset pulses coming from the pulse shaper 6 to the trigger 16. This is achieved by the fact that the shift register 14 is a two-bit shift register and each incoming pulse from the shaper 6 and entering the shift register input 14 sets the first bit of the shift register 14 to the "1" state, and the "most significant bit" signal generated in the pulse counter 11, passing through the "OR" element 15, resets the shift register to "0", i.e. reset pulses from the shaper 6 cannot pass through the shift register 14 and flip the flip-flop to another state.

In the second mode, the counter 11 from the element "And" 7 receives bursts of pulses with a frequency ft, the duration of the burst is equal to the period of the frequency fz.

The pulses are counted in the counter 11, and then the number of counted pulses is converted into a parallel code that enters the comparison circuit 12. Similarly, the counter 13 receives bursts of pulses with a frequency ft, and the duration of the burst is equal to the period of the frequency ft. Parallel codes from counters 11 and 13 are compared in the code comparison circuit 12 and the result of the comparison is fed to trigger 17. The signal "1" is set at the direct output of trigger 17 and allows the signal fc to pass through the element "AND" 19.

The trigger 16 also allows the signal fz to pass through the "AND" element 19, since in the second mode of operation the "high order" signal does not work, and the reset pulses from the pulse shaper circuit 6 transferred the trigger 16 to the "1" state at its inverse output. The signals fz, passing through the element "AND" 19, the element "OR" 22, are fed to the phase switch 23, and the latter sets the stepper motor 24 in motion.

In the third mode of operation, the so-called "self-generation" mode, the signals coming from the displacement sensor 21 pass through the frequency divider 5 by two and from its direct output go to the "AND" element 8, where bursts of pulses with a frequency ft are formed, and the duration of the pulse burst equal to the frequency period fd.

These pulses are counted in the pulse counter 13. The code comparison circuit 12 receives parallel codes for the number of counted pulses in each pack from the counters 11, 13. The result of the comparison from the code comparison circuit 12 is fed to the first input of the trigger 17. The second input of the trigger 17 and the input element "AND" 10 receives signals that allow you to receive a signal for comparing codes from the comparison circuit 12.

Thus, in the third mode of operation, the trigger 17 is transferred to the "1" state at the inverse output and allows the signal to pass through the "AND" element 20, the "OR" element 22 and then to the phase switch 23 and the stepper motor 24. In this case, the rotation speed stepper motor 24 is determined by the parameters of the motor itself and its load, and under the influence of positive feedback, it accelerates to the value fz and switches to the second mode of operation or, if f3 is very high, then to the value of the maximum possible rotation speed of this stepper motor.

This control circuit is highly resistant to failure of the stepper motor control, since with any jump in the frequency fc, the control circuit is switched to the auto-generation mode, and then from the auto-generation mode it automatically switches to the first or second operating mode.

The use of the auto-generation mode allows you to minimize the acceleration and deceleration time of the stepper motor, since this mode provides the best option for automatic tuning depending on changing external conditions.

The invention was successfully applied in a stepper electric drive with a "DTTTI 200-3" motor in the "Sapphire-2M" crystallization plant at the Federal Research Center "Crystallography and Photonics" of the Russian Academy of Sciences, which indicates its industrial applicability.

Sources of information

[one]. USSR author's certificate No. 962858, "Stepper motor control device", IPC G05B 19/40, publ. 09/30/1980

[2]. USSR author's certificate No. 1399704, "Device for program control of a stepper drive", IPC G05B 19/40, publ. 05/30/1980 (prototype).

Claims (5)

1. A device for program control of a stepper motor, containing a program input unit (1), an installation pulse shaper (2), a phase switch (23), an "OR" element (15), a displacement sensor (21) and a trigger (16), different by the fact that two frequency dividers by two (4 and 5), a clock frequency generator (3), two reset pulse shapers (6, 9), six “AND” blocks (7, 8, 10, 18, 19 , 20), two pulse counters (11, 13), a code comparison circuit (12), the second “OR” element (12), a shift register (14) and a second trigger (17), while the output of the program input block (1) connected to the first frequency divider by two (4), the fourth and fifth elements "AND" (18, 19), the pulse shaper (2) is connected to the first and second frequency dividers by two (4, 5), as well as to the first element " OR "(15), the clock frequency generator (3) is connected to the first and second elements "AND" (7, 8), the first frequency divider by two (4) is connected to the first element "AND" (7), the third element "AND " (ten ) and the first reset pulse shaper (6), the second frequency divider by two (5) is connected to the second and third elements "AND" (8, 10), as well as to the second reset pulse shaper (9), the first reset pulse shaper (2 ) is connected to the first pulse counter (11) and the shift register (14), the first element "AND" (7) is connected to the pulse counter (11), the second element "AND" (8) is connected to the second pulse counter (13), the second the reset pulse shaper (9) is connected to the second pulse counter (13), the third "AND" element (10) is connected to the second trigger (17), the first pulse counter (11) is connected to the code comparison circuit (12) and the first "OR" element "(15), the second pulse counter (13) is connected to the code comparison circuit (12), and the latter is connected to the second trigger (17), the shift register (14) is connected to the first trigger (16) and the first "OR" element (15 ), the first trigger (16) is connected to the fourth element "AND" (18), the fifth element "AND" (19) and the sixth element "AND" (20), the second trigger (17) is connected to the fifth element "AND" (19) and the sixth element "AND" (20), the fourth element "AND" (18) is connected to the second element "OR" (22), the fifth element "AND" ( 19) is connected to the second element "OR" (22), the sixth element "AND" (20) is connected to the second element "OR" (22), the second element "OR" (22) is connected to the phase switch (23), the phase switch (23) is connected to a stepper motor (24), which is electrically connected to a displacement sensor (21), which is connected to the sixth element "AND" (20) and the second voltage divider by two (5). 2. The device according to claim 1, characterized in that a 4-bit binary reversible counter is used as a frequency divider - a K555IE7 microcircuit. 3. The device according to claim 1, characterized in that a 4-bit digital comparator-microcircuit K555SP1 is used as a comparison circuit. 4. The device according to claim 1, characterized in that the KR1006VI1 chip is used as a generator. 5. The device according to claim 1, characterized in that a D-trigger is used as each of the triggers, the function of which is performed by the K555TM2 chip.

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