JPS63107497A - Controller for stepping motor - Google Patents

Abstract

PURPOSE:To prevent a resonance phenomenon from occurring in a stepping motor thereby to improve a stepout limit by varying the frequencies of a plurality of pulse trains having the same frequency at each predetermined time. CONSTITUTION:Pulse train data generated by pulse train generating means 2 at the time of slow-up, pulse train data at the time of constant speed operation, and pulse train data at the time of slow-down operation are stored in memory spaces designated by addressing means 3 according to a speed pattern by pulse train memory means 4. When a stepping motor 8 is driven, the pulse train data are read out, and fed to pulse output means 6. At this time, the frequencies of a plurality of pulse trains having the same frequency are varied at each predetermined time.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a control device for a stepping motor, and more particularly to a control device that controls the frequency of input pulses to prevent resonance phenomena and improve the step-out limit. be.

[Prior art] Generally, when driving a stepping motor at high speed, the sixth
As shown in the figure, it is first started at a frequency (fl) within the self-starting region of the speed-torque characteristic. Thereafter, in order to prevent the rotor from misstepping, the pulse frequency is linearly and continuously slowed down from (fl) to (f2) when entering the acceleration operation range. Then the pulse frequency reaches (f2),
When entering the deceleration operation range where the pulse frequency is lowered from (f2) to (fl) after a certain period of time, similarly to the above acceleration operation,
The pulse frequency is linearly and continuously slowed down from (f2) to (f+). As a result, acceleration and deceleration of the stepping motor can be controlled in accordance with the drive pattern.

A typical control device for this is shown in Fig. 7. In Fig. 7, (1) shows a drive pulse for driving the stepping motor and a direction pulse for commanding the rotation direction based on an external rotation command. A control circuit (la) controls the output by a microcomputer (hereinafter abbreviated as microcomputer), and (7) is a stepping motor drive circuit that inputs a drive control output to the stepping motor (8) based on each of the above-mentioned pulses. The load is driven under the drive control of (8).

Conventionally, as a method for generating pulse signals according to the driving pattern of the stepping motor (8) as described above, each bit information constituting the pulse train for each pulse pattern is stored in individual memory addresses, and There is a method of storing each pulse pattern in each space and then accessing the memory and outputting the pulse data.

However, as a method for generating pulse patterns during slow-up and slow-down of a stepping motor,
Conventionally, a memory table is provided in which logical "l" information and logical "O" information are successively stored in each memory address at regular intervals, and as shown in FIG. 8, "l" information is stored in this memory table. Each interval between each address memory is continuously reduced to generate a memory table at the time of slow-up. In addition, as a memory table during slowdown, a memory table is generated by continuously expanding each interval between each address memory where °゛1'' information is stored.Then, this generated memory table is used by the microcontroller ( 1a
), the stepping motor (8)
During slow-up operation, the memory area in which slow-up information is stored is sequentially accessed at regular time intervals. As a result, the control unit (1) sends a pulse train having each pulse period determined by each memory address interval and memory access time to the stepping motor drive circuit (7).
Output to. During slowdown operation, the memory area in which slowdown information is stored is accessed using the memory access method described above, and a pulse train in which each pulse cycle is continuously expanded and changed is output to the stepping motor drive circuit (7). As a result, the rotational speed of the stepping motor (8) increases as the pulse frequency increases and decreases as the pulse frequency decreases.

[Problems to be Solved by the Invention] Conventional stepping motor control devices continuously increase the pulse frequency up to a certain frequency range when the input pulse speed is slowed up or down during acceleration and deceleration operation of the stepping motor. After a certain period of time, it was continuously decreased from the constant pulse frequency range to a certain frequency range, so in a certain frequency range, the tax adjustment limit was lowered due to the resonance phenomenon that occurred due to the coincidence with the natural frequency of the rotating system. ,
This poses a problem in that the stepping motor may become unstable or rotate in reverse.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a stepping motor control device that suppresses the resonance phenomenon caused by a specific pulse frequency and improves the step-out limit.

[Means for Solving the Problems] According to the stepping motor control device according to the present invention, a plurality of pulse train data having different pulse frequencies are stored in a memory space in the order of increasing pulse frequency, and
A plurality of pulse train data are stored in a memory space in the order of decreasing pulse frequency to generate a memory table in which pulse train information is stored when the pulse speed is slowed up and slowed down, and from this memory table when the pulse speed is slowed up and slowed down. The device is equipped with means for sequentially reading pulse train data and outputting a pulse signal whose frequency increases or decreases in a stepwise manner to a drive circuit.

[Operation] According to the stepping motor control device according to the present invention,
During slow-up or slow-down operation of the stepping motor, the pulse frequency is increased or decreased in steps to control the pulse speed while driving the stepping motor at high speed. The resonant vibration caused by a partial change in the pulse train frequency at the time decreases while the pulse train signal of the same frequency is output, and the vibration can be suppressed.
Resonance regions can be avoided even during continuous variable motor speed operation by varying the pulse speed.

[Embodiment] FIG. 1 is a block diagram of an embodiment of a stepping motor control device according to the present invention.

The pulse train data for slow-up operation, the pulse train data for constant-speed operation, and the pulse train data for slow-down operation generated by the pulse train generation means (2) are stored in the memory space specified by the addressing means (3) according to the speed pattern. is stored by the pulse train storage means (4). When the stepping motor (8) is driven, the pulse train data is read from the leading address of the memory space where the pulse train data is stored and sent to the pulse output means (8). In order to sequentially read pulse train data from each memory address in the memory space, the address designation means (3) is
Every time one pulse train data is read out from the pulse train storage means (4), an address increment signal is sent out from the pulse train data reading means (5).

FIG. 2 is a system configuration diagram of the stepping motor used in the above embodiment. In the figure, (9) is a coupling, which connects the mechanical system and the stepping motor (8).

and (lO) is the load engaged on the mechanical system. still,
Since the other parts are the same as those in FIG. 7, detailed explanation will be omitted.

Next, the operation of the above embodiment is shown in FIGS. 3 and 4(a).

(b) will be explained with reference to FIG.

FIG. 3 is a waveform diagram of the drive pulse sent from the control circuit (1) to the stepping motor drive circuit (7) in this embodiment, and a pattern diagram of the pulse frequency according to the motor drive pattern. As shown in this figure, the frequency change during slow-up from the frequency (fl) in the self-starting region to the frequency (fl) in the constant speed region changes from multiple pulse signals of the same frequency (fl) for a certain period of time. After outputting the configured pulse train, a pulse train with the frequency increased to (f3) is output for a certain period of time, and finally a pulse train with a frequency (fl) higher than (f3) is output until the time of slowdown. Furthermore, during slowdown, the frequency of the pulse train is decreased each time a pulse train is output for a certain period of time, and thereby the pulse frequency during slow-up and slowdown changes in a stepwise manner.

The above pulse train generation operation that changes stepwise during slow-up and slow-down will be explained with reference to the pulse output program flowchart shown in FIG. 4(a) and the pulse pattern storage memory table shown in FIG. 5. .

The pulse output calculation section of the microcomputer (1a)
and read rotation commands such as rotation direction commands (4-1)
, Next, the pulse pattern is determined based on these rotation commands, and the memory table (in which the pulse pattern is stored) is
(see Figure 5), calculates the first address (TA), determines the rotation direction, and outputs a direction pulse to the stepping motor drive circuit (7) (4-2) to (4-4)
. After determining the start address (TA++) above, the address (
Temporarily move the contents of TAz + ) to accumulator Ace in the microcomputer (la) for data transfer operation (4
-5). The microcomputer (1h) detects the data content of the accumulator AGO and determines whether it is "80" indicating the final data (4-13), and if it is "80", stops the pulse output. Also, if it is not '80'', °゛1''
4-7), and if it is “1”, it is determined as shown in Fig. 4 (b
) Turn on the rising pulse as shown in (4-8)
. Then, after a time T11 has elapsed during which the pulse width is determined, the pulse output is turned off (4-9) to (4-10). After turning off the pulse output, increment the memory address by one and update the read address (4-11);
The microcomputer (1a) side determines the contents of the update address (TAz, +), and if it is not 80°. (TALl・1)
Determine whether ≠1 (4J), (4-7),
As a result of this determination, if (TAu, +)≠1, the pulse output is turned off (4-12), and if Tw time has elapsed after the pulse output is turned off, the memory address is changed to (TAll
, 2) (4-12).

(4-13), (4-11). Then, the contents of the memory address (TAn) updated every rw time are (T, A n
)≠1, the pulse output is turned off (4-1
2). Then, if (TAn)=1, step (4-7
), repeat steps (4-8) to (4-1).
0), a pulse with a pulse width T is output.

A method for generating step pulse output will be explained in detail based on the above pulse train output program. First, during slow-up operation, pulse output information "1" is read from the first address (TAz), and then the following memory address (
Pulse output OF from TAll, +) to (TAll-4)
The following reading time (T = (T
11 (reading progress) + α (processing time)) x 4 (number of O")), the memory address (TAll, 5)
The pulse output information "1" is read out again. This generates a pulse train with a pulse period ((Tw + α) x 4). After a pulse train of 0 or more is generated, the memory address (TAll・6)～(TA
After the four pulse output OFF information is read from memory address (Tall, to), multiple pulse trains with the same pulse period are read out and the pulse signal is is output. Pulse output information “1” from memory address (A++, to)
” is read out, the two memory addresses ((TAL + 1
1) I(TAB・12)), ((TAll・+4)l(
The memory address (TAL
Pulse output information from l-13) and (TAll・16)
The pulse period ((Tw+α
)×2) multiple pulse trains are generated. By generating a pulse train in this manner, a pulse signal whose pulse frequency increases in a stepwise manner as shown in FIG. 3 can be sent to the stepping motor drive circuit (7).

In addition, when sending out a step pulse signal during slowdown, the memory address (TAll+2o) where pulse output information "1" is stored.

(TAll・23), (TAll・26), (Ding A1
1・31), (TAll・36) is set as the memory address ((TA
ll, 21), (TAll. 22), (TAll. 2
4).

(TAll・25), (TAll・27) ~ (TAll
・30), (TAll・32) to (TAth・35)) are expanded sequentially, and by sequentially accessing these memory addresses, a pulse signal whose pulse frequency decreases in a stepwise manner is sent to the stepping motor drive circuit (7). Can be sent.

[Effects of the Invention] As described above, according to the present invention, since the drive pulse generating means for changing the frequency of a plurality of pulse trains having the same frequency at regular time intervals and changing the pulse frequency in a stepwise manner is provided, The resonant vibration caused by the frequency change of the pulse signal of the pulse train is attenuated while other pulse trains are output, and the vibration can be suppressed. The present invention has the advantage that it can provide a control device for a stepping motor that is controlled by the controller.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of a stepping motor control device according to the present invention, FIG. 2 is a system configuration diagram of the stepping motor control device in this embodiment, and FIG. FIG. 4(a) is a flowchart showing the operation of the stepping motor control device according to the present embodiment; FIG. 4(b) is a pulse waveform diagram showing the form of the output pulse; FIG. 5 is a memory table storing step-like pulse train data, FIG. 6 is a pulse frequency pattern diagram during conventional slow-up or slow-down, and FIG. 7 is a system configuration diagram of a conventional stepping motor control device. FIG. 8 is a memory table in which conventional pulse train data at slow-up and slow-down times are stored. In the figure, (1) is a control circuit, (2) is a pulse train generation means, (3) is an addressing means, (4) is a pulse train storage means, (5) is a pulse train data reading means, and (6) is a pulse output means. , (7) is a stepping motor drive circuit, and (8) is a stepping motor. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A pulse signal of a predetermined frequency generated according to the operating state of the stepping motor is output from the pulse control circuit, and an excitation current output from the drive circuit based on the pulse signal is input to the stepping motor to control the motor drive. In a stepping motor control device, the frequency of each pulse train data output at fixed intervals is changed at a fixed rate, and each pulse train data is arranged in the order of increasing frequency to generate pulse train data during slow-up of the stepping motor. and pulse train data generation means for arranging each pulse train data in order of decreasing frequency to generate slowdown pulse train data for the stepping motor, and a pulse train for storing bit information constituting the generated pulse train data from each leading address, respectively. storage means; addressing means for specifying a read address for the pulse train storage means based on each rotation information; pulse train data reading means for outputting an address increment signal to the address designation means; The bit information sequentially read out from the means is outputted as a pulse,
A control device for a stepping motor, comprising: pulse output means for outputting pulses from the drive circuit.