JP7296620B2 - Drive controller for stepping motor - Google Patents

Description

The present invention relates to a drive control device for a stepping motor using closed-loop control, which operates the stepping motor in the same manner as a vector-controlled servomotor.

Conventional drive control devices for stepping motors include an open-loop control device that applies a pulse signal to perform desired rotation control, and a closed-loop control device that performs feedback control of the stepping motor rotation control using signals from an encoder. Devices are known for
A closed-loop control device has a configuration equivalent to a two-phase multi-pole AC servomotor with a position loop, velocity loop, and current control loop.・Other electronic devices).

JP 2016-63735

However, in a stepping motor drive device using closed-loop control such as that disclosed in Patent Document 1, hardware can be simplified by integrating many discrete components into a single chip and using a dedicated IC that incorporates excitation current waveform control. Although complicated control such as coordinate transformation and phase transformation is not necessary, there is a problem that four-quadrant operation required for servo operation cannot be performed.

SUMMARY OF THE INVENTION It is an object of the present invention to solve this problem and to provide an apparatus for driving a stepping motor in four-quadrant operation of closed-loop control using the aforementioned dedicated IC.

In order to achieve the above object, the stepping motor drive control apparatus according to the present invention comprises a stepping motor to be rotationally driven, position command means for commanding the rotational position of the stepping motor according to a control program, and control of the rotation of the stepping motor. drive means for supplying an exciting current to the stepping motor according to a signal from the rotation control means; and position detection means for detecting the rotational position of the stepping motor, wherein the rotation control means detects the position of the stepping motor. a position control section for outputting a rotation speed from the difference between a position command signal from the command means and a position detection signal from the position detection means; and a speed detection section for calculating the rotation speed from the rotation position of the stepping motor from the position detection means. a speed control unit for outputting a current setting signal from the difference between the rotation speed from the position control unit and the rotation speed from the speed detection unit; and a first pulse signal for advancing the stepping motor according to the position detection signal. and a second pulse command section for outputting a second pulse signal having a pulse width recognizable by the driving means based on the current setting signal and the position detection signal and a period shorter than that of the first pulse signal. and the second pulse command section advances the phase of the excitation current to a desired angle by the second pulse signal.

With such a configuration, the excitation current can be advanced by any angle.

Further, the stepping motor drive control device according to the present invention is configured such that the phase advance angle advanced by the second pulse signal can be set to 180 degrees.

With such a configuration, the stepping motor can be operated in four quadrants, enabling servo operation.

Further, the stepping motor drive control device according to the present invention is configured such that the phase advancing angle advanced by the second pulse signal can be set within a range of 0 degrees to 90 degrees.

With such a configuration, field-weakening control can be realized, and higher speed rotation can be obtained.

According to the stepping motor drive control device according to the present invention, the first pulse signal for driving the stepping motor is interrupted by the second pulse signal having a shorter period than the first pulse signal for arbitrarily advancing the phase. The excitation current can be set to any advance angle.
Further, by advancing the exciting current by 180 degrees, it is possible to realize four-quadrant operation control having operation modes of forward rotation power running, forward rotation regeneration, reverse rotation power running, and reverse rotation regeneration.
Furthermore, by advancing the excitation current by a desired phase amount of 0 to 90 degrees (for example, 22.5 degrees), field-weakening control can be realized, and higher-speed rotation can be obtained.
Further, by using a dedicated IC for the drive means of the stepping motor, four-quadrant operation can be realized with an inexpensive configuration.

1 is a schematic diagram showing a configuration example of a drive control device for a stepping motor according to an embodiment of the present invention; FIG. 2 is a diagram showing the configuration of rotation control means in FIG. 1; FIG. FIG. 4 is a waveform diagram showing a typical excitation current of a stepping motor; FIG. 4 is a waveform diagram showing an example of four-quadrant operation control in the stepping motor drive control device according to the embodiment of the present invention; FIG. 5 is a partially detailed waveform diagram of FIG. 4; FIG. 4 is a waveform diagram showing an example of field weakening control in the stepping motor drive control device according to the embodiment of the present invention; FIG. 7 is a partially detailed waveform diagram of FIG. 6;

A drive control device for a stepping motor according to the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing one configuration example of a stepping motor drive control apparatus according to an embodiment of the present invention. 1 is a stepping motor whose rotation is controlled, and 2 is a stepping motor rotation position command. 3 is a rotation control means for controlling the rotation of the stepping motor; 4 is a driving means for supplying an exciting current to the stepping motor according to a signal from the rotation control means; and 5 is for detecting the rotational position of the stepping motor. position detection means.

The stepping motor 1 comprises an A-phase stator, a B-phase stator, and a permanent magnet rotor, and is rotationally driven by an A-phase excitation current ECa and a B-phase excitation current ECb from a driving means 4 .

The position command means 2 consists of a control program 21 for the stepping motor 1 and a counter 22 .

The driving means 4 is a dedicated IC in which many discrete components are integrated into one chip and control of the excitation current waveform is incorporated.

The position detecting means 5 uses an encoder (not shown) positioned so that the magnetic flux generated by the A-phase excitation current ECa and the B-phase excitation current ECb and the magnetic flux of the permanent magnet rotor of the stepping motor 1 are orthogonal to each other, and detect stepping. It detects the rotational position of the motor 1 and outputs a position detection signal Pd.

FIG. 2 shows a configuration example of the rotation control means 3. As shown in FIG.
Reference numeral 31 denotes a position control section for outputting a rotational speed command signal Sc based on the difference between the position command signal Pc from the position command means 2 and the position detection signal Pd from the position detection means 5; A speed control unit that outputs a current setting signal Ic based on the difference between the speed command signal Sc and the rotation speed detection signal Sd from the speed detection unit 33 . A speed detection unit 34 calculates a speed and outputs a rotation speed detection signal Sd. 35 denotes a second pulse signal having a pulse width that can be recognized by the drive means 4 based on the position detection signal Pd from the position detection means 5 and the current setting signal Ic from the speed control part, and having a period shorter than the first pulse signal PLS1. This is the second pulse command section that outputs PLS2.

The position control unit 2 counts the pulse signal P1 and the rotation direction signal D1 output from the control program 21 of the stepping motor 1 by the counter 22, and outputs the position command signal Pc as a signal indicating the target value of the rotation position of the stepping motor 1. Output.

The position control unit 31 calculates the rotation speed from the difference between the position command signal Pc and the position detection signal Pd, and outputs the rotation speed command signal Sc as a signal indicating the target value of the rotation speed.

The speed control unit 32 calculates a current for exciting the stepping motor 1 from the difference between the rotation speed command signal Sc and the rotation speed detection signal Sd, and outputs a current setting signal Ic as a signal indicating the target value of the excitation current.

The speed detection unit 33 calculates the rotation speed from the position detection signal Pd and outputs the rotation speed detection signal Sd.

The first pulse command unit 34 outputs a first pulse signal PLS1 and a rotational direction signal DIR1 for advancing the stepping motor 1 according to the position detection signal Pd.
The second pulse command unit 35 outputs three types of signals, a second pulse signal PLS2, a rotation direction signal DIR2, and an excitation permission signal Ex, based on the current setting signal Ic and the position detection signal Pd.
The second pulse signal PLS2 is a signal having a pulse width that can be recognized by the driving means 3 and a period shorter than that of the first pulse signal PLS1.

The pulse signal PLS is a signal from which either the first pulse signal PLS1 or the second pulse signal PLS2 is output, and the rotation direction signal DIR is either the first rotation direction signal DIR1 or the second rotation direction signal DIR2. This is the output signal.
The first rotation direction signal DIR1 is output when the first pulse signal PLS1 is output, and the second rotation direction signal DIR2 is output when the second pulse signal PLS2 is output.

The driving means 4 is a dedicated IC for driving the stepping motor 1 with many discrete components integrated into one chip. An excitation current ECa and a B-phase excitation current ECb are supplied.

Next, the operation of one embodiment of the present invention will be described with reference to FIGS. 3 to 7. FIG.

FIG. 3 is a waveform chart when the stepping motor 1 is rotated forward by 1/8 microstep driving. 2 shows the time flow of the A-phase excitation current ECa and the B-phase excitation current ECb output from .

Next, a control method for switching the mode from normal rotation power running to normal rotation regeneration in four-quadrant operation according to the embodiment of the present invention will be described with reference to FIGS. 4 and 5. FIG.
As an example, in the excitation current waveform for 1/8 microstep drive in FIG. 3, when regeneration occurs at the timing indicated by C31, the excitation current waveform indicated by C33 is advanced by 180 degrees in order to reverse the polarity of the excitation current. need to switch to The result of switching is shown in FIGS. 4 and 5. FIG.
FIG. 5 is an enlarged view of the operation of advancing the excitation current by 180 degrees indicated by B41 in FIG.

At the timing indicated by T51 in FIG. 5, the excitation enable signal Ex of the drive means 4 is disabled to turn off the excitation current to the motor windings.
Next, while the rotation direction signal DIR of the stepping motor 1 maintains forward rotation (CW), as shown in S51 in FIG. 16 pulse signals) are applied to advance the angle.
Next, at the timing indicated by T52 in FIG. 5, the exciting current waveform is switched by turning on the exciting current to the motor windings by enabling the excitation enable signal Ex of the driving means 4 .

Incidentally, since the current command is generally zero when regeneration occurs, it is not essential to prohibit the excitation enable signal Ex while the second pulse signal PLS2 is being applied.

Next, a control method for switching the mode from forward rotation power running to reverse rotation power running in four-quadrant operation during 1/8 microstep driving will be described.
As in the control method for switching the mode from normal rotation power running to normal rotation regeneration, first, the excitation permission signal Ex of the driving means 4 is disabled to turn off the excitation current to the motor windings.
Next, while the rotation direction signal DIR of the stepping motor 1 maintains forward rotation (CW), the second pulse signal PLS2 is advanced by 180 degrees (in this case, 16 pulse signals) as the pulse signal PLS in a short cycle. applied to cause
Next, after changing the rotation direction signal DIR to reverse rotation (CCW), the excitation enable signal Ex of the driving means 4 is set to enable, and the excitation current waveform is switched by turning on the excitation current to the motor windings.

The rotation direction signal DIR of the stepping motor 1 is maintained until all the second pulse signals PLS2 are applied, and the rotation direction signal DIR is changed before the excitation permission signal Ex of the driving means 4 is permitted. The rotation direction signal DIR at that time is forward rotation (CW) in the case of forward power running/forward regeneration mode, and reverse rotation (CCW) in the case of reverse power running/reverse regeneration mode.

例として、１／８マイクロステップ駆動で励磁電流波形を１８０度進める場合、下式２となり

１６個の第２パルス信号ＰＬＳ２を駆動手段４に印加すればよい。 The number of second pulse signals PLS2 to be applied to the driving means 4 for switching the exciting current waveform is obtained by the following equation (1).

As an example, when advancing the excitation current waveform by 180 degrees with 1/8 microstep drive, the following formula 2 is obtained.

16 second pulse signals PLS2 may be applied to the driving means 4. FIG.

The table below shows the number of second pulse signals applied for mode switching of four-quadrant operation during 1/8 microstep driving.

Next, a method of controlling field weakening for high-speed rotation in an embodiment according to the present invention will be described with reference to FIGS. 6 and 7. FIG. In order to control the field weakening, the second pulse signal PLS2 for advancing the phase of the exciting current waveform is applied to the driving means 4 as the pulse signal PLS, thereby instantaneously switching the exciting current waveform.

As an example, in the excitation current waveform of 1/8 microstep drive in FIG. It is necessary to switch to the excitation current waveform shown by squared C32. 6 and 7 show the results of the switching.
FIG. 7 is an enlarged view of the operation of advancing the excitation current by 22.5 degrees indicated by B61 in FIG.

First, at the timing indicated by T71 in FIG. 7, the excitation enable signal Ex of the drive means 4 is disabled to turn off the excitation current to the motor windings.
Next, while the rotation direction signal DIR of the stepping motor 1 maintains the forward rotation (CW), the second pulse signal PLS2 is changed to the pulse signal PLS in a short cycle for 22.5 degrees (this two pulse signals) are applied to advance the angle.
Next, at the timing indicated by T72 in FIG. 7, the excitation enable signal Ex of the driving means 4 is enabled, and the excitation current to the motor windings is turned ON. A field weakening is realized by advancing the magnetic flux by 22.5 degrees from the position where the generated magnetic flux and the magnetic flux of the permanent magnet rotor of the stepping motor 1 are orthogonal to each other.

Since the number of times the second pulse signal PLS2 is applied to the driving means 4 is small and the period is very short, it is not essential to prohibit the excitation enable signal Ex while the second pulse signal PLS2 is being applied. .

Next, a method for realizing four-quadrant operation and field-weakening at the same time will be described.
A method of simultaneously realizing four-quadrant operation and field-weakening uses a second pulse signal PLS2 necessary for mode switching of the four-quadrant operation and a second pulse signal PLS2 corresponding to the phase angle necessary for realizing field-weakening. is applied to the driving means 4 as the pulse signal PLS.

INDUSTRIAL APPLICABILITY The stepping motor drive device according to the present invention is useful for devices using stepping motors used for driving robots and the like.

1 stepping motor 2 position command means 3 rotation control means 4 drive means 5 position detection means 21 control program 22 counter 31 position control section 32 speed control section 33 speed detection section 34 first pulse command section 35 second pulse command section Pc position command Signal Pd Position detection signal Sc Rotation speed command signal Sd Rotation speed detection signal Ic Current setting signal Ex Excitation permission signal PLS1 First pulse signal DIR1 First rotation direction signal PLS2 Second pulse signal DIR2 Second rotation direction signal PLS Pulse signal DIR Rotation Direction signal ECa Phase A excitation current ECb Phase B excitation current

Claims (3)

a rotationally driven stepping motor; position command means for commanding the rotational position of the stepping motor according to a control program; rotation control means for controlling the rotation of the stepping motor; and a position detection means for detecting the rotational position of the stepping motor, wherein the rotation control means detects the difference between the position command signal from the position command means and the position detection signal from the position detection means. a position control unit for outputting the rotational speed from the position detection means, a speed detection unit for calculating the rotational speed from the rotational position of the stepping motor from the position detection means, the rotational speed from the position control unit and the rotational speed from the speed detection unit a speed control unit for outputting a current setting signal from the difference between; a first pulse command unit for outputting a first pulse signal for advancing the stepping motor according to the position detection signal; a second pulse command section for outputting a second pulse signal having a recognizable pulse width and a period shorter than that of the first pulse signal; A drive control device for a stepping motor configured to advance the phase of the stepping motor to a desired angle. 2. The stepping motor drive control device according to claim 1 , wherein said second pulse command section is configured to set a phase advance angle advanced by said second pulse signal to 180 degrees. 3. The apparatus according to claim 1 , wherein the second pulse command section is configured so that the phase advance angle advanced by the second pulse signal can be set within a range of 0 degrees to 90 degrees. Drive control device for stepping motors.

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