JPH0640754B2 - Stepping motor drive - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stepping motor drive device for driving a stepping motor in fine divisions.

[Prior Art] In a general stepping motor drive device, a basic step angle [= 360 / (2 · H · S) (where H is the number of teeth of a rotor) is taken in one step each time a step command pulse is input. , S is the number of phases)]. In addition, a microstep (fine division drive) type drive device that advances each step of dividing a basic step angle into 1 / M (where M is the number of divisions of the basic step angle) each time a step command pulse is input. There is also.

For example, in the conventional fine division driving device disclosed in Japanese Patent Laid-Open No. 57-110099, the pattern of the excitation current value setting signal required for performing the fine division driving is stored in the memory in advance. Then, each time a step command pulse is generated, an address signal that advances by a division step is created, and an exciting current value setting signal indicating the exciting current value of each exciting winding corresponding to the address signal is obtained from the memory, and the exciting current is set. Fine division driving is performed by exciting a predetermined exciting winding based on the value setting signal.

Further, Japanese Patent Laid-Open No. 53-106411 discloses a technique of changing the step number of the dividing step by changing the number of divisions M described above.

[Problems to be Solved by the Invention] However, in a drive unit adopting a conventional fine division drive method in which each time a step command pulse is input, a step is performed at a division step of 1 / M of a basic step angle, three divisions are made. In order to advance by one step, three stepping command pulses must be input to perform three step operations. As in the drive device disclosed in Japanese Patent Laid-Open No. 53-106411, if the division number M is changed, the step amount (step angle) by one step operation can be changed. However, in this drive device, since the step angle can be changed only so as to always divide one basic step angle range into M equal parts, there is a problem that an arbitrary step angle suitable for the purpose cannot be obtained.

An object of the present invention is to provide a stepping motor drive device that can arbitrarily set a step angle.

[Means for Solving Problems] A configuration of the present invention for achieving the above object will be described with reference to FIGS. 1 to 5 corresponding to the embodiments. The present invention includes an address calculation circuit 11 that outputs an address signal indicating a target step position each time a step command pulse is generated,
Each memory 12 and 13 corresponding to the address signal indicating the target step position is provided from the memories 12 and 13 each time an address signal is input, provided with the memories 12 and 13 for storing the pattern of the exciting current value setting signal necessary for performing the fine division driving. Exciting current value setting signal forming circuits 16 and 17 for outputting an exciting current value setting signal indicating an exciting current value of the exciting winding, and exciting current value setting signals and phase switching signals from the exciting current value setting signal forming circuits 16 and 17. And a stepping motor drive unit 18 for performing fine division drive by exciting a predetermined exciting winding on the basis of the exciting current value setting signal as an input signal.

In the present invention, the address calculation circuit 11 is configured as follows. First, the address arithmetic circuit 11 sets the basic step angle of the stepping motor to 1 / M (where
M is the number of divisions of the basic step angle) and the second input terminal Td to which the division number setting signal m that indicates division is input, and the basic step angle is 1 / M (where M is the number of divisions of the basic step angle). The third input terminal Tc to which the step number setting signal n indicating that N (where N is a positive integer) steps of the division steps
And a fourth input terminal Ta to which a step command pulse is input. The address calculation circuit 11 includes a first adder / subtractor 1, a discriminator 3, a second adder / subtractor 4, a selection circuit 5, a latch circuit 6, a delay circuit 8, and a phase switching signal output circuit 9. It is equipped with.

The first adder / subtractor 1 uses the step number setting signal n and the current position signal p indicating the current step position P as input signals, adds P + N = K when the rotation direction input signal is a normal rotation signal, and adds the rotation direction. When the input signal is a reverse signal, P-N =
K is subtracted, and an output signal k indicating the target step position K based on the current step position P is output.

The discriminator 3 uses the output signal k and the division number setting signal m as input signals to determine whether or not there is a need for phase switching, and K ≧
When M or K ≦ 0, a determination signal indicating phase switching is output, and when M>K> 0, a determination signal indicating that phase switching is unnecessary is output.

The second adder / subtractor 4 outputs an output signal k, a division number setting signal m, in order to obtain an output signal y indicating a target step position Y with reference to the phase switching step position when performing phase switching.
Using the rotation direction input signal as an input signal, (P + N) -M = Y is added when the rotation direction input signal is a normal rotation signal, and (P-N) + M = Y is added and subtracted when the rotation direction input signal is a reverse rotation signal. To output the output signal y.

The selection circuit 5 selects the output signal z indicating the target step position when the phase switching is performed and when the phase switching is not performed, and the output signal k, the output signal y, and the discriminator 3 are selected.
When the discrimination signal indicating the phase switching is input from the discriminator 3, the output signal y of the second adder / subtractor 4 is selected as the output signal z, and the discriminator 3 switches the phase. When the discrimination signal indicating that is unnecessary is input, the output signal k of the first adder-subtractor 1 is output as the output signal z.

The latch circuit 6 latches the output signal z of the selection circuit 5 at the rising edge of the step command pulse each time the step command pulse is applied, and outputs the output signal z as the address signal ad.

The delay circuit 8 delays the address signal ad with a time width wider than the pulse width of the step command pulse and outputs it as the current position signal p.

The phase switching signal output circuit 9 uses the step command pulse and the discrimination signal of the discriminator 3 as input signals, and when the discrimination signal indicating the phase switching is input from the discriminator 3, uses the step command pulse as a phase switching signal. Output.

[Operation] In the drive device of the present invention, the target step position K based on the current step position P is determined by the first adder / subtractor 1, and the phase switching step position is determined when the second adder / subtractor 4 performs phase switching. The target step position Y based on is calculated. Further, the selection circuit 5 selects the target step position Y obtained by the second adder / subtractor 4 when the discrimination signal indicating the phase switching is input from the discriminator 3, and the phase switching from the discriminator 3 is unnecessary. When the discrimination signal indicating is input, the target step position K obtained by the first adder / subtractor is selected. Discriminator 3
When a discriminating signal indicating phase switching is output from, the phase switching signal output circuit 9 outputs a phase switching signal to the stepping motor drive unit 18 to switch the phase to be excited. This allows the selection circuit 5 to select the target step position Y based on the phase switching step position. As a result, 1 is obtained each time one step command pulse is generated.
The fine division step can be set to N / M of the basic step angle. Further, by using the latch circuit 6 and the delay circuit 8, occurrence of malfunction is prevented.

[Embodiment] An embodiment of the stepping motor drive device of the present invention will be described in detail below. 1 to 5 are diagrams used for explaining the configuration of a drive device in which the present invention is applied to drive a two-phase stepping motor. As shown in FIGS. 1 and 2, this stepping motor drive device includes an address calculation circuit 11, first and second excitation current value setting signal forming circuits 16 and 17, and a stepping motor drive unit 18. Composed of. The address calculation circuit 11 sets the basic step angle of the stepping motor to the first input terminal Tb to which a rotation direction input signal indicating forward rotation and reverse rotation is input, 1 / M (where M is the division number of the basic step angle). The second input terminal Td to which the division number setting signal m indicating division is input, and N of division steps obtained by dividing the basic step angle into 1 / M (where M is the division number of the basic step angle).
(However, N is a positive integer.) A third input terminal Tc to which a step number setting signal n indicating that one step is one fine division step is input, and a fourth step command pulse is input.
Input terminal Ta. The address calculation circuit 11 includes a first adder / subtractor 1, a discriminator 3, a second adder / subtractor 4, a selection circuit 5, a latch circuit 6, a delay circuit 8, and a phase switching signal output circuit 9. Composed of.

The first adder / subtractor 1 receives the rotation direction input signals for forward rotation and reverse rotation, and the basic step angle [= 360
/ (2 · H · S) (where H is the number of teeth of the rotor and S is the number of phases)] is divided into 1 / M (where M is the number of divisions of the basic step angle) and N steps (however , N
Is a positive integer) and the step number setting signal n that determines to step by step, and the current position signal p that indicates the current step position P
Using as input signals, P + N = K is added when the rotation direction input signal is the forward rotation signal, and P−N = K is subtracted when the rotation direction input signal is the reverse rotation signal, and the output signal k is output. It is like this. In this way, the first adder / subtractor 1
Target step position K based on the current step position P
To output the output signal k. The output signal k of the first adder / subtractor 1 is provided to the discriminator 3, the second adder / subtractor 4, and the selection circuit 5.

The discriminator 3 uses the output signal k and the division number setting signal m that determines the division number M of the basic step angle of the stepping motor 2 as input signals to determine whether K ≧ M or K ≦ 0, thereby performing phase switching. To determine the necessity of. The discriminator 3 is K
When .gtoreq.M or K.ltoreq.0, a determination signal indicating phase switching is output, and when M>K> 0, a determination signal indicating that phase switching is unnecessary is output.

The second adder / subtractor 4 outputs the output signal k and the division number setting signal m.
And a rotation direction input signal as input signals, and if the rotation direction input signal is a normal rotation signal, Y = (P +
N) -M is output, and if the signal is a reverse rotation signal, Y = (P-N) + M is output as the output signal y. That is, the second adder / subtractor 4 uses the phase switching step position (the third
An output signal y indicating the target step position Y with reference to the position "0" in the figure) is obtained.

The output signal y is input to the selection circuit 5 together with the output signal k. The selection circuit 5 selects the output signal z indicating the target step position when the phase switching is performed and when the phase switching is not performed. From the discriminator 3 in the forward rotation state, K ≧
Discrimination signal indicating M (discrimination signal indicating phase switching)
Is input, Y = (P + N) -M as the output signal z
Is output. In the normal rotation state, M>K>
If the discriminating signal indicating that phase switching is unnecessary is input at 0, the output signal k indicating K = P + N is output as the output signal z. When a determination signal indicating K ≦ 0 (determination signal indicating phase switching) is input in the reverse rotation state, the output signal z
Output signal y indicating Y = (P−N) + M as
If M>K> 0 in the reverse rotation state and a determination signal indicating that phase switching is not required is input, K = P as the output signal z.
The output signal k indicating -N is selected and output.

The output signal z of the selection circuit 5 is applied to the latch circuit 6. The latch circuit 6 latches the output signal z of the selection circuit 5 at the rising edge of the step command pulse each time the step command pulse is given, and outputs the output signal z from the output terminal 7 as an address signal ad.

Further, the address signal ad is applied to the delay circuit 8. The delay circuit 8 delays the address signal ad with a time width wider than the pulse width of the step command pulse and outputs it as the current position signal p to the first adder / subtractor 1.

The output signal of the discriminator 3 is also applied to the phase switching signal output circuit 9. The phase switching signal output circuit 9 receives the step command pulse and the discrimination signal (discrimination signal indicating phase switching) indicating whether K ≧ M or K ≦ 0 of the discriminator 3 as an input signal,
When ≧ M or K ≦ 0, the step command pulse is output from the output terminal 10 as a phase switching signal.

The address signal ad output from the output terminal 7 is a first and a first read-only memory (hereinafter referred to as ROM).
It is adapted to be input to the second memories 12 and 13. The first memory 12 stores the rising pattern (for example, the rising pattern PT1 in FIG. 4) of the exciting current value setting signal of the basic step angle of the stepping motor 2, and the rising pattern is stored every time the address signal ad is input. A digital weighting signal corresponding to the rising pattern of the exciting current value setting signal corresponding to the address is output. The second memory 13 stores the falling pattern (for example, the falling pattern PT2 of FIG. 4) of the exciting current value setting signal of the basic step angle of the stepping motor 2, and every time the address signal ad is input. In addition, a digital weighting signal corresponding to the falling pattern of the exciting current value setting signal corresponding to the address is output.

The weighted signals from the first and second memories 12 and 13 are input to the first and second digital / analog converters (hereinafter referred to as D / A converters) 14 and 15, respectively. There is. These first and second D / A converters 1
Reference numerals 4 and 15 are adapted to D / A convert the weighting signal and output an analog excitation current value setting signal.

The first memory 12 and the second D / A converter 14 form a first exciting current value setting signal forming circuit 16. The first exciting current value setting signal forming circuit 16 is adapted to sequentially output the exciting current value setting signal in a predetermined rising pattern every time the address signal ad is input.

Further, the second memory 13 and the second D / A converter 15 form a second exciting current value setting signal forming circuit 17. The second exciting current value setting signal forming circuit 17 is adapted to sequentially output the exciting current value setting signal in a predetermined falling pattern every time the address signal ad is input.

These first and second exciting current value setting signal forming circuits 16,
Each excitation current value setting signal from 17 is applied to the stepping motor drive unit 18. The stepping motor drive unit 18 uses two kinds of exciting current value setting signals as input signals to excite the stepping motor 2 as shown in FIG. 5, and the exciting currents IA, IB, I, and
I respectively, and these exciting currents IA, IB, I
, I based on the phase switching signal and applied to the exciting winding of a predetermined phase of the stepping motor 2.

Next, the operation of the stepping motor driving device incorporating such an address arithmetic circuit 11 will be described by taking the case where the basic step angle is divided into eight (M = 8) as shown in FIG. For example, when the rotation direction input signal is a normal rotation signal and the step number setting signal n indicates N = 3 (that is, N / M = 3/8), the current position signal p
Indicates P = 1 between A phase and B phase, the first adder / subtractor 1 adds K = P + N = 1 + 3 = 4. Since the discriminator 3 inputs K = 4 and M = 8, it determines that the phase switching is unnecessary in other cases where neither K ≧ M nor K ≦ 0. In the second adder / subtractor 4, since the normal rotation signal is input, Y = (P + N)-
Subtraction of M = (1 + 3) -8 = -4 is performed and Y = -4 is output. In the selection circuit 5, since the discriminator 3 determines that phase switching is not necessary, the output signal k is selected and output as the output signal z. This output signal k is latched by the latch circuit 6 at the rising edge of the step command pulse, and AD = 4 is output as the address signal ad. In this case, since the discriminator 3 has determined that phase switching is unnecessary, the phase switching signal output circuit 10 does not output the phase switching signal even when the step command pulse is input. Therefore, the stepping motor 2 is driven to rotate normally in one step from the address AD = 1 between the A phase and B phase to the angle corresponding to the address AD = 4 between the A phase and B phase. The exciting current value setting signals are formed in the exciting current value setting signal forming circuits 16 and 17 of the stepping motor drive unit 1
At 8, a corresponding exciting current of each phase is formed.

Next, for example, if the rotation direction input signal is a normal rotation signal,
When the step number setting signal n indicates N = 3 and the current position signal p indicates P = 7 between the A phase and the B phase, K = P + N = 7 + 3 = in the first adder / subtractor 1. Add 10. In the discriminator 3, K = 10 is input and M =
Since 8 is input, it is determined that K> M, that is, phase switching is necessary. Since the normal signal is input to the second adder / subtractor 4, the subtraction Y = (P + N) -M = 10-8 = 2 is performed and Y = 2 is output. In the selection circuit 5, since the discriminator 3 has determined that K> M, that is, phase switching is required, the output signal y is selected and output as the output signal z. This output signal y is latched by the latch circuit 6 at the rising edge of the step command pulse, and the address signal a
AD = 2 is output as d. In this case, since the discriminator 3 has determined that K> M, that is, phase switching is necessary, the phase switching signal output circuit 10 outputs the step command pulse as a phase switching signal. Therefore, the stepping motor 2 is 1 from the address AD = 7 between the A phase and the B phase to the angle corresponding to the address AD = 4 between the B phase.
Excitation current value setting signals are formed in the first and second excitation current value setting signal forming circuits 16 and 17 so that the stepping motor drive unit 18 excites each phase in accordance with the excitation current value setting signals. An electric current is formed.

Next, for example, if the rotation direction input signal is a reverse rotation signal,
When the current position signal p indicates P = 6 between the A phase and the B phase when the step number setting signal n indicates N = 3, K = 6-3 = in the first adder / subtractor 1. Subtract 3 In the discriminator 3, since K = 3 is input and M = 8 is input, it is determined that K <M and neither K ≧ M nor K ≦ 0, that is, phase switching is unnecessary. Second adder / subtractor 4
Then, since the reverse rotation signal is input, Y = (P−N) + M
= 3 + 8 = 11, and Y = 11 is output.
In the selection circuit 5, since the discriminator 3 determines that phase switching is not necessary, the output signal k indicating K = 3 is selected and output as the output signal z. This output signal z is latched by the latch circuit 6 at the rising edge of the step command pulse, and AD = 3 is output as the address signal ad. In this case, since the discriminator 3 determines that phase switching is not necessary, the phase switching signal output circuit 10 does not output the phase switching signal even when the step command pulse is input. Therefore, the stepping motor 2 is reversely driven in one step from the address AD = 6 between the A phase and B phase to the angle corresponding to the address AD = 3 between the A phase and B phase.
The second exciting current value setting signal forming circuits 16 and 17 form an exciting current value setting signal, and the stepping motor drive unit 18 forms an exciting current of each phase corresponding thereto.

Next, for example, if the rotation direction input signal is a reverse rotation signal,
When the current position signal p indicates P = 1 between the A phase and the B phase when the step number setting signal n indicates N = 3, K = 1-3 = in the first adder / subtractor 1. -2 is subtracted. In the discriminator 3, since K = -2 and M = 8 are input, it is determined that K <0, that is, phase switching is necessary. In the second adder / subtractor 4, since the reverse rotation signal is input, the addition Y = (P−N) + M = −2 + 8 = 6 is performed and Y = 6 is output. In the selection circuit 5, the discriminator 3 is K
Since it is determined that <0, that is, phase switching is necessary, the output signal y is selected and output as the output signal z. This output signal y is latched by the latch circuit 6 at the rising edge of the step command pulse, and AD is output as the address signal ad.
= 6 is output. In this case, since the discriminator 3 has determined that K <0, that is, phase switching is necessary, the phase switching signal output circuit 10 outputs the step command pulse as a phase switching signal. Therefore, the stepping motor 2 starts from the address AD between the phase A and the phase B to the address AD between the phase A and the phase AD.
= 6, the exciting current value setting signals are formed by the first and second exciting current value setting signal forming circuits 16 and 17 so that the stepping motor driving unit 18 is driven in reverse by one step. Then, the exciting current of each phase is formed in accordance with this.

In this embodiment, by changing the division number setting signal m supplied to the second adder / subtractor 4, it is possible to form an address signal for performing control for performing desired fine division driving in the same circuit. Further, by changing the number of steps N given to the first adder / subtractor 1, an arbitrary fine division step is selected in the same circuit to form an address signal for performing control for fine division drive at a desired step angle. You can As described above, in the present embodiment, since the step angle of one fine division step can be easily changed, the step angle of one fine division step is set to a fine angle at a low speed, that is, the number N of steps is reduced to obtain smooth rotation. At a high speed, the number of steps N can be increased to bring the step angle of one fine division step closer to or closer to the basic step angle to form an address signal for high speed rotation. Fine angle drive is required to perform smooth low-speed rotation, but fine angle drive requires a higher frequency for the step command pulse if the conventional structure is used at high speeds, which increases the cost of the parts used and disturbance noise. Although there is a problem that the stepping motor is weakened, according to the present embodiment, such a problem can be solved by switching the step setting number N, the cost is not increased, and the stepping motor control address is strong against the disturbance noise. An arithmetic circuit can be provided. Further, according to this embodiment, there is an advantage that the feed pitch of a ball screw or the like can be easily switched.

In the above embodiment, the case where the present invention is applied to the driving of the two-phase stepping motor has been described, but the present invention is not limited to this, and can be similarly applied to the driving of the n-phase stepping motor.

Further, in the above embodiment, the memory of the exciting current value setting signal forming circuit stores only the rising or falling pattern of the exciting current value setting signal, but the one cycle pattern of the exciting current value setting signal is stored in the memory. May be. The exciting current value setting signal forming circuit may be provided for each phase of the stepping motor.

[Effect of the Invention] According to the drive device of the present invention, one fine division step obtained each time one step command pulse is generated can be set to N / M of the basic step angle, so that the basic step angle of 1 / M
It is possible to easily obtain an arbitrary step angle that suits the purpose, as compared with the conventional method in which 1 subdivision step is set. By using the latch circuit and delay circuit,
Occurrence of malfunction can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of the configuration of an address arithmetic circuit used in a stepping motor drive device according to the present invention,
FIG. 2 is a block diagram showing a schematic configuration of an example of a stepping motor driving device, FIG. 3 is an explanatory diagram showing an example of a finely divided state of a basic step angle, and FIG. 4 shows a relationship between an address and an exciting current value setting signal. FIG. 5 is a waveform diagram showing the exciting current of each phase. 1 ... first adder / subtractor, 2 ... stepping motor, 3
...... Discriminator, 4 …… Second adder / subtractor, 5 …… Selection circuit,
6 ... Latch circuit, 8 ... Delay circuit, 9 ... Phase switching signal output circuit, 11 ... Address arithmetic circuit.

Claims (1)

[Claims] 1. An address arithmetic circuit that outputs an address signal indicating a target step position each time a step command pulse is generated, and a memory that stores a pattern of an excitation current value setting signal necessary for performing fine division driving. An excitation current value setting signal that outputs an excitation current value setting signal indicating an excitation current value of each excitation winding corresponding to the address signal indicating the target step position from the memory every time the address signal is input Fine-division driving by exciting a predetermined exciting winding on the basis of the forming circuit and the exciting current value setting signal and the phase switching signal from the exciting current value setting signal forming circuit based on the exciting current value setting signal. And a stepping motor driving unit for driving the stepping motor driving unit, wherein The basic step angle of the stepping motor is 1
/ M (where M is the number of divisions of the basic step angle) and the second input terminal to which the division number setting signal m indicating division is input, and the basic step angle is 1 / M (where M is the basic number). N of division steps divided into the number of divisions of the step angle)
(However, N is a positive integer.) A third input terminal to which a step number setting signal n indicating that one minute division step is input and a fourth input terminal to which a step command pulse is input And using the step number setting signal n and the current position signal p indicating the current step position P as input signals, when the rotation direction input signal is a forward rotation signal, P + N = K is added to obtain the rotation direction. When the input signal is a reverse rotation signal, PN = K is subtracted, and a first adder / subtractor that outputs an output signal k indicating a target step position K based on the current step position P and phase switching The output signal k for determining the necessity or non-necessity
And the division number setting signal m as input signals, a discrimination signal indicating phase switching is output when K ≧ M or K ≦ 0, and M> K
In order to obtain a discriminator that outputs a discrimination signal indicating that phase switching is unnecessary when> 0, and an output signal y indicating a target step position Y based on the phase switching step position when performing phase switching. , The output signal k, the division number setting signal m, and the rotation direction input signal are input signals, and the rotation direction input signal is a normal rotation signal, (P + N) -M = Y, the rotation direction input signal Is a reverse signal, a second adder / subtractor for adding / subtracting (PN) + M = Y to output the output signal y, and the target step in the case of performing phase switching and in the case of not performing phase switching In order to select the output signal z indicating the position, the discrimination signal indicating the phase switching is input from the discriminator using the output signal k, the output signal y and the discrimination signal from the discriminator as input signals. When it is being said The output signal y of the second adder / subtractor is selected as the output signal z, and the output signal of the first adder / subtractor is input when a determination signal indicating that the phase switching is unnecessary is input from the determiner. a selection circuit that outputs k as the output signal z; and a latch that outputs the output signal z of the selection circuit as the address signal ad by latching the output signal z at the rising edge of the advance command pulse every time the step command pulse is given. A circuit, a delay circuit that delays the address signal ad with a time width wider than the pulse width of the step command pulse and outputs the current position signal p, the step command pulse, and the discrimination signal of the discriminator. When the discrimination signal indicating the phase switching is input from the discriminator as the input signal, the stepping command pulse is used as the phase switching signal. And a phase switching signal output circuit for outputting to a motor drive unit.