JP2003284391A - Anomaly detection device for stepping motor and stepping motor drive unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect step-out and a sign thereof in a stepping motor by a simple system without monitoring the absolute rotational angle of the stepping motor. <P>SOLUTION: A stepping motor drive unit A comprises a pulse signal input portion 90 which inputs a pulse signal b outputted from an encoder 200; a synchronization determination portion 50 which determines as the presence/absence of step-out in a stepping motor B whether the pulse signal b is synchronized with a rotation command pulse a; a determination portion 70 which, if there is an increase or periodical increase and a decrease in the ratio K of the pulse width T1 of the rotation command pulse a and the pulse width T2 of the pulse signal b, determine that there is a sign of overload step-out or overvibration step-out; and a motor control portion 40 provided with a function of stopping the stepping motor B in the case of step-out and, if there is a sign of overload step-out overvibration step-out, correcting a current control value or a rotational speed command value for the stepping motor B so as to prevent overload step- out or overvibration step-out from occurring. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor abnormality detecting device for detecting a step out of a stepping motor and its sign and a stepping motor driving device using the same.

[0002]

2. Description of the Related Art A stepping motor generates a motor current when a rotation command pulse is input to a stepping motor drive device, and as a result, rotates according to the rotation command pulse. However, when it is overloaded or when the rotation speed is rapidly changed, it does not rotate according to the rotation command pulse, and a phenomenon of step-out occurs.

Some conventional stepping motor drive devices are premised on the use of a rotation angle detector for detecting the rotation angle of the stepping motor, and have a function of controlling the stepping motor so as to prevent step-out. . The device monitors the current rotation angle of the motor through the signal output from the rotation angle detector, while monitoring the current command angle of the motor through the rotation command pulse, and stepping so that the deviation between both angles becomes zero. It has a basic configuration for controlling a motor.

[0004]

However, in the case of the above-mentioned conventional example, since the stepping motor is closed-loop controlled and driven in a manner similar to that of the servo motor, the circuit configuration becomes complicated and the cost becomes high. There is an inherent drawback. In particular, since the rotation angle of the stepping motor is monitored in order to detect the stepping out of the motor, a counter with a large bit length is indispensable, which leads to an increase in the circuit scale and downsizing of the device. It has become very difficult to reduce costs.

The present invention was created under the above background, and its main purpose is to easily detect the step-out of the stepping motor and its signs without monitoring the absolute rotation angle of the stepping motor. An object of the present invention is to provide a stepping motor abnormality detection device and a stepping motor drive device that can be detected by a configuration.

[0006]

An abnormality detecting device for a stepping motor according to the present invention includes an encoder for converting the rotation of the stepping motor into a pulse train and outputting it as a pulse signal, and the pulse signal and the stepping motor. It is provided with a synchronization determination unit that determines whether or not synchronization is achieved with the rotation command pulse based on the presence or absence of step-out of the stepping motor, and a step-out warning output unit that outputs the determination result of the synchronization determination unit. ing.

In the synchronization judging section, the ratio K between the pulse width T1 of the pulse signal and the pulse width T2 of the rotation command pulse
It is preferable to use a configuration that detects a change in (= T2 / T1) and determines whether or not the pulse signal and the rotation command pulse of the stepping motor are synchronized based on the detection result. For example, the number of command pulses input between the rising edge of the pulse of the pulse signal and the rising edge of the pulse of the excitation origin signal of the excitation sequence created according to the rotation command pulse is counted, and the change in the count value is counted. Use a structure that is detected as a change in the ratio K,
The number of command pulses input between the rising edge of the pulse of the pulse signal and the rising edge of the pulse of the excitation origin signal of the excitation sequence created according to the rotation command pulse is counted, and the change in the count value is calculated by the ratio K. It is advisable to use a configuration that is detected as a change in.

More preferably, the apparatus has a pulse width T1 of the rotation command pulse and a pulse width T of the pulse signal.
When the ratio K with 2 (= T2 / T1) is increasing, the determination result of the overload step-out symptom determination unit that determines that the stepping motor has an overload step-out symptom and the determination result of the overload step-out symptom determination unit It is desirable to provide an overload step-out warning output unit for outputting Further, a ratio K (= the pulse width T1 of the rotation command pulse and the pulse width T2 of the pulse signal is equal to
To output the determination results of the over-vibration out-of-step symptom determination unit and the over-vibration out-of-step symptom determination unit that determine that the stepping motor has a sign of over-vibration out-of-step when (T2 / T1) periodically increases and decreases. It is desirable to provide an over-vibration out-of-step warning output unit.

In the stepping motor drive device according to the present invention, the pulse signal input section for inputting the pulse signal output from the encoder, the synchronization determination section, and the synchronization determination section determine that the synchronization is not achieved. In this case, the motor control unit has a function of stopping the stepping motor.

More preferably, it is desirable to provide a warning output section for outputting the determination result of the synchronization determination section.

In the stepping motor drive device according to the present invention, the pulse signal input section, the synchronization determination section, the overload step-out symptom determination section, and the overload step-out symptom determination section are used to remove the overload from the stepping motor. A motor control unit having a function of correcting the current control value and / or the rotation speed command value of the stepping motor so as not to cause overload out-of-step when it is determined that there is a sign of a tonality.

More preferably, at least a warning output unit for outputting the determination result of the synchronization determination unit is preferably provided.

In the stepping motor drive device according to the present invention, the pulse signal input section, the synchronization determination section, the over-vibration out-of-step symptom determination section, and the vibration-out-of-step symptom determination section cause the stepping motor to over-vibrate out of step. When it is determined that there is a sign of, a motor control unit having a function of correcting the current control value and / or the rotation speed command value of the stepping motor so that over-vibration out-of-step does not occur.

More preferably, it is desirable to provide at least a warning output unit for outputting the determination result of the synchronization determination unit.

The stepping motor drive device according to the present invention includes a step-out warning input unit for inputting the determination result of the synchronization determination unit output from the step-out warning output unit of the stepping motor abnormality detection device, and the synchronization. And a motor control unit having a function of stopping the stepping motor when the determination unit determines that the synchronization is not achieved.

More preferably, it is desirable to provide a warning output unit for outputting the determination result of the synchronization determination unit.

The stepping motor drive device according to the present invention includes an over-vibration-outage warning input unit for inputting a determination result of the over-vibration-outage warning output unit of the abnormality detection device for the stepping motor, and an over-vibration out-of-step indication. Motor control having a function of correcting the current control value and / or the rotational speed command value of the stepping motor so that the over-vibration out-of-step does not occur when the determination unit determines that the stepping motor has a sign of over-vibration out-of-sync And a section.

More preferably, it is desirable to provide at least a warning output unit for outputting the determination result of the synchronization determination unit.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a stepping motor drive device and a stepping motor abnormality detection device, and FIG. 2 is a diagram for explaining the principle by which the presence or absence of step out of the stepping motor can be detected. And a pulse signal timing chart, FIG. 3 is a diagram for explaining the principle by which the apparatus can detect the sign of stepping motor overload out-of-step, and FIG. 4 is a pulse signal waveform chart. FIG. 6 is a diagram for explaining a principle capable of detecting a sign of excessive vibration out-of-step of a stepping motor, a waveform diagram of a pulse signal, FIG. 5 is a block diagram of a synchronization determination unit of a stepping motor drive device, and FIG. 6 is the same. 7 is a timing chart of various signals of the synchronization determination unit, FIG. 7 is a block diagram showing a modification of the synchronization determination unit, and FIG. 8 is a timing chart of various signals of the synchronization determination unit. Ring chart, FIG. 9 is a block diagram of the determination unit and the signal processing unit of the apparatus, FIG. 10 is a block diagram for explaining another embodiment of a stepping motor driving device and abnormality detecting apparatus for a stepping motor.

The stepping motor driving device A listed here is a device for driving the stepping motor B in response to the input rotation command pulse a, and converts the input commercial alternating current into direct current to generate a motor current. Power supply circuit 1
0, a motor output current control circuit 20 for adjusting the motor current output from the power supply circuit 10, and a bipolar for switching the motor current input through the motor output current control circuit 20 for each phase to generate each phase current. It has a basic configuration including a motor drive circuit 30 which is a switching element group, and a motor control unit 40 which controls the motor output current control circuit 20 and the motor drive circuit 30 according to the rotation command pulse a.

The motor control unit 40 generates a phase excitation signal d obtained by phase-distributing the rotation command pulse a based on a predetermined excitation sequence in order to rotate the stepping motor B in response to the rotation command pulse a and generates a motor drive circuit. An excitation origin signal e indicating that the excitation sequence has returned to the reset position while outputting to 30 (when the phase commander is a five-phase stepping motor, the rotation command pulse a has 20 pulses (during half-step driving) or 10 pulses (full step)). (During driving) A signal that outputs one pulse each time it is input: See Fig. 6)
And an excitation sequence control unit 41 that generates a speed command value v included in the rotation command pulse a by detecting the cycle of the excitation origin signal e, and suppresses an excessive torque output near the middle speed range of the stepping motor B. In order to obtain the optimum current control value corresponding to the speed command value v, the signal processing unit 42 (the detailed configuration of which will be described later) and the motor according to the optimum current control value obtained by the signal processing unit 42 The control signal generator 43 is configured to generate a control signal for controlling the output current control circuit 20.

The stepping motor drive device A is premised on using the encoder 200 which converts the relative rotation angle of the stepping motor B into a pulse train and outputs it as a pulse signal b.

Here, an optical encoder is used as the encoder 200. The encoder 200 is connected to the shaft of the stepping motor B (not shown), and is arranged so as to face a disk having a plurality of slits formed along the circumference on the surface thereof and the disk. It has a light emitting element that emits light toward the slit, and a light receiving element that is arranged at a position facing the light emitting element and that receives light of the light emitting element that has passed through the slit. The pulse signal b is a signal output from the light receiving element. That is, when the disk rotates together with the stepping motor B, the light output from the light emitting element is shielded by the disk or passes through the slit. Therefore, the pulse width and the cycle of the pulse signal b depend on the rotation speed of the stepping motor B. It will change.

In the stepping motor driving device A, the constituent parts described later are newly added to the above-mentioned basic structure, so that the stepping motor B is released based on the pulse signal b and the rotation command pulse a output from the encoder 200. And a sign thereof (here, there are two types: an overload step-out symptom and an over-vibration step-out symptom), and a function of stopping the stepping motor B when it is determined that the stepping motor B is out of step. When it is determined that there is a sign of step out, the stepping motor B is controlled so that the step out does not occur.

The overload step-out sign mentioned here means that the stepping motor B is loaded with a load torque larger than the rated torque.
A step-out symptom that occurs due to a temporal change of the load torque. An over-vibration step-out symptom is a step-out that occurs due to a natural vibration of the stepping motor B and a temporal change of the vibration. Sign of.

Before describing the detailed structure of the stepping motor driving device A, the stepping motor driving device B will be described.
The principle by which the presence or absence of step-out, overload step-out symptom, and over-vibration step-out symptom can be determined will be described with reference to FIGS. 2 to 4.

When the stepping motor B is operating normally, the rotation angle of the stepping motor B accurately changes according to the rotation command pulse a. From this,
As shown in FIG. 5, the rotation command pulse a and the pulse signal b are kept in synchronization with each other, and the phase difference T3 (the rotation command pulse a
From the rise of the pulse signal b) to the phase difference T4 (the time from the rise of the pulse signal b to the rise of the next rotation command pulse a) L
Will always be constant. Further, the ratio K between the pulse width T1 of the rotation command pulse a and the pulse width T2 of the pulse signal b.
(= T2 / T1) is always constant.

However, when the stepping motor B goes out of step, the rotation angle of the stepping motor B does not change in response to the rotation command pulse a, so the phase difference T3 and the phase difference T4 change, and the ratio L changes accordingly. Change appears.
However, when the stepping motor B goes out of step, by its nature, only one of the phase difference T3 and the phase difference T4 does not change. Therefore, it is possible to determine whether or not the stepping motor B is out of step by always detecting only one of the phase difference T3 and the phase difference T4.

When the stepping motor B is not out of step, but the load torque exceeding the rated torque is applied to the stepping motor B, the pulse width T2 of the pulse signal b increases as shown in FIG. The ratio K changes and increases. Even when the frequency of the rotation command pulse a decreases, the pulse width T2 of the pulse signal b increases and the same phenomenon appears, but the pulse width T1 of the rotation command pulse a
Also increases at the same time, so no change appears in the ratio K.
Therefore, by constantly detecting the increase in the ratio K, it is possible to determine whether or not the stepping motor B has a symptom of overload step out. The amount of change in the ratio K generally corresponds to the magnitude of the change in the load torque when the stepping motor B is applied with a torque equal to or higher than the rated torque.

On the other hand, when the stepping motor B is not step-out, but the natural vibration of the stepping motor B occurs in relation to the inertia of the entire load, the pulse width T2 of the pulse signal b changes as shown in FIG. And the ratio K changes accordingly, and periodically increases and decreases. Even when the frequency of the rotation command pulse a changes, the pulse width T2 of the pulse signal b
However, the ratio K does not change because the pulse width T1 of the rotation command pulse a also changes at the same time. Therefore, it is possible to determine whether or not the stepping motor B has a sign of excessive vibration step-out by always detecting the periodic increase and decrease of the ratio K. The amount of change in the ratio K and the frequency of the change are determined by the stepping motor B
It roughly corresponds to the magnitude of the vibration and its frequency.

The stepping motor driving device A has a pulse signal input section 90 for inputting a pulse signal b output from an encoder 200 for converting the relative rotation angle of the stepping motor B into a pulse train as shown in FIG.
And a synchronization determination unit 50 that determines whether or not the pulse signal b and the rotation command pulse a are synchronized with each other as the presence or absence of step out of the stepping motor B, the pulse width T1 of the rotation command pulse a, and the pulse signal b. The pulse width T2 of the pulse width T2 of the pulse width T2 and the pulse width T2 of the pulse width T2 are increased or periodically increased / decreased. Part 5
A warning output unit 80 for outputting 0 and the determination result of the determination unit 70 is provided.

In the determination unit 70, a portion having a function of determining a sign of step-out motor B overload out-of-step is represented as an overload step-out sign determination unit 71, while an excessive vibration step-out of the stepping motor B is detected. A portion having a function of determining a symptom is represented as an over-vibration out-of-step symptom determination unit 72. Similarly, in the warning output unit 80, the synchronization determination unit 5
0, the overload out-of-step warning output unit 81, the overload out-of-step warning output unit 82, the over-vibration out-of-step warning output unit 82, and the over-vibration out-of-step warning output unit 82. Each is shown as a key warning output unit 83.

Further, the signal processing section 42 of the motor control section 40.
The following features have been newly added to. That is, when the synchronization determination unit 50 determines that the stepping motor B is not synchronized, the stepping motor B is stopped by the overload step-out symptom determination unit 71 or the over-vibration step-out symptom determination unit 72. It has a function of correcting the current control value of the stepping motor B so as not to cause overload step out or over vibration step out when it is determined that there is a sign of step out or over vibration step out.

The above-mentioned configuration of the stepping motor driving device A will be described in detail below.

The pulse signal input section 90 is an encoder 200.
It is a terminal for connecting with. The pulse signal b of the encoder 200 is input through the pulse signal input unit 90 and guided to the synchronization determination unit 50.

As shown in FIG. 2, the synchronization determination section 50 determines whether or not the pulse signal b and the rotation command pulse a are synchronized as the presence or absence of step-out of the stepping motor B. It is common to use a configuration in which signals are compared, a reference clock is counted to measure a phase difference T3 or a phase difference T4, and a change in the measured phase difference T3 or the like is detected. However, here, attention is paid to the fact that one command pulse is sufficient as the accuracy of positional deviation of the motor required to detect step-out, and the following simple circuit configuration is used.

That is, as shown in FIG. 6, the periodic signal c is used in place of the pulse signal b, while the excitation origin signal e is used in place of the rotation command pulse a. The phase difference T3 ', which is the time from the rise of b to the rise of the excitation origin signal e, is measured as the number of input pulses of the rotation command pulse a, and the change in the phase difference T3' is detected.

As described above, the periodic signal c is the pulse signal b.
On the other hand, the excitation origin signal e is a signal that is synchronized with the rising edge of the signal, indicating that the current step of the excitation sequence, which sequentially proceeds each time the rotation command pulse a is input in the excitation sequence circuit unit 41, has returned to the reset position. Is. Therefore, there is no problem even if the phase difference T3 ′ is detected instead of detecting the change in the phase difference T3, apart from the accuracy of detecting the step-out of the stepping motor B.

Specifically, it has the configuration shown in FIG.
That is, as shown in FIG. 6, the edge detection unit 51 that generates the periodic signal c synchronized with the rising edge of the pulse signal b and the edge detection unit 51 are set at the rising edge of the periodic signal c, while the excitation origin signal e is set.
RS type F / F52 which is reset by the rising edge of
A counter 53 that counts the rotation command pulse a during the period when the output signal of the F / F 52 is active; a register 54 that latches the count value of the counter 53 every time the periodic signal c becomes active; And a comparator 55 for comparing the output value of the register 54 with the output value of the register 54 and outputting the comparison result as a signal f.

Thus, the phase difference T3 'between the periodic signal c and the excitation origin signal e is sequentially measured as the count value of the counter 53, and this count value is sequentially transferred to the register 54. When the output value of the register 54 indicating the first phase difference T3 ′ is Ca and the output value of the counter 53 indicating the next phase difference T3 ′ is Cb, the comparator 55 compares the magnitudes of Ca and Cb. When Ca = Cb, the comparator 55 outputs the L-level signal f, while Ca ≠ C
When it is b, the comparator 55 outputs an H-level signal f.

The signal f output from the synchronization determination section 50 is L
When it is a level, the phase difference T3 ′ (or the phase difference T
3) is unchanged, and the pulse signal b and the rotation command pulse a are in synchronization with each other, which means that the stepping motor B is not out of step, while the signal f is H level.
When it is a level, the phase difference T3 ′ (or the phase difference T
3) changes appear, and pulse signal b and rotation command pulse a
This means that the stepping motor B is out of synchronization, which means that the stepping motor B is out of synchronization.

Although the accuracy of step-out detection is slightly lowered, a simple circuit configuration as shown in FIG. 7 may be used instead of the synchronization determination section 50.

As shown in FIG. 8, the synchronization determination section 50 'counts the excitation origin signal e every time the edge detection section 51 generates a periodic signal c synchronized with the rising edge of the pulse signal b and the periodic signal c rises. The counter 53 ′ that starts, the register 54 that latches the count value of the counter 53 ′ each time the periodic signal c becomes active, the output value of the counter 53 ′ and the output value of the register 54 ′ are compared, and this comparison is performed. It has a configuration including a comparator 55 that outputs the result as a signal f.

That is, the period T5 indicating the cycle of the cycle signal c is sequentially measured as the count value of 53 'of the counter, and this count value is sequentially transferred to the register 54'. First period T
5, the output value of the register 54 ′ indicating 5 is Ca, and the output value of the counter 53 ′ indicating the next period T5 ′ is Cb,
The comparator 55 compares the sizes of Ca and Cb.
When Ca = Cb, the comparator 55 outputs the L-level signal f, while when Ca ≠ Cb, the comparator 55 outputs the H-level signal f.

When the signal f output from the synchronization determination section 50 'is at the L level, there is no change in the period T5, and the pulse signal b and the rotation command pulse a are in synchronization, and the stepping motor It means that B is not out of sync, but when the signal f is at H level, a change appears in the period T5 and the pulse signal b and the rotation command pulse a.
The stepping motor B is out of synchronization, which means that the stepping motor B is out of synchronization.

The synchronization determining section 50 'can determine whether or not the stepping motor B is out of step based on the change in the period T5 because the number of pulses of the command pulse signal a included in the period of the pulse signal b. Is constant regardless of the rotation speed of the motor.

As shown in FIG. 9, the determination unit 70 receives the pulse signal b and the pulse width data generation unit 1 for detecting the pulse width T2 each time the signal is input, and the excitation origin signal e. A speed command generation unit 2 which detects the cycle as a speed command value v each time the signal is input and a register which sequentially latches the data of the pulse width T2 detected by the pulse width data generation unit 1. Group 3, a register group 4 for sequentially latching the data of the speed command value v detected by the speed command generation unit 2, a temporal change of the pulse width T and the speed command value v, overload step-out and over-vibration release. All combinations of correspondences with the presence or absence of a key sign are recorded in advance as a data table (first database), and both data groups latched by the register groups 3 and 4 are set as input addresses. And outputs high-order bit data (data indicating the presence or absence of signs of overload out-of-step and over-vibration out-of-step) included in the data read from the memory 5 as signals g and h. It has a basic configuration.

In order to determine whether there is a sign of overload step-out or over-oscillation step-out, the ratio K between the pulse width T1 of the rotation command pulse a and the pulse width T2 of the pulse signal b is increased or periodically changed. The need to detect has been described above. In the determination unit 70, the speed command value v (here, the cycle of the excitation origin signal e) included in the rotation command pulse a is used instead of the pulse width T1 of the rotation command pulse a as described above. Moreover, when calculating the ratio K, the ratio K
Of the pulse width T latched in the register groups 3 and 4 is not directly detected.
By the method of accessing the memory 5 based on each information indicating the process of the time change of the speed command value v, bit data indicating the presence or absence of the signs of out-of-step out-of-step and over-vibration out-of-step is obtained. There is.

That is, the rotation command pulse a is applied to the register group 4.
While the information (referred to as information 1) indicating the process of the temporal change of the speed command value v (corresponding to the pulse width T1 of the rotation command pulse a) included in is latched, the pulse signal is stored in the register group 3. Information (referred to as information 2) indicating the process of temporal change of the pulse width T2 of b is latched.

Speed command value v included in the rotation command pulse a
When there is no temporal change in the pulse width T2 of the pulse signal b, the data of the speed command values v included in the information 1 are the same, and the pulse widths T2 included in the information 2 are also the same. At this time, bit data indicating that there is no sign of overload step out and over vibration step out is read from the memory 5.

When the pulse width T2 of the pulse signal b changes with time with respect to the speed command value v included in the rotation command pulse a and increases, each speed command value v included in the information 1 is the same. Information 2 which may or may not change
The pulse width T2 included in the pulse width T2 increases significantly, and at this time, bit data indicating that there is a sign of overload step out is read from the memory 5.

On the other hand, when the pulse width T2 of the pulse signal b periodically increases or decreases with respect to the speed command value v included in the rotation command pulse a, each speed command value v included in the information 1 is the same or While the pulse width T2 included in the information 2 periodically increases and decreases, the bit data indicating that there is a sign of overvibration out-of-step is read from the memory 5 at this time. There is.

The bit data read out from the memory 5 in this way are the signals g and h, and the signal g shows the result of determination as to whether or not there is a sign of overload out-of-step, while the signal h indicates over-vibration out-of-step. The result of determination of the presence or absence of signs is shown.

In addition to the first database, the memory 5 of the judging unit 70 stores the overload out-of-step when there is a sign of a temporal change in the pulse width T and the speed command value v and overload out-of-step or over-oscillation out-of-step. Alternatively, all combinations of the correspondence relation with the correction information regarding the current control value necessary for not causing over-vibration out-of-step are recorded in advance as a database (referred to as a second database). The second database is the signal processing unit 42.
Used in. That is, the memory 5 is shared between the determination unit 70 and the signal processing unit 42.

The signal processing section 42 includes a stepping motor B.
In order to suppress excessive torque output in the vicinity of the medium speed range, all combinations of the current set value and the corresponding relationship between the speed command value v and the optimum current control value are recorded in advance as a database and the data of the current set value is recorded. And the memory 7 in which the data of the speed command value v output from the speed command generation unit 2 is guided to the input address, and the second database is recorded in advance, and each output data of the register groups 3 and 4 is the input address. And the data read from the memory 7 and the data indicating the correction information read from the memory 5 are subtracted from each other, and the data is read as a corrected optimum current control value to the control signal generation unit 43. It has a configuration including a subtracter 8 for outputting and a reset circuit 9 provided between the subtractor 8 and the control signal generation unit 43. The reset circuit 9
The control signal generation unit 43 only when the signal h is at the H level
The optimum current control value input to is reset and the stepping motor B is stopped.

The optimum current control value read from the memory 7 changes according to the current setting value and the current speed command value v, and the motor current is controlled through the motor output current control circuit 20 based on this. It has become so. Therefore, even when the stepping motor B reaches the vicinity of the middle speed range, excessive torque output is suppressed, and approximately uniform output torque is obtained from the low speed range to the high speed range.
Stepping motor drive device A and stepping motor B
The calorific value of is suppressed.

When the synchronization determining section 50 determines that the stepping motor B is out of step during the operation of the stepping motor B, the reset circuit 9 operates through the signal f output from the synchronization determining section 50. When the reset circuit 9 operates, the current setting value input to the control signal generation unit 43 is reset regardless of the operation of the memory 7 or the like,
As a result, the motor current output from the power supply circuit 10 is shut off by the motor output current control circuit 20. Since the motor current is not supplied to the motor drive circuit 30, the stepping motor B is stopped.

Even if the synchronization determining unit 50 does not determine that the stepping motor B is out of step, if there is a sign of out-of-step or out-of-vibration out-of-step, the information 1 in the register group 4 is read from the memory 5. And information 2 of register group 3
The correction information regarding the current control value corresponding to is output.
Then, the optimum current control value output from the memory 7 is corrected by the subtractor 8 based on the correction information output from the memory 70, and the motor output current control circuit 20 is corrected based on the corrected optimum current control value. The motor current is adjusted by. This prevents the occurrence of overload step out or over vibration step out.

In the signal processing unit 42, in order to prevent the occurrence of overload out-of-step or over-vibration out-of-step, the ratio K (= T2 // of the pulse width T1 of the rotation command pulse a and the pulse width T2 of the pulse signal b). Fuzzy control is employed in which fuzzy inference for making T1) constant is performed and the motor current is controlled based on the inference result. The antecedent part of the fuzzy inference is the information 1 and 2 latched in the register groups 3 and 4, while the consequent part is the correction information about the current control value. All the combinations of the input value and the output value of the fuzzy inference are obtained in advance and are recorded in the memory 5 in advance.

Since the signal processing section 42 carries out the fuzzy control as described above, when there is a sign of overload out-of-step, the motor current increases in accordance with the magnitude of the fluctuation of the load torque, while the excessive vibration occurs. When there is a sign of step out, the motor current decreases according to the magnitude of vibration of the stepping motor B. Therefore, even if a sign of overload out-of-step or over-vibration out-of-step appears during operation of the stepping motor B, it is resolved over time unless a large overload or over-vibration occurs, and as a result, overload out-of-step or over-vibration occurs. The occurrence of vibration out-of-step is suppressed.

Here, the optimum current control value output from the memory 7 when a sign of overload out-of-step or over-vibration out-of-sync appears is given as the pulse width T1 of the rotation command pulse a and the pulse width of the pulse signal b. Although the correction is performed so that the ratio K (= T2 / T1) with T2 is constant, the rotation speed command value of the stepping motor B may be corrected instead of or at the same time.

The method of correcting the rotation speed command value in this case is exactly the same as that of the above current control value.
That is, the excitation sequence control unit 41 is controlled based on the correction information regarding the rotation speed command value output from the memory 7 when the symptom of overload step out or over vibration step out appears, and the frequency of the phase excitation signal d is changed. Make adjustments. In particular, when there is a sign of excessive vibration step-out, this can be effectively suppressed, which is advantageous in this respect.

The warning output section 80 has a signal f indicating the determination result of the synchronization determination section 50, a signal g indicating the determination result of the overload step-out symptom determination section 71, and an over-vibration step-out symptom over-vibration step-out symptom determination section 72. The signal h indicating the determination result of is input. The warning output unit 80 is a circuit for lighting a terminal or a light emitting element for outputting these signals to the outside. When the signal f or the signal g becomes active (indicating that there is a sign of overload out-of-step or over-vibration out-of-step) and the signal f becomes active (indicates that out-of-step), The external output of these signals is maintained unless the reset switch or the like is turned on.

In the case of the stepping motor driving device A configured as described above, the pulse signal b is input from the encoder 200, and the stepping motor B is used to control so as not to get out of step, but Since the absolute rotation angle of the stepping motor B is not monitored, this point cannot be said to be the closed loop control of the conventional device. In particular, since the absolute rotation angle of the stepping motor B is not monitored, unlike the conventional apparatus, a large counter having a long bit is unnecessary. From this, the circuit scale is smaller than that of the conventional device, including the point that a memory is used for performing the fuzzy control, and the device can be downsized and the cost can be reduced.

Further, in order to prevent the occurrence of step-out of the stepping motor B, it is determined whether or not there is a sign of step-out of excessive load or step-out of excessive vibration, and appropriate control is performed according to the type. Therefore, the stepping motor B is less likely to be out of step as compared with the conventional device. Moreover, when the stepping motor B goes out of step, the fact that the stepping motor B goes out of step is output to the step out warning output unit 8
Since the motor is output to the outside through 1 and the motor is immediately stopped, it is possible to minimize the influence on the load side that may be caused by the deviation of the rotation angle of the rotor. In this case, when the stepping motor B is driven again, it is necessary to eliminate the cause of the step-out, but the step-out stepping warning output unit 82 or the over-vibration step-out warning output unit 83 causes a step-out failure. Since it is easy to know the type, necessary countermeasures can be taken promptly.
In these respects, it has become possible to improve the performance of the device compared to the conventional device.

As shown in FIG. 1, the synchronization determination section 50, the warning section 70, and the warning output section 80 of the stepping motor drive device A are the constituent parts of the stepping abnormality detection device C together with the encoder 200. . That is, the main part of the stepping abnormality detecting device C is included in the stepping motor driving device A. Instead of such a configuration, the two devices may be separated from each other as shown in FIG. The configurations of both devices in this case are as follows.

The stepping abnormality detecting device C'has a basic structure having an encoder 200, a synchronization judging section 50, a judging section 70 and a warning output section 80, and may be attached to the stepping motor B or externally attached. It may be done. However, since the excitation sequence control unit 41 is not included in the device, it is necessary to add the function of generating the excitation origin signal e from the rotation command pulse a to the determination unit 70 of the device.

On the other hand, unlike the device shown in FIG. 1, the stepping motor driving device A'is not provided with the synchronization determination unit 50, the determination unit 70 and the warning output unit 80, but instead, the stepping abnormality detection device is used. Step-out that is a terminal for inputting each of the signals f, g, and h output from the step-out warning output unit 81, the overload step-out warning output unit 82, and the over-vibration step-out warning output unit 83 of C ′. A warning input unit 100, an overload step-out warning input unit 110, and an over-vibration step-out warning input unit 120 are provided.

Even the stepping motor drive device A'shown in FIG. 10 operates in exactly the same way as in the case shown in FIG. 1 and has the same effect.

[0070]

As described above, the first, second, third, and fourth aspects of the present invention are provided.
When using the stepping motor abnormality detection device according to
Since it is configured to determine whether the stepping motor is out of step or not depending on whether or not the pulse signal output from the encoder and the rotation command pulse of the stepping motor are synchronized, it differs from the conventional example. , A counter with a large bit length is unnecessary. With this,
The circuit scale is reduced, and the device can be downsized and the cost can be reduced.

Further, since the stepping motor is configured to determine whether or not the stepping motor is out of step and to output the determination result, the influence on the load side which may be caused by the stepping motor out of step and the rotational angle of the rotor is deviated. Can be minimized and the performance of the device can be improved.

According to the abnormality detecting device for a stepping motor according to claim 5 of the present invention, since it is configured to determine whether there is a sign of overload step-out of the stepping motor and to output the determination result, In addition to the effects of 1, 2, 3 and 4, even if the stepping motor goes out of step, its type can be easily known, and the countermeasures required at the time of overload step out can be taken promptly. It is possible to improve the performance of the device.

In the case of the abnormality detecting device for a stepping motor according to claim 6 of the present invention, since it is configured to determine whether there is a sign of excessive vibration step-out of the stepping motor and to output the determination result, In addition to the effect 1), even if the stepping motor goes out of step, its type can be easily known, and the necessary countermeasures at the time of over-vibration step out can be promptly taken. It becomes possible to plan.

In the case of the stepping motor drive device according to the seventh aspect of the present invention, the stepping motor is out of synchronization depending on whether or not the pulse signal output from the encoder and the rotation command pulse of the stepping motor are synchronized. Since the presence / absence is determined, unlike the case of the conventional example, it is not necessary to monitor the absolute rotation angle of the stepping motor, and a counter with a large bit length is also unnecessary. Along with this, the circuit scale becomes small, and it becomes possible to reduce the size and cost of the device.

Further, since it is configured to judge whether or not the stepping motor is out of step and to stop the stepping motor at the time of step out, the stepping motor is out of step and the load side which may be generated due to the deviation of the rotation angle of the rotor. The influence can be minimized, and the performance of the device can be improved.

In the case of the stepping motor drive device according to the eighth aspect of the present invention, the stepping motor is out of synchronization depending on whether or not the pulse signal output from the encoder and the rotation command pulse of the stepping motor are synchronized. Since it is configured to determine the presence or absence, the same effect as that of claim 7 is achieved. In addition, since it is configured to determine whether there is a sign of overload out-of-step of the stepping motor and control so that the overload out-of-step does not occur when the sign of overload out-of-step appears, compared to conventional devices. As a result, it is possible to reduce the step-out ratio of the stepping motor, and it is possible to improve the performance of the apparatus in this respect.

In the case of the stepping motor drive device according to the ninth aspect of the present invention, the stepping motor is out of synchronization depending on whether or not the pulse signal output from the encoder and the rotation command pulse of the stepping motor are synchronized. Since it is configured to determine the presence or absence, the same effect as that of claim 7 is achieved. In addition, since it is configured to determine whether there is a sign of over-vibration out-of-step of the stepping motor and control so that the over-vibration out-of-step does not occur when the sign of over-vibration out-of-step appears, compared to conventional devices. As a result, it is possible to reduce the step-out ratio of the stepping motor, and it is possible to improve the performance of the apparatus in this respect.

In the case of the stepping motor drive device according to the tenth aspect of the present invention, the stepping motor drive device is configured to output the determination result as to whether or not the stepping motor is out of step. It is possible to minimize the influence on the load side that may occur due to the step-out of the motor and the deviation of the rotation angle of the rotor, and it is also possible to improve the performance of the device.

According to the eleventh aspect of the stepping motor drive device of the present invention, since the stepping motor is stopped when the stepping motor is out of step, the stepping motor is out of step and the rotation angle of the rotor is deviated. The possible influence on the load side can be minimized, and the performance of the device can be improved.

In the case of the stepping motor driving device according to the twelfth aspect of the present invention, since the stepping motor is controlled so as not to cause the overload step-out when the sign of the step-out step-out appears in the stepping motor, It is possible to reduce the step-out ratio of the stepping motor as compared with the conventional device, and it is possible to improve the performance of the device in this respect.

In the case of the stepping motor drive device according to the thirteenth aspect of the present invention, when the stepping motor shows a sign of excessive vibration step-out, control is performed so as not to cause excessive vibration step-out. It is possible to reduce the step-out ratio of the stepping motor as compared with the conventional device, and it is possible to improve the performance of the device in this respect.

In the case of the stepping motor drive device according to claim 14 of the present invention, since it is configured to output the determination result as to whether or not the stepping motor is out of step, in addition to the effect of claim 11, 12 or 13. As a result, it is possible to minimize the influence on the load side that may occur due to the stepping motor being out of step and the rotational angle of the rotor being deviated, and in this respect it is also possible to improve the performance of the device.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an embodiment of the present invention, and is a configuration diagram of a stepping motor drive device and a stepping motor abnormality detection device.

FIG. 2 is a timing chart of a rotation command pulse and a pulse signal for explaining the principle by which the same device can detect the presence or absence of step-out of a stepping motor.

FIG. 3 is a diagram for explaining the principle by which the same device can detect a sign of out-of-step synchronization of a stepping motor, and is a waveform diagram of a pulse signal.

FIG. 4 is a diagram for explaining the principle by which the same device can detect a sign of out-of-step vibration of a stepping motor, and is a waveform diagram of a pulse signal.

FIG. 5 is a block diagram of a synchronization determination unit of the stepping motor drive device.

FIG. 6 is a timing chart of various signals of a synchronization determination unit of the same device.

FIG. 7 is a block diagram showing a modification of the synchronization determination unit of the same device.

FIG. 8 is a timing chart of various signals of a synchronization determination unit of the same device.

FIG. 9 is a block diagram of a determination unit and a signal processing unit of the same device.

FIG. 10 is a configuration diagram for explaining another embodiment of a stepping motor drive device and a stepping motor abnormality detection device.

[Explanation of symbols]

A Stepping motor drive Rotation command pulse b pulse signal 40 Motor control unit 50 Synchronization determination unit 60 Judgment section 70 Warning output section 90 Pulse signal input section B stepping motor 200 encoder C Stepping motor abnormality detection device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ryuji Ashida             12 Sagahirozawa Minami Shimomano-cho, Ukyo-ku, Kyoto-shi, Kyoto Prefecture             Address within Mycom Co., Ltd. (72) Inventor Nobuichi Nomura             12 Sagahirozawa Minami Shimomano-cho, Ukyo-ku, Kyoto-shi, Kyoto Prefecture             Address within Mycom Co., Ltd. (72) Inventor Katsuhiro Yamaguchi             12 Sagahirozawa Minami Shimomano-cho, Ukyo-ku, Kyoto-shi, Kyoto Prefecture             Address within Mycom Co., Ltd. F-term (reference) 5H580 BB06 FA03 FA04 FA13 FC02                       GG04 HH02 HH08 HH39 JJ02                       JJ09

Claims (14)

[Claims] 1. A stepping motor out-of-step is determined by whether an encoder for converting the rotation of a stepping motor into a pulse train and outputting it as a pulse signal is synchronized with the rotation command pulse of the stepping motor. An abnormality detection device for a stepping motor, comprising: a synchronization determination unit that determines whether or not there is a step, and a step-out warning output unit that outputs a determination result of the synchronization determination unit. 2. The stepping motor abnormality detection device according to claim 1, wherein the synchronization determination unit changes the ratio K (= T2 / T1) between the pulse width T1 of the pulse signal and the pulse width T2 of the rotation command pulse. Is detected and whether or not the pulse signal and the rotation command pulse of the stepping motor are synchronized based on the detection result is detected. 3. The stepping motor abnormality detection device according to claim 2, wherein the synchronization determination section causes the pulse of the pulse of the pulse signal and the pulse of the excitation origin signal of the excitation sequence created in response to the rotation command pulse to rise. An abnormality detection device for a stepping motor, characterized in that the number of command pulses input between the two is counted, and a change in the count value is detected as a change in the ratio K. 4. The stepping motor abnormality detection device according to claim 2, wherein the synchronization determination unit is the number of pulses of the excitation origin signal input between the rising of the pulse of the pulse signal and the rising of the next pulse. Is detected and the change in the count value is detected as a change in the ratio K. 5. The abnormality detecting device for a stepping motor according to claim 2, 3 or 4, wherein a ratio K (= T) of the pulse width T1 of the rotation command pulse and the pulse width T2 of the pulse signal.
2 / T1) is increasing, an overload step-out symptom determination unit that determines that the stepping motor has a symptom of over-load step-out synchronism, and an overload for outputting the determination result of the overload step-out symptom determination unit An abnormality detecting device for a stepping motor, comprising: a step-out warning output unit. 6. The stepping motor abnormality detecting device according to claim 2, 3 or 4, wherein a ratio K between a pulse width T1 of the rotation command pulse and a pulse width T2 of the pulse signal.
When (= T2 / T1) is periodically increased / decreased, the determination result of the over-vibration-outage symptom determination unit and the over-vibration-outage symptom determination unit that determine that the stepping motor has an over-oscillation out-of-step symptom is output. An abnormal vibration out-of-step warning output unit for operating the stepping motor abnormality detection device. 7. A stepping motor drive device for driving a stepping motor according to an input rotation command pulse, and a pulse signal input section for inputting a pulse signal output from the encoder according to claim 1. 3. A stepping motor drive device comprising: 3 or 4 synchronization determination units; and a motor control unit having a function of stopping the stepping motor when the synchronization determination unit determines that the synchronization is not achieved. 8. A stepping motor drive device for driving a stepping motor according to an input rotation command pulse, the pulse signal input section according to claim 7, and the synchronization determination section according to claim 2, 3 or 4. When the overload out-of-step symptom determination unit 5 and the overload out-of-step symptom determination unit determine that the stepping motor has an overload out-of-step symptom, the current control value of the stepping motor is set so that the overload out-of-step does not occur. And / or a motor control unit having a function of correcting a rotation speed command value, and a stepping motor drive device. 9. A stepping motor drive device for driving a stepping motor according to an input rotation command pulse, the pulse signal input section according to claim 7, and the synchronization determination section according to claim 1, 2, 3 or 4. The over-vibration step-out symptom determination unit according to claim 6 and the current control of the stepping motor so that the over-vibration out-of-step does not occur when the step-out motor has a symptom of over-vibration out-of-step. And a motor control unit having a function of correcting the rotation speed command value. 10. The stepping motor drive device according to claim 7, 8 or 9, further comprising a warning output unit for outputting at least the determination result of the synchronization determination unit. 11. A stepping motor drive device for driving a stepping motor in response to an input rotation command pulse, wherein the stepping warning output section of the stepping motor abnormality detection device according to claim 1, 2, 3 or 4 outputs. A step-out warning input unit for inputting the determination result of the synchronization determination unit, and a motor control unit having a function of stopping the stepping motor when the synchronization determination unit determines that the synchronization is not achieved. A stepping motor drive device characterized by: 12. A stepping motor drive device for driving a stepping motor according to an input rotation command pulse, for inputting a determination result of an overload step-out warning output unit of an abnormality detection device for a stepping motor according to claim 5. When the overload out-of-step warning input unit and the overload out-of-step sign determination unit determine that the stepping motor has a sign of overload out-of-step, the current control value of the stepping motor is set so that the overload out-of-step does not occur. And / or a motor control unit having a function of correcting a rotation speed command value, and a stepping motor drive device. 13. A stepping motor drive device for driving a stepping motor according to an input rotation command pulse, for inputting a determination result of an over-vibration out-of-step warning output unit of an abnormality detection device for a stepping motor according to claim 6. The over-vibration step-out warning input section and the over-vibration step-out symptom determination section determine that the stepping motor current control value and the And / or a motor control unit having a function of correcting a rotation speed command value, and a stepping motor drive device. 14. The stepping motor drive device according to claim 11, 12 or 13, further comprising a warning output unit for outputting at least a determination result of the synchronization determination unit.