JP7294917B2 - Stepping motor control device, stepping motor control method - Google Patents

Description

The present invention relates to a configuration of a control device for controlling the driving of a stepping motor and a control method thereof, and more particularly to a technique effectively applied to a stepping motor used in applications where the load state changes.

Stepping motors, which can accurately control the rotation angle and rotation speed by position commands (pulse signals), are widely used in various fields, such as driving the XY axis table of industrial equipment and the driving mechanism of medical equipment such as dispensing equipment. used. A stepping motor moves a rotor in response to a position command (pulse signal), and is open-loop control in which the current flowing through each winding phase is controlled to be constant, and a simple positioning operation can be realized.

However, when a load greater than the motor torque generated by the aforementioned current is applied, the stepping motor falls into a step-out state in which it cannot follow the position command (pulse signal).

In order to prevent this, it is necessary to apply a current that takes into account the maximum load, but the output torque of the stepping motor tends to oscillate and the reactive power increases, which causes the problem that the stepping motor tends to generate heat.

Therefore, for example, as in Patent Document 1, the zero crossing of the current flowing through each phase winding of the stepping motor is detected, and the rise or fall edge signal of the position command (pulse signal) given to the driver is used. , detecting the phase difference up to the zero crossing of the current, and varying the current setting of the driver according to the phase difference ratio, which is the ratio of the phase difference to the period between the edges, and the drive frequency of the stepping motor. (Paragraph [0008] of Patent Document 1)

JP 2011-147236 A

However, since stepping motors generally have multiple poles and the electric angular frequency of the current is high, it is very difficult to detect the zero crossing of the current when the method of Patent Document 1 is used. Since general-purpose microprocessors cannot sufficiently cope with this problem, a dedicated microprocessor is required for each stepping motor specification, which leads to an increase in cost.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide stepping motor control that enables low-cost, high-accuracy torque estimation and out-of-step estimation without requiring a position sensor such as an encoder or a dedicated microprocessor in stepping motor drive control. An object of the present invention is to provide an apparatus and its control method.

In order to solve the above-described problems, the present invention provides a stepping motor control device for controlling the driving of a stepping motor, comprising a drive driver for controlling the output voltage and rotation speed of the stepping motor, and detecting the output voltage of the stepping motor. a voltage detector that detects the output current of the stepping motor, a voltage detection value detected by the voltage detector, a current detection value detected by the current detector, and speed information of the stepping motor a torque/step-out estimating unit for estimating the output torque and electromotive voltage phase of the stepping motor, wherein the torque/step-out estimating unit extracts a fundamental wave component of the voltage detection value detected by the voltage detector. a first first-order lag filter, a second first-order lag filter for extracting a fundamental wave component of a current detection value detected by the current detector, an output value of the first first-order lag filter, and the second first-order lag a torque estimating unit for calculating an output torque estimated value from a filter output value and the speed information; an output value of the first first-order lag filter, an output value of the second first-order lag filter, and a stepping motor circuit; a phase estimator that calculates an electromotive voltage phase estimate from a set value of winding resistance that is a constant; a period calculator that calculates a period that is the reciprocal of the speed information from the speed information; the electromotive voltage phase estimate; A step-out estimating unit that sets a control signal for the drive driver based on the cycle, and controls driving of the stepping motor based on the output torque estimated value and electromotive voltage phase estimated value estimated by the torque/step-out estimating unit. characterized by

The present invention also provides a stepping motor control method for controlling driving of a stepping motor, which detects an output voltage and an output current of the stepping motor, detects the detected voltage detection value and current detection value, and detects the speed of the stepping motor. estimating the output torque and electromotive voltage phase of the stepping motor from the information, extracting fundamental wave components of the voltage detection value and the current detection value, extracting the fundamental wave components of the voltage detection value and the current detection value, and An output torque estimated value is calculated from the speed information, and an electromotive voltage phase estimated value is calculated from the fundamental wave component of the extracted voltage detection value and current detection value, and the setting value of the winding resistance, which is the circuit constant of the stepping motor. calculating a cycle that is the reciprocal of the speed information from the speed information, setting a control signal for a driving driver of the stepping motor based on the estimated electromotive voltage phase value and the cycle, and calculating the estimated output torque and the estimated output torque; The driving of the stepping motor is controlled based on the voltage phase estimation value.

According to the present invention, in drive control of a stepping motor, there is no need for a position sensor such as an encoder or a dedicated microprocessor, and the stepping motor control device is capable of low-cost, highly accurate torque estimation and out-of-step estimation. The control method can be realized.

This enables highly efficient and highly reliable stepping motor drive control.

Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is a configuration diagram of a stepping motor control device according to a first embodiment; FIG. 2 is a configuration diagram of a torque/out-of-step estimating unit in FIG. 1; FIG. FIG. 10 is a configuration diagram of a stepping motor control device according to a second embodiment; 4 is a configuration diagram of a torque/out-of-step estimating unit in FIG. 3; FIG. FIG. 11 is a configuration diagram of a stepping motor control device according to Example 3; FIG. 11 is a configuration diagram of a stepping motor control device according to a fourth embodiment;

Embodiments of the present invention will be described below with reference to the drawings. In addition, in each drawing, the same configurations are denoted by the same reference numerals, and detailed descriptions of overlapping portions are omitted. Moreover, each embodiment described below is not necessarily limited to the illustrated example.

Embodiment 1 A stepping motor controller and its control method according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 shows a configuration example of a stepping motor control device according to this embodiment.

The stepping motor 1 has windings of two or more phases and outputs a torque component due to the magnetic flux of a permanent magnet. FIG. 1 shows an example of a stepping motor having two-phase windings of A-phase and B-phase.

The driving driver 2 performs PWM (Pulse Width Modulation) control in the A-phase driver 2a and the B-phase driver 2b on the DC voltage E _DC which is the output of the DC voltage (power supply) 2c, and the A-phase and B-phase rectangular wave voltages are generated. to vary (control) the output voltage and rotation speed of the stepping motor 1 .

The A-phase voltage detector 3 detects the A-phase output voltage Vac of the stepping motor 1 .

The A-phase current detector 4 detects the A-phase output current Iac of the stepping motor 1 .

The B-phase voltage detector 5 detects the B-phase output voltage Vbc of the stepping motor 1 .

A B-phase current detector 6 detects a B-phase output current Ibc of the stepping motor 1 .

A phase command 7 outputs a phase command θ* that changes the angle of the stepping motor 1 .

The current command 8 outputs the peak value I* of the rectangular wave currents Iac and Ibc flowing through the stepping motor 1 .

The current command corrector 9 outputs the peak value I* of the rectangular wave currents Iac and Ibc as a second peak value I** according to the output torque estimated value τm̂.

The torque/out-of-step estimator 10 estimates the output torque τm of the stepping motor 1 from the A-phase voltage detection value Vac, the current detection value Iac, the B-phase voltage detection value Vbc, the current detection value Ibc, and the phase command θ ^* . ^ and the gate ON/OFF signal GA_on _/off are calculated and output.

Next, the basic operation (control method) of stepping motor control according to this embodiment will be described. In order to facilitate understanding of the control method according to the present invention, first, a case in which the configuration of the present invention (current command corrector 9 and torque/out-of-step estimator 10) is not applied will be described.

In the driving driver 2 composed of the A-phase driver 2a and the B-phase driver 2b, the current command 8 (I*) given from the upper layer is combined with the square-wave A-phase current detection value Iac and the B-phase current detection value Ibc. Current control is performed such that the peak values match, and the output voltage command value is PWM-controlled, so that the stepping motor 1 is applied with rectangular wave voltages Vac and Vbc.

In order to rotate the stepping motor 1, it is necessary to switch the current flowing through the windings in order. The rotational speed is the frequency at which the phases of the windings to be excited are switched. The relationship between the phase command 7 (θ*) and the angular frequency ω* is given by equation (1).

Here, P _m is the number of paired magnetic poles.

Further, by assuming in advance the maximum value of the load torque applied to the stepping motor 1 and setting the current command 8 (I*) according to the relationship of equation (2) so as to provide a margin for the maximum value _{τL_max} , , the stepping motor 1 is prevented from stepping out.

However, it is very difficult to set the current command 8 (I*) due to variations in the parts of each device driven by the stepping motor 1 and fluctuations in winding resistance due to temperature changes in the installation environment and operating conditions.

Also, if the current command 8 (I*) is set too large relative to the load torque, an over-excitation state will occur and the output torque will oscillate.

Therefore, in this embodiment, the current command corrector 9 and the torque/step-out estimator 10 are used to solve these problems.

The control method of this embodiment using these will be described below. FIG. 2 shows the configuration of the torque/out-of-step estimating section 10, which is a feature of the present invention, and the internal configuration thereof will be described.

A first-order lag filter 101 extracts the fundamental wave component of the A-phase voltage Vac and outputs a signal Vac_filter.

Reference numeral 102 denotes a first-order lag filter that extracts the fundamental wave component of the A-phase current Iac, and outputs a signal Iac_filter.

A first-order lag filter 103 extracts the fundamental wave component of the B-phase voltage Vbc and outputs a signal Vbc_filter.

A first-order lag filter 104 extracts the fundamental wave component of the B-phase current Ibc, and outputs a signal Ibc_filter.

Reference numeral 105 denotes a differential calculation unit for the phase command 7 (θ*), which outputs an angular velocity component ω*.

Here, 101 to 104 may be moving average filters for extracting fundamental wave components.

Reference numeral 106 denotes a torque estimating unit of the stepping motor 1, which detects the A-phase voltage detection value Vac_filter, the A-phase current detection value Iac_filter, the B-phase voltage detection value Vbc_filter, the B-phase current detection value Ibc_filter, and the angular velocity component ω. * is used to calculate the output torque estimate value τ _m ^ according to the equation (3).

Reference numeral 107 denotes a phase estimating unit of the stepping motor 1 , which detects the A-phase voltage detection value Vac_filter and the A-phase current detection value Iac_filter, the B-phase voltage detection value Vbc_filter and the B-phase current detection value Ibc_filter, and the stepping motor 1 . Using the set value R* of the winding resistance R, which is the circuit constant of , the electromotive voltage phase estimated value .theta.m which varies from 0 to 2.pi.

Reference numeral 108 denotes a period calculator, which calculates a period T, which is the reciprocal of ω*, according to Equation (5) using the angular velocity component ω*.

Reference numeral 109 denotes a step-out estimator, which measures the time Tn at which the electromotive voltage phase estimated value θ _m ̂ is 0, and calculates the current time Tn, the previous measurement time T(n−1), and the measurement time T(n−1) before the previous measurement. n−2), it is determined that the state is stable, and the gate ON/OFF signal G _{A_on/off} is set to 1.

In this embodiment, the current time Tn is changed to the previous measurement time T(n-1), and the previous measurement time T(n-1) is changed to the measurement time T(n-2) before the previous time, for each sampling period. In addition, the ratio between the measurement time and the period T is calculated sequentially by using the equation (6).

If the calculated ratios α(n−2), α(n−1), and α(n) are all near 1.0 [p.u.], it is determined that the state is stable, and the gate ON/OFF signal _{GA_on is} generated. Set _/off =1. Also, other than the above, it is determined as a step-out state, and the gate ON/OFF signal _{GA_on/off} =0 is set.

Here, step-out of the stepping motor 1 is estimated using three measurement times, but the concept is to estimate step-out when there is a large difference. You can have more.

The current command correction unit 9 uses the first current command I* and the output torque estimated value τ _m ^ to calculate the second current command I** according to Equation (7).

Here, K ₁ is a proportional gain, and when the load torque changes slowly, K ₁ should be set to about 1.05 to 1.1. Further, when the load torque changes rapidly, _K1 may be set to 1.1 or more. Loss of synchronism can be further prevented.

At this time, _K1 may be a value adjusted by actually driving the stepping motor 1 to move the apparatus. Also, if the timing at which the load torque suddenly changes is known in advance, _K1 may be changed to a large value before that timing, and _K1 may be changed to a small value after that timing.

With such a configuration, it is possible to prevent generation of motor torque _τm more than necessary, and to prevent torque oscillation due to overexcitation and loss of synchronism due to insufficient current.

Even when the stepping motor 1 is out of step in the worst case, the step out estimating unit 109 operates to detect the step out, cut off the gate signals of the A-phase driver 2a and the B-phase driver 2b, and stop the operation. be able to. In this case, _K1 may be intentionally changed significantly at the timing of restarting.

In this embodiment, the two operations of load torque estimation and out-of-step estimation are performed at the same time, but either one of them may be performed.

As described above, the stepping motor control device of this embodiment includes the driving driver 2 that controls the output voltage and rotation speed of the stepping motor 1, and the voltage detector (A-phase voltage detector) that detects the output voltage of the stepping motor 1. detector 3, B-phase voltage detector 5), a current detector for detecting the output current of the stepping motor 1 (A-phase current detector 4, B-phase current detector 6), and a voltage detector (A-phase voltage detector 3, voltage detection value detected by B-phase voltage detector 5), current detection value detected by current detectors (A-phase current detector 4, B-phase current detector 6), and speed information of stepping motor 1 (phase and a torque/step-out estimating unit 10 for estimating the output torque and electromotive voltage phase of the stepping motor 1 from the command θ* and the angular frequency ω ^* ). The driving of the stepping motor 1 is controlled based on the value and the electromotive voltage phase estimation value.

The torque/step-out estimator 10 also includes a first first-order lag filter 101 for extracting the fundamental wave component of the voltage detection value detected by the voltage detectors (the A-phase voltage detector 3 and the B-phase voltage detector 5). 103, second first-order lag filters 102 and 104 for extracting fundamental wave components of current detection values detected by the current detectors (A-phase current detector 4, B-phase current detector 6), and a first first-order lag filter. a torque estimator 106 that calculates an estimated output torque value from the output values of the filters 101 and 103, the output values of the second first-order lag filters 102 and 104, and speed information (phase command θ* and angular frequency ω*); Phase for calculating an electromotive voltage phase estimated value from the output values of the first-order lag filters 101 and 103, the output values of the second first-order lag filters 102 and 104, and the set value of the winding resistance that is the circuit constant of the stepping motor 104 an estimating unit 107; a period calculating unit 108 that calculates a period T that is the reciprocal of the speed information from the speed information (phase command θ* and angular frequency ω*); and a step-out estimating section 109 for setting the control signal _{GA_on/off} .

This enables low-cost, high-precision torque estimation and step-out estimation without the need for encoders or other position sensors or dedicated microprocessors, enabling highly efficient and highly reliable stepping motor drive control. becomes.

Here, a verification method when this embodiment is adopted (whether or not the present invention is implemented) will be described. A driver for driving a stepping motor has an A-phase voltage detector and a current detector, and a B-phase voltage detector and current detector (or at least one of the A-phase and B-phase voltage detectors and current detectors). Check if it exists on the driver circuit, change the load torque, and if the current peak value of the A-phase current detection value Iac or the B-phase current detection value Ibc changes in proportion to the load torque, this It is clear that the invention is adopted.

Embodiment 2 A stepping motor controller and its control method according to Embodiment 2 of the present invention will be described with reference to FIGS. 3 and 4. FIG. FIG. 3 shows a configuration example of a stepping motor control device according to this embodiment.

In the first embodiment, the output torque estimation value is calculated using the A-phase and B-phase voltage detection values and current detection values, but in the present embodiment, calculation is performed using only one of the A-phase and the B-phase. 3, reference numerals 1 to 9 are the same as those in FIG.

FIG. 4 shows the configuration of the torque/step-out estimating section 10', which is a feature of the present invention. Reference numerals 101-105 and 107-109 shown in FIG. A feature of this embodiment is that the torque estimation unit 106a shown in FIG. 4 instead of the torque estimation unit 106 shown in FIG. be.

By estimating the torque of either the A phase or the B phase and doubling the estimated output torque estimated value, the steady torque can be obtained with the same performance as the equation (3). is effective for simplification of

As described above, in the stepping motor control apparatus of the present embodiment, the torque/step-out estimating section 10′ estimates the output torque for one winding phase of the stepping motor 1, and the estimated output torque value is The output torque of the entire stepping motor 1 is estimated by multiplying by the number of winding phases of the stepping motor 1 .

Embodiment 3 A stepping motor controller and its control method according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 5 shows a configuration example of a stepping motor control device according to this embodiment.

This embodiment applies the present invention to a stepping motor drive system. In this embodiment, the change in the phase command 7 (.theta.*) (magnitude of the speed command) is automatically corrected according to the estimated output torque value .tau.m.sup.m. 5, reference numerals 1 to 10 are the same as those in FIG.

Here, when the estimated output torque τm is near the maximum torque _{TL_max} , the phase command correction unit 11 uses the first phase command θ* and the estimated output torque τm in accordance with equation (10) to obtain the second It is configured to calculate the phase command θ** of

In the stepping motor control device of this embodiment, the current set value of the drive driver 2 is automatically adjusted according to the output torque estimated value.

Here, K ₂ is a proportional gain, and when the load torque changes slowly, K ₂ should be set to about 0.95 to 0.9. Moreover, when the load torque changes rapidly, _K2 may be set to 0.9 or less. Even with such a configuration, the stepping motor can be prevented from stepping out.

A stepping motor controller and its control method according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 shows a configuration example of a stepping motor control device according to this embodiment.

In this embodiment, the operation (action) of the current command correcting section 9 and the phase command correcting section 11 is performed simultaneously in the stepping motor drive system. According to the output torque estimated value τ _m ^, the second current command I** is calculated based on equation (7), and the second phase command θ** is calculated based on equation (10).

If this embodiment is applied to a stepping motor controller, the stepping motor can be stably driven with a small current without stepping out.

Further, in the stepping motor control apparatus of the present embodiment, step-out of the stepping motor 1 is estimated from a change in the electromotive voltage phase estimated value. , the energization of the driver 2 is interrupted. Alternatively, when it is determined that there is a step-out, a step-out estimation signal is output, and the acceleration/deceleration rate of the phase command θ ^* given to the driver 2 is automatically adjusted according to the output torque estimate value or the step-out estimation signal.

The correction calculation of the phase command 7 and the current command 8 may be performed on a local area network (LAN) connected to a programmable logic controller (PLC) or a computer, which is a host device.

In the first to fourth embodiments described above, it is assumed that a general-purpose microprocessor is used, but a configuration using an analog circuit or an FPGA (Field Programmable Gate Array) may also be used.

Further, the stepping motor to which the present invention is applied is not limited to two phases, and may be five phases, for example.

Further, in Examples 1 to 4, the switching elements constituting the driving driver 2 may be Si (silicon) semiconductor elements or wide bandgap semiconductors such as SiC (silicon carbide) and GaN (gallium nitride). It may be an element.

In addition, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. A part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

DESCRIPTION OF SYMBOLS 1... Stepping motor 2... Drive driver 2a... A-phase driver 2b... B-phase driver 2c... DC voltage (power supply) 3... A-phase voltage detector 4... A-phase current detector 5... B-phase Voltage detector 6 B-phase current detector 7 Phase command 8 Current command 9 Current command corrector 10, 10' Torque/step-out estimator 11 Phase command corrector 101- 104 First-order lag filter 105 Differential calculator 106, 106a Torque estimator 107 Phase estimator 108 Period calculator 109 Step-out estimator θ ^* (first) phase command θ ^** ... (second) phase command, ω ^* ... angular frequency (angular velocity component), I ^* ... (first) current command, I ^** ... (second) current command, Vac... phase A ( A axis) voltage detection value, Iac... A phase (A axis) current detection value, Vbc... B phase (B axis) voltage detection value, Ibc... B phase (B axis) current detection value, τm^, τm^^... Output torque estimated value, θm̂: EMF phase estimated value, _{GA_on/off} : Gate ON/OFF signal.

Claims (10)

A stepping motor control device for controlling the driving of a stepping motor,
a drive driver that controls the output voltage and rotation speed of the stepping motor;
a voltage detector that detects the output voltage of the stepping motor;
a current detector that detects the output current of the stepping motor;
a torque/step-out estimating unit for estimating the output torque and electromotive voltage phase of the stepping motor from the voltage detection value detected by the voltage detector, the current detection value detected by the current detector, and speed information of the stepping motor; , and
The torque/step-out estimating unit includes a first first-order lag filter for extracting a fundamental wave component of the voltage detection value detected by the voltage detector;
a second first-order lag filter for extracting a fundamental wave component of the current detection value detected by the current detector;
a torque estimator that calculates an estimated output torque value from the output value of the first first-order lag filter, the output value of the second first-order lag filter, and the speed information;
a phase estimator that calculates an electromotive voltage phase estimation value from the output value of the first first-order lag filter, the output value of the second first-order lag filter, and the setting value of the winding resistance that is the circuit constant of the stepping motor; ,
a cycle calculator that calculates a cycle that is the reciprocal of the speed information from the speed information;
a step-out estimating unit that sets a control signal for the driving driver based on the electromotive voltage phase estimation value and the period;
A stepping motor control device for controlling driving of the stepping motor based on an output torque estimated value and an electromotive voltage phase estimated value estimated by the torque/step-out estimating section. A stepping motor control device for controlling the driving of a stepping motor,
a drive driver that controls the output voltage and rotation speed of the stepping motor;
a voltage detector that detects the output voltage of the stepping motor;
a current detector that detects the output current of the stepping motor;
a torque/step-out estimating unit for estimating the output torque and electromotive voltage phase of the stepping motor from the voltage detection value detected by the voltage detector, the current detection value detected by the current detector, and speed information of the stepping motor; , and
In the torque/out-of-step estimating section, the output torque for one winding phase of the stepping motor is estimated, and the estimated output torque estimated value is multiplied by the number of winding phases of the stepping motor to obtain the total output torque of the stepping motor. Estimate the output torque ,
A stepping motor control device for controlling driving of the stepping motor based on an output torque estimated value and an electromotive voltage phase estimated value estimated by the torque/step-out estimating section. The stepping motor control device according to claim 1 or 2 ,
A stepping motor controller for automatically adjusting a current set value of the driver in accordance with the output torque estimated value. The stepping motor control device according to claim 1 or 2 ,
estimating out-of-step of the stepping motor from a change in the electromotive voltage phase estimated value;
If it is determined that there is a step-out, output a signal for estimating the step-out,
A stepping motor control device, wherein power supply to the drive driver is interrupted according to the out-of-step estimation signal. The stepping motor control device according to claim 1 or 2 ,
estimating out-of-step of the stepping motor from a change in the electromotive voltage phase estimated value;
If it is determined that there is a step-out, output a signal for estimating the step-out,
A stepping motor control device that automatically adjusts an acceleration/deceleration rate of a phase command given to the driver in accordance with the output torque estimation value or the step-out estimation signal. A stepping motor control method for controlling driving of a stepping motor, comprising:
Detects the output voltage and output current of a stepping motor,
estimating an output torque and an electromotive voltage phase of the stepping motor from the detected voltage detection value and current detection value and speed information of the stepping motor;
extracting fundamental wave components of the voltage detection value and the current detection value;
calculating an estimated output torque value from the fundamental wave components of the extracted voltage detection value and current detection value and the speed information;
calculating an electromotive voltage phase estimation value from the fundamental wave component of the extracted voltage detection value and current detection value, and the setting value of the winding resistance, which is the circuit constant of the stepping motor;
calculating a cycle that is the reciprocal of the speed information from the speed information;
setting a control signal for a driver of the stepping motor based on the estimated electromotive voltage phase value and the period;
A stepping motor control method comprising: controlling driving of the stepping motor based on the estimated output torque estimated value and electromotive voltage phase estimated value. A stepping motor control method for controlling driving of a stepping motor, comprising:
Detects the output voltage and output current of a stepping motor,
estimating an output torque and an electromotive voltage phase of the stepping motor from the detected voltage detection value and current detection value and speed information of the stepping motor;
estimating an output torque for one winding phase of the stepping motor, and multiplying the estimated output torque estimated value by the number of winding phases of the stepping motor to estimate the output torque of the entire stepping motor ;
A stepping motor control method comprising: controlling driving of the stepping motor based on the estimated output torque estimated value and electromotive voltage phase estimated value . The stepping motor control method according to claim 6 or 7,
A stepping motor control method comprising: automatically adjusting a current set value of a driver of the stepping motor according to the output torque estimated value. The stepping motor control method according to claim 6 or 7,
estimating out-of-step of the stepping motor from a change in the electromotive voltage phase estimated value;
If it is determined that there is a step-out, output a signal for estimating the step-out,
A stepping motor control method comprising interrupting power supply to a driver of the stepping motor in accordance with the out-of-step estimation signal. The stepping motor control method according to claim 6 or 7,
estimating out-of-step of the stepping motor from a change in the electromotive voltage phase estimated value;
If it is determined that there is a step-out, output a signal for estimating the step-out,
A stepping motor control method comprising: automatically adjusting an acceleration/deceleration rate of a phase command given to a driver of the stepping motor according to the output torque estimated value or the step-out estimated signal.

Images