JP2972034B2 - Load torque measuring device for stepping motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load torque measuring device for a stepping motor, and more particularly to a load torque measuring device for a stepping motor capable of highly accurate and multifunctional actual load torque measurement in a mounted state of the motor.

[0002]

2. Description of the Related Art Stepping motors are applied to many industrial products such as OA equipment. Conventionally, there has been only an indirect evaluation method such as confirming a normal operation when a motor is driven at a voltage lower than a rated voltage as an evaluation method when performing a shipping inspection of these products. For this reason, when selecting a motor, it is necessary to select a large output with a large margin, which is not only economically wasteful, but also unnecessary torque injected excessively causes noise. There was an adverse effect. This is because there is no method for measuring the load torque required for the motor while the motor is mounted.

[0003]

As described above, conventionally,
With the stepping motor mounted, there is no effective means for measuring the load torque required for the motor. Therefore, an apparatus that measures the time of the load torque required in the operating state of the actual machine or the variation of the load torque as a function of the number of pulses applied to the motor is extremely useful. Also, when conducting tests on equipment equipped with a motor, under various conditions, collection / analysis of a large amount of data including fluctuations in load torque, operation of the print head during measurement, etc. If the influence can be measured, it is possible to take measures based on the analysis of the measurement result, and such a measuring device is desired. Further, in a stepping motor application product, a plurality of motors are used in many cases, and these motors are often operated synchronously. In such a case, an effective measuring device is expected to appear. Further, the characteristics of the motor vary depending on the operating temperature. For this reason, the appearance of a device capable of accurately measuring the load torque even when the temperature of the mounted motor is different from a predetermined value is expected.

It is an object of the present invention to provide a stepping motor capable of performing highly accurate and multifunctional actual load torque measurement in a mounted state of the motor.

[0005]

In order to solve the above-mentioned problems, a load torque measuring apparatus for a stepping motor according to the present invention provides a stepping motor obtained when a torque determined from a torque generating device is applied to the stepping motor to be tested. In the stepping motor load torque measuring device that determines the characteristic value of the current flowing through the stepping motor and measures the load torque acting on the stepping motor based on the relation data between the given torque and the characteristic value, the characteristic value is generated from the torque generating device. And adjusting means for adjusting the torque.

A load torque measuring device for a stepping motor according to another aspect of the present invention obtains a characteristic value of a current flowing through the stepping motor obtained when a torque determined from a torque generating device is applied to the stepping motor to be tested. In the stepping motor load torque measuring device that measures the load torque acting on the stepping motor based on the relationship data between the given torque and the characteristic value, the torque generated from the torque generating device is set to be smaller than a current value. When the setting is changed to a value, a means for rotating a motor to be measured connected to the torque generator is provided.

A load torque measuring device for a stepping motor according to another aspect of the present invention obtains a characteristic value of a current flowing through the stepping motor obtained when a torque determined from the torque generating device is applied to the stepping motor to be tested. In a load torque measuring device for a stepping motor for measuring a load torque acting on the stepping motor based on relation data between the given torque and the characteristic value, a display means for displaying the measurement result, and storing the measurement result. It is provided with a storage means, and a control means for controlling not to store in the storage means when changing the display mode setting of the display means.

A load torque measuring device for a stepping motor according to still another aspect of the present invention obtains a characteristic value of a current flowing through the stepping motor obtained when a torque determined from a torque generating device is applied to the stepping motor to be tested. A stepping motor load torque measuring device for measuring a load torque acting on the stepping motor based on the relation data between the given torque and the characteristic value, a display unit for displaying the measurement result, and storing the measurement result. Storage means for performing the measurement, and control means for controlling to store all the measured values prior to the display.

A load torque measuring device for a stepping motor according to another aspect of the present invention obtains a characteristic value of a current flowing through the stepping motor obtained when a torque determined from the torque generating device is applied to the stepping motor to be tested. In the stepping motor load torque measuring device for measuring the load torque acting on the stepping motor based on the relationship data between the given torque and the characteristic value, a clock having a frequency which is n times higher than a pulse for driving the stepping motor is used. It has a means for supplying to the outside.

A load torque measuring apparatus for a stepping motor according to still another aspect of the present invention obtains a characteristic value of a current flowing through the stepping motor obtained when a torque determined from a torque generating device is applied to the stepping motor to be tested. In the stepping motor load torque measuring device for measuring the load torque acting on the stepping motor based on the relation data between the given torque and the characteristic value, prior to the measurement, rotating the stepping motor to a predetermined position , And means for moving.

A load torque measuring device for a stepping motor according to another aspect of the present invention is connected to each of a plurality of stepping motors to be tested, and is obtained when a torque determined by a torque generator is applied to the stepping motor to be tested. A stepping motor load torque measuring device having a plurality of measuring devices for determining a characteristic value of a current flowing through the stepping motor and measuring a load torque acting on the stepping motor based on the relation data between the given torque and the characteristic value. Means for setting one of the plurality of measuring devices as a master device, setting the other as a slave device, outputting a signal indicating that the master device is in operation, and receiving the signal to operate the slave device. Means for automatically controlling the

A load torque measuring device for a stepping motor according to still another aspect of the present invention obtains a characteristic value of a current flowing through the stepping motor obtained when a torque determined from a torque generating device is applied to the stepping motor to be tested. A stepping motor load torque measuring device for measuring a load torque acting on the stepping motor based on relational data between the given torque and a characteristic value, wherein a current waveform characteristic flowing when a predetermined load torque is applied; Means for storing different frequencies, and means for changing the frequency for driving the stepping motor with time when measuring the load torque, wherein the measurement is performed according to the driving frequency. .

A load torque measuring device for a stepping motor according to still another aspect of the present invention obtains a characteristic value of a current flowing through the stepping motor obtained when a torque determined from the torque generating device is applied to the stepping motor to be tested. A load torque measuring device for a stepping motor for measuring a load torque acting on the stepping motor based on relation data between the given torque and a characteristic value, wherein the stepping motor is energized to increase the temperature of the stepping motor. Means, means for measuring a coil temperature of the stepping motor, and means for maintaining the coil temperature of the stepping motor at a predetermined temperature after reaching the predetermined temperature for a predetermined time. You.

[0014]

According to the present invention, in a stepping motor of the same type, when a predetermined load torque is applied, the characteristic of the current waveform flowing into the motor is uniquely determined. Measuring. A hysteresis brake can be applied as a means for applying a predetermined load torque to the motor. By providing a mechanism for externally driving a setting mechanism for applying the determined torque, and automatically controlling the mechanism from the control device side, the setting is performed to generate a required torque when needed.

In the known torque generator to which the above-mentioned hysteresis brake is applied, when the torque is reduced from a large set value to a small set value without rotating the load shaft, the generated torque with respect to the rotation angle of the load shaft becomes uniform. The phenomenon of disappearance (cogging phenomenon) occurs. This cogging phenomenon is prevented by rotating the motor to be measured while changing the torque setting.

Since the current waveform characteristics change depending on the motor temperature, it is necessary to perform calibration using the motor temperature as a parameter. It is easy to raise the coil temperature by energizing the coil of the motor, but more time is required until the temperature of the parts other than the coil settles to a desired value. As a countermeasure, after the coil temperature reaches a predetermined value, the temperature is maintained until a predetermined time elapses, and after the predetermined time elapses, calibration at the corresponding temperature is started.

In this way, the load torque can be measured in the mounted state, and a series of measured time-continuous data can be simultaneously displayed on the display device while being stored in the external storage device of the microcomputer. Make it possible. By storing the measured values, detailed analysis by a computer or the like can be performed later. At this time, if it is difficult to prioritize both storage and display due to a margin of processing speed or the like, either of them can be preferentially operated as necessary. Further, regarding the display, it is not always necessary to display all the data sequentially, and the data may be sampled temporally and executed.

When a motor to be measured is mounted and a systematic external force is applied to the mechanism during operation, a motor drive is performed to give a relationship between a timing at which the external force is applied and a timing at which a pulse is applied to the test motor. A service clock with the pulse multiplied by n is supplied to the outside. For example, in order to determine the initial position of the mechanism to be measured prior to the measurement in the case where the device to be measured reciprocates, a pulse having an arbitrary number of steps is first given to an arbitrary rotating direction of the motor to be measured. Means are provided.

In a device in which a plurality of stepping motors operate synchronously, a plurality of devices according to the present invention are used, one of which operates as a master device, and the other as a slave device, thereby improving efficiency. Enables measurement.

If calibration is performed in the required frequency range in advance, measurement can be performed even when the measurement frequency changes, such as when the motor to be measured is slowed up or slowed down.

[0021]

Next, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiment, an example will be described in which a mechanism driven by a stepping motor measures a change in load torque required of the motor. FIG. 1 is a basic overall configuration diagram showing one embodiment of a measuring device according to the present invention. Each winding (bifilar coil) ΦA, ΦA-, Φ of the stepping motor 1 (4 phase unipolar motor in this example)
B, .PHI.B- are connected at one end to an external power supply VM applied via a connector 5, and at the other end to switching transistors Q1, Q3, Q
2 and Q4 are connected. The pulse supply to each winding is controlled by operating the switching transistors Q1 to Q4 at a predetermined timing, and the excitation is switched. The switching transistors Q1 to Q4 constitute a drive circuit 7 for driving a stepping motor.

The controller 9 includes an oscillating circuit for generating a clock serving as a reference for the pulse supply timing to the winding, a positioning circuit for determining the rotation angle (position) of the stepping motor, and the like. It generates a clockwise rotation clock CCW, an excitation mode signal, and the like. The distribution circuit 8 receives the clock CLK and the excitation mode signal, and supplies a pulse in the 2-2 phase excitation to each winding.

First, the reference load torque generator 3 is coupled via a coupling 4 to the output shaft of a stepping motor 1 as a master motor, which is a non-defective motor whose motor specifications have been determined, to change the torque. At this time, the motor drive voltage, the motor drive frequency, the excitation mode, the coil excitation switching switching transistor, and the accompanying coil back electromotive force absorption circuit (not shown) are specified. The coil current also changes in response to the torque change. However, in order to measure the coil current, the current detection unit 10 (in this example, inserted into the winding ΦB- ) To detect the coil current iB-. This coil current iB-
Are amplified by the amplifier 11 and supplied to the feature extraction unit 13 via the terminal S1 of the switch 12. The feature extraction in the feature extraction unit 13 is, for example, to extract a feature of a torque-current waveform, and various information (parameters) are used as the feature. The basic torque measuring device as described above has already been proposed by the present inventors. For example, see Japanese Patent Application Nos. 3-272018 and 3-290856.

FIG. 2 shows a waveform of a current flowing into an arbitrary phase of the HB type stepping motor when the stepping motor is driven at a constant voltage by 2-2 phase excitation. At the point of time when the current starts flowing into the phase (the current-phase current input point) t0, the current shows a negative value. As time elapses, the current increases in the positive direction, and eventually shows a positive value. Thereafter, the current gradually increases. Here, when the load torque required for the motor is changed to 0, 1, 2, 3 Kg-cm as shown in the figure, the increasing tendency of the current changes. It can be seen that the current in the above section increases as the load torque increases. After the point in time when the current starts flowing into the other phase other than the phase of interest (other-phase current input point) t1, the increasing tendency of the current becomes complicated, and the current does not always increase as the torque increases.

As described above, when the current value is integrated in the section between t0 and t1 of the current in FIG. 2 and in which the current has a positive value, as shown in FIG. It can be seen that there is a smooth relationship with the load torque TQ. However, the above relationship is reproduced for motors having the same specification, but cannot be compared between motors having different specifications. Therefore, when mass production is to be performed using a large number of motors having the same specifications, the relationship between Q and TQ is calibrated once for a typical motor, and thereafter, the motor flows into the motor actually used in the actual machine. The load torque TQ can be measured by obtaining the Q from the current to be applied. As for the PM type motor, Q and TQ
Relationship can be determined.

FIG. 4 shows current waveforms when the drive voltage is sequentially changed to 13, 12, 11 V for the same motor as described above. It is clear from this that the current waveform characteristics become more remarkable when the drive voltage of the motor is reduced. However, if the voltage is lowered too much, the motor will step out and stop. Therefore, it can be seen that the motor should be driven with a voltage necessary and sufficient to generate the required load torque.
In reality, it is ideal to obtain a voltage at which the motor loses synchronism when a necessary maximum load torque is applied, and drive the motor at an optimum drive voltage (E0) having an appropriate margin. It has been found that the relationship between the current waveform characteristic Q and the load torque TQ, as well as the optimum drive voltage E0, varies depending on the drive frequency and operating temperature of the motor. Therefore, the calibration needs to be performed for a required range of frequency and temperature.

If necessary data is collected and stored in a file by the above-described calibration, the motor of the same specification mounted on the actual machine mechanism unit will be separated from the motor used for the calibration. The load torque required by the mechanism can be measured using the sensor as a sensor within the range of the manufacturing error of the motor.

As a means for applying a predetermined torque to the test motor, a reference torque generator shown in FIG. 5 can be used. As a torque generator, which is a means for applying a known torque, a perm torque manufactured by Kosin Lashin Co., Ltd. or the like can be used. This device uses a hysteresis magnetic material and applies a known torque to the rotating shaft by turning a dial indicating the mutual positional relationship between the fixed portion and the rotatable movable portion and setting the scale to a known value. It is. The torque generator 101 is attached to a support member 103 via a torque generator fixing section 102. The test motor 107 to be calibrated, which is fixed to the support member 106, and the shaft 105 of the coupling 1
04 to provide the required torque. The dial setting of the torque generator 101 is performed by rotation of a torque generator setting motor 111 which is attached to the support member 109 and is composed of a small stepping motor with a gear 110 and coupled by a coupling 108. Since the torque generator is configured as described above, the torque required for calibration can be automatically generated by giving an instruction pulse from the control device.

In the torque generator using the hysteresis brake, when the torque setting is changed from a large value to a small value without rotating the output shaft, the torque is uniform with respect to the rotation of the output shaft due to the residual magnetic effect. This causes a so-called cogging problem. In order to avoid this problem, in the present embodiment, when calibrating the test motor, while changing the torque setting of the torque generator in a direction to reduce it,
The test motor is rotated at an appropriate frequency. In this way, it is possible to dynamically measure the load torque required by the actual machine mechanism while using the motor as a load torque sensor while the motor is mounted on the actual machine.

FIG. 6 is a flowchart for operating the reference torque generator using the hysteresis brake shown in FIG. 5 to apply a known load torque to the test motor.
The scale of the reference torque generator can be converted into the number of pulses P to be supplied to the torque generator setting motor from when the reference torque generator is at the reference position. Therefore, a value P (TQ) of P required to generate a predetermined torque TQ is obtained (step S1). Assuming that a pulse of Pa has already been given to the setting motor at this time, the number of pulses PT required to move the motor to a predetermined position is obtained as an absolute value of (P-Pa) (step S2).

First, the direction of rotation of the setting motor is set to CW.
(Step S3), and based on the result of comparing P and Pa (Step S4), if P is smaller than Pa, the rotation direction is set again to CCW (Step S3).
5) In addition, after adding the correction amount PB of the backlash generated by the setting motor and the gear to the required pulse number PT (step S6), the test motor is rotated at an appropriate frequency to prevent the occurrence of the cogging described above. (Step S7). When the rotation direction of the setting motor is CW, there is no possibility of occurrence of cogging, and there is no need to rotate the test motor.

The rotation direction of the setting motor is CW or CC
After deciding on one of the W, when ready for that,
The setting motor is rotated (step S8). Wait for the PT pulse to be applied to the setting motor (step S
9), the rotation direction of the setting motor is determined (step S1).
0), if the rotation direction is not CCW, the setting motor is stopped and the setting operation is completed (step S16). When the rotation direction is CCW, as described above, the test motor is stopped (step S11), the rotation direction is set to CW (step S12), PB is set to PT (step S12), and PB is set to PT (step S13). Then, the setting motor is rotated (step S14). After the rotation of the RT pulse, the setting motor is stopped (step S16). At this time, it is necessary to rotate the setting motor in the CW direction in order to return by the backlash correction amount PB. When the setting motor is rotated in the CW direction, there is no risk of occurrence of cogging, and thus the test motor may be stopped. Further, as the reference torque generator, in addition to the hysteresis brake, it is of course possible to use a powder brake type torque generator with a torque sensor of Biblack, USA, as long as it can generate accurate torque. .

Next, an embodiment in which the measuring apparatus according to the present invention is realized as a system using a microcomputer will be described in detail. FIG. 7 shows an embodiment of the above system. Microcomputer (CPU) 2 on bus BUS
13, a ROM 212, and a RAM 211 are arranged in the same manner as in a normal system. Also, the LCD / software switch drive unit 215 is controlled via an appropriate interface I / F 217 to drive the LCD / software switch unit 214 and the interface I / F
A keyboard 216 is connected via 218 to constitute a man-machine interface. Thus, input of measurement conditions, instructions from the apparatus side, and display of measurement results are performed. Further, the GP-IB interface unit 222 or R
Data can be exchanged with an external computer (personal computer) via the S232C interface 223. Further, the bus has an FDD for controlling the FDD 221.
The DD control unit 220 is connected, and the external interface 219 is connected.

Drive pulse generator 20 arranged on bus
From 6, a drive timing to the motor to be measured 200 is generated according to an instruction from the CPU 213. The driving circuit 201 for the unipolar motor or the driving circuit 202 for the bipolar motor is selectively used as necessary. The drive circuit receives power supply from the voltage variable power supply 205 and can be configured by transistors Q1 to Q4 and the like as in the example shown in FIG. The motor to be measured 20
0 is driven. In the drive circuit, as in the case of FIG. 1,
A current / voltage detecting means 207 using a resistor or the like is provided.
The instantaneous value of the detected current is converted into a digital value by an A / D converter at an appropriate sampling interval.
Under the control of the MA control unit 208, the data is sequentially stored in the RAM 211. The sampling is executed by starting A / D conversion in accordance with an instruction from a trigger generator arranged on the bus. Further, the trigger generator receives a synchronization pulse from the pulse generator in order to synchronize the timing of the sampling generated by the trigger generator with the timing of the motor drive pulse.

Prior to the measurement, the reference torque setting device control section 209 is controlled under the control of the CPU 213, and the driving circuit 204 drives the reference torque setting device 203.
In this embodiment, it is necessary to appropriately set the drive voltage of the motor to be measured in order to make the characteristics of the current waveform remarkable with respect to the fluctuation of the load torque. For this reason, an appropriately set voltage is supplied to the drive circuit from the voltage variable power supply 205 arranged on the bus.

FIG. 8 shows how the load torque varies with the rotation of the motor. (A) shows an example where the setting is inappropriate. By appropriately changing the setting of the scale indicating the torque on the screen, the screen can be set to an appropriate state as shown in FIG. By the way, in the stepping motor load torque measuring device of the present invention,
The load torque of the actual machine on which the motor is mounted can be dynamically measured. Therefore, if the measurement result is stored in a file, it can be analyzed later by a computer. When the measurement data is filed according to this purpose, it is desirable to sequentially file all data obtained at each measurement point.

When measuring the dynamic characteristics of the torque of the mechanism using a stepping motor of a type operating at a high frequency, simultaneously displaying the screen while creating the measurement file is a matter of processing speed. May not always be easy. In such a case, by changing the priority of the file creation operation and the display operation as needed, it becomes possible to supply a more easy-to-use measuring device.

When the screen settings shown in FIG. 8 are changed, for example, when an oscilloscope is used, the screen settings are first made so that the display is appropriately set to perform the measurement. It is common practice not to change the screen settings after the actual measurement. However, during the measurement, pay attention to the displayed data. In order to change the screen settings, the CPU requires a considerable processing time. Therefore, while the screen setting is being changed, there is no room to reliably store the measurement data in the external storage device.

Similarly, the setting change of the screen shown in FIG. 8 has a strong meaning of adjusting the screen prior to the measurement. Therefore, at this point, it is important to display the measurement data in accordance with the settings on the screen. On the other hand, it is not always necessary to store the measurement data in the external storage device. Conversely, after completing the screen setting and starting the measurement, it is important to reliably store the measured data in the external storage device as described above. At this time, it is usually unnecessary to change the screen settings.

In consideration of the above, the measuring device according to the present embodiment does not store the measurement data in the external storage device when the screen is set, but stores the measurement data in the external storage device. , The screen is not set.

FIG. 9 is a flowchart for setting a screen for displaying a measurement result, storing the measurement result in an external storage device, and performing control of giving priority to storing the measurement result in the storage device over the screen display. I have. The screen and the measurement conditions are initialized (steps S21 and S22), and further the initialization for writing to the external storage device is performed (step S2).
3) When the initialization is completed, the process waits until the start button is pressed (step S24). After the start button is pressed, the test motor starts rotating (step S2).
5). Thereafter, every time the torque is measured from the test motor (step S26), the save mode (mode for storing the measured data in the external storage device) is determined (step S2).
7) If the mode is not the save mode, the save is not executed, and the screen is set if necessary. At this time, the setting condition change is determined (step S33).
If there is any change, the setting is changed (step S34), and the process proceeds to step S29.

In the save mode, the measurement data is stored in the external storage device (step S28), but the screen is not set. Here, if the drawing started last time is completed, the drawing start of the data measured this time is instructed (steps S29 and S30). If the previous data is being drawn, the current data is not drawn. The above operation is continued until the stop button is pressed (step S31). Thereafter, when the stop button is pressed, the test motor is stopped and the measurement is terminated (step S3).
2).

As described above, even when the data speed is high, when storing the measured data in the external storage device, it is necessary to store all of the measured data. Conversely, even if all measurement data is displayed on the screen, it is difficult to see all the data if the drawing speed is high. Therefore, in this embodiment, when the data speed is particularly high and it is difficult to achieve both the storage of the measurement data and the drawing on the screen, the storage operation of the measurement data to the external storage device is prioritized. In addition, drawing on the display device is performed in a sampling format, that is, drawing can be performed by thinning out data in the middle.

FIG. 10 shows how a systematic disturbance occurs while the motor to be measured is rotating, and the load torque required for the test motor fluctuates accordingly. In the embodiment shown in FIG. 10, the timing at which the disturbance is applied is indicated by the phase relationship with the drive pulse of the motor to be measured.

As a specific example, consider the relationship between the paper feed in a facsimile and the printing timing due to the current flowing into the print head. It is assumed that the test motor (paper feed motor) is driven at the timing shown in FIG. As a result, the position of the recording paper changes over time as shown in FIG. Here, as shown in (d), when a current is supplied to the print head in synchronization with the drive clock of the motor,
As shown in (e), the motor must bear both the torque required to feed the recording paper and the torque generated by the print head and the recording paper sticking to each other because printing has been performed. Requires large torque.

Therefore, as shown in (d '), the printing timing is slightly delayed from the motor driving timing. Then, printing is performed after the recording paper starts moving, so the torque required for both is dispersed in time,
It can be seen that the torque required for the motor decreases as shown in (e ').

In order to enable the above-described control of the printing timing, the measuring apparatus according to the present embodiment uses the pulse multiplied by n of the driving pulse (b) of the test motor as the service clock as shown in FIG. To the outside of the The external device can finely control the timing of printing with respect to the drive pulse by using the motor drive pulse as a reference and using the n-multiplied pulse.

FIG. 11 shows an embodiment for generating the above-mentioned n-multiplied pulse. The source oscillator 201 generates a frequency clock that is 1 / n times the frequency required to drive the motor. This clock is supplied to an external device as an n-multiplied clock. This is divided by the frequency divider 202 into 1 / n, and the divided signal is supplied to the motor drive pulse generator 203 in FIG.
It is supplied as a clock as shown in FIG.

The load torque measuring apparatus according to the present embodiment can be applied to a case where the motor to be measured continuously rotates in a fixed direction, or a case where the motor is rotated in a reverse direction after rotating a fixed number of pulses. There are various cases. Therefore, in some cases, it is necessary to move the device to be measured to the origin before starting the measurement. In such a case, in the apparatus of this embodiment, the initial position of the test apparatus can be determined by rotating the test motor in response to a manual operation instruction.

FIG. 12 shows a flowchart for moving the mechanism to be measured to a predetermined position (starting the initial position) before starting the measurement. First, the drive frequency of the test motor is initialized to the frequency f0 for positioning (step S4).
1). Next, the drive voltage is initialized to a value at the frequency f0 (step S42). Until the start button is pressed and the measurement is started, the mechanism to be measured
It is monitored that each button for rotating in the direction or the CCW direction is pressed (steps S43 and S4).
5). If the button for instructing rotation in the CW direction is pressed, the motor to be measured is rotated in the CW direction (step S44). If a button for instructing the motor to be measured to rotate in the CCW direction is pressed,
It is rotated in the W direction (step S46). By repeating the above operation as necessary, the initial positioning of the mechanism to be measured is completed.

When the initial position is completed, the preparation for measurement is completed, and the start button is pressed (step S4).
7) The measurement is started. At the time of measurement, the drive frequency of the motor to be measured is set to the measurement frequency fM (step S4).
8) Apply the optimal drive voltage according to fM (not shown), and continue measuring and displaying the load torque while rotating the test motor until the stop button is pressed. (Steps S49, S50, S51 and S52). When the stop button is pressed, the motor is stopped (step S5).
3), end the measurement.

When a plurality of the same type or different types of stepping motors are used in the same device, the load torque applied to the plurality of motors is measured simultaneously by using a plurality of load torque measuring devices according to the present invention. In some cases. A master / slave function is added to the load torque measuring device of the present embodiment to enable efficient measurement. The measuring device designated as the master device performs the measuring operation as usual, but turns on the GO signal during the measurement. The measurement device designated to perform the slave operation performs the measurement while the GO signal from the master unit indicates a “true” value. In this way, it is possible to simultaneously observe the behavior of the load torque characteristics of a plurality of motors having relevance to each other by using a plurality of load torque measurement devices.

FIG. 13 is a flow chart of the above embodiment in which a plurality of load torque measuring devices according to the present embodiment are operated in conjunction with each other, and the measurement of a device to be measured using a plurality of stepping motors in conjunction with each other is performed. The left side of the figure shows the operation of the master unit, and the right side shows the operation of the slave unit linked with the master unit according to the instruction of the master unit. First, both the master unit and the slave units are initialized to start measurement (steps S61 and S71). In the master unit, the value of the signal GO instructing the start / continuation of the operation from the master unit to the slave unit is cleared (step S62), so that the slave unit waits for the GO signal from the master unit.
It has stopped (step S72).

When the start button of the master unit is pressed (step S63), the GO signal is set to true (step S64), and the motor to be measured connected to the master unit starts rotating (step S65). When the GO signal of the master unit becomes true (step S72), the slave unit starts operation, and starts rotating the motor to be measured connected to the slave unit (step S73). Thereafter, in the master unit, the load torque is measured and displayed until the stop button is pressed (steps S66 and S67).
During this time, the GO signal remains true. As long as the GO signal is true, the slave units, like the master unit,
Continue the load torque measurement and display (Steps S74 and S7)
5).

When the master machine determines that the stop button has been pressed (step S68), it sets the GO signal to false (step S69), stops the motor to be measured (step S70), and ends the measurement. I do. It is detected that the GO signal of the master unit has become false (step S7).
6), and also stop the motor of the slave unit (step S7).
7) Terminate the measurement. In this way, the master device and the slave device are linked, and the operation of the device having a plurality of motors can be synchronized and measured. In the above description, an example in which only one slave unit is used has been described, but it is apparent that even if there are a plurality of slave units, control can be performed without contradiction.

As is well known, when the stepping motor is rotated at a high speed, the stepping motor is once rotated at a frequency lower than the final frequency (self-starting) and then gradually increased toward the target frequency. Such a method is called slow start or slow up. Conversely, when the motor rotating at high speed is decelerated or stopped, the operation reverse to the above may be performed. This is called slow down. It is necessary to measure the load torque required for the motor to be measured while the motor to be measured is performing a slow-up or slow-down operation.

As described above, the load torque can be measured from the relationship between the magnitude TQ of the load torque applied to the stepping motor and the characteristic Q of the current waveform flowing into the motor at this time. The relationship between TQ and Q changes depending on the magnitude of the motor driving voltage and the driving frequency. Therefore, when performing calibration, the optimum driving voltage is obtained within the necessary range of the driving frequency, and when the motor is driven at the optimum driving voltage, TQ is set using the frequency as a parameter.
And the relationship between Q and Q.

In order to measure the magnitude of the load torque applied to the motor during slow-up or slow-down in the state prepared as described above, an instantaneous frequency is detected, and an optimum motor suitable for the frequency is detected. A drive voltage is applied instantaneously and Q is measured. Then, the torque is measured from the relationship between TQ and Q using the frequency as a parameter.

FIG. 14 shows a flowchart for measuring the load torque of the motor to be measured including the slow-up process. In this example, for the sake of simplicity, the description of the slow down process is omitted, but is the same as the slow up process. First, after the display condition and the measurement condition are initialized (steps S81 and S82), the process waits until the start button is pressed (step S83). When the button is pressed, the frequency f for driving the motor to be measured is changed to the self-starting frequency f.
Initialized to 1 (step S84). After that, the slow-up sequence is started.

Until the driving frequency f reaches the final frequency fh, f is increased by a small amount Δf (slow-up).
(Steps S85 and S86). When the maximum value fh is reached,
Thereafter, the rotation continues at the frequency fh. Once the drive frequency f of the motor to be measured is determined, the optimum drive voltage E0
Is applied to the motor (step S87), and the motor is rotated (step S88). The load torque of the rotating motor is measured by comparing the pre-calibrated load torque TQ of the motor to be measured with the characteristic of the current waveform characteristic Q at the corresponding drive frequency (step S89) and displayed (step S90). ). Next, before increasing the frequency f by Δf, the process waits for a short time Δt (step S91). Accordingly, the motor to be measured continues the slow-up sequence according to the gradient determined by Δf / Δt until it is determined in step S92 that the measurement has been completed, and ends the measurement.

The relationship between the load torque TQ and the current waveform characteristic Q depends not only on the aforementioned parameters but also on the motor temperature. FIG. 15 shows that the motor temperature of the PM type motor is 25.
It is an example which shows the difference of the characteristic of the motor at the time of ゜ C and 48 ° C. Accordingly, when it is necessary to measure the load torque at a special temperature, it is necessary to calibrate the relationship between TQ and Q at the corresponding temperature.

The temperature of the stepping motor can be easily increased by continuously supplying a relatively large current to the coil. However, the temperature of the motor is directly increased by this operation. Also, the temperature of the coil of the motor can be easily measured by using the resistance method.

Therefore, the temperature of the motor can be increased to a value to be calibrated by continuously supplying the current to the coil of the motor. When the coil reaches a predetermined temperature, the temperature of the other parts of the motor is still lower than the temperature of the coil. In particular, the characteristics of the magnet arranged on the rotor of the motor greatly change with temperature. Therefore, it is necessary to bring the temperature of the entire motor including the magnet to a predetermined value before starting the calibration. In reality, it is not easy to measure and manage the temperature of each part of the motor other than the coil. Therefore, as a practical process generally performed, when evaluating the characteristics of a motor, a method of starting measurement after a predetermined time has elapsed after the motor temperature has become constant is applied mutatis mutandis.

FIG. 16 shows a heating process until calibration at a specific temperature is started. When energization of the motor coil is started, the coil temperature starts to rise, and reaches a predetermined temperature T after a time tr. Thereafter, the coil current is controlled so as to maintain the temperature T. Thereafter, the state maintained at the temperature T is maintained for a predetermined time th. As a result, even if the motor is maintained at a predetermined temperature, it can be regarded as a practically useless state. When the time th has elapsed, calibration at the corresponding temperature is started.

FIG. 17 is a flowchart showing a process of increasing the temperature of the motor to a predetermined temperature when the motor is calibrated at an arbitrary temperature, and a flowchart for performing the calibration after maintaining the temperature at the reached temperature for a predetermined time. First, after the calibration conditions are set (step S101), the temperature of the motor that is not energized is measured by a thermistor or other means, the resistance value of the motor coil at that temperature is measured, and the coil temperature and coil resistance are measured. (Step S102).

When the preparation is completed, the temperature of the motor is started.
An electric current is applied to the stationary motor (step S103),
Increase coil temperature. At this time, the coil temperature TP is
By measuring the coil resistance, the above-mentioned coil resistance /
It is measured from the relationship between the coil temperatures (steps S104 and S105). In step S106, energization of the coil is continued until it is determined that the coil temperature TP has reached the predetermined temperature TP0. When the coil temperature reaches the predetermined value TP0, the timer t for measuring the holding time is cleared (step S1).
07). Thereafter, the coil resistance is measured (step S10).
8) From this, the coil temperature TP is determined (step S10).
9), TP and TP0 are maintained such that TP maintains a predetermined temperature TP0.
The current flowing through the coil is turned on or off depending on the magnitude relation of (steps S110, S111 and S11).
2). When the state in which the temperature of the coil is maintained at the predetermined value TP0 continues for a predetermined holding time th, a calibration sequence is started (steps S113 and S114).

[0067]

As described above, according to the load torque measuring device for a stepping motor according to the present invention, it is necessary to use the motor itself as a load torque sensor and the actual machine mechanism while the motor is mounted on the actual machine. Since the applied load torque can be dynamically measured, the industrial application value is extremely high.

[Brief description of the drawings]

FIG. 1 is a basic overall configuration diagram showing one embodiment of a measuring device according to the present invention.

FIG. 2 is a diagram showing a current waveform flowing into an arbitrary phase of an HB type stepping motor when the stepping motor is driven at a constant voltage by 2-2 phase excitation.

FIG. 3 is a diagram showing a relationship between an integral value Q and a load torque TQ.

FIG. 4 is a diagram showing a current waveform when a drive voltage is sequentially changed like 13, 12, 11V.

FIG. 5 is a diagram illustrating a configuration of a reference torque generator that applies a predetermined torque to a test motor.

6 is a flowchart for operating a reference torque generator using a hysteresis brake shown in FIG. 5 to apply a known load torque to a test motor.

FIG. 7 is a diagram showing an example of a configuration system according to the present invention.

FIG. 8 is a view showing another embodiment of the present invention and showing a state in which a load torque fluctuates with rotation of a motor.

FIG. 9 shows a screen setting for displaying a measurement result according to the embodiment of the present invention, and stores the measurement result in an external storage device;
9 is a flowchart illustrating control for giving priority to storage of measurement results in a storage device over screen display.

FIG. 10 is a diagram showing a state in which a systematic disturbance occurs while the motor to be measured in the embodiment of the present invention is rotating, and the load torque required for the test motor fluctuates accordingly.

11 is a diagram showing an embodiment for generating an n-multiplied pulse in the embodiment in FIG.

FIG. 12 is a flowchart for moving a mechanism to be measured to a predetermined position (initial position determination) prior to the start of measurement in the embodiment of the present invention.

FIG. 13 is a flowchart of an embodiment in which a plurality of load torque measuring devices of the present invention are operated in conjunction with each other, and measurement is performed on a device to be measured using a plurality of stepping motors in conjunction with each other.

FIG. 14 is a view showing a flowchart for measuring a load torque of a motor to be measured including a slow-up stroke in the embodiment of the present invention.

FIG. 15 shows a motor temperature of 25 ° C. for a PM type motor.
FIG. 9 is a diagram showing a difference between the characteristics of the motor when the temperature is at 48 ° C. and FIG.

FIG. 16 is a diagram showing a heating process until calibration at a specific temperature is started.

FIG. 17 is a flowchart showing a process of raising the temperature of a motor to a predetermined temperature when the motor is calibrated at an arbitrary temperature, and subsequently performing the calibration after maintaining the temperature at the reached temperature for a predetermined time.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Stepping motor 2 Actual machine mechanism 3
Reference load torque generator 4 Coupling 5, 6
Connector 7 Drive circuit 8
Distribution circuit 9 Controller 10
Current detector 11 Amplifier 12
Switches 13 and 15 Feature extraction unit 14
Reference value memory 16 Measurement value memory 17
Collation judgment unit 18 Display 19
Printer

Continuation of front page (56) References JP-A-6-43049 (JP, A) JP-A-2-155496 (JP, A) JP-A-3-150087 (JP, A) JP-A-2-60496 (JP) JP-A-55-71196 (JP, A) JP-A-56-166439 (JP, A) JP-A-1-3111885 (JP, A) JP-A-63-31497 (JP, A) 4-312398 (JP, A) JP-A-3-78483 (JP, A) JP-A-2-51386 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01L 5/00 H02P 8/34

Claims (9)

(57) [Claims] 1. A characteristic value of a current flowing through a stepping motor obtained when a torque determined from a torque generating device is applied to the stepping motor to be tested is obtained, and based on relation data between the given torque and the characteristic value. A load torque measuring device for a stepping motor for measuring a load torque acting on the stepping motor, comprising an adjusting means for adjusting a torque generated from the torque generating device. . 2. A characteristic value of a current flowing through a stepping motor to be obtained when a torque determined from a torque generating device is applied to the stepping motor to be tested is obtained, and based on relational data between the given torque and the characteristic value. In the stepping motor load torque measuring device that measures the load torque acting on the stepping motor, the torque generated by the torque generating device is connected to the torque generator when the setting is changed from a current value to a smaller value. And a means for rotating the motor to be measured. 3. A characteristic value of a current flowing through the stepping motor obtained when a torque determined from the torque generating device is applied to the stepping motor to be tested is obtained, and based on relational data between the given torque and the characteristic value. A load torque measuring device for a stepping motor for measuring a load torque acting on the stepping motor, wherein a display means for displaying the measurement result, a storage means for storing the measurement result, and a display mode setting of the display means are changed. And control means for controlling so as not to store the data in the storage means. 4. A characteristic value of a current flowing through the stepping motor obtained when the torque generated from the torque generating device is applied to the stepping motor to be tested is determined, and based on relation data between the given torque and the characteristic value. In a stepping motor load torque measuring device that measures a load torque acting on the stepping motor, a display unit that displays the measurement result; a storage unit that stores the measurement result; Control means for controlling so as to store all measured values. A load torque measuring apparatus for a stepping motor, comprising: 5. A characteristic value of a current flowing through the stepping motor, which is obtained when a torque determined by the torque generating device is applied to the stepping motor to be tested, is determined based on relation data between the given torque and the characteristic value. A load torque measuring device for a stepping motor for measuring a load torque acting on the stepping motor, comprising: means for externally supplying a clock having a frequency which is n times higher than a pulse for driving the stepping motor. Load torque measuring device. 6. A characteristic value of a current flowing through a stepping motor to be obtained when a torque determined by a torque generating device is applied to the stepping motor to be tested, and based on relation data between the given torque and the characteristic value. A load torque measuring device for a stepping motor for measuring a load torque acting on the stepping motor, comprising: a step for rotating and moving the stepping motor to a predetermined position prior to the measurement. Torque measuring device. 7. A characteristic value of a current which is connected to each of the plurality of stepping motors to be tested and which is obtained when a torque determined from a torque generator is applied to the stepping motor to be tested and which is obtained, is obtained. A stepping motor load torque measuring device having a plurality of measuring devices for measuring the load torque acting on the stepping motor based on the relationship data between the obtained torque and the characteristic value, wherein one of the plurality of measuring devices is a master machine And a means for outputting a signal indicating that the master device is operating, and a means for automatically controlling the operation of the slave device in response to the signal. A load torque measuring device for a stepping motor. 8. A characteristic value of a current flowing through the stepping motor, which is obtained when a torque determined from the torque generating device is applied to the stepping motor to be tested, is determined, and based on relation data between the given torque and the characteristic value. A load torque measuring device for a stepping motor for measuring a load torque acting on the stepping motor, wherein a means for storing a current waveform characteristic flowing when a predetermined load torque is given for different frequencies; Means for changing the driving frequency of the stepping motor with time, and performing the measurement according to the driving frequency. 9. A characteristic value of a current flowing through the stepping motor obtained when a torque determined from the torque generating device is applied to the stepping motor to be tested is obtained, and based on relationship data between the given torque and the characteristic value. A stepping motor load torque measuring device for measuring a load torque acting on the stepping motor, comprising: means for energizing the stepping motor to increase the temperature of the stepping motor; and means for measuring a coil temperature of the stepping motor. Means for maintaining the coil temperature of the stepping motor at a predetermined temperature after the coil temperature has reached a predetermined temperature, for a predetermined period of time, the load torque measuring device for a stepping motor.