JPH0626953A - Load torque measuring device for stepping motor - Google Patents

Abstract

PURPOSE:To provide a stepping motor capable of precise and multifunctional measurement of actual load torque in a motor mounting state. CONSTITUTION:A load torque measuring device for stepping motor which determines the characteristic value of the current carried to a stepping motor to be tested obtained when a determined torque is given from a torque generating device to the stepping motor, and measures the load torque acting on the stepping motor on the basis of the relational data between the given torque and the characteristic value has a regulating means for regulating the torque generated from the torque generating device and a means for rotating the motor to be tested when the torque from the torque generating device is changed from the present value to a smaller value.

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 which enables highly accurate and multifunctional actual load torque measurement in a motor mounted state.

[0002]

2. Description of the Related Art Stepping motors are applied to many industrial products such as office automation equipment. Conventionally, as an evaluation method at the time of shipping inspection of these products, there is only an indirect evaluation method such as confirming a normal operation when the motor is driven at a voltage lower than the rated voltage. Therefore, when selecting a motor, there is no choice but to select a high-output one with a large margin, which is not only economically wasteful, but also unnecessary torque injected excessively causes noise. There was a bad effect of. This is because there is no method for measuring the load torque required for the motor with the motor mounted.

[0003]

As described above, as described above,
There was no effective means to measure the load torque required for the motor with the stepping motor mounted. Therefore, a device that measures the load torque time required in the operating condition of a real machine, or the variation of the load torque as a function of the number of pulses applied to the motor is extremely useful. In addition, when testing a device equipped with a motor, under various conditions, a large amount of data including fluctuations in load torque is collected / analyzed, the print head operates during measurement, and other disturbances applied to the system under test. If the influence can be measured, it becomes 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 often used, and these motors are often moved in synchronization, and it is expected that an effective measuring device will appear even in such a case. Further, the characteristics of the motor differ 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 also desired.

Therefore, an object of the present invention is to provide a stepping motor which enables highly accurate and multifunctional actual load torque measurement in a motor mounted state.

[0005]

In order to solve the above-mentioned problems, a load torque measuring device for a stepping motor according to the present invention is obtained when a torque determined by a torque generator is applied to a stepping motor under test. In a load torque measuring device for a stepping motor for determining a characteristic value of a current flowing through the load torque measuring device, the load torque acting on the stepping motor based on the relational data between the given torque and the characteristic value is generated from the torque generating device. It is configured to include an adjusting unit that adjusts the torque.

A load torque measuring apparatus 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 by the torque generating apparatus is applied to the stepping motor under test, In a load torque measuring device for a stepping motor, which measures a load torque acting on the stepping motor based on the relational data between the given torque and a characteristic value, a torque generated from the torque generating device is smaller than a current value. When the setting is changed to a value, it is configured to rotate the motor to be measured connected to the torque generator.

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 by the torque generating device is applied to the stepping motor under test, In a load torque measuring device for a stepping motor, which measures a load torque acting on the stepping motor based on the relational data between the given torque and a characteristic value, display means for displaying the measurement result, and the measurement result is stored. It is configured to include a storage unit and a control unit that controls so as not to store in the storage unit when changing the display mode setting of the display unit.

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 by the torque generating device is applied to the stepping motor under test. A load torque measuring device for a stepping motor, which measures a load torque acting on the stepping motor based on the relational data between the given torque and a characteristic value, display means for displaying the measurement result, and storing the measurement result. And a control means for performing control so that all the measured values are stored prior to the display during the measurement.

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 by the torque generating device is applied to the stepping motor under test, In a load torque measuring device for a stepping motor, which measures a load torque acting on the stepping motor based on the relational data between the given torque and a characteristic value, a clock having a frequency n times as high as a pulse for driving the stepping motor is used. It is configured to have means for supplying it to the outside.

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 by the torque generating device is applied to the stepping motor under test. In a stepping motor load torque measuring device for measuring a load torque acting on the stepping motor based on the relational data between the given torque and the characteristic value, the stepping motor is rotated to a predetermined position prior to the measurement. , And has 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 under test, and is obtained when a torque determined by the torque generator is applied to the stepping motor under test. A load torque measuring device for a stepping motor having a plurality of measuring devices for obtaining a characteristic value of a current flowing through the stepping motor and measuring a load torque acting on the stepping motor based on the relational data between the given torque and the characteristic value. A means for outputting one of the plurality of measuring devices as a master machine and another as a slave machine for outputting a signal indicating that the master machine is in operation, and an operation of the slave machine by receiving the signal. And means for automatically controlling the.

A stepping motor load torque measuring apparatus 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 by the torque generating apparatus is applied to the stepping motor under test. In a load torque measuring device for a stepping motor, which measures a load torque acting on the stepping motor based on relational data between the given torque and a characteristic value, a current waveform characteristic flowing in when a predetermined load torque is given And means for storing different frequencies and means for changing the frequency for driving the stepping motor with time when measuring the load torque, and configured to perform the measurement 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 by the torque generating device is applied to the stepping motor under test. In a stepping motor load torque measuring device for measuring a load torque acting on the stepping motor based on the relational data between the given torque and the characteristic value, the temperature of the stepping motor is raised by energizing the stepping motor. Means, means for measuring the coil temperature of the stepping motor, and means for maintaining the temperature of the stepping motor for a predetermined time after the coil temperature of the stepping motor reaches a predetermined temperature. It

[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 to utilize the load torque. I'm measuring. A hysteresis brake can be applied as a means for applying a predetermined load torque to the motor. A mechanism for externally driving the setting mechanism that gives the determined torque is provided, and by automatically controlling this from the control device side, the setting is performed so as to generate a torque of a necessary magnitude when necessary.

In the known torque generator to which the hysteresis brake is applied, if the torque is lowered 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 disappearing (cogging phenomenon) occurs. This cogging phenomenon is prevented by rotating the motor under measurement while changing the torque setting.

Since the characteristics of the current waveform change depending on the temperature of the motor, it is necessary to calibrate the temperature of the motor as a parameter. It is easy to raise the coil temperature by energizing the coil of the motor, but it takes more time until the temperature of the portion other than the coil reaches a desired value. As a countermeasure against this, after the temperature of the coil 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 in the mounted state can be measured, and a series of measured time continuous data can be stored in the external storage device of the microcomputer and simultaneously displayed on the display device. It is possible. By storing the measured values, detailed analysis by a computer or the like becomes possible later. At this time, if it is difficult to prioritize both storage and display due to the processing speed margin, etc., either of them can be preferentially operated as necessary. Further, regarding the display, it is not always necessary to sequentially display all the data, and the sampling may be performed in time.

When the motor to be measured is mounted and a systematic external force is applied to the mechanism during operation, the motor drive is performed in order to provide a relationship between the timing at which the external force is applied and the timing at which the pulse is applied to the motor under test. A service clock obtained by multiplying the pulse by n is supplied to the outside. For example, in order to set the initial position of the mechanism to be measured prior to measurement when the device to be measured reciprocates, first, apply a pulse of an arbitrary number of steps to an arbitrary rotation direction of the motor to be measured. Means are provided.

In a device in which a plurality of stepping motors operate in synchronization, a plurality of devices of the present invention are used, one of them serves as a master machine, and the other operates as a slave machine, which is effective. Enables measurement.

If calibration is performed in the required frequency range in advance, measurement is possible even when the measurement frequency changes, such as when the motor under test is slowed up or slowed down.

[0021]

Embodiments of the present invention will now be described in detail with reference to the drawings. In the following embodiments, an example will be described in which a mechanical unit driven by a stepping motor measures a change in load torque required for the motor. FIG. 1 is a basic overall configuration diagram showing an embodiment of a measuring apparatus according to the present invention. Each winding (bifilar coil) ΦA, ΦA-, Φ of the stepping motor 1 (four-phase unipolar motor in this example)
One ends of B and ΦB- are connected to the external power source VM applied via the connector 5, and the other ends thereof are connected via the connector 6 to the switching transistors Q1, Q3, Q corresponding to the respective windings.
2, Q4 are connected. By operating the switching transistors Q1 to Q4 at a predetermined timing, the pulse supply to each winding is controlled and the excitation is switched. The switching transistors Q1 to Q4 form a drive circuit 7 that drives a stepping motor.

The controller 9 includes an oscillation circuit that generates a clock that serves as a reference for the pulse supply timing to the windings, a positioning circuit that determines the rotation angle (position) of the stepping motor, and the like. Clockwise rotation clock CCW, excitation mode signal, etc. are generated. The distribution circuit 8 receives the clock CLK and the excitation mode signal, and supplies a pulse for 2-2 phase excitation to each winding.

First, the reference load torque generator 3 is connected via the coupling 4 to the output shaft of the stepping motor 1 as a master motor, which is a non-defective motor whose motor specifications are fixed, and the torque is changed. At this time, the motor drive voltage, the motor drive frequency, the excitation mode, the coil excitation switching transistor, and the accompanying coil counter electromotive force absorption circuit (not shown) are specified. The coil current also changes in response to the torque change, but in order to measure the coil current, the current detection unit 10 inserted in any of the windings (in this example, is inserted in the winding ΦB-). ) Is provided to detect the coil current iB-. This coil current iB-
Is 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 the feature of the torque vs. 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 inventor. See, for example, Japanese Patent Application No. 3-272018 and Japanese Patent Application No. 3-290856.

FIG. 2 shows a current waveform flowing into an arbitrary phase of the HB type stepping motor when the HB type stepping motor is driven at a constant voltage by 2-2 phase excitation. At the time t0 when the current starts to flow into the phase (self-phase current input point) t0, the current shows a negative value. The current increases in the positive direction with the lapse of time, and eventually shows a positive value. After that, 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 portion increases with the increase of the load torque. After time t1 when the current starts flowing into another phase other than the phase of interest (other-phase current input point) t1, the tendency of current increase becomes complicated, and the current does not always increase with an increase in torque.

From the above, when the current value is integrated for the section between the currents t0 and t1 in FIG. 2 where the current has a positive value, the integrated value Q is obtained as shown in FIG. It can be seen that there is a smooth relationship with the load torque TQ. However, the above relationship can be reproduced for motors having the same specifications, but cannot be compared between motors having different specifications. Therefore, in the case of mass production using a large number of motors with the same specifications, once calibrating the relationship between Q and TQ for a typical motor, the motor will flow into the actual motor after that. The load torque TQ can be measured by obtaining the Q from the current flowing. For the PM type motor, Q and TQ are the same as above.
Can ask for the relationship.

FIG. 4 shows current waveforms when the drive voltage is sequentially changed to 13, 12, and 11 V for the same motor as described above. From this, it is found that the characteristics of the current waveform become more prominent when the drive voltage of the motor is lowered. However, if the voltage is lowered too much, the motor will step out and stop. Therefore, it is understood that the motor may be driven with a voltage that is necessary and sufficient to generate the required load torque.
In reality, it is ideal to find the voltage that causes the motor to run out of step when the required maximum load torque is applied, and drive with the optimum drive voltage (E0) that gives a suitable margin to this. It has been found that the relationship between the current waveform feature Q and the load torque TQ, as well as the optimum drive voltage E0, changes depending on the drive frequency of the motor and the operating temperature. Therefore, the calibration should be done over the required range of frequencies and temperatures.

By collecting the necessary data by the above-mentioned calibration and making it into a file, thereafter, with respect to the motor of the same specification mounted on the actual machine mechanism part, even if it is a separate body from the motor used for the calibration, The load torque required by the mechanical unit can be measured by using it as a sensor within the manufacturing error of the motor.

The reference torque generator shown in FIG. 5 can be used as a means for applying a predetermined torque to the motor under test. As a torque generator that is a means for giving a known torque, a perm torque manufactured by Koshin Rashin 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 that indicates the mutual positional relationship between the fixed part and the rotatable movable part and setting the scale to a known value. Is. The torque generator 101 is attached to the support member 103 via the torque generator fixing portion 102. The shaft 105 is coupled to the test motor 107 fixed to the support member 106 and to be calibrated.
Coupled by 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 a small stepping motor with a gear 110 attached to a support member 109 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 large to small while the output shaft is not rotated, the torque is uniform with respect to the rotation of the output shaft due to the residual magnetic effect. The problem of so-called cogging disappears. In order to avoid this problem, in the present embodiment, when the test motor is calibrated, while the torque setting of the torque generator is changed in the decreasing direction,
Rotate the motor under test at an appropriate frequency. In this way, the motor itself can be used as a load torque sensor to dynamically measure the load torque required by the actual machine mechanism 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 give a known load torque to the test motor.
The scale of the reference torque generator can be converted into the number of pulses P supplied to the torque generator setting motor from when the reference torque generator is at the reference position. Therefore, the value P (TQ) of P required to generate the predetermined torque TQ is obtained (step S1). Assuming that the setting motor has already been given a pulse of Pa at this point, the number of pulses PT required to move the motor to a predetermined position is obtained as the absolute value of (P-Pa) (step S2).

The rotation direction of the setting motor is CW for the time being.
(Step S3), and based on the result of comparing P and Pa (Step S4), if P is smaller than Pa, the rotation direction is reset to CCW again (Step S4).
5) In addition, the required pulse number PT is added with the correction amount PB of the backlash caused by the setting motor and the gear (step S6), and the test motor is rotated at an appropriate frequency in order to prevent the above-mentioned cogging. (Step S7). When the rotation direction of the setting motor is CW, there is no risk of cogging, so it is not necessary to rotate the test motor.

The direction of rotation of the setting motor is CW or CC
After deciding on either W, when you are 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) determine the rotation direction of the setting motor (step S1
0), if the rotation direction is not CCW, the setting motor is stopped and the setting work ends (step S16). When the rotation direction is CCW, as described above, the motor to be tested is stopped (step S11), the rotation direction is CW (step S12), PB is PT (step S12), and PB is PT (step S13). , The setting motor is rotated (step S14). After rotating 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 only the backlash correction amount PB. When the setting motor is rotated in the CW direction, there is no risk of cogging, so the test motor may be stopped. Further, as the reference torque generator, in addition to the hysteresis brake, it is also possible to use a powder brake type torque generator with a torque sensor by Bay Black Co. of the United States, as long as it can generate an accurate torque. .

Next, an embodiment in which the measuring apparatus according to the present invention is realized as a system to which a microcomputer is applied will be described in detail. FIG. 7 shows an embodiment of the above system. Microcomputer (CPU) 2 on the bus BUS
13, the ROM 212 and the RAM 211 are arranged in the same manner as in a normal system. In addition, the LCD / software switch driver 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 and constitutes a man-machine interface. As a result, the measurement conditions are input, instructions from the device side, and measurement results are displayed. Furthermore, the GP-IB interface unit 222 or R
Data can be exchanged with an external computer (personal computer) via the S232C interface 223. In addition, the bus has an F that controls the FDD 221.
The DD control unit 220 is connected and the external interface 219 is connected.

Drive pulse generator 20 arranged on the bus
The drive timing of the motor under test 200 is generated from 6 according to an instruction from the CPU 213. The drive circuit 201 for the unipolar type motor or the drive circuit 202 for the bipolar motor is selectively used as necessary. The drive circuit receives power supply from the variable voltage power supply 205, and can be configured by transistors Q1 to Q4 and the like as in the example shown in FIG. By the drive circuit, the measured motor 20
0 is driven. In the drive circuit, as in the case of FIG.
A current / voltage detecting means 207 such as a resistor 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, and then D
It is sequentially stored in the RAM 211 under the control of the MA control unit 208. The sampling is executed by starting the A / D conversion according to an instruction from the trigger generator arranged on the bus. Further, in order to synchronize the timing of sampling generated by the trigger generator with the timing of the motor drive pulse, the trigger generator receives a synchronization pulse from the pulse generator.

Prior to the measurement, under the control of the CPU 213, the reference torque setting machine control unit 209 is controlled, and the drive circuit 204 drives the reference torque setting machine 203.
In the present embodiment, the drive voltage of the motor to be measured needs to be set appropriately in order to make the characteristics of the current waveform noticeable with respect to changes in the load torque. Therefore, the appropriately set voltage is supplied to the drive circuit from the variable voltage power supply 205 arranged on the bus.

FIG. 8 shows how the load torque fluctuates as the motor rotates. (A) shows an example of improper setting. 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 (B). By the way, in the load torque measuring device for the stepping motor of the present invention,
It is possible to dynamically measure the load torque of the actual machine in which the motor is mounted. Therefore, if the measurement result is saved in a file, it can be analyzed by a computer later. According to this purpose, when the measurement data is filed, it is desirable to sequentially file all the data obtained at each measurement point.

When measuring the dynamic characteristics of the torque of the mechanism section using the stepping motor of the type operating at a high frequency, it is necessary to simultaneously display the screen while creating the measurement file, because of the processing speed relationship. It may not always be easy. In such a case, by changing the priority of the file creation work and the display operation as necessary, it becomes possible to supply a measuring device that is easier to use.

When changing the screen settings shown in FIG. 8, eg, using an oscilloscope, the screen settings are initially made to ensure that the display is properly set to perform the measurement. After the actual measurement, it is normal not to change the settings on the screen. However, pay attention to the displayed data during measurement. The CPU requires a considerable amount of processing time to change the screen settings. Therefore, there is no room to reliably store the measurement data in the external storage device while the screen settings are being changed.

Similarly, changing the setting of the screen shown in FIG. 8 has a strong meaning of adjusting the screen prior to the measurement. Therefore, at this time, it is important to display the measurement data according to the setting of the screen, but it is not always necessary to store the measurement data in the external storage device. On the contrary, it is important to surely store the measured data in the external storage device after the setting of the screen is finished and the measurement is started. At this time, it is usually almost unnecessary to change the screen settings.

In consideration of the above, the measurement device according to the present embodiment does not store the measurement data in the external storage device while the screen is set, and conversely stores the measurement data in the external storage device. The screen is configured not to be set when the screen is on.

FIG. 9 shows a flow chart for setting a screen for displaying the measurement result, storing the measurement result in an external storage device, and controlling the storage of the measurement result in the storage device prior to the screen display. There is. The screen and measurement conditions are initialized (steps S21 and S22), and further initialized for writing to the external storage device (step S2).
3) When the initialization is completed, wait until the start button is pressed (step S24). Waiting for the start button to be pressed, the test motor starts rotating (step S2).
5). After that, each time the torque is measured from the test motor (step S26), the save mode (mode in which the measurement data is stored in the external storage device) is determined (step S2).
7) If the save mode is not set, the save is not executed and the screen is set if necessary. At this time, it is judged whether the setting condition is changed (step S33), and if there is no change,
As is, or if there is a 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). Then, when the stop button is pressed, the motor under test is stopped and the measurement is completed (step S3).
2).

As described above, even if the data rate is high, it is necessary to store all of the measured data when storing the measurement data in the external storage device. On the contrary, when all the measurement data are displayed on the screen, it is difficult to visually observe all the data when the drawing speed is high. Therefore, in this embodiment, when the data speed is particularly high and it is difficult to both store the measurement data and draw it on the screen, the operation of storing the measurement data in the external storage device is given priority. The drawing on the display device is of a sampling type, so to speak, it is possible to perform drawing by thinning out intermediate data.

FIG. 10 shows how a systematic disturbance occurs during rotation of the motor to be measured, and the load torque required for the motor under test fluctuates accordingly. In the embodiment shown in FIG. 10, the timing of giving the disturbance is displayed in the phase relationship with the drive pulse of the motor under measurement.

As a specific example, consider the relationship between the paper feed in a facsimile and the timing of printing 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 (b). As a result, the recording paper changes its position with time as shown in (c). Here, as shown in (d), when 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 when the print head and the recording paper stick because the printing is performed. Requires a large torque.

Therefore, as shown in (d '), the printing timing is slightly delayed with respect to the motor driving timing. Then, this time, since the recording paper starts moving and printing is performed, the torque required for both is dispersed over time,
It can be seen that the torque required for the motor decreases as shown in (e ').

In order to control the printing timing described above, in the measuring apparatus according to the present embodiment, as shown in (a), the driving pulse of the motor under test (b) is multiplied by n to be used as a service clock. Supply to the outside. The external device uses the above-mentioned motor drive pulse as a reference and utilizes the above n-multiplied pulse to control the timing of printing for the drive pulse in detail.

FIG. 11 shows an embodiment for generating the n-multiplied pulse. From the source oscillator 201, a frequency clock 1 / n times the frequency required to drive the motor is generated. This clock is supplied as an n-multiplied clock to an external device. The frequency is divided into 1 / n by the frequency divider 202, and then the motor drive pulse generator 203 is subjected to FIG.
It is supplied as a clock as shown in (b).

As a measurement target of the load torque measuring apparatus of the present embodiment, in addition to the case where the motor to be measured is continuously rotated in a fixed direction, the motor to be measured is rotated a fixed number of pulses and then is rotated in the reverse direction. There are various cases. Therefore, in some cases, it may be necessary to move the device under test to the origin before starting the measurement. In such a case, in the device of this embodiment, the test device can be initially positioned by rotating the test motor according to a manual operation instruction.

FIG. 12 shows a flow chart for moving the measured mechanism portion to a predetermined position (initial positioning) prior to the start of measurement. First, the drive frequency of the test motor is initialized to the positioning frequency f0 (step S4).
1). Next, the drive voltage is initialized to the value at the frequency f0 (step S42). CW the measured mechanism until the start button is pressed and the measurement is started.
The press of each button to rotate in the direction CCW or CCW (steps S43 and S4).
5). If the button for instructing rotation in the CW direction is pressed, the motor under measurement is rotated in the CW direction (step S44). If the button instructing to rotate the motor under test in CCW direction is pressed, the motor is
It is rotated in the W direction (step S46). By repeating the above operation as many times as necessary, the initial positioning of the mechanism to be measured is completed.

When the initial positioning is completed and 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 measured motor is set to the measurement frequency fM (step S4
8) Apply the optimum 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.

By the way, when a plurality of the same or different stepping motors are used in the same device, a plurality of load torque measuring devices of the present invention are used in association with each other to simultaneously measure the load torques applied to the plurality of motors. May need to be done. A master / slave function is added to the load torque measuring device of this embodiment to enable efficient measurement. The measuring device designated as the master machine performs the measurement operation as usual, but the GO signal is turned on during the measurement. The measuring device designated for the slave operation executes the measurement while the GO signal from the master unit shows the value of "true". By doing so, it is possible to simultaneously observe the behavior of the load torque characteristics of the plurality of motors that are related to each other by using the plurality of load torque measuring 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 measurement is performed on a device under test that uses a plurality of stepping motors in conjunction with each other. The left side of the figure shows the operation of the master machine, and the right side shows the operation of the slave machine interlocked with the master machine according to instructions from the master machine. First, both the master device and the slave device are initialized (steps S61 and S71) necessary to start the measurement. In the master machine, the value of the signal GO for instructing the slave machine to start / continue the operation from the master machine is cleared (step S62), so the slave machine waits for the GO signal from the master machine,
It is stopped (step S72).

When the start button of the master machine is pressed (step S63), the GO signal is set to true (step S64), and the motor under test connected to the master machine is started to rotate (step S65). The slave machine starts the operation in response to the GO signal of the master machine becoming true (step S72), and starts to rotate the measured motor connected to the slave machine (step S73). After that, in the master machine, the load torque is measured and displayed continuously 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 machine, like the master machine, rotates the motor,
Load torque measurement and display continue (steps S74 and S7
5).

When it is determined that the stop button is pressed in the master machine (step S68), the GO signal is set to false (step S69), the motor to be measured is stopped (step S70), and the measurement is completed. To do. Detecting that the GO signal of the master machine has become false (step S7
6), the slave machine also stops the motor (step S7).
7) The measurement is completed. In this way, the master machine and the slave machines work together, and it becomes possible to measure the operations of the devices having a plurality of motors in synchronization. In the above description, an example in which only one slave machine is shown has been shown, but it is clear that even if there are a plurality of slave machines, 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 the frequency is gradually increased toward the target frequency. Such a method is called slow start or slow up. Conversely, when decelerating or stopping the motor rotating at high speed, the operation reverse to the above may be performed. This is called slowdown. It is necessary to measure the load torque required for the motor to be measured even while the motor to be measured is performing 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 drive voltage of the motor and the drive frequency. Therefore, when performing calibration, the optimum driving voltage is obtained within the required range of the driving frequency, and when the motor is driven at the optimum driving voltage, TQ is set with the frequency as a parameter.
And the relationship between Q and.

In order to measure the magnitude of the load torque applied to the motor during slow-up or slow-down with the motor thus prepared, the instantaneous frequency is detected and the motor under test is optimally matched to the frequency. A driving voltage is applied instantaneously and Q is measured. Then, the torque is measured from the relationship between TQ and Q with the frequency as a parameter.

FIG. 14 shows a flow chart for measuring the load torque of the measured motor including the slow-up stroke. In this example, the description of the slowdown stroke is omitted for simplicity, but is the same as the slowup stroke. First, after the display condition and the measurement condition have been 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 measured motor is set to the self-starting frequency f.
It is initialized to 1 (step S84). Then, the slow-up sequence is started.

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

The relationship between the load torque TQ and the current waveform characteristic Q depends on the temperature of the motor in addition to the above-mentioned parameters. FIG. 15 shows that the motor temperature is 25 for the PM type motor.
It is an example showing the difference in the characteristics of the motor in the case of ° C and 48 ° C. From this, 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 stepping motor can easily raise the temperature by continuously supplying a relatively large current to the coil. However, it is the coil of the motor that is directly heated by this operation. Further, 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 raised to a value to be calibrated by continuing to flow the current through the coil of the motor. When the coil reaches a certain temperature, the temperature of 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 depending on the temperature. Therefore, it is necessary to set the temperature of the entire motor including the magnet to a predetermined value before starting the calibration. Actually, it is not easy to measure and manage the temperature of each part of the motor other than the coil. Therefore, as a generally performed realistic process, when evaluating the characteristics of the motor, a method of starting the measurement after a lapse of a predetermined time after the temperature of the motor becomes constant is applied mutatis mutandis.

FIG. 16 shows a temperature rising process until the calibration is started at a specific temperature. When the motor coil is energized, the coil temperature starts to rise and reaches a predetermined temperature T after tr hours. After that, the coil current is controlled so as to maintain the temperature T. After that, the state maintained at the temperature T is maintained for a predetermined time th. As a result, even if the motor is kept at a predetermined temperature, it can be regarded as a state in which there is no practical use. When the time th has passed, the calibration at the corresponding temperature is started.

FIG. 17 is a flow chart showing the process of raising the temperature of the motor to a predetermined temperature and then performing the calibration after holding the reached temperature for a predetermined time when the motor is calibrated at an arbitrary temperature. First, after setting the calibration conditions (step S101), the temperature of the motor that is not energized is measured by a thermistor or other means, and the resistance value of the motor coil at that temperature is measured to determine the coil temperature and the coil resistance. (Step S102).

When the preparation is completed, the heating 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,
It is measured from the relationship between coil temperatures (steps S104 and S105). In step S106, the coil is continuously energized until it is determined that the coil temperature TP has reached the predetermined temperature TP0. When the coil temperature reaches the predetermined value TPO, the timer t for measuring the holding time is cleared (step S1).
07). After that, the coil resistance is measured (step S10).
8) Obtain the coil temperature TP from this (step S10)
9), TP and TP0 so that TP maintains the predetermined temperature TP0
Depending on the magnitude relationship of the current, the current flowing through the coil is turned on or off (steps S110, S111 and S11).
2). When the state in which the coil temperature is held at the predetermined value TPO continues for the predetermined holding time th, the 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 provide an actual machine mechanism section using the motor itself as a load torque sensor 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 drawings]

FIG. 1 is a basic overall configuration diagram showing an embodiment of a measuring apparatus 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 HB type stepping motor is driven at a constant voltage by 2-2 phase excitation.

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

FIG. 4 is a diagram showing a current waveform when the driving voltage is sequentially changed to 13, 12, and 11V.

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

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

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

FIG. 8 is a diagram showing another embodiment of the present invention, showing how the load torque changes with the rotation of the motor.

FIG. 9 is a screen setting for displaying the measurement result in the embodiment of the present invention, storing the measurement result in an external storage device,
6 is a flowchart for performing control to give priority to storing measurement results in a storage device over screen display.

FIG. 10 is a diagram showing a manner in which a systematic disturbance occurs during rotation of the motor to be measured according to the embodiment of the present invention, and the load torque required for the test motor varies accordingly.

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

FIG. 12 is a flowchart for moving the measured mechanism section to a predetermined position (initial positioning) 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 under test that uses a plurality of stepping motors in conjunction with each other.

FIG. 14 is a diagram showing a flowchart for measuring the load torque of the measured motor including the slow-up stroke in the example of the present invention.

FIG. 15: PM type motor has a motor temperature of 25 ° C.
It is a figure which shows the difference of the characteristic of a motor in case of and and 48 degreeC.

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

FIG. 17 is a flowchart for performing a process of raising the temperature of the motor to a predetermined temperature and then holding the temperature at the reached temperature for a predetermined time and then performing the calibration when the motor is calibrated at an arbitrary temperature.

[Explanation 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
Switch 13, 15 Feature extraction unit 14
Reference value memory 16 Measured value memory 17
Collation judgment unit 18 Display 19
Printer

Claims (9)

[Claims] 1. A characteristic value of a current flowing through a stepping motor, which is obtained when a torque determined by a torque generator is applied to the stepping motor under test, is obtained, and based on relational data between the given torque and the characteristic value. Load torque measuring device for a stepping motor for measuring a load torque acting on the stepping motor, comprising: adjusting means for adjusting a torque generated from the torque generating device. . 2. A characteristic value of a current flowing through the stepping motor, which is obtained when a torque determined by a torque generator is applied to the stepping motor under test, is obtained, and based on the relational data between the given torque and the characteristic value. In a load torque measuring device for a stepping motor that measures a load torque acting on the stepping motor, the torque generated by the torque generating device is connected to the torque generator when the setting value is changed from a current value to a smaller value. A load torque measuring device for a stepping motor, characterized in that it comprises means for rotating the measured motor. 3. A characteristic value of a current flowing through the stepping motor obtained when a torque determined by a torque generator is applied to the stepping motor under test is obtained, and based on the relational data between the given torque and the characteristic value. In a load torque measuring device for a stepping motor 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, and a display mode setting of the display unit are changed. In this case, the load torque measuring device for a stepping motor, comprising: a control unit that controls the storage unit so that the storage is not performed. 4. A characteristic value of a current flowing through the stepping motor obtained when a torque generated by a torque generator is applied to the stepping motor under test is obtained, and based on the relational data between the given torque and the characteristic value. In a load torque measuring device for a stepping motor that measures a load torque that acts on the stepping motor, a display unit that displays the measurement result, a storage unit that stores the measurement result, and in the measurement, prior to the display. A load torque measuring device for a stepping motor, comprising: a control unit that controls so as to store all measured values. 5. A characteristic value of a current flowing through the stepping motor, which is obtained when a torque determined by a torque generator is applied to the stepping motor under test, is obtained, and based on the relational 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 by means of a stepping motor, comprising means for externally supplying a clock having a frequency n times as high as a pulse for driving the stepping motor. Load torque measuring device. 6. A characteristic value of a current flowing through the stepping motor obtained when a torque determined by a torque generator is applied to the stepping motor under test is obtained, and based on the relational data between the given torque and the characteristic value. In a load torque measuring device for a stepping motor for measuring a load torque acting on the stepping motor by means of a stepping motor, the load for a stepping motor is provided with means 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 flowing through the stepping motor, which is connected to each of the plurality of stepping motors to be tested and which is obtained when a torque determined by a torque generator is applied to the stepping motor to be tested, and the given value is given. In a load torque measuring device for a stepping motor, which has a plurality of measuring devices for measuring a load torque acting on the stepping motor based on relational data of the obtained torque and a characteristic value, one of the plurality of measuring devices is a master machine. , A slave device, and means for outputting a signal indicating that the master device is operating, and means for automatically controlling the operation of the slave device in response to the signal. Load torque measuring device for stepping motors. 8. A characteristic value of a current flowing through the stepping motor, which is obtained when a torque determined by a torque generator is applied to the stepping motor under test, is obtained, and based on the relational data between the given torque and the characteristic value. In a load torque measuring device for a stepping motor that measures the load torque acting on the stepping motor by means of a means for storing the characteristics of the current waveform flowing in when a specified load torque is applied, for different frequencies, and for measuring the load torque. A load torque measuring device for a stepping motor, comprising: a means for changing a frequency for driving 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, which is obtained when a torque determined by a torque generator is applied to the stepping motor under test, is obtained, and based on the relational data between the given torque and the characteristic value. A load torque measuring device for a stepping motor for measuring load torque acting on the stepping motor, means for energizing the stepping motor to raise the temperature of the stepping motor, and means for measuring a coil temperature of the stepping motor, A load torque measuring device for a stepping motor, comprising: a means for maintaining the coil temperature of the stepping motor for a predetermined time after the coil temperature reaches the predetermined temperature.