JPH0222561A - Deviation measuring instrument - Google Patents

Abstract

PURPOSE:To measure the deviation of the motion speed of a body in motion and an irregularity of rotation when the body in motion is a rotating body by providing a measuring means, an integrating means, a sample holding means, a measured period arithmetic means, and a deviation arithmetic means. CONSTITUTION:This instrument is provided with the measuring means 3 which measures a set time T1 (T0>T1) from the point of time of an input pulse when a reference period for measuring the period deviation of the input pulse is denoted as T0 and the integrating means 9 which starts integration varying linearly in level from when the output of the means 3 is received and the time T1 is measured. Further, this instrument is provided with the means 10 which samples and holds the output of the means 9 with the input pulse and the mea sured period arithmetic means 12 which finds the interval of sample holding points of time as the period Tx of the input pulse. In another way, the period Tx is not found, the integration output level when the pulse interval of the input pulse is the reference period T0 is regarded as a 0 point, and the period deviation of the input pulse is detected according to the deviation of the output of the means 10 from the 0 point.

Description

Detailed Description of the Invention [Industrial Application Fields] This invention is applicable to, for example, the measurement of deviations in the speed of motion of a moving body, the measurement of uneven rotation when the moving body is a rotating body, and furthermore, the measurement of rotational irregularities when the moving body is a rotating body. This is a deviation measuring device suitable for use in measuring mechanical pitch errors, etc. of a pulse encoder itself that generates pulses with a frequency corresponding to speed.

[Prior Art] When trying to measure uneven motion of a moving body, such as uneven rotation of a rotating body, pulses from a pulse encoder that generates pulses with a frequency corresponding to the rotational speed of the rotating body are usually used for measurement. used for.

Conventionally, in boat fishing, as a method of measuring this movement speed deviation and rotational unevenness, a method of determining it from the frequency of the output pulse of a pulse encoder has been used.

For example, when measuring rotational unevenness, the input pulse, that is, the output pulse of the pulse encoder, is FM modulated due to rotational unevenness (so-called wow and flutter). If input to , this frequency-voltage converter generates a superimposed DC voltage proportional to the frequency of the input pulse and an AC voltage that rises and falls around that DC voltage in proportion to the magnitude of wow and flutter. I get a signal. Therefore, this frequency −
A low-pass filter that passes only the drift component of the output of the voltage converter in the 9 DC to 0.5 Hz band, for example, and a 0.5 Hz band.
By supplying the signal to a bypass filter that passes only wow and flutter components of 2 Hz or higher, the amount of drift and amount of wow and black that the rotating body has can be determined.

[Problems to be Solved by the Invention] However, this method of determining motion unevenness and rotational unevenness from frequency measures the input frequency from information on many input pulses, and therefore, unlike the method of measuring the period, It becomes impossible to respond for each wavelength. In addition, since the input pulse is immediately converted to voltage, the subsequent processing is done in analog mode, and the influence of drift is large.If the sensitivity is increased to detect slight deviations, the drift and deviation of analog values and This results in a number of countries being identified, which is not very accurate.For this reason, conventional methods have drawbacks such as the need for a calibration device to calibrate the rotational unevenness detection device using this frequency-voltage converter. there were.

In addition, with the method of calculating deviation from frequency, it is not possible to measure the deviation for each wavelength of the pulse, so it is not possible to measure the deviation in the rotational phase of each pulse position from the reference phase in one rotation. It is not possible to measure rotational angular velocity unevenness at each rotational angular position (the position of the output pulse of the pulse encoder) based on the reference phase angular position of the rotating body.

Furthermore, if the pulse encoder itself has pitch irregularities, it is not possible to accurately measure the rotational angular velocity irregularities, but for the same reason, it is also impossible to measure the pitch irregularities of this pulse encoder.

Therefore, the pulse interval of the pulses from the pulse encoder,
In other words, one possible method is to measure the pulse period and obtain the error of the measured period from the correct period.

That is, for example, prepare a clock and a counter with a frequency sufficiently higher than the output pulses of the pulse encoder,
This number of clocks included in one period of the pulse from the pulse encoder is counted by a counter, and this count value is calculated as the number of clocks for the set ideal value (the reference period for measuring the period deviation of the input pulse). The periodic deviation can be detected as the difference between the two.

However, when trying to measure the input period to be measured by counting clocks using a single counter, the measurement sensitivity is determined by the clock frequency, and detailed measurements within one clock wavelength cannot be made. First of all, stability is required for measurement. The crystal oscillator normally used as a clock generator is said to have the highest stability around IMHz for boat fishing, and when this frequency is used, the clock resolution is 1μs at IMHz, so this 1μs is the limit of measurement sensitivity.

In addition, as an example of a pulse encoder, a pulse train that is a multiplied pulse by shifting the phase of a pulse generated with mechanical precision, or a pulse train that is a multiplied pulse, or a pulse encoder that electrically converts multiple pulses after a pulse generated with mechanical precision. There is a method that improves the apparent accuracy of a pulse encoder by generating a pulse train that is a multiplication of the output pulses of one pulse encoder.

Since the pulse intervals of the pulses from such a pulse encoder are not spatially constant, it is meaningless to electrically measure the periodic deviation between the pulses. In short, the pulse spacing must be measured with real, mechanical precision and with high spatial precision.

The invention of this application is a deviation measuring device that solves the above problems.

[Means for Solving the Problems] The period deviation measuring device according to the present invention has a reference period T for measuring the period deviation of input pulses.

When the door is closed, there is a measuring means for measuring a set time T, (To > T+) from the time of the input pulse, and the output of this measuring means is received, and from the time when time T1 is measured, the level is sequentially changed to a straight line. an integrating means for starting an integration that varies according to the time; a sample-holding means for sampling and holding the output of the integrating means according to the input pulse; and a period to be measured in which the interval between the sample-holding points is determined as the period Tx of the input pulse. Calculating means and this measured input period T
x and the reference period T. and a deviation calculation means for calculating a periodic deviation from.

Without determining the input period Tx to be measured, the integral output level when the pulse interval of the input pulse is the reference period To is set as 0 point, and the input pulse is calculated based on the deviation of the output of the sample and hold means from this 0 point. This is particularly effective when the T1 measuring means uses a counter that counts clock pulses that are synchronized with the input pulse.

In addition, when the measuring means for T uses a counter that counts clock pulses of a constant frequency that are asynchronous with the input pulse, the phase difference between the sample hold point by the input pulse and the tarok pulse is determined from the output of the sample hold means. A means for determining the period is provided, and the period to be measured calculation means is configured by means for determining the period of the input pulse based on this phase difference and the output of the sample and hold means.

In addition, like a pulse encoder that increases the apparent precision by multiplying the output pulses, it is also possible to use a pulse generating means in which every N (N is an integer of 2 or more) pulses is determined by the original mechanical precision. When used as an input means, a frequency dividing circuit with a frequency division ratio of 1/H is provided for the output pulses of the pulse encoder in order to measure the pulse interval every N determined by its original mechanical precision.

In addition, while switching the value T1 measured by the measuring means,
It is also possible to provide a sensitivity switching means for switching the level gradient in the integrating means while fixing the level at the zero point.

In addition, the input pulse is a means for generating a pulse with a frequency corresponding to the motion speed of a moving body that moves periodically, such as a pulse from a pulse encoder, and the pulse encoder has a pitch error in a spatial pulse array. Sometimes,
A pitch error memory is provided, information on the pitch error of the spatial pulse array of the pulse encoder is written in the pitch error memory, and reference pulse generating means is provided for generating a pulse indicating a reference phase of the periodic motion, The input pulses are counted from the time of the reference pulse from this reference pulse generation means, each input pulse is made to correspond to a memory address, and the input pulse position is calculated from the pitch error memory! A means is provided for reading out pitch error information corresponding to the pitch error information and canceling out this pitch error information.

[Operation] In the present invention, after the measuring means measures a time T1 shorter than the reference period To from the time of arrival of the input pulse, the integrating operation of the integrating means is started, and the integral output is related to the input pulse. This is a sample and hold configuration.

The measuring means only needs to stably measure the set time T, and stability can be ensured by comprising a counter that counts, for example, IMHz stable lock pulses from a crystal oscillator.

Further, since the resolution required within one wavelength of the clock pulse is determined by measuring the period by sampling and holding the integral output, the measurement sensitivity is determined by the accuracy of the integrating means. Therefore, if this integration processing is performed by analog processing, it will have infinite resolution.

In this case, even if the analog processing is not very stable, it is within one wavelength of the clock pulse of the measuring means, so it has little effect on accuracy.

Furthermore, even if the integrating means is configured with a counter that counts clock pulses with a higher frequency than the clock pulses of the measuring means, even if the stability of the tarokk pulse decreases, it is within one clock wavelength, and the accuracy of this high frequency clock will have less impact. It can be considered in the same way as the analog processing described above.

Therefore, by measuring the interval between sample and hold points, it is possible to obtain a highly accurate measured input pulse period.
The deviation measurement accuracy becomes very high.

When the input pulse and the clock pulse of the measuring means are synchronized, the sample hold time and the start time of measurement by the measuring means coincide. Therefore, the sample-and-hold output at the time of the next input pulse corresponds exactly to the sample-and-hold time interval. In this case, the sampled and held integral value becomes a vaguely determined value when the pulse has a reference period, and the period deviation is obtained as a deviation from this value. However, compared to simply counting clock pulses to measure the period, the sample-and-hold output of the integral output is performed using an analog method with no 1-count error, so the accuracy is improved, so the input pulse and clock pulse are synchronized. There is no need to do so.

When the input pulse and the tarokk pulse in the measuring means are asynchronous, find the phase difference that occurs between the sample and hold time and the clock pulse, and add this to the calculation of the input pulse period to be measured or set it to $4. By using this, the accuracy can be further improved.

The sensitivity switching means changes the time T measured by the measuring means, and also changes the level slope in the integrating circuit so that the level at the zero point does not change. That is,
Even if the reference period To is the same, by changing the time T, the time interval at which the integration is performed changes, the level slope of the integration is changed accordingly, and the measurement sensitivity changes.

A means for obtaining pulses with a frequency corresponding to the motion of a moving body, such as a pulse encoder, is not ideal, but an output pulse with improved apparent pulse accuracy obtained by multiplying the original mechanical precision pulse by N. For the pulses from the pulse generating means that generate
Since the pulses have a tt precision, the period deviation of each N pulses is measured using an L/H frequency dividing circuit.

Furthermore, if there is a pitch error in the spatial pulse array, the pitch error at the position of each input pulse is read out from the pitch error memory, and the set value T1 is corrected accordingly. When this value T is changed, the reference period T.

is changed to a value including the pitch error, and as a result, the influence of the pitch error of each pulse encoder can be removed from the measured period Tx.

[Embodiment] FIG. 1 shows an embodiment of the deviation measuring device according to the present invention. This example is a case where the moving body is a rotating body.

In the figure, reference numeral 1 denotes a pulse encoder that is attached coaxially to a rotating body, for example a motor, and generates pulses PI of a frequency corresponding to the rotational speed of the rotating body.

A clock generator 4 generates a clock pulse CK whose frequency is sufficiently higher than that of the pulse PI. In this example, this clock pulse CK is set to IMHz. Clock pulse C from this clock generator 4
K (FIG. 2B) is supplied to the clock terminal of the down counter 3.

Reference numeral 5 denotes a preset value setting means in which, when the measurement cycle is an ideal value, that is, the reference cycle To, a count value corresponding to the number of tallock pulses CK included in the cycle To is set therein. In other words, the reference period is set to this. This preset count value is supplied to the counter 3 via a preset value correction means 6, which will be described later.

Then, the pulse PI (FIG. 2A) from the pulse encoder 1 is supplied to the load terminal of the down counter 3 via the buffer amplifier 2 for waveform shaping.

Therefore, in the down counter 3, the reset count value is reset by the input pulse PI, and the clock pulse CK is sequentially counted down from this preset count value (see FIG. 2C).

The count value of this counter 3 is supplied to a comparator 7. On the other hand, the comparator 7 is supplied with a constant K from a constant setting memory 8.

This constant is changed according to sensitivity switching as described later. In the example of FIG. 2, K=1.

The comparator 7 compares the constant from the constant setting memory 8 with the count value of the counter 3, and when the two match, a match output SE (FIG. 2D) is obtained.

This coincidence output SE is supplied to the integrating means 9.

The integrating means 9 starts an integrating operation to linearly change, for example increase, the level from the point of output SE. In this case, the integrating means 9 may be configured as an analog circuit using a constant current circuit and a charging/discharging circuit, or may be configured as a digital circuit by counting tallock pulses having a higher frequency than the clock pulse CK with a counter. It may also be configured as a circuit.

The output SI of this integrating means (FIG. 2E) is supplied to sample and hold means 10.

The input pulse PI via the buffer amplifier 2 is supplied to the sample and hold means 10 as a sample and hold pulse, and this pulse PI causes the output SI of the integration means 9 to be
is sampled and held.

This sample and hold output is supplied to the A-D converter 11, converted into a digital value, and supplied to the period under measurement calculation means 12.

The period to be measured calculation means 12 is also supplied with a preset value corresponding to the reference period T obtained from the preset value setting means 5 via the preset value correction means 6, and also supplied with a constant from the constant setting circuit 8. K is supplied.

Here, as is clear from FIG. 2, the accurate period to be measured is just between the sample-and-hold time of the current input pulse and the sample-and-hold time of the input pulse one cycle before.

In this case, if the input pulse PI and clock pulse CK are synchronized, for example by using a PLL circuit, as shown in FIG. 3A and B, then the input pulse one cycle before Since the sample hold point coincides with the loading point of counter 3, that is, the counting start point, the period to be measured Tx is determined by the output SE from comparator 7 after counter 3 is loaded, as is clear from the figure.
It is determined as the sum of the time T until the sample and hold output is obtained and the time T2 corresponding to the sample and hold output.

The time T1 is determined from a preset value and a constant.

When this pulse PI and clock pulse CK are synchronized, the period of the input pulse PI is the reference period T.
o, the sample-and-hold output reaches a fixed predetermined level (hereinafter referred to as 0), as shown in FIG. 3E.
Therefore, using the 0 point level at this reference period T as a reference, the level deviation from this 0 point level is converted into a period deviation ΔT (=To Tx) and used as period deviation information. From now on, the period to be measured T
x can be found. Note that the value obtained by dividing this period deviation by T by the reference period To can also be expressed as a percentage and used as a deviation calculation output, which will be described later.

In this way, input pulse PI and tarokku pulse C
When the clock pulse CK is synchronized with the clock pulse CK, the value of the reference period T can be set finer than one period of the clock pulse CK as follows.

That is, a delay circuit is provided between the comparator 7 and the integrating means 9, which can change the delay time back and forth around one cycle of the clock pulse CK. As this delay circuit, a monostable multivibrator whose time constant can be changed by, for example, a variable resistor or a variable capacitance element can be used. Then, as shown in FIG. 3C, the constant K is set to K = 2 in this case, and 1
Before the cycle, a coincidence output SE'' is obtained as shown by the dotted line in the third diagram, and the monostable multivibrator is triggered by this coincidence output SE''.

Then, a delayed signal M as shown in FIG. 3F is obtained from the monostable multivibrator, and the integrating means 9 starts integration from the falling edge of this delayed signal M. Therefore, the output Sl of the integrating means 9 is as shown in FIG.
Depending on the delay time in the delay circuit, the movement occurs in parallel in time. Therefore, as is clear from FIG. 3G, the time for the integral output SI to reach the 0-point level changes,
Reference period T. The value of is changed more finely than one period of the clock pulse CK. Thereby, it is possible to measure the period deviation with respect to the reference period with a finer precision than the period of the clock pulse CK.

By the way, in the example of FIG. 1, the input pulse PI and tarokku pulse CK are asynchronous as shown in FIG. As shown in FIGS. C to E, there is a phase difference ERT between the sample hold time of the input pulse PI and the time of the clock pulse CK, which is the load time of the counter 3.

Therefore, the accurate measured period Tx from the sample hold point to the next sample hold point is (T
1+T2+ERT).

The phase difference ERT can be determined from the sample and hold output as follows.

That is, the integration circuit 9 starts integration in synchronization with the clock pulse CK as described above. Therefore, a certain correspondence exists between the sample and hold output and the pulse position of the clock pulse CK. In other words, if the frequency of the clock pulse CK is known, each level of the integral output indicates a deviation from the clock pulse CK, so the phase difference ERT can be determined from the sample-and-hold output.

Therefore, in this example, the calculation means 13 of this phase difference ERT
is provided, and the digital output of the sample and hold means 10 from the A-D converter 11 is supplied to this calculation means 13, and the phase difference ERT is determined.

The obtained phase difference ERT is supplied to a memory circuit 14 made up of, for example, a D flip-flop circuit, and written by an input pulse PI slightly delayed by a delay means 15. Due to the presence of the delay means 15, at the time of the next input pulse PI, the phase difference BRT at the time of the pulse one cycle before is obtained from this memory 14. Then, this phase difference ERT of one cycle before is supplied to the period to be measured calculation circuit 12.

Therefore, accurate information on the measured period Tx can be obtained from the measured period calculation means 12.

Note that the sample-and-hold output of one cycle before is memorized, and when calculating the period to be measured Tx from the sample-and-hold output of the next input pulse, the phase difference ERT is calculated from the sandal-hold output of this one cycle before. You may also do so.

This information on the period to be measured Tx is supplied to the deviation calculation circuit 16. Further, the deviation calculation circuit 16 is supplied with a preset value from the preset value correction circuit 6. The deviation calculation circuit 16 then calculates the deviation of the measured period Tx from the reference period TO in percentage.

In this example, the deviation is calculated by converting it into a frequency deviation. That is, the reference frequency is f. , the frequency to be measured is fx
When, Deviation = L-5-j-L x 100 (X)Q = (1/Tx 1/To) x'l'
o X 100= (To /Tx 1)X
It becomes 100 (%). If the pulse encoder does not have a pitch error in the spatial pulse array, this deviation is
This example shows the rotational unevenness (rotational angular velocity unevenness) of the motor at the rotational angular position of the pulse PI.

The surface difference obtained in this way is taken out to the output terminal 17,
For example, if it is supplied to a meter that touches the center around 0%,
This meter provides a visual indication of the deviation.

In this way, when the cycle deviation measurement for one pulse is completed, the pulse PI is delayed by the delay circuit 18, and the integration circuit 9 is reset, and the next input pulse P
Preparation is made to measure the period of I.

In this example, the period measurement sensitivity can be switched as follows.

That is, 19 is a sensitivity switching means, and the sensitivity switching signal from this is supplied to the constant setting memory 8 and also to the integrating means 9.

In the constant setting memory 8, the constant K is switched. When the constant K is switched to 3 to K l + K 2 as shown in FIG. 4, the time T1 from when the down counter 3 is loaded until the coincidence output SE is obtained from the comparator 7 becomes 'r ,'r+2°T, changes to 3.

Therefore, in the integrating means 9, the starting point of integration changes. In this integrating circuit 9, even if the starting point of integration changes, the input pulse P as shown in FIG.
The period of I is the reference period T.

The slope of the integral is changed so that the level at the zero point position described above when .

In this case, since the frequency of the tarok pulse CK is IMHz and the taroch pulse interval is 1 μsec, for example,
If K = 1, deviations in the range of ±1 μs can be measured, and K
= 10, deviations within a range of 10 μsec can be measured.

Furthermore, if K=100, deviations within a range of 100 μsec can be measured.

As the deviation measurement range becomes narrower, the level slope in the integrating means 9 becomes steeper, so that the measurement sensitivity becomes higher. In this way, by changing the value of K, the measurement sensitivity can be changed.

The above is a case where the deviation in the rotation of a rotary moving body is measured assuming that there is no pitch error in the spatial pulse array of the pulse encoder 1 itself, but in this example, the influence of this pitch error of the pulse encoder 1 itself is measured. I am making it possible to remove it.

That is, in this example, the pitch error memory 20 is provided,
Information on the pitch error at each generation position (rotational angular position) of the pulse PI from the pulse encoder 1 is written in this memory 20 for one rotation of the pulse encoder 1, with a predetermined rotational angular position as a reference position, and Using this pitch error information, the ideal center value for period measurement, that is, the set value (preset value of the counter) of the reference period T0, is corrected every time one pulse P■ is input. In this way, if the pitch error information is included in the set value, the measured surface difference is canceled out by the pitch error, so that the rotational angular velocity unevenness of the rotating body itself can be accurately measured.

This pitch error information can also be obtained using a separate special measuring device and written into the memory 20. In that case, the memory 2o may be a nonvolatile memory.

However, in this example, RA is used as the pitch error memory 20.
M is used, and pitch error information can be appropriately written into this memory 20 by using the above-mentioned period deviation measurement output.

That is, the pulse encoder 1 is rotated by inertia at a high rotational speed using, for example, a flywheel. In such a rotating state where the rotating body rotates with inertia at a high rotational speed, the rotational unevenness of the rotating body can be ignored, so if there is a periodic deviation, it is considered to be a pitch error of the pulse encoder 1 itself.

Therefore, each pulse PI is counted from the reference position of the rotational phase angle, each pulse PI is made to correspond to an address, and the pitch error at the rotational angle position of the pulse PI is written in the memory 20. As a result, the memory 2o stores the pulses. The pitch error at the rotational angular position of each pulse PI for one rotation of the encoder 1 is stored.

Therefore, this example is configured as follows.

First, the aforementioned deviation information for each pulse PI from the deviation calculation means 16 is supplied to the pitch error memory 20 via the switch circuit 21. A write/read controller 22 is also provided. The write/read controller 22 is provided with a switch (not shown) for controlling writing and reading of pitch errors. The write/read control signals from this controller 22 are supplied to the memory 20, and
The signal is supplied to the switch circuit B21. Then, during writing, the switch circuit 21 is turned on.

On the other hand, a reference pulse generator 23 is provided which generates a reference pulse PG of one rotation period indicating the reference position of the rotational phase angle of the pulse encoder 1. This reference pulse PG is then supplied to the reset terminal of the address counter 24. Further, the pulse PI from the pulse encoder 1 is passed through the buffer amplifier 25 for waveform shaping to the address counter 2.
4.

Therefore, from this address counter 24, for one revolution of the pulse encoder, the address of the rotational angle position of each pulse PI is obtained with the position of the pulse PG as the reference rotational phase angle position. The address signal from the address counter 24 is supplied to the address terminal of the pitch error memory 20.

Then, at a high rotational speed, the deviation (pitch error) from the deviation calculation means 16 at the rotational angular position of each pulse PI from the pulse encoder that is rotated by inertia is written into the memory 20 according to the address from the counter 24. It will be done.

When normally measuring deviations such as uneven rotation of a rotating body,
The controller 22 puts the memory 20 in a read state. Therefore, when measuring this deviation, this memory 2
0, the pitch error of the pulse encoder 1 itself at the rotation angle position of each pulse PI with reference to the reference rotation phase angle position of the pulse encoder 1 is read out, and this is supplied to the preset value correction means 6, and the pitch error is The preset value is corrected accordingly.

As described above, even if there is a pitch error in the pulse encoder, it is possible to measure the rotational angular velocity deviation with high accuracy without being affected by this pitch error.

Note that when pitch error information is not written in the memory 20, a 0% correction signal is always read out from the memory 20, and this is supplied to the preset value correction means 6.

Note that instead of correcting the preset value, the constant K from the constant setting memory 8 may be corrected. Also, if the frequency of the clock pulse CK can be changed, the frequency of the clock pulse CK may be changed to the pitch. It may be changed to offset the influence of the error. The key is the reference period T to be set. What is necessary is to substantially correct the pitch error so that the pitch error can be canceled out.

FIG. 5 shows another example of the period measuring device according to the present invention, in which the same parts as in the example of FIG. 1 are given the same reference numerals.

In this example, the integrating means 9 is constructed digitally using a counter.

That is, the integrating means 9 includes the counter 91 and the PLL circuit 9.
2 and a variable frequency dividing circuit 93.

The clock pulse CK from the tarlock generator 4 is supplied to the PLL circuit 92, and a clock pulse with a frequency obtained by multiplying this clock pulse CK by 100, for example, is used as the clock pulse for this PLL circuit.
It is obtained from the L circuit 92. The clock pulse from this PLL circuit 92 is supplied to the tally terminal of the counter 91 via the variable frequency dividing port F#193. The counter 91 changes the count value at a speed corresponding to the frequency of the clock pulse passed through the variable frequency divider circuit 93. In other words, integration is performed in which the count value changes with a slope depending on the frequency of the clock pulse.

In this example, the level slope of the integration during sensitivity switching by the sensitivity switching means 19 is changed by changing the frequency division ratio of the variable frequency division circuit 93.

This integrated output is supplied to a latch circuit 101 serving as sample and hold means 10.

Furthermore, in this example, as described above, the pulse encoder 1 outputs a pulse with pseudo-improved precision, which is a multiplication of a pulse with spatial mechanical precision. This is sometimes the case when the deviation can be measured with respect to the original precision output pulse before multiplication.

Therefore, in this example, a variable frequency divider circuit 30 is provided on the output side of the amplifier 2.

Then, a pulse obtained by frequency-dividing the input pulse PI by the variable frequency dividing circuit 30 is supplied to the load terminal of the down counter 3, is supplied to the latch circuit 101 as a latch pulse, and is also supplied to the memory circuit 14. Ru. In this case, the memory circuit 14 stores a phase difference ER process corresponding to the tarok pulse accuracy from the variable frequency divider circuit 93.

In this case, it is necessary to change the time from when the counter 3 is loaded until the coincidence output SE is obtained from the comparator 7, depending on the frequency division ratio of the frequency divider circuit. This can be handled by changing the preset value, changing the constant K, or changing the frequency of the clock pulse CK, but in this example, the clock pulse CK from the clock generator 4 is divided by the frequency of the variable frequency divider circuit 30. The clock pulse CK is supplied to a variable frequency divider circuit 31 whose frequency division ratio is changed according to the ratio, and the clock pulse CK is supplied to the clock terminal of the counter 3 with its frequency changed.

Furthermore, since the input pulse is frequency-divided, the measurement sensitivity must be substantially lowered, so the frequency division ratio of the variable frequency divider N93 can be changed in the same way.

These frequency division ratios are changed as follows.

The variable frequency dividing means 30.31 and 93 can be constituted by counters with variable preset values, for example.

32 is a frequency division ratio supply means, and this frequency division ratio supply means 32 is as follows:
For example, it is composed of a ROM, and each frequency division ratio (preset value) is read out by a change signal (address signal) from the frequency division ratio changing means 33. Then, the read frequency division ratio is supplied to the variable frequency division circuits 30 and 31, and is also supplied to the variable frequency division circuit 93 via the sensitivity switching means 19.

According to the above configuration, the frequency deviation of the pulse PI is obtained by dividing the pulse PI according to the frequency division ratio in the frequency dividing circuit 30, and the deviation calculating means 16 converts the period deviation into rotational angular velocity unevenness. can get. Therefore, for example, when the input pulse PI is a pulse from a pulse encoder designed to obtain an output pulse in a doubled state, correct rotation deviation can be achieved by setting the frequency division ratio of the frequency dividing circuit 30 to 1/2. can be measured.

In this case, it is necessary to write the period deviation with respect to the frequency-divided output pulse into the pitch error memory 20 as a pitch error. Therefore, once the frequency division ratio is set, in that state, the pulse encoder is rotated at high speed by inertia as described above, and the output of the deviation calculating means 16 at that time is written in the memory 20.

However, the write/read address in this case needs to be determined according to the frequency-divided output pulse.

Therefore, in this example, address counter 24 and memory 2
A latch circuit 34 is provided between the address counter 2 and
The address signal from 4 is latched by the output pulse of the variable frequency divider circuit 30.

As in the case of the above explanation, when the multiplication ratio of the pulses from the pulse encoder is known, the above-mentioned frequency division ratio can be set manually. 35 is a manual setting means for this purpose, and a setting signal from this is supplied to the frequency division ratio changing means 33 via a switch circuit 36 for manual/auto switching, whereby the frequency division ratio is manually set. Ru.

Incidentally, the multiplication ratio of the pulses from the pulse encoder is not always known. Therefore, in this example, the frequency division ratio is automatically determined in accordance with the multiplication ratio.

That is, 41 is a search signal generating means, and when the switch circuit 36 is switched to the auto side as shown in the figure, the search signal is supplied to the frequency division ratio changing means 33, and thereby the frequency division ratio supplying means 32 outputs each division. A frequency division ratio that sequentially changes every multiple revolutions of the pulse encoder 1, for example every 5 revolutions, is supplied to the circuit 30, 31, 93. At this time, an error of 0% is read out from the pitch error memory 20 for any address. In other words, the pitch error of the pulse encoder 1 is not corrected.

Then, the deviation output of the deviation calculation means 16 at each frequency division ratio is supplied to the memory circuit 40.

Further, the pulse from the variable frequency divider circuit 30 is supplied to the clock terminal of the address counter 42, and the reference pulse PG of one rotation period from the reference pulse generator 23 is supplied to the reset terminal of the address counter 42. The address signal from this address counter 42 is then supplied to the memory circuit 40.

The memory circuit 40 is configured with, for example, three memories that store calculation deviation outputs for one rotation. A reference pulse PG is supplied to this memory 40, and the memory to be written into and the memory to be read from are switched for each reference pulse PG. When writing to two of the three memories is completed, writing to the remaining memories is started, and deviation output information for two rotations from the two memories for which writing has been completed is sent to the stationary detection means. Transferred to 43.

The stationary detection means 43 compares the deviation output information for the two rotations with the same addresses designated by the address counter 42.

Here, the frequency division ratio of the frequency divider 30 is 1. The N value of /N is the number of pulses PI per revolution of the pulse encoder 1.
If the value M is not divisible when divided by the value,
As shown in FIG. 6, since there is an indivisible remainder pulse for each rotation, the output pulse of the frequency dividing circuit 30 is M- During one rotation, M is always at a spatially different position.
This means that the pulse interval of each pulse PI is measured. Then, from the Mth rotation, this is repeated. On the other hand, the rotational unevenness inherent to a rotating body for one rotation is
Since it is considered that it will always remain the same, if the stationary detection means 43 compares the deviation output of two consecutive rotations, the counter 4
The deviations between the same address positions specified by 2 will be different.

On the other hand, when the N value of the frequency division ratio corresponds to the multiplication ratio, the number of pulses PI per revolution of the pulse encoder 1 is always divisible, so in each revolution, every N pulses PI are at the same position. The interval between pulses will be measured. Therefore, the deviation output for multiple rotations stored in the memory 4° indicates that the deviation at the same address position specified by the counter 42 is always equal, or if there is an offset for each rotation, only that offset value. It will be different.

Therefore, when the stationary detection means 43 compares the deviation output information for at least two consecutive rotations from the memory 40 and calculates the difference between the two at the same address position, the N value corresponds to the multiplication ratio. When, the difference between the two is 0,
Alternatively, all the values are offset values. On the other hand, if the N value is a value M that cannot evenly divide the number of pulses for one rotation as described above, the difference between the two will be different at each address position.

Therefore, when the difference is 0 or all the offset values, the stationary detection means 42 obtains a stationary detection output from this,
As a result, the search signal from the search signal generating means 41 is stopped, and each frequency dividing circuit 30, 31.93 is fixed at the current frequency division ratio.

As described above, even if the pulse encoder has an unknown multiplication ratio, it is possible to automatically set a frequency division ratio corresponding to the multiplication ratio.

In addition, if the N value of the frequency division ratio 1/'N of the frequency dividing circuit 3o is a value M that is not evenly divisible when the number of pulses PI per rotation of the pulse encoder 1 is divided by the N value, , as shown in FIG. 6, since there is an indivisible remainder pulse for each rotation, the output pulse of the frequency dividing circuit 30 is expressed as During M-1 rotations there are always pulses PI at spatially different positions. Therefore, the addresses from the latch circuit 34 are different for each M-1 rotation, even if they have the same order as counted from the reference pulse PG. This is then repeated from the Mth rotation.

On the other hand, if the N value is a value that can evenly divide the number of pulses PI per revolution of the pulse encoder 1 by its Ni, the output pulse ° of the frequency dividing circuit 3o is
When viewed in units of one revolution based on the position of the pulse PG,
The pulse PI is always at the same spatial position. Therefore, the address from latch turn 17J34 is 1 turn each time,
Pulses that have the same order when counted from the reference pulse PG are the same.

From the above, by comparing the addresses of the latch circuit 34 for multiple rotations, the variable frequency divider circuit 30
Alternatively, the frequency division ratio may be set.

Note that even if the pulse encoder is of the type that interpolates one or more pulses between two pulses, as long as it can obtain a pulse that indicates the reference phase angle position of one revolution, it will work in exactly the same way as described above. The division ratio can be automatically set by

The above explanation is for measuring the periodic deviation when the moving body is moving at a constant speed. However, when the moving body is accelerating or decelerating, for example, the reference pulse By changing the frequency or period of the PG, it is possible to measure the periodic deviation of an input pulse having a frequency corresponding to the moving speed of the moving object even when the moving object is speeding up or decelerating.

Note that the present invention is applicable not only to pulses from a rotary pulse encoder but also to pulses from other pulse encoders as input pulses.

Further, instead of directly sampling and holding the integral output using the input pulse, it may be possible to sample and hold the integral output using a pulse obtained by supplying the input pulse to a monostable multivibrator.

Further, according to the present invention, since it is possible to measure the period deviation for each pulse, it is possible to measure the period deviation not only of pulses from the pulse encoder but also of various input pulses.

Further, in the above example, a case has been described in which the deviation is measured for a rotating body, but the deviation can be measured even for a rotating body that performs periodic motion such as reciprocating motion. If a signal indicating the reference phase of this periodic motion can be obtained, it is possible to measure the pitch error due to the spatial pulse arrangement of pulses with a frequency that corresponds to the speed of this reciprocating motion. It is possible to remove the influence of pitch error and perform measurement once.

Note that the configuration of each part in the example of FIG. 1 and the example of FIG. 5 is not limited to a hardware configuration, but can also be appropriately processed by software using a computer.

[Effects of the Invention] The present invention operates the integrating means from a predetermined time point before the reference period of the input pulse to be measured has elapsed from the arrival point of the input pulse, and samples and holds the integrated output using the input pulse. However, the configuration is such that the interval between the sample hold point one cycle before and the sample hold point at that time is determined as the period to be measured.

Therefore, as long as the time measuring means for starting the integrating operation of the integrating means can measure time stably, it will not affect the measurement accuracy, and the IMHz clock pulses of a highly stable crystal oscillator can be counted by a counter. It is possible to use one with a configuration that

If the integrating means is constituted by an analog circuit, infinite resolution can be obtained, making it possible to measure deviations with extremely high precision. At this time, even if the stability of the analog processing is not good, since it occurs within one wavelength of the stable IMHz clock of the measuring means, it has little effect on accuracy.

Furthermore, when a counter that counts tally clock pulses that are multiplied by an I MHz clock pulse is used as an integrating means, the accuracy will depend on the frequency. At this time as well, the high frequency clock pulse becomes unstable, but for the same reason as in the case of analog processing, it has little effect on accuracy, and highly accurate deviation measurement is possible.

In addition, since the period to be measured is determined as the interval between sample and hold points, if the measuring means that determines the start point of operation of the integrating means is configured with a counter, it is difficult to synchronize or asynchronously synchronize the input pulse with the tally pulse of the measuring counter. Very accurate deviation measurements can be made regardless of the relationship.

Another feature is that the deviation measurement sensitivity can be changed simply by changing the time at which the integrating means starts operating and the integration slope of the integrating means.

Furthermore, since the period of the input pulse can be precisely measured for each wavelength, the deviation from the reference value can be accurately obtained for each wavelength.

Therefore, when the input pulse corresponds to a periodic motion and the reference phase position of the periodic motion is fixed, the deviation in the position of each input pulse with respect to the reference phase position is calculated from the reference period. Since it can be obtained as a percentage of the deviation, it is also possible to detect this as a deviation at each pulse position during one period and store it in a memory.

In addition, since the periodic deviation is measured for each wavelength, when the input pulse is a pulse from a pulse encoder, a memory is required to store pitch error information at each pulse position relative to the reference phase position. Since the reference period can be corrected using the pitch error information from this memory, even if there is a pinch error in the pulse encoder, it is possible to measure the deviation with this pinch error removed.

In addition, even though the input pulse is a multiplication of the pulses that are spatially arranged with the original tR mechanical precision, in this invention, since a frequency dividing circuit is provided for the input pulse, the original The pulse period can be constantly measured.

Moreover, according to the present invention, even if the warp multiplication ratio of the input pulse is unknown, it can be automatically detected, making it very easy to use.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIGS.
FIG. 4 is a time chart for explaining the same, FIG. 5 is a block diagram of another embodiment of the present invention, and FIG. 6 is a diagram for explaining the same. 1 is a pulse encoder, 3 is a counter constituting a measuring means, 4 is a tarok generator, 9 is an integrating means, 10 is a sample hold means, 12 is a measured period calculation means, 13 is a phase difference calculation means, and 14 is a phase difference 16 is a deviation calculation means, 20 is a pitch error memory, 23 is a reference pulse generation circuit that generates a reference pulse indicating a reference for a rotational phase;
24 is an idle counter. Agent Patent Attorney Masami Sato

Claims (7)

[Claims] (1) A measuring means for measuring a set time T_1 (T_0>T_1) from the time of the input pulse, when the reference period for measuring the period deviation of the input pulse is T_0; an integrating means that receives the output and starts integration whose level sequentially changes linearly from the time when the above-mentioned T_1 is measured; a sample-hold means that samples and holds the output of the integrating means in relation to the above-mentioned input pulse; A deviation measuring device comprising: a period to be measured calculation means for determining the interval between the sample and hold times as the period Tx of the input pulse; and a deviation calculation means to calculate a period deviation from the period to be measured Tx and the reference period T_0. (2) A measuring means for measuring a set time T_1 (T_0>T_1) from the time of the input pulse, when the reference period for measuring the period deviation of the input pulse is T_0; an integrating means that receives the output and starts integration whose level sequentially changes linearly from the time when the above-mentioned T_1 is measured; a sample-hold means that samples and holds the output of the integrating means in relation to the above-mentioned input pulse; The integral output level when the pulse interval of the input pulse is the reference period T_0 is set as 0 point, and the period deviation of the input pulse is detected based on the deviation of the output of the sample and hold means from this 0 point. A deviation measuring device consisting of calculation means. (3) The measuring means T_1 is a counter that counts a clock of a constant frequency that is asynchronous with the input pulse, and the measurement means calculates the sample and hold time related to the input pulse and the clock pulse from the output of the sample and hold means. means for determining the phase difference of the input pulse;
The deviation measuring device according to claim 1, wherein the device is a means for determining x. (4) Claim (1) wherein a frequency dividing circuit is provided for reducing the disturbance in the wavelength of the pulse due to multiplication or the like with respect to the input pulse, and the output of the frequency dividing circuit is supplied to the measuring means.
, (2) or (3). (5) The input pulse is an output pulse of a pulse generator having a frequency corresponding to the speed of a moving body that moves periodically, and the frequency dividing circuit is a variable division ratio frequency dividing circuit. and a reference pulse generating means for generating a reference pulse indicating a reference phase of the periodic motion of the moving body, and a counter that is reset by the reference pulse from the reference pulse generating means and counts the input pulse based on the count value of the counter. hand,
means for determining the address of the generation position of each pulse from the variable frequency divider circuit using the reference phase position of the moving body as a reference address; a memory into which the output of the sample hold means is written in accordance with the address; Compare the readout output signals for each periodic movement of the moving body for at least two consecutive times, and determine whether the same pattern is obtained as a periodic deviation pattern for one periodic movement. a determining means for sequentially changing the frequency division ratio of the variable frequency dividing circuit, and receiving an output from the determining means to determine whether the same pattern is obtained as a periodic deviation pattern for the one periodic movement; 5. The deviation measuring device according to claim 4, further comprising means for fixing the frequency division ratio when the frequency dividing ratio is fixed. (6) Claims (1), (2), (3), (4) or (
5) The deviation measuring device as described above, further comprising sensitivity switching means for switching the T_1 and switching the level slope in the integrating means while fixing the level at the zero point. (7) The input pulse is an output pulse of a pulse generating means having a frequency corresponding to the speed of movement of a moving body that makes periodic motion, and is a standard for generating a reference pulse indicating the reference phase of the periodic motion of the moving body. A pulse generating means is provided and a pitch error memory is provided, and information on the pitch error of the spatial pulse array of the pulse generating means is written in the pitch error memory, and the reference phase from the reference pulse generating means is stored in the pitch error memory. The pitch error information is read from the pitch error memory using the output of the counter that counts the input pulses as an address, and this pitch error information cancels out the pitch error in the input pulse. Claims (1), (2), (3)
, (4), (5) or (6).