JPH11190606A - Rotation quantity measuring method and rotation quantity measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation quantity measuring method and a rotation quantity measuring device that can measure rotation quantity with accuracy without calibrating a rotating speed detecting sensor by a calibrating device. SOLUTION: The physical quantity of magnetic flux or the like is regularly changed in association with the rotation of a rotating shaft of a motor M, and the change of the physical quantity is converted into the signal change of two voltage or the like different in phase. In the case of converted signal waveform having discrepancy from normal waveform, this discrepancy is dissolved by a signal waveform correcting means 21, and a rotation quantity computing means 22 computes the rotation quantity such as rotation frequency and a rotating position on the basis of the corrected signal change.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation amount measuring method and a rotation amount measuring device. More specifically, the present invention relates to a rotation amount measuring method and a rotation amount measuring device with improved measurement accuracy.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
A rotation amount detection sensor c is provided at the rear end of the drive shaft b to measure the rotation amount of the motor a. In order to maintain or improve the measurement accuracy of the rotation amount detection sensor c, as shown in FIG. 7, the calibration of the rotation number detection sensor c by the calibration device e having the reference sensor d calibrated with high accuracy is performed. It is done regularly during or after use. The calibration of the rotation speed detection sensor c by the reference sensor d is performed, for example, by rotating the driving device f to which the reference sensor d is connected, and converting the measurement value of the rotation speed detection sensor c obtained at that time into the measurement value of the reference sensor d. The adjustment is performed by adjusting the gain of the rotation speed detection sensor c and correcting the waveform distortion in the calibration unit g so that they match.

However, the conventional method has a problem that the calibration device e is expensive because the reference sensor d is expensive. Further, at the time of calibration, the rotational speed detection sensor c attached to the motor a or the like must be removed and attached to the calibration device e, which causes a problem that the calibration work becomes complicated. Further, there is a problem that it is not possible to correct the deviation of the gain and the offset which are likely to occur during the actual operation.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is intended to measure the rotation amount with high accuracy without calibrating the rotation number detecting sensor by a calibration device. It is an object to provide a method and a rotation measuring device.

[0005]

A first embodiment of a rotation amount measuring method according to the present invention is a rotation amount measuring method for measuring a rotation amount such as a rotation position and a number of rotations of a rotation shaft of a motor. The physical quantity such as magnetic flux changes regularly with the rotation of the shaft, and the change of this physical quantity is converted into a signal change such as two voltages with different phases, and a signal waveform obtained by the converted signal change is obtained. When there is a deviation from the normal waveform, a correction process for eliminating the deviation is performed, and a rotation amount such as a rotation position and the number of rotations is calculated based on the corrected signal waveform.

In the first embodiment of the rotation amount measuring method according to the present invention, signal waveforms having different phases are, for example, a sin waveform and a cos waveform. A rotation amount such as the number of times is calculated.

[0007] sin (θ-α) = sin θ cos α-c
osθ sinα

Here, sin θ and cos θ indicate the respective converted signal waveform values, θ indicates the rotation amount,
α indicates a phase difference.

In the first embodiment of the rotation amount measuring method according to the present invention, when the deviation from the normal waveform is, for example, an offset, an offset equivalent is subtracted from the signal waveform converted to eliminate the offset, or This is performed by moving the coordinate axes by the offset.

In a second embodiment of the rotation amount measuring method according to the present invention, a physical quantity such as a magnetic flux changes regularly with the rotation of the rotating shaft of the motor, and the change of the physical quantity is determined by two voltages having different phases. This is a rotation amount measuring method for calculating the rotation amount such as the rotation position and the number of rotations of the rotation shaft of the motor based on the signal waveform obtained by the converted two signal changes. For each of the two signal waveforms obtained when rotated, a procedure for creating a signal waveform of a normal sine wave having one cycle between adjacent peaks or bottoms, and a phase difference between the two obtained signal waveforms A procedure for correcting the signal to have a predetermined value, and a corresponding relationship between the signal waveforms obtained when the motor is rotated at a constant speed and a signal waveform obtained when the phase difference is set to the predetermined value are obtained for each signal waveform. And correcting the signal waveform at the time of actual operation of the motor using the correspondence, and rotating the motor such as the rotational position and the number of rotations of the rotating shaft of the motor based on the corrected signal waveform at the time of actual operation of the motor. Calculating the amount.

The first embodiment and the second embodiment of the rotation amount measuring method of the present invention.
In an embodiment, it is preferable that a gain adjusting unit is provided, and when the gains or amplitudes of the two signal waveforms are different, processing for matching the gains or amplitudes of the two is performed.

A third embodiment of the rotation amount measuring method according to the present invention is such that a physical quantity such as a magnetic flux changes regularly with the rotation of a rotating shaft of a motor, and this change in the physical quantity is detected by two voltages having different phases. This is a rotation amount measurement method that measures the amount of rotation, such as the rotation position and the number of rotations, of the rotation axis of the motor using a signal waveform obtained by converting the signal change into a signal change such as that described above. Is stopped at the origin, the phase difference from the origin of the converted signal waveform at that time is calculated, and the calculated phase difference is subtracted from the converted voltage waveform at the time of actual operation to thereby obtain the position of the rotor from the origin. Is calculated, and the rotation amount such as the rotation position and the number of rotations of the rotating shaft of the motor is measured using the position.

On the other hand, the first embodiment of the rotation amount measuring apparatus according to the present invention is such that the physical amount such as magnetic flux changes regularly with the rotation of the rotating shaft of the motor, and the change of the physical amount is different in phase. A rotation amount measuring device that measures a rotation amount such as a rotation position and a number of rotations of a rotating shaft of a motor based on a signal waveform obtained by converting into a signal change of two voltages or the like. When there is a shift, a signal waveform correcting unit that eliminates the shift, and a rotation amount calculating unit that calculates a rotation amount such as a rotation position and the number of rotations using the signal waveform corrected by the signal waveform correcting unit are provided. It is characterized by becoming.

In the first embodiment of the rotation amount measuring apparatus according to the present invention, the signal waveforms having different phases are converted into a sine waveform and a cos waveform, and the rotation amount is calculated by obtaining α that makes the following equation zero. A rotation amount such as a position and the number of rotations is calculated.

Sin (θ-α) = sin θcosα-c
osθ sinα

Here, sin θ and cos θ indicate the converted signal waveform values, θ indicates the amount of rotation,
α indicates a phase difference.

In the first embodiment of the rotation amount measuring apparatus according to the present invention, when the deviation from the normal waveform is, for example, an offset, the elimination of the offset by the signal waveform correcting means is performed by an amount corresponding to the offset from the converted voltage waveform. Is subtracted, or the coordinate axis is moved by an offset.

A second embodiment of the rotation amount measuring device according to the present invention is such that a physical amount such as a magnetic flux changes regularly with the rotation of a rotating shaft of a motor, and the change of the physical amount is determined by two voltages having different phases. A rotation amount measuring device that calculates a rotation amount such as a rotation position and a number of rotations of a rotation axis of a motor based on two signal waveforms obtained by the converted signal change. Signal waveform creating means for creating a signal waveform of a normal sine wave having one cycle between adjacent peaks or bottoms for each of the two signal waveforms obtained when rotating at a high speed, and the obtained two signal waveforms Phase difference correcting means for correcting the phase difference to be a predetermined value, and a correspondence between the signal waveform having the predetermined phase difference and a signal waveform obtained when the motor is rotated at a constant speed. Ask for Relationship calculation means, actual operation waveform correction means for correcting the signal waveform during the actual operation of the motor using the correspondence, and the rotational position of the rotating shaft of the motor based on the corrected signal waveform during the actual operation of the motor. And a rotation amount calculating means for calculating a rotation amount such as the number of rotations and the number of rotations.

The first embodiment and the second embodiment of the rotation amount measuring device of the present invention.
In the embodiment, when the gain or the amplitude of the two signal waveforms is different, it is preferable to include a gain adjusting means for matching the gain or the amplitude of the two signal waveforms.

[0020]

Since the present invention is configured as described above, even if the converted signal waveform has a waveform distortion or a phase difference with respect to the normal waveform, the converted signal waveform has a phase difference with respect to the normal waveform. Since the rotation amount such as the rotation position and the number of rotations is calculated based on this, the accuracy of the measured rotation position such as the rotation position and the number of rotations is good even though the calibration is not performed by the calibration device.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments with reference to the accompanying drawings, but the present invention is not limited to only such embodiments.

A rotation amount measuring apparatus A according to an embodiment of the present invention.
Are shown in FIG. 1 and FIG. The rotation amount measuring device A includes a rotation number detection sensor (hereinafter simply referred to as a sensor) 10 for detecting a rotation amount such as a rotation position and the number of rotations of a servomotor (hereinafter simply referred to as a motor) M, and It comprises an arithmetic processing unit 20 for calculating the rotation amount of the motor M based on the detection signal and an apparatus main body 40 having an output unit 30 as main components.

The sensor 10 includes, for example, a gear 11 mounted so that its axis coincides with the rear end of the output shaft of the motor M, and a magnetic unit 12 disposed to face the gear 11. It is assumed. The tooth profile of the gear 11 is formed such that the voltage waveform obtained by the elements constituting the magnetoresistive element block 13 described later is approximately a sine wave. In the first embodiment, the number of teeth is equal to the number of electric cycles of the motor M per one rotation of the output shaft. For example, if the number of electric cycles of the motor M is 50, the number of teeth is set to 50.

The magnetic unit 12, as shown in FIG.
A permanent magnet 14 disposed with the magnetic pole facing the tooth surface of the gear 11, and a magnetoresistive disposed in front of the magnetic pole of the permanent magnet 14, that is, in parallel between the permanent magnet 14 and the gear 11. The element block 13 includes four electric resistance elements, that is, a first electric resistance element 13A, a second electric resistance element 13B, a third electric resistance element 13C, and a fourth electric resistance element 13D. You. These electric resistance elements 13A, 13B, 13C, and 13D have a conventionally known characteristic in which electric resistance changes in accordance with a change in a transmitted magnetic flux. Then, the first electric resistance element 1
The 3A to 4th electric resistance elements 13D are disposed, for example, such that the first electric resistance element 13A and the third electric resistance element 13C are located at the peaks and valleys of the gear teeth, while
The electric resistance element 13B and the fourth electric resistance element 13D
The first and third electric resistance elements 13A and 13C are disposed so as to be shifted from each other by a quarter pitch of the gear (see FIG. 3).

FIG. 2 is a circuit diagram constituted by using the first to fourth electric resistance elements 13A to 13D, and is connected to form a bridge circuit as shown. That is constituted by R _a, a first bridge constructed by the main route and R _1, consisting of R ₃ pathway consists R _b, consisting of R _a, main route consists R _b and R _2, R ₄ path Are connected so as to form a second bridge. In FIG. 2, reference characters R ₁ , R ₂ , R _3, and R ₄ denote equivalent resistances of the first electric resistance element 13A, the second electric resistance element 13B, the third electric resistance element 13C, and the fourth electric resistance element 13D, respectively. , R _a and R _b denote the resistance of the main path, and V ₁ and V ₂ denote a first voltmeter and a second voltmeter, respectively. In the first embodiment, R
_a = _Rb .

The arithmetic processing unit 20 includes a signal waveform correcting unit 2
1. It is provided with a rotation amount calculating means 22 and the like.

The signal waveform correcting means 21 includes a first voltmeter V ₁
And if the second voltmeter V ₂ by the resulting voltage waveform, and the like deviated from a normal waveform, first voltmeter V ₁ and second voltmeter V ₂ by the resulting voltage waveform by eliminating such the deviation Has a function of performing processing such as matching a signal with a normal waveform, and includes a gain adjusting unit 211, an offset eliminating unit 212, a signal waveform creating unit 213, a phase difference correcting unit 214, a correspondence calculating unit 215, and a waveform during actual operation. It is provided with correction means 216 and the like.

The gain adjusting means 211 includes a first voltmeter V ₁
And when the gain (amplitude) G is different in the second voltmeter V ₂ by the resulting voltage waveform, it has a function of forming a process of matching both the gain (amplitude) G.

The offset eliminating means 212, if the first voltmeter V ₁ and the voltage waveform obtained by the second voltmeter V ₂ is offset, has a function of forming a process to eliminate the offset.

The signal waveform creating means 213 is provided with a first voltmeter V
₁ and two adjacent second voltmeter V ₂ by the resulting voltage waveform
It has a function of creating a normal sine wave from two peak values or bottom values.

The phase difference correction means 214 is provided with a first voltmeter V ₁
And when the phase difference between the second voltmeter V ₂ by the resulting voltage waveform is not a predetermined value, for example if not 90 degrees, the phase difference between the first voltmeter V ₁ and second voltmeter V ₂ by the resulting voltage waveform Is set to a predetermined value, for example, 90 degrees.

The correspondence calculating means 215 is provided with the first voltmeter V
A voltage waveform obtained by _one or the second voltmeter V _2, and has a function of calculating the correspondence between the order to match the regular sine wave created by the signal waveform creation unit 213.
Then, the calculated correspondence is stored in the form of a table or a function.

The waveform correction means 216 during actual operation includes the motor M
A first voltmeter V ₁ and the voltage waveform obtained by the second voltmeter V ₂ during actual operation, and has a function of correcting the correspondence obtained by the correspondence relation calculating means 215.

The rotation amount calculating means 22 uses the voltage waveform values of the first voltmeter V ₁ and the second voltmeter V ₂ corrected by the signal waveform correcting means 21 to determine the rotational position and rotation of the rotating shaft of the motor M. It has a function of calculating the rotation amount such as the number of times. The specific calculation method will be described later.

The arithmetic processing unit 20 provided with each of the above means
Specifically, the A / D converter, RA
M, a ROM, a clock, an input / output interface, and the like. The ROM includes a gain adjusting unit 211, an offset eliminating unit 212, a signal waveform creating unit 213, A program corresponding to the phase difference correction means 214, the correspondence relation calculation means 215, the actual operation waveform correction means 216, and the like, a program corresponding to the rotation amount calculation means 22, and other necessary programs are stored. The detection signal from 10 is converted to a digital value and stored temporarily. The exchange of signals between the sensor 10 and the arithmetic processing unit 20 is performed via an input / output interface.

Next, the measurement of the rotation position of the motor M by the rotation amount measuring device A having such a configuration will be described with reference to FIG.
The description will be made on the assumption that the measurement is started from a state where the bridge is in equilibrium.

(1) When the motor M is rotated, the distance between the first electric resistance element 13A, the second electric resistance element 13B, the third electric resistance element 13C, the fourth electric resistance element 13D and the teeth of the gear 11 changes. Therefore, the first electric resistance element 13A,
The magnetic flux passing through the second electric resistance element 13B, the third electric resistance element 13C, and the fourth electric resistance element 13D changes.

(2) When the magnetic flux passing through the first electric resistance element 13A, the second electric resistance element 13B, the third electric resistance element 13C, and the fourth electric resistance element 13D changes, the first electric resistance element 13A, The resistance values of the electric resistance element 13B, the third electric resistance element 13C, and the fourth electric resistance element 13D change, and the balance of the first bridge is lost, and the first voltmeter V ₁
Optionally with the voltage is detected, the state of the second bridge varies, the voltage also changes, which is detected by the second voltmeter V _2.

(3) The voltages detected by the first voltmeter V ₁ and the second voltmeter V ₂ are sent to the arithmetic processing unit 20. Voltage detected by the first voltmeter V ₁ and second voltmeter V ₂ as described above exhibits a sinusoidal waveform (see FIG. 4). For example, the voltage waveform from the first voltmeter V ₁ is if the sin-like waveform, the voltage waveform from the second voltmeter V ₂ becomes cos shaped waveform.

(4) The arithmetic processing unit 20 converts the analog voltage waveform input from the sensor 10 into a digital value by the A / D converter and stores the digital value in the RAM.

(5) The CPU converts the first voltmeter V which is converted into a digital value by the A / D converter and stored in the RAM.
And calculates the rotation amount, such as rotational position and the rotational number by a method described later from the voltage waveform value from the voltage waveform value and a second voltmeter V ₂ from _1. In calculating the amount of rotation, if one wavelength of the voltage waveform is represented by 8 bits, for example, the number of teeth of the gear 11 is set to 50 as described above.
The resolution of the rotation amount measuring device A is 1 / (50 × 25
6) = 1/12800.

The rotation amount thus calculated is sent from the arithmetic processing unit 20 to the output unit 30, and is used as, for example, a feedback value for motor control.

[0043] Next, a method for calculating the rotational position based on the voltage waveform value from the voltage waveform value and a second voltmeter V ₂ from the first voltmeter V ₁ by the rotation amount calculating unit 22.

Assuming that the rotational position is θ and the phase difference is α, a relation of sin (θ−α) = sin θ cos α−cos θ sin α (1) is obtained from a well-known trigonometric function formula.

In the above equation (1), sin θ is known from the voltage waveform value from the first voltmeter V ₁ , and cos
Since θ is known from the voltage waveform value of the second voltmeter V ₂ ,
If α is set to an appropriate value, the value of sin (θ−α) can be obtained. If α is determined by convergence calculation so that the value of sin (θ−α) becomes zero, the value of (θ−α) at that time also becomes zero. Therefore, α at that time
Gives θ, that is, the rotational position.

[0046] However, only when the amount of rotation of the rotary shaft by the above-described procedure that can be calculated, it is not an error in the voltage waveform value and the second voltage waveform voltmeter V ₂ from the first voltmeter V ₁ . In the usual case, it contains an error in the voltage waveform value and the voltage waveform value of the second voltmeter V ₂ from the first voltmeter V ₁ due to various factors. That is, the voltage waveform and a second voltage waveform of the voltage meter V ₂ from the first voltmeter V _1, has a waveform which is shifted from the normal sine wave. For example, Toka to first voltmeter V ₁ and the voltage waveform obtained by the second voltmeter V ₂ is the waveform distortion measured, Toka offset the resulting voltage waveform δ is present, the first voltmeter V ₁ gain of the voltage waveform and the second voltmeter V ₂ voltage waveform (amplitude) G occurs may like or something not match. Therefore, the value of α calculated by the equation (1) is a value α'deviated from the true value by using a voltage waveform value and the second voltage waveform voltmeter V ₂ from the first voltmeter V ₁ . For example, the gain of the voltage waveform values measured by the first voltmeter V ₁ (amplitude) is ₁ offset δ in G _1, the gain of the voltage waveform value measured by the second voltmeter V ₂ (amplitude) Assuming that the offset is δ ₂ at G ₂ , the right side of the above equation (1) is as follows.

Right side = (δ ₁ + G ₁ sin θ) cos α− (δ ₂ + G ₂ cos θ) sin α (2)

For this reason, in this embodiment, the signal waveform correcting means 21 performs processing for eliminating those effects, that is, signal waveform value correction processing. This is done as follows.

A. Gain (amplitude) for each obtained voltage waveform
In this case, the following processing is performed to calculate the rotational position.

[0050] First, to calculate the gain (amplitude) G ₁ and the offset [delta] ₁ maximum and minimum first voltmeter than value V ₁ of the measured voltage waveform value by a first voltmeter V _1. First voltmeter V ₁ of the gain (amplitude) G ₁ is obtained from the half of the difference between the offset [delta] ₁ of the first voltmeter V ₁ was the sum of both 1/2
More obtained, a second voltmeter V ₂ gain (amplitude) G ₂ is a second
Obtained from a half of the difference between the maximum value and the minimum value of the voltage waveform value measured by the voltmeter V _2, the offset [delta] ₂ of the second voltmeter V ₂ is obtained than half the sum of both.

Then, the gain (amplitude) of the first voltmeter V ₁
The processing by the gain adjusting unit 211 as G ₁ and a second voltmeter V ₂ gain (amplitude) G ₂ are identical. For example, the gain (amplitude) G ₂ of the second voltmeter V ₂ is
Or to match the _first gain (amplitude) G _1, or first voltmeter V ₁ of the gain (amplitude) G ₁ is matched second voltmeter V ₂ gain (amplitude) in G ₂ Conversely, or the first the gain G ₁ and the second voltmeter V ₂ of the gain of the voltmeter V ₁ (amplitude) G ₂ first
Or the gain of the voltmeter V ₁ (amplitude) G ₁ and a second voltmeter V ₂ gain (amplitude) Mean value of _{G 2 ((G 1 + G} 2) / 2).

Next, the first voltmeter V ₁ and the second voltmeter V ₂ are set so that the obtained offset δ ₁ of the voltage waveform of the first voltmeter V ₁ and the offset δ ₂ of the voltage waveform of the second voltmeter V ₂ become zero. offset eliminating means for each measurement value of the voltmeter V ₂ 2
The processing is performed by 12. For example, the offset [delta] ₁ is subtracted from the voltage waveform values measured by the first voltmeter V _1, subtracting the offset [delta] ₂ from the voltage waveform value measured by the second voltmeter V _2. In this case, the offset δ may be removed by moving the coordinate axes of each voltage waveform so that the offsets δ ₁ and δ ₂ become zero.

When such processing is performed, if the gain (amplitude) is G, the above equation (2) can be transformed into the following equation.

Right side = G (sin θ cos α−cos θ sin α) (3) As is apparent from the above equation (3), the parentheses in the equation (3) coincide with the right side of the equation (1). Therefore, if α is determined so that the value in the parentheses of the equation (3) is zero, the α gives θ. That is, the rotational position is calculated.

As described above, by performing the above-described processing, the voltage waveform value measured by the first voltmeter V ₁ and the voltage waveform value measured by the second voltmeter V ₂ have an offset δ, Even if the gain (amplitude) G of the rotation axis is different, the rotation position of the rotation shaft can be calculated with high accuracy.

B. Processing when the obtained voltage waveform has waveform distortion In this case, the following processing is performed to calculate the rotational position.

[0057] (1) is rotated at a constant speed motor M without load, measuring a first voltmeter V ₁ of the voltage waveform and a second voltmeter V ₂ voltage waveform in this state. For example,
Be such as shown by the solid line, also the second voltage waveform of the voltage meter V ₂ diagram of a first voltmeter V ₁ of the voltage waveform in FIG. 5 (a) 5
It is assumed that it is as shown by the solid line in (b). In FIGS. 5A and 5B, the vertical axis indicates voltage output, and the horizontal axis indicates time. In this case, since the motor M is rotated at a constant speed, the horizontal axis is proportional to the rotation angle. In FIGS. 5A and 5B, the waveform distortion is exaggerated for convenience of explanation.

(2) In FIG. 5A, a sine wave having one cycle between arbitrary adjacent peaks, for example, between P _a1 and P _a2, and having an amplitude of 差 of the difference between the peak value and the bottom value. (G ₁ sin θ) is created by the signal waveform creation means 213. This is shown by the dotted line in FIG. Similarly, the sine wave (G ₁ sin θ) having an amplitude of 差 of the difference between the peak value and the bottom value in FIG. 5B and the sine wave (G ₂ cos θ) shifted in phase by 90 degrees are signal waveforms. Creation means 21
3 This is shown by the dotted line in FIG.

(3) The voltage waveform of the first voltmeter V _{1 and} the voltage waveform of the second voltmeter V ₂ are each represented by a sine wave (G ₁ sin).
θ) and a sine wave (G ₂ cos θ) are created by the correspondence calculating means 215.

[0060] (4) The obtained conversion table or conversion expression in any of the first voltage waveform voltmeter V ₁ and the second voltage waveform voltmeter V ₂ times during actual operation (3) using The sine wave (G
₁ sin θ) and the value of a sine wave (G ₂ cos θ). This conversion is performed as contradictory positive and negative of the combination of the first voltage waveform voltmeter V ₁ and the second voltage waveform voltmeter V ₂ does not occur.

[0061] (5) (4) by dividing the corrected first voltmeter V ₁ of the voltage waveform value and a second voltmeter V ₂ voltage waveform values each gain (amplitude) by, i.e. is modified The voltage waveform value of the first voltmeter V ₁ is divided by the gain (amplitude) G ₁ to obtain a value of sin θ, and the corrected second voltmeter V ₂
Divided by the gain (amplitude) G ₂ to obtain cos
Get the value of θ.

It should be noted that the data during the actual operation of the motor M is corrected using the data obtained in the no-load state because the voltage waveforms detected by the first voltmeter V ₁ and the second voltmeter V ₂ are corrected. Since the distortion is mainly caused by the characteristics of the electric resistance elements 13A to 13D and the structure of the rotation speed sensor 10, they hardly change with time, and by performing the processing on the voltage waveform at the time of actual operation, This is because the obtained voltage waveform can be made a regular voltage waveform.

Thus, α, that is, θ is calculated by convergence calculation using sin θ and cos θ obtained by the rotation amount calculating means 22.

The sin calculated by the above (5)
A table for calculating θ from θ and cos θ is created by the rotation amount calculating means 22 and θ
May be calculated directly. In this case, from the viewpoint of improving the calculation accuracy, when θ is in the range of 0 ° to 45 °, θ is calculated from the value of sin θ, and θ is 45 ° to 1 °.
When the angle is in the range of 35 degrees, θ is calculated based on the value of cos θ. When the angle θ is in the range of 135 degrees to 225 degrees, sin is calculated.
θ is calculated based on the value of θ, and when θ is in the range of 225 degrees to 315 degrees, θ is calculated based on the value of cos θ.
When the angle is in the range of 13 degrees to 360 degrees, it is preferable to calculate θ based on the value of sin θ.

As described above, by performing the above-described processing, even if the voltage waveform measured by the first voltmeter V ₁ and the voltage waveform measured by the second voltmeter V ₂ are distorted, the rotation is accurately performed. The rotational position of the shaft can be calculated.

C. When there is a phase difference in the obtained voltage waveform In this case, the rotational position is calculated as follows.

(1) No load is applied to the motor M during the initial adjustment.

(2) The rotor is stopped at the origin, and the phase difference from the origin of each voltage waveform measured by the first voltmeter V ₁ and the second voltmeter V ₂ at that time is calculated.

(3) The phase difference is subtracted from the respective voltage waveforms obtained by the _first and second voltmeters V ₁ and V ₂ by the phase difference correction means 214 during actual operation, and the phase of each voltage waveform value is calculated. And the position of the rotor from the origin is calculated using the corrected voltage waveforms.

(4) The rotation amount is calculated by the rotation amount calculation means 22 using the calculated deviation from the origin position of the rotor.

The reason why the data during the actual operation of the motor M is corrected using the data obtained in the no-load state is that the phase difference mainly depends on the characteristics of the electric resistance elements 13A to 13D and the rotation amount detection sensor 10. Due to the structure, they hardly change over time, and the voltage waveform obtained during actual operation can be processed to make the obtained voltage waveform a normal voltage waveform.

As described above, by performing the above-described processing, even if each of the voltage waveforms of the first voltmeter V ₁ and the second voltmeter V _{2 has} a phase shift with respect to the waveform of the normal sine wave, The rotation position of the rotation shaft can be calculated accurately.

The present invention has been described based on the embodiments. However, the present invention is not limited to the embodiments, and various modifications can be made. For example, in the embodiment, a change in magnetic flux is converted into a change in voltage. However, the detected physical quantity is not limited to the magnetic flux alone, and may be another physical quantity, such as electromotive force, electric resistance, and electric resistance. It may be a capacity, a light amount, or the like. Further, the conversion form of the detected change in the physical quantity is not limited to the voltage change, but may be another signal form, for example, a current change, a frequency change, or the like.

[0074]

As described above in detail, according to the present invention, it is assumed that the signal waveform obtained by the first detector and the second detector constituting the sensor has waveform distortion due to various factors. Also, an excellent effect that the amount of rotation of the rotating shaft can be accurately calculated can be obtained.

Further, since it is not necessary to calibrate the sensor by the calibration device, an excellent effect that the operation rate of the motor is improved can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of a rotation amount measuring device according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of an electrical configuration of a rotation amount measuring device according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of a positional relationship between a magnetoresistive element and gear teeth.

FIG. 4 is a graph schematically showing voltage waveforms detected by a first bridge and a second bridge.

5A and 5B are graphs schematically showing a measured voltage waveform, wherein FIG. 5A shows a voltage waveform obtained by a first voltmeter, and FIG. 5B shows a voltage waveform obtained by a second voltmeter. .

FIG. 6 is a schematic view of a motor provided with a rotation speed detector.

FIG. 7 is a schematic view of a conventional calibration device for a rotational speed detector.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 rotation speed detection sensor 11 gear 12 magnetic unit 13 magnetic resistance element block 13A first electric resistance element 13B second electric resistance element 13C third electric resistance element 13D fourth electric resistance element 14 permanent magnet 20 arithmetic processing unit 21 signal waveform correction Means 22 Rotation amount calculation means 30 Output unit 40 Device body A Rotation amount detection device M Servo motor

Claims (11)

[Claims] 1. A rotation amount measuring method for measuring a rotation amount such as a rotation position and the number of rotations of a rotation shaft of a motor, wherein a physical quantity such as a magnetic flux changes regularly with rotation of the rotation shaft of the motor. Then, this change in physical quantity is converted into a signal change such as two voltages having different phases, and if a signal waveform obtained by the converted signal change has a deviation from a normal waveform, a correction process for eliminating the deviation is performed. A rotation amount such as a rotation position and the number of rotations is calculated based on the corrected signal waveform. 2. The method according to claim 1, wherein the signal waveforms having different phases are a sin waveform and a cos waveform, and a rotation amount such as a rotation position and the number of rotations is calculated by obtaining α that makes the following equation zero. The rotation amount measuring method according to claim 1. sin (θ−α) = sin θcosα−cosθsin
α Here, sin θ and cos θ indicate converted signal waveform values, θ indicates a rotation amount, and α indicates a phase difference. 3. The offset from the normal waveform is an offset, and the offset is eliminated by subtracting an offset equivalent from the obtained signal waveform or by moving a coordinate axis by the offset. 3. The method for measuring the amount of rotation according to claim 1, wherein 4. A physical quantity such as a magnetic flux is regularly changed with rotation of a rotating shaft of a motor, and the change of the physical quantity is converted into a signal change such as two voltages having different phases. A rotation amount measuring method for calculating a rotation amount such as a rotation position and a number of rotations of a rotation shaft of a motor based on signal waveforms obtained by two signal changes, wherein the two signals obtained when the motor is rotated at a constant speed. For each of the waveforms, a procedure for creating a signal waveform of a normal sine wave having one cycle between adjacent peaks or bottoms, and a procedure for correcting a phase difference between two obtained signal waveforms to be a predetermined value. A procedure for obtaining the corresponding relationship between each of the signal waveforms from the signal waveform having the phase difference of a predetermined value and the signal waveform obtained when the motor is rotated at a constant speed. Correcting the signal waveform using the correspondence relationship, and calculating the rotation amount such as the rotation position and the number of rotations of the rotating shaft of the motor based on the corrected signal waveform at the time of actual operation of the motor. A rotation amount measuring method. 5. The rotation amount measuring method according to claim 2, further comprising a step of, when the gains or amplitudes of the two signal waveforms are different from each other, performing a process for matching the gains or amplitudes of the two signal waveforms. . 6. A physical quantity such as a magnetic flux is regularly changed with the rotation of a rotating shaft of a motor, and the change in the physical quantity is converted into a signal change such as two voltages having different phases. This is a rotation amount measurement method that measures the rotation amount such as the rotation position and the number of rotations of the rotation axis of the motor using a signal waveform.The rotor is stopped at the home position with the motor unloaded during the initial adjustment, and the conversion at that time is performed. Calculate the phase difference from the origin of the signal waveform obtained by the signal change, and calculate the position of the rotor from the origin by subtracting the calculated phase difference from the signal waveform obtained during actual operation, A rotation amount measuring method characterized by measuring a rotation amount such as a rotation position and a number of rotations of a rotation shaft of a motor using the position. 7. A physical quantity such as a magnetic flux is regularly changed with the rotation of a rotating shaft of a motor, and a change in the physical quantity is converted into a signal change such as two voltages having different phases. A rotation amount measuring device that measures the amount of rotation such as the rotation position and the number of rotations of the rotation axis of a motor using a signal waveform. If the obtained signal waveform has a deviation from the normal waveform, a signal waveform that eliminates the deviation A rotation amount measuring apparatus comprising: a correction unit; and a rotation amount calculation unit that calculates a rotation amount such as a rotation position and a number of rotations using the signal waveform corrected by the signal waveform correction unit. 8. A signal waveform having a different phase is a sin waveform and a cos waveform, and a rotation amount such as a rotation position and the number of rotations is calculated by obtaining α that makes the following equation zero by a rotation amount calculation means. The rotation amount measuring device according to claim 7, wherein: sin (θ−α) = sin θcosα−cosθsin
α Here, sin θ and cos θ indicate converted signal waveform values, θ indicates a rotation amount, and α indicates a phase difference. 9. The offset from the normal waveform is an offset, and the offset is eliminated by the signal waveform correcting means.
9. The rotation amount measuring apparatus according to claim 7, wherein the rotation amount is measured by subtracting an amount corresponding to the offset from the obtained signal waveform, or by moving a coordinate axis by the amount corresponding to the offset. 10. A physical quantity such as a magnetic flux is regularly changed with rotation of a rotating shaft of a motor, and a change in the physical quantity is converted into a signal change such as two voltages having different phases. A rotation amount measuring device that calculates a rotation amount such as a rotation position and a number of rotations of a rotation shaft of a motor based on signal waveforms obtained by two signal changes, wherein the two signals obtained when the motor is rotated at a constant speed. Signal waveform generating means for generating a signal waveform of a normal sine wave having one cycle between adjacent peaks or bottoms for each waveform; and correcting the phase difference between the two obtained signal waveforms to a predetermined value. A phase difference correction unit that calculates a corresponding relationship between the signal waveform in which the phase difference has a predetermined value and a signal waveform obtained when the motor is rotated at a constant speed; An actual operation waveform correction means for correcting the signal waveform at the time using the correspondence relationship; and calculating the rotation amount such as the rotation position and the number of rotations of the rotating shaft of the motor based on the corrected signal waveform at the time of the actual operation of the motor. And a rotation amount calculating means. 11. The rotation amount measuring device according to claim 8, further comprising a gain adjustment unit that matches the gain or the amplitude of the two signal waveforms when the two signal waveforms have different gains or amplitudes.