JPH0658766A - Absolute position detector and motor control apparatus - Google Patents

Abstract

PURPOSE:To obtain a compact absolute position detector having the simple constitution and high resolution by using a magnetic recording medium and magnetoresistance effect elements and to obtain a motor control apparatus by using the absolute position detector. CONSTITUTION:Tracks T1 and T2, wherein a plurality of magnetic signals are recorded, are provided in a moving magnetic recording medium 1. Magnetic signals NS at a pitch lambda1 are continuously recorded on the first track T1. Magnetic signals NS at a pitch lambda2 are continuously recorded on the second track T2. A magnetism sensor 2 is arranged so as to face the magnetic recording medium 1. The magnetism sensor 2 has a first magnetoresistance effect element R11 and a second magnetoresistance effect element R21. The absolute position of a moving body is detected based on the phase difference between two sets of the output signals obtained with the magnetoresistance effect elements. The highly accurate controllability is obtained with a motor control apparatus using this absolute position detector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for magnetically detecting a position, and more particularly to an absolute position detecting apparatus using a plurality of magnetic recording media suitable for position control and a plurality of magnetoresistive effect elements and its application. Is. In particular, it is widely used in the field of servo control, for example.

[0002]

2. Description of the Related Art A conventional position detecting device comprises a magnetic recording medium having a magnetically recorded magnetic signal and a magnetic detecting element arranged so as to face a track of the magnetic recording medium. The position of the moving body is detected based on the detection signal. In the position detecting device having such a configuration, it is necessary to make the required number of magnetic recording units continuous in the moving direction of the moving body. That is, the recording length of the magnetic recording signal is substantially equal to the number of bits of the output signal because the required number of magnetic poles N and S of the minimum magnetic recording unit are continuously recorded in each track in the moving direction of the track. Tracks and magnetic sensors were used. That is, in the case of 8 bits that can obtain a resolution of 256, eight or more tracks and magnetic sensors were used. Therefore, the position detection device has a drawback that the structure is complicated, its shape is large, and miniaturization is difficult. As a technique related to this, for example, the technique described in JP-A-61-17011 is known. Further, the motor control device having the above-mentioned conventional position detecting device as a constituent element has a drawback that the structure is complicated and a large installation area is required.

[0003]

As described above, the above-mentioned conventional position detecting device uses the magnetic track and the magnetic sensor whose number of bits of the output signal is almost equal to each other, and moreover, the magnetoresistive effect constituting the magnetic sensor. The element has an anisotropic shape in which one direction is very long (hereinafter, referred to as a longitudinal direction) and the other direction (hereinafter, referred to as a width direction) has an anisotropic shape to provide magnetoresistance.

Since a required number of the anisotropically shaped elements are arranged in the longitudinal direction, there is a problem that the structure is complicated, the shape is large, and miniaturization is difficult. Further, the motor control device using this absolute position detection device also has a problem that the structure is complicated and its shape becomes large.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and it is a first object of the present invention to provide an absolute position detecting device having a simplified structure, a small size, and high resolution. The purpose of. A second object of the present invention is to provide a high precision mode using the high resolution absolute position detecting device.
To provide a control device.

[0006]

In order to achieve the first object, an absolute position detecting device according to the present invention has a magnetic recording medium having a magnetic signal NS recorded on a moving body or a fixed body. In the position detection device for detecting the position of the moving body, the magnetic recording medium is divided into two tracks, N magnetic signals (n; even number) are recorded on each track, and (n ± 2) magnetic signals are recorded on the second track, and the magnetic sensor is composed of two sets of magnetoresistive element groups. The first set of magnetoresistive effect element groups is arranged so as to face the first track, and the second set of magnetoresistive effect element groups is arranged so as to face the second track. Obtained from the output of the resistive element group Is obtained so as to obtain the absolute position of the moving body from the phase difference between the second electrical angle θ2, which is obtained from the output of the first electrical angle θ1 and said two sets of magneto-resistive element group.

The above-mentioned two tracks may be composed of first, second and third tracks, and n magnetic signals (n; even number) may be m (m; integer) magnetic signals. . That is, basically, the tracks of the magnetic recording medium for recording the magnetic signals are set to 2 to 3 tracks, and the numbers of the magnetic signals to be recorded on the respective tracks are made different. The absolute position of the moving body is detected by utilizing the fact that the outputs of the two to three sets of magnetic sensors arranged facing this track have different electrical phases depending on the position of each track. It was done like this. Further, the absolute position of the moving body is detected by using the signal obtained from the two tracks and the signal obtained from the one track to improve the resolution.

In order to achieve the above second object,
The configuration of a motor control device according to the present invention is a motor control device including a control motor for driving a device and a position detector for detecting the position of the motor, wherein the absolute position detection device is used for the position detector. It was what I had.

[0009]

The operation of each of the above technical means is as follows. According to the configuration of the first invention, tracks for recording magnetic signals on the magnetic recording medium attached to the moving body are divided into 2 to 3, and n tracks (n; even number) or m tracks (m) are provided on the first track. (Integer) magnetic signal is recorded and (n ±) is recorded on the second track.
2) or (m ± 1) magnetic signals are recorded, and the magnetic sensors composed of a plurality of magnetoresistive elements facing the track are provided, so that an output electric signal can be obtained from these magnetic sensors. .

Since these output electric signals have different numbers of magnetic signals recorded on the tracks, the cycle of resistance change of the magnetoresistive effect element is different, and therefore the cycle of the electric signal is also different. Therefore, the electrical angle of the electrical output signal of the magnetoresistive element facing the first track and the second angle
The absolute position of the moving body is detected by the phase difference from the electrical angle of the electrical output signal of the magnetoresistive element facing the track.

Further, when the third track is provided, the output signal of the magnetoresistive effect element of the magnetic sensor facing the third track and the magnetoresistive effect of the magnetic sensor facing the first and second tracks. From the combination with the output signal of the element,
It is possible to obtain the absolute position of the moving body with high resolution.

Further, since the respective positions of the plurality of magnetoresistive effect elements of the magnetic sensor are arranged so as to be electrically displaced, the phase difference of the output signal based on the displacement of the positions and the combination thereof are used to estimate the coarseness of the moving body. By detecting the position and the fine position, it is possible to obtain the absolute position of the moving body with higher resolution.

Further, according to the structure of the second invention, in the motor control device provided with the control motor for driving the device and the position detector for detecting the position of the motor, the position detector has the first invention. Since this absolute position detecting device is used, it is possible to input a more accurate position signal than this absolute position detecting device and perform highly accurate motor control.

[0014]

Embodiments of the present invention will now be described with reference to FIGS. 1 to 21.
Will be described with reference to. [Embodiment 1] FIG. 1 is a basic configuration diagram of a rotary absolute position detecting device according to an embodiment of the present invention, FIG. 2 is a signal magnetic field characteristic diagram of a magnetoresistive effect element in the device of FIG. 1, and FIG. 4 is a development view of a rotary absolute position detection device according to one embodiment of the present invention.
Is an output waveform diagram of the magnetoresistive effect element in the device of FIG.
FIG. 5 is a diagram showing the relationship between the rotational position of the moving body and the phase difference of the output of the magnetoresistive effect element in the apparatus of FIG.

In FIG. 1, 1 is a magnetic drum which is a magnetic recording medium, 2 is a magnetic sensor, and 3 is a rotating shaft of the magnetic drum. The magnetic drum 1 is attached to a rotating shaft 3 and can rotate about this shaft 3. Magnetic drum 1
Two magnetic tracks T1 and T2 are provided on the surface of the magnetic recording medium, and a magnetic signal NS having a pitch λ1 is continuously recorded on the first track T1 and a magnetic signal NS having a pitch λ2 is continuously recorded on the second track T2. Further, a magnetic sensor 2 is arranged to face the magnetic drum 1, and the magnetic sensor 2 further includes a first magnetoresistive effect element R11 and a second magnetoresistive effect element R21. There is. Magnetoresistive element R1
1, R21 are formed of a thin film of a ferromagnetic material such as permalloy, and have a characteristic that the electric resistance of the element changes with an applied magnetic field.

Next, the function of the absolute position detecting device according to the embodiment of the present invention having the above-mentioned structure will be described. When the magnetic drum 1 rotates about the rotating shaft 3, the magnetoresistive effect element R1
1, the magnetic field applied to R21 changes depending on the position of the magnetic drum 1. When the magnetic field changes depending on the position, the resistance of the elements R11 and R21 changes due to its magnetoresistive effect characteristic. Therefore, conversely, the element R11,
By knowing the resistance of R21, the rotational position of the magnetic drum 1 can be known.

More specifically, the characteristics of the magnetoresistive effect elements R11 and R21 with respect to the signal magnetic field are inversely proportional to the square of the magnitude of the magnetic field regardless of whether the magnetic field is positive or negative as shown in FIG. The resistance change is saturated in a certain magnetic field. Now, when the magnetic drum 1 rotates, the magnetic fields applied to the magnetoresistive effect elements R11 and R21 change sinusoidally, so that the resistance changes corresponding to 1 to 3 in FIG. The resistance changes of the magnetoresistive effect elements R11 and R21 are obtained for two cycles.

Since the number of magnetic signals on the track T1 of the magnetic drum 1 is different from the number of magnetic signals on the track T2, the resistance change of the magnetoresistive effect element R11 to which the magnetic signal of the track T1 is applied and the track T2. The electrical cycle of the resistance change of the magnetoresistive effect element R21 to which the magnetic signal is applied is different. This means that the electrical angle of the sine wave output, which is the resistance change of the magnetoresistive effect elements R11 and R21, differs depending on the position of the magnetic drum 1. Therefore, the absolute position of the magnetic drum 1 can be obtained by detecting the difference between the electrical angles of the sine wave outputs of the magnetoresistive effect elements R11 and R21, that is, the phase difference.

FIG. 3 is a development view illustrating the above principle in more detail. In FIG. 3, reference numeral 1A is a magnetic recording medium, and the magnetic drum 1 is shown in a developed state for the sake of clarity. 2A is a magnetic sensor. As shown in the figure, ten magnetic signals having a pitch λ1 are recorded on the first track T1 of the magnetic recording medium 1A, and the pitch λ is recorded on the second track T2.
12 magnetic signals of 2 are recorded. That is, on the first track T1, n magnetic signals (n;
(Even number) is recorded, and (n ± 2) magnetic signals having a pitch λ2 are recorded on the second track T2.

The magnetic sensor 2A has two magnetoresistive elements.
Two sets are provided, the first set is the magnetoresistive effect elements R11 and R12, and the second set is the magnetoresistive effect elements R21 and R22, which are arranged at intervals of λ1 / 4 and λ2 / 4, respectively. . λ
Since the relationship between 1 and λ2 is λ2 = λ1 {n / (n ± 2)}, the second set of magnetoresistive effect elements R21 and R2
The intervals of 2 are arranged at intervals of λ1 {n / (n ± 2)} / 4.

When the magnetic drum 1 rotates, the magnetic recording medium 1
When the relative position between A and the magnetic sensor 2A changes, the magnetic fields for the magnetoresistive effect elements R11 and R21 also change, and the outputs thereof have the waveforms sin1 and sin2 shown in FIG. Figure 4
The waveform of indicates that the magnetic drum 1 returns to its original position after one rotation. Further, the magnetoresistive effect elements R12 and R2
The outputs of 2 are each delayed by 90 degrees in electrical angle from the waveform of FIG. 4, that is, delayed by (λ1 / 4) and (λ2 / 4).

Here, comparing the output waveform sin1 of the magnetoresistive effect element R11 and the output waveform sin2 of R21, the phases of both waveforms are initially the same. Next, when rotating in the direction indicated by the arrow, the phase of sin2 advances from the phase of sin1, and the phase difference increases corresponding to the rotation, and eventually the first half rotation becomes the same phase, and the latter half rotation becomes the first half rotation. The same thing as half a turn is repeated. FIG. 5 shows the relationship between the rotational position of the magnetic drum 1, that is, the position of the magnetic recording medium 1A and the phase difference between the two waveforms. Therefore, by comparing the phase difference between sin1 and sin2,
The absolute position of half rotation of the magnetic drum 1 can be detected. As described above, according to the present embodiment, it is possible to detect the absolute position of the magnetic drum 1, which is a moving body, with a simple configuration and with high accuracy.

[Second Embodiment] Next, another embodiment of the present invention will be described. 6 is a development view of a rotary absolute position detecting device according to another embodiment of the present invention, FIG. 7 is a signal magnetic field characteristic diagram of a magnetoresistive effect element in the device of FIG. 6, and FIG. 8 is a magnetic resistance in the device of FIG. FIG. 9 is a diagram showing the output waveform of the effect element, and FIG. 9 is a diagram showing the relationship between the rotational position of the moving body and the phase difference of the magnetoresistive effect element output waveform in the apparatus of FIG.

In FIG. 6, a rotary type absolute position detecting device according to another embodiment of the first invention is shown in FIG.
The configuration is almost the same as in 1). 1B is a magnetic recording medium having the same structure as the magnetic recording medium 1A of [Example 1],
B is a magnetic sensor having the same configuration as the magnetic sensor 1A of [Example 1], but a bias magnetic field Hb shown by the arrow in FIG. 6 is applied. Next, the operation of this embodiment will be described. The characteristics of the magnetoresistive effect element with respect to the signal magnetic field Hs are as shown in FIG. 7, and one cycle of the change in resistance of the magnetoresistive effect element can be obtained with respect to the change of one cycle of the magnetic signal of the track on the magnetic recording medium 1. . In the rotary absolute position detector shown in FIG. 6, ten magnetic signals having a pitch λ1 are recorded on the first track T1 of the magnetic recording medium 1B, and twelve magnetic signals having a pitch λ2 are recorded on the second track T2. It is recorded.

The magnetic sensors 2B are two magnetoresistive effect elements.
2 sets are provided, and the first set is the magnetoresistive effect element R1.
1 and R12, the second set is magnetoresistive effect elements R21 and R2
2 are provided, and the respective elements are arranged at intervals of λ1 / 2 and λ2 / 2. The relationship between λ1 and λ2 is λ2 = λ1
Since {n / (n ± 2)}, the distance between the magnetoresistive effect elements R21 and R22 in the second set is λ1 {n / (n ±
2)} / 2 are arranged at intervals.

Next, the operation of this embodiment will be described. The magnetic drum 1 rotates to rotate the magnetic recording medium 2A and the magnetic sensor 2B.
When the relative position to the magnetoresistive effect element changes, the characteristics of the magnetoresistive effect element with respect to the signal magnetic field Hs become as shown in FIG. One cycle of resistance change can be obtained. Therefore, the outputs of the magnetoresistive effect elements R11 and R21 become the waveforms sin1 and sin2 of FIG.
One rotation of the magnetic drum 1 results in 5 cycles and 6 cycles, respectively.
It becomes the output waveform of the cycle. In addition, the magnetoresistive element R
The outputs of 12 and R22 are 90 in electrical angle from the waveform of FIG.
The phase is delayed by degrees, that is, (λ1 / 2) and (λ2 / 2).

Now, comparing the output waveform sin1 of the magnetoresistive effect element R11 with the output waveform sin2 of R21, the phases of both waveforms are initially the same, but the directions of the arrows shown in FIGS. When rotated to, the phase of sin2 advances from the phase of sin1 and the phase difference becomes large corresponding to the rotation, and eventually it advances 360 ° in one rotation to become the same phase as the original phase. This is represented by a diagram showing the relationship between the position of the moving body and the phase difference of the magnetoresistive effect element output waveform shown in FIG. Therefore, the absolute position of one rotation can be detected by comparing the phase difference between sin1 and sin2. As described above, according to this embodiment, the absolute position of one rotation can be detected with a simple structure.

[Embodiment 3] Still another embodiment of the present invention will be described. FIG. 10 is a basic configuration diagram of a linear absolute position detecting device according to still another embodiment of the present invention. 1C is a magnetic recording medium, 2C is a magnetic sensor, and 4 is a support for the magnetic sensor 2C. As shown in FIG. 10, a linear absolute position detecting device according to still another embodiment of the first invention is a magnetic recording medium 1C.
Is two tracks T on which linearly continuous magnetic signals are recorded.
1, T2, a magnetic signal having a pitch λ1 is recorded on the first track T1, and a pitch λ is recorded on the second track T2.
2 magnetic signals are recorded. The magnetic sensor 2C is supported by a support 4 and is composed of magnetoresistive effect elements R11 and R21. When the magnetic recording medium 1C or the magnetic sensor 2C moves, the magnetic recording medium 1C
4 and FIG. 8 similarly to [Example 1] and [Example 2], the relative positions of the magnetic sensor 2C and the magnetic sensor 2C change, and the magnetic fields applied to the magnetoresistive effect elements R11 and R21 change.
The output of the waveform is obtained, the output waveforms sin1 and sin2 are compared, and the linear motion absolute position of the moving body can be detected from the relationship between the position of the moving body and the phase difference between the output waveforms.

[Embodiment 4] Still another embodiment of the present invention will be described. 11 is a development view of a rotary absolute position detecting device according to still another embodiment of the present invention, FIG. 12 is an output waveform diagram of a magnetoresistive effect element in the device of FIG. 11, and FIG. 13 is a moving body in the device of FIG. FIG. 6 is a diagram showing the relationship between the position and the phase difference of the magnetoresistive effect element output waveform.

As shown in FIG. 11, a rotary type absolute position detecting device according to still another embodiment of the first invention is shown in FIG.
The second embodiment has the same configuration as that of the second embodiment, except that the magnetic drum 1 is provided with three tracks. In FIG. 11, 1D is a magnetic recording medium and 2D is a magnetic sensor. The magnetic recording medium 1D is divided into three tracks, and the first and second tracks are [Example 1].
Although it has the same structure as that of [Embodiment 2], magnetic signals are recorded on the third track in a direction perpendicular to the magnetic signal recording directions of the first and second tracks as shown in the drawing. Further, the third magnetic signal recording is limited to half in the moving direction, and the other half is a non-recording portion.

The magnetoresistive effect elements of the magnetic sensor 2D disposed so as to face these tracks are the magnetoresistive effect elements R11 and R12 of the first set and the magnetoresistive effect elements R21 and R22 of the second set. Example 1] [Example 2]
The same structure and the same position as the magnetoresistive effect element of. In the present embodiment, a newly provided third magnetoresistive effect element R
Reference numeral 31 is arranged in a direction orthogonal to the first set of magnetoresistive effect elements R11, R12 and the second set of magnetoresistive effect elements R21, R22. These magnetoresistive effect elements R11 (R
The output waveform sin1 from 12) and the output waveform sin2 from R21 (R22) are the same as those in [Example 1] and [Example 2].

The output waveform of the third magnetoresistive effect element 31 is the first half (half rotation) as shown by E3 in FIG.
Is at the low level and the other half is at the high level. The relationship between the phase difference obtained from the outputs sin1 and sin2 and the moving position of the moving body is shown in FIG. Due to the combination of the value in FIG. 13 and the third output E3, since E3 is at a low level from positions a to b in FIG. 13, the absolute angle is 0.
It can be seen that the absolute angle is 180 to 360 degrees because E3 is at a high level from positions b to c in FIG. In this way, the absolute value of the angle of one rotation can be obtained.

[Embodiment 5] Still another embodiment of the present invention will be described. 14 is a development view of a rotary type absolute position detecting device according to still another embodiment of the present invention, FIG. 15 is an output waveform diagram of a magnetoresistive effect element in the device of FIG. 14, and FIG. 16 is a moving body in the device of FIG. FIG. 6 is a diagram showing the relationship between the position and the phase difference of the magnetoresistive effect element output waveform.

In FIG. 14, 1E is a magnetic recording medium and 2 is a magnetic recording medium.
E is a magnetic sensor. The magnetic recording medium 1E on the magnetic drum 1 is divided into two tracks T1 and T2, the number of magnetic signals NS recorded on the first track T1 is 10, and the number of magnetic signals NS on the second track T2 is 9. Configure as.
That is, the magnetic signal N of the first track of the magnetic recording medium
The number of S recorded is m (m; integer), and the number of magnetic signals NS of the second track is (m-1). On the other hand, the magnetic sensor 2E is composed of two sets of two magnetoresistive effect elements, and the arrangement thereof is such that the interval between the first set of magnetoresistive effect elements R11 and R12 is λ, as shown in FIG.
1/4, and the second set of magnetoresistive elements R21 and R22
Is set to λ2 / 4.

The relationship between λ1 and λ2 is λ2 = λ1 {m / (m
−1)}, the second group is arranged such that the magnetoresistive effect elements R21 and R22 are arranged at an interval of λ1 {m / (m−1)} / 4. Each magnetoresistive element R
The outputs of 11 and R21 are sin1 and si as shown in FIG.
It becomes n2. Therefore, the phase difference between sin1 and sin2 changes with respect to the position of the magnetic recording medium 1E as shown in FIG. 16, and changes linearly with a rising gradient from the starting point a to the ending point c. First set of magnetoresistive element R11
And the second set of magnetoresistive elements R21 or the first set of R1
The absolute position can be obtained by obtaining the phase difference between the output of 2 and the output of R22 of the second set.

[Embodiment 5] Still another embodiment of the present invention will be described. 17 is an output waveform diagram of a magnetoresistive effect element of a rotary type absolute position detecting device according to still another embodiment of the present invention, and FIG. 18 is a position of a moving body in the device of FIG. It is a diagram which shows the relationship with a corner. FIG. 19 is a diagram showing the relationship between the position of the moving body and the phase difference of the magnetoresistive effect element output waveform in the device of FIG. Since this embodiment has the same configuration as that of [Embodiment 1], the description thereof will be omitted.
This will be described with reference to FIGS. 18 and 19 and FIGS. 3, 4 and 5 of [Example 1].

This embodiment is based on [Embodiment 1] and [Embodiment
In 2], [Embodiment 3] and [Embodiment 4], it is possible to obtain a finer absolute position than the absolute position detecting device described above. As described with reference to FIG. 3, the first set of magnetoresistive effect elements R11 and R12 are arranged at an interval of λ1 / 4, and the second set of magnetoresistive effect elements R21 and R2.
2 is disposed at a distance of λ2 / 4.

Therefore, as shown in the waveform of FIG. 17, the outputs of the magnetoresistive effect elements R11 and R12 are sin.
1 and cos 1 with the phase angle advanced by 90 degrees from that. The outputs of the magnetoresistive elements R21 and R22 are sin2 and cos2 with a phase angle advanced by 90 degrees from that of sin2, respectively. First set of magnetoresistive elements R11 and R
An example of means for obtaining the phase angle θ1 from the respective outputs sin1 and cos1 of 12 and 12 is shown by the following equation. θ1 = tan (cos1 / sin1) or θ1 = cot (sin1 / cos1)

Similarly, the output s of the second set of magnetoresistive elements
An example of means for obtaining the phase angle θ2 from in2 and cos2 is shown by the following equation. θ2 = tan (cos2 / sin2) or θ2 = cot (sin2 / cos2) The phase angles θ1 and θ2 thus obtained are a within one cycle of each waveform as shown by θ1 and θ2 in FIG. Fine absolute positions are shown as a1, a2, a3, a4, a5, and a6.

Further, the phase difference (θ1-θ) shown in FIG.
The absolute position Δθ of the coarse resolution obtained from 2) is the positions a, a1, a2, a3, a4, a5 within the first one cycle.
Although it is a very small value at a6, the angle difference becomes close to 360 degrees at the final position c point, and the absolute position Δθ becomes the maximum value. This value and absolute position a, a1, a within one cycle
By adding 2, a3, a4, a5, and a6, continuous absolute positions with fine resolution can be obtained. According to this embodiment, an absolute position with high resolution can be detected.

[Embodiment 6] Next, an embodiment of the second invention will be described. 20 is a block diagram of a motor control device according to still another embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same parts, and thus the description thereof will be omitted. A motor control device according to an embodiment of the second invention is a motor control device equipped with a control motor for driving equipment and a position detector for detecting the position of the motor. It is configured using the absolute position detection device according to the invention.

In FIG. 20, M is a control motor having a rotary shaft J. The rotation axis J and the rotation axis of the magnetic drum 1 are common. Then, the control motor M and the magnetic drum 1 rotate around the axis J. The magnetic drum 1 is provided with two tracks T1 and T2, and the magnetic sensor 2 is fixed by a support 4 so as to face them. The magnetic sensor 2 has a magnetoresistive effect element R.
11 and R21 are mounted.

Next, the operation of this embodiment will be described. When the control motor M rotates by a certain angle according to the control signal, the magnetic drum 1 rotates by the same angle. From the two tracks T1 and T2 on the rotating magnetic drum 1, magnetic signals corresponding to the rotation angle are transmitted to the magnetoresistive effect elements R11 and R21 on the magnetic sensor 2. An electric signal is output from the magnetoresistive effect elements R11 and R21 in response to this transmission signal, and the absolute rotation position of the magnetic drum 1, that is, the control motor M can be detected with high resolution from the electric signal, as in [Example 1]. Motor control is possible.

Next, another embodiment of the second invention will be described. FIG. 21 is a control block diagram of a motor controller according to still another embodiment of the present invention. 21, M is a control motor, S is an absolute position detecting device, and P. C is a position controller, S. C is a speed control unit.

In the motor controller according to another embodiment of the second invention shown in FIG. 21, the control motor M is connected to the absolute position detector S via the motor shaft, and the position controller P.P. C
And speed control unit S. It is electrically connected to the speed control unit S.C. The output of C is input as the control signal of the control motor M. Further, the output e of the absolute position detecting device S is the position control unit P. C and speed control unit S. It is configured to be input to C.

Next, the operation of this embodiment will be described with reference to the control block diagram. Position control unit P.P. A position command is externally given to C, and it is compared with the output e of the absolute position detection device S, and an output signal corresponding to the deviation value is output to the speed control unit S. It is given to C as an input signal. Speed control unit S. At C, the input signal value is compared with the output e of the absolute position detecting device S, and a control output value corresponding to the difference is given to the control motor M as a current command or a voltage command to drive the motor. Since the system operates as described above, the control motor M can be accurately controlled in accordance with its absolute position.

[0046]

As described in detail above, according to the present invention, firstly, it is possible to provide an absolute position detecting device having a simplified structure, a small size, and high resolution. Secondly, it is possible to provide a high precision motor control device using the high resolution absolute position detection device.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of a rotary absolute position detection device according to an embodiment of the present invention.

FIG. 2 is a signal magnetic field characteristic diagram of a magnetoresistive effect element in the device of FIG.

FIG. 3 is a development view of a rotary absolute position detection device according to an embodiment of the present invention.

4 is an output waveform diagram of a magnetoresistive effect element in the apparatus of FIG.

5 is a diagram showing the relationship between the position of the moving body and the phase difference of the magnetoresistive effect element output in the apparatus of FIG.

FIG. 6 is a development view of a rotary absolute position detection device according to another embodiment of the present invention.

7 is a signal magnetic field characteristic diagram of a magnetoresistive effect element in the apparatus of FIG.

8 is an output waveform diagram of the magnetoresistive effect element in the apparatus of FIG.

9 is a diagram showing the relationship between the position of the moving body and the phase difference of the magnetoresistive effect element output in the apparatus of FIG.

FIG. 10 is a basic configuration diagram of a linear absolute position detection device according to still another embodiment of the present invention.

FIG. 11 is a development view of a rotary absolute position detection device according to still another embodiment of the present invention.

12 is an output waveform diagram of a magnetoresistive effect element in the device of FIG.

13 is a diagram showing the relationship between the position of the moving body and the phase difference of the magnetoresistive effect element output in the apparatus of FIG.

FIG. 14 is a development view of a rotary absolute position detection device according to still another embodiment of the present invention.

15 is an output waveform diagram of the magnetoresistive effect element in the device of FIG.

16 is a diagram showing the relationship between the position of the moving body and the phase difference of the magnetoresistive effect element output in the device of FIG.

FIG. 17 is an output waveform diagram of a magnetoresistive effect element according to still another embodiment of the present invention.

18 is a diagram showing the relationship between the position of the moving body and the phase angle of the magnetoresistive effect element output in the device of FIG.

19 is a diagram showing the relationship between the position of the moving body and the phase difference of the magnetoresistive effect element output according to the embodiment of FIG.

FIG. 20 is a block diagram of a motor controller according to still another embodiment of the present invention.

FIG. 21 is a control block diagram of a motor controller according to still another embodiment of the present invention.

[Explanation of symbols]

 1A, 1B, 1C, 1D, 1E Magnetic recording medium 2A, 2B, 2C, 2D, 2E Magnetic sensor R11, R12 First set of magnetic effect resistance element R21, R22 Second set of magnetic effect resistance element R31 Third set Magnetic effect resistance element T1 First track T2 Second track T3 Third track Hb Bias magnetic field M Control motor S Absolute position detector P. C position control unit S.I. C speed controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ichiro Hashimoto 1st 1st Higashitagacho, Hitachi City, Ibaraki Prefecture Hitachi Ltd. Taga Factory

Claims (16)

[Claims] 1. A moving body provided with a magnetic recording medium, which is mounted on a moving body or a fixed body, for recording a magnetic signal NS, and a magnetic sensor comprising a magnetoresistive element mounted on the fixed body or the moving body. In a position detecting device for detecting a position, the magnetic recording medium is divided into two tracks, n magnetic signals (n; even number) are recorded in a first track and (n ± 2) are recorded in a second track. Each of the magnetic signals is recorded, and the magnetic sensor is composed of two sets of magnetoresistive effect element groups,
The first set of magnetoresistive element groups is on the first track,
The second set of magnetoresistive effect element groups are arranged so as to face the second track, respectively, and the first electrical angle θ1 obtained from the output of the first set of magnetoresistive element groups and the second set Second electrical angle θ obtained from the output of the magnetoresistive element group of
An absolute position detecting device, characterized in that an absolute position of the moving body is obtained from a phase difference from 2. 2. A magnetoresistive effect element group of each set is composed of a plurality of magnetoresistive effect element groups, and each magnetoresistive effect element group is composed of two groups that generate a sin wave and a cos wave. The absolute position detecting device according to claim 1. 3. The magnetoresistive effect element group of each set is composed of a plurality of magnetoresistive effect element groups, and the magnetoresistive element group of the first set has a recording pitch of the magnetic signal NS as λ,
a plurality of them are arranged at intervals of λ / 4, and a plurality of the second group of magnetoresistive element groups are arranged at intervals of [n / (n ± 2)] × (λ / 4). The absolute position detection device according to claim 1. 4. A magnetoresistive effect element group of each set is provided with a bias magnetic field by a bias means, and is composed of a plurality of magnetoresistive effect element groups. Let λ be the pitch of λ / 2
2. A plurality of magnetoresistive element groups of the second set are arranged at intervals of [n / (n ± 2)] × (λ / 2). 1. The absolute position detection device according to 1. 5. A phase difference between a first electrical angle θ1 obtained from the output of the first set of magnetoresistive element groups and a second electrical angle θ2 obtained from the output of the second set of magnetoresistive element groups. The position is obtained, the fine position within one cycle is obtained from the sin wave and the cos wave obtained from the output of the magnetoresistive element group of either the first set or the second set, and the coarse position and the fine position are combined. The absolute position detecting device according to claim 2, wherein the absolute position with high resolution is obtained. 6. A moving body provided with a magnetic recording medium, which is mounted on a moving body or a fixed body, for recording a magnetic signal NS, and a magnetic sensor comprising a magnetoresistive effect element, which is mounted on the fixed body or the moving body. In a position detecting device for detecting a position, the magnetic recording medium is divided into three tracks, n magnetic signals (n; an even number) are recorded in a first track, and (n ± 2) are recorded in a second track. Magnetic signals in a direction orthogonal to the magnetic recording directions of the first track and the second track are recorded on the third track, and the magnetic sensor includes three sets of magnetoresistive effect elements. In groups,
The first set of magnetoresistive element groups is on the first track,
The second set of magnetoresistive element groups is on the second track,
The magnetoresistive effect element group of the third set is arranged so as to face the third track, respectively, and the first electrical angle θ1 and the magnetic force of the second set obtained from the output of the magnetoresistive element group of the first set are set. The absolute position of the moving body is obtained from the phase difference from the second electric angle θ2 obtained from the output of the resistance element group and the third electric signal obtained from the output of the third set of magnetoresistive element groups. Absolute position detector. 7. A magnetic recording medium, which is mounted on a moving body or a fixed body, for recording a magnetic signal NS, and a magnetic sensor comprising a magnetoresistive element mounted on the fixed body or the moving body. In a position detecting device for detecting a position, the magnetic recording medium is divided into two tracks, m magnetic signals (m; integer) are provided in a first track, and (m ± 1) magnetic signals are provided in a second track. Respectively recording the magnetic signal of, the magnetic sensor is composed of two sets of magnetoresistive effect element group,
The first set of magnetoresistive element groups is on the first track,
The second set of magnetoresistive effect element groups are arranged so as to face the second track, respectively, and the first electrical angle θ1 and the second set of magnetic fields obtained from the output of the first set of magnetoresistive element groups are arranged. An absolute position detecting device characterized in that an absolute position of the moving body is obtained from a phase difference from a second electric angle θ2 obtained from an output of the resistance element group. 8. The magnetoresistive effect element group of each set is composed of a plurality of magnetoresistive effect element groups, and each of the magnetoresistive effect element groups is composed of two groups for generating a sin wave and a cos wave. The absolute position detection device according to claim 7. 9. A magnetoresistive effect element group of each set is composed of a plurality of magnetoresistive effect element groups, and the magnetoresistive element group of the first set has a λ / 4 ratio, where λ is the pitch of the magnetic signal NS. A plurality of magnetoresistive elements are arranged at intervals and the second group of magnetoresistive elements is
8. The absolute position detecting device according to claim 7, wherein a plurality of (m ± 1)] × (λ / 4) are arranged. 10. The magnetoresistive effect element group of each set is provided with a bias magnetic field by a bias means and is composed of a plurality of magnetoresistive effect element groups, and the first set of magnetoresistive element groups has a pitch of a magnetic signal NS. Where λ is λ, a plurality of magnetoresistive element groups are arranged at an interval of λ / 2.
8. The absolute position detecting device according to claim 7, wherein a plurality of them are arranged at an interval of (m ± 1)] × (λ / 2). 11. A phase difference between a first electrical angle θ1 obtained from the output of the first set of magnetoresistive element groups and a second electrical angle θ2 obtained from the output of the second set of magnetoresistive element groups. The position is obtained, the fine position within one cycle is obtained from the sin wave and the cos wave obtained from the output of the magnetoresistive element group of either the first set or the second set, and the coarse position and the fine position are combined. 9. The absolute position detecting device according to claim 8, wherein the absolute position with high resolution is obtained. 12. A moving body provided with a magnetic recording medium, which is attached to a moving body or a fixed body, for recording a magnetic signal NS, and a magnetic sensor made of a magnetoresistive effect element, which is attached to the fixed body or the moving body. In a position detecting device for detecting a position, the magnetic recording medium is divided into three tracks, and the first track contains m (m; integer) magnetic signals and the second track contains (m ± 1) magnetic signals. Magnetic signals of (m ± 2) are recorded on the third track, and the magnetic sensor is composed of three groups of magnetoresistive effect elements,
The first set of magnetoresistive element groups is on the first track,
The second set of magnetoresistive element groups is on the second track,
The magnetoresistive effect element group of the third set is arranged so as to face the third track, respectively, and the first electrical angle θ1 and the magnetic force of the second set obtained from the output of the magnetoresistive element group of the first set are set. The absolute position of the moving body is obtained from the phase difference from the second electric angle θ2 obtained from the output of the resistance element group and the third electric angle θ3 obtained from the output of the third set of magnetoresistive element groups. Absolute position detection device. 13. A position of the moving body provided with a magnetic recording medium, which is attached to the moving body or the fixed body, for recording a magnetic signal NS, and a magnetic sensor comprising a magnetoresistive effect element attached to the fixed body or the moving body. In the position detecting device for detecting the magnetic field, the magnetic recording medium is divided into three tracks, and the first track contains m (m; integer) magnetic signals and the second track contains (m ± 1) magnetic signals. Magnetic signals are respectively recorded, and magnetic signals are recorded on the third track in a direction orthogonal to the magnetic recording directions of the first and second tracks, and the magnetic sensor is composed of three sets of magnetoresistive effect element groups. Configure and
The first set of magnetoresistive element groups is on the first track,
The second set of magnetoresistive element groups is on the second track,
The magnetoresistive effect element group of the third set is arranged so as to face the third track, respectively, and the first electrical angle θ1 and the magnetic force of the second set obtained from the output of the magnetoresistive element group of the first set are set. The absolute position of the moving body is obtained from the phase difference from the second electric angle θ2 obtained from the output of the resistance element group and the third electric signal obtained from the output of the third set of magnetoresistive element groups. Absolute position detector. 14. A motor control device comprising a control motor for driving equipment and a position detector for detecting the position of the motor, wherein the absolute position detection device according to claim 1 is used for the position detector. A characteristic motor control device. 15. A device comprising a control motor for driving a device and a position detector for detecting a position, wherein the position detection is performed by comparing an output signal of the position detection device with a position setting command. A motor position control device, wherein the absolute position detection device according to claim 1 is used in a container. 16. A device comprising a control motor for driving a device and a position detector for detecting the position of the motor, wherein speed control is performed by comparing an output signal of the position detector with a speed setting command. A motor speed control device, wherein the absolute position detection device according to claim 1 is used as a position detector.