JP2012098166A - Vernier type position detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vernier type position detecting device capable of simplifying the structure of the device and detecting a position by a simple processing.SOLUTION: An inner magnetic pole pattern 6b having four magnetic pole pairs is provided nearer the inside of a rotor plate 3, and an outer magnetic pole pattern 7b having three magnetic pole pairs is provided nearer the outside of the rotor plate 3. A first sensor part 6a is provided at a position facing the inner magnetic pole pattern 6b, and a second sensor part 7a is provided at a position facing the outer magnetic pole pattern 7b. The second sensor part 7a is disposed by deflecting it by a prescribed amount in a rotating direction of the rotor plate 3 in relation to the outer magnetic pole pattern 7b. Consequently, a signal combination of the first sensor part 6a and the second sensor part 7a, and a detecting angle of the rotor plate 3 have a univocal value. Therefore, a rotation angle of the rotor plate 3 can be detected by just confirming the signal combination of the first sensor part 6a and the second sensor part 7a.

Description

  The present invention relates to a vernier type position detection device that detects the position of an object to be measured by a signal combination of detection signals output from two detection means.

  Conventionally, a vernier type position detection device 81 (for example, Patent Document 1) as shown in FIG. 8 is known as a position detection device that accurately detects the position of an object to be measured. In the vernier position detecting device 81, a disk-shaped rotating plate 82 is formed to be rotatable around a shaft 83. A pair of magnetic pole patterns 84 and 85 in which a plurality of N-pole and S-pole magnetic pole pairs are arranged around the axis 83 are formed on the rotary plate 82 inside and outside in the radial direction of the rotary plate 82. In the case of this example, four sets of magnetic pole pairs are formed on the inner magnetic pole pattern 84 positioned on the radially inner side, and three sets of magnetic pole pairs are formed on the outer magnetic pole pattern 85 positioned on the radially outer side.

  As shown in FIGS. 9 and 10, a pair of inner magnetic sensor portions 86 and 87 for detecting a magnetic field radiated from the inner magnetic pole pattern 84 is provided at a position facing the inner magnetic pole pattern 84. The inner magnetic sensor portions 86 and 87 are arranged side by side in the magnetic pole arrangement direction on the side of the inner magnetic pole pattern 84. Specifically, one inner magnetic sensor unit 86 is arranged in the middle of the magnetic pole arrangement direction at the N pole at the left end of the inner magnetic pole pattern 84 in the drawing, and the other inner magnetic sensor unit 87 is adjacent to the N pole. It is located at the boundary with the S pole. The inner magnetic sensor unit 86 outputs the magnetic field detected from the inner magnetic pole pattern 84 to the controller 88 with a detection signal Sa1 according to the sin wave shown in FIG. Further, the inner magnetic sensor unit 87 outputs the magnetic field detected from the inner magnetic pole pattern 84 to the controller 88 with a detection signal Sa2 conforming to the cos wave shown in FIG.

  A pair of outer magnetic sensor units 89 and 90 for detecting a magnetic field radiated from the outer magnetic pole pattern 85 are provided at positions facing the outer magnetic pole pattern 85. The outer magnetic sensor units 89 and 90 are arranged under the same position conditions as the inner magnetic sensor units 86 and 87, and the detection signal Sb1 according to the sin wave shown in FIG. The detection signal Sb2 conforming to the cos wave shown in FIG. 11B is output from the outer magnetic sensor unit 90 to the controller 88.

  The controller 88 calculates arctan θ based on sin θ and cos θ acquired from the inner magnetic sensor units 86 and 87, and calculates a rotational output according to the inner magnetic pole pattern 84 based on sin θ and cos θ and the determined arctan θ. The controller 88 calculates arctan θ based on sin θ and cos θ acquired from the outer magnetic sensor units 89 and 90, and calculates a rotation output according to the outer magnetic pole pattern 85 based on sin θ and cos θ and arctan θ determined from these. . The reason why arctan θ is calculated in the angle detection is to calculate arctan θ and classify these two values because there are two angles for one combination of sin θ and cos θ.

  The controller 88 calculates the rotation angle (rotation position) of the rotating plate 82 based on the signal combination of the rotation output obtained from the inner magnetic sensor units 86 and 87 and the rotation output obtained from the outer magnetic sensor units 89 and 90. For example, the controller 88 detects the rotation angle of the rotating plate 82 with a resolution of “72”.

JP 2008-267867 A

  However, the angle calculation described in the background art requires a total of four sensor components inside and outside, such as arranging two sensor units 86 and 87 inside and arranging two sensor units 89 and 90 outside. It was. For this reason, there was a need to reduce the number of sensor parts. The angle calculation of the background art is a calculation using arctan θ from sin θ and cos θ obtained from the sensor units 86 and 87 (89, 90) and using these three parameters. For this reason, there also existed a problem that arithmetic processing was complicated and time was required.

  An object of the present invention is to provide a vernier type position detection apparatus that can simplify the structure of the apparatus and can detect the position by simple processing.

  In order to solve the above problems, in the present invention, a position detection unit comprising a set of a detection unit arranged on one side and a detection unit arranged on the other side is provided between the measurement object and its support. A plurality of vernier position detection devices that detect the position of the object to be measured by a signal combination of a first detection signal output from the first position detection unit and a second detection signal output from the second position detection unit. If the detection signals output from the first position detection unit and the second position detection unit are unit detection values when the unit of resolution is position detection, each unit detection value takes an AC wave. The gist is that two detection values are set within one wavelength of the detection signal.

  According to this configuration, the signal combination of the first detection signal output from the first position detection unit and the second detection signal output from the second position detection unit detects the position of the object to be measured in units of resolution. Each position is determined uniquely. Therefore, since the position of the object to be measured can be detected by the two position detectors, the structure of the apparatus can be simplified, and the position can be detected by a simpler process. .

  In the present invention, when the signal combination and the angle are not uniquely determined, one of the first position detection unit and the second position detection unit adjusts the positional relationship between the detection unit and the detected unit. The gist.

  According to this configuration, even when the signal combination and the angle are not uniquely determined, by adjusting the position of the component, the signal combination and the angle are set to values that satisfy the unambiguous relationship. It becomes possible to set.

In the present invention, the first position detection unit and the second position detection unit are (a) the number of divisions of the first position detection unit, where the number of divisions of one wavelength of the detection signal is the division number. And the number of divisions of the second position detector is an even number, (b) the number of divisions is divisible by a numerical value of 4 or more, and (c) the resolution of position detection is the first position detector. And (d) the detection signal of the AC wave is such that the unit detection value takes two identical values within one wavelength. It is summarized that the above conditions (a) to (d) are set.
According to this configuration, a desired signal combination can be obtained more reliably.

  In the present invention, when one of the first position detection unit and the second position detection unit outputs a sine wave as a detection signal and the other outputs a cosine wave as a detection signal, the first position detection unit and the second position detection unit Assuming that the position taken by the second position detection unit is a reference position, one of the first position detection unit and the second position detection unit is shifted in the moving direction with respect to the other. The gist is that the unit detection values are set to take two identical values by arranging them.

  According to this configuration, for example, the detected portion can be used as it is without changing the position, shape, or the like.

  According to the present invention, the structure of the apparatus can be simplified, and the position can be detected by simple processing.

The perspective view of the vernier type position detection apparatus of one Embodiment. The top view of a rotating plate. The block diagram of the magnetic pole pattern formed in the rotating plate. The wave form diagram of the detection signal output from a position detection sensor. An allocation table showing the relationship between signal combinations and angles. The block diagram of a vernier type position detection apparatus. The illustration figure explaining the thought of the invention of this application. The block diagram of the conventional vernier type position detection apparatus. The block diagram of the magnetic pole pattern formed in the rotating plate. The block diagram of a vernier type position detection apparatus. (A), (b) is a wave form diagram of a detection signal which each sensor part inside and outside outputs.

Hereinafter, an embodiment of a vernier type position detection apparatus embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, a substantially disc-shaped rotating plate 3 is pivotally supported by the case 2 of the vernier type position detecting device 1 so as to be rotatable around a central axis 4. The rotating plate 3 rotates around the axis 4 in synchronization with the movement of the article whose position is to be detected. Note that the case 2 corresponds to a support, and the rotating plate 3 corresponds to an object to be measured.

  A plurality (two in this example) of position detection sensors 5 for detecting the rotation angle (rotation position) of the rotation plate 3 are provided between the case 2 and the rotation plate 3. The two position detection sensors 5 are arranged side by side in the radial direction of the rotating plate 3 and, for example, a magnetic sensor is used. In the case of this example, the radially inner side in FIG. 1 is the first position detection sensor 6, and the radially outer side in FIG. 1 is the second position detection sensor 7. The position detection sensors 5 to 7 constitute a position detection unit, the first position detection sensor 6 corresponds to the first position detection unit, and the second position detection sensor 7 corresponds to the second position detection unit.

  A first sensor portion 6 a is provided as a sensing component of the first position detection sensor 6 at a position closer to the inside in the radial direction on the inner wall surface 8 of the case 2. Further, a second sensor portion 7 a is provided as a sensing component of the second position detection sensor 7 at a position closer to the outer side in the radial direction on the inner wall surface 8 of the case 2. As the first sensor unit 6a and the second sensor unit 7a, for example, an MRE (magnetoresistive element) or a Hall element is used. The 1st sensor part 6a and the 2nd sensor part 7a output the detection signal according to the detected magnetic field. In addition, the 1st sensor part 6a and the 2nd sensor part 7a comprise a detection part.

  As shown in FIG. 2, an inner magnetic pole pattern 6 b in which a plurality of N-pole and S-pole pairs are arranged in an annular shape around the shaft 4 is formed on the rotary plate 3 at a position closer to the inner side in the radial direction. The inner magnetic pole pattern 6b is composed of four magnetic pole pairs. Further, an outer magnetic pole pattern 7b in which a plurality of N-pole and S-pole pairs are arranged in an annular shape around the shaft 4 is formed on the rotary plate 3 at a position closer to the outside in the radial direction. The outer magnetic pole pattern 7b is composed of three magnetic pole pairs. The inner magnetic pole pattern 6b and the outer magnetic pole pattern 7b constitute a detected part.

  The first position detection sensor 6 and the second position detection sensor 7 of this example are set so as to satisfy the following four conditions. In the case of this example, in each output of the AC wave of the first position detection sensor 6 and the second position detection sensor 7, the number when equally dividing one wavelength (one magnetic pole pair) is referred to as a division number. I will decide.

[conditions]
When the division number of the first position detection sensor 6 is n1, and the division number of the second position detection sensor 7 is n2, both the division numbers n1 and n2 are set to an even number.
-The division numbers n1 and n2 are both divisible by 4 or more.
-The resolution of position detection must be set by the least common multiple of the division numbers n1 and n2.
The sensor outputs respectively output from the first position detection sensor 6 and the second position detection sensor 7 in units of resolution have two same angles within one magnetic pole pair (within one wavelength of the sensor output).

  A structure taken by the first position detection sensor 6 and the second position detection sensor 7 by satisfying these conditions will be described below. In the case of this example, since the division number n1 of the first position detection sensor 6 is “18” and the division number n2 of the second position detection sensor 7 is “24”, the resolution of the vernier type position detection apparatus 1 of this example is Is “72” which is the least common multiple of “18” and “24”. Therefore, the vernier type position detection device 1 of the present example can detect the rotation angle of the rotating plate 3 at intervals of 5 degrees.

  As shown in FIG. 3, the first sensor unit 6a is arranged in the middle of the magnetic pole arrangement direction at the N pole located at the left end of the inner magnetic pole pattern 6b. The first sensor unit 6a outputs a first detection signal Sa in which the relationship between the detected magnetic field and the sensor output is a sine wave (sine wave) as shown in FIG. The first detection signal Sa has a waveform having one wavelength when the inner magnetic pole pattern 6b moves by one magnetic pole pair with respect to the first sensor unit 6a.

  As shown in FIG. 3, the second sensor portion 7a is disposed at a position shifted by a predetermined amount in the magnetic pole arrangement direction from the middle of the magnetic pole arrangement direction at the N pole located at the left end of the outer magnetic pole pattern 7b. That is, if the first position detection sensor 6 outputs a sine wave as a signal waveform corresponding to the angle, and the second position detection sensor 7 outputs a cosine wave as a signal waveform corresponding to the angle, the first position detection sensor 6 is output. Assuming that the position taken by the second position detection sensor 7 is a reference position, the second sensor portion 7a of this example is arranged with a predetermined amount shifted from the reference position in the magnetic pole arrangement direction (rotation direction of the rotating plate 3). . Therefore, the second sensor unit 7a outputs the second detection signal Sb offset in the horizontal axis direction as shown in FIG. The second detection signal Sb has a waveform having one wavelength when the outer magnetic pole pattern 7b moves by one magnetic pole with respect to the second sensor unit 7a.

  In the first position detection sensor 6 and the second position detection sensor 7 of this example, if the detection values output in units of angle detection resolution are unit detection values D1 and D2, respectively, these unit detection values D1 and D2 are 1 Each of the magnetic pole pairs is set to have two angles (an angle in resolution unit). That is, when the first position detection sensor 6 takes a predetermined unit detection value D1, or when the second position detection sensor 7 takes a predetermined unit detection value D2, each has two angles (the same value). Is set. For this reason, the waveform connecting the plot points of the unit detection value D1 and the waveform connecting the plot points of the unit detection value D2 appear to have a substantially trapezoidal shape.

  When the first position detection sensor 6 and the second position detection sensor 7 are arranged under the above-described conditions, the first detection signal Sa of the first position detection sensor 6 and the second detection signal Sb of the second position detection sensor 7 are used. And the signal combination have the relationship shown in the allocation table 9 of FIG. That is, the combination of the output value of the first detection signal Sa and the output value of the second detection signal Sb takes different values for each angle detection resolution. Therefore, the rotation angle of the rotating plate 3 is uniquely determined from the signal combination of the first detection signal Sa and the second detection signal Sb.

  As shown in FIG. 6, the vernier position detection device 1 is provided with a controller 10 that calculates the rotation angle of the rotating plate 3 by a vernier method. A first position detection sensor 6 and a second position detection sensor 7 are connected to the controller 10. The controller 10 determines the rotation angle of the rotating plate 3 based on the signal combination of the first detection signal Sa output from the first position detection sensor 6 and the second detection signal Sb output from the second position detection sensor 7. And the calculated rotation angle is output to another ECU.

Next, operation | movement of the vernier type position detection apparatus 1 of this example is demonstrated using FIGS.
The position state shown in FIG. 3 is defined as an initial position for starting rotation (that is, a rotation angle “0”). At this time, as shown in the allocation table 9 in FIG. 5, the output value of the first position detection sensor 6 takes “0.000”, and the output value of the second position detection sensor 7 takes “−0.131”. Therefore, the controller 10 detects the rotation angle of the rotating plate 3 as 0 degree.

  It is assumed that the rotating plate 3 is rotated counterclockwise in FIG. 2, for example, from the initial position. At this time, as shown in FIG. 5, when the rotating plate 3 rotates by 5 degrees, the output value of the first position detection sensor 6 takes “0.342”, and the output value of the second position detection sensor 7 becomes “0.131”. Take. Therefore, the controller 10 detects the rotation angle of the rotating plate 3 as 5 degrees.

  When the rotating plate 3 is further rotated in the counterclockwise direction, the output of the first detection signal Sa and the second detection signal Sb is switched according to the rotation. At this time, the controller 10 sequentially calculates the signal combination of the first detection signal Sa and the second detection signal Sb, sequentially calculates the rotation angle of the rotating plate 3 based on this signal combination, and sends the calculated rotation angle to other ECUs. Output.

  By the way, as can be seen from the allocation table 9 in FIG. 5, there is only one signal combination of the first detection signal Sa and the second detection signal Sb at each angle of resolution. That is, the signal combination of the first detection signal Sa and the second detection signal Sb and the resolution angle are uniquely determined. Therefore, it can be seen that the rotational position of the rotating plate 3 can be detected simply by looking at the combination of the output from the first position detection sensor 6 and the output from the second position detection sensor 7.

  By the way, depending on the case, the signal combination of the first detection signal Sa and the second detection signal Sb and the desired angle may not be uniquely determined. At this time, for example, one of the two magnetic pole patterns 6b and 7b is shifted by a predetermined amount in the rotation direction with respect to the other. In this way, since the signal combination and the angle have a unique relationship, the angle can be detected directly from the output of the position detection sensors 6 and 7 without any problem.

  As described above, in this example, the first position detection sensor 6 and the second position detection sensor 7 are arranged so as to satisfy the above-described conditions. Therefore, as shown in FIG. 7, the first detection signal Sa and the second detection signal Sb have two waveforms having the same angle when taking the unit detection values D1 and D2 in one magnetic pole pair. That is, by disposing the second sensor unit 7a by a predetermined amount from the reference position with respect to the outer magnetic pole pattern 7b, both the first detection signal Sa and the second detection signal Sb have the same angle within one magnetic pole pair. Make it a waveform.

  Therefore, as shown in FIG. 5, the combination of the output of the first position detection sensor 6 and the output of the second position detection sensor 7 takes a value that is uniquely determined by each of the angle detection resolutions. Therefore, the angle of the rotating plate 3 can be detected simply by looking at the signal values of the first position detection sensor 6 and the second position detection sensor 7. Therefore, it is possible to detect the angle with a small number of sensors, and it is also possible to detect the angular position by simple calculation.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) Since the first position detection sensor 6 and the second position detection sensor 7 are arranged so that the signal combination takes the allocation table 9 in FIG. 5, the rotation position of the rotating plate 3 is set to the first position detection sensor 6 and It can be detected by two sensors of the second position detection sensor 7. For this reason, since the number of sensors to be used is small, the configuration of the vernier type position detecting device 1 can be simplified. In addition, since the angle can be determined by simply confirming the signal combination of the first detection signal Sa and the second detection signal Sb, the rotation angle of the rotating plate 3 can be detected by a simple process.

  (2) When the signal combination and the angle are not uniquely determined, one of the pair of magnetic pole patterns 6b and 6b is shifted by a predetermined amount and adjusted. Therefore, even if the signal combination and the angle do not satisfy the unambiguous relationship, this can be dealt with.

  (3) The positions of the first position detection sensor 6 and the second position detection sensor 7 are set to the four conditions described in the embodiment. Therefore, the signal combination of the first detection signal Sa and the second detection signal Sb can be more reliably set to a combination that uniquely has one angle.

  (4) By arranging the second sensor unit 7a to be shifted from the reference position by a predetermined angle in the rotation direction with respect to the outer magnetic pole pattern 7b, the signal combination of the first detection signal Sa and the second detection signal Sb has a unique angle. It was set to be a combination to take. Therefore, since it is not necessary to change the first position detection sensor 6 (first sensor unit 6a, inner magnetic pole pattern 6b) and outer magnetic pole pattern 7b, conventional ones can be used as they are.

Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.
-The division | segmentation number of the 1st position detection sensor 6 and the 2nd position detection sensor 7 can be changed suitably.
For example, the rotating plate 3 may be on the fixed side, and the sensor units 6a and 7a may be on the rotating side.

-The position detection sensor 5 is not limited to a magnetic sensor, For example, you may employ | adopt other types, such as an optical sensor.
The position detection unit is not limited to the contactless position detection sensor 5, and may be a contact type such as a switch.

The rotating plate 3 is not limited to a circular plate, and other shapes may be used.
The position detection sensor 5 is not limited to be arranged in the radial direction of the rotating plate 3, and may be arranged in the thickness direction of the rotating plate 3, for example.

  When the signal combination of the first detection signal Sa and the second detection signal Sb is set so as to have a unique angle, the position of the second sensor unit 7a is not limited to being shifted with respect to the outer magnetic pole pattern 7b. . For example, the position of the second sensor portion 7a may be the same as the conventional one, and the outer magnetic pole pattern 7b may be shifted in the rotational direction.

  The first position detection sensor 6 and the second position detection sensor 7 are not limited to satisfying the four conditions described in the embodiment. For example, it may have a condition that the sensor output has two different angles within one magnetic pole pair.

A numerical value that is not divisible by 2 may be adopted as the number of pattern divisions of the position detection sensor 5.
Adjustment when the signal combination of the first detection signal Sa and the second detection signal Sb and the desired angle are not uniquely determined is not limited to shifting the magnetic pole pattern side, for example, shifting the sensor unit side You may arrange.

The number of position detection sensors 5 is not limited to two and may be three or more.
The vernier type position detection device 1 is not limited to the rotation type that detects the rotation angle, but may be a linear type that detects the object to be measured that moves linearly.

Next, technical ideas that can be grasped from the above-described embodiment and other examples will be described below together with their effects.
(A) In any one of claims 1 to 4, the vernier type position detecting device detects a rotation angle of the object to be measured that rotates. According to this configuration, the rotation angle of the rotating object to be measured can be accurately detected.

  (B) In any one of claims 1 to 4 and the technical idea (A), the position detection unit is a contactless type. According to this configuration, since the contact portion does not deteriorate due to component contact or the like, the durability of the apparatus can be ensured.

  DESCRIPTION OF SYMBOLS 1 ... Vernier type position detection apparatus, 2 ... Case as support body, 3 ... Rotating plate as to-be-measured object, 5 ... Position detection sensor which comprises position detection part, 6 ... Position detection part (1st position detection part) The first position detection sensor constituting 6a, the first sensor part constituting the detection part, 6b, the inner magnetic pole pattern constituting the detected part, 7 ... the second constituting the position detection part (second position detection part). Position detection sensor, 7a ... second sensor part constituting the detection part, 7b ... outer magnetic pole pattern constituting the detected part, Sa ... first detection signal constituting the detection signal, Sb ... second detection constituting the detection signal Signal, D1, D2... Unit detection value, n1, n2.

Claims (4)

A plurality of position detection units each including a set of a detection unit arranged on one side and a detection unit arranged on the other side are provided between the object to be measured and its support, and the first position detection unit outputs the first In a vernier type position detection device that detects the position of the object to be measured by a signal combination of one detection signal and a second detection signal output from the second position detection unit,
When the detection signals output from the first position detection unit and the second position detection unit in the unit of position detection resolution are unit detection values, each unit detection value is the detection signal that takes an AC wave. A vernier type position detecting device, which is set so as to take two identical values within one wavelength. When the signal combination and the angle are not uniquely determined, the positional relationship between the detection unit and the detected unit is adjusted in one of the first position detection unit and the second position detection unit. Item 4. A vernier type position detection device according to item 1. The first position detector and the second position detector are
(A) Assuming that the number of equally dividing one wavelength of the detection signal is the number of divisions, the number of divisions of the first position detection unit and the number of divisions of the second position detection unit are both even numbers. (B) The division number is divisible by a numerical value of 4 or more. (C) The position detection resolution is set by the least common multiple of the division number of the first position detection unit and the division number of the second position detection unit. (D) The above conditions (a) to (d) are set such that the detection signal of the AC wave is set so that the unit detection value takes two identical values within one wavelength. The vernier type position detection apparatus according to claim 1 or 2, wherein When one of the first position detection unit and the second position detection unit outputs a sine wave as a detection signal and the other outputs a cosine wave as a detection signal, the first position detection unit and the second position detection If the position taken by the part is the reference position,
In one of the first position detection unit and the second position detection unit, one of the detection unit and the detected unit is shifted in the moving direction with respect to the other, so that the unit detection value becomes two identical values. The vernier type position detecting device according to any one of claims 1 to 3, wherein the vernier type position detecting device is set so as to take.

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