JP2548726B2 - Rotation angle detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention is used by being attached to a servo motor or the like for detecting and feeding back a rotation angle or a phase angle of a rotating portion in a servo system of various electric machines and equipment. The present invention relates to a rotation angle detection device, and more particularly to a rotation angle detection device capable of detecting an absolute angle.

[Conventional technology and problems]

As the rotation angle detecting device as described above, there are inductive type detecting devices such as photoelectric absolute encoder, synchro, resolver, microthin, etc. High-level technology is required for manufacturing, such as complicated patterns, and it is expensive, but it is difficult to obtain the precision and resolution required by recent precision control technology with conventional induction-type rotation angle detection devices. In today's demand for smaller size and lighter weight, the mechanical structure including the winding is complicated,
There was the problem that the device was bulky and heavy.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a low-priced rotation angle detection device that is compact and lightweight, can achieve high accuracy, and can achieve high resolution. It is in.

[Means for solving problems]

In the rotation angle detection device of the present invention made to solve the above problems, the circumference is first divided into n equal parts (n is an integer of 3 or more).
Bit information targets Bi (i = 0, ..., n−) that carry bit information at the respective equally divided points Pi (i = 0, ..., n−1)
The decimal number n for detecting the bit information of the rotor provided with 1) and the bit information target Bi of the rotor, respectively.
-1 and a stator provided with m (m is an integer of 2 or more) bit information detection units Sj (j = 0, ..., m-1), which is equal to or larger than the number of digits of binary display of -1. The information of the bit information target Bi of the rotor is the rotation angle detecting device provided such that the n pieces of m-bit data detected by the stator information detecting unit Sj by the rotation of the rotor are all different from each other. In this case, n absolute angles corresponding to the n binary data taken at times are detected.

Further, the present invention comprises the above rotation angle detection device and a relative angle detection device for detecting the relative angle between the rotor and the stator with each absolute angle detected thereby as a reference point. The absolute angle of the rotor is detected with high resolution.

[Action]

In the rotation angle detecting device of the present invention having the above-described structure, each bit information target Bi passes through the predetermined absolute angle reference point (0 °) one after another while the rotor makes one rotation, but at each instant of time. For example, n pieces of n-bit binary data obtained by reading the bit information of the n pieces of target Bi in the same direction in the circumferential direction from the absolute angle reference point are all different from each other. One can correspond to one of n absolute angles obtained by dividing 360 ° including the angle reference point into n equal parts.

Therefore, the absolute angle of the rotor at each moment can be known by detecting the bit information of each bit information target Bi by the bit information detection unit provided in the stator and knowing the binary data formed by this. It is not necessary to provide n bit information detecting units, one for each bit information target Bi, and to provide m bits (m is an integer of 2 or more) that is equal to or larger than the number of digits in the binary notation of the decimal number n-1. Sufficient n binary data can be identified.

Further, according to the present invention, the absolute angle of the rotor is provided by providing the relative angle detection device for detecting the relative angle between the rotor and the stator with each absolute angle detected by the rotation angle detection device as a reference point. Can be detected with high resolution.

〔Example〕

Hereinafter, embodiments of the rotation angle detecting device of the present invention will be described with reference to the drawings.

The embodiment of the rotation angle detecting device of the present invention shown in FIG. 1 comprises an absolute angle detecting portion 1 and a relative angle detecting portion 2, and the absolute angle detecting portion 1 includes an absolute angle detecting device 3, a discriminating device 4, and an aligner 5. And an 8-bit output unit 6. The relative angle detection unit 2 is composed of a relative angle detection device 7, an R / D (resolver digital) converter 8, an origin signal generator 9, and a 10-bit output unit 10.

The absolute angle detecting device 3 is composed of a rotor 11 and a stator 12, and the rotor 11 is formed by stacking several sheets of electromagnetic steel sheets formed on each other. The outer periphery of the rotor 11 is divided into n equal parts (n = 256 in the illustrated embodiment). = 2 ⁸⁾ was the equally divided points Pi (i = 0, ......, n-
Bit information targets Bi (i = 0, ..., N-1) are provided in 1). Bit information target Bi is bit 1
Corresponds to a salient pole, and that corresponding to bit 0 consists of a non-salient pole or a semi-salient pole (shown by a broken line) that is sufficiently shorter than the salient pole of bit 1 (of course, bit 0 is a salient pole target, Bit 1 can also be a non-salient or semi-salient target).

Similarly, the stator 12 is also made of an electromagnetic steel plate, and the inner circumference thereof is provided with m (n = 256 in the illustrated embodiment, so m = 8 is sufficient) n or more digits in the binary display of n-1. The salient poles forming the bit information detection unit Sj (j = 0, ..., M-1) are provided.

Here, the configuration and operation of the absolute angle detection device 3 will be described in detail with reference to FIG. However, in FIG. 2, the rotor 11 is shown for simplification of illustration and description.
Let n = 12 be the number of equal divisions. In this case, m = 4 is sufficient for the number m of bit information detection units Sj. In FIG. 2, twelve bit information targets Bi (i = 0, ..., 1 of the rotor 11
1) is, for example, when each target Bi is located at the absolute angle reference point (0 °) as shown in the figure, the bit information of all the targets is clockwise or counterclockwise with the target Bi as the most significant bit or the least significant bit. The 12-bit binary data obtained by reading is shown in the following table.

Each of the four bit information detectors Sj (j = 0, ...
The primary windings connected in series to the oscillator 13 are wound around the salient poles of 3) so that the winding directions of the adjacent windings are reversed, and the secondary windings are provided for each salient pole. Separate output s ₀ , ……, s ₃
Each is independently wound to obtain. oscillation When the respective primary windings of the stator 12 are excited by the output of the predetermined frequency of the transformer 13, exciting outputs s ₀ , ..., S ₃ are generated in the respective secondary windings, but the salient poles of the stator 12 and the rotor 11, stator 12
The air gap in the magnetic path formed through the yoke of
Bit information target Bi is salient poles of the rotor 11 opposed to the salient poles of the stator 12, it depends whether it is a non-salient pole, since the clear difference in reluctance occurs energized this output s _0, ......, s _{By 3,} it can be extracted as binary information. That is, for example, when the rotor 11 is in the angular position shown in FIG. 2, the output is not responded to the excitation input as shown in FIG.
Waveforms like s ₀ , ..., s ₃ are obtained, and s ₂ is smaller than the other outputs, so 1101 is obtained as binary data representing this absoluteization. With the value data, 12 (maximum 16) absolute angles of the rotor 11 corresponding to 12-bit (maximum 16 bits) binary data can be identified.

In this way, the rotor 11 has 256 bit information targets Bi (i = 0, ..., 255), and the stator 12 has eight bit information detection units Sj (j = 0, ..., 8). The absolute angle detection device 3 of the embodiment shown in FIG. 1 has eight binary signals whose combinations are all different from each other for 256 absolute angles of the rotor 11.
Generates s ₀ , ..., s ₇ . These binary signals are discriminator 4
Eight discriminator 4 _0, ..., are input to the 4 _7, the bit is judged whether it is a 1 or 0 is input in parallel at the same time to the alignment unit 5 as an 8-bit binary data.
When the 8-bit binary data input from the discriminator 4 is treated as a binary number, the aligner 5 is not arranged in the order of the absolute angles of the rotor 11, so that the rotor 11 is stored using the comparison table stored in advance in the ROM. The binary numbers arranged in the order of the absolute angles of are output to the 8-bit output unit 6. The 8-bit output unit 6 transfers these maximum 8-bit binary numbers to the 18-bit output unit 14 as upper bits.

As described above, the absolute angle detection device 3 of the above embodiment can be used as a rotation angle detection device capable of detecting 256 absolute angles of the rotor 11. Of course, the number of divisions n of the rotor 11 is
The number is not limited to 256 and is arbitrary. The thickness of the rotor 11 and the stator 12 may be several millimeters. Further, the bit information target Bi of the rotor 11 and the bit information detection unit Sj of the stator 12 utilize the magnitude of the induced electromotive force due to the change in reluctance as in the above-described embodiment, and each target Bi is, for example, bit 1
Is formed by dyeing white and bit 0 is black,
It is also possible to form each bit information detection unit Sj by a reflection type photo sensor. Further, it is also possible to magnetize the peripheral portion of the rotor 11 according to each bit information and detect it by a hall element.

In the embodiment of FIG. 1, the relative angle detecting device 7 of the relative angle detecting portion 2 is also composed of a rotor 15 and a stator 16, and the rotor 15 is the bit information target Bi of the rotor 11 of the absolute angle detecting device 3 described above. The same n salient poles Ci (i = 0, ...
, N-1) are formed, and four salient poles Dj are formed on the stator 16.
The salient poles adjacent to (j = 0, ..., 3) are salient poles of the rotor 15.
At least one set is provided so that the angles differ by an integral multiple of the pitch of Ci + 1/4 pitch. Further, as shown in FIG. 6, the rotor 15 is fixed in parallel to the same shaft 17, and each bit information target Bi of the rotor 11 and the rotor 15 are fixed.
Each salient pole Ci of is at the same angle as seen in the axial direction. Here, the structure and operation of the relative angle detecting device 7 will be described in principle with reference to FIG.

The rotor 15 and the stator 16 are also formed of an electromagnetic steel plate, and the salient poles Dj of the stator 16 are phase-shifted by 1/4 pitch with respect to the salient poles Ci of the rotor 15 to provide one or several sets. Each salient pole Dj of the stator 16 has a primary winding connected in series with an oscillator 13 ′ (the oscillator 13 may be shared) and a secondary winding in which an induced electromotive force is induced. Each is wound. The primary winding is wound so that the adjacent salient poles are opposite to each other, and the secondary winding has the opposite electromotive force of the opposite poles and the difference between them is obtained as the output. These outputs are combined and taken out as a phase output and a phase output. This relative angle detecting device 7 is also adapted to take out the change in the reluctance of the magnetic path depending on the rotational position of the rotor 15 as the change in the output voltage of the secondary winding. For example, rotor 15 and stator 16
Is in the relative positional relationship as shown in FIG. 3, the secondary winding output of the salient pole D ₀ of the stator is maximum, the output of the salient pole D ₂ is minimum, and the outputs of the salient poles D ₁ and D ₃ are Somewhere in between.

Therefore, at the illustrated position, the output of the output terminal is the maximum value and the output of the terminal is 0. From this position the rotor 15
FIG. 5 shows changes in the output voltage of the output terminal and when the is rotated by 1 pitch to the right. In this way, amplitude-modulated waves are obtained at the output terminal and as the rotor 15 rotates, and their phases are deviated from each other by 1/4 pitch and 90 ° in electrical angle. If these two outputs are input to a 10-bit output R / D (resolver / digital) converter for processing, the relative angle can be displayed in units of 1024 divided by one pitch angle of the rotor 15. You can

The origin signal generator 9 of the relative angle detector 2 is the R / D converter 8
The moment when all the bits of the output of 0 become 0 (at this time, the relative angle is 0 °, and the absolute angle is one of the above 256 absolute angles.
Exactly the same)), the origin signal is issued to the aligner 5 of the absolute angle detector 1. The aligner 5 updates the absolute angle up to that point with the absolute angle represented by the output of the moment discriminating device 4 to which the origin signal is input, and outputs it to the 8-bit output unit 6. The 10-bit output representing the relative angle of the R / D converter 8 is transferred from the 10-bit output unit 10 to the lower 10-bit unit of the 18-bit output unit 14,
In this 10-bit output, shaft 17 (Fig. 6) has 1 of rotors 11 and 15
It changes from 00000000 to 1111111111 while rotating by the pitch. In this way, 18-bit output unit 14 1 ie 2 ¹⁸ minutes of one revolution by the lower 1 bit representing the relative angle of the upper 8 bits and their origin absolute angle representing the absolute angle from the absolute angle detecting unit 10 The data indicating the absolute angle is output with an extremely high resolution of 1 / 262,144 units. This output data is used as a rotation angle (position) signal of the shaft 17 by feeding it back to a control means such as a microcomputer, or by converting it into hexadecimal data and displaying it.

Next, another embodiment of the rotation angle detecting device of the present invention will be described.
This will be described with reference to the drawings and FIG. In this embodiment, the absolute angle detector and the relative angle detector can be obtained with one rotor and one stator. In this embodiment, the stator 72 is provided with a salient pole 72a as a bit information detecting portion for detecting an absolute angle and a salient pole 72b for detecting a relative angle, and a high salient pole as a bit information target is provided around the rotor 71. X and low salient poles Y are provided at equal pitch intervals. In this embodiment as well, when the high salient pole X corresponds to the bit 1 and the low salient pole Y corresponds to the bit 0, the high salient pole X and the high salient pole X correspond to all the absolute angles of the workpiece 71. 2 given by bit information of low salient pole Y
The value data has a one-to-one correspondence. The salient poles 72b for detecting the relative angle are each made up of a plurality of small salient poles 72b '.
Are provided at the same pitch interval as the salient pole pitch of the rotor 71, it is possible to suppress the change in the reluctance of the magnetic circuit between the rotor 71 and the rotor 71 at any rotation position. .

In FIG. 8, the circumference of the rotor 71 is divided into 256 equal parts to provide the high salient poles X and the low salient poles Y as described above, and the stator 72 has eight salient poles 72a for absolute angle detection and eight relative angle detections. The rotation angle detection device provided with salient poles 72b for use in the development is shown in a straight line. In this embodiment, the primary windings of the salient pole 72a for detecting the absolute angle and the salient pole 72b for detecting the relative angle of the stator 71 are commonly excited by the oscillator 73. Eight bit information outputs s ₀ , ..., s ₈ are taken out from the secondary windings of the salient poles 72a for absolute angle detection,
The output of the secondary winding of the relative angle detecting salient pole 72b is combined into a terminal and two outputs of the terminal. By processing these outputs in the same manner as in the above embodiment, one rotation of 2 ¹⁸ = 262144.
It is possible to detect the absolute angle with extremely high resolution of one-half.

Furthermore, in another embodiment of the present invention shown in FIG. 9, instead of providing the absolute angle detecting salient pole 72a as in the embodiment of FIGS. 7 and 8 described above, the relative angle detecting salient pole 72a is provided. Pole 7
One 72b ″ of the small salient poles 72b ′ of 2b is also used as the absolute angle detecting salient pole. In this embodiment, the primary winding of the relative angle detecting salient pole 72b is used as the absolute angle detecting secondary pole. It can also be used for exciting the winding 72c.
This is exactly the same as the case of the embodiment shown in FIGS. 7 and 8.

〔The invention's effect〕

The rotation angle detection device of the present invention is capable of detecting an absolute angle with high accuracy and high resolution despite the fact that the structure is simple and inexpensive, and therefore various machines having a rotating part driven by a motor or the like, It is obvious that it can make a great contribution to the performance improvement and cost reduction of the rotation control of the device.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a rotation angle detecting device of the present invention, and FIGS. 2 and 3 are explanatory diagrams for explaining the principles of the absolute angle detecting device and the relative angle detecting device, respectively. FIGS. 5 and 5 are waveform diagrams showing the output waveforms of FIGS. 2 and 3, respectively, and FIG. 6 is an explanatory diagram showing an example of the mounting arrangement of the absolute angle detection device and the rotation angle detection device, and FIG.
FIG. 8 and FIG. 8 are explanatory views of another embodiment of the rotation angle detecting device of the present invention, and FIG. 9 is an explanatory view of still another embodiment of the rotation angle detecting device of the present invention. 1 ... Absolute angle detector, 2 ... Relative angle detector, 3 ... Absolute angle detector, 7 ... Relative angle detector, 11, 71 ... Rotor, 12, 72 ... Stator, Bi (i = 0 ........., n-1)
... Bit information target, Sj (j = 0, ..., m-
1) ... Bit information detector.

Claims (1)

(57) [Claims] 1. A bit information target Bi (i = 0) which carries bit information at each equally dividing point Pi (i = 0, ..., N-1) obtained by dividing the circumference into n equal parts (n is an integer of 3 or more). , ……, n-
The decimal number n for detecting the bit information of the rotor provided with 1) and the bit information target Bi of the rotor, respectively.
A stator provided with m (where m is an integer of 2 or more) bit information detection units Sj (j = 0, ..., M-1), which is equal to or larger than the number of digits of the binary display of -1. The information of the bit information target Bi of the rotor is the rotation angle detecting device provided such that the n pieces of m-bit data detected by the stator information detecting unit Sj by the rotation of the rotor are all different from each other. An absolute angle detecting device for detecting n absolute angles respectively corresponding to the n binary data taken at any one time; and a stator having n absolute angles detected by the absolute angle detecting device as reference points. The relative angle with the rotor is l
It is equipped with a relative angle detection device that detects by 1 unit of 2 ^l (l is a positive integer) based on binary data of bits, and detects an absolute angle by 1 unit of 2 ^{n + l of} one rotation. A rotation angle detecting device characterized in that