JP3448664B2 - Multi-turn absolute encoder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-turn absolute encoder, and more particularly to a method for resetting a multi-turn absolute encoder.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing the structure of a conventional multi-rotation absolute encoder. The illustrated multi-rotation absolute encoder is a multi-rotation amount system circuit block for obtaining and outputting multi-rotation amount data Q based on a signal detected from a pattern formed on a code plate (not shown) provided on a rotary shaft. 10 and absolute address data R within one rotation based on a signal detected from another pattern of the code plate
It is provided with an absolute address system circuit block 13 within one revolution for obtaining and outputting.

The illustrated multi-rotation absolute encoder further includes a multi-rotation number correction circuit 16 for correcting the multi-rotation amount data Q, and the multi-rotation amount data S corrected by the multi-rotation number correction circuit 16 and an absolute value within one revolution. The data output circuit 17 receives the absolute address data R within one rotation from the address system circuit block 13. The data output circuit 17 includes the corrected multi-rotation amount data S and the absolute address data R within one rotation.
And are internally latched, and an external (serial) output signal t corresponding to the absolute position of the code plate is transmitted.

The multi-rotation amount system circuit block 10 includes a magnetic encoder 11 and a backup system rotation amount holding / counting circuit 1.
It consists of 2. Backup system rotation amount holding / counting circuit 1
The multi-revolution amount correction circuit 16 receives multi-revolution amount data Q obtained based on the incremental two-phase (A-phase and B-phase) signals n and o output from the magnetic encoder 11 via the multi-revolution amount data bus. Send out. The multi-rotation amount system circuit block 10 is driven by an external battery or a large-capacity capacitor (hereinafter referred to as “external battery”) inside the encoder even when the main power source of an external controller (not shown) is turned off, and even when power supply is stopped. Is configured to work.

On the other hand, an absolute address system circuit block 1 within one rotation
3 comprises an optical encoder 14 and a data conversion circuit 15. The data conversion circuit 15 includes an optical encoder 14
Absolute address data R within one revolution obtained based on the absolute value data signal (absolute signal) p within one revolution and the incremental two-phase signals (A phase and B phase) within one revolution q and r output by The data is sent to the data output circuit 17 via the inner absolute address data bus. The absolute address system circuit block 13 within one rotation is configured to be driven by the main power source of the external controller and stop its operation when the power supply is stopped.

[0006]

In the conventional multi-rotation absolute encoder as described above, the output signals n and o of the magnetic encoder 11 are two-phase signals of one rotation and one pulse output. An MR sensor is used. However, it is difficult to control the placement accuracy (detection side) of the MR sensor and the sticking position accuracy (pattern side) of the magnet. Therefore, a minute error occurs between the position information detected by the optical encoder 14 and the multi-rotation speed detected by the magnetic encoder 11. As described above, it is generally very difficult to eliminate the above-mentioned error caused by the placement accuracy (detection side) of the MR sensor and the sticking position accuracy (pattern side) of the magnet.

In the conventional multi-rotational absolute encoder as described above, since the priority of the position information is on the absolute value side within one revolution, the multi-rotation number is ± 1 at maximum at the switching point of the multi-rotation number as described later. It's just a mistake. In order to prevent the malfunction of the multi-rotation speed, the multi-rotation speed correction circuit 16 performs an operation of increasing or decreasing the multi-revolution data detected by the magnetic encoder 11 by ± 1 at the time of switching the multi-rotation speed, that is, a correction operation. There is a need. FIG. 5 is a diagram for explaining a correction operation in the multiple rotation speed correction circuit 16.

In FIG. 5, (1) shows the number of multiple revolutions obtained based on the increase / decrease in absolute value data p within one revolution detected by the optical encoder. For example, in the case of an absolute encoder with a resolution of 3 bits per revolution, the number of multiple revolutions becomes 1 when the absolute value within 1 revolution becomes 0 from 5, 6, 7
If it is incremented (increased) only, it is possible to obtain the number of multiple revolutions synchronized with the absolute value data within one revolution of the optical encoder. On the contrary, the absolute value within one rotation is 2, 1, 0.
By decrementing (decreasing) the number of revolutions by 1 at the time point from 7 to 7, the number of revolutions synchronized with the absolute value data within one revolution of the optical encoder can be obtained.

(2) shows a value obtained by extracting the upper 2 bits of the absolute value data p within one rotation and converting it into decimal data. In other words, it indicates a value obtained by dividing the absolute value within one rotation into four. (3) indicates the number of multiple revolutions detected by the magnetic encoder. In (4), the two-phase rectangular wave of the magnetic encoder corresponding to one pulse output per rotation is subjected to code conversion so as to be ascending 2-bit binary data, and then 10
It is expressed in radix. In other words, it corresponds to a value obtained by dividing the multi-rotation amount data of the magnetic encoder into four.

(5) shows the correction operation in the multi-rotation speed correction circuit 16 of FIG. The correction operation will be described later with reference to FIG. (6) shows the multi-rotation amount data corrected by the multi-rotation number correction circuit 16. FIG. 6 is a truth table for determining the correction operation in the multi-rotation speed correction circuit 16. As shown in FIG. 6, in the 2-bit data obtained by converting the two-phase signal of the magnetic encoder into a binary number, the upper bit is 1 and the lower bit is 1 (that is, 10 bits).
(3) in decimal, and when the most significant bit (MSB) v of the upper 2 bits of the absolute value within one rotation of the optical encoder is 0 and the next upper bit w is 0 (that is, 0 in decimal) ( (Indicated by diagonal lines in the figure), the multi-revolution speed correction circuit 16 performs a correction operation of +1.

In the 2-bit data obtained by converting the two-phase signal of the magnetic encoder into a binary number, the upper bit is 0 and the lower bit is 0 (that is, a decimal number is 0), and within one rotation of the optical encoder. Of the upper two bits of the absolute value, the most significant bit (MSB) v is 1 and the next higher bit w is 1.
When it is 3 (decimal number), the multi-rotation speed correction circuit 1
At 6, the correction operation of -1 is performed. In other cases, the correction operation is not performed in the multi-rotation speed correction circuit 16.

On the other hand, FIG. 7 shows a multi-rotation amount system circuit block 1
0 is a multi-rotation speed reset command signal u from the external controller
FIG. 9 is a diagram illustrating a multi-rotational speed reset operation when receiving a signal. In FIG. 7, (11) is the number of multiple revolutions obtained based on the increase / decrease in the absolute value data within one revolution detected by the optical encoder, and corresponds to (1) in FIG.

(12) shows a value obtained by extracting the upper 2 bits of the absolute value data within one rotation and converting it into decimal data. In other words, it is a value obtained by dividing the absolute value within one rotation into four, and corresponds to (2) in FIG. (13) is the multi-rotation speed detected by the magnetic encoder, and corresponds to (3) in FIG. In (14), the two-phase rectangular wave of the magnetic encoder corresponding to one pulse output per rotation is subjected to code conversion so as to become ascending 2-bit binary data, and then 10
It is expressed in radix. In other words, it corresponds to a value obtained by dividing the multi-rotation amount data of the magnetic encoder into four, and corresponds to (4) in FIG.

(15) is output from the multi-revolution amount system circuit block 10 when a multi-revolution number reset command is input from the external controller to the backup system revolution amount holding / counting circuit 12 at the time point indicated by the arrow in FIG. The multi-rotation amount data Q is shown. As shown in the figure, the multi-rotation speed reset command resets the multi-rotation speed to zero. (1
6) shows the correction operation in the multiple rotation speed correction circuit 16 of FIG. That is, it corresponds to (5) in FIG. (17) shows the output multi-revolution amount data of the multi-revolution correction circuit 16 when the reset command is input at the time point indicated by the arrow in FIG. 7.

As shown in FIG. 7, the multi-revolution reset command resets the multi-revolution output from the multi-revolution system circuit block 10 to 0, but the multi-revolution corrected by the multi-revolution correction circuit 16 is corrected. Quantity data is +1 by correction operation
Becomes That is, despite the multi-rotation speed reset command, the multi-rotation data that is not reset to “0” is input to the data output circuit 17 due to the correction operation in the multi-rotation correction circuit 16. In other words, the conventional multi-rotation absolute encoder has a disadvantage that the multi-rotation number, which should be 0, becomes "+1" or "-1" depending on the position where the multi-rotation number reset command is input. It was

The present invention has been made in view of the above-mentioned problems, and it is possible to reliably reset the multi-rotation number in response to the multi-rotation number reset command even if the correction operation of the multi-rotation amount data is performed. An object is to provide a rotary absolute encoder.

[0017]

In order to solve the above problems, in the present invention, a code plate on which a first pattern and a second pattern are formed, and the first pattern is read,
A first detector that outputs information about one rotation of the code plate;
A second detector that reads the second pattern and outputs first multi-rotation information of the code plate, and the first multi-rotation information for synchronizing the first-revolution information and the first multi-rotation information. Correction means for correcting information and outputting corrected multi-rotation information, reset means for outputting a reset signal for resetting the corrected multi-rotation information to a predetermined value, and inputting the reset signal, the corrected multi-rotation information On the basis of the multi-revolution information presetting means for presetting a predetermined value to the first multi-rotation information from the second detection unit, and the in-one-revolution information and the corrected multi-revolution information so that , and a data output means for outputting the multiple rotation absolute position information of the code plate, the multi-rotation information preset means, the correction
When the method corrects "+1", the value "-1" is
Outputs a first command signal for resetting to the second detection unit
However, when the correction means corrects "-1", "+"
The second command signal for presetting the value of "1" is set to the second command signal.
When output to the detection unit and the correction means does not perform correction
Is a third command signal for presetting a value of "0".
Provided is a multi-rotation absolute encoder, which outputs to two detectors .

According to a preferred embodiment, the correction means is
In order to synchronize the second multi-rotation information detected based on the increase / decrease in the one-revolution information and the first multi-rotation information,
The first multi-rotation information is corrected and the corrected multi-rotation information is output.

[0019]

In the multi-rotation absolute encoder of the present invention, when the reset signal is input, the first multi-rotation information from the second detection unit is set to a predetermined value so that the output of the correction unit becomes a predetermined value (for example, zero). The multi-rotation information presetting means for presetting the value of That is, when the multi-rotation speed reset command is input, the multi-rotation information presetting unit presets, for example, “+1”, “0” and “−1” according to the position where the multi-rotation speed reset command is input. Output a command signal.

Specifically, when a multi-rotational speed reset command is input in a region where the correcting means performs a +1 correcting operation, the output of the second detecting portion is preset to "-1" and input to the correcting means. To do. As a result, the output of the correction means becomes "0". Further, when the multi-rotational speed reset command is input in the region where the correcting unit performs the correcting operation of -1, the output of the second detection unit is preset to "+1" and input to the correcting unit. As a result, the output of the correction means becomes "0".

Further, when a multi-rotational speed reset command is input in a region where the correcting means does not perform the correcting operation, the output of the second detector is preset to "0" and input to the correcting means. As a result, the output of the multi-rotation amount data correction means becomes "0". As described above, in the multi-rotation absolute encoder of the present invention, the output of the second detection unit is changed to "+" according to the position where the multi-revolution reset command is input.
Since the preset values are appropriately set to "1", "0", and "-1", the multi-rotation information corrected by the correction means is surely "0" by the reset command.

[0022]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block configuration diagram of a multi-turn absolute encoder according to an embodiment of the present invention. The multi-rotation absolute encoder shown in the drawing is based on a signal detected from a pattern formed on a code plate (not shown) fixed to a rotary shaft, and multi-rotation amount data D which is multi-rotation information of the code plate.
The multi-rotation amount system circuit block 1 for obtaining and outputting The multi-rotation amount system circuit block 1 is composed of a magnetic encoder 2 using an MR sensor (magneto-resistive sensor), for example, and a backup system rotation amount holding / counting circuit 3 in the detecting section. The backup system rotation amount holding / counting circuit 3 includes an incremental two-phase (A
Phase and B phase) The multi-revolution amount data D obtained based on the signals a and b is sent to the multi-revolution number correction circuit 8 via the multi-revolution amount data bus. In addition, the multi-rotation amount system circuit block 1
Is driven by the external battery even when the main power supply of the external controller (not shown) is turned off, and is operated even when the power supply is stopped.

Further, the illustrated multi-rotation absolute encoder calculates and outputs absolute address data E within one revolution, which is information within one revolution of the code plate, based on a signal detected from another pattern formed on the code plate. An absolute address system circuit block 4 for one rotation is provided. The absolute address system circuit block 4 within one rotation includes an optical encoder 5 and a data conversion circuit unit 6. The data conversion circuit unit 6 obtains the absolute value data signal within one revolution (absolute signal) c output from the optical encoder 5 and the incremental two-phase signal within one revolution (A phase and B phase) d and e. The absolute address data E within one revolution is sent to the data output circuit 9 via the absolute address data bus within one revolution.

Further, the data conversion circuit section 6 sends the most significant bit 1 and the next most significant bit m of the absolute address data E within one revolution to the multi revolution number preset value control circuit 7. On the other hand, the magnetic encoder 2 is the magnetic encoder 2
And outputs the incremental two-phase (A-phase and B-phase) signals a and b to the multi-rotation preset value control circuit 7. The multi-rotation preset value control circuit 7 uses a multi-rotation reset command h from an external controller.
In response, the preset command signal i of "+1", the preset command signal j of "0" or the preset command signal k of "-1" is output to the backup system rotation amount holding / counting circuit 3.

The multi-revolution correction circuit 8 corrects the multi-revolution data D from the multi-revolution system circuit block 1 as described later. The data output circuit 9 multi-rotates the code plate based on the multi-rotation amount data F corrected by the multi-rotation number correction circuit 8 and the one-revolution absolute address data E from the one-revolution absolute address system circuit block 4. An external (serial) output signal g that is absolute position information is sent to an external controller. In addition, the absolute address system circuit block 4 within one rotation is configured to be driven by the main power source of the external controller and stop its operation when the power supply is stopped.

FIG. 8 and FIG. 9 are a plan view and a side view schematically showing the specific structures of the magnetic encoder section and the optical encoder section in the multi-turn absolute encoder of FIG. Code plate 2 fixed to the rotary shaft 31
In FIG. 4, a first track 21 having an absolute pattern, a second track 22 having an incremental pattern, and a third track 23 for counting the number of revolutions for generating one pulse per revolution are independently formed concentrically. ing. The first and second tracks 21 and 22 are optical black and white patterns, and the track 23 is a magnetic S pattern.
N patterns.

The magnetic encoder section, which is a rotation counting detector, detects 1 along the third track 23.
It is composed of an MR sensor 27 that generates one pulse for rotation.
The signal output from the MR sensor 27 is the above-described incremental two-phase (a-phase and B-phase) signals a and b.
become. In addition, the optical encoder unit includes the second track 22.
Incremental two-phase signals d and e within one revolution along
And an absolute detection section 25 for detecting the absolute value data c within one rotation along the first track 21.

The incremental two-phase signals a and b detected by the magnetic encoder unit 27 are output to the backup system rotation amount counting / holding circuit 3 via the terminal 30.
The absolute value data c within one rotation detected by the absolute detection unit 25 is output to the data conversion circuit unit 6 via the terminal 28. Further, the incremental detector 26
The in-one-revolution incremental two-phase signals d and e detected in 1 are output to the data conversion circuit unit 6 via the terminals 29A and 29B.

The multi-rotation speed correction operation and the preset operation in response to the multi-rotation speed reset command of the multi-rotation absolute encoder of the present embodiment having the above configuration will be described with reference to FIGS. 2 and 3. FIG. 2 is a diagram for explaining the multiple rotation speed correction operation and the preset operation. In FIG. 2, (21) indicates the number of multiple revolutions obtained based on the increase / decrease in the absolute value data c within one revolution detected by the optical encoder. For example, in the case of an absolute encoder with a resolution of 1 rotation 3 bits, the absolute value within 1 rotation is 5, 6, 7
If the number of revolutions is incremented (increased) by 1 when the value becomes 0 from 0, the number of revolutions synchronized with the absolute value data within one revolution of the optical encoder can be obtained. Also,
On the contrary, if the number of revolutions is decremented by 1 when the absolute value within one revolution changes from 2, 1, 0 to 7, the multiple revolution synchronized with the absolute value data within one revolution of the optical encoder is performed. The number can be calculated.

(22) shows a value obtained by extracting the upper 2 bits of the absolute value data c within one rotation and converting it into decimal data. In other words, it indicates a value obtained by dividing the absolute value within one rotation into four. (23) indicates the number of multiple revolutions detected by the magnetic encoder. (24) shows the two-phase rectangular waves a and b of the magnetic encoder corresponding to one-rotation one-pulse output, which are code-converted so as to be ascending 2-bit binary data and are expressed in decimal. . In other words, it corresponds to a value obtained by dividing the multi-rotation amount data of the magnetic encoder into four.

(25) is output from the multi-revolution amount system circuit block 1 when a multi-revolution reset command is input from the external controller to the multi-revolution preset value control circuit 7 at the time point indicated by the arrow in FIG. The multi-rotation amount data D is shown. As shown in the figure, the multi-revolution speed reset command presets the multi-revolution speed to -1. The preset operation will be described later with reference to the truth table of FIG. (26) shows the correction operation in the multiple rotation speed correction circuit 8 of FIG. The correction operation will be described later with reference to the truth table of FIG. (27) shows the output multi-revolution amount data F of the multi-revolution correction circuit 8 when the reset command is input at the time point indicated by the arrow in FIG.

As shown in FIG. 3, the magnetic encoder 2
Of the 2-bit data obtained by converting the phase signals a and b into binary numbers, the upper bit is 1 and the lower bit is 1 (that is, 3 in decimal), and the upper 2 bits of the absolute value within one rotation of the optical encoder are Among them, when the most significant bit (MSB) f is 0 and the next higher bit m is 0 (that is, a decimal number 0) (indicated by diagonal lines in the drawing), the multi-rotation speed correction circuit 8 performs a correction operation of +1. Therefore, when the multi-revolution speed preset value control circuit 7 receives the multi-revolution speed reset command h from the external controller in this region, the multi-revolution speed preset value control circuit 7 sends the preset command signal k of "-1" to the backup system rotation amount. Output to the holding / counting circuit 3. As a result, the backup system rotation amount holding / counting circuit 3 is preset to "-1" as multi-rotation amount data.
Is output to the multi-rotation speed correction circuit 8. Multi revolution number correction circuit 8
Then, since the correction operation of +1 is performed as described above, the output of the multi-rotation speed correction circuit 8 becomes "0" at the time of receiving the external reset command h.

On the other hand, the two-phase signals a and b of the magnetic encoder
Of the 2-bit data converted to binary, the upper bit is 0 and the lower bit is 0 (that is, 0 in decimal),
In addition, when the most significant bit (MSB) f of the upper two bits of the absolute value within one rotation of the optical encoder is 1 and the next upper bit m is 1 (that is, 3 in decimal), the multi-rotation speed correction circuit 16 The correction operation of -1 is performed. Therefore, in this region, the multi-rotation preset value control circuit 7
When the multi-revolution speed reset command h is received from the external controller, the multi-revolution speed preset value control circuit 7 indicates “+
The preset command signal i of "1" is output to the backup system rotation amount holding / counting circuit 3. As a result, the backup system rotation amount holding / counting circuit 3 outputs "+1" preset as multi-rotation amount data to the multi-rotation number correction circuit 8.
Since the multi-revolution correction circuit 8 performs the correction operation of -1 as described above, the output of the multi-revolution correction circuit 8 becomes "0" when the external reset command h is received.

Further, in other cases, the correction operation is not performed in the multi-rotation speed correction circuit 16. Therefore, when the multi-revolution speed preset value control circuit 7 receives the multi-revolution speed reset command h from the external controller in this region, the multi-revolution speed preset value control circuit 7 holds the preset command signal j of "0" in the backup system rotation amount. -Output to the counting circuit 3. As a result, the backup system rotation amount holding / counting circuit 3 outputs “0” preset as multi-rotation amount data to the multi-rotation number correction circuit 8.
Since the multi-rotational speed correction circuit 8 does not perform the correction operation as described above, the output of the multi-rotational speed correction circuit 8 becomes "0" when the external reset command h is received.

In the above embodiments, the present invention has been described with respect to the absolute encoder having the magnetic encoder as the multi-rotation detecting section and the optical encoder as the absolute detecting section and the incremental detecting section. It goes without saying that it is not limited to.

Further, although the optical encoder section of this embodiment is provided with the incremental pattern, it may be constructed with only the absolute pattern. In this case, the absolute address data E within one revolution may be obtained from the absolute value data signal within one revolution read and output from the absolute pattern.

[0037]

As described above, according to the multi-turn absolute encoder according to the first aspect of the present invention, even if the multi-rotation reset command is received during the multi-rotation correction operation, the corrected multi-rotation speed is corrected. Can be reliably reset to "0".

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a multi-turn absolute encoder according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a multi-rotation speed correction operation and a multi-rotation speed preset operation of the multi-rotation absolute encoder according to the present embodiment.

FIG. 3 is a truth table for a multi-rotation speed correction operation and a multi-rotation speed preset operation of FIG.

FIG. 4 is a block diagram showing the configuration of a conventional multi-turn absolute encoder.

FIG. 5 is a diagram for explaining a multi-rotation speed correction operation of a conventional multi-rotation absolute encoder.

FIG. 6 is a diagram showing a truth value that determines a multi-rotation speed correction operation of FIG. 5;

FIG. 7 is a diagram illustrating a reset operation of a conventional multi-rotation absolute encoder.

8 is a plan view schematically showing specific configurations of a magnetic encoder section and an optical encoder section in the multi-turn absolute encoder of FIG. 1. FIG.

9 is a side view schematically showing specific configurations of a magnetic encoder section and an optical encoder section in the multi-turn absolute encoder of FIG. 1. FIG.

[Explanation of symbols]

1, 10 Multiple rotation amount system circuit block 2, 11 Magnetic encoder 3, 12 Backup system rotation amount counting / holding circuit 4, 13 1 rotation absolute address system circuit block 5, 14 Optical encoder 6, 15 Data conversion circuit 7 Multi revolution number preset value control circuit 8, 16 Multi revolution number correction circuit 9, 17 Data output circuit a, b, n, o Multi revolution amount incremental two-phase signal c, p 1 revolution absolute value data signal (absolute signal) d , E, q, r Incremental two-phase signal in one rotation i, j, k Preset command signal f, v Most significant bit of absolute value data in one revolution m, w Next higher bit of absolute value data in one revolution

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Ono 471 Nagaodai-cho, Sakae-ku, Yokohama-shi, Kanagawa Nikon Corporation Yokohama Works (56) Reference JP-A-3-287014 (JP, A) JP-A-6 −147814 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01D 5 / 00-5 / 62

Claims (2)

(57) [Claims] 1. A code plate on which a first pattern and a second pattern are formed, a first detection unit that reads the first pattern and outputs information about one rotation of the code plate, and the second pattern. To detect the first multi-rotation information of the code plate and to synchronize the first multi-rotation information with the second detection unit that outputs the first multi-rotation information of the code plate. Correcting means for outputting the corrected multi-rotation information, reset means for outputting a reset signal for resetting the corrected multi-rotation information to a predetermined value, and inputting the reset signal, the corrected multi-rotation information reaches a predetermined value. As described above, based on the multi-rotation information presetting unit that presets a predetermined value in the first multi-rotation information from the second detection unit, and the one-revolution-in-information and the corrected multi-rotation information,
And a data output means for outputting the multiple rotation absolute position information of the code plate, the multi-rotation information preset means, the correction means "+
When correcting "1", preset the value of "-1".
Output a first command signal to the second detector,
When the corrector corrects "-1", the value of "+1" is
The second command signal for presetting is output to the second detector.
When the correction means does not make a correction, the value of "0"
The third command signal for presetting a value is used as the second detection unit.
A multi-turn absolute encoder that is characterized by outputting to . 2. The correction means sets the first multi-rotation information in order to synchronize the second multi-rotation information detected based on the increase / decrease of the information within the one-revolution with the first multi-rotation information. The multi-turn absolute encoder according to claim 1, wherein the multi-turn absolute encoder corrects and outputs corrected multi-turn information.