JP2000018970A - Angle detecting device and car using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable detection of a rotation angle with high resolution in a wide range by installing a plurality of pickups producing a code that determines a rotation angle of a disk, so as to be disposed facing to a code pattern placed on a circumference of the disc and converting the code into the rotation angle of the disc. SOLUTION: A pickup fixing part 19, a multiple rotation detection disc 18, a one-rotation detecting disc 17, and a deceleration gear wheels 15a-15d are installed between an upper case 14 and a lower case 16, where the multiple rotation detecting disc 18 is united so as to be rotatable with respect to the one-rotation detecting disc 17 at a deceleration ratio. The one-rotation detection disc 17 is constituted, so that the disc 17 rotates in linkage with a measured object, and therefore a rotation angle of the measured object can be detected by detecting the rotation angle of the disc 17. For example, the pickup fixing part 19 is installed, so as to be held between the detecting disc 17 and the detecting disc 18 when it is a steering for a car.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for detecting a rotation angle, and more particularly to an absolute type angle detection device used for detecting a rotation angle of a steering of an automobile and an automobile using the same.

[0002]

2. Description of the Related Art As a conventional rotation angle detecting means, there is known an increment operation type angle detecting device in which an angle increment section is provided in only one track. Further, as described in Japanese Patent Application Laid-Open No. Hei 8-511350, an absolute type angle detecting device includes a means for detecting an angle within one rotation and a number of rotations for a rotation exceeding one rotation. There is a combination with a means for detecting whether an eye is detected using a gray code.

[0003]

However, the conventional angle detecting device has the following problems.

For certain safety devices in vehicles (eg automatic rear axle steering, driving dynamics control), for safety reasons, the actual steering wheel position is required immediately after the vehicle ignition switch is turned "ON". You. In this case, an increment operation type sensor in which the angle increment section is provided in only one track cannot sufficiently satisfy this requirement. This is because before any sensor can provide a valid measurement, access to one index mark must be obtained anyway. Further, a steering wheel angle sensor of an automobile is usually required to measure a measured value of four or more rotations. This means that a second device for detecting a rotation angle exceeding one rotation must be provided in this sensor. This second device must also supply a valid value immediately after the ignition switch "ON".

The absolute type angle detecting device described in Japanese Patent Laid-Open Publication No. Hei 8-511350 solves the problem of angle detection immediately after the ignition switch is turned "ON", but it does not solve the problem. Since a magnet as a sensor must be arranged over 360 ° on the outside, it is difficult to reduce the size of the device.

The present invention has been made to solve the above-mentioned problems, and realizes a reduction in size, a rotation angle is determined in an initial state, and the rotation angle is detected in a non-contact manner. It is another object of the present invention to provide an angle detection device capable of detecting an abnormality of a pickup without any problem.

[0007]

In order to achieve the above object, an angle detecting device according to the present invention comprises a disk rotatable in forward and reverse directions, a code pattern provided on a circumference of the disk, and a code pattern. A plurality of pickups, which are provided on the same circumference of the rotation axis of the disk so as to face the disk and read a code pattern and generate a code for determining the rotation angle of the disk, and a conversion for converting the code into the rotation angle of the disk And one rotation angle detecting means. As a result, it is not necessary to provide a pickup outside the disk, and the size of the apparatus can be reduced.
In addition, the code generated from the pickup is a code that uniquely determines the rotation angle, so that the rotation angle is known in the initial state, and since the optical element can be used for the pickup, it is possible to prevent a decrease in reliability, By supplying a code not used for determining the rotation angle to the conversion means when an abnormality occurs in the output of the pickup,
It is possible to provide an angle detection device capable of detecting a pickup abnormality.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION
A disk rotatable in the forward and reverse directions, a code pattern provided on the circumference of the disk, and provided on the same circumference of the rotation axis of the disk so as to face the code pattern,
It includes a plurality of pickups for reading a code pattern and generating a code for determining the rotation angle of the disk, and one rotation angle detection means for converting the code to the rotation angle of the disk. This has the effect of obtaining the sign that determines the rotation angle without arranging the pickup outside the disk, thereby realizing miniaturization.

According to a second aspect of the present invention, there is provided a disk rotatable in forward and reverse directions, a plurality of rows of code patterns provided on different circumferences of the disk, and a rotation center axis of the disk opposed to the code pattern. At least one or more concentric circles, the pickup rows having a number of rows equal to the number of rows of the code patterns, reading the code patterns, and generating pickup codes for determining the rotation angle of the disk; And a one-rotation angle detecting means comprising a converting means for converting an angle code which uniquely determines the rotation angle of the disc into a rotation angle of the disc by combining the codes supplied from the above. This has the effect of obtaining a sign that determines the rotation angle without arranging the pickup outside the disk.

The invention according to claim 3 is the angle detecting device according to claim 2, wherein each code supplied from each pickup row is a gray code. This allows
This has an effect that an accurate angle detection can be performed even if a deviation occurs in the code detection timing.

According to a fourth aspect of the present invention, when the rotation angle is set such that two or more of the codes supplied from the pickup arrays change, the conversion means actually changes two or more of the codes. 4. The angle detecting device according to claim 3, wherein the rotation angle is not updated until the rotation angle is reached. Accordingly, even if the angle code is not a gray code, an accurate angle detection can be performed even if a deviation occurs in the code detection timing.

According to the fifth aspect of the present invention, when a code having a shorter cycle of change among two or more codes is set as a lower digit code, and a code having a longer cycle after the lower digit is set as an upper digit code, The sign of each digit updated to the sign of each detected digit is compared, and when the sign of the sign of the lower digit is the rotation angle of the setting at which two or more signs change, the sign of the sign of the upper digit is changed. When there is no change, the sign of each digit is not updated. When there is a change in the sign of the upper digit, at least the sign of the changed digit is updated to the detected code. 5. The angle detecting device according to claim 4, wherein, if the rotation angle is not the set rotation angle, the code of at least the digit that has changed is updated to the detected code. As a result, even if the angle code is not a gray code and the timing of code detection is shifted, accurate angle detection can be performed by a simple method.

According to a sixth aspect of the present invention, a code having a short change period among two or more codes is defined as a lower digit code, and a code having a long change period among two or more codes is defined as an upper digit code. A first register for storing a code supplied by constantly detecting the code pattern from the pickup, and a second register for storing the code of each digit updated last and supplying the code to the conversion means. And the sign of the first register and the second
And the updating means for inputting the code of the first register to the second register to update the code, and the comparing means detects the change of the lower digit by 2
In the case of the setting rotation angle where the above sign changes,
If the sign of the upper digit has changed, the second
When the sign of the upper digit is not changed, the sign of the second register is not updated, and the change of the lower digit is not the rotation angle set so that the sign of two or more changes by the comparing means. 5. The angle detecting device according to claim 4, wherein in the case, the updating means updates the sign of the second register.
Thus, with a simple configuration, even if the angle code is not a gray code, an accurate angle detection can be performed even if the code detection timing is shifted.

According to a seventh aspect of the present invention, there is provided a disk rotatable in forward and reverse directions, a code pattern provided in n-1 rows on the circumference of the disk, and a code pattern arranged opposite to the code pattern. And a conversion means for converting the code into a disk rotation angle, wherein the code is a multi-rotation angle of 2 n gray codes. It includes detection means. As a result, even if the disk has a smaller number of rows of code patterns than in the past, it has the effect of detecting the rotation angle in the same manner as in the past, and the device can be downsized.

The invention according to claim 8 is characterized in that a disc rotatable in the forward and reverse directions, a code pattern provided in n-1 rows on different circumferences of the disc, and a code pattern are arranged so as to face the code pattern. It has n pickups for reading patterns and generating an n-bit code that is a gray code that determines the rotation angle of the disk, and conversion means for converting the code to the rotation angle of the disk. It consists of a configuration in which two out of n pickups are used to detect a code pattern for supplying a code of a bit that changes in a long cycle, and one remaining pickup is provided for each of the remaining code patterns. Is an angle detecting device including a multi-rotation angle detecting means for supplying the n-th code. As a result, even if the disk has a smaller number of rows of code patterns than in the past, it has the effect of detecting the rotation angle in the same manner as in the past, and the device can be downsized.

According to a ninth aspect of the present invention, in the multi-rotation angle detecting means, the code of the i-th bit changes in a cycle twice as long as the code of the (i-1) -th bit, and The phase of the code is shifted by 1/4 cycle of the code of the (i-1) th bit, the code of the nth bit changes in the same cycle as the code of the (n-1) th bit, and n- 1/1 of the code of the (n-1) th bit with respect to the phase of the code of the first bit
9. The angle detecting device according to claim 8, wherein the angle is shifted by four periods (where 2 ≦ i ≦ n−1). This makes it easy to convert 2 n gray codes into n-
It has an effect that can be created by a single row of code patterns.

The invention according to claim 10 is the invention according to claims 1 to 5
In the angle detecting device according to any one of the above, a multi-rotation angle detecting means that rotates in conjunction with the one-rotation angle detecting means and supplies a code that uniquely defines the rotation angle is added, and the one-rotation angle detecting means and the multi-rotation This is an angle detection device that detects a rotation angle by a conversion means provided in one rotation angle detection means using a code supplied from the angle detection means. As a result, the rotation angle of the disk over multiple rotations can be detected with high resolution, and the size of the apparatus can be reduced.

According to an eleventh aspect of the present invention, the multi-rotation angle detecting means includes a disk rotatable in forward and reverse directions, a code pattern provided in n-1 rows on the circumference of the disk, and a code pattern. 11. The angle detecting device according to claim 10, further comprising: n pickups arranged so as to read a code pattern and generate a code for determining a rotation angle of the disk. This has the function of detecting the rotation angle of the disk over multiple rotations with high resolution, and can realize the miniaturization of the apparatus.

According to a twelfth aspect of the present invention, the disk of the multi-rotation angle detecting means is connected at a predetermined reduction ratio so as to rotate more slowly than the disk of the single rotation angle detecting means. Angle detection device. This has the function of detecting the rotation angle of the disk over multiple rotations with high resolution, and can realize the miniaturization of the apparatus.

According to a thirteenth aspect of the present invention, there is provided the angle detecting device according to the tenth aspect, wherein a code pattern having the longest cycle among a plurality of code patterns is provided on the outermost periphery of the disk. This has the effect of preventing the strength of the disc from decreasing.

According to a fourteenth aspect of the present invention, in the case where an abnormality occurs in the output of the pickup, a code not used for determining the rotation angle is supplied to the conversion means. Item 11. An angle detection device according to item 10. This has the effect of detecting when the pickup is abnormal.

According to a fifteenth aspect of the present invention, the pickup is electrically connected in series except for a signal line for supplying a detected code pattern, and uses all 0s or all 1s for codes not used to determine the rotation angle. An angle detecting device according to claim 14, wherein: Thus, when any one of the pickups has an abnormality, it has an operation of detecting the abnormality.

According to a sixteenth aspect of the present invention, when an abnormality occurs in the output of the pickup, the pickup uses a code that is not used to determine the rotation angle by changing the angle corresponding to one cycle of the shortest cycle code pattern. 11. The angle detecting device according to claim 10, wherein the angle is supplied at least once during the rotation. Thus, when an abnormality occurs in the pickup, the abnormality is detected by rotating the angle corresponding to the cycle with the shortest sign change.

According to a seventeenth aspect of the present invention, one pickup in an arbitrary pickup row is electrically connected in series to one pickup in another pickup row except for a signal line for supplying a code. An angle detecting device according to claim 16, wherein: Thus, if any one of the pickups has an abnormality, it has an operation of detecting an abnormality by rotating an angle corresponding to a cycle with the shortest sign change.

The invention according to claim 18 is the angle detecting device according to claim 10, wherein an optical element is used for the pickup. This has the effect of detecting the code pattern and detecting the rotation angle in a non-contact manner, thereby improving the durability.

According to a nineteenth aspect of the present invention, there is provided an automobile using the angle detecting device according to any one of the tenth to twelfth aspects as a steering angle detecting device. This has the effect of detecting the steering angle of the automobile with high resolution, and can realize a small device.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a diagram showing a configuration of an absolute type angle detecting device according to the present invention.

In FIG. 1, the upper case 14 and the lower case 16
Between the pickup fixing portion 19, the multi-rotation detecting disk 18, the one-rotation detecting disk 17, and the reduction gear group 15.
a to 15d, and a multi-rotation detection disk 1
Numeral 8 is connected by a group of reduction gears 15a to 15d so as to be able to rotate at a certain reduction ratio with respect to the disk 17 for one rotation detection. In the present embodiment, the reduction ratio is set to 1/8. That is, the multi-rotation detection disk 18 makes 1/8 rotation with respect to one rotation of the single rotation detection disk 17. The one-rotation detecting disk 17 is configured to rotate in conjunction with an object to be measured (not shown). Specifically, for example, there is a configuration in which the rotation axis of the one-rotation detecting disk 17 and the rotation axis of the object to be measured are the same. A configuration for transmitting rotation is also conceivable. With such a configuration, the rotation angle of the object to be measured can be detected by detecting the rotation angle of the disk 17 for one rotation detection.
An example of the object to be measured is a steering wheel of an automobile. The pickup fixing portion 19 is provided so as to sandwich the single-rotation detecting disk 17 and the multi-rotation detecting disk 18. A microcontroller 20 is provided inside the pickup fixing section 19. A detailed description of the microcontroller 20 will be given later.

As an order of the description, first, the configuration and operation of the single rotation detecting disk 17 will be described, then the configuration and operation of the multi-rotation detecting disk 18 will be described, and finally, an absolute type angle detecting device composed of the two. Will be described.

First, the configuration and operation of the one-turn detection disk 17 will be described.

FIG. 2 is a diagram showing the positional relationship between the pickup and the disk. The one-rotation detecting disk 17 is provided with three concentric rows of code patterns each composed of a combination of slits. From the inside, a second row of code patterns, then a first row of code patterns, and a third row of code patterns at the outermost periphery are provided. The first row of code patterns is formed with the presence or absence of a slit at a 10 ° cycle, the second row of code patterns is a 60 ° cycle, and the third row is 3
Each is formed at a 60 ° cycle. Pickup 1
4 are provided on the pickup fixing portion 19, and the first
At the position facing the code pattern of the row,
They are arranged on the same circumference with a phase shift of 5 ° to form a pickup row. In order to shift the phase by 1.25 °, the pickups may be arranged at intervals of 1.25 °. However, at this interval, the pickup does not fit into a small-diameter disk. They are arranged at 25 ° intervals. Similarly, pickups 5 to 7 are arranged as pickup rows on the same circumference at 10 ° intervals at positions opposed to the second row of code patterns, and 60 ° at positions opposed to the third row of code patterns. At intervals, the pickups 8 to 10 are arranged as pickup rows on the same circumference.

Here, the pickups 1 to 10 use optical elements to detect the presence or absence of a slit provided in the one-turn detection disk 17 to generate a code. The method of detecting the presence or absence of a slit using an optical element is a technique that has already been widely used and will not be described in detail here. Configuration of the transmission system arranged in
There is a reflection type configuration in which the rotation detecting disk 17 is made into a mirror surface and a light emitting element and a light receiving element are arranged in a pair on one side of the single rotation detecting disk 17. In the present invention, a transmissive system using a light emitting element (LED) and a light receiving element (phototransistor) is used, but the present invention can also be implemented using a reflective system.

In the present embodiment, when there is a slit in the disk 17 for one rotation detection, the code generated from the pickup is represented by a binary number "1", and when there is no slit, it is represented by a binary number "0". The code of “1” or “0” generated from one pickup is called “single code”.

The single code from the pickup 1 is the first bit, the single code from the pickup 2 is the second bit, the single code from the pickup 3 is the third bit, and the single code from the pickup 4 is the fourth bit. Handle them together. In this manner, a binary number generated by combining single codes generated from one pickup row into one is referred to as a “code”. The code obtained from the code pattern in the first column in FIG. 2 is referred to as a “first digit code”.

Similarly, the single code from the pickup 5 is changed to 5
The bit, the single code from the pickup 6 is the sixth bit,
The single code from the pickup 7 is used as the seventh bit number,
The 5-bit to 7-bit numbers are collectively handled as a binary number, and a code obtained from the code pattern in the second column is referred to as a “second digit code”.

The same applies to the pickups 8 to 10, and the code obtained from the code pattern in the third column is called the "code of the third digit".

Here, a number in which codes from the third digit to the first digit are arranged in order, that is, a binary number in which numerals from the 10th bit to the 1st bit are arranged in order is called an "angle code".

FIGS. 3 to 9 show the one-turn detection disk 17.
It is a figure which shows the code | symbol which the said pick-up 1-10 supplies in cooperation with FIG. FIG. 3 shows an angle of 1.25 ° to 50 °, FIG.
51.25 ° -100 °, FIG. 5 shows 101.25 ° -1
50 °, FIG. 6 shows 151.25 ° to 200 °, and FIG.
1.25 ° to 250 °, FIG. 8 shows 251.25 ° to 300
9 and FIG. 9 are divided into 301.25 ° to 360 °.

In FIGS. 3 to 9, the uppermost row represents the code of the first digit, and indicates the first to fourth bits in order from the top. Below that, the second digit code is shown, and similarly, the fifth to seventh bits from the top are shown. Below that, the code of the third digit is shown, and the eighth to tenth bits from the top are shown. The column of “resolution” in the figure indicates the number of the position counted when the resolution is 1.25 ° with reference to 0 °. The column of “angle” indicates the angle of the disk 17 for one rotation detection.
The column of “binary number” is a value obtained by converting the number from the 10th bit to the first bit into a binary number, that is, a value obtained by converting the angle code into a decimal number.

In the first digit, eight patterns of gray code codes are supplied, and the codes change every 1.25 °.
The period is 10 °. In the second digit, six gray code codes are supplied, and the code changes every 10 °.
The period is 60 °. In the third digit, six patterns of gray code codes are supplied. The codes change every 60 °, and the period is 360 °. As a result, 288 different codes can be supplied in one rotation, and a resolution of 1.25 ° is realized.

Codes from the first digit to the third digit are supplied as angle codes to a microcontroller 20 disposed in the pickup fixing unit 19, and are converted into rotation angles.
Here, the microcontroller 20 has a table that uniquely defines the angle code and the rotation angle shown in FIGS. 3 to 9, and is also a conversion unit that performs an operation of converting the input angle code into a rotation angle. For example, the code of the third digit is 000, the code of the second digit is 110, and the code of the first digit is 11
In the case of 00, when 0001101100, which is an angle code obtained by connecting these three binary numbers in order from the third digit, is supplied to the microcontroller 20, a rotation angle of 23.75 ° is obtained from the tables shown in FIGS.

As described above, three rows of code patterns and 10
Using a set of pickups, resolution 1. over 360 °.
The rotation angle can be detected at 25 °.

In the present embodiment, as can be seen from FIGS. 3 to 9, there is an angle at which both the change in the sign of the first digit and the change of the sign of the second digit occur. For example, from 10 ° to 1
It is time to change to 1.25 °. The first digit, the second
There is also an angle at which the sign of the digit and the sign of the third digit both change. For example, when changing from 60 ° to 61.25 °. These do not satisfy the gray code property that a plurality of codes do not change at the same time.
Therefore, the angle code is not a gray code.

Originally, the reason why the code of each digit was changed to the gray code was that the slight change in the timing of the code change due to the variation in the mounting position of the pickup and the variation in the dimension of the slit was taken into consideration. In order not to receive it. Therefore, in the method of detecting a rotation angle using an angle code other than the gray code, accurate angle detection may not be performed due to these effects. In the present embodiment, this problem is solved by performing a specific process for an angle at which the sign of each digit, which is a gray code, changes simultaneously.

FIG. 14 shows this procedure. FIG. 13 is a part of the table shown in FIG. 4. The procedure shown in FIG. 14 will be described by taking the part shown in FIG. 13 as an example.

FIG. 13 shows a sequence of codes from the 41st to the 55th in terms of resolution and from 51.25 ° to 68.75 ° in angle conversion. 13 is the same as FIGS.

In FIG. 13, at the judgment point A, the change of the sign of the first digit is accompanied by the change of the sign of the second digit and the change of the sign of the third digit. As described above, when the change in the digit involves a change in the sign of the upper digit, the change in the sign in the digit is referred to as “designated change”. FIG.
, When the first digit changes between 0001 and 0000, and when the second digit changes between 001 and 000, respectively, are designated changes.

Here, the upper digit means a digit whose code change cycle is next longer than that of the lower digit.

In the processing of the procedure of FIG. 14, it is possible to distinguish between when the sign changes beyond the decision point A in FIG. 13 and when it does not.

First, a case where the sign changes from the 44th to the 45th resolution will be described as an example. Resolution No. 44
In the second position, 1110 has already been input to the first digit, 001 has been input to the second digit, and 000 has been input to the third digit, and the microcontroller 20 has obtained a rotation angle of 55 °. This angle code 000
0011110 is a first register (not shown) and a second register.
(Not shown). When the DUT rotates to the 45th resolution, the first 100
The first digit is 1111, the second digit is 001, and the third digit is 000.
Is input to the register. Next, in step 110, the signs stored in the first register and the second register are compared by comparing means (not shown). Since the sign of the first digit has changed, the process proceeds to step 120. Since the change from 1110 to 1111 of the first digit is not a designated change, the process proceeds to step 121. In step 121, the first digit code is changed to 1110
, The angle code of the second register is made the same as the angle code of the first register by the updating means in order to update the angle code from the first register to the new value 1111. As a result, the angle code 0000
011111 (converted to decimal 31) is supplied to the microcontroller 20 to obtain an angle of 56.25 °.

Next, the case where the sign changes to the 48th and 49th resolutions, which is the case where the sign changes beyond the determination point A, will be described. In the 48th resolution, 0001 is obtained in the first digit, 001 is obtained in the second digit, and 000 is obtained in the third digit. When the DUT rotates to the 49th resolution, the first digit is 0000, The second digit is 000,
The third digit is input to the first register as an angle code of 100. When the first register is compared with the second register in step 110, the first digit has changed from 0001 to 0000, so the process proceeds to step 120. Since this change is a designated change, the process proceeds from step 120 to step 130. Step 130
Then, the second digit is checked for a change. Here, the second digit is 0.
Since it has changed from 01 to 000, the procedure proceeds to step 140. In step 140, it is checked whether or not the change in the second digit is a designated change. Since the change in the second digit from 001 to 000 is a designated change, the process proceeds to step 150. In step 150, the third
It is checked whether or not the digit has changed. Since the third digit has also changed from 000 to 001, the process proceeds to step 160. In step 160, the first digit stored so far in the second register is 000
In place of the angle code in which the first and second digits are 001 and the third digit is 000, the newly input angle code is updated to the newly entered angle code of 0000 in the first digit, 000 in the second digit, and 100 in the third digit. do. In step 170, an angle code of 1000000000000 (converted to a decimal number) obtained from the updated value is supplied to the microcontroller 20, and a rotation angle of 61.25 ° is obtained therefrom.

When the sign of the first digit, the second digit, and the third digit change at the same timing when the resolution changes from the 48th to the 49th, the arrangement becomes as described above. Also, it may change at a different timing depending on the dimensional accuracy of the slit. Also in that case, the processing is performed according to the procedure of FIG.

First, the case where the sign changes at a timing where the upper digit is later than the lower digit will be described. Here, a case where the sign of the second digit changes at a timing later than the change of the sign of the first digit, and the sign of the third digit changes at a later timing will be taken as an example.

First, at the 48th resolution, the first digit 000
1, the second digit 001 and the third digit 000 are obtained. If the DUT rotates and the sign of only the first column changes to 0000, the first digit 0000, the second digit 001,
The third digit 000 is entered. The first digit is from 0001 to 00
00, and this change is a designated change.
The process proceeds to step 130 via steps 10 and 120. Here, since the second digit remains unchanged at 001, the processing at this timing ends. At this time, the angle code is not updated,
Resolution First digit 0001, second digit 00 of 48th code
1, the third digit remains 000. If the DUT further rotates and the sign of the second digit changes, the procedure 1
00 gives the first digit 0000, the second digit 000, and the third digit 000. Since the first digit changes from 0001, which is the designated change, to 0000, the process proceeds to step 130 through steps 110 and 120. Since the second digit has been changed from 001 to 000, the process proceeds to step 150 via step 130 and step 140. Since the third digit has not changed yet, the process proceeds from step 150 to the end. Also in this case, the angle code is not updated, and the first digit 0001, the second digit 001, and the third digit 000 of the 48th resolution code remain unchanged.
Further, when the object to be measured rotates and the sign of the third digit changes, the same processing as when the sign of each digit changes at the same timing from the 48th to the 49th resolution is performed, and the angle 61. 25 ° is obtained.

Next, consider the case where the sign changes at a timing where the lower digit is later than the upper digit.

First, at the 48th resolution, the first digit 000
1, the second digit 001 and the third digit 000 are obtained. If the device under test rotates and only the sign of the third digit changes to 100, the first digit 0001, the second digit 001,
The third digit 100 is entered. Next, in step 110, the presence or absence of a change in the sign of the first digit is checked, but since there is no change, the process proceeds to the end and the process at this timing ends. At this time, the sign of each digit is not updated, and the first digit 0001, second digit 001,
It remains at digit 000. If the DUT is further rotated and the second digit is changed, the first digit 00
01, the second digit 000, and the third digit 100 are input. Next, in step 110, the presence or absence of a change in the sign of the first digit is checked, but since there is no change, the process proceeds to the end. Also at this time, the sign of each digit is not updated, and the first code which is the 48th resolution angle code is used.
The digit 0001, the second digit 001, and the third digit 000 remain. When the DUT is further rotated and the first digit is changed, the same processing as when the sign of each digit is changed at the same timing from the 48th to the 49th resolution is performed, and the angle is 61.25. ° is obtained.

As described above, even when the sign changes at a timing where the upper digit lags behind the lower digit, even when the sign changes at a timing where the lower digit lags behind the upper digit. It can be seen that accurate angle detection is performed by the procedure shown in FIG. In addition, this resolution 48
In the case where the sign changes from the 49th to the 49th, the sign of the second digit changes first, and then the sign changes in the order of the first digit and then the third digit. Considering the combination of the case where the sign changes at a timing where the digit is delayed from the lower digit and the case where the sign changes at a timing where the lower digit is delayed from the upper digit, the procedure shown in FIG. It can be easily understood that the detection of a proper angle is performed.

As described above, this is an angle at which the sign of each digit, which is a gray code, changes at the same time, and the sign of each digit is actually changed at a different timing due to the accuracy of parts and the like. Also, accurate angle detection can be performed by the procedure shown in FIG. In other words, if the change in the sign of the lower digit is a designated change and the sign of the upper digit does not change, the sign of each digit is not updated. If the change of the sign of the lower digit is not the designated change, the sign of each digit can be updated as it is.

It should be noted that there is no problem even if the object to be measured is rotated to the vicinity of the angle at which the designated change occurs, and then rotated in reverse. For example, from the 48th resolution to the 4th resolution
Rotate the device under test to the ninth position,
The sign of the digit is changed but the sign of the third digit is not changed, and then rotated in the opposite direction.
It is conceivable that the digits, the second digits, and the third digits all return to the 48th resolution code, but it is clear that accurate angle detection can also be performed for these by performing the processing shown in FIG. It is.

As described above, an accurate angle can be determined based on the change in the sign of the first digit having the shortest change period of the sign.

In the procedure 121 of FIG.
Although "digit update" is described, this is not limited to meaning that only a portion corresponding to the sign of the first digit of the second register is physically updated. The sign of the first digit that has changed means that the value is changed. Therefore, the method of setting the second digit code and the third digit code of the second register as they are, and changing only the first digit code of the second register to the first code of the first register, Also,
Further, a method may be used in which all the signs of the first, second, and third digits of the second register are set to the signs of the first register. Even in the latter case, there is no change in the value of the sign of the second and third digits, and as a result, the value of the second register is the same. The same applies to the procedure 141 in FIG.

Further, as shown in FIG. 2, the code pattern of the third column for supplying the code of the upper digit is arranged on the outer periphery of the disk 17 to increase the strength of the disk 17. This is because the slits are formed continuously in the code pattern for supplying the upper digit having a long period, and the strength at that location is reduced.

FIG. 11 is a diagram showing a disconnection detecting circuit when an optical element is used as a pickup for supplying a code in cooperation with the disk 17 for detecting one rotation. L for the light emitting element
An ED is used, and a phototransistor is used as a light receiving element.

Here, the light emitting elements of the pickup 1 in the first row, the pickup 5 in the second row, and the pickup 8 in the third row are electrically connected in series. By this, one of these
When one light emitting element is disconnected, 10
Within 1 °, an abnormality occurs in the first digit code shown in FIGS. 3 to 9 and disconnection of the pickup can be detected. That is, when a disconnection occurs in any of the light emitting elements of FIG. 11, since these are connected in series, no current flows to any of the light emitting elements. Therefore, the outputs 1, 5 and 8 are always at the H level irrespective of the rotation angle of the one-turn detection disk 17. Here, the output relating to the pickups 1 to 10 is H
Since the sign is “0” at the level and “1” at the L level, the single sign of the pickups 1, 5, and 8 is always 0. At this time, for example, the first digit code that is originally 0011 becomes 0010 due to disconnection, but such a code is a code that is not originally set. Therefore, when the device under test is rotated by 10 °, which is the cycle of the change of the first digit code, such an abnormal code appears, so that disconnection at the pickup can be detected.

Since there are three other pickups in the code pattern in the first row, similarly, the pickups in the second and third rows are electrically connected in series to form all the pickup elements used. Disconnection can be detected.

In this embodiment, an optical element is used for the pickup, but it is also possible to use an element other than the optical element.

With the above configuration, a rotation angle of the object to be measured within 360 ° can be detected, and one rotation angle detecting means can be provided.

Next, the configuration and operation of the multi-rotation detecting disk 18 will be described. In FIG. 2, the pickup 11 is installed so as to face the fourth row of code patterns of the multi-rotation detection disk 18, and the pickups 12 and 13 also face the fifth row of code patterns of the multi-rotation detection disk 18. It is installed to be. The pickups 11 to 13 are provided in the pickup fixing section 19 similarly to the pickups 1 to 10. The same applies to the use of an optical element.

The code pattern in the fourth column has a period of 160 °, and the code pattern in the fifth column is a portion formed in a period of 320 °. The multi-rotation detection disk 18 has a 360-degree circumference, and the fourth and fifth rows of code patterns are formed within a range of 280 degrees. In FIG. 2, assuming that the upper part (at 12 o'clock on the clock face) is 0 °, ± 140 ° corresponds to the fourth row and the fifth row.
The range of the code pattern for the column.

FIG. 10 is a diagram showing symbols detected by the pickups 11 to 13 in cooperation with the multi-rotation detection disk 18. Here, the “rotation angle” in FIG. 10 is represented by the rotation angle of the disk 17 for one rotation detection. Also "binary"
Is obtained by arranging the signs of “0” or “1” of the pickups 11 to 13 as a binary number, and converting this into a decimal number. The binary number at this time is such that the sign of the pickup 13 is the third bit number, the sign of the pickup 12 is the second bit, and the sign of the pickup 11 is the first bit.

Seven patterns of gray code codes are supplied by the pickup 11 facing the fourth row of code patterns and the pickups 12 and 13 facing the fifth row of code patterns on the multi-rotation detection disk 18.
The code obtained in this manner is the multi-rotation detection disk 18.
Has a resolution of 40 ° when represented by the rotation angle of, and a resolution of 320 ° when represented by the rotation angle of the disk 17 for one rotation detection.

The multi-rotation detecting disk 18 is 360 °
It is configured to rotate only 280 ° instead of rotating. This is about 6.2 rotations when converted to the number of rotations of the disk for one rotation detection because the reduction ratio is 1/8.

FIG. 12 is a diagram showing a disconnection detecting circuit when an optical element is used as a pickup for supplying a code in cooperation with the multi-rotation detecting disk 18. The configuration is almost the same as that of FIG. However, when the output is L, the sign is “0”,
When the output is H, the sign is "1", which is opposite to the pickups 1 to 10 shown in FIG.

As shown in FIG. 12, the light emitting elements of the pickups 11 in the fourth row and the pickups 12 and 13 in the fifth row are electrically connected in series. The sign is 1. In contrast, FIG.
As shown in FIG.
Is not set, so that an abnormality at the time of disconnection can be detected.

In this embodiment, the pickups 11 to 1 are set to “1” when the output is L and “0” when the output is H.
A configuration in which a pattern in which all the signs of 3 are “0” may not be set may be adopted. In addition, it is also possible to use a pickup other than an optical element.

With the above configuration, a rotation angle of the object to be measured exceeding 360 ° can be detected, and a multi-rotation angle detection means can be provided.

Next, an absolute type angle detecting device using the single rotation detecting disk 17 and the multi-rotation detecting disk 18 will be described. Unless otherwise noted,
The angle is represented by a numerical value converted to the disk 17 for one rotation detection.

As described above, the disk 1 for one rotation detection
7 and the pickups 1 to 10 can accurately detect the rotation angle within 360 °. Also, 360
For rotations exceeding 0 °, the multi-turn detection disk 18
Can detect the rotation angle, and the resolution is 320 ° smaller than 360 °. Therefore, by combining the two, it is possible to accurately detect a rotation angle exceeding 360 °.

That is, the codes supplied from the pickups 1 to 13 are represented as binary numbers each having a value of the 1st to 13th bits, and the relation between the binary number and the rotation angle of the object to be measured is set as a table by the microcontroller. 20. Thereby, about 6.about.
The angle for two rotations can be detected with a resolution of 1.25 °.

The above-described absolute type angle detecting device can be used as a steering angle sensor of an automobile. That is, the one-turn detection disk 17 is linked to the rotation of the steering of the automobile. As a result, the steering rotation angle of the automobile can be detected, so that it can be used as a steering angle sensor. It should be noted that, as in the present embodiment, it is possible to detect an angle of about 6.2 rotations with a resolution of 1.25 °, which is sufficient as a steering angle sensor for an automobile. Also, as in the present embodiment, the non-contact optical element is used for the pickup, so there is no wear,
Since no trouble such as defective contact does not occur, it is suitable as a steering angle sensor for an automobile.

(Embodiment 2) A conventional absolute-type angle detection device using an n-bit gray code is configured with n columns of code patterns. On the other hand, in the present embodiment, the code patterns of the n-th bit and the (n-1) -th bit are shared as shown in FIGS. This makes it possible to obtain an absolute-type angle detection device using an n-bit gray code with a code pattern of n-1 columns.

FIG. 16 shows the code pattern and the position of the pickup in this embodiment.
5 shows a signal obtained by this.

Conventionally, an absolute-type angle detecting device for supplying 2 n gray codes has, for example, a 3-bit configuration in which the pickup 4 is not provided and only the pickups 1 to 3 are provided in FIG. is there. here,
The code pattern in each column has the following relationship with the other columns. The period of the code pattern in the i-th column is twice the period of the code pattern in the (i-1) -th column, and the phase of the code pattern in the i-th column is i-1
The column is shifted by 1/4 period. As a result, FIG.
In 5, the code of the first to third bits is obtained.

In this embodiment, two pickups are provided in the (n-1) -th row, which is the top of the conventional standard gray code,
The phase difference between the two pickups is shifted by 1/4 of the period of the code pattern in the (n-1) th column.

As a result, as shown in FIG.
It is possible to obtain the code of the number of gray codes.

Here, FIGS. 15 and 16 show n = 4 as an example for explanation, but it is obvious that the same configuration can be made if n is 2 or more.

The multi-rotation detecting disk 18 shown in FIG. 2 of the first embodiment of the present invention uses this principle, and three pickups are arranged for two rows of pattern codes. A bit gray code can be obtained.

[0088]

As described above, in the angle detecting device of the present invention, since the rotation angle is uniquely determined by the code supplied from the pickup, the rotation angle can be detected immediately even in the initial state. In addition, by combining a disc for single rotation detection which detects an angle of the object to be measured within 360 ° with a disc for multi-rotation detection capable of detecting a rotation angle exceeding 360 °, a wide range of rotation angles with high resolution can be obtained. Detection becomes possible. Further, by using a gray code for angle detection and performing a process unique to the present invention when a gray code is not obtained, accurate angle detection can be performed even if the phase of a signal for detecting a rotation angle is shifted. In addition, by using the connection unique to the present invention for the electrical connection of the pickup, it is possible to detect abnormality of the pickup with a simple configuration. And
An optical element can be used for the pickup, and high durability and high reliability can be obtained.

While obtaining the above effects, the present invention makes the arrangement of the pickup unique to the present invention. Therefore, it is not necessary to arrange the pickup over 360 ° outside the disk, and it is easy to reduce the size of the entire apparatus. Can be done.

Also, an automobile using the above angle detecting device as a steering angle sensor can detect the steering rotation angle with high accuracy by the above effect. In addition, a steering angle sensor with few failures can be obtained, and even if a failure such as an abnormality of the pickup occurs, it can be detected promptly, and further safety can be ensured. Further, the size and weight of the vehicle body can be reduced, which is effective in improving fuel efficiency.

[Brief description of the drawings]

FIG. 1 is an assembled perspective view of an angle detection device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a positional relationship between a pickup and a disk according to the first embodiment.

FIG. 3 is a partial arrangement diagram of codes supplied by a one-turn detection disk according to the first embodiment.

FIG. 4 is a partial arrangement diagram of codes supplied by a one-turn detection disk according to the first embodiment.

FIG. 5 is a partial arrangement diagram of codes supplied by a one-turn detection disk according to the first embodiment.

FIG. 6 is a partial arrangement diagram of codes supplied by a one-turn detection disk according to the first embodiment.

FIG. 7 is a partial arrangement diagram of codes supplied by the one-turn detection disk according to the first embodiment.

FIG. 8 is a partial arrangement diagram of codes supplied by the one-turn detection disk according to the first embodiment.

FIG. 9 is a partial arrangement diagram of codes supplied by the one-turn detection disk according to the first embodiment.

FIG. 10 is a code arrangement diagram supplied by the multi-rotation detection disk according to the first embodiment.

FIG. 11 is a circuit diagram of a disconnection detection circuit of the one-rotation detection pickup according to the first embodiment of the present invention.

FIG. 12 is a circuit diagram of a disconnection detection circuit of the multi-rotation detection pickup according to the first embodiment of the present invention.

FIG. 13 is a partially enlarged view of FIG. 4;

FIG. 14 is a diagram showing a control procedure according to the first embodiment of the present invention.

FIG. 15 is a code arrangement diagram according to the second embodiment of the present invention.

FIG. 16 is a relationship diagram between a pickup and a code pattern according to the second embodiment of the present invention.

[Explanation of symbols]

 1-13 Pickup 14 Upper case 15 Reduction gear 16 Lower case 17 1 rotation detection disk 18 Multi rotation detection disk 19 Pickup fixing unit 20 Microcontroller

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01B 11/26 G01B 11/26 Z G01D 5/36 G01D 5/36 Q (72) Inventor Kiyotaka Uehira Osaka 1006 Omon Kadoma, Fumonma-shi Matsushita Electric Industrial Co., Ltd.F-term (reference) MM04 PP13 PP22 QQ04 2F077 AA01 NN02 NN27 PP19 QQ07 RR03 3D030 DB15 DB19 DB27

Claims (19)

[Claims] 1. A disk rotatable in forward and reverse directions, a code pattern provided on the circumference of the disk, and a code pattern provided on the same circumference of the rotation axis of the disk so as to face the code pattern. A plurality of pickups for reading the code pattern and generating a code for determining the rotation angle of the disk; and a conversion unit for converting the code to the rotation angle of the disk, wherein the code is a gray code. An angle detection device comprising one rotation angle detection means. 2. A disk rotatable in forward and reverse directions, a plurality of rows of code patterns provided on different circumferences of the disk, and a concentric circumference of a rotation center axis of the disk facing the code pattern. A pickup array comprising at least one or more pickups for reading the code pattern having a number of rows equal to the number of rows of the code pattern and generating a code for determining a rotation angle of the disc; An angle detection unit comprising a rotation angle detection unit comprising a conversion unit for converting an angle code uniquely defining a rotation angle of the disk by combining codes supplied from a row into a rotation angle of the disk. apparatus. 3. The angle detection device according to claim 2, wherein each code supplied from each of the pickup arrays is a gray code. 4. In the case where a rotation angle is set such that two or more signs change among codes supplied from the respective pickup arrays, the conversion unit rotates until the two or more signs actually change. The angle detection device according to claim 3, wherein the angle is not updated. 5. When a code having a short cycle of change among the two or more codes is a code of a lower digit, and a code having a longer cycle after the lower digit is a code of an upper digit, the code is updated last. The sign of each digit is compared with the sign of each digit detected, and the change of the sign of the lower digit is a rotation angle set to change the two or more signs, and the change of the sign of the upper digit When there is no, the sign of each digit is not updated, and when there is a change in the sign of the upper digit, at least the sign of the digit that has changed is updated to the detected code, and the change of the sign of the lower digit is 5. The angle detecting device according to claim 4, wherein, when the rotation angle is not the setting at which two or more signs change, at least the sign of the digit where the change has occurred is updated to the detected sign. 6. A code having a shorter change period among the two or more codes is a lower-order code, and a code having a longer change period among the two or more codes is a higher-order code. A first register that stores a code supplied by constantly detecting a code pattern from the pickup; a second register that stores a code of each digit updated last and supplies the code to the conversion unit; Comparing means for comparing the sign of the first register with the sign of the second register; and updating means for inputting the sign of the first register into the second register and updating the sign. When the change of the lower digit by the comparing means is a rotation angle set to change the sign of the two or more signs, and when the sign of the upper digit changes, the sign of the second register is changed by the updating means. Update the upper digit When the sign of the second register does not change, the sign of the second register is not updated. When the change of the lower digit is not the rotation angle set to change the sign of 2 or more by the comparing means, the updating means 5. The angle detection device according to claim 4, wherein a sign of said second register is updated. 7. A disk rotatable in forward and reverse directions, a code pattern provided in n-1 rows on the circumference of the disk, and the disk arranged to face the code pattern and reading the code pattern. And a conversion means for converting the code into a rotation angle of the disk, wherein the code is a multi-rotation angle of 2 n gray codes. An angle detection device comprising detection means. 8. A disk rotatable in forward and reverse directions, code patterns provided in n-1 rows on different circumferences of the disk, and arranged so as to face the code patterns, and reading the code patterns. Generating an n-bit code which is a gray code that determines the rotation angle of the disk.
Pickups, and conversion means for converting the code into a rotation angle of the disk, and detecting a code pattern that supplies a code of a bit that changes in the longest cycle among the n-bit codes. An angle including multi-rotation angle detecting means for supplying two n-th codes, wherein two out of n pickups are used and one remaining pickup is provided for each of the remaining code patterns. Detection device. 9. The multi-rotation angle detecting means, wherein the code of the i-th bit changes in a cycle twice as long as the code of the (i-1) -th bit, and the phase of the code of the (i-1) -th bit is changed. i
The code of the n-th bit is shifted in the same cycle as the code of the (n−1) -th bit, and is shifted by １ ／ cycle of the code of the (−1) -th bit. 9. The angle detecting apparatus according to claim 8, wherein the phase is shifted by 1/4 cycle of the code of the (n-1) -th bit with respect to the phase. 10. The angle detecting device according to claim 1, wherein the multi-rotation angle detecting means which rotates in conjunction with the one rotation angle detecting means and supplies a code which uniquely defines a rotation angle is provided. In addition, an angle detection device that detects a rotation angle by the conversion unit provided in the one-rotation angle detection unit using codes supplied from the one-rotation angle detection unit and the multi-rotation angle detection unit. 11. The multi-rotation angle detecting means includes: a disk rotatable in forward and reverse directions;
A code pattern provided in one line, and a code that is arranged to face the code pattern and reads the code pattern to generate a code that determines a rotation angle of the disk
11. The angle detecting device according to claim 10, wherein the angle detecting device comprises a pickup. 12. The angle detection device according to claim 10, wherein the disks of the multi-rotation angle detection means are connected at a predetermined reduction ratio so as to rotate at a lower speed than the disk of the one rotation angle detection means. apparatus. 13. The angle detecting device according to claim 10, wherein a code pattern having the longest cycle among a plurality of the code patterns is provided on an outermost circumference of the disk. 14. The apparatus according to claim 1, wherein a code not used for determining a rotation angle is supplied to said conversion means when an abnormality occurs in the output of said pickup.
0. The angle detection device according to 0. 15. The pickup is electrically connected in series except for a signal line for supplying a detected code pattern, and uses all 0s or all 1s for codes not used to determine the rotation angle. The angle detection device according to claim 14, wherein 16. When an error occurs in the output of the pickup, the pickup rotates a code not used to determine a rotation angle by an angle corresponding to one cycle of a code pattern having the shortest cycle. 11. The angle detecting device according to claim 10, wherein the angle is supplied at least once. 17. A pickup of an arbitrary pickup row is electrically connected in series to one pickup of another pickup row except for a signal line for supplying a code. An angle detection device as described in the above. 18. The angle detection device according to claim 10, wherein an optical element is used for the pickup. 19. An automobile using the angle detection device according to claim 10 as a steering angle detection device.