JP2004239668A - Rotation angle detection device and rotation angle detection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation angle detection device and a rotation angle detection method capable of reducing the power consumption. <P>SOLUTION: An angle detection part 10 is constituted by using first to fourth optical sensors 6-9. The optical sensors 6-9 output repeatedly in prescribed number of times during one rotation of a steering shaft, a gray code comprising a 4-bit binary code changing periodically following rotation of the steering shaft and set so as not to be overlapped during one period. A microcomputer 11 calculates the rotation angle of the steering shaft based on the repeated number of times of the gray code and the value of the gray code. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotation angle detection device and a rotation angle detection method for detecting a steering angle of a steering wheel in a vehicle, for example.
[0002]
[Prior art]
In recent years, when a vehicle is equipped with a vehicle stability control system such as a VSC (Vehicle Stability Control) system (R) and an ESP (Electronic Stability Program) system (R), or an electronic control suspension system, the system control is performed. Therefore, it is necessary to detect the steering angle of the steering. Therefore, conventionally, in such vehicles, a rotation angle detecting device for detecting a steering angle is incorporated in a steering column.
[0003]
Generally, as a rotation angle detection device, a rotation angle detection device of an absolute angle detection method and a rotation angle detection device of a relative angle detection method are known.
2. Description of the Related Art Conventionally, as shown in Patent Document 1, for example, in a rotation angle detection device of an absolute angle detection method, three optical sensors and one magnetoresistive element are used, and each optical sensor detects an angle during one rotation of a rotating plate. Then, the number of rotations of the rotating plate is detected based on the output voltage from the magnetoresistive element. Specifically, the rotating plate is provided with three slit rows having different patterns in the circumferential direction, and each optical sensor is arranged at a position corresponding to the slit rows. Each optical sensor outputs a code of a total of 3 bits based on the presence or absence of the slits in the slit rows. This code does not overlap during one rotation of the rotating plate. For this reason, the rotation angle detecting device can detect the rotation angle of the rotating plate as an absolute value by recognizing the code.
[0004]
According to such a rotation angle detection device of the absolute angle detection method, since the rotation angle of the rotation plate can be detected by an absolute value, even if the rotation plate is rotated while the function is stopped, the rotation plate is restored when the function is restored. Can be detected. However, such a rotation angle detection device of the absolute angle detection method has a disadvantage that a large number of elements are required for angle detection, and it is difficult to design a pattern of a slit provided on the rotation plate.
[0005]
On the other hand, for example, as shown in Patent Literature 2, in a rotation angle detection device of a relative angle detection method, three optical sensors are used, and each optical sensor detects a rotation angle of a rotating plate and performs fail-safe. It has become. Specifically, the rotating plate is provided with a plurality of slits at equal intervals in the circumferential direction, and when the rotating plate is rotated, each optical sensor outputs an alternating binary code based on the presence or absence of the slits. . Then, the rotation angle detection device is configured to relatively calculate the rotation angle of the rotating plate by adding or subtracting the number of changes of the alternating binary code from each optical sensor to the reference angle data.
[0006]
According to the rotation angle detection device of such a relative angle detection method, the rotation angle of the rotation plate can be detected by using at least two optical sensors, and the pattern of the slit provided on the rotation plate can be simplified. Slit pattern design is also facilitated.
[0007]
[Patent Document 1]
JP-A-2002-98522
[Patent Document 2]
JP-A-2000-46536
[0008]
[Problems to be solved by the invention]
By the way, in the rotation angle detection device of the relative angle detection method, when the rotation plate is rotated in the function stop state, the rotation angle of the rotation plate immediately before the stop of the function and the actual rotation angle of the rotation plate at the time of the function return are changed. Will be different. For this reason, even if the vehicle is in the engine stopped state, the rotation angle detection device must continue to detect the rotation angle of the rotating plate. However, if the rotation angle detection device is operated continuously while the engine of the vehicle is stopped, the power consumption may cause the battery to run down. In other words, a large amount of dark current flows to the rotation angle detection device, which may cause the battery to run down. Therefore, conventionally, in order to reduce the power consumption of the rotation angle detection device when the engine is stopped, the rotation angle detection device is operated intermittently and erroneous detection of the rotation angle of the rotation plate is performed based on the sampled calculation angle. To prevent it.
[0009]
Specifically, the resolution of the rotation angle detection device of the relative angle detection method disclosed in Patent Document 2 is set to 1.5 °, and the output phase difference from the optical sensor is 1.5 °. Therefore, the cycle (sampling cycle) in which the rotation angle detecting device is intermittently operated needs to be set to a time interval shorter than at least the time required until the rotating plate is rotated by 1.5 °. That is, for example, when the permissible maximum rotation speed of the rotating plate is two revolutions per second (= 720 ° / sec), a sampling period of about 1 millisecond or less is required.
[0010]
However, in recent years, the demand for reduction in dark current has become more severe due to the increase in electronic control of vehicles and the increase in on-board electrical components, and the rotation angle detection device has further reduced power consumption when the engine is stopped. Is required.
[0011]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a rotation angle detection device and a rotation angle detection method that can reduce power consumption.
[0012]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is configured using at least four pairs of optical elements, which periodically fluctuates with the rotation of the rotating body and does not overlap within one cycle. Angle detection means for repeatedly outputting a gray code consisting of at least a 4-bit binary code, which is set as described above, a predetermined number of times while the rotator rotates once, and the number of repetitions of the gray code and the value of the gray code. And an angle calculation means for calculating a rotation angle of the rotating body based on the rotation angle.
[0013]
According to a second aspect of the present invention, in the rotation angle detection device according to the first aspect, when the rotation angle detection device is in a non-operating state, the angle calculation unit operates at a preset maximum rotation speed. The point is that the angle detecting means is operated intermittently at least once at the timing of calculating the rotation angle of the rotating body before the gray code is repeatedly output when the rotating body is rotated. I do.
[0014]
According to the third aspect of the present invention, at least four bits of binary elements are constituted by at least four pairs of optical elements, are periodically changed with the rotation of the rotating body, and are set so as not to overlap within one cycle. An angle detecting means for repeatedly outputting a gray code composed of a code a predetermined number of times while the rotator makes one rotation, and calculating a rotation angle of the rotator based on the number of repetitions of the gray code and the value of the gray code A rotation angle detection method in a rotation angle detection device provided with an angle calculation unit, wherein when the rotation angle detection device is in a non-operation state, the rotation body is rotated at a preset maximum rotation speed. The angle detecting means is intermittently moved at least once until the gray code is repeatedly output at the timing of calculating the rotation angle of the rotating body. And summarized in that to.
[0015]
Hereinafter, the “action” of the present invention will be described.
According to the first to third aspects of the present invention, the gray code is repeated once each time the rotating body rotates by a predetermined angle. For this reason, the angle calculation means can calculate how many times the predetermined angle has been repeated by counting how many times the gray code output from the angle detection means has been repeatedly output. Further, the angle calculation means can calculate the rotation angle of the rotating body within the predetermined angle based on the binary code value of the gray code. That is, a rough rotation angle of the rotating body is calculated based on the number of repetitions of the gray code, and a minute rotation angle of the rotating body is calculated based on the binary code value of the gray code. As described above, since the absolute angle is detected based on the binary code value of the gray code while the rotating body is rotated by the predetermined angle, the angle calculating unit determines at least until the rotating body is rotated by the predetermined angle. Does not erroneously detect the rotation angle even if the angle detection for sampling is not performed. Therefore, it is possible to lengthen the period of the angle detection for sampling (sampling period), and to reduce the power consumption of the rotation angle detection device.
[0016]
According to the second aspect of the present invention, when the rotation angle detecting device is not operated, the gray code is repeatedly output even when the rotating body is rotated at the preset maximum rotation speed. During this period, the rotation angle of the rotating body is calculated at least once. For this reason, the angle calculation means can reliably count the number of repetitions of the gray code. Therefore, erroneous detection of the rotation angle is reliably prevented.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which the rotation angle detection device of the present invention is embodied as a steering angle detection device that detects a steering angle of a steering in a vehicle will be described in detail with reference to FIGS.
[0018]
As shown in FIG. 1, a steering angle detection device 1 as a rotation angle detection device is disposed in a steering column (not shown) of a vehicle, and is mounted on a steering shaft S as a rotating body. The steering angle detecting device 1 includes a housing 2 fixed to a structure around a steering shaft S, and a rotating plate 3 is rotatably supported on the housing 2. The rotating plate 3 is fixed so as to be fitted on the steering shaft S, and rotates together with the steering shaft S. That is, when the steering shaft S is rotated, the rotating plate 3 rotates equally with the steering shaft S.
[0019]
In the rotating plate 3, a first slit row 4 configured to form a predetermined pattern by a plurality of slits 4a is provided on a circumference of a predetermined diameter centered on the axis thereof. The first slit row 4 is provided in the vicinity of the outer periphery of the rotating plate 3. In the rotating plate 3, a plurality of slits 5a are arranged on a concentric circumference having a smaller diameter than the circumference of the first slit row 4 so as to form a predetermined pattern. A slit row 5 is provided through. That is, the second slit row 5 is provided inwardly of the first slit row 4.
[0020]
A first optical sensor 6 and a second optical sensor 7 are respectively provided at predetermined positions at locations corresponding to the first slit row 4, and a third optical sensor 8 and a second optical sensor 8 are located at locations corresponding to the second slit row 5. Four optical sensors 9 are provided at predetermined positions, respectively. The first to fourth optical sensors 6 to 9 constitute an angle detecting unit 10 as angle detecting means. The first to fourth optical sensors 6 to 9 are configured by photointerrupters having detection units 6a to 9a each including a light emitting element and a light receiving element which are arranged to face each other with the rotating plate 3 interposed therebetween. That is, in the present embodiment, the angle detection unit 10 includes four pairs of optical sensors 6 to 9. For this reason, the first to fourth optical sensors 6 to 9 respectively determine the binary signals S1 to S4 (see FIG. 3A) based on whether or not the corresponding detectors 6a to 9a are blocked by the rotating plate 3. Shown) is output. Specifically, the first optical sensor 6 outputs a binary signal S1, the second optical sensor 7 outputs a binary signal S2, the third optical sensor 8 outputs a binary signal S3, and the fourth optical sensor 9 Outputs a binary signal S4. That is, the first and second optical sensors 6 and 7 output binary signals S1 and S2 according to the presence or absence of each slit 4a of the first slit row 4, and the third and fourth optical sensors 8 and 9 output the second and fourth optical sensors 8 and 9 respectively. Binary signals S3 and S4 are output according to the presence or absence of each slit 5a of the slit row 5.
[0021]
As shown in FIG. 3A, the pattern of the slits 4a and 5a and the arrangement relationship of the first to fourth optical sensors 6 to 9 are such that a 4-bit binary code composed of binary signals S1 to S4 is , And is set to be a gray code composed of 16 types of code patterns that change with the rotation of the rotating plate 3. As shown in the figure, this gray code is a so-called alternating binary code in which only one of the binary signals changes. In the present embodiment, the gray code is set so as to change each time the rotating plate 3 rotates 1.5 °.
[0022]
Next, an electrical configuration of the steering angle detecting device 1 will be described.
As shown in FIG. 2, the steering angle detection device 1 includes the angle detection unit 10, a microcomputer (microcomputer) 11 as an angle calculation unit, a power supply circuit 12, and an interface unit 13.
[0023]
The microcomputer 11 is constituted by a CPU unit having a CPU, a ROM, a RAM, an A / D converter, and the like (not shown). Output signals from the angle detection unit 10 (the first to fourth optical sensors 6 to 9) are input to the microcomputer 11. A power supply circuit 12 is electrically connected to a power supply input terminal Vin of the microcomputer 11, and the microcomputer 11 is supplied with power from the power supply circuit 12.
[0024]
The power supply circuit 12 is configured by a DC-DC converter that reduces a battery voltage and converts the battery voltage into a drive voltage for the microcomputer 11, and has two input terminals. The battery voltage is input to one of the input terminals via an ignition ON relay (not shown), and the battery voltage is input to the other input terminal without passing through the ignition ON relay. Further, the angle detection unit 10 is electrically connected to the power supply circuit 12 via the transistor Tr1. Specifically, the collector terminal of the transistor Tr1 is connected to the power supply circuit 12, and the emitter terminal is connected to the angle detection unit 10. The base terminal of the transistor Tr1 is connected to the microcomputer 11. Therefore, when a base current is supplied from the microcomputer 11 to the transistor Tr1, the transistor Tr1 is activated, and power is supplied from the power supply circuit 12 to the angle detection unit 10. Therefore, the angle detection unit 10 is controlled by the microcomputer 11 to supply power, and outputs the binary signals S1 to S4 when power is supplied.
[0025]
When the microcomputer 11 receives the binary signals S1 to S4 from the angle detection unit 10, the microcomputer 11 determines the rotation angle of the rotary plate 3 based on a 4-bit code pattern (gray code) composed of the binary signals S1 to S4. calculate.
[0026]
More specifically, the microcomputer 11 first converts a 4-bit code pattern including the binary signals S1 to S4 into a predetermined angle signal. Specifically, as shown in FIG. 3A, for example, when the code pattern of the binary signals S1 to S4 is "0000", the microcomputer 11 converts the binary signal into an angle signal having a value of "1". Further, the microcomputer 11 converts each code pattern into an angle signal having a different value, for example, by converting the code pattern into an angle signal having a value of “9” when the code pattern is “1111”. That is, the microcomputer 11 converts each code pattern into 16 types of angle signals. In the present embodiment, when the angle signal is “1”, as shown by a point P0 in FIG. 3B, the rotating plate 3 is at the reference position (the position where the wheel faces the front in the traveling direction = “0 °”). ). Then, in the present embodiment, when the rotating plate 3 is rotated clockwise, the microcomputer 11 can add the angle signal by “1” and convert it into an angle signal from “1” to “16”. It has become. As described above, in the present embodiment, the code pattern changes every time the rotary plate 3 rotates by 1.5 °. Therefore, during the rotation from “0 °” to “22.5 °”, the code pattern changes. Is rotated by 1.5 °, the angle signal is added or subtracted by “1”. That is, while the rotating plate 3 is rotated from “0 °” to “22.5 °”, the angle signal is incremented by “1” every time the rotating plate 3 is rotated 1.5 ° clockwise. The angle signal is subtracted by “1” each time the angle signal is rotated by 1.5 ° in the counterclockwise direction. Then, as schematically shown in FIG. 3B, the code pattern becomes “0000” again at the position where the rotating plate 3 is rotated to “24 °”. The signal becomes "1". That is, the code pattern of the gray code composed of the binary signals S1 to S4 is shifted so that one cycle is obtained every time the rotating plate 3 rotates by 24 °, and is repeated 15 times while the rotating plate 3 makes one rotation. Output.
[0027]
Then, the microcomputer 11 calculates the rotation angle of the rotating plate 3 based on the value of the angle signal and the cycle number of the angle signal. More specifically, for example, when the value of the angle signal is “9” (point P1) in the area A (the transition of the angle signal is one cycle with respect to the reference position) illustrated in FIG. The rotation angle of the rotating plate 3 is calculated as “12 °” (clockwise). When the value of the angle signal is “9” in the area B (the change of the angle signal is two cycles with respect to the reference position) (point P2), the microcomputer 11 sets the rotation angle of the rotating plate 3 to “36 °” ( Clockwise direction). That is, the microcomputer 11 calculates a rotation area (here, areas A to C) from the reference position based on the number of cycles of the change of the angle signal with respect to the reference position, and within the rotation area, The rotation angle of the rotating plate 3 is obtained as an absolute value on the basis of the value of. In other words, the microcomputer 11 counts the period of the angle signal from the reference position, and relatively calculates the rotation area of the rotating plate 3 based on the counted value. The microcomputer 11 calculates the rotation angle of the rotating plate 3 based on the calculated area and the value of the angle signal. Note that the microcomputer 11 outputs the calculated rotation angle to various vehicle systems (for example, a vehicle stability control system, an electronic control suspension system, and the like) via the interface unit 13.
[0028]
Incidentally, the microcomputer 11 recognizes whether or not a battery voltage is input to the power supply circuit 12 via the ignition ON relay. When a battery voltage is input to the power supply circuit 12 via an ignition ON relay, the microcomputer 11 continuously operates the transistor Tr1. For this reason, the angle detector 10 operates continuously and outputs the binary signals S1 to S4 to the microcomputer 11. Therefore, the microcomputer 11 continuously calculates the rotation angle of the rotating plate 3 based on the binary signals S1 to S4.
[0029]
On the other hand, when the battery voltage is not input to the power supply circuit 12 via the ignition ON relay, that is, when the engine of the vehicle is stopped, the microcomputer 11 intermittently operates the transistor Tr1. ing. Specifically, when the rotating plate 3 is rotated at a preset maximum rotation speed (5 rotations per second in the present embodiment), the microcomputer 11 performs one rotation until the rotation angle of the rotating plate 3 shifts by 12 °. The transistor Tr1 is intermittently operated only at the timing (sampling cycle) at which the angle detection unit 10 is operated. That is, when the engine 3 is stopped, the microcomputer 11 performs one sampling cycle until the code patterns of the binary signals S1 to S4 change by eight kinds when the rotating plate 3 is rotated at the maximum rotation speed. The rotation angle of the rotating plate 3 is calculated.
[0030]
For this reason, when the engine is stopped in a state where the rotating plate 3 is at the position shown at the point P2 (rotation angle = 36 °), and then the steering shaft S and the rotating plate 3 are rotated, even if the maximum rotation speed is increased. , The angle is calculated within the region b1 or the region b2 shown in FIG. Therefore, the microcomputer 11 can reliably recognize whether the rotating plate 3 has been rotated clockwise or counterclockwise from the change in the digital signal value.
[0031]
Note that the sampling cycle for operating the angle detection unit 10 is calculated from the formula “(sampling cycle) <(allowable rotation angle per second) ÷ (maximum rotation angle per second)”. That is, in the present embodiment, “(sampling cycle) <12 ÷ 1800” is changed to “(sampling cycle) <0.0066... Second”, and if the sampling cycle is set to “about 6 milliseconds” Good. Incidentally, in the conventional relative angle detection type rotation angle detection device, when the resolution is set to 1 ° and the maximum rotation speed is set to 5 rotations per second, the sampling period is changed from “(sampling period) <1 ÷ 1800” to “(sampling period). Cycle) <0.0005... Seconds, and the sampling cycle must be set to “about 0.5 millisecond”. Therefore, according to the steering angle detection device 1 of the present embodiment, it is possible to make the sampling cycle about 12 times longer than that of the conventional relative angle detection type rotation angle detection device.
[0032]
Therefore, according to the present embodiment, the following effects can be obtained.
(1) The microcomputer 11 sets the transition of the 4-bit code pattern (gray code) composed of the binary signals S1 to S4 output from the angle detection unit 10 (first to fourth optical sensors 6 to 9) to the reference position. On the other hand, the number of the cycle is counted. Thereby, the microcomputer 11 can calculate how many times the rotating plate 3, that is, the steering shaft S has rotated by a predetermined angle (here, 24 °). Further, the microcomputer 11 calculates an absolute angle within a predetermined angle (24 °) based on the code pattern of the binary signal. That is, a rough rotation angle of the steering shaft S is calculated based on the number of cycles (number of repetitions) of the gray code composed of the binary signals S1 to S4, and a small rotation angle of the steering shaft S is calculated based on the value of the gray code. Is calculated. As described above, since the absolute angle is detected while the steering shaft S is rotated by the predetermined angle (24 °), the microcomputer 11 performs sampling at least until the steering shaft S is rotated by “24 °”. Even if the angle detection is not performed, the rotation angle will not be erroneously detected. Therefore, it is possible to lengthen the cycle (sampling cycle) of the angle detection for sampling in the engine stopped state, and to reduce the power consumption of the steering angle detecting device 1.
[0033]
(2) When the steering angle detecting device 1 is in a non-operating (engine stopped) state, even if the steering shaft S is rotated at a preset maximum rotation speed (5 rotations per second), the steering shaft is not rotated. The rotation angle of the steering shaft S is calculated at least once before S is rotated by 12 °. That is, the rotation angle of the steering shaft S is calculated at least twice before the gray code composed of the binary signals S1 to S4 is repeatedly output. Therefore, the microcomputer 11 can reliably recognize whether the steering shaft S has been rotated clockwise or counterclockwise. Therefore, erroneous detection of the rotation angle of the steering shaft S can be reliably prevented.
[0034]
Note that the embodiment of the present invention may be modified as follows.
In the above-described embodiment, the binary signals S1 to S4 output from the angle detection unit 10 change each time the rotating plate 3 is rotated by 1.5 °, thereby detecting the rotation angle. Is set to 1.5 °. However, the resolution for detecting the rotation angle is not limited to 1.5 °, and may be set to an arbitrary resolution such as 1 ° or 2 °. That is, the binary signals S1 to S4 may be arbitrarily changed so as to be changed every time the rotating plate 3 is rotated by 1 ° or to be changed every time the rotating plate 3 is rotated by 2 °. . In this way, for example, even if the detection resolution is increased, it is possible to achieve an effect of reducing power consumption more than before. If the detection resolution is reduced, the power consumption can be further reduced.
[0035]
In the above-described embodiment, the angle detection unit 10 includes four pairs of optical sensors 6 to 9 and outputs binary signals S1 to S4 each composed of a 4-bit gray code. However, the angle detection unit 10 is not limited to the four pairs of optical sensors 6 to 9 but may be configured by five or more pairs of optical sensors. In this case, since a gray code is formed by a code pattern of 5 bits or more, the types of the code patterns are increased (32 types with 5 bits and 64 types with 6 bits). Therefore, it is possible to increase the rotation angle of the rotating plate 3 with respect to one cycle (one repetition) of the gray code, so that the sampling cycle can be further lengthened. Therefore, power consumption can be further reduced. However, since the structure of the steering angle detecting device 1 becomes complicated when many optical sensors are used, it is more preferable to use four to six pairs of optical sensors.
[0036]
The rotation angle detection device may be used as an application other than the steering angle detection device 1 that detects the rotation angle of the steering wheel, for example, as a rotation angle detection device that detects the rotation angle of the rotation shaft in a machine tool having a rotation shaft. Good. When the microcomputer 11 is used as a rotation angle detection device that detects the rotation angle of a rotating body that rotates only in one direction (for example, clockwise), when the rotation angle detection device is not in operation, the microcomputer 11 The rotation angle of the rotating body may be calculated at a sampling cycle different from that of each of the above embodiments. Specifically, the microcomputer 11 performs one cycle until the code pattern (gray code) including the binary signals S1 to S4 changes by one cycle when the rotating body is rotated at the maximum rotation speed. The rotation angle of the rotating body may be calculated at a sampling cycle. By doing so, the sampling period can be further lengthened, and the power consumption of the rotation angle detecting device can be further reduced.
[0037]
Next, in addition to the technical ideas described in the claims, technical ideas grasped by the above-described embodiments will be listed below.
(1) In the rotation angle detection device according to claim 2, the maximum rotation speed is a speed at which the rotating body rotates five times per second.
[0038]
(2) In the rotation angle detection device according to any one of the first and second aspects and the technical idea (1), the angle detection means includes four types of four bits that sequentially shift with the rotation of the rotating body. The angle calculation means outputs a gray code composed of a code pattern of the following. Also, the angle detecting means may be operated intermittently at the timing of calculating the rotation angle of the rotating body until the gray code changes by eight kinds.
[0039]
(3) In the rotation angle detection device according to any one of claims 1 and 2, and the technical ideas (1) and (2), the rotation angle detection device detects a rotation angle of a steering wheel in a vehicle. To be used as an angle detector.
[0040]
【The invention's effect】
As described above in detail, according to the first to third aspects of the present invention, it is possible to reduce the power consumption of the rotation angle detecting device.
[0041]
According to the invention described in claim 2, erroneous detection of the rotation angle can be reliably prevented.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an embodiment in which the present invention is embodied as a steering angle detection device in a vehicle.
FIG. 2 is a block diagram schematically showing an electrical configuration of the embodiment.
FIG. 3A is a table showing a list of gray codes in the embodiment, and FIG. 3B is an explanatory diagram schematically showing an operation of the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Steering angle detection device as rotation angle detection device, 11-14 ... Optical sensors (first to fourth optical sensors) as angle detection means, 15 ... Microcomputer (microcomputer) as angle calculation means, S ... Rotation Steering shaft as body.

Claims (3)

A gray code composed of at least four bits of optical elements, which periodically fluctuates with the rotation of the rotator and which is set so as not to overlap within one cycle, is composed of a binary code of at least four bits. Angle detecting means for repeatedly outputting a predetermined number of times while the rotating body makes one rotation;
A rotation angle detection unit that calculates a rotation angle of the rotating body based on a number of times the gray code is repeated and a value of the gray code. The angle calculation means is in a non-operation state of the rotation angle detection device, until the gray code is repeatedly output when the rotating body is rotated at a preset maximum rotation speed, The rotation angle detection device according to claim 1, wherein the angle detection unit is operated intermittently at least once at a timing of calculating the rotation angle of the rotating body. A gray code consisting of at least four pairs of optical elements, which periodically fluctuates with the rotation of the rotator and which is set so as not to overlap within one period, is formed by a binary code of at least 4 bits. A rotation angle comprising: angle detection means for repeatedly outputting a predetermined number of times during one rotation of the body; and angle calculation means for calculating the rotation angle of the rotating body based on the number of times the gray code is repeated and the value of the gray code. A rotation angle detection method in a detection device,
In the non-operation state of the rotation angle detection device, at least one rotation of the rotation code is performed until the gray code is repeatedly output when the rotating body is rotated at a preset maximum rotation speed. A rotation angle detection method, wherein the angle detection means is operated intermittently at the timing of calculating the rotation angle of the body.

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