JP5176208B2 - Rotation angle detection method and rotation angle sensor - Google Patents

Description

  The present invention relates to a rotation angle detection method and a rotation angle sensor.

  In recent years, cases of using a non-contact type rotation angle sensor as an alternative to a conventional potentiometer or the like for detecting a rotation angle are increasing. As a typical means for non-contact type rotation angle detection, various magnetic types have been provided, but the means for detecting the rotation angle with high accuracy becomes complicated, and a system or sensor for signal processing. There is a problem that the IC becomes huge. On the other hand, for example, a sine wave is output with the rotation of the rotation angle detection body using the configuration as in Patent Document 1, and the pseudo straight line portion is used for relatively accurate accuracy without using complicated signal processing. Means that can be detected well are widely known. However, these means detect the magnetic field that fluctuates in a sine wave with the rotation of the rotation angle detector such as a magnet, and use the output of the pseudo linear portion of the sine wave output. Since the rotation angle is detected, it is difficult to achieve an accuracy higher than that of the pseudo linear portion of the sine wave.

  In addition, a rotation angle position is detected by rotating a magnetoelectric transducer in a parallel magnetic field generated by a magnetic field generator without rotating the magnetic field generator to obtain a sine wave output (Patent Document 2). reference). This means can also improve the temperature characteristics of the magnetoelectric transducer. However, since this means is required to apply a magnetic field that does not change due to the movement of the detected object to one of the magnetoelectric transducers, the rotational angle sensor IC or the like is fixed, and the rotating magnetic field generated by the rotated angle detector is generated. It cannot be used when detecting. In addition, since the sensor IC or the like usually has at least wiring for supplying power or the like, rotating the rotation angle sensor itself may cause a failure. Further, like the technique described in Patent Document 1, since a pseudo linear portion in the sine wave output is used, there is a problem that the rotation angle range in which the rotation angle can be detected with high accuracy is narrow.

  Further, in the prior art, the output has left the temperature characteristics of the magnet or the magnetoelectric conversion element as it is.

  Furthermore, it has been a difficult task to maintain the overall accuracy of rotation angle detection by correcting solid-state variations in temperature characteristics of magnets or magnetoelectric transducers with a temperature correction circuit.

  As a method for canceling the temperature characteristic of the rotation angle sensor, a method of dividing a signal having a phase difference such as a sine wave signal and a cosine wave signal having the same temperature characteristic and converting the signal into a tangent signal or a cotangent signal is well known. However, the work of converting the tangent signal or the cotangent signal into the angle output has caused the deterioration of the angle detection accuracy or the scale of the circuit or system.

JP 2002-303536 A JP 2003-35504 A

  Conventionally known non-contact rotation angle sensors using magnetoelectric transducers perform complex calculations or improve detection accuracy using correction data prepared in advance in order to improve the accuracy of rotation angle detection. Improvement methods have been proposed. However, in such a method using complicated calculations and lookups, the system or sensor IC becomes complicated, and the system or sensor IC becomes large and expensive.

  In addition, generally known at least two or more magnetoelectric transducers are used, and the magnetic field generated by the rotation detection object is sine wave or cosine wave with rotation. In the method of calculating the rotation angle from the tangent calculation or arc tangent calculation using the configuration applied to the unit, the outputs of two or more magnetoelectric transducers that change at the same ratio with respect to the temperature are obtained. Since the angular position is determined by using this, it is known that the temperature characteristic is improved in principle.

  However, when the rotation angle is to be detected with high accuracy in a narrow angle range, the above-described method for calculating the rotation angle from the tangent calculation or the arc tangent calculation uses the system or sensor IC in advance to obtain the data for performing the arc tangent calculation. It is necessary to have to become complicated.

  On the other hand, when performing angle detection in a narrow angle range, a magnetic field that changes in a sine wave shape or a cosine wave shape with respect to the rotation change generated by the rotated angle detector described above is converted into a magnetoelectric conversion without performing such calculation. There is known a method of detecting by an element, outputting it as a sensor output as it is or after being amplified by an amplifier, and detecting an angle with relatively high accuracy by using a pseudo linear portion of the sine wave.

  However, with this method, only the output of the magnetoelectric conversion element or the output having the temperature characteristic of the magnetic field generated by the rotation angle detector can be obtained.

  Accordingly, a first object of the present invention is to provide a rotation angle detection method that realizes good temperature characteristics and detects a rotation angle with high accuracy using a simple configuration.

  A second object of the present invention is to provide a rotation angle sensor having a simple configuration that realizes good temperature characteristics and detects the rotation angle with high accuracy.

In order to solve such a problem, the invention according to claim 1 is characterized in that the phase of the first magnetoelectric conversion element disposed in the vicinity of the circumference of the rotation angle detector is different from that of the first magnetoelectric conversion element. In the rotation angle detection method for detecting the rotation angle of the rotation angle detector using the second magnetic conversion element arranged at a position shifted by 90 °, the first and second magnetoelectric conversion elements are: The first magnetoelectric transducer having substantially the same output temperature characteristics, the step of detecting an applied magnetic field that varies in a sinusoidal shape generated by the rotation angle detector, and the second magnetoelectric transducer, detecting an applied magnetic field varies the cosine wave generated in the rotation angle detecting member, a step of amplifying an amplification factor of the ratio of the output of said second electric transducer, determined Me pre, first The output of the magnetoelectric transducer and before being amplified A step of calculating a sum of squares with an output of the second magnetoelectric conversion element; a step of dividing an output of the first magnetoelectric conversion element by a square root of the sum of squares; and an output of the first magnetoelectric conversion element And a step of detecting a rotation angle of the rotation angle detector using a pseudo linear portion of a calculation result divided by the square root of the sum of squares.

According to a second aspect of the present invention, the first magnetoelectric transducer disposed near the circumference of the rotation angle detector, and the phase of the first magnetoelectric transducer is shifted by 90 °. Using the second magnetic conversion element and the third magnetoelectric conversion element disposed at the same phase as the first magnetoelectric conversion element or at a position shifted in phase by 180 °. In the rotation angle detection method for detecting a rotation angle of the first to third rotations, the first to third magnetoelectric transducers have substantially the same output temperature characteristics, and the first magnetoelectric transducer is the rotation angle detector. Detecting a magnetic field applied in a sine wave generated by the second magnetoelectric transducer, detecting a magnetic field applied in a cosine wave generated by the rotation angle detector, and the second ratios the output of the magnetoelectric converting element, defined Me pre of Amplifying at an amplification factor; calculating a sum of squares of the output of the first magnetoelectric conversion element and the output of the amplified second magnetoelectric conversion element; and driving the third magnetoelectric conversion element The step of increasing or decreasing the voltage value or the drive current value in inverse proportion to the square root of the sum of squares and the rotation angle of the rotation angle detector are detected using a pseudo linear portion of the output of the third magnetoelectric transducer. And the step of performing.

Further, the invention according to claim 3, in claim 1 or 2, before Ki予 Me-determined ratio, and Oite the angle detection range of the target, the maximum error from the pseudo-linear portion is minimal It is set so that it may become .

The invention according to claim 4, in claim 1 or 2, before Ki予 Me-determined ratio, characterized in that it is in the range of 1.2 to 1.9 times.

According to a fifth aspect of the present invention, the first magnetoelectric transducer disposed near the circumference of the rotation angle detector and the first magnetoelectric transducer is disposed at a position that is 90 ° out of phase. In the rotation angle sensor that detects the rotation angle of the rotation angle detector using the second magnetic conversion element, the first and second magnetoelectric conversion elements have substantially the same output temperature characteristics. The first magnetoelectric conversion element detects an applied magnetic field that fluctuates in a sinusoidal shape generated by the rotation angle detector, and the second magnetoelectric conversion element is a cosine wave generated by the rotation angle detector. detecting an applied magnetic field varies, the output of the second magneto-electric conversion element, and the magnetoelectric transducers output amplifier for amplifying an amplification factor of the ratio determined Me pre, an output of the first magneto-electric conversion element, The sum of squares with the output of the amplified second magnetoelectric transducer A square sum operation unit for calculating, a division operation unit for dividing the output of the first magnetoelectric conversion element by the square root of the square sum, and a pseudo linear portion of the output of the division operation unit. And a rotation angle calculation unit that detects a rotation angle of the detection body.

According to a sixth aspect of the present invention, the first magnetoelectric transducer disposed near the circumference of the rotation angle detector and the first magnetoelectric transducer is disposed at a position that is 90 ° out of phase with the first magnetoelectric transducer. Using the second magnetic conversion element and the third magnetoelectric conversion element disposed at the same phase as the first magnetoelectric conversion element or at a position shifted in phase by 180 °. In the rotation angle sensor for detecting the rotation angle of the rotation angle sensor, the first to third magnetoelectric transducers have substantially the same output temperature characteristics, and the first magnetoelectric transducer is connected to the rotation angle detector. An applied magnetic field that varies in a sinusoidal shape is detected, and the second magnetoelectric transducer detects an applied magnetic field that varies in a cosine wave generated by the rotation angle detector, and the second magnetoelectric transducer magnetoelectric conversion element for amplifying an amplification factor of the ratio of the output was determined Me pre A child output amplifier, a square sum calculator for calculating a sum of squares of the output of the first magnetoelectric transducer and the amplified output of the second magnetoelectric transducer, and a drive voltage value or a drive current value. The rotation angle of the rotated angle detector is detected using the third magnetoelectric transducer that increases or decreases in inverse proportion to the square root of the sum of squares and the pseudo linear portion of the output of the third magnetoelectric transducer. And a rotation angle calculation unit.

Further, the invention according to claim 7, in claim 5 or 6, before Ki予 Me-determined ratio, and Oite the angle detection range of the target, the maximum error from the pseudo-linear portion is minimal It is set so that it may become .

The invention according to claim 8, in claim 5 or 6, before Ki予 Me-determined ratio, characterized in that it is in the range of 1.2 to 1.9 times.

  The invention according to claim 9 is the invention according to any one of claims 5 to 8, wherein the first and second magnetoelectric transducers are placed in close proximity to each other together with other arithmetic circuits on a Si substrate by circuit integration technology. It is characterized by being made.

  According to a tenth aspect of the present invention, in any one of the fifth to ninth aspects, the first and second magnetoelectric transducers are arranged in the vicinity of a circumference of a circular magnetic convergence plate. It is characterized by that.

  According to the present invention, by using magnetoelectric conversion elements having substantially the same output temperature characteristics and performing predetermined calculations on the outputs of these magnetoelectric conversion elements, a complicated and huge system or sensor IC is not used. Thus, it is possible to provide a rotation angle detection method and a rotation angle sensor that realize a good temperature characteristic and detect a rotation angle with high accuracy.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a diagram for explaining a rotation angle detection method according to the first embodiment. A rotated angle detector 3 such as a magnet provided with a rotating shaft 4 rotates in any direction of the rotation direction 5. The rotated angle detector 3 generates a magnetic field that changes in a sine wave shape or a cosine wave shape as it rotates. The first magnetoelectric conversion element 1 and the second magnetic conversion element 2 are arranged near the circumference of the rotation angle detector 3, more precisely, directly below the circumference, and are 90 ° out of phase with each other. Yes. A magnetic field that varies in a sine wave shape is applied to the magnetic sensitive part of the first magnetoelectric conversion element 1, and a magnetic field that varies in a cosine wave shape is applied to the magnetic sensitive part of the second magnetoelectric conversion element 2.

  FIG. 2 is a block configuration diagram for performing an operation on the outputs of the first and second magnetic transducer elements. Although not shown in FIG. 1, the first magnetic conversion element 1 is connected to the square sum calculation unit 9, and the second magnetic conversion element 2 is connected to the magnetoelectric conversion element output amplification unit 8. Details of the calculation will be described later.

FIG. 3 is a diagram showing outputs obtained from the first and second magnetic transducer elements along with the rotation of the rotation angle detector in the configuration of FIG. A sinusoidal output V _x 14 is obtained from one magnetic transducer, and a cosine wave output V _y 15 that is 90 ° out of phase is obtained from the other magnetic transducer. The output V _x 14 and the output V _y 15 are expressed by the following equations.

  In the present embodiment, since the magnetoelectric conversion element manufactured by the same process is used and the output temperature characteristics are uniform, the output temperature coefficient α is substantially the same.

Here, the rotation angle detection method according to the present embodiment will be described. First, when the rotation angle detector 3 rotates, the first magnetoelectric conversion element 1 detects an applied magnetic field that fluctuates in a sine wave shape, and the second magnetoelectric conversion element 2 detects an applied magnetic field that fluctuates in a cosine wave shape. To do. Next, the output V _{y of} the second magnetoelectric conversion element 2 is amplified by the magnetoelectric conversion element output amplifier 8 at an amplification factor of a predetermined ratio with respect to the output V _{x of} the first magnetoelectric conversion element 1. Let the amplified output be V _y '. Next, the sum of squares of the output V _x and the output V _y ′ is calculated by the sum of squares calculation unit 9. Next, the square root calculation unit 10 performs a square root calculation represented by the following equation.

Next, the calculation result is transmitted to the division calculation unit 11, and the output V _{x of the} first magnetoelectric conversion element 1 is divided by r. That is, the calculation of V _out = V _x / r is performed. Next, the output V _out of the division calculation unit 11 is sent to the calculation result amplification unit 12 and amplified, and then output through the calculation result output unit 13. Finally, a rotation angle calculation unit (not shown) calculates a rotation angle using a pseudo linear portion of the calculation result.

FIG. 4 is a diagram showing a calculation result when the amplification factor of a predetermined ratio is 1.3. The pseudo linear portion 16 of the calculation result has a wider range of pseudo linear portions than the sine wave output, and the linearity is improved. Specifically, the maximum error from the approximate straight line is about 0.08 ° in a range of ± 50 ° from the center of the pseudo straight line portion 16, and an improvement in linearity is obtained. In the sine wave output, an error of about 2.5 ° occurs in the ± 50 ° range. In addition, since the first magnetoelectric conversion element 1 and the second magnetoelectric conversion element 2 are manufactured by the same process, the output temperature coefficient α is excluded from the calculation result _Vout , and the calculation result has good temperature characteristics. It becomes. Therefore, it is possible to realize a favorable temperature characteristic using a simple configuration and to detect the rotation angle with high accuracy over a wider range than in the case of using a sine wave output.

In the above description, the output V _y of the second magnetoelectric conversion element 2 is amplified by 1.3 times the output V _{x of} the first magnetoelectric conversion element 1. As a result, the operation result obtained is as shown in the following equation, and it becomes possible to obtain a sine wave output having no temperature dependency.

Although the output V _y of the second magnetoelectric conversion element 2 is amplified, the output V _x of the first magnetoelectric conversion element 1 may be amplified. In this case, the value divided by the division calculation unit 11 is the output V _y .

  Further, the predetermined ratio can be set to 1.2 to 1.9, and the optimum value varies depending on the target rotation angle detection range. FIG. 6 is a diagram illustrating a relationship between a predetermined ratio and an error in an arbitrary angle detection range. As seen in FIG. 6, the optimum ratio varies depending on the range of angles to be measured.

  Each arithmetic unit can be implemented with an analog circuit or a digital circuit.

  Further, the rotation angle can be detected using the configuration shown in FIG. 5 instead of FIG. In the configuration shown in FIG. 5, the first magnetoelectric conversion element 1 and the second magnetoelectric conversion element 2 are arranged in the vicinity of the circumference of a magnetic convergence plate 17 formed in a circle. The magnetic focusing plate 17 is made of a magnetic material, and can convert a horizontal magnetic field component into a vertical magnetic field component with respect to the magnetic sensitive surfaces of the first magnetoelectric conversion element 1 and the second magnetoelectric conversion element 2. . That is, in FIG. 5, a magnetic field parallel to the paper surface at the position of the first magnetoelectric conversion element 1 and the second magnetoelectric conversion element 2 can be converted into a magnetic field perpendicular to the paper surface by the magnetic converging plate 17. it can. Therefore, it is suitable when a Hall element that detects only a magnetic field component perpendicular to the magnetosensitive surface of the first magnetoelectric conversion element 1 and the second magnetoelectric conversion element 2 is selected as the magnetoelectric conversion element. It is also possible to collect the surrounding magnetic flux and amplify the magnetic flux density applied to the magnetosensitive surface of the magnetoelectric transducer.

  Further, the rotation angle detection method and rotation angle sensor according to the present embodiment can be used for detecting an inclination angle of an input device such as a joystick and for detecting an opening / closing angle of a valve valve.

(Embodiment 2)
In the rotation angle detection method according to the second embodiment, the division calculation unit 11 is different from the first embodiment. In the second embodiment, instead of the division calculation unit 11, the third magnetoelectric conversion element manufactured by the same process as the first and second magnetoelectric conversion elements is a division target in the division calculation unit 11 of the first embodiment. It is separately provided at a position that is in phase with the first magnetoelectric conversion element or at a position where an output that is 180 ° out of phase with the first magnetoelectric conversion element can be obtained. By increasing or decreasing the drive voltage value or drive current value of the third magnetoelectric conversion element in inverse proportion to the output r of the square root calculation unit 10 to obtain the output of the third magnetoelectric conversion element, the first to third magnetoelectric elements are obtained. The temperature characteristic of the conversion element can be canceled, and the same effect as in the first embodiment can be obtained.

  It should be noted that various modifications are possible as described in the first embodiment.

It is a figure for demonstrating the rotation angle detection method which concerns on Embodiment 1. FIG. It is a block block diagram for calculating with respect to the output of the 1st and 2nd magnetic conversion element. It is a figure which shows the output obtained from a 1st and 2nd magnetic conversion element with rotation of a to-be-rotated angle detection body in the structure of FIG. It is a figure which shows the calculation result in case the amplification factor of the predetermined ratio in Embodiment 1 is 1.3. It is a figure for demonstrating the deformation | transformation form of Embodiment 1. FIG. It is a figure which shows the relationship between the predetermined ratio and error in Embodiment 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st magnetoelectric conversion element 2 2nd magnetoelectric conversion element 3 Rotation angle detection body 4 Rotating shaft 5 Rotation direction 8 Magnetoelectric conversion element output amplifier 9 Square sum calculation part 10 Square root calculation part 11 Division calculation part 12 Calculation value amplifier DESCRIPTION OF SYMBOLS 13 Calculation result output part 14 Output of 1st magnetoelectric conversion element 15 Output of 2nd magnetoelectric conversion element 16 Pseudo linear part of calculation result 17 Magnetic convergence board

Claims (9)

Using the first magnetoelectric transducer disposed near the circumference of the rotation angle detector, and the second magnetic transducer disposed at a position 90 degrees out of phase with the first magnetoelectric transducer, In the rotation angle detection method for detecting the rotation angle of the rotation angle detector,
The first and second magnetoelectric transducers have substantially the same output temperature characteristics,
The first magnetoelectric transducer detecting an applied magnetic field varying in a sinusoidal shape generated by the rotation angle detector; and
The second magnetoelectric transducer detecting an applied magnetic field that fluctuates in a cosine wave generated by the rotated angle detector;
A method of amplifying an amplification factor of the ratio of the output of said second electric transducer, determined Me pre,
Calculating a sum of squares of the output of the first magnetoelectric transducer and the amplified output of the second magnetoelectric transducer;
Dividing the output of the first magnetoelectric transducer by the square root of the sum of squares;
Detecting a rotation angle of the rotation angle detector using a pseudo linear portion of a calculation result obtained by dividing the output of the first magnetoelectric transducer by the square root of the square sum. Rotation angle detection method. A first magnetoelectric transducer disposed near the circumference of the rotation angle detector; a second magnetic transducer disposed at a position 90 degrees out of phase with the first magnetoelectric transducer; In a rotation angle detection method for detecting a rotation angle of the rotation angle detection body using a first magnetoelectric conversion element and a third magnetoelectric conversion element arranged at the same phase position or at a position shifted in phase by 180 ° ,
The first to third magnetoelectric transducers have substantially the same output temperature characteristics,
The first magnetoelectric transducer detecting an applied magnetic field varying in a sinusoidal shape generated by the rotation angle detector; and
The second magnetoelectric transducer detecting an applied magnetic field that fluctuates in a cosine wave generated by the rotated angle detector;
A method of amplifying an amplification factor of the ratio of the output of said second electric transducer, determined Me pre,
Calculating a sum of squares of the output of the first magnetoelectric transducer and the amplified output of the second magnetoelectric transducer;
Increasing or decreasing the driving voltage value or driving current value of the third magnetoelectric transducer in inverse proportion to the square root of the square sum;
And a step of detecting a rotation angle of the rotation angle detector using a pseudo linear portion of an output of the third magnetoelectric transducer. Ratio defined before Ki予 Me is Oite the angle detection range of the target, according to claim 1 or 2 maximum error from the pseudo-linear portion, characterized in that it is set to minimize Rotation angle detection method. Ratio defined before Ki予 first is the rotation angle detecting method according to claim 1 or 2, characterized in that in the range of 1.2 to 1.9 times. Using the first magnetoelectric transducer disposed near the circumference of the rotation angle detector, and the second magnetic transducer disposed at a position 90 degrees out of phase with the first magnetoelectric transducer, In the rotation angle sensor for detecting the rotation angle of the rotation angle detector,
The first and second magnetoelectric transducers have substantially the same output temperature characteristics,
The first magnetoelectric transducer detects an applied magnetic field that fluctuates in a sine wave generated by the rotated angle detector,
The second magnetoelectric transducer detects an applied magnetic field that fluctuates in a cosine wave generated by the rotated angle detector,
The output of the second magneto-electric conversion element, and the magnetoelectric transducers output amplifier for amplifying an amplification factor of the ratio determined Me pre,
A sum-of-squares calculation unit that calculates the sum of squares of the output of the first magnetoelectric conversion element and the output of the amplified second magnetoelectric conversion element;
A division operation unit for dividing the output of the first magnetoelectric transducer by the square root of the square sum;
A rotation angle sensor comprising: a rotation angle calculation unit that detects a rotation angle of the rotation angle detector using a pseudo linear portion of an output of the division calculation unit. A first magnetoelectric transducer disposed near the circumference of the rotation angle detector; a second magnetic transducer disposed at a position 90 degrees out of phase with the first magnetoelectric transducer; A rotation angle sensor for detecting a rotation angle of the rotation angle detector using a third magnetoelectric conversion element disposed at a position having the same phase as that of one magnetoelectric conversion element or a position shifted in phase by 180 °;
The first to third magnetoelectric transducers have substantially the same output temperature characteristics,
The first magnetoelectric transducer detects an applied magnetic field that fluctuates in a sine wave generated by the rotated angle detector,
The second magnetoelectric transducer detects an applied magnetic field that fluctuates in a cosine wave generated by the rotated angle detector,
The output of the second magneto-electric conversion element, and the magnetoelectric transducers output amplifier for amplifying an amplification factor of the ratio determined Me pre,
A sum-of-squares calculation unit that calculates the sum of squares of the output of the first magnetoelectric conversion element and the output of the amplified second magnetoelectric conversion element;
The third magnetoelectric transducer for increasing or decreasing the drive voltage value or drive current value in inverse proportion to the square root of the square sum;
A rotation angle sensor comprising: a rotation angle calculation unit that detects a rotation angle of the rotation angle detector using a pseudo linear portion of the output of the third magnetoelectric transducer. Ratio defined before Ki予 Me is Oite the angle detection range of the target, according to claim 5 or 6 maximum error is characterized in that it is set to be the minimum from the pseudo-linear portion Rotation angle sensor. The ratio defined before Ki予 Me, the rotation angle sensor according to claim 5 or 6, characterized in that in the range of 1.2 to 1.9 times.   The rotation according to any one of claims 5 to 8, wherein the first and second magnetoelectric transducers are made in close proximity to each other together with other arithmetic circuits on a Si substrate by a circuit integration technique. Angle sensor.

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