JP2024054797A - Rotation angle detection device, rotation angle detection method and rotation angle detection program - Google Patents

Abstract

To provide a rotation angle detection device, a rotation angle detection method and a rotation angle detection program capable of suppressing detection error of a rotation angle even when inputting detection results of two Hall sensors into one arithmetic circuit.SOLUTION: A rotation angle detection device comprises: an acquisition unit that acquires detection results from each of a first detection element that detects a magnetic field of a magnetic field generation unit provided on a detection target that detects a rotation angle and a second detection element that detects a magnetic field arranged at a position having an angular difference of 90 electrical degrees from the first detection element along a rotational direction of the detection target; a setting unit that sets a first digital value based on the acquired detection result of the first detection element, and sets a second digital value based on the acquired detection result of the second detection element, according to the acquisition status of the detection result of the first detection element; and a calculation unit that calculates the rotation angle of the detection target using the set first digital value and second digital value.SELECTED DRAWING: Figure 4

Description

This disclosure relates to a rotation angle detection device, a rotation angle detection method, and a rotation angle detection program that detect the rotation angle of a detection object.

Patent Document 1 discloses a rotation angle detection device that detects and outputs the rotation angle of an object to be detected with high accuracy even if there is a misalignment in the amplitude of the output signal due to variations in the sensitivity adjustment of a Hall element for detecting a magnetic field.

The rotation angle detection device is equipped with a Hall element that detects changes in magnetic flux caused by a magnet installed in a detection target such as a motor, and outputs a signal in the form of a sine wave indicating the detected change in magnetic flux. The rotation angle detection device has two Hall elements arranged at positions that are 90° apart in electrical angle along the rotation direction of the detection target, and reduces detection errors in the rotation angle by matching the amplitudes of the signals detected by the two Hall elements and performing angle calculations using the signals.

JP 2016-145729 A

In the rotation angle detection device disclosed in the above-mentioned Patent Document 1, signals obtained by detecting a magnetic field using two Hall elements are input to one calculation circuit. In the rotation angle detection device, if one Hall element detects a magnetic field and then another Hall element detects a magnetic field, the residual charge in the signal from one Hall element may affect the signal from the other Hall element.

As a result, when signals from two Hall elements are input to a single calculation circuit, detection distortion occurs in the calculation results of the rotation angle of the object to be detected, and it is not always possible to suppress detection errors in the rotation angle.

The present disclosure aims to provide a rotation angle detection device, a rotation angle detection method, and a rotation angle detection program that can suppress rotation angle detection errors even when the detection results from two Hall elements are input to a single calculation circuit.

The rotation angle detection device according to the first aspect of the present disclosure includes an acquisition unit (21A, 21B) that acquires detection results from a first detection element (11) that detects a magnetic field of a magnetic field generating unit (3) provided on a detection target for detecting a rotation angle, and a second detection element (12) that detects the magnetic field and is disposed at a position with an angular difference of 90° electrical angle from the first detection element (11) along the rotation direction of the detection target, a setting unit (22A, 22B) that sets a first digital value based on the acquired detection result of the first detection element (11) and sets a second digital value based on the acquired detection result of the second detection element (12) according to the acquisition status of the detection result of the first detection element (11), and a calculation unit (23) that calculates the rotation angle of the detection target using the set first digital value and the second digital value.

The rotation angle detection device according to the second aspect of the present disclosure is the rotation angle detection device according to the first aspect, in which the acquisition unit acquires the detection result by the first detection element, and then acquires the detection result by the second detection element twice in succession, and the setting unit sets the second digital value based on the later of the two detection results by the second detection element.

The rotation angle detection device according to the third aspect of the present disclosure is the rotation angle detection device according to the second aspect, in which the setting unit corrects and sets the second digital value using a correction value that is predetermined according to the detection result by the first detection element.

The rotation angle detection device according to the fourth aspect of the present invention is the rotation angle detection device according to the third aspect, in which the setting unit corrects the second digital value by adding the correction value to the second digital value.

The rotation angle detection method according to the fifth aspect of the present disclosure executes the following process: acquiring detection results from a first detection element that detects the magnetic field of a magnetic field generating unit provided on a detection target for detecting a rotation angle, and a second detection element that detects the magnetic field and is disposed at a position that has an angular difference of 90° electrical angle from the first detection element along the rotation direction of the detection target; setting a first digital value based on the acquired detection result of the first detection element; setting a second digital value based on the acquired detection result of the second detection element according to the acquisition status of the detection result of the first detection element; and calculating the rotation angle of the detection target using the set first digital value and second digital value.

The rotation angle detection program according to the sixth aspect of the present disclosure causes at least one processor to execute a process of acquiring detection results from a first detection element that detects the magnetic field of a magnetic field generating unit provided on a detection target for detecting a rotation angle, and a second detection element that detects the magnetic field and is disposed at a position that has an angular difference of 90° electrical angle from the first detection element along the rotation direction of the detection target, setting a first digital value based on the acquired detection result of the first detection element, and setting a second digital value based on the acquired detection result of the second detection element according to the acquisition status of the detection result of the first detection element, and calculating the rotation angle of the detection target using the set first digital value and second digital value.

According to the present disclosure, angle detection errors can be suppressed even when the detection results from two Hall elements are input to a single calculation circuit.

3 is a schematic diagram showing an example of a configuration of a detection target according to each embodiment; FIG. 4 is a side view showing an example of a rotating body for explaining the arrangement of Hall elements according to each embodiment. FIG. FIG. 2 is a block diagram showing an example of a hardware configuration of the rotation angle detection device according to each embodiment. 2 is a block diagram showing an example of a functional configuration of the rotation angle detection device according to the first embodiment; FIG. 5 is a flowchart showing an example of a flow of a rotation angle detection process according to the first embodiment. FIG. 11 is a block diagram showing an example of a functional configuration of a rotation angle detection device according to a second embodiment. 10 is a flowchart showing an example of a flow of a rotation angle detection process according to the second embodiment.

[First embodiment]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0023]The present invention will now be described in detail with reference to the accompanying drawings, in which: [0024]FIG. 1 is a schematic diagram showing an example of the configuration of a detection target such as a rotating body according to this embodiment.

As an example, as shown in FIG. 1, a rotating body 1 such as a motor includes a stator 2 and a rotor 4 including multiple pairs of permanent magnets 3. The rotation angle detection device 10 includes a first Hall element 11 and a second Hall element 12. Here, the permanent magnet 3 is an example of a "magnetic field generating unit", and the first Hall element 11 and the second Hall element 12 are examples of a "detection element". In this embodiment, the rotation angle detection device 10 is installed outside the rotating body 1. However, this is not limited to this. The rotation angle detection device 10 may be installed inside the rotating body 1. In addition, the rotating body 1 according to this embodiment is a motor. However, this is not limited to this. The rotating body may be a steering wheel or the like, or any other object that rotates. In addition, the rotating body 1 according to this embodiment is an embodiment including multiple pairs of permanent magnets 3. However, this is not limited to this. The permanent magnets 3 may be a pair.

In the rotating body 1, the stator 2 has a coil 5 wound around it so as to straddle slots (not shown), and a magnetic field is generated by current flowing through the coil 5. The permanent magnet 3 constitutes a magnetic field generating means. For example, the stator 2 is fixed to the rotating body 1 that detects the rotation angle, and the permanent magnet 3 is formed in an arc shape and fixed to the inner peripheral wall of the cylindrical rotor 4. The permanent magnets 3 are arranged so that the north and south poles are alternately positioned, generating a magnetic field that is approximately parallel and has an approximately uniform magnetic flux density. In addition, the rotor 4 rotates together with the permanent magnet 3 in the circumferential direction indicated by the arrow in FIG. 1 due to repulsion between the magnetic field generated by the coil 5 and the magnetic field generated by the permanent magnet 3.

The rotation angle detection device 10 detects the rotation angle of the detection target using signals detected by the first Hall element 11 and the second Hall element 12. The first Hall element 11 and the second Hall element 12 are sensors that detect the magnetic field generated by the permanent magnet 3. The first Hall element 11 and the second Hall element 12 are arranged along the circumferential direction of the rotor 4 with an angular difference of 90° electrical angle from each other, and are fixed to a support member (not shown) so as not to rotate together with the rotation of the rotor 4.

2, the first hall element 11 and the second hall element 12 are disposed inside the rotating body 1 at positions where the magnetic field generated from the permanent magnet 3 can be detected. For example, the first hall element 11 and the second hall element 12 are disposed inside the rotating body 1 at positions where the magnetic field can be detected, axially above the permanent magnet 3, in a range from the radially inner end of the permanent magnet 3 to the radially inner end of the stator 2. The first hall element 11 and the second hall element 12 may be disposed axially above a slot (between one coil 5 and another adjacent coil 5) not shown.

The first Hall element 11 and the second Hall element 12 rotate relative to the permanent magnet 3 which rotates with the rotor 4, and detect a change in the magnetic field caused by the rotation. Here, the first Hall element 11 and the second Hall element 12 are arranged with an angular difference of 90° electrical angle from each other, and therefore the first Hall element 11 and the second Hall element 12 output signals with a phase difference of 90° electrical angle from each other. In this embodiment, a configuration will be described in which the first Hall element 11 detects a SIN signal, and the second Hall element 12 detects a COS signal. However, this is not limiting. The first Hall element 11 may detect a COS signal, and the second Hall element 12 may detect a SIN signal.

Next, the hardware configuration of the rotation angle detection device 10 will be described with reference to FIG. 3. FIG. 3 is a block diagram showing an example of the hardware configuration of the rotation angle detection device according to this embodiment.

As an example, as shown in FIG. 3, the rotation angle detection device 10 includes a first hall element 11, a second hall element 12, a control unit 13, a ROM (Read Only Memory) 14, a RAM (Random Access Memory) 15, a multiplexer 16, and an analog-to-digital conversion circuit (hereinafter referred to as the "AD conversion circuit") 17. The control unit 13, the ROM 14, the RAM 15, and the AD conversion circuit 17 are each connected to each other by a bus 19.

The first hall element 11 and the second hall element 12 are sensors that detect the magnetic field of the permanent magnet 3. The control unit 13 manages and controls the entire rotation angle detection device 10. The ROM 14 stores various programs, data, etc. The RAM 15 is a memory used as a work area when various programs are executed. The control unit 13 loads the programs stored in the ROM 14 into the RAM 15 and executes them to perform processing to detect the rotation angle of the detection target.

The multiplexer 16 is connected to the first hall element 11, the second hall element 12, and the AD conversion circuit 17. The multiplexer 16 switches between and selects the signals input from the first hall element 11 and the second hall element 12, and outputs them to the AD conversion circuit 17. Note that the multiplexer 16 according to this embodiment will be described as selecting the SIN signal detected by the first hall element 11, and then selecting the COS signal detected by the second hall element 12 twice. However, this is not limited to this. The multiplexer 16 may select the SIN signal twice after selecting the COS signal.

The AD conversion circuit 17 converts the analog signals representing the SIN signal and COS signal output by the multiplexer 16 into digital signals.

Next, the functional configuration of the rotation angle detection device 10 will be described with reference to FIG. 4. FIG. 4 is a block diagram showing an example of the functional configuration of the rotation angle detection device 10 according to this embodiment.

As an example, as shown in FIG. 4, the rotation angle detection device 10 includes an acquisition unit 21A, a setting unit 22A, and a calculation unit 23.

The acquisition unit 21A acquires signals of magnetic fields detected from the first hall element 11 and the second hall element 12 via the multiplexer 16. Here, the acquisition unit 21A acquires the signal detected by the first hall element 11 as a SIN signal, and the signal detected by the second hall element 12 as a COS signal. The acquisition unit 21A also acquires the COS signal twice in succession. In the following, of the COS signals acquired twice in succession, the COS signal acquired first is referred to as the "first COS signal," and the COS signal acquired later is referred to as the "second COS signal."

The setting unit 22A sets the values of the digital signals representing the SIN signal and the COS signal as setting values for calculating the rotation angle, and outputs them to the calculation unit 23. Specifically, the setting unit 22A sets the value of the digital signal representing the SIN signal as the setting value related to the SIN signal, and sets the value of the digital signal representing the second COS signal as the setting value related to the COS signal.

The calculation unit 23 uses each of the set values to derive the rotation angle of the detection object. Specifically, the calculation unit 23 uses the set values for the SIN signal and the set values for the COS signal to calculate θ=tan ^-1 (SIN θ/COS θ) to derive the rotation angle of the detection object. Here, θ is the rotation angle of the detection object, and tan ^-1 is the inverse function of tangent. SIN θ is the set value for the SIN signal, and COS θ is the set value for the COS signal.

Next, a method for detecting a rotation angle according to this embodiment will be described with reference to FIG. 5. FIG. 5 is a flowchart showing an example of a method for detecting a rotation angle according to this embodiment.

In step S101, the rotation angle detection device 10 acquires the SIN signal detected by the first Hall element 11.

In step S102, the rotation angle detection device 10 converts the acquired SIN signal into a digital value.

In step S103, the rotation angle detection device 10 sets a digital value related to the converted SIN signal as a SIN signal and outputs it.

In step S104, the rotation angle detection device 10 acquires the first COS signal detected by the second Hall element 12.

In step S105, the rotation angle detection device 10 converts the acquired first COS signal into a digital value.

In step S106, the rotation angle detection device 10 acquires the second COS signal detected by the second Hall element 12.

In step S107, the rotation angle detection device 10 converts the acquired second COS signal into a digital value.

In step S108, the rotation angle detection device 10 sets and outputs a digital value related to the converted second COS signal as a COS signal.

In step S109, the rotation angle detection device 10 uses the SIN signal and the COS signal to derive the rotation angle of the object to be detected.

In step S110, the rotation angle detection device 10 outputs the derived rotation angle.

As described above, according to this embodiment, angle detection errors can be suppressed even when the detection results from two Hall elements are input to a single calculation circuit.

[Second embodiment]
In the first embodiment, a configuration was described in which after acquiring a SIN signal, a rotation angle was calculated using a second COS signal, thereby suppressing detection errors in the rotation angle due to the effect of the SIN signal on the COS signal. In the present embodiment, a configuration will be described in which detection errors in the rotation angle are suppressed by correcting the COS signal.

In the following, the configuration of the rotating body (see FIG. 1), an example of the rotating body (see FIG. 2), and the hardware configuration of the rotation angle detection device 10 (see FIG. 3) are the same as those in the first embodiment, so their explanations will be omitted. In addition, the multiplexer 16 in this embodiment will be described as selecting the SIN signal detected by the first Hall element 11 and the COS signal detected by the second Hall element 12 once each.

The functional configuration of the rotation angle detection device 10 will be described with reference to FIG. 6. FIG. 6 is a block diagram showing an example of the functional configuration of the rotation angle detection device 10 according to this embodiment. Note that in FIG. 6, the same components as those in the rotation angle detection device 10 shown in FIG. 4 are given the same reference numerals as in FIG. 4, and the description thereof will be omitted.

As an example, as shown in FIG. 6, the rotation angle detection device 10 includes an acquisition unit 21B, a setting unit 22B, and a calculation unit 23.

The acquisition unit 21B acquires signals of magnetic fields detected from the first hall element 11 and the second hall element 12 via the multiplexer 16. Here, the acquisition unit 21B acquires the signal detected by the first hall element 11 as a SIN signal, and acquires the signal detected by the second hall element 12 as a COS signal.

The setting unit 22B sets the values of the digital signals representing the SIN signal and the COS signal as setting values for calculating the rotation angle, and outputs them to the calculation unit 23. Specifically, the setting unit 22B sets and outputs a digital value representing the SIN signal as the setting value related to the SIN signal. The setting unit 22B also obtains a correction value that is predetermined according to the value of the SIN signal from the ROM 14, and corrects the digital value of the COS signal using the correction value. The setting unit 22B corrects the digital value representing the COS signal by adding the correction value to it, and sets the digital value representing the corrected COS signal as the setting value related to the COS signal.

Next, a method for detecting a rotation angle according to this embodiment will be described with reference to FIG. 7. FIG. 7 is a flowchart showing an example of a method for detecting a rotation angle according to this embodiment. Note that in FIG. 7, steps that are the same as those in the process for detecting a rotation angle shown in FIG. 5 are given the same reference numerals as in FIG. 5, and descriptions thereof will be omitted.

In step S111, the rotation angle detection device 10 acquires the COS signal detected by the second Hall element 12.

In step S112, the rotation angle detection device 10 converts the acquired COS signal into a digital value.

In step S113, the rotation angle detection device 10 obtains a correction value according to the SIN signal.

In step S114, the rotation angle detection device 10 corrects the COS signal by adding the correction value to the digital value related to the converted COS signal.

As described above, according to this embodiment, as in the first embodiment, angle detection errors can be suppressed even when the detection results from two Hall sensors are input to a single calculation circuit.

In the above embodiment, a form in which the digital value related to the COS signal is corrected using a correction value has been described. However, this is not limiting. For example, in addition to correcting the digital values related to the SIN signal and the COS signal, the amplitudes of the SIN signal and the COS signal may be further corrected using known technology (see, for example, Patent Document 1).

[Patent Document 1] JP 2015-22260 A

In the above embodiment, a correction value is added to the digital value related to the COS signal to perform the correction. However, the present invention is not limited to this. The correction value may be added to the digital value related to the SIN signal to perform the correction. The correction value may be integrated with the digital value related to the SIN signal or COS signal to perform the correction.

In the above embodiment, the rotation angle detection program is installed in the ROM 14, but the present disclosure is not limited to this. The rotation angle detection program according to the present disclosure may be provided in a form recorded on a computer-readable storage medium. For example, the rotation angle detection program according to the present disclosure may be provided in a form recorded on an optical disk such as a CD (Compact Disc)-ROM or a DVD (Digital Versatile Disc)-ROM. The rotation angle detection program according to the present disclosure may also be provided in a form recorded on a semiconductor memory such as a USB (Universal Serial Bus) memory or a memory card. Furthermore, the rotation angle detection device 10 may download the rotation angle detection program according to the present disclosure from an external device connected to a communication line (not shown) through a communication line (not shown).

The control unit and the method described in the present disclosure may be realized by a special-purpose computer having a processor programmed to execute one or more functions embodied in a computer program. Alternatively, the device and the method described in the present disclosure may be realized by a special-purpose computer having a processor configured by a dedicated hardware logic circuit. Alternatively, the device and the method described in the present disclosure may be realized by one or more special-purpose computers configured by a combination of a processor that executes a computer program and one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transient tangible recording medium as instructions executed by the computer.

Reference Signs List 1 Rotor 2 Stator 3 Permanent magnet 4 Rotor 5 Coil 10 Rotation angle detection device 11, 12 Hall element 13 Control unit 14 ROM
15 RAM
16: multiplexer 17: AD conversion circuit 19: bus 21A, 21B: acquisition unit 22A, 23B: setting unit 23: calculation unit

Claims (6)

an acquisition unit (21A, 21B) that acquires detection results from a first detection element (11) that detects a magnetic field of a magnetic field generating unit (3) provided on a detection target for detecting a rotation angle, and a second detection element (12) that detects the magnetic field and is disposed at a position having an angular difference of 90° electrical angle from the first detection element (11) along the rotation direction of the detection target;
a setting unit (22A, 22B) that sets a first digital value based on the acquired detection result of the first detection element (11) and sets a second digital value based on the acquired detection result of the second detection element (12) in accordance with an acquisition status of the detection result of the first detection element (11);
a calculation unit (23) that calculates a rotation angle of the detection object using the set first digital value and the set second digital value;
A rotation angle detection device comprising: the acquisition unit acquires the detection result by the first detection element and then acquires the detection result by the second detection element twice in succession,
The rotation angle detection device according to claim 1 , wherein the setting unit sets the second digital value based on a later one of two detection results by the second detection element. The rotation angle detection device according to claim 1 , wherein the setting unit corrects and sets the second digital value using a correction value that is determined in advance according to the detection result by the first detection element. The rotation angle detection device according to claim 3 , wherein the setting unit corrects the second digital value by adding the correction value to the second digital value. obtaining detection results from a first detection element that detects a magnetic field of a magnetic field generating unit provided on a detection target for which a rotation angle is to be detected, and a second detection element that detects the magnetic field and is disposed at a position having an angular difference of 90° electrical angle from the first detection element along a rotation direction of the detection target;
setting a first digital value based on the acquired detection result of the first detection element, and setting a second digital value based on the acquired detection result of the second detection element in accordance with an acquisition status of the detection result of the first detection element;
calculating a rotation angle of the detection object using the set first digital value and the set second digital value;
A rotation angle detection method in which processing is performed by a computer. at least one processor acquires detection results from a first detection element that detects a magnetic field of a magnetic field generating unit provided on a detection target for detecting a rotation angle, and a second detection element that detects the magnetic field and is disposed at a position having an angular difference of 90° electrical angle from the first detection element along a rotation direction of the detection target;
setting a first digital value based on the acquired detection result of the first detection element, and setting a second digital value based on the acquired detection result of the second detection element in accordance with an acquisition status of the detection result of the first detection element;
calculating a rotation angle of the detection object using the set first digital value and the set second digital value;
A rotation angle detection program for executing the process.