Position detection device

Abstract

A position detection device for detecting the position of a detection body (20, 100) is provided with: signal output units (32, 33, 61, 62) for outputting a first signal (V1) and a second signal (V2); an arrangement unit (30, 10) arranged so as to face the detection body; and a signal processing unit (50) that calculates the position of the detection body before correction by correcting the first signal and the second signal, and corrects the position of the detection body before correction by calculating a correction function obtained on the basis of the error of the position of the detection body before correction. The signal processing unit is provided with: a signal correction unit (54) that corrects the first signal and the second signal when the arrangement unit is arranged in a reference gap, one or more near gaps, and one or more far gaps, respectively, and derives a correction value in a correction function for each of the plurality of sections, or the signal processing unit is provided with: a signal correction unit (54) that corrects the first signal and the second signal; a position calculation unit (55) that calculates the position of the detection body before correction; and a section correction unit (56) that corrects the pre-correction detection body position for each of the plurality of sections.

Description

[0001] Cross-reference to Related Applications

[0002] This application is based on Japanese Patent Application No. 2022-183453 filed on November 16, 2022, and Japanese Patent Application No. 2023-166407 filed on September 27, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a position detection device. Background Art

[0004] Conventionally, a linear position sensor that detects the position of a detection object based on changes in a magnetic field received from a plurality of magnets disposed on the detection object has been known (for example, refer to Patent Document 1). The linear position sensor includes a detection unit that obtains sine signals and cosine signals having phases corresponding to the positions of a plurality of magnets on the moving detection object, and detects the position of the detection object based on the sine signals and cosine signals obtained by the detection unit.

[0005] In addition, the linear position sensor described in Patent Document 1 adjusts the magnetic field received by the detection unit unevenly by arranging the intervals of a plurality of magnets on the detection object at unequal intervals or arranging the heights of the magnets unevenly, thereby improving the detection accuracy at a specific position.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-16309 Summary of the Invention

[0009] According to the inventors' specific research, in a position detection device that detects the position of a detection object based on sine signals and cosine signals as in the linear position sensor described in Patent Document 1, there is room for improving the detection accuracy without being limited to a specific position.

[0010] An object of the present disclosure is to provide a position detection device capable of improving the detection accuracy.

[0011] According to one technical solution of the present disclosure, a position detection device for detecting the position of a detection object includes: a signal output unit that outputs a first sine-wave signal corresponding to the position of the detection object and a second signal corresponding to the position of the detection object, the second signal being a cosine-wave shape with a phase different from that of the first signal; a configuration unit provided with the signal output unit and configured to face the detection object in a state separated from the detection object; and a signal processing unit that calculates the position of the detection object, i.e., the detection object position, when the detection object is displaced within a specified detection range based on the first signal and the second signal; the signal processing unit corrects the first signal and the second signal, calculates the position of the detection object before correction, i.e., the pre-correction detection object position, based on the corrected first signal and the second signal, operates a correction function obtained from the error of the calculated pre-correction detection object position, and can correct the pre-correction detection object position calculated for each of the multiple intervals when the detection range is divided into multiple intervals; when the interval between the detection object and the configuration unit in the facing direction, i.e., the facing direction, is a gap, the reference gap is a reference gap, the near gap is a gap in which the interval between the detection object and the configuration unit is smaller than the reference gap, and the far gap is a gap in which the interval between the detection object and the configuration unit is larger than the reference gap, the first signal and the second signal are corrected so that the errors of the pre-correction detection object positions when the configuration unit is respectively configured at the reference gap, one or more of the near gaps, and one or more of the far gaps are respectively close to 0, and correction values in the correction function are derived for each of the multiple intervals.

[0012] In addition, according to another technical solution, there is a position detection device for detecting the position of a detection object, which includes: a signal output unit that outputs a first sine-wave signal corresponding to the position of the detection object and a second signal corresponding to the position of the detection object, where the second signal is a cosine-wave shape with a phase different from that of the first signal; a configuration unit where the signal output unit is provided and is configured to face the detection object in a state of being separated from the detection object; and a signal processing unit that calculates the position of the detection object, i.e., the detection object position, when the detection object moves within a specified detection range based on the first signal and the second signal. The signal processing unit has: a signal correction unit that corrects the first signal and the second signal; a position calculation unit that calculates the position of the detection object before correction, i.e., the pre-correction detection object position, based on the first signal and the second signal corrected by the signal correction unit; and an interval correction unit that operates on a correction function obtained from the error of the pre-correction detection object position calculated by the position calculation unit and corrects the pre-correction detection object position calculated by the position calculation unit for each of multiple intervals when the detection range is divided into multiple intervals. When the interval between the detection object and the configuration unit in the facing direction, i.e., the facing direction, is defined as a gap, the reference gap is defined as the reference gap, the near gap is defined as the gap where the interval between the detection object and the configuration unit is smaller than the reference gap, and the far gap is defined as the gap where the interval between the detection object and the configuration unit is larger than the reference gap, the signal correction unit corrects the first signal and the second signal such that the errors of the pre-correction detection object positions when the configuration unit is respectively configured at the reference gap, one or more near gaps, and one or more far gaps are each close to 0. The interval correction unit derives the correction value in the correction function for each of the multiple intervals.

[0013] Thus, when the interval between the detection object and the configuration unit is configured as one of the reference gap, near gap, and far gap, by deriving correction terms in a manner that makes the error of the detection object position close to 0, the detection error can be suppressed. Therefore, the detection accuracy of the position detection device can be improved.

[0014] In addition, the reference numerals in parentheses assigned to each component etc. represent an example of the correspondence between the component etc. and the specific components etc. described in the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of the position detection device according to the first embodiment.

[0016] Figure 2 It is Figure 1 a II-II cross-sectional view of

[0017] Figure 3 It is Figure 1 a III-III cross-sectional view of

[0018] Figure 4 It is a diagram showing the substrate related to the first embodiment.

[0019] Figure 5 It is a block diagram of the position detection device related to the first embodiment.

[0020] Figure 6 It is a diagram showing an example of the waveform of the first voltage value generated in the first receiving coil and the waveform of the second voltage value generated in the second receiving coil related to the first embodiment.

[0021] Figure 7 It is a diagram showing the details of the angle calculation unit in the block diagram of the position detection device related to the first embodiment.

[0022] Figure 8 It is a diagram showing an example of the waveform of the first voltage value generated in the ideal first receiving coil and the waveform of the second voltage value generated in the second receiving coil.

[0023] Figure 9 It is a diagram showing the relative relationship between the mechanical angle and the electrical angle.

[0024] Figure 10 It is a diagram showing an example of the rotation angle error.

[0025] Figure 11 It is a diagram showing an example of the rotation angle error before correction calculated by the position calculation unit related to the first embodiment.

[0026] Figure 12 It is a diagram for explaining that the offsets of the first conversion signal and the second conversion signal change corresponding to the gap.

[0027] Figure 13 It is a diagram showing an example of the corrected rotation angle error corrected by the interval correction unit related to the first embodiment.

[0028] Figure 14 It is a block diagram of the position detection device related to the first embodiment.

[0029] Figure 15 It is a diagram showing the substrate related to the second embodiment.

[0030] Figure 16 It is a diagram showing the rotating member related to the second embodiment.

[0031] Figure 17 It is a diagram showing the position detection device and the detection object related to the third embodiment.

[0032] Figure 18 It is a block diagram of the position detection device related to the third embodiment.

[0033] Figure 19 This is a diagram showing an example of the error in the rotation angle calculated by the position calculation unit according to the fourth embodiment.

[0034] Figure 20 This is a diagram showing an example of the error in the corrected rotation angle corrected by the interval correction unit according to the fourth embodiment.

[0035] Figure 21 This is a diagram showing the substrate according to the fifth embodiment. Detailed Embodiments

[0036] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, in the following embodiments, the same or equivalent parts as those already described in the previous embodiments are given the same reference numerals, and their descriptions may sometimes be omitted. Furthermore, in the embodiments, when only a part of the components is described, for the other parts of the components, the components already described in the previous embodiments can be applied. As long as there is no particular hindrance to the combination, the following embodiments can be partially combined with each other even without being particularly specified.

[0037] (First Embodiment)

[0038] Refer to Figures 1 to 12 This embodiment will be described. In this embodiment, an example in which the position detection device 1 is used to detect the rotational position of the brake pedal or the accelerator pedal of a vehicle pedal device will be described. In addition, in the following description, the brake pedal or the accelerator pedal may sometimes be simply referred to as the pedal.

[0039] As Figures 1 to 3 shown, the position detection device 1 of this embodiment includes a rotating member 20 and a substrate 30. In addition, the rotation axis CL shown in Figures 1 to 3 is the rotation axis 70 of the pedal and the rotation center of the rotating member 20. In this embodiment, the direction in which the rotation axis CL extends is defined as the axial direction Da, the direction that radiates radially around the axis of the rotation axis CL is defined as the radial direction Dr, and the rotation direction of the rotation axis CL is defined as the circumferential direction Dc for the description. These axial direction Da, radial direction Dr, and circumferential direction Dc are mutually intersecting directions, and strictly speaking, they are mutually perpendicular directions.

[0040] The rotating member 20 is made of metal and is formed in a flat plate shape having a thickness in the axial direction Da. The rotating member 20 is connected to the rotation axis 70 of the pedal so as not to be relatively rotatable. For example, the rotating member 20 can be non-rotatable relative to the rotation axis 70 either by a rotation prevention key member or by being welded to the rotation axis 70.

[0041] The rotating member 20 is a rotating body supported by a non-rotating member via a rotating shaft 70 so as to be rotatable about a specified rotation axis CL, and rotates integrally with the pedal and the rotating shaft 70. Accordingly, the position detection device 1 can detect the rotation position of the pedal by detecting the rotation position of the rotating member 20. That is, the rotation position of the rotating shaft 70 is also the rotation position of the pedal and the rotation position of the rotating member 20 as a detection object. The position detection device 1 of the present embodiment detects the rotation position of the pedal by detecting the rotation position of the rotating member 20.

[0042] In addition, since the rotating member 20 is connected to the rotating shaft 70 of the pedal, it does not rotate one full turn about the rotation axis CL, but reciprocates within a specified angular range about the rotation axis CL as the pedal is depressed. For example, in the present embodiment, by depressing the pedal, the rotating member 20 reciprocates within an angular range smaller than 0° to 360°, that is, within an angular range of 0° to 24° about the rotation axis CL. In Figure 1 the figure, a part of the outer shapes of four targets 22, 23, 24, and 25 of the rotating member 20 at the end positions during this reciprocating motion are illustrated by a double-dot chain line.

[0043] As Figure 1 shown, the rotating member 20 has a connecting portion 21 and four targets 22, 23, 24, and 25. That is, the four targets 22, 23, 24, and 25 included in the rotating member 20 rotate integrally about the rotation axis CL. Also, as the pedal is depressed, all four targets 22, 23, 24, and 25 reciprocate in the circumferential direction Dc.

[0044] For example, the rotating member 20 is configured as a single part including the connecting portion 21 and four targets 22, 23, 24, and 25. In addition, the rotating member 20 is formed in a flat plate shape with a uniform thickness in the axial direction Da. Therefore, the thicknesses of the four targets 22 to 25 in the axial direction Da are the same size. Further, in the description of the present embodiment, the four targets 22, 23, 24, and 25 may be collectively referred to as the four targets 22 to 25. In addition, the four targets 22 to 25 may be respectively referred to as the first target 22, the second target 23, the third target 24, and the fourth target 25.

[0045] The connecting portion 21 is disposed in the central portion of the rotating member 20 and has an annular shape centered on the rotation axis CL. An insertion hole 21a that penetrates the connecting portion 21 in the axial direction Da is formed inside the connecting portion 21. And the rotating shaft 70 is inserted into the insertion hole 21a so as not to be relatively rotatable with respect to the connecting portion 21. That is, the rotating member 20 is connected to the rotating shaft 70 through the connecting portion 21.

[0046] Four targets 22 to 25 are respectively formed so as to protrude outward from the connecting portion 21 in the radial direction Dr. The four targets 22 to 25 are arranged at equal intervals in the circumferential direction Dc. Specifically, the first target 22, the second target 23, the third target 24, and the fourth target 25 are arranged at intervals of 90 degrees in this order in the circumferential direction Dc. Moreover, the intervals of the four targets 22 to 25 in the circumferential direction Dc are set so that they can cover either the first positive vortex portion 32a or the first negative vortex portion 32b of the first receiving coil 32 described later. In addition, the intervals of the four targets 22 to 25 in the circumferential direction Dc are set so that they can cover either one of the second positive vortex portion 33a and the second negative vortex portion 33b of the second receiving coil 33 and one of the first positive vortex portion 32a and the first negative vortex portion 32b simultaneously.

[0047] The first target 22 is arranged on the opposite side of the third target 24 with the rotation axis CL interposed therebetween. In addition, the second target 23 is arranged on the opposite side of the fourth target 25 with the rotation axis CL interposed therebetween. And when observing in the direction along the axial direction Da, the four targets 22 to 25 are integrally arranged to be point-symmetrical about the rotation axis CL.

[0048] As Figure 3 shown, the first target 22 has a first opposed surface 22a formed on one side in the axial direction Da and opposed to the substrate 30. As Figure 2 shown, the second target 23 has a second opposed surface 23a formed on one side in the axial direction Da and opposed to the substrate 30. The third target 24 has a third opposed surface 24a formed on one side in the axial direction Da and opposed to the substrate 30. The fourth target 25 has a fourth opposed surface 25a formed on one side in the axial direction Da and opposed to the substrate 30. These first opposed surface 22a, second opposed surface 23a, third opposed surface 24a, and fourth opposed surface 25a are formed in parallel with the other surface 30b of the substrate 30 described later.

[0049] And, as Figure 1 shown, from the innermost part in the radial direction Dr to the substantially central part in the radial direction Dr of the first target 22, the size in the circumferential direction Dc becomes smaller as it goes toward the outside in the radial direction Dr. And from the substantially central part in the radial direction Dr to the outermost part in the radial direction Dr of the first target 22, the size in the circumferential direction Dc becomes larger as it goes toward the outside in the radial direction Dr. Therefore, when observing in the direction along the axial direction Da, the end portions on one side and the other side of the first target 22 in the circumferential direction Dc extend in a curved shape respectively.

[0050] In addition, the second target 23, the third target 24, and the fourth target 25 have the same shape as the first target 22. In the present embodiment, all of the four targets 22 to 25 have the same shape.

[0051] Thus, when viewed in the direction of the axial direction Da, the end portions on one side and the other side in the circumferential direction Dc of the second target 23 extend in a curved shape, respectively. In addition, when viewed in the direction of the axial direction Da, the end portions on one side and the other side in the circumferential direction Dc of the third target 24 extend in a curved shape, respectively. Further, when viewed in the direction of the axial direction Da, the end portions on one side and the other side in the circumferential direction Dc of the fourth target 25 extend in a curved shape, respectively.

[0052] In the present embodiment, as described above, all four targets 22 to 25 have the same shape and rotate integrally. Therefore, the operating ranges of the four targets 22 to 25 are of the same length in the circumferential direction Dc. Here, the operating range of the first target 22 is set as the first operating range W1, the operating range of the second target 23 is set as the second operating range W2, the operating range of the third target 24 is set as the third operating range W3, and the operating range of the fourth target 25 is set as the fourth operating range W4.

[0053] The first operating range W1 is the maximum range in the circumferential direction Dc that the first target 22 reaches as the first target 22 reciprocates. Therefore, the first target 22 reciprocates in the circumferential direction Dc within the first operating range W1. In addition, the second operating range W2 is the maximum range in the circumferential direction Dc that the second target 23 reaches as the second target 23 reciprocates. Therefore, the second target 23 reciprocates in the circumferential direction Dc within the second operating range W2. The third operating range W3 is the maximum range in the circumferential direction Dc that the third target 24 reaches as the third target 24 reciprocates. Therefore, the third target 24 reciprocates in the circumferential direction Dc within the third operating range W3. The fourth operating range W4 is the maximum range in the circumferential direction Dc that the fourth target 25 reaches as the fourth target 25 reciprocates. Therefore, the fourth target 25 reciprocates in the circumferential direction Dc within the fourth operating range W4.

[0054] The substrate 30 is a multilayer printed substrate on which a wiring pattern is formed and electronic components (not shown) are mounted. Specifically, the substrate 30 is made into a multilayer substrate in which an insulating film and a wiring layer are alternately laminated. And, although not particularly shown in the substrate 30, various electronic components such as resistors are appropriately arranged, for example.

[0055] In addition, the substrate 30 has a planar one surface 30a and the other surface 30b that are orthogonal to the axial direction Da. That is, the normal direction of the substrate 30 is consistent with the axial direction Da. One surface 30a of the substrate 30 is provided on one side in the axial direction Da of the substrate 30. The other surface 30b of the substrate 30 is provided on the other side opposite to the one side in the axial direction Da of the substrate 30.

[0056] The substrate 30 is a non-rotating component that does not rotate relative to the pedal. Thus, the rotating component 20 rotates relative to the substrate 30.

[0057] The substrate 30 is disposed on one side in the axial direction Da with respect to the four targets 22 to 25. And, the other surface 30b of the substrate 30 is opposed to the first opposed surface 22a, the second opposed surface 23a, the third opposed surface 24a, and the fourth opposed surface 25a of the four targets 22 to 25 with a predetermined interval in the axial direction Da, respectively. In other words, the substrate 30 is disposed opposed to the rotating component 20 in a state of being separated from the rotating component 20 in the opposed direction, which is the direction opposed to the rotating component 20. The predetermined interval in the axial direction Da between the substrate 30 and the rotating component 20 is the same size between the substrate 30 and each of the four targets 22 to 25. Hereinafter, the predetermined interval in the axial direction Da between the substrate 30 and the rotating component 20 is also referred to as the gap G.

[0058] In addition, the substrate 30 is formed in a disk shape centered on the rotation axis CL. And, in the center of the substrate 30, a through hole 30c that penetrates the substrate 30 in the axial direction Da is formed. The rotating shaft 70 is inserted through the through hole 30c.

[0059] As Figure 1 、 Figure 4 、 Figure 5 shown, the substrate 30 has one transmitting coil 31, eight first receiving coils 32, eight second receiving coils 33, and a signal processing circuit 40 described later, which are formed as wiring patterns. One transmitting coil 31, eight first receiving coils 32, eight second receiving coils 33, and the signal processing circuit 40 described later provided in the position detection device 1 are formed on a single substrate 30. In addition, one transmitting coil 31, eight first receiving coils 32, and eight second receiving coils 33 are formed in wiring layers formed in respective layers of a multilayer substrate. And, one transmitting coil 31, eight first receiving coils 32, and eight second receiving coils 33 formed in each layer are appropriately connected via via holes 34.

[0060] These one transmitting coil 31, eight first receiving coils 32, and eight second receiving coils 33 are respectively connected to the signal processing circuit 40 described later, which is composed of an IC or the like mounted on the substrate 30, via connection wiring patterns not shown. The substrate 30 corresponds to the arrangement portion where these one transmitting coil 31, eight first receiving coils 32, eight second receiving coils 33, and the signal processing circuit 40 are arranged.

[0061] The transmitting coil 31 is formed in a circular ring shape by being wound multiple times. And, when viewed in the direction along the axial direction Da, the transmitting coil 31 is formed so as to surround the eight first receiving coils 32 and the eight second receiving coils 33 that the substrate 30 has. In other words, when viewed in the direction along the axial direction Da, the transmitting coil 31 is disposed outside the eight first receiving coils 32 and the eight second receiving coils 33. And, inside the transmitting coil 31, the eight first receiving coils 32 and the eight second receiving coils 33 are alternately arranged and disposed in the circumferential direction Dc.

[0062] The eight first receiving coils 32 and the eight second receiving coils 33 of the present embodiment are respectively as Figure 4 shown, mainly in a spiral shape. And, the eight first receiving coils 32 each have a first positive spiral portion 32a and a first negative spiral portion 32b. The first positive spiral portion 32a and the first negative spiral portion 32b are the portions that form a spiral shape in each of the eight first receiving coils 32. And, the first positive spiral portion 32a and the first negative spiral portion 32b of each of the eight first receiving coils 32 face one of the four targets 22 to 25 in the axial direction Da. In addition, the eight first receiving coils 32 are electrically connected in one stroke via their respective first positive spiral portions 32a and first negative spiral portions 32b.

[0063] In addition, the eight second receiving coils 33 of the present embodiment each have a second positive spiral portion 33a and a second negative spiral portion 33b. The second positive spiral portion 33a and the second negative spiral portion 33b are the portions that form a spiral shape in each of the eight second receiving coils 33. And, the second positive spiral portion 33a and the second negative spiral portion 33b of each of the eight second receiving coils 33 face one of the four targets 22 to 25 in the axial direction Da. In addition, the eight second receiving coils 33 are electrically connected in one stroke via their respective second positive spiral portions 33a and second negative spiral portions 33b.

[0064] The shapes of the first positive spiral portion 32a and the first negative spiral portion 32b of each of the eight first receiving coils 32 are the same. Therefore, only the detailed situation of the first receiving coil 32 facing the target 22 will be described below, and the detailed description of the first receiving coils 32 facing the remaining three targets 23 to 25 will be omitted.

[0065] In addition, the shapes of the second positive spiral portion 33a and the second negative spiral portion 33b of each of the eight second receiving coils 33 are the same. Therefore, only the detailed situation of the second receiving coil 33 facing the target 22 will be described below, and the detailed description of the second receiving coils 33 facing the remaining three targets 23 to 25 will be omitted.

[0066] The first positive vortex portion 32a and the first negative vortex portion 32b of the first receiving coil 32, and the second positive vortex portion 33a and the second negative vortex portion 33b of the second receiving coil 33 are formed by being arranged at a predetermined interval along the circumferential direction Dc. Specifically, the first positive vortex portion 32a, the second positive vortex portion 33a, the first negative vortex portion 32b, and the second negative vortex portion 33b are formed in this order from one side to the other side of the circumferential direction Dc of the substrate 30.

[0067] The first positive vortex portion 32a and the first negative vortex portion 32b are formed in a spiral pattern shape that depicts a quadrilateral while changing the diameter. Also, the first positive vortex portion 32a and the first negative vortex portion 32b are wound with coils in the same direction multiple times in each of the plurality of wiring layers of the substrate 30. The first positive vortex portion 32a and the first negative vortex portion 32b formed in each of the plurality of wiring layers of the substrate 30 are formed so as to overlap in the normal direction. However, the winding directions of the coils of the first positive vortex portion 32a and the first negative vortex portion 32b (i.e., the directions of the vortices) are opposite to each other. For example, when observed in the direction along the normal direction, the winding direction of the coil of the first positive vortex portion 32a is clockwise. In contrast, when observed in the direction along the normal direction, the winding direction of the coil of the first negative vortex portion 32b is counterclockwise.

[0068] The second positive vortex portion 33a and the second negative vortex portion 33b are, like the first positive vortex portion 32a and the first negative vortex portion 32b, formed in a spiral pattern shape that depicts a quadrilateral while changing the diameter. Also, the second positive vortex portion 33a and the second negative vortex portion 33b are, like the first positive vortex portion 32a and the first negative vortex portion 32b, wound with coils in the same direction multiple times in each of the plurality of wiring layers of the substrate 30. The second positive vortex portion 33a and the second negative vortex portion 33b formed in each of the plurality of wiring layers of the substrate 30 are formed so as to overlap in the normal direction. However, the directions of the vortices of the second positive vortex portion 33a and the second negative vortex portion 33b are opposite to each other. For example, the second positive vortex portion 33a is wound with a clockwise coil. In contrast, the second negative vortex portion 33b is wound with a counterclockwise coil.

[0069] The first receiving coil 32 and the second receiving coil 33 among the eight first receiving coils 32 and the eight second receiving coils 33 that face the first target 22 are coils for detecting the position of the first target 22 on the circumferential direction Dc.

[0070] Moreover, the first positive vortex portion 32a and the first negative vortex portion 32b of the first receiving coil 32 are arranged such that at least a part of them overlaps with the first target 22 on one side in the axial direction Da at a certain position within the first operation range W1 of the first target 22. In addition, the second positive vortex portion 33a and the second negative vortex portion 33b of the second receiving coil 33 are arranged such that at least a part of them overlaps with the first target 22 on one side in the axial direction Da at a certain position within the first operation range W1 of the first target 22.

[0071] Therefore, the first receiving coil 32 and the second receiving coil 33 among the eight first receiving coils 32 and the eight second receiving coils 33 that face the first target 22 output detection signals corresponding to the position of the first target 22. The first receiving coil 32 and the second receiving coil 33 that face the first target 22 function as signal output portions that output signals corresponding to the rotational position of the rotating member 20.

[0072] The detection signals output by the first receiving coil 32 and the second receiving coil 33 are, for example, voltage values. In addition, the detection signal output by the first receiving coil 32 is the first signal output by the first receiving coil 32 that functions as a signal output portion, and is, for example, equivalent to the first voltage value V1 shown later. Figure 5 In addition, the detection signal output by the second receiving coil 33 is the second signal output by the second receiving coil 33 that functions as a signal output portion, and is, for example, equivalent to the second voltage value V2 shown later. Figure 5 shown in

[0073] Moreover, the first receiving coil 32 and the second receiving coil 33 that face the second target 23 are coils for detecting the position of the second target 23 in the circumferential direction Dc. Therefore, the first receiving coil 32 and the second receiving coil 33 that face the second target 23 output detection signals corresponding to the position of the second target 23.

[0074] And, the first receiving coil 32 and the second receiving coil 33 that face the third target 24 are coils for detecting the position of the third target 24 in the circumferential direction Dc. Therefore, the first receiving coil 32 and the second receiving coil 33 that face the third target 24 output detection signals corresponding to the position of the third target 24.

[0075] In addition, the first receiving coil 32 and the second receiving coil 33 opposed to the fourth target 25 are coils for detecting the position of the fourth target 25 in the circumferential direction Dc. Therefore, the first receiving coil 32 and the second receiving coil 33 opposed to the fourth target 25 output detection signals corresponding to the position of the fourth target 25. Therefore, the first receiving coil 32 and the second receiving coil 33 opposed to the second target 23, the third target 24, and the fourth target 25 respectively function as signal output units that output signals corresponding to the rotational position of the rotating member 20.

[0076] And, as Figure 4 shown, the first positive vortex portions 32a and the first negative vortex portions 32b of the eight first receiving coils 32, and the second positive vortex portions 33a and the second negative vortex portions 33b of the eight second receiving coils 33 are arranged in a circular ring shape centered on the rotation axis CL in the circumferential direction Dc. Specifically, the first positive vortex portions 32a and the first negative vortex portions 32b of the eight first receiving coils 32, and the second positive vortex portions 33a and the second negative vortex portions 33b of the eight second receiving coils 33 are arranged at intervals of 20 degrees in the circumferential direction Dc centered on the rotation axis CL.

[0077] As described above, the first target 22 reciprocates in the circumferential direction Dc within the first operation range W1. And the first target 22 is configured such that it does not overlap with the first receiving coil 32 and the second receiving coil 33 opposed to the second target 23, the third target 24, and the fourth target 25 in the axial direction Da.

[0078] In addition, the second target 23 reciprocates in the circumferential direction Dc within the second operation range W2. And the second target 23 is configured such that it does not overlap with the first receiving coil 32 and the second receiving coil 33 opposed to the first target 22, the third target 24, and the fourth target 25 in the axial direction Da.

[0079] And the third target 24 reciprocates in the circumferential direction Dc within the third operation range W3. And the third target 24 is configured such that it does not overlap with the first receiving coil 32 and the second receiving coil 33 opposed to the first target 22, the second target 23, and the fourth target 25 in the axial direction Da.

[0080] In addition, the fourth target 25 reciprocates in the circumferential direction Dc within the fourth operation range W4. And the fourth target 25 is configured such that it does not overlap with the first receiving coil 32 and the second receiving coil 33 opposed to the first target 22, the second target 23, and the third target 24 in the axial direction Da.

[0081] In addition, as Figure 5As shown, various electronic components are mounted on the substrate 30 in addition to one transmitting coil 31, eight first receiving coils 32, eight second receiving coils 33, and the signal processing circuit 40. For example, on the substrate 30, connection wirings 35 are formed to connect one transmitting coil 31, eight first receiving coils 32, and eight second receiving coils 33 to the signal processing circuit 40. Further, the signal processing circuit 40 is connected to these one transmitting coil 31, eight first receiving coils 32, and eight second receiving coils 33 via the connection wirings 35.

[0082] The signal processing circuit 40 is configured to include a microcomputer or the like having a storage unit including a CPU and storage units such as a ROM, a RAM, and a non-volatile RAM, and is connected to the transmitting coil 31, the first receiving coil 32, and the second receiving coil 33. Further, the signal processing circuit 40 reads out a program from the ROM or the non-volatile RAM by the CPU and executes the program to thereby achieve various control operations. In addition, various data (for example, initial values, look-up tables, mapping tables, etc.) used when the program is executed are stored in advance in the ROM or the non-volatile RAM. Further, the storage medium such as the ROM is a non-transitory physical storage medium. The CPU is an abbreviation for Central Processing Unit, that is, a central processing unit, the ROM is an abbreviation for Read Only Memory, that is, a read-only memory, and the RAM is an abbreviation for Random Access Memory, that is, a random access memory.

[0083] Specifically, as Figure 5 shown, the signal processing circuit 40 includes a signal processing unit 50 that is connected to one transmitting coil 31, eight first receiving coils 32, and eight second receiving coils 33 and performs predetermined processing. The signal processing unit 50 includes an oscillation unit 51, a demodulation unit 52, an AD conversion unit 53, an angle calculation unit 80, an output unit 57, and a power supply unit 58. In addition, hereinafter, an example in which processing is performed by converting into a digital signal is taken as a representative example for description, but in the case where processing is performed by an analog signal, the signal processing unit 50 may not include the AD conversion unit 53 or the like.

[0084] In addition, in the present embodiment, the eight first receiving coils 32 and the eight second receiving coils 33 respectively output voltage values corresponding to the positions of the four targets 22 to 25. Further, the control processing executed by the signal processing unit 50 when voltage values are respectively output from the eight first receiving coils 32 and the eight second receiving coils 33 to the signal processing unit 50 is the same.

[0085] Therefore, in Figure 5Among them, only the first receiving coils 32 and the second receiving coils 33 facing the first target 22 are described in the eight first receiving coils 32 and the eight second receiving coils 33. And the following describes the first voltage value V1 and the second voltage value V2 when the first receiving coil 32 and the second receiving coil 33 facing the first target 22 output voltage values corresponding to the position of the first target 22. The first voltage value V1 is the voltage value output by the first receiving coil 32 corresponding to the position of the first target 22. The second voltage value V2 is the voltage value output by the second receiving coil 33 corresponding to the position of the first target 22.

[0086] First, the transmitting coil 31 is applied with an alternating current of a specified frequency from the oscillation unit 51. Thereby, electromagnetic induction is generated in the transmitting coil 31. Then, through the generated electromagnetic induction, the transmitting coil 31 is inductively coupled to the first receiving coil 32. In addition, through the generated electromagnetic induction, the transmitting coil 31 is inductively coupled to the second receiving coil 33. And around the first positive vortex portion 32a and the first negative vortex portion 32b of the first receiving coil 32, and around the second positive vortex portion 33a and the second negative vortex portion 33b of the second receiving coil 33, a magnetic field passing through the first receiving coil 32 and the second receiving coil 33 in the axial direction Da is generated. In addition, since the magnetic field generated by the alternating current changes, the first voltage value V1, which is the induced electromotive force generated in the first receiving coil 32, and the second voltage value V2, which is the induced electromotive force generated in the second receiving coil 33, change through electromagnetic induction.

[0087] And if the first target 22 faces the first receiving coil 32 and the second receiving coil 33, then eddy currents, which are induced currents, are generated in the first target 22 through electromagnetic induction and a magnetic field caused by the eddy currents is generated. Therefore, in the magnetic field in the axial direction Da passing through the first receiving coil 32 and the second receiving coil 33, the magnetic field passing through the portion facing the first target 22 is canceled by the magnetic field caused by the eddy currents. Thereby, the first voltage value V1 generated in the first receiving coil 32 and the second voltage value V2 generated in the second receiving coil 33 change.

[0088] And as the rotating member 20 rotates, the area of the first receiving coil 32 and the second receiving coil 33 facing the first target 22 changes. Then, the magnitude of the portion of the magnetic field in the axial direction Da passing through the first receiving coil 32 and the second receiving coil 33 and facing the first target 22 changes periodically. Thus, the rotating member 20 of the present embodiment causes the first voltage value V1 generated in the first receiving coil 32 and the second voltage value V2 generated in the second receiving coil 33 to change according to its own rotation position.

[0089] Therefore, as Figure 6As shown, as the rotational position of the rotating member 20 changes, the first voltage value V1 generated in the first receiving coil 32 and the second voltage value V2 generated in the second receiving coil 33 change periodically.

[0090] And, for example, when the portion of the first target 22 facing the first counter-vortex portion 32b in the first receiving coil 32 is larger than the portion of the first target 22 facing the first positive-vortex portion 32a in the first receiving coil 32, the first voltage value V1 becomes a voltage value on the positive side relative to the center of the amplitude in the sine-wave-shaped first voltage value V1. Further, for example, when the portion of the first target 22 facing the first positive-vortex portion 32a in the first receiving coil 32 is larger than the portion of the first target 22 facing the first counter-vortex portion 32b in the first receiving coil 32, a voltage value on the negative side relative to the center of the amplitude in the sine-wave-shaped first voltage value V1 is output.

[0091] And, for example, when the portion of the first target 22 facing the second counter-vortex portion 33b in the second receiving coil 33 is larger than the portion of the first target 22 facing the second positive-vortex portion 33a in the second receiving coil 33, the second voltage value V2 becomes a voltage value on the positive side relative to the center of the amplitude in the cosine-wave-shaped second voltage value V2. Further, for example, when the portion of the first target 22 facing the second positive-vortex portion 33a in the second receiving coil 33 is larger than the portion of the first target 22 facing the second counter-vortex portion 33b in the second receiving coil 33, a voltage value on the negative side relative to the center of the amplitude in the cosine-wave-shaped second voltage value V2 is output.

[0092] Moreover, the first receiving coil 32 and the second receiving coil 33 are formed such that the waveforms of the first voltage value V1 and the second voltage value V2 are electrically angled 90° apart. Therefore, in the present embodiment, the first voltage value V1 generated in the first receiving coil 32 becomes a sine wave corresponding to the rotational position of the first target 22. Further, the second voltage value V2 generated in the second receiving coil 33 is a waveform with a phase different from that of the first voltage value V1 and becomes a cosine wave corresponding to the rotational position of the first target 22.

[0093] In addition, regarding the substrate 30 of the present embodiment, eight first receiving coils 32 and eight second receiving coils 33 are arranged in an annular shape centered on the rotation axis CL in the circumferential direction Dc. And, assuming that the rotating member 20 can rotate 360°, during one rotation of the rotating member 20, the four targets 22 to 25 respectively pass in front of the eight first receiving coils 32 and the eight second receiving coils 33.

[0094] As the position detection device 1 of such a structure, the first receiving coil 32 and the second receiving coil 33 of the substrate 30 have a four-pole structure. Moreover, the first receiving coil 32 and the second receiving coil 33 having a four-pole structure have the voltage values outputted by the eight first receiving coils 32 and the eight second receiving coils 33 respectively changing positive and negative four times during one rotation of the rotating member 20. That is, during one rotation within the range of the mechanical angle, which is the rotation angle of the rotating member 20, from 0° to 360°, the electrical angle of the first receiving coil 32 and the second receiving coil 33 rotates four times within the range of 0° to 360°. In other words, one rotation of the electrical angle, that is, the rotation range of 0° to 360°, corresponds to the rotation range of the mechanical angle from 0° to 90°.

[0095] Next, the operation of the signal processing unit 50 will be described. The signal processing unit 50 is a calculation unit that calculates the rotation position of the rotating member 20 based on the first voltage value V1 outputted by the first receiving coil 32 and the second voltage value V2 outputted by the second receiving coil 33. That is, the signal processing unit 50 is a calculation unit that calculates the detection body position, which is the position of the detection body, that is, the rotating member 20.

[0096] As Figure 5 shown, the oscillation unit 51 is connected to both ends of the transmitting coil 31 and applies an alternating current of a specified frequency. In addition, between both ends of the transmitting coil 31 and the oscillation unit 51, two capacitors 36 and 37 are connected in series, and the portion connecting the two capacitors 36 and 37 to each other is connected to the ground potential. Moreover, the transmitting coil 31 generates a magnetic field on the axial direction Da passing through the first receiving coil 32 and the second receiving coil 33. However, the connection method of the transmitting coil 31 and the oscillation unit 51 can be appropriately changed. For example, one capacitor can also be arranged between both ends of the transmitting coil 31 and the oscillation unit 51.

[0097] The demodulation unit 52 is connected to both ends of the first receiving coil 32 and both ends of the second receiving coil 33. Moreover, the demodulation unit 52 generates a first demodulation signal VD1 obtained by demodulating the first voltage value V1 of the first receiving coil 32, and generates a second demodulation signal VD2 obtained by demodulating the second voltage value V2 of the second receiving coil 33.

[0098] The AD conversion unit 53 is connected to the demodulation unit 52 and the angle calculation unit 80. Moreover, the AD conversion unit 53 outputs a first conversion signal Si obtained by performing AD conversion on the first demodulation signal VD1 and a second conversion signal Co obtained by performing AD conversion on the second demodulation signal VD2 to the angle calculation unit 80.

[0099] In addition, with respect to the magnetic field on the axial direction Da passing through the first receiving coil 32 and the second receiving coil 33, the magnetic flux changes based on the size of the gap G between the rotating member 20 and the substrate 30. Therefore, the first voltage value V1 generated in the first receiving coil 32 due to the magnetic field passing through the first receiving coil 32 on the axial direction Da changes based on the gap G between the rotating member 20 and the substrate 30. In addition, the second voltage value V2 generated in the second receiving coil 33 due to the magnetic field passing through the second receiving coil 33 on the axial direction Da changes based on the gap G between the rotating member 20 and the substrate 30.

[0100] Thus, the first conversion signal Si obtained based on the first voltage value V1 of the first receiving coil 32 and the second conversion signal Co obtained based on the second voltage value V2 of the second receiving coil 33, as Figure 6 shown, have amplitudes that change corresponding to the gap G. Specifically, for the first conversion signal Si obtained based on the first voltage value V1 and the second conversion signal Co obtained based on the second voltage value V2, the longer the gap G, the smaller the amplitude, and the shorter the gap G, the larger the amplitude.

[0101] Here, in Figure 6 an example of the change in the amplitudes of the first conversion signal Si and the second conversion signal Co corresponding to the gap G is shown in the case where the rotation range of the rotating member 20 is a mechanical angle of 0° to 90° and the range of the electrical angles of the first receiving coil 32 and the second receiving coil 33 is 0° to 360°. Specifically, the solid line a represents the first conversion signal Si when the gap G is set to 2 mm. The solid line b represents the first conversion signal Si when the gap G is set to 2.5 mm. The solid line c represents the first conversion signal Si when the gap G is set to 3 mm. The solid line d represents the first conversion signal Si when the gap G is set to 3.5 mm. The solid line e represents the first conversion signal Si when the gap G is set to 4 mm.

[0102] In addition, Figure 6 the solid line f in

[0103] represents the second conversion signal Co when the gap G is set to 2 mm. The solid line g represents the second conversion signal Co when the gap G is set to 2.5 mm. The solid line h represents the second conversion signal Co when the gap G is set to 3 mm. The solid line i represents the second conversion signal Co when the gap G is set to 3.5 mm. The solid line j represents the second conversion signal Co when the gap G is set to 4 mm. Figure 8 The explanations for the above solid lines a, b, c, d, e, f, g, h, i, and j are the same in the

[0104] Thus, the amplitude of the first conversion signal Si obtained based on the first voltage value V1 and the second conversion signal Co obtained based on the second voltage value V2 changes corresponding to the gap G. In addition, although the specific situation will be described later, when the position calculation unit 55 calculates the rotation angle θ, the position calculation unit 55 calculates the rotation angle θ based on the first conversion signal Si obtained based on the first voltage value V1 and the second conversion signal Co obtained based on the second voltage value V2. Therefore, when assembling the rotating member 20 and the substrate 30 to the rotating shaft 70, it is preferable to set the gap G to a preset design value. Thereby, when the angle is calculated by the position calculation unit 55, the rotation angle θ can be calculated in consideration of the magnitude of the amplitude corresponding to the gap G.

[0105] However, due to the assembly error and manufacturing error when assembling the rotating member 20 and the substrate 30 to the rotating shaft 70, the gap G between the rotating member 20 and the substrate 30 may deviate from the design value. For example, when the design value of the gap G is 3 mm, due to the assembly error and manufacturing error when assembling the rotating member 20 and the substrate 30 to the rotating shaft 70, there is also a case where the actual gap G deviates from 3 mm to 2 mm or 4 mm. And if the amplitudes of the first conversion signal Si and the second conversion signal Co change due to the deviation of the gap G from the design value, it becomes a cause of error in the calculation result when the position calculation unit 55 calculates the rotation angle θ based on the first conversion signal Si and the second conversion signal Co.

[0106] In addition, when the first conversion signal Si obtained based on the first voltage value V1 is in a sine wave shape, the gain, offset, and phase of the sine wave-shaped first conversion signal Si change according to the gap G. Thereby, the first conversion signal Si obtained based on the first voltage value V1 may be distorted from the ideal sine wave shape according to the gap G. In this case, the shape represented by the first conversion signal Si obtained based on the first voltage value V1 is a sine wave shape distorted with respect to the shape of the ideal sine wave. In other words, the first voltage value V1 becomes a sine wave shape including distortion.

[0107] In addition, when the second conversion signal Co obtained based on the second voltage value V2 is in a cosine wave shape, the gain, offset, and phase of the cosine wave-shaped second conversion signal Co change according to the gap G. Thereby, the second conversion signal Co obtained based on the second voltage value V2 may be distorted from the ideal sine wave shape according to the gap G. In this case, the shape represented by the second conversion signal Co obtained based on the second voltage value V2 is a cosine wave shape distorted with respect to the shape of the ideal cosine wave. In other words, the second voltage value V2 becomes a cosine wave shape including distortion.

[0108] Such a first transformed signal Si being distorted from an ideal sine wave and a second transformed signal Co being distorted from an ideal cosine wave also become causes of errors in the calculation result when the position calculation unit 55 calculates the rotation angle θ.

[0109] Therefore, the angle calculation unit 80 corrects the gain (G), offset (O), and phase (P) respectively used when calculating the rotation angle θ using the first transformed signal Si and the second transformed signal Co, thereby correcting the first transformed signal Si and the second transformed signal Co. And the angle calculation unit 80 uses the corrected first transformed signal Si and second transformed signal Co to calculate the arctangent function, derives the tanθ described later for angle calculation, and calculates the position of the rotating member 20 based on the derived tanθ. For example, as Figure 7 shown, the angle calculation unit 80 of the present embodiment includes a GOP correction unit 54 that corrects the first transformed signal Si and the second transformed signal Co, a position calculation unit 55 that calculates the rotation angle θ, and an interval correction unit 56 that corrects the rotation angle θ calculated by the position calculation unit 55.

[0110] The signal processing unit 50 of the present embodiment is configured to be able to function as the GOP correction unit 54, the position calculation unit 55, and the interval correction unit 56. In addition, the signal processing unit 50 may have a structure of one circuit module capable of functioning as the GOP correction unit 54, the position calculation unit 55, and the interval correction unit 56. Or, the signal processing unit 50 may be configured to include a plurality of circuit modules corresponding one-to-one to the GOP correction unit 54, the position calculation unit 55, and the interval correction unit 56.

[0111] The GOP correction unit 54 corrects the first transformed signal Si and the second transformed signal Co using at least one of the correction terms for gain, offset, and phase for each of the first transformed signal Si and the second transformed signal Co. And, using the corrected first transformed signal Si and second transformed signal Co and the following Equation 1, tanθ is derived. In this way, the GOP correction unit 54 that corrects the first voltage value V1 after being transformed into the first transformed signal Si using the first correction term described later and the second voltage value V2 after being transformed into the second transformed signal Co using the second correction term described later functions as a signal correction unit. In other words, the GOP correction unit 54 corrects the first transformed signal Si based on the first voltage value V1 and the second transformed signal Co based on the second voltage value V2.

[0112] (Equation 1)

[0113]

[0114] Further, in the above Equation 1, A1 is a gain correction term for correcting the gain of the first conversion signal Si, and A2 is a gain correction term for correcting the gain of the second conversion signal Co. In addition, in the above Equation 1, B1 is an offset correction term for correcting the offset of the first conversion signal Si, and B2 is an offset correction term for correcting the offset of the second conversion signal Co. Also, in the above Equation 1, C is a phase correction term for correcting the phases of the first conversion signal Si and the second conversion signal Co respectively. As shown in Equation 1, Equation 1 is an equation obtained from the first conversion signal Si based on the first voltage value V1 in a sine wave form and the second conversion signal Co based on the second voltage value V2 in a cosine form.

[0115] Hereinafter, the gain correction term for correcting the gain of the first conversion signal Si will also be referred to as the first gain correction term, and the offset correction term for correcting the offset of the first conversion signal Si will be referred to as the first offset correction term. In addition, the gain correction term for correcting the gain of the second conversion signal Co will also be referred to as the second gain correction term, and the offset correction term for correcting the offset of the second conversion signal Co will be referred to as the second offset correction term. Also, the phase correction term for correcting the phases of the first conversion signal Si and the second conversion signal Co respectively will simply be referred to as the phase correction term.

[0116] In addition, in the present embodiment, the first gain correction term and the first offset correction term correspond to the first correction term, and the second gain correction term and the second offset correction term correspond to the second correction term. Also, hereinafter, there will be cases where the first gain correction term and the first offset correction term are simply referred to as the first correction term, and the second gain correction term and the second offset correction term are simply referred to as the second correction term.

[0117] These first correction term, second correction term, and phase correction term can be obtained, for example, by inputting the first conversion signal Si and the second conversion signal Co obtained in a state where the rotating member 20 and the substrate 30 are pre-assembled on the rotating shaft 70 into an external device different from the position detection device 1. The external device can also be composed of a microcomputer having a CPU, a storage unit such as a ROM, a RAM, a non-volatile RAM, and an input / output interface. In this case, the external device can derive the first correction term, the second correction term, and the phase correction term based on the control program stored in the ROM or the like and the input first conversion signal Si and second conversion signal Co.

[0118] The external device sends the information of the derived first correction term, second correction term, and phase correction term to the GOP correction unit 54 for storage. Thus, when the GOP correction unit 54 receives the first conversion signal Si and the second conversion signal Co output from the AD conversion unit 53, it uses the stored first correction term, second correction term, and phase correction term to correct the first conversion signal Si and the second conversion signal Co. Further, the GOP correction unit 54 derives tanθ for the angle calculation by the position calculation unit 55 through Equation 1.

[0119] Here, the GOP correction unit 54 of the present embodiment corrects the first conversion signal Si and the second conversion signal Co using the first gain correction term, first offset correction term, second gain correction term, second offset correction term among the first gain correction term, first offset correction term, second gain correction term, second offset correction term, and phase correction term. Therefore, the GOP correction unit 54 of the present embodiment does not correct the phases of the first conversion signal Si and the second conversion signal Co respectively. Thus, the GOP correction unit 54 of the present embodiment uses Equation 1 in which 1 is substituted for C as the phase correction term to derive tanθ.

[0120] Here, a method for deriving the first gain correction term, first offset correction term, second gain correction term, and second offset correction term will be described. The first gain correction term and the first offset correction term are derived to make the first conversion signal Si approximate to Figure 8 the ideal sine wave shape as shown. Further, the second gain correction term and the second offset correction term are derived to make the second conversion signal Co approximate to Figure 8 the ideal cosine wave shape as shown. Furthermore, the first gain correction term, first offset correction term, second gain correction term, and second offset correction term are derived to make the differences between the errors when the gap G is the design value and the errors when the gap G deviates from the design value smaller respectively.

[0121] Here, it is assumed that the first conversion signal Si is Figure 6 in the sine wave shape as shown, and the second conversion signal Co is Figure 6 in the cosine wave shape as shown. Figure 6 The first conversion signal Si shown is a sine wave shape that includes distortion with respect to the shape of the ideal sine wave and has frequency components (not shown) superimposed thereon. Further, Figure 6 the second conversion signal Co shown is a cosine wave shape that includes distortion with respect to the shape of the ideal cosine wave and has frequency components (not shown) superimposed thereon.

[0122] In such a case, correction terms for the first gain and correction terms for the first offset are derived so that the first transformed signal Si approximates an ideal sine wave shape. Further, correction terms for the second gain and correction terms for the second offset are derived so that the second transformed signal Co approximates an ideal cosine wave shape.

[0123] Further, the position detection device 1 of the present embodiment is used to detect the rotational position of a pedal that reciprocates within a specified angular range around the rotation axis CL. Specifically, the position detection device 1 of the present embodiment detects the rotational position of a rotating member 20 that reciprocates within an angular range of 0° to 24° around the rotation axis CL by performing a stepping operation on the pedal. In this case, the detection range of the rotating member 20 detected by the position detection device 1 is from 0° to 24°.

[0124] Therefore, for the position detection device 1 that detects the detection range from 0° to 24°, there is no need to derive the correction terms for the first gain, the correction terms for the first offset, the correction terms for the second gain, and the correction terms for the second offset in such a way as to reduce the error of the rotational position outside the detection range. In other words, the position detection device 1 that detects the detection range from 0° to 24° only needs to derive the correction terms for the first gain, the correction terms for the first offset, the correction terms for the second gain, and the correction terms for the second offset in such a way as to reduce the error of the rotational position within the detection range.

[0125] Therefore, in the present embodiment, correction terms for the first gain and correction terms for the first offset are derived so that the first transformed signal Si approximates an ideal sine wave shape within the angular range of 0° to 24° as the detection range. Further, correction terms for the second gain and correction terms for the second offset are derived so that the second transformed signal Co approximates an ideal cosine wave shape within the angular range of 0° to 24° as the detection range.

[0126] In this way, it is assumed that the first correction term and the second correction term are derived within the angular range detected by the position detection device 1. And it is assumed that the mechanical angle as the rotational angle of the rotating member 20 is obtained using the derived first correction term and second correction term. Then, the relationship between the rotational angle of the rotating member 20 and the electrical angle of the first receiving coil 32 becomes Figure 9 as shown. Specifically, the rotational angle (i.e., mechanical angle) of the rotating member 20 is proportional to the electrical angle of the first receiving coil 32. And regardless of the gap G, the relative relationship between the mechanical angle of the rotating member 20 and the electrical angle of the first receiving coil 32 is substantially the same.

[0127] Accordingly, regardless of the size of the gap G, the rotational angle is as Figure 10 shown, and it is possible to make the error within the angular range of 0° to 24° smaller than the error within an angular range greater than 24°.

[0128] In addition, Figure 10 The solid line A shown represents the error in the rotation angle when the design value of the clearance G during the assembly of the rotating member 20 and the substrate 30 to the rotating shaft 70 is set to 3 mm and the actual clearance G is set to 2 mm. In addition, the solid line B represents the error in the rotation angle when the design value of the clearance G is set to 3 mm and the actual clearance G is set to 2.5 mm. In addition, the solid line C represents the error in the rotation angle when the design value of the clearance G is set to 3 mm and the actual clearance G is set to the design value, i.e., 3 mm. In addition, the solid line D represents the error in the rotation angle when the design value of the clearance G is set to 3 mm and the actual clearance G is set to 3.5 mm. In addition, the solid line E represents the error in the rotation angle when the design value of the clearance G is set to 3 mm and the actual clearance G is set to 4 mm. For the error in the rotation angle, the longer the clearance G, the smaller the amplitude, and the shorter the clearance G, the larger the amplitude.

[0129] However, as Figure 10 shown, the error when the clearance G deviates from the design value is larger than the error when the clearance G is the design value. Here, the design value refers to the size of the clearance G that serves as a reference when assembling the rotating member 20 and the substrate 30 to the rotating shaft 70. Therefore, the error when the size of the clearance G deviates from the reference clearance, i.e., when it is 2 mm, 2.5 mm, 3.5 mm, or 4 mm, is greater than the error when the size of the clearance G is the reference clearance of 3 mm. Thus, the first correction term and the second correction term are derived in such a way that the difference between the error when the clearance G is the design value and the error when the clearance G deviates from the design value becomes smaller respectively.

[0130] Hereinafter, among these clearances G that deviate from the design value, the clearances G of 2 mm and 2.5 mm where the interval between the rotating member 20 and the substrate 30 is smaller than the reference clearance are set as near clearances. In addition, among these clearances G that deviate from the design value, the clearances G of 3.5 mm and 4 mm where the interval between the rotating member 20 and the substrate 30 is larger than the reference clearance are set as far clearances.

[0131] And the reference clearance is set to the center, i.e., 3 mm, between the size of the clearance G that is the farthest from the reference clearance among the near clearances of 2 mm and 2.5 mm and the clearance G that is the farthest from the reference clearance among the far clearances of 3.5 mm and 4 mm.

[0132] And, Figure 10 the error when the clearance G is 3 mm as shown is set as the reference error, and the errors when the clearance G is 2 mm, 2.5 mm, 3.5 mm, and 4 mm respectively are set as off-reference errors.

[0133] Derive the first correction term and the second correction term such that the reference error and the off-reference error for each mechanical angle in the angular range from 0° to 24° approach 0 respectively. The first correction term and the second correction term of the present embodiment are derived based on the reference error so as to reduce the difference between the reference error and each of the four off-reference errors. Specifically, derive the first gain correction term and the first offset correction term such that the absolute value of the value obtained by subtracting each of the four off-reference errors from the reference error for each mechanical angle in the angular range from 0° to 24° becomes smaller. In addition, derive the second gain correction term and the second offset correction term such that the absolute value of the value obtained by subtracting each of the four off-reference errors from the reference error for each mechanical angle in the angular range from 0° to 24° becomes smaller.

[0134] In this way, derive the first correction term and the second correction term so that the difference between the error when the clearance G is the design value and the error when the clearance G deviates from the design value becomes smaller respectively, and obtain the rotation angle of the rotating member 20, that is, the mechanical angle. Then, as Figure 11 shown, whether the clearance G is the design value or the clearance G deviates from the design value, it is possible to reduce the error of each mechanical angle of the rotation angle θ calculated by the position calculation unit 55.

[0135] Explain the reason for deriving the first correction term and the second correction term in such a way that the difference between the error when the clearance G is the design value and the error when the clearance G deviates from the design value becomes smaller respectively.

[0136] As described above, for the magnetic field on the axial direction Da passing through the first receiving coil 32 and the second receiving coil 33, the magnetic flux changes according to the size of the clearance G between the rotating member 20 and the substrate 30. Therefore, the first voltage value V1 generated in the first receiving coil 32 and the second voltage value V2 generated in the second receiving coil 33 change based on the clearance G between the rotating member 20 and the substrate 30. Thus, the amplitudes and offsets of the first conversion signal Si obtained based on the first voltage value V1 and the second conversion signal Co obtained based on the second voltage value V2 change corresponding to the clearance G. And the change in the amplitude and the change in the offset of the first conversion signal Si and the second conversion signal Co respectively become the reasons for causing an error in the rotation angle θ calculated by the position calculation unit 55.

[0137] According to the inventor's specific research, as Figure 12 shown, in the offsets of the first conversion signal Si and the second conversion signal Co that change corresponding to the clearance G, there are included an offset component that does not depend on the change in amplitude and an offset component that changes corresponding to the change in amplitude. Specifically, it is known that the change amount of the offset component that does not depend on the change in amplitude is less than that of the offset component that changes corresponding to the change in amplitude along with the change in the clearance G. For example, inFigure 12 In one example shown, the offset component that does not depend on the change in amplitude has almost the same magnitude regardless of the size of the gap G and is substantially constant. Such an offset component that does not depend on the change in amplitude is caused, for example, by a wiring pattern different from the transmission coil 31, the first reception coil 32, and the second reception coil 33 in the substrate 30 having a coil component or the like.

[0138] In contrast, the smaller the gap G, the larger the offset component that changes corresponding to the change in amplitude, and the larger the gap G, the smaller the offset component that changes corresponding to the change in amplitude. In other words, the offset component that changes corresponding to the change in amplitude becomes larger when the gap G is a near-gap than when the gap G is a far-gap. In the present embodiment, the offset component that changes corresponding to the change in amplitude decreases proportionally as the gap G becomes smaller.

[0139] In addition, in Figure 12 , the offset component that does not depend on the change in amplitude is represented in a hollow manner, and the offset component that changes corresponding to the change in amplitude is represented in a shaded manner. Hereinafter, in the offset of the first conversion signal Si, the offset component that does not depend on the change in the amplitude of the first conversion signal Si is also referred to as the first fixed offset, and the offset component whose magnitude changes corresponding to the change in the amplitude of the first conversion signal Si is referred to as the first variable offset. In addition, in the offset of the second conversion signal Co, the offset component that does not depend on the change in the amplitude of the second conversion signal Co is also referred to as the second fixed offset, and the offset component whose magnitude changes corresponding to the change in the amplitude of the second conversion signal Co is referred to as the second variable offset.

[0140] In addition, although the magnitude of the first fixed offset hardly changes according to the change in the amplitude of the first conversion signal Si, it does not necessarily mean that it is constant. In addition, although the magnitude of the second fixed offset hardly changes according to the change in the amplitude of the second conversion signal Co, it does not necessarily mean that it is constant.

[0141] In addition, the amplitudes of the first conversion signal Si and the second conversion signal Co are larger when the gap G is smaller and smaller when the gap G is larger. Therefore, the larger the gap G, the greater the influence of the change in the offset of the first conversion signal Si and the second conversion signal Co.

[0142] In addition, as described above, the first conversion signal Si is a sine wave shape with frequency components superimposed thereon. The second conversion signal Co is a cosine wave shape with frequency components superimposed thereon. According to further specific research by the inventor, among the frequency components superimposed on the first conversion signal Si and the second conversion signal Co, in addition to the 0th component and the 1st component, higher-order components are also included, but these components included in the frequency components differ corresponding to the gap G. Specifically, it is known that for the higher-order components superimposed on the first conversion signal Si and the second conversion signal Co, the smaller the gap G, the more the frequency components of the higher-order components, and the larger the gap G, the fewer the frequency components of the higher-order components.

[0143] For example, when the gap G is a near-gap, the higher-order components superimposed on the first conversion signal Si and the second conversion signal Co have more higher-order components of the second order or higher compared to the case where the gap G is a far-gap. In addition, when the gap G is a near-gap, the higher-order components superimposed on the first conversion signal Si and the second conversion signal Co have fewer components of the first order or lower, and the smaller the size of the gap G, the fewer the 0th components.

[0144] In contrast, when the gap G is a far-gap, the higher-order components superimposed on the first conversion signal Si and the second conversion signal Co contain more 0th components. In addition, when the gap G is a far-gap, the higher-order components superimposed on the first conversion signal Si and the second conversion signal Co contain more 0th components compared to other components. The 0th component superimposed on the first conversion signal Si is generated due to the first quantitative offset and the first variable offset. In addition, the 0th component superimposed on the second conversion signal Co is generated due to the second quantitative offset and the second variable offset.

[0145] The inventor discovered such characteristics by varying the set value of the gap G between the rotating member 20 and the substrate 30 and performing FFT analysis on the first conversion signal Si and the second conversion signal Co for each set value of the gap G.

[0146] In addition, the position calculation unit 55 calculates the rotation angle θ by using the first conversion signal Si and the second conversion signal Co to calculate the arctangent function and performing an arctangent transformation. Therefore, the frequency components superimposed on the first conversion signal Si and the second conversion signal Co are the cause of errors in the calculation result of the rotation angle θ calculated by the position calculation unit 55. And the frequency components superimposed on the first conversion signal Si and the second conversion signal Co, by being subjected to the arctangent transformation, have their respective orders increased by 1 compared to before the arctangent transformation.

[0147] For example, the second-order components superimposed on the first conversion signal Si and the second conversion signal Co become third-order components through an arctangent transformation. In addition, the zero-order components superimposed on the first conversion signal Si and the second conversion signal Co become first-order components through an arctangent transformation.

[0148] Therefore, when the gap G is a near-gap case where it contains more high-order components of the second order or higher than components of the first order or lower, the rotation angle θ calculated by performing an arctangent transformation on the first conversion signal Si and the second conversion signal Co includes errors of high-order components of the third order or higher. However, the first conversion signal Si and the second conversion signal Co in the case where the gap G is a near-gap have fewer components of the first order or lower than in the case where the gap G is a far-gap. Therefore, the error in the rotation angle θ in the case where the gap G is a near-gap hardly includes components of the second order or lower compared to the case where the gap G is a far-gap. In this case, in the rotation angle θ in the angular range from 0° to 24° calculated by the position calculation unit 55, errors of high-order components of the third order or higher are superimposed over the entire angular range.

[0149] In contrast, when the gap G is a far-gap case where it contains more zero-order components than other components, the error of the first-order component is more included in the rotation angle θ calculated by performing an arctangent transformation on the first conversion signal Si and the second conversion signal Co. In this case, in the rotation angle θ in the angular range from 0° to 24° calculated by the position calculation unit 55, an error that increases proportionally as the calculated rotation angle θ increases is superimposed.

[0150] Thus, when frequency components are superimposed on the first conversion signal Si and the second conversion signal Co, the zero-order component has a greater impact on the calculation result of the rotation angle θ compared to the frequency components of the high-order components. Moreover, the zero-order component superimposed on the first conversion signal Si is caused by the first fixed offset and the first variable offset. In addition, the zero-order component superimposed on the second conversion signal Co is caused by the second fixed offset and the second variable offset. Therefore, the greater the gap G, the greater the influence of the offset components of these first conversion signal Si and second conversion signal Co respectively.

[0151] In the present embodiment, the GOP correction unit 54 derives a first correction term and a second correction term in such a manner that the difference between the error when the gap G is the design value and the error when the gap G is a far gap becomes smaller. Specifically, the GOP correction unit 54 derives a first offset correction term and a second offset correction term such that the primary component obtained by performing an arctangent transform on the first conversion signal Si and the second conversion signal Co by the position calculation unit 55 when the gap G is a far gap is close to the primary component obtained by performing an arctangent transform on the first conversion signal Si and the second conversion signal Co by the position calculation unit 55 when the gap G is a near gap.

[0152] Furthermore, the GOP correction unit 54 derives the first offset correction term by adjusting the first fixed offset such that the relationship between the change amount of the amplitude of the first conversion signal Si and the change amount of the offset of the first conversion signal Si obtained based on the change amount of the amplitude of the first conversion signal Si becomes a proportional relationship. In other words, the first offset correction term is derived such that the offset of the first conversion signal Si after adjusting the first fixed offset linearly decreases in proportion to the decrease in the amplitude of the first conversion signal Si.

[0153] For example, as in the present embodiment, when the first variable offset linearly decreases in proportion to the decrease in the amplitude of the first conversion signal Si, the GOP correction unit 54 may also derive a first offset correction term that can remove the amount of the first fixed offset in the offset. Thereby, the relationship between the change amount of the amplitude of the first conversion signal Si and the change amount of the offset of the first conversion signal Si obtained based on the change amount of the amplitude of the first conversion signal Si can be set as a proportional relationship with a negative proportional constant. And thereby, in the first conversion signal Si after the offset adjustment by the GOP correction unit 54, an offset that changes in proportion to the change amount of the amplitude of the first conversion signal Si remains.

[0154] In addition, the GOP correction unit 54 derives the second offset correction term by adjusting the second fixed offset such that the relationship between the change amount of the amplitude of the second conversion signal Co and the change amount of the offset of the second conversion signal Co obtained based on the change amount of the amplitude of the second conversion signal Co is a proportional relationship. In other words, the second offset correction term is derived such that the offset of the second conversion signal Co after adjusting the second fixed offset linearly decreases in proportion to the decrease in the amplitude of the second conversion signal Co.

[0155] For example, as in the present embodiment, when the second variable offset linearly decreases in proportion to the decrease in the amplitude of the second conversion signal Co, the GOP correction unit 54 may also derive a correction term for the second offset that can remove the amount of the second quantization offset in the offset. Thereby, the relationship between the change amount of the amplitude of the second conversion signal Co and the change amount of the offset of the second conversion signal Co obtained based on the change amount of the amplitude of the second conversion signal Co can be made a proportional relationship with a negative proportionality constant. And thereby, in the second conversion signal Co after the offset adjustment by the GOP correction unit 54, there remains an offset that changes in proportion to the change amount of the amplitude of the second conversion signal Co.

[0156] In this way, the offset that changes in proportion to the change amount of the amplitude of the first conversion signal Si remaining in the first conversion signal Si becomes the cause of the generation of the DC component in the frequency components superimposed on the first conversion signal Si. In addition, the offset that changes in proportion to the change amount of the amplitude of the second conversion signal Co remaining in the second conversion signal Co becomes the cause of the generation of the DC component in the frequency components superimposed on the second conversion signal Co. And these offsets remaining in the first conversion signal Si and the second conversion signal Co after the offset adjustment become the first-order components through the arctangent transformation using the first conversion signal Si and the second conversion signal Co.

[0157] The first-order component remaining in the rotation angle θ obtained by the arctangent transformation using the offset-adjusted first conversion signal Si and second conversion signal Co can be removed by the process performed by the section correction unit 56 described later.

[0158] By deriving the first correction term and the second correction term as described above, the difference between the error when the gap G is the design value and the error when the gap G is the near-gap can be made smaller. In addition, the influence of the offset component that does not depend on the change in amplitude can be reduced.

[0159] In addition, the method of deriving the first correction term and the second correction term so that the reference error and the out-of-reference error are respectively close to 0 is not limited to the above description.

[0160] For example, the method of deriving the first correction term and the second correction term may be to derive them in such a way that the sum of the absolute value of the reference error and the absolute value of the out-of-reference error for each mechanical angle becomes the minimum value. In addition, the method of deriving the first correction term and the second correction term may be to derive them using the least squares method. According to the derivation method based on the least squares method, even when noise is superimposed on the first voltage value V1 and the second voltage value V2, the first correction term and the second correction term that can reduce the influence of the noise can be derived.

[0161] Further, the GOP correction unit 54 corrects the first transform signal Si and the second transform signal Co using the first correction term and the second correction term derived in this way, so that the error when the gap G is the design value and the error when the gap G deviates from the design value are each close to 0. Further, the GOP correction unit 54 derives tanθ using Equation 1. The GOP correction unit 54 transmits the information of the derived tanθ to the position calculation unit 55.

[0162] In addition, in an example shown in the present embodiment, as Figure 11 shown, in the range of the mechanical angle from 0° to 24°, when it is 0°, 12°, and 21°, the reference error is 0. Further, in the range of the mechanical angle from 0° to 12° and from 21° to 24°, the reference error is on the positive side larger than 0, and in the range of the mechanical angle from 12° to 21°, the reference error is on the negative side smaller than 0. That is, in the range of the mechanical angle from 0° to 24°, the reference error has a wave shape that alternately changes to the positive side and the negative side.

[0163] In addition, for the reference external error in the case where the gap G is the near-gap of 2 mm and 2.5 mm, in the range of the mechanical angle from approximately 2° to approximately 10°, the value of this error is larger than the reference error in the case of comparison at the same mechanical angle. In addition, for the reference external error in the case where the gap G is the near-gap of 2 mm and 2.5 mm, in the range of the mechanical angle from 0° to approximately 2° and from 10° to approximately 24°, the value of this error is smaller than the reference error in the case of comparison at the same mechanical angle.

[0164] In this way, the reference external error in the case where the gap G is the near-gap, like the reference error, has a wave shape change in the range of the mechanical angle from 0° to 24°, and its value changes crossing the reference error. And, the reference external error having a wave shape change in the case where the gap G is the near-gap changes along with the change in the value of the reference error. That is, the reference external error in the case where the gap G is the near-gap is on the positive side in the range substantially the same as the range of the mechanical angle where the reference error is on the positive side. And, the reference external error in the case where the gap G is the near-gap is on the negative side in the range substantially the same as the range of the mechanical angle where the reference error is on the negative side.

[0165] In addition, for the reference external error when the gap G is 3.5 mm and 4 mm as the far gap, in the mechanical angle range from approximately 0° to approximately 13° and from 22° to approximately 24°, the value of this error is smaller than the reference error when compared at the same mechanical angle. In addition, for the reference external error when the gap G is 3.5 mm and 4 mm as the far gap, in the mechanical angle range from 13° to approximately 22°, the value of this error is larger than the reference error when compared at the same mechanical angle.

[0166] Thus, the reference external error when the gap G is the far gap, similar to the reference error, varies in a wave shape within the mechanical angle range from 0° to 24°, and its value changes crossing the reference error. And the reference external error that varies in a wave shape when the gap G is the far gap changes along with the change in the value of the reference error. That is, for the reference external error when the gap G is the far gap, within a range approximately the same as the range of the mechanical angle on the positive side of the reference error, its value is on the positive side. And for the reference external error when the gap G is the far gap, within a range approximately the same as the range of the mechanical angle on the negative side of the reference error, its value is on the negative side.

[0167] The position calculation unit 55 uses the information of tanθ derived by the GOP correction unit 54 to calculate the position of the detection object before correction (i.e., the position of the detection object before correction) of the rotating member 20, namely the rotation angle θ. In the present embodiment, the position calculation unit 55 uses tanθ derived from Equation 1 to calculate the rotation angle θ of the rotating member 20.

[0168] The interval correction unit 56 is connected to the position calculation unit 55 and the output unit 57, and outputs the corrected rotation angle θa obtained by correcting the rotation angle θ, which is the position of the detection object before correction calculated by the position calculation unit 55, to the output unit 57. In the present embodiment, the interval correction unit 56 performs interval correction using the error of the calculated rotation angle θ and the correction function shown in the following Equation 2, and calculates the corrected rotation angle θa.

[0169] (Equation 2)

[0170] y = αx + β…(Equation 2)

[0171] In Equation 2, y represents the corrected rotation angle θa as the output value, and x represents the rotation angle θ calculated by the position calculation unit 55. In addition, α in Equation 2 represents the tilt correction value, and β represents the offset correction value.

[0172] Further, the interval correction unit 56 derives an inclination correction value α and an offset correction value β for each of a plurality of intervals (i.e., rotation angle ranges) such that the reference error approaches 0 in each of the preset intervals. In addition, in the example of the present embodiment, as Figure 13 shown, the angular range from 0° to 24° as the detection range is divided into seven intervals.

[0173] The correction function shown in Equation 2 is a function representing the relationship between the mechanical angle and the rotation angle θ in each of the seven intervals, and is obtained based on the rotation angle θ calculated by the position calculation unit 55. The interval correction unit 56 derives an inclination correction value α and an offset correction value β for each of the seven intervals. Further, the interval correction unit 56 corrects the rotation angle θ for each of the seven intervals using the rotation angle θ calculated by the position calculation unit 55, the derived inclination correction value α, and the offset correction value β, and calculates a corrected rotation angle θa.

[0174] Thus, as Figure 13 shown, when the gap G is 3 mm as the design value, compared with the reference error of the rotation angle θ shown in Figure 13 the reference error of the corrected rotation angle θa can be made to approach 0.

[0175] In addition, the interval correction unit 56 calculates the corrected rotation angle θa based on the rotation angle θ obtained by the position calculation unit 55 after performing an arctangent transform on the first transform signal Si and the second transform signal Co. Further, in the first transform signal Si and the second transform signal Co used to obtain the rotation angle θ, as described above, a frequency component of the zero-th order is superimposed. The zero-th order component superimposed on the first transform signal Si and the second transform signal Co is a cause of an increase in the error included in the rotation angle θ compared with the frequency component of the higher order components. This is because when the arctangent transform is performed on the first transform signal Si and the second transform signal Co to obtain the rotation angle θ, the zero-th order component superimposed on the first transform signal Si and the second transform signal Co becomes a first-order component.

[0176] Further, in the first transform signal Si corrected by the GOP correction unit 54, an offset that varies corresponding to the change amount of the amplitude of the first transform signal Si, which is a cause of the zero-th order component, is included. In addition, in the second transform signal Co corrected by the GOP correction unit 54, an offset that varies corresponding to the change amount of the amplitude of the second transform signal Co, which is a cause of the zero-th order component, is included.

[0177] Therefore, the interval correction unit 56 of the present embodiment performs interval correction using the correction function shown in Equation 2 to remove the first-order component included in the rotation angle θ obtained by performing arctangent transformation using the first transformation signal Si and the second transformation signal Co. In other words, the interval correction unit 56 performs interval correction to remove the remaining first-order component in the rotation angle θ obtained by performing arctangent transformation using the first transformation signal Si and the second transformation signal Co whose offsets have been adjusted by the GOP correction unit 54.

[0178] In addition, the interval correction unit 56 may derive the tilt correction value α and the offset correction value β for each of fewer than 7 intervals or more than 7 intervals.

[0179] Furthermore, it is possible to reduce the difference between the maximum error and the minimum error among all the off-reference errors. In an example shown in the present embodiment, the off-reference error with the largest error among all the off-reference errors is the case where the gap G is 2 mm as the near gap and the mechanical angle is 8°. In addition, the off-reference error with the smallest error among all the off-reference errors is the case where the gap G is 2 mm as the near gap and the mechanical angle is 16°. And it is possible to make the difference between the maximum error and the minimum error be 0.18 deg.

[0180] Here, as described above, for the off-reference errors of the gap G being 2 mm, 2.5 mm, 3.5 mm, and 4 mm respectively, similar to the reference error, in the angular range of the mechanical angle from 0° to 24°, their values change in a wave shape. These off-reference errors are positive in a range substantially the same as the range of the mechanical angle on the positive side of the reference error, and are negative in a range substantially the same as the range of the mechanical angle on the negative side of the reference error.

[0181] Therefore, due to the assembly error of the rotating member 20 and the substrate 30, etc., even when the gap G deviates from the design value, it is possible to make the off-reference error approach 0 by using the tilt correction value α and the offset correction value β derived in such a way that the reference error approaches 0.

[0182] For example, in the range where the mechanical angle is from 0° to 12° and from 21° to 24°, the reference error is on the positive side larger than 0. Therefore, by using the tilt correction value α and the offset correction value β derived in such a way that the reference error approaches 0, the reference errors in the range where the mechanical angle is from 0° to 12° and from 21° to 24° are reduced and approach 0. That is, the reference error is corrected to the negative side in the range where the mechanical angle is from 0° to 12° and from 21° to 24°.

[0183] Further, by correcting the off-reference errors using these tilt correction values α and offset correction values β, the off-reference errors are corrected to the negative side within the range of the mechanical angle on the positive side of the reference error. Therefore, by correcting the off-reference errors on the positive side within the range of the mechanical angle approximately the same as the reference error using the tilt correction values α and offset correction values β, they can be made close to 0.

[0184] In addition, within the range where the mechanical angle is from 12° to 21°, the reference error is on the negative side smaller than 0. Therefore, by using the tilt correction values α and offset correction values β derived in such a way that the reference error is close to 0, the reference error within the range where the mechanical angle is from 12° to 21° is made larger and close to 0. That is, the reference error is corrected to the positive side within the range where the mechanical angle is from 12° to 21°.

[0185] Further, by correcting the off-reference errors using these tilt correction values α and offset correction values β, the off-reference errors are corrected to the positive side within the range of the mechanical angle on the negative side of the reference error. Therefore, by correcting the off-reference errors on the negative side within the range of the mechanical angle approximately the same as the reference error using the tilt correction values α and offset correction values β, they can be made close to 0.

[0186] In this way, when calculating the corrected rotation angle θa using Equation 2, the off-reference errors can be made close to 0 without deriving the tilt correction values α and offset correction values β for each gap G.

[0187] As described above, the signal processing unit 50 of the present embodiment includes: a GOP correction unit 54 that corrects the first transformed signal Si and the second transformed signal Co; and a position calculation unit 55 that calculates the rotation angle θ before correction based on the first transformed signal Si and the second transformed signal Co corrected by the GOP correction unit 54. Further, the signal processing unit 50 has an interval correction unit 56 that corrects the rotation angle θ for each of the seven intervals to calculate the corrected rotation angle θa. The GOP correction unit 54 corrects the first transformed signal Si and the second transformed signal Co so that the errors of the rotation angle θ when the rotating member 20 and the substrate 30 are arranged with the gap G being 2 mm, 2.5 mm, 3 mm, 3.5 mm, and 4 mm are respectively close to 0. The interval correction unit 56 derives the tilt correction values α and offset correction values β in the correction function for each of the seven intervals.

[0188] Thereby, when the interval between the rotating member 20 and the substrate 30 is configured as the gap G of the design value, by correcting the rotation angle θ to the corrected rotation angle θa, the detection error can be reduced compared with the case where no correction is performed. That is, the detection accuracy of the position detection device 1 can be improved.

[0189] In addition, even when the gap between the rotating member 20 and the substrate 30 is configured as a gap G that deviates from the design value, by performing correction using the tilt correction value α and the offset correction value β in the case of the gap G configured as the design value, the detection error can be reduced.

[0190] In addition, according to the above-described embodiment, the following effects can be obtained.

[0191] (1) In the above-described embodiment, the rotating member 20 is a rotating body and is configured to be able to rotate within a rotation range of from 0° to 24°, which is smaller than from 0° to 360°. The first receiving coil 32 outputs a first voltage value V1 corresponding to the rotation angle θ of the rotating member 20 when the rotating member 20 rotates within the rotation range of from 0° to 24°. The second receiving coil 33 outputs a second voltage value V2 corresponding to the rotation angle θ of the rotating member 20 when the rotating member 20 rotates within the rotation range of from 0° to 24°. The position calculation unit 55 calculates the rotation angle θ of the rotating member 20 that rotates within the rotation range of from 0° to 24° based on the first voltage value V1 and the second voltage value V2 corresponding to the rotation angle θ of the rotating member 20. The GOP correction unit 54 corrects the first conversion signal Si and the second conversion signal Co so that the error of the rotation angle θ within the rotation range of from 0° to 24° calculated by the position calculation unit 55 approaches 0.

[0192] Accordingly, since the angle range in which the error of the rotation angle θ approaches 0 is limited, it is easier to make the absolute value of the error at each angle within the rotation range smaller than in the case where the angle range in which the error approaches 0 is not limited.

[0193] (2) In the above-described embodiment, the reference gap is set at the center between 2 mm, which is the farthest from the reference gap among the 2 near gaps, i.e., 2 mm and 2.5 mm, and 4 mm, which is the farthest from the reference gap among the 2 far gaps, i.e., 3.5 mm and 4 mm.

[0194] Accordingly, it is easier to reduce the error of the rotation angle θ compared to the case where the reference gap is not set in this way. That is, it is easy to improve the detection accuracy of the position detection device 1.

[0195] (First Modification Example of the First Embodiment)

[0196] In the above-described first embodiment, an example has been described in which the position detection device 1 calculates the rotational position of the rotating member 20 that rotates within an angular range of 0° to 24°, which is smaller than 0° to 360°. However, the rotational position calculated by the position detection device 1 is not limited thereto. For example, the position detection device 1 may also calculate the rotational position of the rotating member 20 that rotates within an angular range smaller than 0° to 360° and different from 0° to 24°. In addition, the position detection device 1 may also calculate the rotational position of the rotating member 20 that rotates within the angular range of 0° to 360°. Further, for the detection object calculated by the position detection device 1, in the case of a rotating body, it is not limited to the pedal.

[0197] (Second modification of the first embodiment)

[0198] In the above-described first embodiment, an example has been described in which the GOP correction unit 54 derives the first correction term and the second correction term based on the reference error to reduce the difference between the reference error and each of the four off-reference errors. However, it is not limited thereto.

[0199] For example, it is assumed that the central value among the five errors of the reference error and the four off-reference errors is set as the reference value. And the first correction term and the second correction term may be derived in such a way as to reduce the difference between the reference value and each of the reference error and the four off-reference errors.

[0200] (Third modification of the first embodiment)

[0201] In the above-described first embodiment, an example has been described in which the first correction term and the second correction term are derived by an external device different from the position detection device 1. However, it is not limited thereto. For example, the position detection device 1 may also derive the first correction term and the second correction term by the above-described derivation method. Specifically, it may be derived by the constituent device (for example, the GOP correction unit 54) of the signal processing unit 50 in the position detection device 1. In addition, the position detection device 1 may also be configured with a correction term derivation unit for deriving the first correction term and the second correction term.

[0202] (Fourth modification of the first embodiment)

[0203] In the above-described first embodiment, an example has been described in which the GOP correction unit 54 corrects the first conversion signal Si and the second conversion signal Co respectively, and uses the corrected first conversion signal Si and second conversion signal Co and Equation 1 to derive tanθ. However, it is not limited thereto. For example, it may also be a configuration in which the position calculation unit 55 uses the corrected first conversion signal Si and second conversion signal Co by the GOP correction unit 54 and Equation 1 to derive tanθ.

[0204] In the case of such a configuration, as Figure 14As shown, the GOP correction unit 54 corrects the first transform signal Si and the second transform signal Co using at least one of the correction terms for gain, offset, and phase. Then, the information of the corrected first transform signal Si and second transform signal Co is output to the position calculation unit 55.

[0205] When the position calculation unit 55 receives the information of the corrected first transform signal Si and second transform signal Co from the GOP correction unit 54, it can calculate tanθ using Equation 1 and use the calculated tanθ to calculate the rotation angle θ of the rotating member 20.

[0206] (Second Embodiment)

[0207] Next, with reference to Figure 15 and Figure 16 the second embodiment will be described. In this embodiment, the pattern shapes of the first receiving coil 32 and the second receiving coil 33 are different from those of the first embodiment. Other than this, it is the same as the first embodiment. Therefore, in this embodiment, mainly the parts different from the first embodiment will be described, and the description of the parts the same as the first embodiment may be omitted sometimes.

[0208] As Figure 15 shown, the first receiving coil 32 and the second receiving coil 33 of this embodiment are formed in an annular shape extending along the circumferential direction Dc of the substrate 30.

[0209] In addition, when observed in the direction along the normal direction, the first receiving coil 32 and the second receiving coil 33 are arranged inside the transmitting coil 31. In addition, the first receiving coil 32 and the second receiving coil 33 are configured by being appropriately connected to different wiring layers via via holes 34 in such a way that they do not interfere with each other (i.e., do not overlap in the same layer).

[0210] The first receiving coil 32 is formed to depict a pattern shape of a sine curve in a closed-loop sine wave shape. And the first receiving coil 32 is configured by connecting adjacent two wiring layers in the sequentially stacked wiring layers with via holes 34.

[0211] The second receiving coil 33 is formed to depict a pattern shape of a cosine curve with a phase different from that of the sine curve in a closed-loop cosine wave shape. And the second receiving coil 33 is configured by connecting adjacent two wiring layers in the sequentially stacked wiring layers with via holes 34.

[0212] Regarding Figure 15 the display of the first receiving coil 32 and the second receiving coil 33, for easy understanding, the first receiving coil 32 and the second receiving coil 33 formed across multiple stacked wiring layers are all shown with solid lines.

[0213] In addition, the first receiving coil 32 can also be formed into a pattern shape that depicts a cosine curve in a manner that forms a closed-loop cosine wave. In this case, the second receiving coil 33 is formed into a pattern shape that depicts a sine curve with a phase different from that of the cosine curve in a manner that forms a closed-loop sine wave.

[0214] In addition, as Figure 16 shown, the four targets 22 to 25 of the rotating member 20 of the present embodiment are in a fan shape in which the amplitude in the circumferential direction Dc increases as it gets closer to the outer side in the radial direction Dr. Therefore, one end portion and the other end portion of each of the four targets 22 to 25 in the circumferential direction Dc extend in a straight line along the radial direction Dr when viewed in the direction along the axial direction Da.

[0215] According to the present embodiment, when viewed in the direction along the normal direction, the first receiving coil 32 and the second receiving coil 33 are in a pattern shape that depicts a sine curve or a cosine curve. Therefore, the first receiving coil 32 outputs a first voltage value V1 in a sine wave form corresponding to the rotational position of the rotating member 20. In addition, the second receiving coil 33 outputs a second voltage value V2 in a cosine wave form corresponding to the rotational position of the rotating member 20.

[0216] Except for the parts described above, the present embodiment is the same as the first embodiment. And in the present embodiment, the effects achieved by the structure common to the first embodiment can be obtained in the same manner as in the first embodiment.

[0217] (Third Embodiment)

[0218] Next, refer to Figure 17 and Figure 18 to describe the third embodiment. In the present embodiment, the shape and structure of the position detection device 1 are different from those of the first embodiment. Other than this, it is the same as the first embodiment. Therefore, in the present embodiment, mainly the parts different from the first embodiment will be described, and the description of the parts the same as the first embodiment may be omitted sometimes.

[0219] The position detection device 1 of the present embodiment is configured to be able to detect the position in the traveling direction of the detection object. The detection object is, for example, a movable part 100 mounted on a vehicle. The position detection device 1 detects the position of the movable part 100 as the detection object that moves along the traveling direction.

[0220] The movable part 100 of the present embodiment moves linearly forward and reciprocates within a specified range along the traveling direction. As Figure 17As shown, the movable part 100 has a plurality of magnets 110, 120, and 130. The plurality of magnets 110, 120, and 130 are arranged apart from each other along the stroke direction. The plurality of magnets 110, 120, and 130 each have magnetic pole faces 111, 121, and 131 with polarities having N poles or S poles. Also, the plurality of magnets 110, 120, and 130 are arranged such that the mutually adjacent magnetic pole faces 111, 121, and 131 are opposite poles with N poles and S poles being opposite.

[0221] The position detection device 1 has a housing part 10 at the front end on the movable part 100 side, and the detection part 60 described later is provided in the housing part 10. Also, the position detection device 1 provides a prescribed gap between the magnetic pole faces 111, 121, and 131 of each of the plurality of magnets 110, 120, and 130 and the housing part 10. In other words, the housing part 10 is arranged to face the movable part 100 in a state of being separated from each of the plurality of magnets 110, 120, and 130. Further, the housing part 10 is arranged such that the prescribed gap between each of the magnetic pole faces 111, 121, and 131 and the housing part 10 is constant. The gap G in the present embodiment corresponds to the distance between each of the magnetic pole faces 111, 121, and 131 and the housing part 10.

[0222] In addition, the position detection device 1 in the present embodiment employs a magnetic detection method using Figure 18 the magnetoresistive elements 61 and 62 shown. When affected by a magnetic field from the outside, the resistance values of the magnetoresistive elements 61 and 62 change, and the magnetoresistive elements 61 and 62 are provided inside the housing part 10. The magnetoresistive elements 61 and 62 can be, for example, anisotropic magnetoresistive elements, i.e., AMR (Anisotropic Magneto Resistive) elements, giant magnetoresistive elements, i.e., GMR (Giant Magneto Resistive) elements, tunnel magnetoresistive elements, i.e., TMR (Tunnel Magneto Resistive) elements, etc.

[0223] Alternatively, a Hall element can be used instead of the magnetoresistive elements 61 and 62, and the position detection device 1 can be used for a magnetic detection method using a Hall element.

[0224] As Figure 18 shown, the detection part 60 has two magnetoresistive elements 61 and 62 that function as magnetic detection parts. The two magnetoresistive elements 61 and 62 obtain the change in the resistance value when affected by a magnetic field as a voltage value. Hereinafter, one of the two magnetoresistive elements 61 and 62 is referred to as the first magnetic detection part 61, and the other is referred to as the second magnetic detection part 62.

[0225] The first magnetic detection unit 61 outputs a first voltage value V1 in a sine wave form corresponding to the position of the movable part 100. The second magnetic detection unit 62 outputs a second voltage value V2 in a cosine wave form corresponding to the position of the movable part 100. Therefore, in the present embodiment, the detection unit 60 functions as a signal output unit, and outputs a first signal in a sine wave form and a second signal in a cosine wave form corresponding to the position of the movable part 100 as the detection object. In addition, the housing part 10 functions as a configuration part.

[0226] Except for the parts described above, the present embodiment is the same as the first embodiment. And, in the present embodiment, the effects achieved by the structures common to the first embodiment can be obtained in the same manner as in the first embodiment.

[0227] (Fourth Embodiment)

[0228] Next, with reference to Figure 19 and Figure 20 the fourth embodiment will be described. In the present embodiment, the derivation methods of the first correction term and the second correction term are different from those of the first embodiment. Other than this, it is the same as the first embodiment. Therefore, in the present embodiment, the parts different from the first embodiment will be mainly described, and the description of the parts the same as the first embodiment may be omitted sometimes.

[0229] In the present embodiment, the first correction term and the second correction term are derived so that the error when the gap G is the design value in the angular range from 0° to 24° becomes the minimum.

[0230] Specifically, a first gain correction term, a first offset correction term, a second gain correction term, and a second offset correction term are derived to make the reference error for each mechanical angle in the angular range from 0° to 24° approach 0. At this time, in the present embodiment, the first gain correction term, the first offset correction term, the second gain correction term, and the second offset correction term are derived without considering the reference error outside each mechanical angle in the angular range from 0° to 24°.

[0231] Thus, as Figure 19 shown, the error for each mechanical angle of the rotation angle θ when the gap G is the design value can be made smaller. In addition, by using the first correction term and the second correction term derived in such a way that the error for each mechanical angle of the rotation angle θ when the gap G is the design value is made smaller, the error for each mechanical angle of the rotation angle θ when the gap G deviates from the design value can also be made smaller.

[0232] In addition, as Figure 19 shown, the reference error becomes a wave shape that alternately changes to the positive side and the negative side in the angular range where the mechanical angle is from 0° to 24°.

[0233] Moreover, with respect to the reference external error in the case where the gap G is a near-gap, i.e., 2 mm and 2.5 mm, similar to the reference error, it varies in a wave shape, and its value varies along with the change in the value of the reference error. In addition, within the entire detection range where the mechanical angle is from 0° to 24°, the value of its error is smaller than the reference error in the case of comparison at the same mechanical angle. Therefore, with respect to the reference external error in the case of a near-gap, its value varies without crossing the reference error.

[0234] Furthermore, with respect to the reference external error in the case where the gap G is a far-gap, i.e., 3.5 mm and 4 mm, similar to the reference error, it varies in a wave shape, and its value varies along with the change in the value of the reference error. In addition, within the entire detection range where the mechanical angle is from 0° to 24°, the value of its error is larger than the reference error in the case of comparison at the same mechanical angle. Therefore, with respect to the reference external error in the case of a far-gap, its value varies without crossing the reference error.

[0235] And, the GOP correction unit 54 corrects the first conversion signal Si and the second conversion signal Co using the first gain correction term, the first offset correction term, the second gain correction term, and the second offset correction term derived in this way. And, the GOP correction unit 54 uses Equation 1 to derive tanθ. The GOP correction unit 54 transmits the information of the derived tanθ to the position calculation unit 55.

[0236] The position calculation unit 55 calculates the rotation angle θ of the rotating member 20 before correction using the information of tanθ derived by the GOP correction unit 54. And, the interval correction unit 56 performs interval correction using the rotation angle θ before correction calculated by the position calculation unit 55 and Equation 2 described in the first embodiment, and calculates the corrected rotation angle θa.

[0237] In addition, similar to the first embodiment, the interval correction unit 56 derives an inclination correction value α and an offset correction value β for each of the 7 intervals within the angular range from 0° to 24° as the detection range, so as to make the reference error close to 0. And, the interval correction unit 56 calculates the corrected rotation angle θa using the rotation angle θ calculated by the position calculation unit 55, the derived inclination correction value α, and the offset correction value β.

[0238] Thus, as Figure 20 shown, when the gap G is the design value, i.e., 3 mm, compared with Figure 19 the reference error of the rotation angle θ shown, it is possible to make the reference error of the corrected rotation angle θa close to 0.

[0239] In addition, the difference between the maximum error and the minimum error among all off-reference errors can be reduced. In the present embodiment, among all off-reference errors, the off-reference error with the largest error is the case where the clearance G is 4 mm and the mechanical angle is 18°. Further, among all off-reference errors, the off-reference error with the smallest error is the case where the clearance G is 2 mm and the mechanical angle is 16°. Moreover, the difference between the maximum error and the minimum error can be set to 0.50 deg.

[0240] (Summary of the Fourth Embodiment)

[0241] The fourth embodiment is configured as described above. Therefore, when summarized, it can be said that the following viewpoints are provided.

[0242] (Viewpoint 1)

[0243] A position detection device that detects the position of a detection object (20, 100), comprising: a signal output unit (32, 33, 61, 62) that outputs a first sine-wave signal (V1) corresponding to the position of the detection object and a second signal (V2) corresponding to the position of the detection object, the second signal being a cosine-wave shape with a phase different from that of the first signal; a configuration unit (30, 10) provided with the signal output unit and configured to face the detection object in a state separated from the detection object; and a signal processing unit (50) that calculates the position of the detection object, i.e., the detection object position, when the detection object moves within a specified detection range based on the first signal and the second signal output by the signal output unit; the signal processing unit includes: a signal correction unit (54) that corrects the first signal and the second signal; a position calculation unit (55) that calculates the position of the detection object before correction, i.e., the pre-correction detection object position, based on the first signal and the second signal corrected by the signal correction unit; and an interval correction unit (56) that operates a correction function obtained from the error of the pre-correction detection object position calculated by the position calculation unit and corrects the pre-correction detection object position calculated by the position calculation unit for each of the multiple intervals into which the detection range is divided; when the interval between the detection object and the configuration unit in the facing direction, i.e., the facing direction, is a gap (G), the reference gap is the reference gap, the near gap is the gap in which the interval between the detection object and the configuration unit is smaller than the reference gap, and the far gap is the gap in which the interval between the detection object and the configuration unit is larger than the reference gap, the signal correction unit corrects the first signal and the second signal such that the error of the pre-correction detection object position when the configuration unit is configured with the reference gap approaches 0, so that the errors of the pre-correction detection object positions in the cases of each of the gaps when the configuration unit is configured with at least one of the near gap and the far gap approach 0 respectively; the interval correction unit derives the correction value in the correction function for each of the multiple intervals.

[0244] (Fifth Embodiment)

[0245] Next, refer to Figure 21 to describe the fifth embodiment. In this embodiment, it is different from the first embodiment in that the transmission coil 31 is not formed on the substrate 30. Other than that, it is the same as the first embodiment. Therefore, in this embodiment, mainly the parts different from the first embodiment will be described, and the description of the parts the same as the first embodiment may be omitted sometimes.

[0246] As Figure 21As shown, the substrate 30 of this embodiment is different from that of the first embodiment, and the wiring pattern of the transmission coil 31 is not formed. Also, the first receiving coil 32 and the second receiving coil 33 are mainly in a spiral shape as described in the first embodiment. In this embodiment, the first receiving coil 32 and the second receiving coil 33 formed on the substrate 30 function as inductance elements having a prescribed inductance magnitude when an alternating current is applied from the oscillation unit 51. Additionally, in Figure 21 the illustration of the connection wiring 35 is omitted.

[0247] In the case where the substrate 30 has such a structure without the transmission coil 31, the eddy current generated in the rotating member 20 changes corresponding to the rotational position of the rotating member 20. For example, if the rotating member 20 rotates and the rotational position of the first target 22 facing the first receiving coil 32 and the second receiving coil 33 changes, the eddy current generated in the first target 22 changes.

[0248] Then, the inductances of the first receiving coil 32 and the second receiving coil 33 facing the first target 22 change. Such a change in inductance can be detected by a detection circuit (not shown). The detection circuit is constituted by a resonance circuit including a coil, a capacitor, etc., for example. In other words, the first receiving coil 32 outputs a change in its own inductance that changes corresponding to the rotational position of the rotating member 20. In addition, the second receiving coil 33 outputs a change in its own inductance that changes corresponding to the rotational position of the rotating member 20.

[0249] The changes in the inductances of the first receiving coil 32 and the second receiving coil 33 detected by the detection circuit change periodically corresponding to the rotational position of the rotating member 20. The detection circuit outputs information on the changes in the inductances of the first receiving coil 32 and the second receiving coil 33 detected to the AD conversion unit 53. The information on the change in the inductance of the first receiving coil 32 output by the detection circuit corresponds to the first voltage value V1 of the first embodiment. In addition, the information on the change in the inductance of the second receiving coil 33 output by the detection circuit corresponds to the second voltage value V2 of the first embodiment.

[0250] Except for the parts described above, this embodiment is the same as the first embodiment. Also, in this embodiment, the effects achieved by the structures common to the first embodiment can be obtained in the same manner as in the first embodiment.

[0251] (Other Embodiments)

[0252] Above, representative embodiments of the present disclosure have been described, but the present disclosure is not limited to the above embodiments, and various modifications can be made as follows, for example.

[0253] In the above-described embodiment, an example was described in which the reference gap is 3 mm as a design value, and the gaps G deviating from the design value are 2 mm, 2.5 mm, 3.5 mm, and 4 mm. In addition, an example was described in which the reference gap is 3 mm, which is the center of 2 mm and 4 mm that are the farthest from the reference gap, but it is not limited thereto.

[0254] The reference gap is not limited to 3 mm and can be appropriately changed. In addition, the gap G deviating from the design value may include a gap smaller than 2 mm or may include a gap larger than 4 mm. In addition, among the gaps G deviating from the design value, the near gap may be one or three or more. In addition, among the gaps G deviating from the design value, the far gap may be one or three or more. In addition, the reference gap may also be set to a size that deviates from the center of the size of the farthest from the reference gap among the multiple near gaps and the size of the farthest from the reference gap among the multiple far gaps.

[0255] In the above-described embodiment, an example was described in which the GOP correction unit 54 derives the gain correction term, the offset correction term, and the phase correction term for each of the first transform signal Si and the second transform signal Co, but it is not limited thereto.

[0256] For example, the GOP correction unit 54 only needs to derive at least one of the gain correction term, the offset correction term, and the phase correction term for each of the first transform signal Si and the second transform signal Co. Specifically, the GOP correction unit 54 may also derive, for example, only one of the gain correction term, the offset correction term, and the phase correction term for each of the first transform signal Si and the second transform signal Co. In addition, the GOP correction unit 54 may also derive any two of the gain correction term, the offset correction term, and the phase correction term for each of the first transform signal Si and the second transform signal Co. Furthermore, the GOP correction unit 54 may also derive all of the gain correction term, the offset correction term, and the phase correction term for each of the first transform signal Si and the second transform signal Co.

[0257] In the above-described embodiment, the elements constituting the embodiment are not necessarily essential except in cases where they are specifically indicated as essential and cases where they can be considered obviously essential in principle, etc.

[0258] In the above-described embodiment, when referring to numerical values such as the number, value, quantity, range, etc. of the constituent elements of the embodiment, it is not limited to the specific quantity except in cases where it is specifically indicated as essential and cases where it is clearly limited to a specific quantity in principle, etc.

[0259] In the above-described embodiments, when referring to the shape, positional relationship, etc. of components, etc., it is not limited to such shape, positional relationship, etc., except in cases where it is specifically specified and cases where it is limited to a specific shape, positional relationship, etc. in principle.

[0260] The signal processing circuit 40 and its method of the present disclosure can also be implemented by a dedicated computer provided by a processor and a memory configured to execute one or more functions embodied by a computer program. The signal processing circuit 40 and its method of the present disclosure can also be implemented by a dedicated computer provided by a processor configured by one or more dedicated hardware logic circuits. The signal processing circuit 40 and its method of the present disclosure can also be implemented by one or more dedicated computers constituted by a combination of a processor configured to execute one to more functions and a memory and a processor configured by one or more hardware logic circuits. In addition, the computer program can also be stored as instructions executable by a computer in a computer-readable non-transitory tangible recording medium.

[0261] (Features of the present invention)

[0262] [Technical solution 1]

[0263] A position detection device for detecting the position of a detection object (20, 100), comprising: a signal output unit (32, 33, 61, 62) that outputs a first sine-wave signal (V1) corresponding to the position of the detection object and a second signal (V2) corresponding to the position of the detection object, the second signal being a cosine-wave shape with a phase different from that of the first signal; a configuration unit (30, 10) provided with the signal output unit and configured to face the detection object in a state of being separated from the detection object; and a signal processing unit (50) that calculates the position of the detection object, i.e., the detection object position, when the detection object is displaced within a specified detection range based on the first signal and the second signal; the signal processing unit corrects the first signal and the second signal, calculates the position of the detection object before correction, i.e., the pre-correction detection object position, based on the corrected first signal and second signal, operates a correction function obtained from the error of the calculated pre-correction detection object position, and can correct the pre-correction detection object position calculated for each of the multiple intervals when the detection range is divided into multiple intervals; when the interval between the detection object and the configuration unit in the facing direction, i.e., the facing direction, is a gap (G), the reference gap is the reference gap, the near gap is the gap in which the interval between the detection object and the configuration unit is smaller than the reference gap, and the far gap is the gap in which the interval between the detection object and the configuration unit is larger than the reference gap, the first signal and the second signal are corrected so that the errors of the pre-correction detection object positions when the configuration unit is respectively configured at the reference gap, one or more of the near gaps, and one or more of the far gaps are respectively close to 0, and the correction values in the correction function are derived for each of the multiple intervals.

[0264] [Technical solution 2]

[0265] A position detection device for detecting the position of a detection object (20, 100), comprising: a signal output unit (32, 33, 61, 62) that outputs a first sine-wave signal (V1) corresponding to the position of the detection object and a second signal (V2) corresponding to the position of the detection object, the second signal being a cosine-wave shape with a phase different from that of the first signal; a configuration unit (30, 10) provided with the signal output unit and configured to face the detection object in a state separated from the detection object; and a signal processing unit (50) that calculates the position of the detection object, i.e., the detection object position, when the detection object is displaced within a specified detection range based on the first signal and the second signal. The signal processing unit includes: a signal correction unit (54) that corrects the first signal and the second signal; a position calculation unit (55) that calculates the position of the detection object before correction, i.e., the pre-correction detection object position, based on the first signal and the second signal corrected by the signal correction unit; and an interval correction unit (56) that operates a correction function obtained from an error of the pre-correction detection object position calculated by the position calculation unit and corrects the pre-correction detection object position calculated by the position calculation unit for each of the multiple intervals into which the detection range is divided. When the interval between the detection object and the configuration unit in the facing direction, i.e., the facing direction, is a gap (G), the reference gap is the reference gap, the near gap is the gap in which the interval between the detection object and the configuration unit is smaller than the reference gap, and the far gap is the gap in which the interval between the detection object and the configuration unit is larger than the reference gap, the signal correction unit corrects the first signal and the second signal such that the errors of the pre-correction detection object positions when the configuration unit is respectively configured at the reference gap, one or more of the near gaps, and one or more of the far gaps are respectively close to 0. The interval correction unit derives a correction value in the correction function for each of the multiple intervals.

[0266] [Technical solution 3]

[0267] The position detection device according to Technical solution 2, wherein the detection object is a rotating body that can rotate within a specified rotation range smaller than 0° to 360°. The signal output unit outputs the first signal and the second signal according to the rotation angle of the detection object when the detection object rotates within the specified rotation range. The signal correction unit corrects the first signal and the second signal such that the error of the pre-correction detection object position within the specified rotation range calculated by the position calculation unit is close to 0. The position calculation unit calculates the pre-correction detection object position within the specified rotation range based on the first signal and the second signal corrected by the signal correction unit.

[0268] [Technical Solution 4]

[0269] The position detection device according to Technical Solution 2 or 3, wherein the reference gap is set to the size of the center between the size of the nearest gap farthest from the reference gap among one or more of the nearest gaps and the size of the farthest gap from the reference gap among one or more of the farthest gaps.

[0270] [Technical Solution 5]

[0271] The position detection device according to any one of Technical Solutions 2 to 4, wherein the signal correction unit corrects at least one of the phase, gain, and offset of the first signal and corrects at least one of the phase, gain, and offset of the second signal.

[0272] [Technical Solution 6]

[0273] The position detection device according to Technical Solution 5, wherein the signal correction unit corrects the offset of the first signal and corrects the offset of the second signal in such a manner that the difference between the error of the detected object position before correction when the configuration unit is configured as the reference gap and the error of the detected object position before correction when the configuration unit is configured as the farthest gap approaches 0.

[0274] [Technical Solution 7]

[0275] The position detection device according to Technical Solution 5, wherein the signal processing unit calculates the position of the detected object by performing an operation on the arctangent function based on the first signal and the second signal and performing an arctangent transformation; the signal correction unit corrects the offset of the first signal and corrects the offset of the second signal in such a manner that the primary component obtained by performing an arctangent transformation on the first signal and the second signal by the signal processing unit when the configuration unit is configured as the farthest gap approaches the primary component obtained by performing an arctangent transformation on the first signal and the second signal by the signal processing unit when the configuration unit is configured as the nearest gap.

[0276] [Technical Solution 8]

[0277] The position detection device according to Technical Solution 7, wherein the offset of the first signal includes a first fixed offset and a first variable offset. The first fixed offset is an offset component that does not depend on the change in the amplitude of the first signal, and the first variable offset is an offset component whose magnitude changes according to the change in the amplitude of the first signal. The offset of the second signal includes a second fixed offset and a second variable offset. The second fixed offset is an offset component that does not depend on the change in the amplitude of the second signal, and the second variable offset is an offset component whose magnitude changes according to the change in the amplitude of the second signal. The signal correction unit adjusts the first fixed offset in such a way that the relationship between the change amount of the amplitude of the first signal and the change amount of the offset of the first signal obtained based on the change amount of the amplitude of the first signal is a proportional relationship, and adjusts the second fixed offset in such a way that the relationship between the change amount of the amplitude of the second signal and the change amount of the offset of the second signal obtained based on the change amount of the amplitude of the second signal is a proportional relationship. The interval correction unit corrects the pre-correction detected body position calculated by the position calculation unit for each of the plurality of intervals in such a way as to remove the first-order component included in the position of the detected body calculated by performing an arctangent transformation on the first signal and the second signal.

[0278] [Technical Solution 9]

[0279] The position detection device according to any one of Technical Solutions 1 to 8, wherein the arrangement unit is a substrate. The signal output unit is formed on the substrate and includes a transmitting coil (31) and a first receiving coil (32) and a second receiving coil (33) that are inductively coupled by electromagnetic induction generated by energizing the transmitting coil. The first receiving coil outputs the first signal corresponding to the position of the detected body as a first voltage value, and the first signal is affected by eddy currents flowing in the detected body due to electromagnetic induction from the energized transmitting coil and thus changes. The second receiving coil outputs the second signal corresponding to the position of the detected body as a second voltage value, and the second signal is affected by eddy currents flowing in the detected body due to electromagnetic induction from the energized transmitting coil and thus changes. The signal processing unit calculates the position of the detected body based on the first voltage value and the second voltage value.

[0280] [Technical Solution 10]

[0281] The position detection device according to any one of Technical Solutions 1 to 8, wherein the configuration unit is a substrate; the signal output unit is provided on the substrate and includes a first receiving coil (32) and a second receiving coil (33) whose inductance changes corresponding to the position of the detection object; the first receiving coil outputs a change in its own inductance that changes corresponding to the position of the detection object as the first signal; the second receiving coil outputs a change in its own inductance that changes corresponding to the position of the detection object as the second signal; the signal processing unit calculates the position of the detection object based on the change in the inductance of the first receiving coil and the change in the inductance of the second receiving coil.

[0282] [Technical Solution 11]

[0283] The position detection device according to Technical Solution 9 or 10, wherein the first receiving coil and the second receiving coil include portions having a spiral pattern shape.

[0284] [Technical Solution 12]

[0285] The position detection device according to Technical Solution 9 or 10, for the first receiving coil and the second receiving coil, one of the first receiving coil and the second receiving coil includes a pattern shape depicting a sine curve, and the other of the first receiving coil and the second receiving coil includes a pattern shape depicting a cosine curve having a different phase from the sine curve.

[0286] [Technical Solution 13]

[0287] The position detection device according to any one of Technical Solutions 1 to 8, wherein magnets (110, 120, 130) are arranged on the detection object; the signal output unit has a first magnetic detection unit (61) that outputs the first signal based on a change in a magnetic field received from the magnet and changing corresponding to the position of the detection object, and a second magnetic detection unit (62) that outputs the second signal.

Claims

1. A position detection device for detecting the position of a detection object (20, 100). The position detection device includes: Signal output units (32, 33, 61, 62) that output a first signal (V1) in a sine wave form corresponding to the position of the detection object and a second signal (V2) corresponding to the position of the detection object, where the second signal is in a cosine wave form with a phase different from that of the first signal; A configuration unit (30, 10) provided with the signal output units and configured to face the detection object in a state separated from the detection object; and A signal processing unit (50) that calculates the position of the detection object, i.e., the detection object position, when the detection object is displaced within a specified detection range based on the first signal and the second signal. The signal processing unit corrects the first signal and the second signal, calculates the position of the detection object before correction, i.e., the pre-correction detection object position, based on the corrected first signal and second signal, operates on a correction function obtained from the error of the calculated pre-correction detection object position, and can correct the pre-correction detection object position calculated for each of the multiple intervals when the detection range is divided into multiple intervals. When the interval between the detection object and the configuration unit in the direction in which the detection object faces the configuration unit, i.e., the facing direction, is a gap (G), the reference gap is set as a reference, the near gap is set as the gap in which the interval between the detection object and the configuration unit is smaller than the reference gap, and the far gap is set as the gap in which the interval between the detection object and the configuration unit is larger than the reference gap. The first signal and the second signal are corrected so that the errors of the pre-correction detection object positions when the configuration unit is respectively configured at the reference gap, one or more of the near gaps, and one or more of the far gaps are respectively close to 0, and correction values in the correction function are derived for each of the multiple intervals.

2. A position detection device for detecting the position of a detection object (20, 100). The position detection device includes: Signal output units (32, 33, 61, 62) that output a first signal (V1) in a sine wave form corresponding to the position of the detection object and a second signal (V2) corresponding to the position of the detection object, where the second signal is in a cosine wave form with a phase different from that of the first signal; The configuration unit (30, 10) is provided with the signal output unit and is disposed opposite to the detection object in a state of being separated from the detection object; And A signal processing unit (50) that calculates the position of the detection object, i.e., the detection object position, when the detection object is displaced within a specified detection range based on the first signal and the second signal. The signal processing unit has: A signal correction unit (54) that corrects the first signal and the second signal; A position calculation unit (55) that calculates the position of the detection object before correction, i.e., the pre-correction detection object position, based on the first signal and the second signal corrected by the signal correction unit; And The interval correction unit (56) operates on a correction function obtained from an error in the pre-correction detected body position calculated by the position calculation unit, and corrects the pre-correction detected body position calculated by the position calculation unit for each of the plurality of intervals when dividing the detection range into a plurality of intervals. When the interval between the detected body and the arrangement unit in the facing direction, which is the direction in which the detected body faces the arrangement unit, is defined as the gap (G), the reference gap is defined as the reference gap, the near gap is defined as the gap in which the interval between the detected body and the arrangement unit is smaller than the reference gap, and the far gap is defined as the gap in which the interval between the detected body and the arrangement unit is larger than the reference gap. The signal correction unit corrects the first signal and the second signal such that the errors in the pre-correction detected body positions when the arrangement unit is respectively arranged at the reference gap, one or more of the near gaps, and one or more of the far gaps approach zero. The interval correction unit derives a correction value in the correction function for each of the plurality of intervals.

3. The position detection device according to claim 2, The detected body is a rotating body and can rotate within a specified rotation range smaller than from 0° to 360°. The signal output unit outputs the first signal and the second signal corresponding to the rotation angle of the detected body when the detected body rotates within the specified rotation range. The signal correction unit corrects the first signal and the second signal such that the error in the pre-correction detected body position within the specified rotation range calculated by the position calculation unit approaches zero. The position calculation unit calculates the pre-correction detected body position within the specified rotation range based on the first signal and the second signal corrected by the signal correction unit.

4. The position detection device according to claim 2 or 3, The reference gap is set to the size at the center between the size of the farthest near gap among one or more of the near gaps from the reference gap and the size of the farthest far gap among one or more of the far gaps from the reference gap.

5. The position detection device according to claim 2 or 3, The signal correction unit corrects at least one of the phase, gain, and offset of the first signal, and corrects at least one of the phase, gain, and offset of the second signal.

6. The position detection device according to claim 5, The signal correction unit corrects the offset of the first signal and corrects the offset of the second signal such that the difference between the error in the pre-correction detected body position when the arrangement unit is arranged at the reference gap and the error in the pre-correction detected body position when the arrangement unit is arranged at the far gap approaches zero.

7. The position detection device according to claim 5, The signal processing unit operates on the arctangent function based on the first signal and the second signal and performs an arctangent transformation to calculate the position of the detected body. The signal correction unit corrects the offset of the first signal and the offset of the second signal in such a manner that when the configuration unit is configured as the far gap, the first-order component obtained by the signal processing unit performing the arctangent transformation on the first signal and the second signal is close to the first-order component obtained by the signal processing unit performing the arctangent transformation on the first signal and the second signal when the configuration unit is configured as the near gap.

8. The position detection device according to claim 7, The offset of the first signal includes: a first fixed offset, which is an offset component that does not depend on the change in the amplitude of the first signal; and a first variable offset, which is an offset component whose magnitude changes corresponding to the change in the amplitude of the first signal. The offset of the second signal includes: a second fixed offset, which is an offset component that does not depend on the change in the amplitude of the second signal; and a second variable offset, which is an offset component whose magnitude changes corresponding to the change in the amplitude of the second signal. The signal correction unit adjusts the first fixed offset in such a manner that the relationship between the change amount of the amplitude of the first signal and the change amount of the offset of the first signal obtained based on the change amount of the amplitude of the first signal is a proportional relationship, and adjusts the second fixed offset in such a manner that the relationship between the change amount of the amplitude of the second signal and the change amount of the offset of the second signal obtained based on the change amount of the amplitude of the second signal is a proportional relationship. The interval correction unit corrects the pre-correction detected body position calculated by the position calculation unit for each of the plurality of intervals in such a manner as to remove the first-order component included in the position of the detected body calculated by performing the arctangent transformation on the first signal and the second signal.

9. The position detection device according to claim 2 or 3, The configuration unit is a substrate. The signal output unit is formed on the substrate and includes a transmitting coil (31), a first receiving coil (32), and a second receiving coil (33) that are inductively coupled by electromagnetic induction generated by energizing the transmitting coil. The first receiving coil outputs the first signal corresponding to the position of the detected body as a first voltage value, and the first signal changes due to the influence of the eddy current flowing in the detected body due to the electromagnetic induction from the energized transmitting coil. The second receiving coil outputs the second signal corresponding to the position of the detected body as a second voltage value, and the second signal changes due to the influence of the eddy current flowing in the detected body due to the electromagnetic induction from the energized transmitting coil. The signal processing unit calculates the position of the detected body based on the first voltage value and the second voltage value.

10. The position detection device according to claim 2 or 3, The configuration unit is a substrate. The signal output unit is provided on the substrate and includes a first receiving coil (32) and a second receiving coil (33) whose inductance changes corresponding to the position of the detected body. The first receiving coil outputs the change in its own inductance that changes corresponding to the position of the detection object as the first signal. The second receiving coil outputs the change in its own inductance that changes corresponding to the position of the detection object as the second signal. The signal processing unit calculates the position of the detection object based on the change in the inductance of the first receiving coil and the change in the inductance of the second receiving coil.

11. The position detection device according to claim 9, The first receiving coil and the second receiving coil include portions having a spiral pattern shape.

12. The position detection device according to claim 9, For the first receiving coil and the second receiving coil, one of the first receiving coil and the second receiving coil includes a pattern shape depicting a sine curve, and the other of the first receiving coil and the second receiving coil includes a pattern shape depicting a cosine curve with a phase different from that of the sine curve.

13. The position detection device according to claim 2 or 3, Magnets (110, 120, 130) are arranged on the detection object. The signal output unit has a first magnetic detection unit (61) and a second magnetic detection unit (62). The first magnetic detection unit (61) outputs the first signal based on the change in the magnetic field received from the magnet that changes corresponding to the position of the detection object, and the second magnetic detection unit (62) outputs the second signal based on the change in the magnetic field received from the magnet that changes corresponding to the position of the detection object.

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