Angle detection device

Abstract

An angle detecting device (4) includes an encoder section (6) having a magnetic track in which N poles and S poles are alternately arranged, and a magnetic sensor section (7) which opposes the magnetic track through a gap. In the magnetic track, a main magnetic track (2) having a magnetic pole width of (P) and a sub magnetic track (3) having a magnetic pole width of (Pn / (n-1)) are arranged adjacent to and parallel to each other along a length direction of a sheet-like magnetic material for encoder (1), when a reference magnetic pole width (P) and a reference number of magnetic poles (n) are set. In the encoder section (6), the sheet-like magnetic material for encoder (1) is fixed by being wound on an outer circumferential section or an inner circumferential section of a rotating body (5) with a length not exceeding a reference length (L=2Pn). A correction calculation section (10) is provided which corrects an absolute angle of the rotating body by multiplying the absolute angle calculated from an operation section (9) of the magnetic sensor section (7) by a correction coefficient corresponding to a diameter of the encoder section (6).

Description

[0001] Related applications

[0002] This application claims priority to JP Patent Application 2021-099722, filed on June 15, 2021, which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention relates to an angle detection device for detecting the rotation angle of a rotating axis or the like, and particularly to an angle detection device for detecting angles in a range of up to 360° with high resolution in order to position the joints of a robot or the like at a target position. Background Technology

[0004] In the past, various magnetic encoder devices for detecting rotation angles have been proposed.

[0005] In the magnetic encoder device disclosed in Patent Document 1, a cylindrical base is formed of sintered metal, and precision pressing is performed by pressing the outer circumferential surface, inner circumferential surface, and both end faces of the base. Then, the base is inserted into a mold, and a resin material mainly composed of thermoplastic resin and magnetic powder is injection molded into the mold cavity. Subsequently, two rows of magnetic encoder tracks are formed by multi-pole magnetization. These magnetic encoder tracks have multiple magnetic poles arranged circumferentially in the forming part, and the number of pole pairs is different for each pair.

[0006] The magnetic encoder, thus constructed, is fixed to the rotating body, with a magnetic sensor positioned adjacent to and opposite the encoder tracks. The magnetic sensor has two detection elements facing the two rows of encoder tracks respectively, and a processing unit. Based on the phase difference between the magnetic signals detected by the two detection elements, the absolute angle of the rotating body is calculated at high resolution and output as the sensor output.

[0007] The magnetic encoder disclosed in Patent Document 2 comprises a magnetic recording rotor and a magnetic information detection mechanism. In the magnetic recording rotor, a strip-shaped magnetic scale component with alternating N and S poles magnetized at equal intervals is attached to its outer peripheral surface. The magnetic information detection mechanism is positioned close to the magnetic recording rotor. This magnetic information detection mechanism includes two magnetic information detection elements spaced apart along the rotation direction of the magnetic recording rotor. Magnetic information formed on the magnetic scale component is detected by the two magnetic information detection elements, and the detection output generates A-phase, B-phase, and Z-phase signals. As a result, a high-precision, highly reliable, and versatile magnetic encoder can be achieved at a relatively low cost.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: JP 2015-75466

[0011] Patent Document 2: JP 2012-141259 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] In the technology disclosed in Patent Document 1, after a plastic magnet is integrally formed on a stamped sintered core iron, it is magnetized to form a number of magnetization poles determined by each rotation.

[0014] In order to achieve a high-resolution angle detection device using multi-row magnetic encoders while meeting constraints such as available space and cost, the magnetic sensors need to use mass-produced products that integrate the necessary functions into a single package.

[0015] Therefore, the main specifications such as pole width and number of pole pairs are predetermined and cannot be matched to individual specifications. For example, once the specifications such as pole width and number of pole pairs are determined, the diameter of the encoder part is determined by these specifications, and it cannot be manufactured with arbitrary diameters, thus limiting the degree of design freedom. In addition, since molded products are magnetized individually one by one, it is difficult to improve productivity. Furthermore, there is a problem that it is difficult to integrally form a molded product with the rotating body; the magnetized parts need to be installed as separate parts, which increases the size of the rotating body and thus its mass.

[0016] Furthermore, in order to manufacture magnetic encoder devices, it is necessary to manufacture molds for the core iron and molds for injection molding plastic magnets, which leads to high manufacturing costs.

[0017] The strip magnetic scale used in the technology disclosed in Patent Document 2 is lightweight and does not require molding molds, thus solving the aforementioned problems. However, there is no mention of improved resolution. Furthermore, although the two ends of the magnetic scale component attached to a portion of the circumference can be detected using the Z-phase signal, neither the A-phase nor the B-phase signal is output when the state of the ends of the magnetic scale component is detected. Therefore, for example, when using the angle detection signal for the control of rotating equipment, there is a problem that conventional control methods cannot be used.

[0018] The purpose of this invention is to solve the above-mentioned problems. The purpose of this invention is to provide a high-resolution angle detection device based on the principle of a multi-row magnetic encoder, which has a high degree of design freedom, can be miniaturized and lightweight, and can reduce manufacturing costs.

[0019] Technical solutions to the problem

[0020] In the following description, for ease of understanding and convenience, reference will be made to the reference numerals in the accompanying drawings of the embodiments to illustrate the present invention.

[0021] The angle detection devices 4, 4A, and 4B of the present invention include: encoder sections 6, 6A, and 6B having magnetic tracks with alternating N and S poles; and magnetic sensor sections 7 facing the magnetic tracks with a gap δ.

[0022] In the above magnetic track, when the reference magnetic pole width P and the reference number of magnetic pole pairs n are set, the main magnetic track 2 with a magnetic pole width of P and the auxiliary magnetic track 3 with a magnetic pole width of Pn / (n-1) are arranged adjacent to each other and parallel to each other along the length direction of the sheet encoder magnetic material 1. In the above encoder parts 6, 6A, and 6B, the above sheet encoder magnetic material 1 is wound around the outer or inner periphery of the rotating body 5, 5A, and 5B with a length not exceeding the reference length L = 2Pn and fixed thereon.

[0023] The aforementioned magnetic sensor unit 7 includes: two magnetic detection elements 8, which output magnetic signals to the main magnetic track 2 and the auxiliary magnetic track 3 respectively; and a calculation unit 9, which calculates the absolute angles of the rotating bodies 5, 5A, and 5B based on the magnetic signals from the magnetic detection elements 8.

[0024] The aforementioned angle detection device includes a correction calculation unit 10, which multiplies the calculated absolute angle by a correction coefficient corresponding to the diameter of the encoder units 6, 6A, and 6B to correct the absolute angle of the rotating bodies 5, 5A, and 5B.

[0025] According to this structure, a sheet-shaped encoder is fixed by winding a magnetic material 1 around the outer or inner periphery of the rotating bodies 5, 5A, and 5B, serving as the encoder sections 6, 6A, and 6B of the angle detection devices 4, 4A, and 4B. Therefore, even if the diameter of the encoder section is changed, no mold is needed, and encoder sections 6, 6A, and 6B of any diameter can be easily manufactured. The calculation unit 9 can calculate the absolute angle of the rotating bodies 5, 5A, and 5B with high resolution based on the magnetic signals of the two magnetic detection elements 8. The correction calculation unit 10 multiplies the calculated absolute angle by a correction coefficient corresponding to the diameter of the encoder sections 6, 6A, and 6B, so that even if the diameter of the encoder section is not L / π, the absolute angle of the rotating bodies 5, 5A, and 5B with a circumferential length L can still be detected with high resolution and accuracy. Furthermore, if existing rotating components 11A, 11B, and 11C are used as the aforementioned rotating bodies, there is no need to add encoders as other components, simplifying the structure of the angle detection device and enabling miniaturization and weight reduction.

[0026] When the encoder with a reference length of L is cut to any length using magnetic material 1 and the diameter of the encoder section 6, 6A, 6B wound around the outer or inner circumference of the rotating bodies 5, 5A, 5B is S, the correction calculation unit 10 can use the value L / (πS) obtained by dividing the reference length L by the product of the diameter S and π as the correction coefficient.

[0027] If the diameters of encoder sections 6, 6A, and 6B are not equal to the diameter S of L / π, the sensor output from the magnetic sensor section 7 will differ from the actual angle. However, if L / πS is multiplied by the sensor output as a correction coefficient, the correct angle will be obtained.

[0028] The included encoder sections 6, 6A, and 6B can be formed by winding the encoder magnetic material 1, whose length L1 of the main magnetic track 2 and the auxiliary magnetic track 3 is less than or equal to the reference length L, onto the outer or inner periphery of the rotating body 5, 5A, and 5B, whose circumference is longer than the length L1.

[0029] The angle detection device may further include: a limit angle storage unit 12, which is located at both ends of the magnetic track and stores the limit angle corresponding to the output of the magnetic sensor unit 7; and a detection range determination unit 13, which determines whether the absolute angle output from the magnetic sensor unit 7 is within the limit angle range and outputs an identification signal indicating whether it has deviated from the limit angle.

[0030] According to this configuration, if the rotation stops when an identification signal indicating a deviation from the limit angle is output, a normal sensor signal indicating the absolute angle is output, thereby allowing operation through normal control methods to avoid undetectable areas.

[0031] Rotating bodies 5, 5A, and 5B can be rotating components 11A, 11B, and 11C of a robot joint. When detecting the absolute angle of a robot joint, the required angle detection range is often less than 360°. In this case, if the encoder is positioned at a location where angle detection is not required using the seam of the magnetic material 1, the influence of the seam can be avoided, thus realizing an angle detection device. Furthermore, if existing rotating components 11A, 11B, and 11C of a robot joint are used as rotating bodies, and the encoder is directly wound around the rotating components 11A, 11B, and 11C using the magnetic material 1 for fixation, there is no need to install a separate encoder, enabling miniaturization and weight reduction of the robot joint.

[0032] Any combination of at least two structures disclosed in the claims and / or description and / or drawings is also included in this invention. In particular, any combination of two or more of the claims in the claims is also included in this invention. Attached Figure Description

[0033] The present invention can be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are for illustration and description only and should not be used to limit the scope of the invention. The scope of the invention is defined by the claims. In the drawings, the same reference numerals in multiple figures denote the same or equivalent parts.

[0034] Figure 1 The figure shows an example of the structure of the angle detection device according to the first embodiment of the present invention.

[0035] Figure 2 A perspective view showing the structure of the magnetic material used in the encoder of the aforementioned angle detection device;

[0036] Figure 3 This is a side view of the angle detection device described above;

[0037] Figure 4A This is a block diagram of the control system for the aforementioned angle detection device;

[0038] Figure 4B for Figure 4A A block diagram of partial changes to the control system;

[0039] Figure 5 A diagram showing the phase of the detection signal from the magnetic sensor section of the aforementioned angle detection device and the phase difference between the two detection signals;

[0040] Figure 6 A diagram illustrating an example structure of an angle detection device when the diameter of the encoder section differs from L / π;

[0041] Figure 7 This is a block diagram of the correction calculation unit of the angle detection device;

[0042] Figure 8 This diagram illustrates an example of the structure of an angle detection device with a gap formed between the seams of the encoder section;

[0043] Figure 9 This is a block diagram of the control system for the angle detection device;

[0044] Figure 10 This diagram illustrates an example of applying an arbitrary angle detection device to a robot joint. Detailed Implementation

[0045] [First Implementation]

[0046] Reference Figures 1-5 The angle detection device of the present invention will be described in the following description.

[0047] like Figure 1 and Figure 3As shown, the angle detection device 4 includes an encoder section 6 with a magnetic track and a magnetic sensor section 7 positioned opposite the magnetic track with a gap δ. The encoder section 6 is as follows... Figure 2 As shown, a magnetic track has alternating N and S poles. Within the magnetic track, with a reference pole width P and a reference pole pair number n, the main magnetic track 2 with a pole width (circumferential width) of P and the auxiliary magnetic track 3 with a pole width of Pn / (n-1) are arranged adjacent and parallel to each other along the length of the sheet encoder's magnetic material 1. Figure 1 As shown, the encoder section 6 is fixed by winding the aforementioned sheet-shaped encoder with magnetic material 1 around the cylindrical outer periphery 5a of the rotating body 5 with a length not exceeding the reference length L.

[0048] Figure 2 The encoder shown uses magnetic material 1, for example, by vulcanizing a rubber material mixed with magnetic powder into a sheet, cutting it to the necessary length, and then alternately magnetizing the N and S poles along the length direction with a predetermined pole width determined by the reference pole width P and the reference pole pair number n, forming a magnetic track with a main magnetic track 2 and a secondary magnetic track 3. Alternatively, the sheet magnetized to a length suitable for production equipment or material availability can be cut to the required length depending on the application. Furthermore, let L = 2Pn be the reference length.

[0049] For example, when the reference magnetic pole width P is 2mm and the number of reference magnetic pole pairs n is 32, the magnetization width (magnetization pitch) p2 (=P) of the main magnetic track 2 is 2mm, and the magnetization width p3 (=Pn / (n-1)) of the secondary magnetic track 3 is 2.0645mm. In the case of detecting a 360° absolute angle with the standard accuracy of a magnetic sensor, the number of magnetic pole pairs n2 (=n) of the main track 2 is 32 (64 poles in total, including N and S poles), and the number of magnetized magnetic pole pairs n3 (=n-1) of the secondary magnetic track 3 is 31 (62 poles in total, including N and S poles). The track length at this time is the reference length L, where L=2Pn=128mm.

[0050] Here, the main magnetic track 2 of the encoder magnetic material 1 is set to have a magnetization width of 2mm and 32 magnetic pole pairs, and the auxiliary magnetic track 3 is set to have a magnetization width of 2.0645mm and 31 magnetic pole pairs. However, the specifications of the magnetic poles of the encoder magnetic material can be appropriately selected according to the magnetic sensor unit used.

[0051] Figure 1The angle detection device 4 shown includes an encoder section 6 and a magnetic sensor section 7. The encoder section 6 is obtained by fixing the encoder with magnetic material 1 to the outer periphery 5a of the rotating body 5 using adhesive or double-sided tape. A hole 5b is formed in the center of the rotating body 5, and a rotating shaft (not shown) is inserted into the hole 5b in a manner that does not rotate relative to the rotating body 5. Alternatively, the rotating shaft can be integrally formed with the rotating body 5. The term "integrated" means that the rotating shaft and the rotating body 5 are formed from a single material as part or integral to a single object through forging, machining, or other methods, rather than being achieved by combining multiple components.

[0052] As shown in Figure 4(A), the magnetic sensor unit 7 includes: two magnetic detection elements 8, which output magnetic signals from the radial outer surface of the rotating body 5 to the main magnetic track 2 and the auxiliary magnetic track 3 respectively; and an arithmetic unit 9, which calculates the absolute angle of the rotating body 5 in high resolution based on the phase difference of the magnetic signals detected by the magnetic detection elements 8, and outputs it as a sensor output.

[0053] like Figure 2 As shown, a magnetic material 1 is used in the encoder with a track of reference length L spanning the entire length. Figure 1 As shown in Figure 4(A), when an encoder section 6 with a diameter of L / π is fabricated around the outer periphery 5a of the rotating body 5, the following applies. Figure 5 As shown, the arithmetic unit 9 utilizes the signal obtained from the main track 2 ( Figure 5 (A) and the signal obtained from sub-track 3 Figure 5 The phase difference between (B) Figure 5 The fact that (C) becomes a pole pair in one rotation allows for the detection of absolute angles with standard precision.

[0054] Also, settings Figure 2 The encoder with a track of reference length L shown is made of magnetic material 1, which is cut such that the track length is less than the reference track length L, and wound around it. Figure 1 On the rotating body 5 shown, even if there is a gap (circumferential gap) at the joint T between one end and the other end of the encoder section 6 in the length direction, if the diameter of the encoder section 6 is L / π, the absolute angle can be detected with the standard accuracy of the magnetic sensor within the range where the encoder magnet 1 is fixed.

[0055] Figure 5 (A) is the waveform of the detection signal corresponding to main track 2. Figure 5 (B) is the waveform of the detection signal corresponding to the sub-track 3. Figure 5 (C) represents the arithmetic unit 9 ( Figure 4A )according to Figure 5The waveform of the output signal obtained from the phase difference of the detection signals (A) and (B). Arithmetic unit ( Figure 4A The process involves converting the phase difference into an absolute angle based on predetermined calculation parameters. These calculation parameters are stored in a storage mechanism Mr, such as a non-volatile memory, included in the magnetic sensor unit 7 shown in Figure 4(A). In addition to storing the calculation parameters, the storage mechanism Mr also stores, in a rewritable manner, essential information for the device, such as the reference magnetic pole width P of the magnetic track, the number of reference magnetic pole pairs n, the number of magnetized pole pairs in each track 2 and 3, and the signal output method.

[0056] The angle detection device 4 has a correction calculation unit 10 after the arithmetic unit. The correction calculation unit 10 multiplies the absolute angle output from the arithmetic unit 9 by a correction coefficient corresponding to the diameter of the encoder unit 6 in order to correct the absolute angle of the rotating body 5.

[0057] When an encoder with a reference length L is cut to an arbitrary length using magnetic material 1 and wound around the outer periphery 5a of the rotating body 5, Figure 1 When the diameter of the encoder section 6 on the encoder is S, the correction calculation section 10 uses the value L / (πS) obtained by dividing the reference length L by the product of the diameter S and the pi as the correction coefficient.

[0058] If the diameter of encoder section 6 is not equal to L / π, the sensor output from the magnetic sensor will differ from the actual angle. However, the correct angle can be obtained by multiplying the sensor output by a correction factor. Assuming the diameter of encoder section 6 is S, as described above, the absolute angle output from the arithmetic unit can be multiplied by the correction factor L / (πS). The correction calculation unit 10 includes a storage function for storing correction factors and an arithmetic function, and performs correction calculations using the stored correction factors according to the arithmetic function. In this example, the correction calculation unit 10 is provided at the stage after the arithmetic unit 9 in the magnetic sensor section 7, but the correction calculation unit 10 can also be provided at the arithmetic unit itself. Furthermore, as... Figure 4B As shown, a calibration calculation unit 10 can also be provided as a dedicated circuit near the magnetic sensor unit 7. The calibration calculation unit may also include a host control unit (not shown).

[0059] <Functions and Effects>

[0060] According to the angle detection device 4 described above, Figure 1The sheet-like magnetic material 1 for encoding is wound and fixed around the outer periphery 5a of the rotating body 5, serving as the encoder section 6 of the angle detection device 4. Therefore, even if the diameter of the encoder section 6 changes, no mold is needed, and encoder sections 6 of any diameter can be easily manufactured. The calculation unit 9 calculates the absolute angle of the rotating body 5 at high resolution based on the magnetic signals from the two magnetic detection elements 8. The correction calculation unit 10 multiplies the calculated absolute angle by a correction coefficient corresponding to the diameter of the encoder section 6, thus ensuring accurate detection of the absolute angle of the rotating body 5 at high resolution even if the diameter of the encoder section 6 is not L / π. Furthermore, if an existing rotating component is used as the rotating body 5, there is no need to add an encoder as a separate component, simplifying the structure of the angle detection device 4 and enabling miniaturization and weight reduction.

[0061] <Regarding other implementation methods>

[0062] Next, another embodiment will be described. In the following description, the parts corresponding to the matters previously described in each embodiment are given the same reference numerals, and repeated descriptions are omitted. When only a part of the configuration is described, the other parts of the configuration are the same as the configuration described above, unless otherwise stated. The same configuration has the same effect. Not only can the parts specifically described in each embodiment be combined, but embodiments can also be partially combined, especially where there is no problem in combining them.

[0063] [Second Implementation]

[0064] Figure 6 This diagram illustrates a structural example of the angle detection device 4A when the diameter of the encoder section is different from L / π. Figure 7 This is a block diagram of the correction calculation unit 10 of the aforementioned angle detection device.

[0065] If the diameter of the encoder section, which is wound with magnetic material on the rotating body, is different from L / π, the sensor output from the magnetic sensor section will differ from the actual angle. In this case, if the angle detection device 4A is equipped with a correction calculation unit 10 and the sensor output is multiplied by a correction coefficient, the correct absolute angle can be obtained.

[0066] Figure 6 The following describes an angle detection device 4A as an encoder section 6A, wherein an encoder of length L is provided with a magnetic track of reference length L across its entire length using magnetic material 1. The encoder is cut into lengths of L / 2 using magnetic material 1 and wound once around the outer periphery 5a of the rotating body 5A in the circumferential direction to form an encoder section 6A with a diameter of L / (2π) that can detect an absolute angle of 360°.

[0067] Since the outer perimeter length of the encoder section 6A is half of the reference length L, the detection output of the absolute angle from the magnetic sensor section 7 is half of the actual angle. Therefore, by setting... Figure 7 The calibration calculation unit 10 shown multiplies the sensor output by a calibration coefficient "2" to obtain the actual absolute angle.

[0068] [Third Implementation]

[0069] Figure 8 The encoder uses magnetic material 1 wound around a portion of the outer periphery 5Ba of the rotating body 5B. An angle detection device 4B has a large gap between one end and the other end of the encoder section 6B along its length. Even when the diameter S of the encoder section 6B is not L / π (S≠L / π), it still works by the method described above. Figure 7 The calibration calculation unit 10 performs calibration calculations on the sensor output, enabling it to detect the actual absolute angle.

[0070] For example, when detecting absolute angles such as those of robot joints, the required angle detection range is often less than one full circle (360°), and the magnetic material used in the encoder may have seams or gaps. In this case, if the seams or gaps in the encoder's magnetic material are located in areas where angle detection is not required, the absolute angle can be detected while avoiding the influence of the seams or gaps.

[0071] Figure 10 The robot joint shown requires a small and lightweight structure. If the encoder is made of magnetic material 1 ( Figure 2 Cut to the required length, and then, using the known annular components of the robot joint as rotating bodies, the encoder is directly wound around the outer periphery of each rotating component 11A, 11B, 11C with magnetic material 1 to form an angle detection device 4B. In this way, it is not necessary to install the encoder as a separate component, and the miniaturization and weight reduction of the robot joint can be achieved.

[0072] like Figure 8 As in the example, if the magnetic track is shorter than the outer periphery 5Ba of the rotating body 5B, and if the magnetic track is not present at the position opposite to the magnetic sensor section 7, it is necessary to detect both ends of the magnetic track to avoid the inability to detect the current position of the rotating body 5B. In this embodiment, the angle detection device 4B can detect the absolute angle simply by turning on the power; therefore, as... Figure 9 As shown, at both ends of the magnetic track, there is a limit angle storage unit 12 that stores the angle (limit angle) output from the magnetic sensor unit. Furthermore, a detection range determination unit 13 is provided, which compares the contents of the limit angle storage unit 12 with the sensor output, determines whether the magnetic sensor unit is within the limit angle range, and outputs an identification signal.

[0073] Right now, Figure 8 The angle detection device 4B has an encoder section 6B, which fixes an encoder with a main magnetic track and an auxiliary magnetic track length L1 not exceeding the aforementioned reference length L by winding a magnetic material 1 around the outer periphery 5Ba of a rotating body 5B whose circumference is longer than the length L1. In this case, the angle detection device 4B includes: a limit angle storage section 12 located at both ends of the magnetic track and storing limit angles corresponding to the output of the magnetic sensor section 7; and a detection range determination section 13 that determines whether the absolute angle output from the magnetic sensor section 7 is within the limit angle range and outputs an identification signal indicating whether it has deviated from the limit angle range.

[0074] According to this scheme, if rotation stops when a recognition signal indicating that the angle has deviated from the limit angle is output, since the output is a normal sensor signal indicating the absolute angle, operation can be performed using normal control methods to avoid undetectable areas. Furthermore, in the limit angle storage unit 12, if the limit angle is set by observing the margin of one to several magnetic pole pairs from both ends of the track, the reliability of operation can be increased.

[0075] A plate encoder can be fixed by being wound around the inner circumference of a cylindrical rotating body using magnetic material.

[0076] Besides robot joints, angle detection devices can also be used in applications such as wheel bearings, steering mechanisms, precision positioning devices, machine tools, and industrial machinery.

[0077] As described above, preferred embodiments have been illustrated with reference to the accompanying drawings; however, various additions, modifications, and deletions can be made without departing from the scope of the invention. Therefore, such embodiments are also included within the scope of the invention.

[0078] Explanation of the labels:

[0079] The label 1 indicates that the encoder uses magnetic material;

[0080] Label 2 indicates the main track;

[0081] The number 3 indicates the secondary track;

[0082] The numbers 4, 4A, and 4B indicate angle detection devices;

[0083] The numbers 5, 5A, and 5B indicate solids of revolution;

[0084] The numbers 6, 6A, and 6B indicate the encoder section;

[0085] The number 7 indicates the magnetic sensor unit;

[0086] The number 8 indicates a magnetic detection element;

[0087] Label 9 indicates the arithmetic unit;

[0088] The number 10 indicates the calibration calculation unit;

[0089] The designations 11A, 11B, and 11C indicate rotating components;

[0090] The number 12 indicates the extreme angle storage section;

[0091] The number 13 indicates the detection range judgment section.

Claims

1. An angle detection device, the angle detection device comprising: The encoder section has magnetic tracks with alternating N and S poles; And a magnetic sensor unit, which is positioned opposite the aforementioned magnetic track across a gap. In the aforementioned magnetic track, when the reference magnetic pole width P and the reference number of magnetic pole pairs n are set, the main magnetic track with a magnetic pole width of P and the auxiliary magnetic track with a magnetic pole width of Pn / (n-1) are arranged adjacent to each other and parallel to each other along the length direction of the magnetic material of the sheet encoder. In the aforementioned encoder section, the aforementioned magnetic material of the sheet encoder is wound around the outer or inner periphery of the rotating body and fixed with a length not exceeding the reference length L = 2Pn. The aforementioned magnetic sensor unit includes two magnetic detection elements, which respectively output magnetic signals to the main magnetic track and the auxiliary magnetic track. And a calculation unit, which calculates the absolute angle of the rotating body based on the magnetic signals of these magnetic detection elements; The aforementioned angle detection device includes a correction calculation unit that multiplies the calculated absolute angle by a correction coefficient corresponding to the diameter of the encoder unit to correct the absolute angle of the rotating body.

2. The angle detection device according to claim 1, characterized in that, When the encoder of the aforementioned reference length L is cut to any length using magnetic material, and the diameter of the encoder portion wound around the outer or inner periphery of the rotating body is S, the correction calculation unit uses the value L / (πS) obtained by dividing the reference length L by the product of the diameter S and π as the correction coefficient.

3. The angle detection device according to claim 1 or 2, characterized in that, The encoder portion included is formed by winding the encoder, whose main magnetic track and the auxiliary magnetic track length L1 is less than or equal to the reference length L, with magnetic material and fixing it to the outer or inner periphery of the rotating body whose circumference is longer than the length L1. The angle detection device further includes: a limit angle storage unit located at both ends of the magnetic track and storing limit angles corresponding to the output of the magnetic sensor unit; and a detection range determination unit that determines whether the absolute angle output from the magnetic sensor unit is within the range of the limit angle and outputs an identification signal indicating whether it has deviated from the limit angle.

4. The angle detection device according to claim 1 or 2, characterized in that, The aforementioned rotating body is the rotating component of a robot joint.

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