Magnetic encoder based on double vertical magnetic resistance units

Abstract

The invention discloses a magnetic encoder based on double vertical magnetic resistance units, and relates to the technical field of magnetic sensors, and the magnetic encoder comprises a first induction magnetic head, a second induction magnetic head and a signal processing assembly. The first induction magnetic head, the second induction magnetic head and the signal processing assembly are integrated into a magnetic encoder chip; the two groups of induction magnetic heads are arranged in a manner of being perpendicular to a packaging substrate of the magnetic encoder chip through 90-degree side installation, the signal processing assembly is horizontally laid on the plane of the substrate, and the mode of 90-degree side installation of the induction magnetic heads is innovatively adopted to directly induce the magnetic field angle of the multi-antipode magnets on the inner and outer rings of the permanent magnet coded disc; and the induction magnetic head and the signal processing assembly are integrated into one encoder chip, so that the system size is remarkably reduced, and the magnetic encoder is particularly suitable for application scenes where high-precision magnetic encoders need to be installed on various small mechanisms.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic sensors, in particular to a magnetic encoder based on dual perpendicular magnetoresistive units. Background Art

[0002] A magnetic encoder is a sensor that measures angle, position, and speed based on changes in the sensed magnetic field. It is widely used in fields such as motor control, industrial automation, robotics, and automotive electronics. It is a critical sensor used in large quantities and can operate in harsh environments. Currently, magnetic encoders used in the market are primarily based on the Hall effect, magnetoresistive, and electromagnetic induction principles. Magnetic encoders based on the Hall effect principle measure the magnetic field strength and then calculate the magnetic field angle. However, they have the disadvantages of requiring high mounting clearances, being sensitive to shock and vibration, having low resolution, and being sensitive to stress. Magnetic encoders based on the electromagnetic induction principle, on the other hand, inject a high-frequency carrier into the transmitting coil, generating eddy currents through specially designed metal sheets that move with the rotor. The magnitude of the eddy currents is related to the rotor angle, and the eddy currents also change the mutual inductance between the transmitting and receiving coils. Ultimately, the receiving coil receives a signal containing the rotor angle information, and the angle information is obtained through back-end signal processing. However, magnetic encoders based on the electromagnetic induction principle have the disadvantages of being large in size, requiring high mounting clearances, and being sensitive to metal in the surrounding area.

[0003] With the miniaturization of motor size and the continuous development of robots, the demand for high-precision and high-resolution magnetic encoders is increasing. However, magnetic encoders based on the Hall effect principle are difficult to further increase resolution and accuracy without increasing system latency. Magnetic encoders based on the electromagnetic induction principle are difficult to miniaturize to ensure sufficient signal strength and are susceptible to interference from adjacent metal caused by increasingly compact installation structures. Therefore, magnetic encoders based on the Hall effect and electromagnetic induction principles cannot meet the increasingly high performance requirements. Summary of the Invention

[0004] The object of the present invention is to provide a magnetic encoder based on dual perpendicular magnetoresistive units to solve the problems raised in the prior art.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: a magnetic encoder based on a dual perpendicular magnetoresistive unit, the magnetic encoder comprising a first inductive head, a second inductive head and a signal processing component; the first inductive head, the second inductive head and the signal processing component are combined into a magnetic encoder chip.

[0006] Furthermore, the first inductive head and the second inductive head are placed at a 90-degree side-mounting perpendicular to the packaging substrate of the magnetic encoder chip. When the permanent magnetic code disk rotates, the magnetic field at the magnetic encoder basically changes in the XZ plane. Therefore, the inductive head needs to be installed at a 90-degree side-mounting perpendicularly on the packaging substrate through a special packaging process to directly sense the angle change of the magnetic field in the XZ plane; the signal processing component is placed flat on the substrate plane, and the two groups of inductive heads and the signal processing component are electrically connected through the routing and bonding of the packaging substrate, and are formed into a magnetic encoder chip through packaging; integrating the inductive head and the signal processing component into an encoder chip significantly reduces the system size, which is particularly suitable for application scenarios where various small organizations need to install high-precision magnetic encoders.

[0007] Furthermore, the magnetic encoder is used in conjunction with a permanent magnetic code disk; the permanent magnetic code disk consists of two circles of multi-pole magnets in an inner and outer rings, the difference in the number of magnetic pole pairs between the outer and inner ring multi-pole magnets is 1, the number of magnetic pole pairs of the outer ring multi-pole magnets is D, and the number of magnetic pole pairs of the inner ring multi-pole magnets is D-1, and both the inner and outer ring multi-pole magnets are magnetized with N / S poles alternately; and the magnetic encoder obtains the absolute angular position of each circle through the vernier principle, and improves the angular resolution and accuracy through the larger number of magnetic pole pairs of the inner and outer ring magnets.

[0008] Furthermore, the first inductive magnetic head and the second inductive magnetic head correspond to the inner and outer multi-pole magnets respectively, and are used to sense the magnetic field angles of the inner and outer multi-pole magnets respectively and output two sets of voltage signals to the signal processing component respectively.

[0009] Furthermore, there is a phase difference between the two sets of voltage signals output by the first inductive head and the second inductive head. If the permanent magnetic code disk rotates one circle, the phase difference between the two sets of voltage signals increases from 0 to 360 degrees.

[0010] Furthermore, the signal processing component processes the voltage signals output by the first inductive head and the second inductive head through an analog front end and then inputs them into an ADC to convert them into digital signals.

[0011] Furthermore, the voltage signals output by the first inductive head and the second inductive head are converted into digital signals, and then processed by the digital circuit algorithm of the signal processing component to obtain the magnetic angle signal α corresponding to the inner ring multi-pole magnet. i and the magnetic angle signal α corresponding to the outer ring multi-pole magnet o And the absolute angle signal α is obtained through the vernier principle algorithm.

[0012] Furthermore, the first inductive magnetic head and the second inductive magnetic head are manufactured based on a magnetoresistive unit.

[0013] Furthermore, the magnetoresistive units used to manufacture the induction head include three types: anisotropic magnetoresistive, giant magnetoresistive and tunnel magnetoresistive. One of the three types of magnetoresistive units is selected when manufacturing the induction head. The magnetic encoder based on the magnetoresistive induction principle directly measures the magnetic field angle change of the inner and outer ring multi-pole magnets, can adapt to a larger installation gap range, is insensitive to shock and vibration, and at the same time gives full play to the advantages of high sensitivity of the magnetoresistive unit and the system advantages of a permanent magnetic code disk with a large number of magnetic poles, thereby obtaining a high-precision and high-resolution magnetic encoder.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The magnetic encoder based on the magnetoresistive induction principle proposed in the present invention can adapt to a larger installation gap range and is insensitive to shock and vibration. At the same time, it fully utilizes the advantages of the high sensitivity of the magnetoresistive unit and the system advantages of the large number of magnetic pole pairs of the permanent magnetic code disk to obtain a high-precision and high-resolution magnetic encoder; and innovatively adopts a 90-degree side-mounted sensing head to directly sense the magnetic field angle of the multi-pole magnets on the inner and outer rings of the permanent magnetic code disk; and integrates the sensing head and signal processing components into an encoder chip, which significantly reduces the system size. It is particularly suitable for application scenarios where various small organizations need to install high-precision magnetic encoders. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a working diagram of the magnetic encoder and the permanent magnetic code disk in the present invention; Figure 2 This is a structural schematic diagram of a magnetic encoder based on dual perpendicular magnetoresistive units according to the present invention; Figure 3 This is a structural schematic diagram of a permanent magnetic code disk used in conjunction with a magnetic encoder based on dual perpendicular magnetoresistive units according to the present invention; Figure 4 It is the induced voltage signal output by two sets of inductive heads of a magnetic encoder based on dual perpendicular magnetoresistive units of the present invention; Figure 5 The two sets of angle signals obtained by preliminary processing of the induction signals output by the two sets of induction heads of the present invention by the signal processing components and the absolute angle signal obtained by further processing; In the figure: 10: magnetic encoder; 20: permanent magnetic code disk; 101: first inductive head; 102: second inductive head; 103: signal processing component; 201: inner ring multi-pole magnet; 202: outer ring multi-pole magnet. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] like Figure 1-Figure 5 As shown, the present invention provides a technical solution, a magnetic encoder based on a dual perpendicular magnetoresistive unit, the magnetic encoder 10 includes a first inductive head 101, a second inductive head 102 and a signal processing component 103; the first inductive head 101, the second inductive head 102 and the signal processing component 103 are combined into a magnetic encoder chip.

[0018] The first inductive head 101 and the second inductive head 102 are placed at a 90-degree side-mounted position perpendicular to the packaging substrate of the magnetic encoder chip. When the permanent magnetic code disk 20 rotates, the magnetic field at the magnetic encoder 10 basically changes in the XZ plane. Therefore, the inductive head needs to be installed at a 90-degree side-mounted position perpendicularly on the packaging substrate through a special packaging process to directly sense the angle change of the magnetic field in the XZ plane; the signal processing component 103 is placed flat on the plane of the substrate, and the first inductive head 101 and the second inductive head 102 and the signal processing component 103 are electrically connected through the routing and bonding of the packaging substrate, and are formed into a magnetic encoder chip through packaging; integrating the inductive head and the signal processing component into an encoder chip significantly reduces the system size, which is particularly suitable for application scenarios where various small organizations need to install high-precision magnetic encoders.

[0019] The magnetic encoder 10 is used in conjunction with a permanent magnetic code disk 20; the permanent magnetic code disk 20 consists of two inner and outer circles of multi-pole magnets. The difference in the number of magnetic pole pairs between the outer circle multi-pole magnet 202 and the inner circle multi-pole magnet 201 is 1, the number of magnetic pole pairs of the outer circle multi-pole magnet is D, and the number of magnetic pole pairs of the inner circle multi-pole magnet is D-1. Both the inner and outer circle multi-pole magnets are magnetized with alternating N / S poles. The magnetic encoder obtains the absolute angular position of each circle through the vernier principle, and improves the angular resolution and accuracy by using the larger number of magnetic pole pairs of the inner and outer circle magnets.

[0020] The first inductive head 101 and the second inductive head 102 correspond to the inner and outer multi-pole magnets respectively, and are used to sense the magnetic field angles of the inner and outer multi-pole magnets and output two sets of voltage signals to the signal processing component 103 respectively.

[0021] There is a phase difference between the two sets of voltage signals output by the first inductive head 101 and the second inductive head 102 . If the permanent magnetic code disk 20 rotates one circle, the phase difference between the two sets of voltage signals increases from 0 to 360 degrees.

[0022] The signal processing component 103 processes the voltage signals output by the first inductive head 101 and the second inductive head 102 through an analog front end and then inputs them into an ADC to convert them into digital signals.

[0023] The voltage signals output by the first inductive head 101 and the second inductive head 102 are converted into digital signals and then processed by the digital circuit algorithm of the signal processing component 103 to obtain the magnetic angle signal α corresponding to the inner ring multi-pole magnet 201. i and the magnetic angle signal α corresponding to the outer ring multi-pole magnet 202 o And the absolute angle signal α is obtained through the vernier principle algorithm.

[0024] The first inductive magnetic head 101 and the second inductive magnetic head 102 are manufactured based on magnetoresistive cells.

[0025] The magnetoresistive units used to manufacture induction heads include three types: anisotropic magnetoresistive, giant magnetoresistive, and tunnel magnetoresistive. One of the three types of magnetoresistive units is selected when manufacturing the induction head. The magnetic encoder based on the magnetoresistive induction principle directly measures the magnetic field angle changes of the inner and outer ring multi-pole magnets, can adapt to a larger installation gap range, and is insensitive to shock and vibration. At the same time, it fully utilizes the advantages of the high sensitivity of the magnetoresistive unit and the system advantages of the permanent magnetic code disk with a large number of magnetic pole pairs, resulting in a high-precision and high-resolution magnetic encoder.

[0026] Example 1: A magnetic encoder chip 10 is placed opposite to a permanent magnetic code disk 20; the permanent magnetic code disk 20 is mounted on a mechanism to be measured and rotates synchronously with the mechanism to be measured; when the permanent magnetic code disk 20 rotates, the magnetic encoder chip 10 senses the change in the magnetic field angle of the permanent magnetic code disk 20 and outputs an absolute angle signal of one rotation of the permanent magnetic code disk 20; the relative position relationship between the magnetic encoder chip 10 and the permanent magnetic code disk 20 is as follows Figure 1 shown.

[0027] A magnetic encoder chip 10, which integrates a first inductive head 101, a second inductive head 102 and a signal processing component 103, such as Figure 2 As shown; The first inductive magnetic head 101 and the second inductive magnetic head 102 are manufactured based on a magnetoresistive unit; the magnetoresistive unit is selected from one of anisotropic magnetoresistive (AMR), giant magnetoresistive (GMR) and tunnel magnetoresistive (TMR); The first inductive magnetic head 101 and the second inductive magnetic head 102 are placed at a 90-degree side-mounted position perpendicular to the package substrate of the magnetic encoder chip. The signal processing component 103 is placed flat on the plane of the package substrate. The two sets of inductive magnetic head signal processing components 103 are electrically connected through the routing and bonding of the package substrate, and are packaged to form a magnetic encoder chip. The magnetic encoder 10 is used in conjunction with a permanent magnetic code disk 20. The permanent magnetic code disk 20 is composed of two inner and outer rings of multi-pole magnets. The difference in the number of magnetic pole pairs between the outer ring multi-pole magnet 202 and the inner ring multi-pole magnet 201 is 1. The number of magnetic pole pairs of the outer ring multi-pole magnet is D, and the number of magnetic pole pairs of the inner ring multi-pole magnet is D-1. The structural diagram of the permanent magnetic code disk 20 is shown in FIG. Figure 3 As shown, the inner ring multi-pole magnet 201 and the outer ring multi-pole magnet 202 are both magnetized with N / S poles alternately.

[0028] When the permanent magnetic code disk 20 rotates, the magnetic field at the magnetic encoder 10 basically changes in the XZ plane. Therefore, it is necessary to install the first inductive head 101 and the second inductive head 102 vertically on the packaging substrate at 90 degrees through a special packaging process to directly sense the angle change of the magnetic field in the XZ plane.

[0029] The first inductive magnetic head 101 and the second inductive magnetic head 102 correspond to the inner ring multi-pole magnet 201 and the outer ring multi-pole magnet 202, respectively, and are used to sense the magnetic field angle changes of the inner ring multi-pole magnet 201 and the outer ring multi-pole magnet 202, respectively, thereby outputting two sets of voltage signals to the signal processing component 103. The output two sets of voltage signals are as follows: Figure 4 As shown, the two sets of voltage signals output by the first inductive head 101 are Vcos_i and Vsin_i, and the two sets of voltage signals output by the second inductive head 102 are Vcos_o and Vsin_o. There is a phase difference between the two sets of voltage signals output by the first inductive head 101 and the second inductive head 102. When the permanent magnetic code disk 20 rotates one circle, the phase difference increases from 0 to 360 degrees.

[0030] The signal processing component 103 processes the voltage signals output by the two sets of inductive heads through the analog front end and then enters the ADC to convert them into digital signals. The digital circuit processes them to obtain the magnetic field angle signals α corresponding to the inner ring multi-pole magnet 201. i and the magnetic field angle signal α of the outer ring multi-pole magnet 202 o ,like Figure 5 As shown, after further processing by the signal processing component 103, the magnetic field angle signal α i and α o The absolute angle is calculated using the vernier principle algorithm. The absolute angle calculation formula is as follows: α=int((α o -α i ) / (360 / D))*(360 / D)+α o / D; Then, the absolute angle signal α corresponding to one rotation of the permanent magnetic code disk 20 is output according to the calculation result.

[0031] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A magnetic encoder based on dual perpendicular magnetoresistive units, characterized in that: The magnetic encoder (10) comprises a first inductive magnetic head (101), a second inductive magnetic head (102), and a signal processing component (103); the first inductive magnetic head (101), the second inductive magnetic head (102), and the signal processing component (103) are assembled into a magnetic encoder chip; The first inductive magnetic head (101) and the second inductive magnetic head (102) are placed perpendicular to the packaging substrate of the magnetic encoder chip by side mounting at 90 degrees. When the permanent magnetic code disk rotates, the magnetic field at the magnetic encoder changes in the XZ plane. The inductive magnetic heads are installed perpendicularly on the packaging substrate at 90 degrees through a special packaging process, and can directly sense the angle change of the magnetic field in the XZ plane. The signal processing component (103) is placed horizontally on the substrate plane. The two sets of inductive magnetic heads and the signal processing component (103) are electrically connected through the routing and bonding of the packaging substrate, and are packaged to form a magnetic encoder chip. The magnetic encoder (10) is used in conjunction with a permanent magnetic code disk (20); the permanent magnetic code disk (20) is composed of two inner and outer circles of multi-pole magnets, the number of magnetic pole pairs of the outer circle multi-pole magnets (202) and the inner circle multi-pole magnets (201) differing by 1; and the magnetic encoder (10) obtains the absolute angular position of each circle through the vernier principle.

2. The magnetic encoder based on dual perpendicular magnetoresistive units according to claim 1, characterized in that: The first inductive magnetic head (101) and the second inductive magnetic head (102) correspond to the inner ring and outer ring multi-pole magnets, respectively, and are used to sense the magnetic field angles of the inner ring and outer ring multi-pole magnets, respectively, and output two sets of voltage signals to the signal processing component (103).

3. The magnetic encoder based on dual perpendicular magnetoresistive units according to claim 1, characterized in that: There is a phase difference between the two sets of voltage signals output by the first inductive magnetic head (101) and the second inductive magnetic head (102). If the permanent magnetic code disk (20) rotates one circle, the phase difference between the two sets of voltage signals increases from 0 to 360 degrees.

4. The magnetic encoder based on dual perpendicular magnetoresistive units according to claim 1, characterized in that: The signal processing component (103) processes the voltage signals output by the first inductive magnetic head (101) and the second inductive magnetic head (102) through an analog front end and then inputs them into an ADC for conversion into digital signals.

5. The magnetic encoder based on dual perpendicular magnetoresistive units according to claim 1, characterized in that: The voltage signals output by the first inductive magnetic head (101) and the second inductive magnetic head (102) are converted into digital signals, and then processed by the digital circuit algorithm of the signal processing component (103) to obtain a magnetic angle signal α corresponding to the inner ring multi-pole magnet (201). i and the magnetic angle signal α corresponding to the outer ring multi-pole magnet (202) o And the absolute angle signal α is obtained through the vernier principle algorithm.

6. The magnetic encoder based on dual perpendicular magnetoresistive units according to claim 1, characterized in that: The first inductive magnetic head (101) and the second inductive magnetic head (102) are manufactured based on a magnetoresistive unit.

7. The magnetic encoder based on dual perpendicular magnetoresistive units according to claim 6, characterized in that: The magnetoresistive units used to manufacture the inductive magnetic head include three types: anisotropic magnetoresistive, giant magnetoresistive, and tunnel magnetoresistive. One of the three types of magnetoresistive units is selected when manufacturing the inductive magnetic head.

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