High-precision absolute value magnetic encoder and signal processing method thereof

Abstract

The application discloses a high-precision absolute value magnetic encoder and a signal processing method thereof. The absolute value magnetic encoder comprises a cursor magnetic code disc, an incremental magnetic code disc, a Hall magnetic encoder chip, an AMR sensor chip, a subdivision chip and a single-chip microcomputer. The Hall magnetic encoder chip is used for sensing the magnetic signal of the cursor magnetic code disc and outputting an absolute angle position signal. The AMR sensor chip is used for sensing the magnetic signal of the incremental magnetic code disc and outputting a cosine voltage signal. The subdivision chip is used for receiving the cosine voltage signal and outputting an angle increment signal when the absolute value magnetic encoder rotates. The single-chip microcomputer is used for fusing the absolute angle position signal and the angle increment signal and outputting a high-precision angle position signal. The application fuses two kinds of magnetic signal measurement means with different principles on one encoder, can provide absolute position when the encoder is powered on, and improves the measurement precision and resolution of the absolute value encoder.

Description

Technical Field

[0001] This invention relates to the field of encoder technology, and in particular to a high-precision absolute magnetic encoder and its signal processing method. Background Technology

[0002] An encoder is a sensor that converts mechanical displacement on an output shaft into pulse signals or digital quantities through signal conversion. Based on their operating characteristics, encoders can be divided into incremental encoders and absolute encoders. Incremental encoders have advantages such as simple construction, long mechanical life, strong anti-interference ability, suitability for speed and length transmission, and high reliability. Their disadvantage is that they cannot directly output position signals. Absolute encoders feature high bit resolution, and each position determined by their mechanical position is unique, eliminating the need for reference points. They offer higher anti-interference and reliability, and have excellent positioning capabilities.

[0003] Absolute encoders can be further divided into optical and mechanical types. While optical absolute encoders are accurate, they have lower environmental resistance; their accuracy will decrease significantly in harsh environments, and they may even become ineffective. Among mechanical absolute encoders, magnetic encoders use magnetic elements as sensors. Based on the Hall effect or magnetoresistive effect, they can achieve high-precision measurement of angular displacement. They are easy to miniaturize, achieve high precision and high resolution, and have characteristics such as vibration resistance, shock resistance, and long lifespan. They are widely used in motor servo systems and automatic control systems.

[0004] Currently, absolute magnetic encoders typically use an absolute vernier code disk. However, the data reading accuracy of the absolute vernier code disk is lower than that of the incremental code disk, resulting in lower angular accuracy of the encoder output. While using an incremental code disk instead of the absolute vernier code disk can provide high-precision relative position, the incremental code disk has low resolution and cannot provide absolute position when the encoder is powered on. Summary of the Invention

[0005] The purpose of this invention is to provide a high-precision absolute magnetic encoder and its signal processing method. By using two magnetic code disks, two different magnetic signal measurement methods are integrated into one encoder, which can provide absolute position when the encoder is powered on and improve the measurement accuracy and resolution of the absolute encoder.

[0006] To achieve the above objectives, the present invention provides a high-precision absolute magnetic encoder, comprising: a vernier magnetic code disk, an incremental magnetic code disk, a Hall magnetic encoder chip, an AMR sensor chip, a subdivision chip, and a microcontroller. The Hall magnetic encoder chip is used to sense the magnetic signal of the vernier magnetic code disk and output an absolute angle position signal; the AMR sensor chip is used to sense the magnetic signal of the incremental magnetic code disk and output a sine / cosine voltage signal; the subdivision chip is used to receive the sine / cosine voltage signal and output an angle increment signal when the absolute magnetic encoder rotates; and the microcontroller is used to fuse the absolute angle position signal and the angle increment signal to output a high-precision angle position signal.

[0007] Furthermore, the vernier magnetic code disk is disposed on the inner ring of the magnetic code disk structure of the absolute magnetic encoder, and the incremental magnetic code disk is disposed on the outer ring of the magnetic code disk structure of the absolute magnetic encoder.

[0008] Furthermore, the vernier magnetic encoder disk has a resolution of 17 bits, and the Hall magnetic encoder chip outputs a 17-bit absolute angle position signal.

[0009] Furthermore, the incremental magnetic code disk has a resolution of 10 bits, and the subdivision chip outputs a 10-bit angle incremental signal.

[0010] Furthermore, the specific operation of the microcontroller in fusing the absolute angle position signal and the angle increment signal includes: using the high-precision angle increment as the lower ten bits of the final output encoder position signal, and using the higher seven bits of the Hall encoder chip as the higher seven bits of the final output encoder position signal.

[0011] Furthermore, the angle position signal output by the microcontroller is a 17-bit high-precision angle position signal.

[0012] The present invention also provides a signal processing method for the aforementioned high-precision absolute magnetic encoder, characterized in that the method includes the following steps:

[0013] S1. Obtain the magnetic signal of the standard magnetic code disk through the Hall magnetic encoder chip and output the absolute angle position signal;

[0014] S2. Obtain the magnetic signal of the incremental magnetic code disk through the AMR sensor chip and output sine and cosine voltage signals;

[0015] S3. Receive the sine and cosine voltage signals through the subdivision chip and output the angle increment signal when the absolute magnetic encoder rotates;

[0016] S4. The microcontroller fuses the absolute angle position signal and the angle increment signal to output a high-precision angle position signal.

[0017] Furthermore, the specific operation of microcontroller data fusion in step S4 includes the following steps:

[0018] S41. Power on and program initialization;

[0019] S42. Read the Hall magnetic encoder chip to obtain the absolute angle position signal, and use the absolute angle position signal as the power-on initial angle of the absolute magnetic encoder;

[0020] S43. Read the subdivision chip to obtain a high-precision angle increment signal;

[0021] S44. Merge two position data: use the high-precision angle increment as the lower ten bits of the final output encoder position signal, and use the higher seven bits of the Hall encoder chip as the higher seven bits of the final output encoder position signal.

[0022] S45 outputs a 17-bit high-precision angle position signal.

[0023] Furthermore, in step S42, the Hall magnetic encoder chip outputs a 17-bit absolute angle position signal.

[0024] Furthermore, in step S43, the subdivision chip outputs a 10-bit angle increment signal.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The absolute encoder of this invention features a vernier magnetic code disk on the inner ring, where a Hall sensor chip measures the absolute position of the encoder. An incremental magnetic code disk is set on the outer ring, where an AMR sensor chip and a subdivision chip measure the angular increment during encoder rotation. A microcontroller then fuses the two position data to output a high-precision angular position signal. This invention integrates two types of magnetic code disks into a single encoder, providing both absolute position upon encoder power-on and higher precision, higher resolution position information.

[0027] 2. This invention uses the 17-bit absolute angle position signal obtained from the Hall sensor chip as the initial power-on angle of the absolute magnetic encoder, and the 10-bit angle increment signal obtained from the subdivision chip. Then, by fusing the high-precision angle increment as the lower ten bits of the final output encoder position signal, and the higher seven bits of the Hall encoder chip as the higher seven bits of the final output encoder position signal, a 17-bit high-precision angle position signal is output, thereby improving the measurement accuracy of the encoder. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a structural block diagram of a high-precision absolute magnetic encoder provided in an embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram of the structure of a magnetic code disk for an absolute magnetic encoder provided in an embodiment of the present invention.

[0031] Figure 3 A flowchart of a signal processing method for an absolute magnetic encoder provided in an embodiment of the present invention.

[0032] Figure 4 This is a flowchart illustrating the operation of a microcontroller provided in an embodiment of the present invention.

[0033] Explanation of key figure labels:

[0034] 1. Vernier code disk; 2. Incremental code disk. Detailed Implementation

[0035] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0037] like Figure 1-2As shown, this embodiment of the invention provides a high-precision absolute magnetic encoder, including: a vernier magnetic code disk 1, an incremental magnetic code disk 2, a Hall magnetic encoder chip, an AMR sensor chip, a subdivision chip, and a microcontroller. The Hall magnetic encoder chip senses the magnetic signal of the vernier magnetic code disk 1 and outputs an absolute angle position signal; the AMR sensor chip senses the magnetic signal of the incremental magnetic code disk 2 and outputs a sine / cosine voltage signal; the subdivision chip receives the sine / cosine voltage signal and outputs an angle increment signal during the rotation of the absolute magnetic encoder; and the microcontroller fuses the absolute angle position signal and the angle increment signal to output a high-precision angle position signal.

[0038] Among them, the AMR sensor is a component that reduces resistance after a magnetic field is applied. Its function depends on the direction of the magnetic field lines relative to the component. It can sense magnetic signals and output sine and cosine signals according to the magnitude of the magnetic signal. The AMR sensor is used to convert the rotating magnetic field of the vernier code disk 1 into sine and cosine differential signals with a 90° phase difference.

[0039] In this embodiment of the invention, the magnetic code disk structure of the absolute magnetic encoder is a circular ring structure, such as... Figure 2 As shown, two rings of through holes are evenly distributed along the circumference of the magnetic code disk to form a vernier magnetic code disk 1 and an incremental magnetic code disk 2. The vernier magnetic code disk 1 and the incremental magnetic code disk 2 have different numbers of through holes. The vernier magnetic code disk 1 is set on the inner ring of the magnetic code disk structure of the absolute magnetic encoder, and the incremental magnetic code disk 2 is set on the outer ring of the magnetic code disk structure of the absolute magnetic encoder. The Hall magnetic encoder chip is electrically connected to the vernier magnetic code disk 1, and the AMR sensor chip is electrically connected to the incremental magnetic code disk 2. Correspondingly, the Hall magnetic encoder chip, AMR sensor chip, and subdivision chip also need to be arranged on the magnetic code disk. They can be connected and fixed by brackets or other means. The specific implementation method will not be elaborated here, as long as the required functions are achieved.

[0040] Furthermore, the vernier magnetic code disk 1 has a resolution of 17 bits, and the Hall magnetic encoder chip outputs a 17-bit absolute angle position signal; the incremental magnetic code disk 2 has a resolution of 10 bits, and the subdivision chip outputs a 10-bit angle increment signal.

[0041] Furthermore, this invention inputs the absolute angle position signal and the angle increment signal into a microcontroller. The microcontroller fuses these two position data to improve the measurement accuracy and resolution of the absolute magnetic encoder. The specific operation of the microcontroller fusing the absolute angle position signal and the angle increment signal includes: using the high-precision angle increment as the lower ten bits of the final output encoder position signal, and using the higher seven bits of the Hall encoder chip as the higher seven bits of the final output encoder position signal. The angle position signal output by the microcontroller is a 17-bit high-precision angle position signal, thereby achieving high-resolution angle measurement.

[0042] This invention features a vernier magnetic code disk on the inner ring, where a Hall sensor chip measures the absolute position of the encoder. An incremental magnetic code disk on the outer ring measures the angular increments during encoder rotation using an AMR sensor chip and a subdivision chip. A microcontroller then fuses the two position data to output a high-precision angular position signal. By integrating two types of magnetic code disks onto a single encoder, this invention provides both absolute position upon encoder power-on and higher precision, higher resolution position information.

[0043] After testing, the measurement accuracy of the absolute magnetic encoder of this invention can reach 0.00774°.

[0044] This invention also provides a signal processing method for the aforementioned high-precision absolute magnetic encoder, such as... Figure 3 As shown, the method includes the following steps:

[0045] S1. Obtain the magnetic signal of the standard magnetic code disk through the Hall magnetic encoder chip and output the absolute angle position signal.

[0046] S2. Obtain the magnetic signal of the incremental magnetic code disk through the AMR sensor chip and output sine and cosine voltage signals.

[0047] S3. Receives sine and cosine voltage signals through the subdivision chip and outputs the angle increment signal when the absolute magnetic encoder rotates.

[0048] S4. The microcontroller fuses the absolute angle position signal and the angle increment signal to output a high-precision angle position signal.

[0049] Among them, such as Figure 4 As shown, in step S4, the specific operation of microcontroller data fusion includes the following steps:

[0050] S41. Power on and program initialization.

[0051] S42. Read the Hall magnetic encoder chip to obtain the absolute angle position signal, and use the absolute angle position signal as the power-on initial angle of the absolute magnetic encoder.

[0052] Preferably, in this step, the Hall magnetic encoder chip outputs a 17-bit absolute angle position signal.

[0053] At this time, the 17-bit absolute angle position signal output by the Hall magnetic encoder chip is the coarse position signal output by the vernier magnetic code disk 1.

[0054] S43. Read the subdivision chip to obtain a high-precision angle increment signal.

[0055] Preferably, in this step, the subdivision chip outputs a 10-bit angle increment signal.

[0056] S44. Merge two position data: use the high-precision angle increment as the lower ten bits of the final output encoder position signal, and use the higher seven bits of the Hall encoder chip as the higher seven bits of the final output encoder position signal.

[0057] S45 outputs a 17-bit high-precision angle position signal.

[0058] This invention improves the measurement accuracy of the absolute magnetic encoder by using the 17-bit absolute angle position signal obtained from the Hall sensor chip as the initial power-on angle of the absolute magnetic encoder, and the 10-bit angle increment signal obtained from the subdivision chip. Then, through fusion, the high-precision angle increment is used as the lower ten bits of the final encoder position signal, and the higher seven bits of the Hall encoder chip are used as the higher seven bits of the final output encoder position signal, resulting in a 17-bit high-precision angle position signal. Testing shows that the measurement accuracy of the absolute magnetic encoder of this invention can reach 0.00774°.

[0059] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A high-precision absolute value magnetic encoder, characterized by, The application relates to an absolute value magnetic encoder, which comprises a cursor magnetic code disc, an incremental magnetic code disc, a Hall magnetic encoder chip, an AMR sensor chip, a subdivision chip and a single-chip microcomputer, the Hall magnetic encoder chip is used for inducting the magnetic signal of the cursor magnetic code disc and outputting an absolute angle position signal, the AMR sensor chip is used for inducting the magnetic signal of the incremental magnetic code disc and outputting a cosine voltage signal, the subdivision chip is used for receiving the cosine voltage signal and outputting an angle increment signal when the absolute value magnetic encoder rotates, the single-chip microcomputer is used for fusing the absolute angle position signal and the angle increment signal and outputting a high-precision angle position signal, the cursor magnetic code disc is arranged on the inner ring of a magnetic code disc structure of the absolute value magnetic encoder, the incremental magnetic code disc is arranged on the outer ring of the magnetic code disc structure of the absolute value magnetic encoder, the magnetic code disc structure is a circular ring structure, two rings of through holes are uniformly arranged along the circumference, the through holes of the inner ring form the cursor magnetic code disc, and the through holes of the outer ring form the incremental magnetic code disc. The resolution of the cursor magnetic code disc is 17-bit binary, and the Hall magnetic encoder chip outputs a 17-bit absolute angle position signal. The resolution of the incremental magnetic code disc is 10-bit binary, and the subdivision chip outputs a 10-bit angle increment signal. The specific operation of fusing the absolute angle position signal and the angle increment signal by the single-chip microcomputer comprises the following steps: taking the high-precision angle increment as the low ten bits of the final output encoder position signal, and taking the high seven bits of the Hall magnetic encoder chip as the high seven bits of the final output encoder position signal. The angle position signal output by the single-chip microcomputer is a 17-bit high-precision angle position signal. The method comprises the following steps:

2. A signal processing method for the high-precision absolute value magnetic encoder of claim 1, characterized in that, S1, acquiring the magnetic signal of a magnetic code disc through a Hall magnetic encoder chip and outputting an absolute angle position signal; S2, acquiring the magnetic signal of an incremental magnetic code disc through an AMR sensor chip and outputting a cosine voltage signal; S3, receiving the cosine voltage signal through a subdivision chip and outputting an angle increment signal when the absolute value magnetic encoder rotates; S4, fusing the absolute angle position signal and the angle increment signal through a single-chip microcomputer and outputting a high-precision angle position signal. The specific operation of data fusion of the single-chip microcomputer in the step S4 comprises the following steps:

3. The signal processing method of claim 2, wherein, S41, starting power-on and initializing a program; S42, reading the absolute angle position signal obtained by the Hall magnetic encoder chip and taking the absolute angle position signal as the initial angle of the absolute value magnetic encoder after power-on; S43, reading the high-precision angle increment signal obtained by the subdivision chip; S44, fusing two position data: taking the high-precision angle increment as the low ten bits of the final output encoder position signal, and taking the high seven bits of the Hall magnetic encoder chip as the high seven bits of the final output encoder position signal; S45, outputting a 17-bit high-precision angle position signal. In the step S42, the Hall magnetic encoder chip outputs a 17-bit absolute angle position signal.

4. The signal processing method of claim 3, wherein, In the step S43, the subdivision chip outputs a 10-bit angle increment signal.

5. The signal processing method of claim 4, wherein, ​

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