Encoder and measuring method and system based on reluctance principle

Abstract

The invention relates to the technical field of encoder measurement, and discloses an encoder based on the reluctance principle and a measurement method and system, and the encoder comprises a magnetic plate which is fixed on a motor rotor and is provided with a permanent magnet; the magnetic resistance sensor is fixed on the motor stator, the distance is the same as the polar distance between the N pole and the S pole of the permanent magnet, and the magnetic resistance sensor is arranged in the magnetic field of the magnetic plate; and an output signal of the magnetoresistive sensor is connected to the processor after being connected to the operational amplifier circuit. The method comprises the steps that the magnetoresistive sensor converts magnetic field changes into sine and cosine signals, and the sine and cosine signals are converted into digital quantity through the analog-to-digital converter after being conditioned and amplified; the processor determines the position of a sector where the magnetic plate is located by combining sine and cosine signals and symbols of the digital quantity, and obtains position information by combining the distance between the magnetoresistive sensors. The system comprises an encoder, a data acquisition module, a signal conditioning and conversion module and a position information calculation module. According to the invention, strong anti-interference capability and high precision can be ensured, the assembly process is simplified, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of encoder measurement technology, and in particular to an encoder based on the magnetoresistance principle and a measurement method and system. Background Art

[0002] An encoder is a device that converts angular displacement or linear displacement into an electrical signal. Correspondingly, encoders can be divided into rotary encoders and linear encoders. Rotary encoders are mainly used to measure the angle and angular velocity of rotating objects, while linear encoders are used to measure the displacement and velocity of linear motion. The resolution of rotary encoders can reach thousands or even tens of thousands of pulses per revolution, and the resolution of linear encoders can reach micron-level accuracy. Therefore, encoders are widely used in automation equipment that requires high-precision measurement, such as printing, packaging, medical treatment, machine tools, textiles, and robots. Encoders usually work with servo drives and programmable logic controllers (PLCs) to form a closed-loop position control system.

[0003] The output signals of encoders are of two types: incremental and absolute. Among them, the incremental encoder does not provide absolute position information. After the device is powered on, it needs to perform a return to origin action and then run according to the incremental position information. Therefore, the incremental encoder is easily affected by external interference, resulting in errors in the position accumulation calculation. The absolute encoder determines the encoding by mechanical position, and there is no need to memorize or find a reference point. Therefore, the absolute encoder has stronger anti-interference ability and higher accuracy than the incremental encoder. However, the absolute encoder also has the disadvantages of complex assembly process and high cost. Summary of the invention

[0004] To this end, the technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide an encoder and a measurement method and system based on the magnetic resistance principle, which can simplify the assembly process and reduce costs while ensuring strong anti-interference ability and high precision.

[0005] In order to solve the above technical problems, the present invention provides an encoder based on the magnetoresistance principle, comprising: A magnetic plate, fixed on the motor mover, on which permanent magnets are evenly distributed; A plurality of magnetoresistive sensors are fixed on the motor stator, the spacing between the magnetoresistive sensors is the same as the pole pitch between the N pole and the S pole of the permanent magnet, and the magnetoresistive sensors are placed in the magnetic field of the magnetic plate; An operational amplifier circuit, in which the sine signal and the cosine signal output by the magnetoresistive sensor are connected; A processor, wherein the sine signal and the cosine signal passing through the operational amplifier circuit are connected to the processor.

[0006] Furthermore, it also includes a sensor circuit board and a bias circuit, the operational amplifier circuit, the processor and the bias circuit are arranged on the sensor circuit board, the magnetoresistive sensor is fixed on the sensor circuit board, and the operational amplifier circuit and the bias circuit are arranged on the connection circuit between the processor and the magnetoresistive sensor.

[0007] The present invention also provides an encoder measurement method based on the magnetoresistance principle. When the encoder based on the magnetoresistance principle is used, the position information measurement process includes: The magnetic field of the magnetic plate moves with the motor rotor, and the magnetoresistive sensor converts the magnetic field changes into sine signals and cosine signals, and converts the sine signals and cosine signals into digital quantities after conditioning and amplification; the processor determines the sector position of the magnetic plate based on the signs of the sine signals, cosine signals, and digital quantities, and obtains the position information based on the correspondence between the sector position of the magnetic plate and the spacing of the magnetoresistive sensor.

[0008] Furthermore, when the magnetoresistive sensor converts the magnetic field change into a sine signal and a cosine signal, the amplitudes of the converted sine signal and cosine signal are: V sensor = k1 * Vi, Among them, V sensor is the amplitude of the sine signal and the cosine signal, Vi is the power supply voltage of the magnetoresistive chip of the magnetoresistive sensor, and k1 is the coefficient of the output signal amplitude of the magnetoresistive chip.

[0009] Furthermore, the sine signal and the cosine signal are conditioned and amplified and then converted into digital quantities respectively, including: The sine signal and cosine signal are subjected to voltage amplification and bias processing. The sine signal and cosine signal after voltage amplification and bias processing are: V output =k2* V sensor + V ref , Among them, V output are the sine and cosine signals after voltage amplification and bias processing, V sensor is the amplitude of the sine signal and the cosine signal, k2 is the amplification factor, V ref is the reference bias voltage; The sine signal and cosine signal after voltage amplification and bias processing are converted into digital quantities through analog-to-digital converters.

[0010] Further, the sector position of the magnetic plate is determined by combining the sine signal, the cosine signal, and the sign of the digital quantity, including: The tangent signal of the electrical angle is calculated according to the sine signal and the cosine signal. The calculation method of the tangent signal of the electrical angle is: tangent signal = absolute value of the sine signal / absolute value of the cosine signal; The tangent signal of the electrical angle is fitted to obtain an electrical angle value, wherein the electrical angle value ranges from 0° to 90°; The electrical angle value is expanded to 0° to 360° in combination with the sign of the digital quantity, and the expanded electrical angle value is the angle corresponding to the sector position where the magnetic plate is located.

[0011] Furthermore, when fitting the tangent signal of the electrical angle, the method used is polynomial fitting, specifically: θ' = a * (tanθ) 3 + b * (tanθ) 2 + c * (tanθ) + d, Among them, θ' is the electrical angle value obtained by fitting, a, b, c, d are polynomial fitting coefficients, and tanθ is the tangent signal of the electrical angle.

[0012] Furthermore, the electrical angle value is extended to 0°~360° in combination with the sign of the digital quantity, specifically: When the sign of the digital quantity corresponding to the sine signal is positive and the sign of the digital quantity corresponding to the cosine signal is positive, the expanded electrical angle value is the current electrical angle value that falls within the first quadrant; When the sign of the digital quantity corresponding to the sine signal is positive and the sign of the digital quantity corresponding to the cosine signal is negative, the expanded electrical angle value is the current electrical angle value that falls within the second quadrant; When the sign of the digital quantity corresponding to the sine signal is negative and the sign of the digital quantity corresponding to the cosine signal is negative, the expanded electrical angle value is the current electrical angle value that falls within the third quadrant; When the sign of the digital quantity corresponding to the sine signal is negative and the sign of the digital quantity corresponding to the cosine signal is positive, the expanded electrical angle value is the current electrical angle value that falls within the fourth quadrant.

[0013] Furthermore, the position information is obtained according to the correspondence between the sector position of the magnetic plate and the spacing between the magnetoresistive sensors, specifically: S=D / 360*θ'', Among them, S is the position information finally measured by the encoder based on the magnetoresistive principle, D is the spacing of the magnetoresistive sensor, and θ'' is the angle corresponding to the sector position where the magnetic plate is located.

[0014] The present invention also provides an encoder measurement system based on the magnetoresistance principle, comprising: The encoder based on the magnetoresistive principle, the data acquisition module, the signal conditioning and conversion module, and the position information calculation module, The data acquisition module is used to receive the sine signal and cosine signal output by the magnetoresistive sensor, and transmit the sine signal and cosine signal to the signal conditioning and conversion module and the position information calculation module; The signal conditioning and conversion module is used to convert the sine signal and the cosine signal into digital quantities after conditioning and amplification, and transmit the digital quantities to the position information calculation module; The position information calculation module is used to control the processor to determine the sector position of the magnetic plate in combination with the sine signal, cosine signal, and the sign of the digital quantity, and obtain the position information according to the correspondence between the sector position of the magnetic plate and the spacing of the magnetoresistive sensor.

[0015] The above technical solution of the present invention has the following beneficial effects compared with the prior art: The present invention senses the position change of the mover through a magnetoresistive sensor, and on this basis calculates the position information through the measurement results of the magnetoresistive sensor. The obtained position information is an absolute position with strong anti-interference ability and high precision. At the same time, the encoder in the present invention has a simple structure, which can effectively simplify the assembly process and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein: Figure 1 Schematic diagram of the structure of an encoder based on the magnetoresistance principle in a preferred embodiment of the present invention.

[0017] Figure 2 It is a functional block diagram of a sensor circuit board in an encoder based on the magnetoresistive principle in a preferred embodiment of the present invention.

[0018] Figure 3 1 is an output signal diagram of a magnetoresistive sensor in an encoder based on the magnetoresistive principle in a preferred embodiment of the present invention.

[0019] Figure 4 It is a circuit diagram of an operational amplifier circuit and a bias circuit in an encoder based on the magnetoresistive principle in a preferred embodiment of the present invention.

[0020] Figure 5 It is a flow chart of an encoder measurement method based on the magnetoresistance principle in a preferred embodiment of the present invention.

[0021] Explanation of the reference numerals in the specification: 1. mover; 2. magnetic plate; 3. stator; 4. sensor circuit board. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention. Embodiment 1

[0023] Reference Figure 1 As shown, the present invention discloses an encoder based on the magnetoresistance principle, including a magnetic plate 2, a plurality of magnetoresistance sensors, an operational amplifier circuit and a processor. The magnetic plate 2 is fixed on the motor mover 1, on which are evenly distributed permanent magnets. The magnetic plate 2 moves with the motor mover 1 to provide a magnetic field to the magnetoresistance sensor. A plurality of magnetoresistance sensors are fixed on the motor stator 3. In this embodiment, the magnetoresistance sensor is fixed on the side of the motor stator 3. The spacing of the magnetoresistance sensor is the same as the pole pitch between the N pole and the S pole of the permanent magnet. The magnetoresistance sensor is placed in the magnetic field of the magnetic plate 2. In this embodiment, the spacing of the magnetoresistance sensor is set, and the pole pitch between the N pole and the S pole of the permanent magnet is 12.5 mm. The sine signal and cosine signal output by the magnetoresistance sensor are connected to the operational amplifier circuit, and the sine signal and cosine signal after the operational amplifier circuit are connected to the processor.

[0024] In this embodiment, the encoder based on the magnetoresistive principle further includes a sensor circuit board 4 and a bias circuit. The functional block diagram of the sensor circuit board 4 is shown in FIG. Figure 2 As shown, the operational amplifier circuit, the processor and the bias circuit are arranged on the sensor circuit board 4, and the magnetoresistive sensor is fixed on the sensor circuit board 4. The magnetoresistive sensor is fixed on the motor stator 3 through the sensor circuit board 4. The number of sensor circuit boards 4 is determined according to the actual situation. Multiple magnetoresistive sensors can be arranged on one sensor circuit board 4 or on multiple sensor circuit boards 4, and the spacing between the magnetoresistive sensors and the pole pitch between the N pole and the S pole of the permanent magnet can be ensured to be the same. Figure 1 , Figure 2 As shown, in this embodiment, multiple sensors are arranged on multiple sensor circuit boards 4 as an example, the magnetoresistive sensors are welded on the sensor circuit boards 4, and the multiple sensor circuit boards 4 are spliced ​​together and fixed on the motor mover 1. The operational amplifier circuit and the bias circuit are arranged on the connection circuit between the processor and the magnetoresistive sensor, and are used to amplify and bias the output signal of the magnetoresistive sensor. Embodiment 2

[0025] like Figure 5 As shown, the present invention also discloses an encoder measurement method based on the magnetoresistance principle. When the encoder based on the magnetoresistance principle in the first embodiment is used, the process of measuring the position information includes the following steps: S1: The magnetic field of the magnetic plate 2 moves with the motor rotor 1, and the magnetoresistive sensor converts the magnetic field changes into sine and cosine signals. When the encoder is working, the magnetoresistive sensor senses the magnetic field changes and outputs Figure 3The example diagrams of continuous sine and cosine signals are shown in Figure 1. Figure 3 The X-axis output is a cosine signal and the Y-axis output is a sine signal.

[0026] When the magnetoresistive sensor converts the magnetic field change into sine and cosine signals, the amplitudes of the converted sine and cosine signals are: V sensor = k1 * Vi, Among them, V sensor is the amplitude of the sine signal and the cosine signal, Vi is the power supply voltage of the magnetoresistive chip of the magnetoresistive sensor, k1 is the coefficient of the output signal amplitude of the magnetoresistive chip, and the value of k1 is determined by the chip itself. In this embodiment, Vi=2.5V, k1=0.75%, V sensor = ±0.75% * 2.5V = ±18.75mV.

[0027] S2: The sine signal and cosine signal are conditioned and amplified and then converted into digital quantities.

[0028] S2-1: The amplitude of the sine signal and cosine signal output by the magnetoresistive sensor is small, so the sine signal and cosine signal are firstly amplified and biased. Figure 4 The circuit diagram of the operational amplifier circuit and the bias circuit is shown, where U4 is an operational amplifier, ADC2_IN5 and ADC1_IN9 are the inputs of the analog-to-digital converter. The input signals of the circuit, i.e., the signal outputs of the magnetoresistive sensor are X1-, X1+, Y1-, and Y1+, where X1- is a negative cosine signal, X1+ is a positive cosine signal, Y1- is a negative sine signal, and Y1+ is a positive sine signal; the output of the circuit is a digital quantity processed by the analog-to-digital converter.

[0029] The sine and cosine signals after voltage amplification and bias processing are: V output =k2* V sensor + V ref , Among them, V output are the sine and cosine signals after voltage amplification and bias processing, V sensor is the amplitude of the sine signal and the cosine signal, k2 is the magnification; in this embodiment, Figure 4 R4 = R10, R1 = R16, magnification k2 = R1 / R4 = R16 / R10 = 56, V ref =1.25V, V output =±0.75% * 2.5V * 56 + 1.25V = 0.2V ~2.3V.

[0030] S2-2: The sine signal and cosine signal after voltage amplification and bias processing are converted into digital quantities through analog-to-digital converters.

[0031] S3: Determine the sector position where the magnetic plate 2 is located by combining the sine signal, the cosine signal and the sign of the digital quantity.

[0032] S3-1: The position calculation of the sensor is based on the inverse tangent algorithm. First, the tangent signal of the electrical angle is calculated based on the sine signal and the cosine signal. The calculation method of the tangent signal of the electrical angle is: tangent signal = absolute value of the sine signal / absolute value of the cosine signal, that is: tanθ = |sinθ| / |cosθ|, Among them, tanθ is the tangent signal of the electrical angle, sinθ is the sine signal, and cosθ is the cosine signal.

[0033] S3-2: Fitting the tangent signal of the electrical angle to obtain the electrical angle value, the electrical angle value ranges from 0° to 90°.

[0034] When fitting the tangent signal of the electrical angle, the method used is polynomial fitting, specifically: θ' = a * (tanθ) 3 + b * (tanθ) 2 + c * (tanθ) + d, Wherein, θ' is the electrical angle value obtained by fitting, and a, b, c, and d are polynomial fitting coefficients. In this embodiment, a=1E-7, b=-9E-5, c=0.0174, and d=-0.0079.

[0035] S3-3: Expand the electrical angle value to 0°~360° based on the sign of the digital quantity. The expanded electrical angle value is the angle corresponding to the sector position where the magnetic plate 2 is located.

[0036] Table 1 shows a method for expanding the electrical angle value to 0°~360° by combining the sign of the digital quantity.

[0037]

[0038] Table 1 Expansion method table of electrical angle values

[0039] As shown in Table 1, the method for expanding the electrical angle value is specifically: When the sign of the digital quantity corresponding to the sine signal is positive and the sign of the digital quantity corresponding to the cosine signal is positive, the expanded electrical angle value is the current electrical angle value that falls within the first quadrant; When the sign of the digital quantity corresponding to the sine signal is positive and the sign of the digital quantity corresponding to the cosine signal is negative, the expanded electrical angle value is the current electrical angle value that falls within the second quadrant; When the sign of the digital quantity corresponding to the sine signal is negative and the sign of the digital quantity corresponding to the cosine signal is negative, the expanded electrical angle value is the current electrical angle value that falls within the third quadrant; When the sign of the digital quantity corresponding to the sine signal is negative and the sign of the digital quantity corresponding to the cosine signal is positive, the expanded electrical angle value is the current electrical angle value that falls within the fourth quadrant.

[0040] For example, assuming that the electrical angle value fitted in S3-2 is 45°, if the sign of the digital quantity corresponding to the sine signal is positive and the sign of the digital quantity corresponding to the cosine signal is positive, then the expanded electrical angle value is 45°; if the sign of the digital quantity corresponding to the sine signal is positive and the sign of the digital quantity corresponding to the cosine signal is negative, then the expanded electrical angle value is 135°; if the sign of the digital quantity corresponding to the sine signal is negative and the sign of the digital quantity corresponding to the cosine signal is negative, then the expanded electrical angle value is 225°; if the sign of the digital quantity corresponding to the sine signal is negative and the sign of the digital quantity corresponding to the cosine signal is positive, then the expanded electrical angle value is 315°.

[0041] S4: Obtain position information based on the corresponding relationship between the sector position of the magnetic plate 2 and the spacing between the magnetoresistive sensors. The position information is calculated as follows: S=D / 360*θ'', Among them, S is the position information finally measured by the encoder based on the magnetoresistance principle, D is the spacing of the magnetoresistance sensor, that is, the pole pitch between the N pole and the S pole of the permanent magnet, and θ'' is the angle corresponding to the sector position of the magnetic plate 2, that is, the expanded electrical angle value.

[0042] When the encoder measures position information, the controller and encoder use the serial port to communicate periodically, so that real-time position information can be obtained. Embodiment 3

[0043] The present invention also discloses an encoder measurement system based on the magnetoresistance principle, comprising the encoder based on the magnetoresistance principle in the first embodiment, a data acquisition module, a signal conditioning and conversion module, and a position information calculation module.

[0044] The data acquisition module is used to receive the sine signal and cosine signal output by the magnetoresistive sensor, and transmit the sine signal and cosine signal to the signal conditioning and conversion module and the position information calculation module; the signal conditioning and conversion module is used to convert the sine signal and cosine signal into digital quantities after conditioning and amplification, and transmit the digital quantities to the position information calculation module; the position information calculation module is used to control the processor to determine the sector position of the magnetic plate 2 based on the signs of the sine signal, cosine signal and digital quantity, and obtain the position information according to the correspondence between the sector position of the magnetic plate 2 and the spacing of the magnetoresistive sensor.

[0045] The encoder designed by the present invention is an absolute, linear encoder. The present invention senses the position change of the mover 1 through a magnetoresistive sensor, and on this basis calculates the position information through the measurement result of the magnetoresistive sensor. The obtained position information is an absolute position, with strong anti-interference ability and high precision; at the same time, the encoder of the present invention has a simple structure, which can effectively simplify the assembly process and reduce costs.

[0046] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0047] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0048] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0049] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0050] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. An encoder based on the magnetoresistive principle, characterized in that: include: A magnetic plate, fixed on the motor mover, on which permanent magnets are evenly distributed; A plurality of magnetoresistive sensors are fixed on the motor stator, the spacing between the magnetoresistive sensors is the same as the pole pitch between the N pole and the S pole of the permanent magnet, and the magnetoresistive sensors are placed in the magnetic field of the magnetic plate; An operational amplifier circuit, in which the sine signal and the cosine signal output by the magnetoresistive sensor are connected; A processor, wherein the sine signal and the cosine signal passing through the operational amplifier circuit are connected to the processor.

2. The encoder based on the magnetoresistive principle according to claim 1, characterized in that: It also includes a sensor circuit board and a bias circuit, the operational amplifier circuit, the processor and the bias circuit are arranged on the sensor circuit board, the magnetoresistive sensor is fixed on the sensor circuit board, and the operational amplifier circuit and the bias circuit are arranged on the connection circuit between the processor and the magnetoresistive sensor.

3. An encoder measurement method based on the magnetoresistance principle, characterized in that: When using the encoder based on the magnetoresistive principle as described in claim 1 or 2, the process of measuring the position information includes: The magnetic field of the magnetic plate moves with the motor rotor, and the magnetoresistive sensor converts the magnetic field changes into sine signals and cosine signals, and converts the sine signals and cosine signals into digital quantities after conditioning and amplification; the processor determines the sector position of the magnetic plate based on the signs of the sine signals, cosine signals, and digital quantities, and obtains the position information based on the correspondence between the sector position of the magnetic plate and the spacing of the magnetoresistive sensor.

4. The encoder measurement method based on the magnetoresistance principle according to claim 3 is characterized in that: When the magnetoresistive sensor converts the magnetic field change into a sine signal and a cosine signal, the amplitudes of the converted sine signal and cosine signal are: V sensor = k1 * We, Among them, V sensor is the amplitude of the sine signal and the cosine signal, Vi is the power supply voltage of the magnetoresistive chip of the magnetoresistive sensor, and k1 is the coefficient of the output signal amplitude of the magnetoresistive chip.

5. The encoder measurement method based on the magnetoresistance principle according to claim 3, characterized in that: The sine signal and the cosine signal are conditioned and amplified and then converted into digital quantities respectively, including: The sine signal and cosine signal are subjected to voltage amplification and bias processing. The sine signal and cosine signal after voltage amplification and bias processing are: V output =k2* V sensor + V ref , Among them, V output are the sine and cosine signals after voltage amplification and bias processing, V sensor is the amplitude of the sine signal and the cosine signal, k2 is the amplification factor, V ref is the reference bias voltage; The sine signal and cosine signal after voltage amplification and bias processing are converted into digital quantities through analog-to-digital converters.

6. The encoder measurement method based on the magnetoresistance principle according to claim 3, characterized in that: Determining the sector position of the magnetic plate by combining the sine signal, the cosine signal, and the sign of the digital quantity includes: The tangent signal of the electrical angle is calculated according to the sine signal and the cosine signal. The calculation method of the tangent signal of the electrical angle is: tangent signal = absolute value of the sine signal / absolute value of the cosine signal; The tangent signal of the electrical angle is fitted to obtain an electrical angle value, wherein the electrical angle value ranges from 0° to 90°; The electrical angle value is expanded to 0° to 360° in combination with the sign of the digital quantity, and the expanded electrical angle value is the angle corresponding to the sector position where the magnetic plate is located.

7. The encoder measurement method based on the magnetoresistance principle according to claim 6, characterized in that: When fitting the tangent signal of the electrical angle, the method used is polynomial fitting, specifically: θ’= a * (tanθ) 3 + b * (tanθ) 2 + c * (tanθ) + d, Among them, θ' is the electrical angle value obtained by fitting, a, b, c, d are polynomial fitting coefficients, and tanθ is the tangent signal of the electrical angle.

8. The encoder measurement method based on the magnetoresistance principle according to claim 6, characterized in that: The electrical angle value is extended to 0°~360° in combination with the sign of the digital quantity, specifically: When the sign of the digital quantity corresponding to the sine signal is positive and the sign of the digital quantity corresponding to the cosine signal is positive, the expanded electrical angle value is the current electrical angle value that falls within the first quadrant; When the sign of the digital quantity corresponding to the sine signal is positive and the sign of the digital quantity corresponding to the cosine signal is negative, the expanded electrical angle value is the current electrical angle value that falls within the second quadrant; When the sign of the digital quantity corresponding to the sine signal is negative and the sign of the digital quantity corresponding to the cosine signal is negative, the expanded electrical angle value is the current electrical angle value that falls within the third quadrant; When the sign of the digital quantity corresponding to the sine signal is negative and the sign of the digital quantity corresponding to the cosine signal is positive, the expanded electrical angle value is the current electrical angle value that falls within the fourth quadrant.

9. The encoder measurement method based on the magnetoresistance principle according to claim 6, characterized in that: The position information is obtained according to the corresponding relationship between the sector position of the magnetic plate and the spacing between the magnetoresistive sensors, specifically: S=D / 360*θ'', Among them, S is the position information finally measured by the encoder based on the magnetoresistive principle, D is the spacing of the magnetoresistive sensor, and θ'' is the angle corresponding to the sector position where the magnetic plate is located.

10. An encoder measurement system based on the magnetoresistance principle, characterized in that: include: The encoder based on the magnetoresistive principle, the data acquisition module, the signal conditioning and conversion module, and the position information calculation module as described in claim 1 or 2, The data acquisition module is used to receive the sine signal and cosine signal output by the magnetoresistive sensor, and transmit the sine signal and cosine signal to the signal conditioning and conversion module and the position information calculation module; The signal conditioning and conversion module is used to convert the sine signal and the cosine signal into digital quantities after conditioning and amplification, and transmit the digital quantities to the position information calculation module; The position information calculation module is used to control the processor to determine the sector position of the magnetic plate in combination with the sine signal, cosine signal, and the sign of the digital quantity, and obtain the position information according to the correspondence between the sector position of the magnetic plate and the spacing of the magnetoresistive sensor.

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